2014 Accuray / AERO Users’ Meeting The Frontiers of Image-Guidance: Margins, Motion & Adaptation

Minneapolis, MN • May 6-7, 2014 AERO® is a users’ community and website  that fosters the exchange of best practices and discussion of important needs and solutions  in the field of precision radiation oncology.

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MEMBERSHIP Membership is free and open to all users of TomoTherapy® and CyberKnife® Systems. MEMBER BENEFITS • Online peer-to-peer discussion of treatment experiences • Dedicated physics discussion group to foster exchange of technical information and developments • News about publications, scientific conferences, and Users’ Meetings • Resources including educational and training opportunities, clinical research and program development

AERO Ad_ProgramPages.indd 1 4/14/14 6:16 PM The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014

Welcome Reception Hotel Ivy – Gershwin Room (connected to the Hilton Minneapolis) 6:30 pm – 8:30 pm Cocktails and Hors d’oeuvres Electronic Poster Viewing

Local Host: Susanta K. Hui, Ph.D., DABR Associate Professor Therapeutic Radiology and Masonic Cancer Center University of Minnesota, Minneapolis

Wlecome-ReceptionAd.indd 1 4/21/14 8:55 AM The Frontiers of Image-Guidance: Margins, Motion & Adaptation The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014 7 a.m. – 5 p.m. • May 7, 2014

Welcome to the 2014 Accuray-AERO Users’ Meeting, Frontiers of Image Guidance: Margins, Motion, and Adaptation. Users of the CyberKnife® and TomoTherapy® Systems have joined the Accuray team for a program of science and technology dedicated to sharing and discussing treatment experiences and innovation. Our goal is to provide a forum to collectively work to provide expanded treatment options for patients worldwide, and further improve patient care.

We are excited also about additional activities we have arranged around the Users’ Meeting, especially the satellite meeting, TomoTherapy for Breast Cancer: Realities and Results. Clinicians from across the globe will join Accuray scientists and physicists in presenting the challenges and great promise of the TomoTherapy System for the treatment of breast cancer. As is true of the Users’ Meeting, ample opportunities for participant feedback on the performance of the TomoTherapy System will be provided. The Accuray team is grateful for your participation in both of these events.

We thank all those who agreed to present at this year’s meeting, and the many who submitted excellent abstracts describing physics and clinical work with the CyberKnife and TomoTherapy Systems. And please, don’t hesitate to approach an Accuray employee and tell them what you think about their products—this is a users’ meeting, and they are here to listen to your concerns and to think about how to address them. The opportunities for learning, sharing, and feedback will continue in the months to come on the redesigned AERO Web site – visit at acccurayexchange.com.

Thank you! We hope you enjoy yourself in Minneapolis.

Eric Lartigau, M.D., Ph.D. President, Accuray Exchange in Radiation Oncology Acting Chief Medical Officer, Accuray Incorporated The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014

SECOND FLOOR

Registration: Marquette Foyer

General Session and Main Meeting Area: Marquette Ballrooms I - V Minneapolis Grand Ballroom

Meals & Posters: Marquette Ballrooms I-V Minneapolis Grand Ballroom Marquette Foyer Physics Breakout: Minneapolis G

AERO Board Meeting: Minneapolis F

TomoTherapy for Breast Cancer Meeting: Minneapolis E

Electronic Poster Viewing: Director’s Row 1 THIRD FLOOR Offsite Reception: Banquet Kitchen Hotel Ivy 201 S 11th St, Minneapolis via Skyway, Service Corridor Gershwin Room A G Minneapolis G

MINNEAPOLIS GRAND BALLROOM

D B F Minneapolis F

C E Minneapolis E

Rochester Guest Room Pre-Convene Elevators Escalators

Restroom

Restroom Board Board Board Directors Red Wing Directors Directors Directors Duluth Room 1 Room 2 Room 3 Row 1 Room Row 2 Row 3 Row 4

Directors Row 1 MEETING AGENDA The Frontiers of Image-Guidance: Margins, Motion & Adaptation The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014 7 a.m. – 5 p.m. • May 7, 2014

Tuesday, May 6 Wednesday, May 7

7:00 am Breakfast & Poster Viewing 7:30 am (7:00 AM - 7:45 AM) 8:00 am The Frontiers of Image- 8:30 am Guidance: Margins, Motion, & Adaptation 9:00 am (7:45 AM - 9:30 AM) 9:30 am Break (9:30 AM - 9:45 AM)

10:00 am …cont’d 10:30 am The Frontiers of Image- Guidance: Margins, Motion, & 11:00 am Adaptation 11:30 am (9:45 AM - 12:00 PM)

12:00 pm Lunch (12:00 pm - 12:30 pm) Lunch & Networking 12:30 pm Poster Viewing (12:00 PM - 1:00PM) TomoTherapy for Breast 1:00 pm Cancer: Realities and Results (12:30 PM - 2:00 PM) 1:30 pm Scientific Talks Scientific Talks 2:00 pm Break (2:00 pm - 2:15 PM) (Physics) (Clinical) (1PM - 4:00 PM) (1PM - 4:00 PM) 2:30 pm Electronic Poster 3:00 pm …cont’d Viewing TomoTherapy for Breast 3:30 pm Transition to General Session Cancer: Realities and Results (1:00 PM - 4:00 pm (2:15 PM - 5:00 PM) 6:00 PM) 4:30 pm Closing Session 5:00 pm (4:00 PM - 5:00 PM) Scientific Poster Presentations 5:30 pm (5:00 PM - 6:30 PM) 6:00 pm Minneapolis Hilton 6:30 pm Room Locations 7:00 pm Welcome Reception Minneapolis E 7:30 pm (6:30 PM - 8:30 PM) Minneapolis D 8:00 pm Marquette Ballroom I - V 8:30 pm Minneapolis G

Directors Row 1

Minneapolis PreFunction Area

Hotel Ivy - Gershwin Room The Frontiers of Image-Guidance: Margins, Motion & Adaptation The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014 7 a.m. – 5 p.m. • May 7, 2014

May 6 Agenda

• 12:00 pm – 5:00 pm: SATELLITE MEETING: TomoTherapy® for Breast Cancer: Realities and Results • 5:00 pm – 6:30 pm: Poster Presentation Session • 6:30 pm – 8:30 pm: Welcome Reception

May 7 Agenda

• 7:00 a.m Breakfast

• 7:45 – 8:30: Accuray Presentation ºº Welcome, Kelly Londy, EVP, Chief Commercial Officer and Andy Kirkpatrick, SVP and General Manager, Americas ºº Roadmap Discussion, Rob Hill, SVP Engineering & Calvin Maurer, PhD, VP and Chief Technology Officer ºº AERO Session, Prof. Eric P. Lartigau, MD, PhD, Chief Medical Officer

• 8:30 – 9:30: Experience with Advanced Accuray Technologies (MODERATOR: John Kresl, MD, PHD, Phoenix CyberKnife and Radiation Oncology Center) ºº Clinical Experience with Lung Optimized Treatment for CyberKnife SBRT ›› Megan Gannaway, BS, RTT ºº Clinical Experience with the CyberKnife M6 ›› Pr. Alexander Muacevic, MD; European CyberKnife Center Munich ºº Clinical Experience with TomoTherapy HDA and TomoEDGE ›› Florian Sterzing, MD; Department of Radiation Oncology, University Hospital Heidelberg ºº TomoTherapy Treatment Planning with VoLO ›› Mark Geurts, MS DABR CQE; Department of Medical Physics, University of Wisconsin

• 9:30 – 9:45: Break

• 9:45 – noon – Keynote Addresses (MODERATOR: Eric Lartigau, MD, PhD) ºº 9:45 – 10:15: Twenty Years of Robotic Radiosurgery (Iris C. Gibbs, MD, Department of Radiation Oncology, Stanford University) ºº 10:15-10:30: Tumor bed boost integration during whole breast radiotherapy – Pierfrancesco Franco, M; Radiation Oncology Department, Tomotherapy Unit, Ospedale Regionale ‘U. Parini’, AUSL Valle d’Aosta, Italy The Frontiers of Image-Guidance: Margins, Motion & Adaptation The Frontiers of Image-Guidance: Margins, Motion & Adaptation 7 a.m. – 5 p.m. • May 7, 2014 7 a.m. – 5 p.m. • May 7, 2014

ºº 10:30-10:45: CyberKnife prostate SBRT -- Robert M. Meier, MD; Swedish Cancer Center, Seattle, WA ºº 10:45-11:00: CyberKnife SBRT for Early Stage Lung Cancer and the Impact of Motion on Chest Wall Dosimetry – Eric Schreiber, PhD; Department of Radiation Oncology, University of North Carolina at Chapel Hill

• 11:00-11:45: International Consortium on Total Marrow Irradiation (Susanta K Hui, PhD, Chair; Therapeutic Radiology, University of Minnesota) ºº Safety And Efficacy Of Adjuvant Low Dose Total Marrow Irradiation In Patients With Relapsed Multiple Myeloma ›› Dr. Tessa de Vin, Department of Radiation Oncology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium ºº Practical Image Guided Radiotherapy for Hypofractionated Upper and Lower Body Total Marrow Irradiation ›› Dr. Stefano Vagge, IRCCS San Martino IST National Cancer Research Institute and University, Genoa, Italy ºº Dosimetric comparison of TomoTherapy and VMAT in Total Marrow Irradiation ›› Dr. Lukasz Matulewicz, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice, Poland

• Noon – Lunch/networking

• 1:00 – 4:00: Scientific Program ºº Minneapolis G ›› 1:00 – 2:30 TomoTherapy Physics ›› 2:30 – 4:00 CyberKnife Physics ºº Marquette Ballroom I – V ›› 1:00 – 2:30 CyberKnife Clinical ›› 2:30 – 4:00 TomoTherapy Clinical

• 4:00- 5:00 User Input Session: Feedback and Ideas for Product Enhancement and Closing session (Eric Lartigau, MD, PhD, Acting Chief Medical Officer, Rob Hill, SVP Engineering, Calvin Maurer, PhD, VP and Chief Technology Officer, Corey Lawson, Sr. Director, TomoTherapy Brand Management, Terry Chang, Director, CyberKnife Marketing, Andrew Fuller, Sr. Product Manager, Treatment Planning & Data Management, and Susan Hopkins, Global VP, Patient Advocacy and Marketing) TomoTherapy® BREAST SYMPOSIUM

INVITED TALKS ABSTRACTS The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Twenty years of Robotic Radiosurgery Iris C. Gibbs, MD Department of Radiation Oncology, Stanford University

The year 2014 marks the 20th anniversary of the first robotic image-guided radiosurgery treatment that was performed in June 1994 under the leadership and innovative ideas of Dr. John Adler at Stanford University. The field of robotic radiosurgery emerged from neurosurgery and radiation medicine by combining concepts of image-guidance, stereotaxy, and robotics to address the need to accurately target key areas within the neurological axis. Robotic radiosurgery transformed neurosurgery and radiotherapy and is now an essential part of daily practice. In many ways the advances of robotic radiosurgery have mirrored innovations in other industries, first offering a tool to improve efficiency, then leading to the application of the technology beyond the neuraxis to extracranial body sites. With the innovations of Synchrony, robotic radiosurgery crossed new frontiers and transcended barriers of motion management. Over the past 2 decades, the lives of thousands of patients have been changed and numerous contributions to academic medicine have been made, yet the story is not over. As the technology of robotic radiosurgery matures, it is ever more important to continue to extend the concepts founded in this extraordinary technology and to create new possibilities.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Intensity-modulated adjuvant whole breast radiation delivered with static angle tomotherapy (TomoDirect): a prospective case series Pierfrancesco Franco1 • Michele Zeverino2 • Fernanda Migliaccio1 • Piera Sciacero1 • Domenico Cante1 • Valeria Casanova Borca2 • Paolo Torielli1 • Cecilia Arrichiello2 • Giuseppe Girelli1 • Gianmauro Numico3 • Maria Rosa La Porta1 • Santi Tofani2 • Umberto Ricardi4

1Radiation Oncology Department - Tomotherapy Unit; 2Medical Physics Department; 3Medical Oncology Department - AUSL valle d’Aosta, Aosta, Italy. 4Department of Oncology - Radiation Oncology - University of Torino, Turin, Italy.

Objectives: To report the 2-year outcomes of whole breast intensity-modulated radiotherapy (IMRT) after conserving surgery for early breast cancer (EBC) delivered with static angle tomotherapy (TomoDirect) (TD).

Methods: A prospective cohort of 120 EBC patients underwent whole breast IMRT with TD between 2010 and 2012. Radiation was delivered to a conventionally fractionated whole breast total dose of 50 Gy with TD, followed by a sequential conventionally fractionated tumor bed boost dose of 10–16 Gy with helical tomotherapy (HT). Clinical endpoints include acute and late toxicity, cosmesis, quality of life and local control.

Results: Median follow-up was 24 months (range 12–36 months); maximum detected acute skin toxicity was G0 22 %; G1 63 %; G2 12 % and G3 3 %. Predictors of acute dermatitis were as follows: volume of the whole breast minus boost volume receiving 105, 110 and 115 % of prescription dose, whole breast and boost volume, breast thickness and soft tissue thickness. Late skin toxicity was mild with no G2-events. Cosmesis was good/excellent in 91.7 %of patients and fair/poor in 8.3 %. Quality of life was preserved over time, but for fatigue, transiently increased.

Conclusions: Adjuvant whole breast IMRT delivered sequentially with both TD and HT provides consistent clinical results. An observed unintended excessive dose outside the tumor bed might increase acute toxicity and eventually affect long-term clinical endpoints. The incorporation of the boost dose within the whole breast phase employing a simultaneous integrated boost (SIB) approach might mitigate this issue. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Intensity-modulated and hypofractionated simultaneous integrated boost adjuvant breast radiation employing static ports of Tomotherapy (TomoDirect): a prospective phase II trial Pierfrancesco Franco1 • Michele Zeverino2 • Fernanda Migliaccio1 • Domenico Cante1 • Piera Sciacero1 • Valeria Casanova Borca2 • Paolo Torielli1 • Cecilia Arrichiello2 • Giuseppe Girelli1 • Maria Rosa La Porta1 • Santi Tofani2 • Gianmauro Numico3 • Umberto Ricardi4

1Radiation Oncology Department - Tomotherapy Unit 2Medical Physics Department 3Medical Oncology Department, AUSL Valle d’Aosta, Aosta, Italy 4Department of Oncology - Radiation Oncology, University of Torino, Turin, Italy

Objectives: To report the 1-year outcomes of a prospective phase II study on hypofractionated whole-breast intensity-modulated radiotherapy (IM-WBRT) with a simultaneous integrated boost (SIB) to the tumor bed delivered with static ports of tomotherapy (TomoDirect) (TD).

Methods: A prospective cohort of 82 patients was enrolled between 2011 and 2012. Treatment schedule consisted of 45 Gy/20 fractions to the whole breast and 50 Gy/20 fractions to the surgical bed delivered concomitantly with TD over 4 weeks. A one-armed optimal two-stage Simon’s design was selected to test the hypothesis that treatment modality under investigation would decrease acute skin toxicity over historical data using conventional fractionation and sequential boost. Primary endpoint was acute skin toxicity. Secondary endpoints included late toxicity, cosmesis,quality of life and local control.

Results: Median follow-up was 12 months (range 6–18). Maximum detected acute skin toxicity was G0 41 %; G1 53 %; G2 6 %; G3 <1 %. With two G2–G3 acute skin toxicity events in the first stage and four in the second, the study fulfilled the requirements for the definition of the treatment approach under investigation as promising. Late skin toxicity was mild with no >G2 events. Cosmesis was good/excellent in 91 % of patients and fair/poor in 9 %. Quality of life was preserved over time, with the exception of fatigue, which was transiently increased.

Conclusions: Hypofractionated IM-WBRT with a SIB to the tumor bed delivered with TD provides consistent clinical results and it is able to reduce acute skin toxicity rate over conventionally fractionated and sequential boost tomotherapy-based IM-WBRT.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

CyberKnife Prostate SBRT Robert M. Meier, MD; Swedish Cancer Center, Seattle, WA

SBRT should be an ideal approach for organ-confined prostate cancer because 1) dose escalation should yield improved rates of cancer control, 2) the unique radiobiology of prostate cancer favors hypofractionation and 3) the conformal nature of SBRT minimizes high-dose radiation delivery to immediately adjacent organs, potentially reducing complications. Although several external beam platforms are capable of delivering SBRT for early-stage prostate cancer, all of the mature reported series have employed the CyberKnife. These studies report 5-year biochemical relapse rates which compare favorably to IMRT. Rates of late GU toxicity are similar to those seen with IMRT, and rates of late rectal toxicity appear to be less than with IMRT and LDR brachytherapy. Patient-reported quality of life (QOL) in the urinary domain is similar to IMRT and better than LDR brachytherapy. Bowel QOL appears to be less adversely affected by SBRT than with other radiation modalities. With five years of follow-up CyberKnife SBRT results are extremely encouraging. We await longer follow-up of large multi center studies to confirm these outcomes. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

CyberKnife SBRT for Early Stage Lung Cancer and the Impact of Motion on Chest Wall Dosimetry Eric Schreiber, PhD, University of North Carolina

Our institutional experience with CyberKnife stereotactic body radiotherapy (SBRT) for early stage lung cancer suggested a lower rate of chest wall toxicity than generally reported for SBRT (2% rib fracture institutionally vs ≈ 8% elsewhere). Similarly low rates have been reported by other CyberKnife users. We hypothesize that this could be related to the CyberKnife tumor tracking with respiration, in which the dose cloud moves with the lesion, blurring the high dose to the chest wall. In this study, we assessed chest wall dosimetry for: 1) a typical linac-based gated SBRT plan utilizing an ITV expansion, 2) a CyberKnife plan using the same target volume as the linac-based SBRT plan, 3) a CyberKnife plan using Synchrony, and 4) a CyberKnife plan using Synchrony with dose-cloud motion effect included. The results of the motion effect study were compared with a mathematical model. Dose calculations based on breath-hold planning CT scans were found to overestimate the maximum dose to the chest wall if motion effects were not included in the calculation, and suggest that respiratory tracking may have advantages over gating and ITV-based approaches to lung SBRT with respect to normal tissue toxicity.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Safety and efficacy of adjuvant low dose total marrow irradiation in patients with relapsed multiple myeloma. Tessa de Vin1, Karel Fostier², Truus Reynders1, Rik Schots², Guy Storme1 and Mark De Ridder1 1Department of Radiation Oncology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium ²Department of Clinical Hematology, Universitair Ziekenhuis Brussel (UZ Brussel), Brussels, Belgium

Multiple myeloma (MM) is characterized by malignant proliferation of monoclonal plasma cells that induce substantial immunosuppression and several organ dysfunctions. Although MM is a radiosensitive disease, radiotherapy currently is mostly used in a palliative setting to alleviate pain, to treat (impeding) fractures and spinal cord compression. In the 1980s, the use of high-dose total body irradiation (TBI) in MM patients was introduced as a conditioning regimen prior to bone marrow transplantations, but appeared associated with important toxicity (pneumonitis, enteritis, slower hematological recuperation and opportunistic infections). Image-guided helical TomoTherapy is a relatively new radiation technique that is superior to conventional RT with regard to accuracy of patient positioning and possibilities to minimize radiation exposure of the normal tissues. It thereby offers the possibility to safely deliver higher radiation doses to the bone marrow. Whereas the feasibility of various total marrow irradiation (TMI) regimens has already been demonstrated in a clinical setting by Hui et al and Wong et al, we have investigated the clinical and technical feasibility of image-guided TMI using helical TomoTherapy in our own department as well. Physics quality assurance confirmed an expected prescribed dose and dose distribution. A major remark from the technicians, however, was the long lasting time for patient positioning. Therefore, localization of these patients with a scout imaging (2D topogram) mode, either used with or instead of 3D megavoltage computed tomography imaging, is highly desirable as this approach can significantly reduce the patient localization time. In future, in cooperation with the hemato-oncologists in our center, we would like to investigate if low-dose TMI, addressing the microenvironment in MM, has a potential immune-modulating role in these patients. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Practical Image Guided Radiotherapy for Hypofractionated of Upper and Lower Body Total Marrow Irradiation. Vagge S1, Gusinu M2, Agostinelli S2,Pupillo F2, Vidano G1, Corvò R1 1Radiation Oncology Department, 2Medical Physics Department IRCCS San Martino IST National Cancer Research Institute and University, Genoa (IT)

Objectives: Total Marrow Irradiation (TMI) by Helical Tomotherapy (HT) compared with conventional Total Body Irradiation (TBI) allows dose escalation with a normal tissue sparing gain ranging from 35% to 70%. We investigate the importance of a comfortable and reproducible patients setup to maintain limited margins expansion from clinical target volume (CTV) and its impact in clinical practice.

Methods: Patients immobilization system was made up by two carbon fiber base plates (AIO solution, Orfit Industries®) for the upper and the lower part of the body covered by dedicate cushions. An open thermoplastic mask was used to immobilize the head and other two for the upper body and the feet respectively. Considering the whole body skeleton as the CTV, the planning target volume (PTV) was obtained by adding 5 mm isotropic margins to the CTV contoured on two CT simulation scan with different breath phase (inspiration and normal breath). Three daily MVCT scan defined the correct patients setup. In vivo dosimetry with gafchromic films and Mosfet® dosimter was performed to verify the agreement between correction shifts and planning dose over high and low dose region and over the field junction for the lower part of the body. In-vivo dosimetry was even compared with the one replanned on MVCT scans by Tomotherapy adaptive software. The same treatment plans were replanned with different PTV margins to define the variation of the dose to all the organs at risk (OAR).

Results: Between 2011 and 2013 twenty patients with multiple myeloma (MM) and acute myeloid leukemia (AML) have been treated before autologous stem cell transplantation (ASCT). Patients were treated with a hypofractionated schedule of 12Gy in three daily fractions considering the expected lower acute toxicity. The median beam on time for the upper part of the body (till the knees) was 37 min and 10 min for the lower body (from knees to feet). For all the patients the median shifts on all the axes were 3.5 mm and PTV expansion of 5 mm was never overtaken. The correlation of planned, MVCT recalculated and in vivo measured dose never exceed the 5%. The dose to the fields’ junction between upper and lower body verified with gafchromic films showed an agreement with the planned one within the 10%. The median dose to OAR showed an increase from 10% to 20% if the 5 mm PTV margin was enlarged respectively to 10 mm and 15 mm.

Conclusions: TMI by HT is a promising technique that will replace TBI in many onco-hematological diseases. However to take the advantages from this technique a comfortable and precise setup of the patients is needed. The integrated IGRT system allows verifying precisely the delivered dose to minimize PTV margins and limiting OAR doses.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric comparison of Tomotherapy and VMAT in Total Marrow Irradiation Lukasz Matulewicz, Michal Radwan, Leszek Miszczyk, Sebastian Giebel, Krzysztof Slosarek Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice, Poland

Objectives: The goal of this study was to compare Tomotherapy with Volumetric Modulated Arc Therapy (VMAT) for Total Marrow Irradiation (TMI) with regard to the dosimetric quality and efficiency of delivery.

Methods: Fifty patients with multiple myeloma were planned by Tomotherapy (helical and direct technique, 6MV, TomoHD, Accuray, Inc.) and re-planned by VMAT (sixteen arcs, 20MV, Clinac 2300, Varian Inc.). As a target, all skeletal bones were contoured (Eclipse, Varian Inc.) excluding hand bones, jawbone, mandible and ethmoid bone. A 5mm margin was added to the long bones. Critical organs were contoured for conformal avoidance. The optimization goal was to achieve that a minimum of 85% of the target volume receives at least 99% of the prescription dose (12 Gy). Fractionation scheme was 3 x 4 Gy (three consecutive days, one irradiation a day). Plan quality was assessed by calculating conformity index (CI) for the 99% reference isodose and homogeneity index (HI) of PTV, as well as D50% dose of OARs for both techniques. For plan efficiency evaluation, an effective total treatment time (including imaging and positioning) was considered.

Results: For Tomotherapy/VMAT, mean CI was 0.877/0.850 and mean HI was 1.157/1.212. Mean D50% doses to OARs were: lenses 2.18 Gy/3.29 Gy; oral cavity 4.14 Gy/4.19 Gy; kidneys 5.26 Gy/6.35 Gy; bladder 5.44 Gy/6.11 Gy; heart 6.50 Gy/6.39 Gy; bowel 6.57 Gy/7.44 Gy; liver 7.07 Gy/7.58 Gy; brain 7.26 Gy/6.91Gy; lungs 7.32 Gy/8.41 Gy. Mean effective treatment time per fraction was estimated: 92 minutes/103 minutes.

Conclusions: The study disclosed similar dosimetric quality of both techniques for TMI, however, Tomotherapy provided better dose conformity and homogeneity of PTV than VMAT approach. Moreover, Tomotherapy plans revealed generally better OARs sparing except for heart and brain. Finally, complexity of the multi-arc VMAT plans required more time for delivery due to positioning of every isocenter. Transit dosimetry analysis (Mathresolutions, LLC) for the project is ongoing. ORAL CLINICAL ABSTRACTS The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Accuray AERO Users’ Meeting, Minneapolis, May 7 2014 CyberKnife Clinical Scientific Session: Marquette Ballroom I – V Moderator: Clinton A. Medbery, III, M.D., Board of Directors, The Radiosurgery Society

Time Duration Speaker Title

Results of Stereotactic body radiotherapy (SBRT) 1:00 10 min Pierre-Yves Bondiau for management of primary and secondary hepatic tumors: Analysis of early outcomes

Critical analysis and efficacy of Linac based (Beam 1:10 10 min Karrthick KP Modulator) and cyberknife treatment plans for acoustic neuroma/schwannoma

Hyperfractionated Stereotactic Reirradiation for 1:20 10 min David Feltl Recurent Head and Neck cancer

M. Munir Centrally Located Early Stage NSCLC SBRT: 1:30 10 min Muniruzzaman Retrospective Outcome Analysis

Stereotactic body radiation therapy as an adjunct 1:40 10 min Jessica Vernon in the treatment and palliation of gynecologic malignancies

Acute side effects in the first year of Stereotactic 1:50 10 min Judith Huerta-Bahena Radiotherapy and Radiosurgery at a new Radiosurgery Center in Mexico

Mix and match: Combined tomotherapy 2:00 10 min David Roberge and Cyberknife fractionated stereotactic radiotherapy for benign skull base tumors

2:10 15 min All authors Q&A

2:25 10 min Coffee Break The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

TomoTherapy Clinical Scientific Session: Marquette Ballroom I – V Moderator: Patrick Kupelian, MD, Ronald Reagan UCLA Medical Center

Time Duration Speaker Title

A Phase II Pilot Single Arm Prospective Clinical Trial of Rapid Institution of Helical TomoTherapy-based 2:35 10 min Paul Read Radiation Therapy for Patients with Painful Osseous Metastatic Disease

The Use of TomoTherapy for the Treatment of 2:45 10 min Tewfik Bichay Trigeminal Neuralgia

IMRT for Angiosarcoma of the Scalp Using 2:55 10 min Katsuyuki Karasawa TomoTherapy: Planning Study and the Initial Results

Impact of the intra and inter observer variability in the delineation of parotid glands on the 3:05 10 min Adam Ryczkowski dose calculation during head and neck helical tomotherapy

On simple tangential breast treatment with 3:15 10 min Nathan Corradini TomoDirect 3D

Palliative radiotherapy for painful bone metastases 3:25 10 min Pierfrancesco Franco from solid tumors delivered with static ports of tomotherapy (TomoDirect)

Challenging Breast Cancer Cases: Utilization of Tomotherapy IMRT for Comprehensive Concurrent 3:35 10 min Daniel Landis Treatment of the Local-Regional Field Alongside Small Volume Oligometastatic Disease

3:45 15 min All authors Q&A

4:00 End The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Results of Stereotactic body radiotherapy (SBRT) for management of primary and secondary hepatic tumors: Analysis of early outcomes Pierre-Yves Bondiau*, Eman Elalfy, Karen Benezery, Jerome Doyen Laurent Mineur, Eric Teissier, Olivier Thomas, Georges Garnier *Department of Radiotherapy, Centre Antoine Lacassagne, Nice, France

Objectives: To evaluate early outcomes of hepatic tumors treated with robotic SBRT (CyberKnife).

Methods: Between March 2007 and December 2012, 59 patients were treaed: 48 with Hepatic Metastases (HM), 8 with Hepatocellular Carcinoma (HCC), 3 with Cholangiocarcinoma (CC). The CTV margin for HCC and CC was 5 mm, PTV margin 3 mm. No margin was used for HM. Median dose was 47.61 Gy in 3 fractions prescribed to the 80% isodose line.

Results: We report one grade 3 toxicity. For HCC the overall survival (OS) was 41.7% at 1 year, local control (LC): 75% at 1 year. At 1 and 2 years we report, respectively, for HM: OS: 83.6% and 57%, disease-free survival (DFS); 69.5% and 46.1%, LC: 76.3% and 57.9%. For CC; OS: 100% and 50%, DFS and LC: 50% and 0%.

Conclusions: Age, volume of tumor, dose, coverage of target volume are prognostic factors for survival and LC.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Critical analysis and efficacy of Linac based (Beam Modulator) and cyberknife treatment plans for acoustic neuroma/schwannoma. Karrthick.K.P1,2, Vikraman.S1,2, Mohanraj.U1, Karthikeyan.N1,2 ,Senniandavar.V1, Sambasivaselli.R1, Tejinder Kataria1 1) Division of Radiation Oncology, Medanta The Medicity, Gurgaon, Haryana, India. 2) Research and Development, Bharathiar University, Coimbatore, Tamilnadu, India.

Objectives: To study the critical analysis and efficacy of Linac based ( Beam Modulator) and cyberknife treatment plans for acoustic neuroma/schwannoma.

Methods: Twenty patients of acoustic neuroma/schwannoma were taken for this study who underwent radical treatment in cyberknife. All treatment plans were generated in Multiplan treatment planning system (TPS) version 4.6. For each patient target and OAR delineation were conformed by fusing CT images with contrast MRI images. All these patient’s CT images and RT structures were imported into Monaco TPS and linac based stereotactic VMAT plans were generated using Elekta SynergyS Beam Modulator with MLC thickness of 4mm. The size of the target volumes were in the range of 0.280 cc to 9.256 cc. Prescription dose of 1150cGy to 1950cGy were used for the range of 1 to3 fractions. All cyberknife plans were generated using 6D skull tracking methods and fixed collimators of 5, 7.5 and 10mm dia. For linac plans, parameters such as arc length, target dose rate, and minimum segment size were all kept constant. Appropriate calculation algorithms and grid size were used with same prescription dose and OAR constrains for both linac and cyberknife plans. All the plans were developed to achieve at least 95% of the target volume to receive the prescription dose. The dosimetric indices such as conformity index, coverage, OAR dose and volume receiving 50% of the prescribed dose (V50%) were used to evaluate the plans.

Results: For the target volumes ranges from 0.280 cc to 3.5cc shows the mean conformity index with standard deviation of 1.16±0.109 and 1.53±0.360 for cyberknife and linear accelerator plans respectively. For all these small volume tumors the OARs were well spared in the cyberknife plans. There is no significant differences in the conformity index and OAR doses were observed between cyberknife and linear accelerator plans which has the target volume more than 3.5 cc. Perhaps the volume receiving 50% of prescribed dose were lesser in all cyberknife based plans as a results shows the mean and standard deviation of 22.8 ± 15.0 and 12.8± 8.4 for linac and cyberknife respectively.

Conclusions: The acoustic neuroma/schwannoma patients with target volumes greater than 3.5 cc can be treated in linear accelerator as comparable with cyberknife plans. For the small volume targets (<3.5cc) like acoustic neuroma/schwannoma cases the cyberknife plans were shows the superior plan quality with better conformity index and OAR sparing than the linac based plans. Further studies may require to evaluate the clinical benefits of cyberknife robotic system. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Hyperfractionated Stereotactic Reirradiation for Recurrent Head and Neck cancer David Feltl, Jakub Cvek, Lukas Knybel, Bretislav Otahal Department of Oncology, University Hospital Ostrava, Ostrava, Czech Republic

Objectives: To evaluate the feasibility of a hyperfractionated stereotactic reirradiation (re-RT) for inoperable, recurrent head and neck squamous cancer (HNSCC) unsuitable to systemic treatment.

Methods: Nineteen patients with recurrent HNSCC (oral cavity-6, lymph node-5, orofarynx-2, nasal and paranasal sinuses-2, larynx/hypopharynx-2, nasopharynx-1and parotid gland-1) were included in this study. Median gross tumor volume was 65 ml (range 12-193 ml). Primary radiotherapy dose was higher than 60Gy and time gap to the start of re-RT was higher than 9 months. CyberKnife (CK) system with a 6 MeV linear accelerator was used. The treatment plans were non-isocentric (sequential optimization) and non- coplanar with approximately 200 pencil beams. Plans were designed to cover 95% of PTV (GTV + 3 mm for microscopic spreading, no additional set-up margin) with the prescribed dose (48Gy in 16 fractions). Dose per fraction of 3 Gy was administered twice daily with a minimum 6-hour gap. Uninvolved lymphatic nodes were not irradiated.

Results: Treatment schedule was finished as planned for all patients (median duration was 11 days, range 9-14). Median isodose line with prescribed dose was 80 % (range 71-82 %). Median duration of one fraction was 28 min (range 17-52 min). Median conformality index, new conformality index and homogeneity index were 1.21 (range 1.11-1.32), 1.28 (range 1.2-1.41) and 1.24 (range 1.22-1.41) respectively. Median maximal dose to the spinal cord was 9 Gy (range 0-21Gy). On-line image guidance according to the skull base (21 %) or cervical spine (80%) was used for precise set-up, no fiducial markers were used. Acute toxicity was evaluated according to the RTOG/EORTC scale; the incidence of Grade 3 mucositis was 37 % in the oral cavity/pharynx and 0% in the skin and the recovery time was ≤4 weeks for all patients. Late toxicity was evaluated according to the RTOG/EORTC scale. Neither carotid blowout syndrome nor other Grade 3/4 late toxicity were observed. One-year overall survival (OS) was 35%.

Conclusions: Hyperfractionated SBRT is an appealing treatment option for patients with recurrent HNSCC previously irradiated with high doses. Dose level at 48Gy in 16 fractions twice a day is feasible. Acute toxicity was mild; duration of dysphagia or confluent mucositis was less than 4 weeks. No severe late toxicity was observed and more than one third of patients survive more than 1 year.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Centrally Located Early Stage NSCLC SBRT: Retrospective Outcome Analysis M. Munir Muniruzzaman PhD, Ajmel Puthawala MD, Nisar Syed MD, Joel Cherlow MD, Steven Damore MD, Asif Harsolia MD, Linda Chan MD, Bouchaib Rabbani PhD

Objectives: To evaluate side effects, local disease control and outcome of centrally located early stage non small cell lung cancer SBRT using the CyberKnife Robotic Radiosurgery System.

Methods: Hypofractionated lung SBRT has shown excellent outcome. But centrally located lung SBRT can result in adverse side effects, especially respiratory and lung function, if the dose is too high. On the other hand, low dose may result in local failure. Therefore a balancing act has to be made for central lesions. We report here the retrospective analysis of 27 centrally located NSCLC patients treated between 2009 and 2013 at Orange County CyberKnife & Radiation Oncology Center. PET/CT and/or CT in lung window were used to delineate the target and critical structures. The target volumes were tracked in real time during treatment either by Xsight lung tracking or Synchrony motion tracking using gold markers, depending on the location of the tumor. Patients were treated on alternate days instead of standard daily treatment schemes. Patients received 40 to 50 Gy in 5 fractions. In all cases, the dose constraint to the bronchial tree was strictly maintained and the planning target volumes were adjusted to meet the constraints.

Results: All patients tolerated the treatment well. Median follow-up is 12 months. No acute respiratory side effect was reported by the patients. Patient follow-up evaluations included assessments of lung function before and after SBRT as well as pre and post imaging comparison. Two patients showed recurrence just outside of the treatment fields. In other cases good local control of disease were achieved.

Conclusions: Retrospective study of the centrally located NSCLC SBRT with CyberKnife demonstrates that it can be a promising strategy for local control. The excellent tumor tracking mechanism and sub- millimeter targeting accuracy of CyberKnife enables steep dose gradient and thereby allowing to deliver significant dose without compromising the dose tolerance to critical volumes. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Stereotactic body radiation therapy as an adjunct in the treatment and palliation of gynecologic malignancies Jessica Vernon, MD (Chief Resident, Department of Obstetrics and Gynecology, Sinai Hospital of Baltimore), Jeanette Linder, MD (Chief, Division of Radiation Oncology, Sinai Hospital of Baltimore), Cardella Coleman MD (Faculty, Department of Radiation Oncology, Sinai Hospital of Baltimore), Fouad Abbas MD (Chief, Division of Gynecologic Oncology, Sinai Hospital of Baltimore), Mark Miller DO (Faculty, Department of Gynecologic Oncology, Sinai Hospital of Baltimore), Chris D’Adamo PhD (Assistant Professor, University of Maryland School of Medicine), Okey Ibeanu MD (Faculty, Department of Gynecologic Oncology, Sinai Hospital of Baltimore)

Objectives: Oncologists in our institution have utilized stereotactic body radiation therapy (SBRT) since 2003 in the treatment and palliation of gynecologic malignancies. The goal of this initial report is to describe the patient population in which SBRT is used and analyze patient outcomes for both primary therapeutic and palliative treatment intents in the recurrent diagnosis setting.

Methods: An IRB approved retrospective review was performed for all patients who received SBRT at our facility for a primary gynecologic malignancy between 2003-2013.

Results: 68 gynecologic cases were recorded. Prevalent primary carcinomas were ovarian (32.8%), cervical (22.4%), and endometrial (22.4%). Tumor histologies were 20% adenocarcinoma, 15.6% squamous cell, 14.1% each serous endometrial and leiomyosarcoma. 70% had stage 4 diagnosis, 71% had recurrent disease, and 68% had a solitary lesion. All of the patients had received prior treatment; chemotherapy (80%), radiation (68%), and surgery (79%). Majority of the patients were white (70.8%). Over half (53.7%) of patients had diagnosed comorbidities. Patient population had an average BMI 27.3, albumin 3.7, and hemoglobin 11.2. Mean age at diagnosis was 55.6 years and mean age at time of SBRT treatment was 59.2, with a mean time from diagnosis to SBRT of 44.4 months. 63% received therapeutic intent SBRT and 37% received palliative SBRT treatment. For therapeutic intentions (n 41) the average time from treatment to recurrence was 10.8 months and average treatment -free survival was 12.1 months. Average post-treatment survival was 18.2 months and average overall survival 60.5 months. Of the patients receiving palliative treatment (n 24), 17 were symptomatic prior to treatment and 14 of those had symptomatic relief (82%).

Conclusions: SBRT has been used in our institution as a therapeutic adjunct in the treatment of recurrent gynecologic malignancies. Most patients had advanced stage disease at time of diagnosis but experienced a prolonged latency period between initial diagnosis and primary treatment and subsequent SBRT therapy. Our patients receiving therapeutic SBRT had an average treatment-free period of 12 months and post- SBRT treatment survival of 18 months. SBRT merits wider evaluation as an adjunct to conventional therapy in this patient sub-population.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Acute side effects in the first year of Stereotactic Radiotherapy and Radiosurgery at a new Radiosurgery Center in Mexico. Judith Huerta-Bahena, M.D.,* Armando Félix, M.D.,* Alberto Pérez, M.D.,° Adan Agreda, M.D., ° Gerardo Gutiérrez PH.D.,^ and Angel Calva M.D.* Departments of Radiation Oncology*, Physics^ and Neurosurgery°, Oncology Hospital, National Medical Center, Mexico City.

Objectives: For the first time in Mexico’s social security system, on July 2012 the Robotic Radiotherapy Unit at Centro Médico Nacional SXXI in Mexico City began treatments of both intracranial stereotactic radiotherapy and stereotactic body radiotherapy using the CyberKnife system (Accuray Incorporated, Sunnyvale, California, USA). The following is our report of the acute effects that patients treated within the first year of experience presented.

Methods: We analyzed the records of 132 consecutive patients with intracranial and extracranial lesions, who were treated on a robotic non-isocentric dedicated SBRT/SRS linac (CyberKnife system Accuray Incorporated, Sunnyvale, California, USA) between July 2012 and June 2013. Intracranial SRS/SRT was administered to 81 patients with 83 targets, whereas 51 patients received SBRT to 57 targets. During the patients’ treatment and within the two weeks that followed, we evaluated the acute morbidity associated. Any new and unexpected symptom occurring within the 6 weeks after the treatment were also evaluated and scored according to the RTOG scale for acute toxicity. Treatment and pretreatment variables that might influence the occurrence of acute morbidity were also analyzed.

Results: In the group of patients with intracranial lesions the most frequent tumor treated was Pituitary Adenoma followed by Meningioma, Metastases and Acoustic Neuroma. Sixty-nine percent of patients coursed completely asymptomatic. The most frequent G1 side effect was dizziness/vertigo (8 cases), headache (4 cases), one patient presented hypotension and tiredness, and three patients described a combination of all the symptoms. Grade 2 acute side effects were present in 6 of the 23 patients. One patient with a history of seizures required hospitalization due to an increase of the episodes; he was hospitalized only for a day. Out of the 81 patients, 46 did not report having any side effects, or reported side effects that were so mild that didn’t require any medical treatment. We provided 35 patients with a prophylactic treatment to prevent brain edema 21 of which didn’t have any side effects. During the same period, we treated 51 patients with 57 extracranial lesions. Most of them had Prostate cancer (37 cases) and the rest had been diagnosed with ganglionar oligometastases or with primary or metastatic lung or hepatic tumors. Forty-four percent of the patients coursed completely asymptomatic. We provided 12 symptomatic treatments, most of which were required by patients with Prostate cancer. Out of the 32 patients with morbidity, 12 reported Grade 2 side effects. There were no patients with Grade 3 or higher acute morbidity.

Conclusions: The levels of acute morbidity found within our first year of experience using Stereotactic Radiotherapy and Radiosurgery for both intracranial and extracranial lesions confirm the safety of this treatment. We have observed that any acute morbidity derived from this treatment is mild and easily manageable. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Mix and match: Combined tomotherapy and Cyberknife fractionated stereotactic radiotherapy for benign skull base tumors. Ibrahim Atean (Department of radiation oncology, CHUM - Notre Dame) Dominic Béliveau-Nadeau (Department of medical physics, CHUM - Notre Dame) Jean-Paul Bahary (Department of radiation oncology, CHUM - Notre Dame) David Roberge (Department of radiation oncology, CHUM - Notre Dame)

Objectives: Although Cyberknife radiotherapy is uniquely accurate, conformal and focused, its use in protracted, conventionally fractionated radiotherapy can be limited by resource scarcity or concerns regarding potential for marginal miss du to steep gradients and tight margins. We aimed to review our experience combining more conventional intensity modulated radiotherapy (IMRT) with Cyberknife radiotherapy.

Methods: We retrospectively reviewed all cases of benign intracranial tumors treated with combined Cyberknife and IMRT conventionally fractionated radiotherapy at our institution. Statistical significance of differences between Cyberknife and conventional plans was tested using paired t-tests.

Results: We identified 13 patients treated from December 2011 to December 2013. The diagnoses were meningioma (38%), pituitary adenoma (23%), craniopharyngioma (23%) and schwannoma (15%). All patients received a total of 9Gy in 5 fractions using the Cyberknife following 41.8-50.4Gy of conventional IMRT for a total dose of 50. 4-54Gy in 1.8Gy fractions. The conventional IMRT was delivered using image-guided helical tomotherapy in 38% and either volumetric of fixed-beam IMRT in the other 62%. A 2mm PTV margin was used for conventional IMRT and no PTV margin was used for the Cyberknife fractions. In 9 patients, the dose-limiting OAR was the optic chiasm. In these patients the minimum PTV dose was on average 1.5% higher than the maximum dose to the chiasm. While it was 4% lower in IMRT, p=NS. Without excess dose to OARs, the median dose to the PTV was higher in the CK plans 116% vs. 101% (p<0.001). With a median of 1 collimator, 90 fields and 1461MU per fraction, the estimated median time to deliver a Cyberknife fraction was 17 min (range: 10 to 30). The treatments were all acutely well tolerated and, within the limitations of the short follow-up, no tumor has progressed.

Conclusions: A 9Gy conventional boost was easily integrated into regimen of radiotherapy for base of skull tumors unsuitable to single fraction radiosurgery with reasonable treatment times. Dosimetric gains were modest and the treatments were acutely well tolerated.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

A Phase II Pilot Single Arm Prospective Clinical Trial of Rapid Institution of Helical TomoTherapy-based Radiation Therapy for Patients with Painful Osseous Metastatic Disease David Wilson, UVA Dept. of Radiation Oncology: Clayton Alonso, UVA School of Medicine: Austin Sim, UVA School of Medicine: Lydia Levinson Handsfield, UVA Dept. of Radiation Oncology: Quan Chen, UVA Dept. of Radiation Oncology: Leslie Blackhall, UVA Dept. of Internal Medicine: Paul Read, UVA Dept. of Radiation Oncology

Objectives: To evaluate the efficacy and patient satisfaction of the STAT-RAD workflow, a workflow that delivers highly conformal, hypofractioned palliative radiotherapy to painful bone metastases while compressing the standard workflow into 6 hours, allowing for simulation, planning and treatment to take place on the same day.

Methods: Patients with 1-3 painful bony metastases were prospectively enrolled. Patients were treated with 2-5 fractions with a dose of 5-10 Gy per fraction according to the STAT-RAD workflow using the TomoTherapy treatment unit. Treatment planning was expedited on the VoLO treatment system with most patients being treated with TomoHelical and TomoDirect 3D plans. Quality Assurance was performed with routine phantom measurements prior to treatment and with a novel QA workflow we call MC Dose Calc + Log file QA in which TomoTherapy plans undergo an independent monte carlo dose calculation prior to treatment for QA of the calculations and log file analysis of the leaf opening time for QA of the treatment delivery. Patients were evaluated for pain, opioid use, satisfaction, performance status, and quality of life prior to treatment and at 1, 4, 8, 12, 26, and 52 weeks post treatment.

Results: Nineteen patients were enrolled and treated with the STAT-RAD workflow. Patients received an average of 22.7 Gy over 2.9 fractions. Average worst pain scores were significantly lower at all post- treatment time points compared to pretreatment. Opioid use was not found to be significantly different from baseline at any point. Performance status according to the Karnofsky Performance Status scale was found to be significantly increased at the 4 week time point, however, there was no significant change in performance status at the other time points. Quality of life according to the FACT-BP was significantly increased at all time-points. Quality of life according to the FACT-G was significantly increased at only the 4 and 8 week time points. All patients reported being mostly or completely satisfied with the treatment results by the 8th week post-treatment.

Conclusions: Our preliminary results demonstrate that treating bone metastases with highly conformal, hypofractionated radiation therapy according to the STAT-RAD workflow results in a significant and durable improvement in pain and quality of life. Though, performance status and opioid use were not found to be significantly altered, patient satisfaction was high with this same-day treatment workflow. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

The Use of TomoTherapy for the Treatment of Trigeminal Neuralgia Tewfik J Bichay, PhD1,2, C Michael Wilkinson, MD1, Jamie Kokko, MPH1, James Kane, MD1, Gilbert DA Padula, MD1 1Mercy Health Lacks Cancer Center, Grand Rapids, Michigan, USA, 2Wayne State University School of Medicine, Detroit, Michigan, USA

Objectives: Trigeminal neuralgia (TGN or tic douloureux) is a chronic and episodic syndrome involving one or more of the three branches of the fifth cranial nerve. In this paper we present the clinical outcomes of the first use of TomoTherapy for the treatment of TGN.

Methods: Nine patients were treated using the 1 cm mode of TomoTherapy to doses of 30 Gy-35 Gy to the trigeminal nerve plus margin. Imaging for patient positioning was carried out using a 1 mm MVCT slice thickness mode developed on TomoTherapy for this purpose. The patients were treated at our facility from 2007-2012. We conducted a retrospective chart review and a follow up phone survey of treated patients summarizing demographic, clinical, treatment, and outcome information.

Results: Of the 9 patients with TGN treated using TomoTherapy 89% were female, and 11% of patients had a history of multiple sclerosis. Twenty-two percent were affected on V2 only, 33% on V3 only, 11% on V2+V3, 11% on V1+V2+V3, and in 22% of patients the trigeminal nerve distribution was not recorded. Fifty-six percent of patients were affected on the left side of the body, 33% on the right and 11% were affected bilaterally. All patients were treated on one side of the body (56% left, 44% right). All patients had at least one follow up appointment after treatment. The mean overall pain score recorded prior to treatment was 6.6 out of 10 (0=no pain, 10= worst pain) (n=8) and 1.7 out of 10 (n=6) at the first follow up visit.

Conclusions: Patients treated on this protocol experienced a reduction in TGN pain and reported favorable outcomes of treatment after TomoTherapy radiosurgery. These results suggest that TomoTherapy can be used to treat TGN when other forms of radiosurgery are not easily available. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

IMRT for Angiosarcoma of the Scalp Using TomoTherapy: Planning Study and the Initial Results Katsuyuki Karasawa, Shun’ichiro Kageyama, Satoshi Kitou, Koji Yoshino*, Yukiko Shibata, Kei Ito, Hiroto Murata, Takuya Shimizuguchi, Hiroshi Tanaka, Yumiko Machitori, Keiji Nihei, Motoaki Fujii, Hikari Kobayashi*, Tomoaki Okano, Shimpei Hashimoto, Tomohisa Furuya Department of Radiology, Dermatology*, Tokyo Metropolitan Komagome Hospital

Objectives: Angiosarcoma of the scalp is relatively rare disease and affects mainly elderly patients. It is very difficult to control primary tumor as well as distant metastases. The mainstay of the treatment is surgical resection combined with chemoradiotherapy (CRT). However, it often progresses rapidly and becomes unresectable at the initial presentation. Thus we often treat this disease with definitive CRT. Conventional photon beam treatment would have irradiated underlying normal brain tissue, thus not suitable for treatment. Therefore, we used electron beams of certain energy. However, it is quite difficult to irradiate the targets homogenously lying on the surface of spheres by any shape of cone of the electron beam for fear of overlapping of the fields. TomoTherapy, on the other hand, has known to be capable of hollowing out such kind of normal tissue and thus we used it for the treatment of this disease since 2013. In this study, dose distributions by TomoTherapy and by Segmental MLC-IMRT(SMLC-IMRT) in 3 cases were compared and their clinical responses treated by TomoTherapy were evaluated.

Methods: Initial clinical target volume (CTV1) was set to be gross tumor volume (GTV) and suspected involved areas such as purpura and edema plus 2 to 3 cm margin. Cone down CTV (CTV2) was set to be GTV and suspected involved areas plus appropriate margin decided by Dermatologist. PTV margin was set to be 0.5 cm for both targets (PTV1 and PTV2). We irradiate 60 Gy / 30 fractions to the PTV1 with the 10 Gy / 5 fractions of boost to the PTV2. Concurrent chemotherapy was given with weekly paclitaxel (PTX) at the dose of 60 mg/m2. Following the completion of concurrent CRT, weekly PTX at the dose of 60 mg/m2 was given until progression.

Results: So far, we treated 4 patients. Among them, we compared the dose distributions between TomoTherapy and SMLC-IMRT in 3 cases. Average of the maximum, mean, and minimum PTV2 doses were, 78.0 +/- 1.6 Gy, 69.6 +/- 0.8 Gy, and 46.0 +/- 4.4 Gy, respectively for TomoTherapy, and 83.5 +/- 1.6 Gy, 69.5 +/- 1.0 Gy, and 23.2 +/- 9.1 Gy, respectively, for SMLC-IMRT. As for minimum PTV2 dose was significantly higher for TomoTherapy (p=0.0175). Regarding normal tissue dose, the average of maximum and mean cerebral doses were 68.3 +/- 1.9 Gy, and 20.9 +/- 6.8 Gy, respectively for TomoTherapy and 73.6 +/- 5.3 Gy, and 27.1 Gy +/- 11.4 Gy, respectively for SMLC-IMRT. As for clinical response, there were 1 CR and 3 PRs. No local or distant relapse has been observed. There was 1 grade 3 acute neurotoxicity complicated by bacterial septic shock and 1 grade 2 skin toxicity.

Conclusions: TomoTherapy provided more homogenous PTV dose compared with SMLC-IMRT. Our initial results were promising with acceptable toxicities. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Impact of the intra and inter observer variability in the delineation of parotid glands on the dose calculation during head and neck helical tomotherapy T. Piotrowski [1,3], K. Gintowt [3], A. Jodda [1], A. Ryczkowski [1], W. Bandyk [1], B. Bąk [2], M. Adamczyk [1], M. Skorska [1], J. Kazmierska [2,3], J. Malicki [1,3] [1]Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland; [2] 2nd Radiotherapy Department, Greater Poland Cancer Centre, Poznan, Poland; [3] Department of Electroradiology, University of Medical Sciences, Poznan, Poland

Objectives: The intra- and inter-observer variability in delineation of the parotids on the kilo-voltage computed tomography (kVCT) and mega-voltage computed tomography (MVCT) were examined to establish their impact on the dose calculation during adaptive head and neck helical tomotherapy (HT).

Methods: Three observers delineated left and right parotids for ten randomly selected patients with oropharynx cancer treated on HT. The pre-treatment kVCT and the MVCT from the first fraction of irradiation were selected to delineation. The delineation procedure was repeated three times by each observer. The parotids were delineated according to the institutional protocol. The analyses included intra- observer reproducibility and inter-structure, -observer and -modality variability of the volume and dose.

Results: The differences between the left and right parotid outlines were not statistically significant (p>0.3). The reproducibility of the delineation was confirmed for each observer on the kVCT (p>0.2) and on the MVCT (p>0.1). The inter-observer variability of the outlines was significant (p<0.001) as well as the inter- modality variability (p<0.006). The parotids delineated on the MVCT were 10% smaller than on the kVCT. The inter-observer variability of the parotids delineation did not affect the average dose (p=0.096 on the kVCT and p=0.176 on the MVCT). The dose calculated on the MVCT was higher by 3.3% than dose from the kVCT (p=0.009).

Conclusions: Usage of the institutional protocols for the parotids delineation reduces intra-observer variability and increases reproducibility of the outlines. These protocols do not eliminate delineation differences between the observers, but these differences are not clinically significant and do not affect average doses in the parotids. The volumes of the parotids delineated on the MVCT are smaller than on the kVCT, which affects the differences in the calculated doses. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

On simple tangential breast treatment with TomoDirect 3D Mauricio Leick (1), Nathan Corradini (1), Charles Geraghty (2) (1) Clinica Luganese, Centro di Radioterapia, Lugano, Switzerland (2) Anne Arundel Medical Center, Annapolis, Maryland

Objectives: To evaluate the TomoDirect 3D modality for simple tangential breast treatments on TomoTherapy version 5.0

Methods: A retrospective dosimetric planning comparison was performed on a group of 100 patients for treatment of the whole breast. The patient population was selected to exclude supraclavicular, axillar, and internal mammary involvement, thereby focusing the study on simple breast treatments. A dose of 2 Gy/ fx for a total of 50 Gy was prescribed to the whole breast. Two tangential fields were used in all treatment plans. Patients were planned on TomoTherapy version 5.0 using TomoDirect 3D and TomoDirect IMRT modalities. All TomoTherapy plans used the 5.0 cm field width in dynamic delivery mode with a pitch of 0.5. Patients were also planned on Eclipse version 10 using FinF forward planning. Finally, all patient plans for the three delivery techniques were compared using established dosimetric criteria.

Results: Dosimetric data for the TomoDirect 3D and TomoDirect IMRT plans has been analyzed for 61 patients. Data will be presented showing whole breast dose coverage is similar for both modalities while organ-at-risk sparing is slightly better for TomoDirect IMRT. TomoDirect 3D provided better coverage of the whole breast and similar organ-at-risk sparing when compared to the FinF technique. It was observed that 53 of 61 (87%) of the TomoDirect 3D plans met the dosimetric criteria for clinical acceptance. Ipsilateral lung dose was the largest reason for TomoDirect 3D plans not meeting clinical acceptance criteria.

Conclusions: TomoDirect 3D provides very good coverage of the target while also adequately sparing organs-at-risk for the majority of simple breast treatments. Plans not meeting clinical acceptance criteria are mainly due to disadvantageous curvature of the chestwall requiring excessive irradiation of the ipsilateral lung. Such cases require more modulation than the TomoDirect 3D modality permits. Tangential TomoDirect IMRT plans were able to meet clinically acceptable criteria for these cases. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Palliative radiotherapy for painful bone metastases from solid tumors delivered with static ports of tomotherapy (TomoDirect) Pierfrancesco Franco1 • Fernanda Migliaccio1 • Andrea Peruzzo Cornetto2 • Domenico Cante1 • Piera Sciacero1 •Valeria Casanova Borca2 • Paolo Torielli1 • Michele Zeverino2 • Luigi Lacchio1 • Cecilia Arrichiello2 •Giuseppe Girelli1 • Maria Rosa La Porta1 •Santi Tofani2 • Gianmauro Numico3 • Umberto Ricardi 4 1Radiation Oncology Department - Tomotherapy Unit 2Medical Physics Department 3Medical Oncology Department, AUSL Valle d’Aosta, Aosta, Italy 4Department of Oncology, Radiation Oncology, University of Torino, Turin, Italy

Objectives: To evaluate the response to palliative radiotherapy delivered with TomoDirect (TD) in patients affected with painful bone metastases from solid tumors

Methods: A total of 130 patients (185 osseous lesions) were treated between 2010 and 2013 with TD. Three fractionation schedules were employed according to clinical decision-making (3 Gy x 10; 4 Gy x 5; 8 Gy x 1). Pain response was investigated at 2 weeks and 2 months (for evaluable patients). The Numeric Rating Scale (NRS-11) was used to assess pain. Response rates to radiotherapy were calculated following the criteria of the International Bone Metastases Consensus Group (IBMCG), accounting for the use of concomitant analgesics (response: complete or partial; non-response: stable pain, pain progression or ‘other’). Analgesic consumption was recalculated into the daily oral morphine-equivalent dose (OMED).

Results: Most of the patients had 1-2 bone metastases (91); those with multiple lesions mostly had a metachronous presentation (60%). Synchronous lesions were mainly approached with multiple plans (63%). Most treatments employed 3-4 fields (77%). Treatment times ranged from 255 to 939 seconds depending on fractionation, fields and target lesions number. At 2 weeks, the median self-reported worst pain decreased significantly as median oral morphine-equivalent dose regardless of fractionation used. The response rate according to the IBMCG-based response categories ranged from 45–55%. Pain relief duration seems (response at 2 months) slightly inferior with the single fraction approach, with a higher re-treatment rate.

Conclusions: TomoDirect is a valid option to deliver palliative radiotherapy for painful bone metastases from solid tumors. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Challenging Breast Cancer Cases: Utilization of Tomotherapy IMRT for Comprehensive Concurrent Treatment of the Local-Regional Field Alongside Small Volume Oligometastatic Disease Daniel M. Landis, M.D., Ph.D., John Hatton, CMD Swedish Cancer Institute, Seattle WA

Objectives: To describe the use of helical Tomotherapy in extremely complex cases of advanced breast cancer in which a thoracic metastatic site was included in treatment concurrent with a comprehensive local-regional field.

Methods: Four patients were referred to our center specifically due to the ability of Tomotherapy to concurrently deliver treatment to the local regional bilateral lungs, heart, PTV, and spinal cord. Traditional dose-volume constraints were utilized for clinical acceptability. All patients were treated with helical IMRT utilizing a fixed 2.5 cm jaw. Bolus was not used.

Results: Treatment planning parameters for four complex patients will be described in detail. In three cases, the comprehensive chest wall, axilla, and supraclavicular region +/- internal mammary lymph nodes were safely treated concurrently with one metastatic site (T3, T6, contralateral 3rd rib). In these cases, the constraints for normal lung volume were well within the accepted standard for regional breast radiation alone. The ipsilateral lung V20 ranged from 20-25%, and the ipsilateral lung V5 from 45-53%. The contralateral lung V20 ranged from 2-5% and contralateral lung V5 from 20-25%. The heart V25 ranged from 0-10%. With a median follow up of 12 months (Range 4 to 27 months), two patients are alive without disease. One patient died of distant metastatic disease 13 months after her original diagnosis and 7 months after completion of radiotherapy, without evidence of local failure. In the fourth case, a 40 year old patient was treated comprehensively to the left chest wall, supraclavicular fossa, axilla, ipsilateral internal mammary chain, left mediastinum and left hilum. This included all areas of known metastatic disease. Ipsilateral lung V20 was 41%, V5 69%. The contralateral V 20 was 2%, V5 31%. Bilateral V20 was 20%, and V5 52%. Treatment time was 10.7 minutes with a 2.5 cm fixed jaw. This patient is alive without evidence of progression at 30 months. All patients tolerated treatment well with expected acute effects and only minimal treatment breaks for skin desquamation. One patient developed radiation pneumonitis, which resolved with steroid treatment. No other significant late effects of radiotherapy have been observed.

Conclusions: In the past, technical limitations of radiation treatment delivery precluded the ability to treat patients with oligometastatic breast cancer concurrently with a local-regional field. With the advanced treatment delivery possible from highly modulated helical Tomotherapy, it is clinical feasible to treat the entire local regional breast or chest wall, axilla, internal mammary chain, and supraclavicular fossa while adding additional thoracic disease sites. In these cases traditional dose/volume constraints were able to be maintained which translated to excellent clinical outcomes. For the patients with disease in the T-spine and rib, we were able to maintain standard constraints for lung V20 and V5. In the advanced case that included hilar and mediastinal disease, the dose/volume constraints were well within tolerance range to those typically used in the treatment of stage III lung cancer. ORAL PHYSICS ABSTRACTS The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Accuray AERO Users’ Meeting, Minneapolis, May 7 2014 TomoTherapy Physics Scientific Session: Minneapolis G Moderator: Tewfik J. Bichay, PhD, Mercy Health Saint Mary’s

Time Duration Speaker Title

Comparison of Dynamic Jaw (TomoEdge) versus 1:00 10 min Daniel Landis Fixed Jaw in the Helical-3D Treatment of the Breast Lumpectomy Cavity Boost

Optimization of treatment planning parameters in 1:10 10 min Reena Phurailatpam Tomotherapy for breast cancer patients

1:20 10 min Frederik Crop Breast planning - the skin and robustness issue

Improved dosimetric quality and delivery efficiency 1:30 10 min John Abraham using TomoEdge Dynamic Jaws

Assessment of Anatomic and Dosimetric Variations 1:40 10 min X. Sharon Qi for Head-and-Neck Radiotherapy via A GPU-based Deformable Image Registration framework

Improvement of megavoltage topogram registration 1:50 10 min Benjamin White for patient localization in TomoTherapy

UW Experience Commissioning 2x TomoHDA 2:00 10 min Mark Geurts Systems

2:10 15 min Rick Vaden TomoTherapy Tips and Tricks

2:25 10 min Coffee Break The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

CyberKnife Physics Scientific Session: Minneapolis G Moderator: Mary Ellen Masterson-McGary, CyberKnife Center Of Tampa Bay

Time Duration Speaker Title

2:35 10 min Jimm Grimm Twenty Years of SBRT Clinical Outcomes

Dosimetric evaluation of accelerated partial breast 2:45 10 min Erwann Rault irradiation using the Cyberknife

Multi-Institutional Retrospective Analysis of Gold 2:55 10 min Oliver Blanck Anchor Fiducial Implantation and Tracking for Robotic Radiosurgery

Intelligent margins for SBRT based on tracking 3:05 10 min Pavel Dvorak fiducials

The Method of improving DRR contrast of 3:15 10 min Yang Dong Cyberknife by generating dual-energy CT image dataset from single-energy CT image dataset

A novel end-to-end test system in assessing the 3:25 10 min Lei Wang beam-by-beam delivery accuracy for Cyberknife system

Patient-Specific QA for CyberKnife Plans Using 2D 3:35 10 min Sebastian Adamczyk Ion Chamber Array

3:45 15 min Kari Cann CyberKnife Tips and Tricks

4:00 End The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Comparison of Dynamic Jaw (TomoEdge) versus Fixed Jaw in the Helical-3D Treatment of the Breast Lumpectomy Cavity Boost Daniel M. Landis, M.D., Ph.D. John Hatton, C.M.D. Swedish Cancer Institute, Seattle WA 98107

Objectives: To evaluate PTV coverage, conformity index, time to treat, and dose to organs at risk for breast cavity boost volumes treated with the TomoEdge dynamic jaw.

Methods: In our freestanding tomotherapy-only clinic, many patients with early stage breast cancer are treated with TomoDirect tangential radiation. In these cases typically a helical 3D lumpectomy boost is delivered, as IMRT is not either clinically indicated or is not approved by patient insurance. The goal of the helical boost plan is to cover the lumpectomy cavity while avoiding low-dose scatter to adjacent organs, and to minimize additional irradiation to the breast PTV outside the boost volume. Ten consecutive patients were planned with our standard tomotherapy fixed jaw treatment algorithm and then again using the dynamic jaw with TomoEdge. The most favorable plan was utilized for clinical delivery. The conformality index (CI) was calculated as the ratio of the PTV to the total volume irradiated to the prescription dose (D100). V2, V3, V4, V5 of the ipsilateral lung was determined for each case, as well as mean dose to the contralateral breast.

Results: Ten cases were comparatively planned. The average boost PTV was 94 +/- 33 mL. In all cases, the Dynamic Jaw (TomoEdge) allowed for the jaw size to increase from 2.5 cm to 5 cm with only a very a slight loss of conformality (CI 0.76 vs. 0.69, p=0.03). Although the D100 increased from 103 to 126 mL with the 5cm TomoEdge dynamic jaw, the lung V5 remained unchanged (V5 = 4.9 vs 4.8, p=NS). Additional lung measures such as V2, V3, V4 were similarly not significantly changed. Contralateral cumulative breast scatter dose was not significantly different between the techniques (21cGy vs 15cGy, p=0.2). The beam-on time was decreased significantly from an average of 5.5 minutes to3.8 minutes (p < 0.01). This represented a 30% reduction in treatment time.

Conclusions: The TomoEdge dynamic jaw allowed for significant time savings in the delivery of the helical 3D lumpectomy cavity without compromising nearby organ scatter. Although there was a small statistically significant decrease in conformality index, this was not felt to a significant clinical difference. The lung V5 (and all lung parameters ) and contralateral breast scatter were unchanged between the two approaches. This was largely because the slightly lower conformality of the 5cm jaw at the axial levels corresponding to the PTV volume was offset by the decreased scatter above and below the PTV with the sharper superior and inferior edge delivered by the dynamic jaw. This led to less low-dose scatter above and below the PTV volume with the TomoEdge.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Optimization of treatment planning parameters in Tomotherapy for breast cancer patients Reena Phurailatpam, Siji N.P, Tabassum W, Nara Moirangthem, Priyanka Agarwal, and Rajiv Sarin Radiation Oncology Department, ACTREC, TMC, Kharghar, Navi Mumbai

Objectives: To study the effect of various planning parameters viz field width (FW), pitch factor (PF) and modulation factor (MF) on an off axis tumor and evaluate the relation among these parameters and their influence on the quality of plan and the treatment time.

Methods: Ten patients of breast cancer (five right and five left sided) were taken for the study. The prescribed dose to the boost volume was 61Gy while the dose to the PTV breast was 50Gy in 25 fractions. For each patient, nine plans were created taking various combinations of field width and pitch keeping the Modulation factor constant 3. The possible field width for tomotherapy include 1, 2.5 and 5cm.The pitch was selected as 0.215, 0.287 and 0.43 derived from the optimum pitch value defined as 0.86/n where n is an integer. The reference plan selected for the study is field width of 1, pitch 0.215. Other plans were created keeping the same constraints and penalty as the reference plan and 1000 iterations. Target coverage was evaluated in terms of conformity index (COIN) and homogeneity index (HI) while the sparing of organs at risk (OARs) were evaluated in terms of mean, maximum and relevant dose volumes. Low dose spillage of 5, 10, 20 and 25 Gy in normal tissues were also evaluated. Plans were evaluated for better or worse criteria on the basis that COIN and HI should be greater than their mean value. To compare the plans qualitatively with respect to the reference plan, a parameter called plan quality index (PQI) for organs at risk was generated. If the differences in the PQI were within 10%, it was assumed that there is no significant difference in the plans from the reference plan.

Results: The mean treatment delivery time for the 5, 2.5- and 1.0-cm FW plans were 5.04 ± 0.4, 8.51± 0.87 and 20.67 ± 2.02 minutes respectively. All plans of 1 cm and 2.5 cm FW were in better criteria, except 2.5_ 0.43. But all plans with 5 cm FW were in worst criteria. Ipsilateral lung: For Dmean, there was no significant difference in all plans with 1, 2.5 and 5 cm FW except 5cm_0.43 and no significant variation in the Dmax for all plans. But for V20 values, plans 5cm FW showed significantly higher value. Contralateral lung: No significant variation in Dmean for all plans but for Dmax, all plans with 5cm FW showed significantly higher value. Heart: There was no significant variation in Dmean and Dmax for all plans. But for V13 only one plan 5cm_0.43 showed significantly higher value. Contralateral breast: For Dmean , there was no significant difference in all plans with 1 and 2.5 cm FW except 5 cm FW. For Dmax, no significant difference in all the plans except 5cm_0.43 .But for V2.5 only 1cm FW was not significant but the plans with 2.5 and 5 cm were significantly higher. Low dose spillage: For plan 1cm FW plans there was no significant increase in spillage. For plans 2.5 and 5 cm FW, spillage was increased to 9-14% and 23-47% respectively.

Conclusions: There was a significant difference in the treatment time among the different Field width plans but for a particular FW plan with different pitch, there was no significant difference in the treatment time. Dose to the OARs were not significantly higher for 2.5_FW plans from the reference plan but, significantly higher for 5_ FW. Larger the FW and higher the pitch, spillage were more. From the above study, it can be concluded that 2.5_0.215 plan should be the preferred plan. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Breast planning - the skin and robustness issue Frederik Crop (1), R Heckel (1), D. Pasquier (2), E. Lartigau (2) and N. Reynaert (1) (1) Medical physics and Université Lille (2) Department of radiation therapy and Université Lille

Objectives: We investigated the result of different PTV skin retraction limits on (1) skin dose, (2) the ro- bustness of the CTV coverage during breathing and (3) robustness when optimizing on the skin. The plans were compared with classical treatments: what do we deliver normally during classical treatments, having inherent skin sparing due to buildup.Tomo breast treatments can be performed in static or helical mode, during which the patient breathes freely. For helical mode, there is no addition of “skin flash”, which could lead to underdosage during breathing. On the other hand, when the PTV region is too close to the skin, a high fluence zone could be created in air, just next to the skin leading to an over dosage during respiration.

Methods: A breast case was planned (25x2Gy, whole breast) for Tomo helical treatment and classical treatment (6MV tangential fields, Clinac). PTVs with 5 mm margin around the CTV were created, but with skin sparing retraction between 0 and 5 mm. The skin was created as a 3 mm inner margin and tested as optimization structure. CTV’s with 3 mm and 5 mm skin retraction were evaluated. Breathing was simulated by recalculating the dose distribution on the CT, with movements up to 8 mm in the breathing direction. Final dose was calculated as the weighted sum of a breathing cycle.

Results: 0 mm skin retraction of the PTV volume can not only put a lot of dose on the skin, but also high fluence in the air next to the skin. During breathing this can lead to even higher doses for the skin. As soon as 1 mm retraction is taken, this additional air fluence effect is removed. Tomo mean skin doses are higher than classical treatments (due to the absence of flattening filter, the spectrum is “softer”). Classical treat- ments result in lower mean skin dose (Dmean 34.1 Gy, Dnear-max 48.3 Gy) and a robust treatment. The classical inherent skin sparing build-up effect has as consequence that a CTV with 3 mm skin retraction does not have 95% coverage. For helical Tomo plans, when keeping at least 95% CTV volume covered after breathing, optimization on skin structures leads to the best skin dose (Dnear max 48.3 Gy and Dmean 42.8 Gy, after breathing and using PTV skin retraction of 3mm), but this requires a treatment plan with above normal coverage to compensate for breathing (non robust plan). The best compromise between robustness and skin dose (approaching classical treatments) for CTV with 5 mm skin retraction was found by using a PTV skin retraction of 5 mm, without optimization on a skin structure. However, this still leads to a higher mean dose to the skin, compared with classical treatments.

Conclusions: Both CTV and PTV definition have an important result on the robustness vs skin dose for helical breast Tomo treatments. Classical tangential fields always spare the skin inherently. For Tomo, a compromise has to be made between skin dose and robustness. CTV definition is thus more important for Tomo: what do we really want to be irradiated?

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Improved dosimetric quality and delivery efficiency using TomoEdge Dynamic Jaws John B.S. Abraham, Daniel A. Low, John J. DeMarco, X. Sharon Qi Department of Radiation Oncology, David of Geffen School of Medicine at UCLA, Los Angeles, California, USA

Objectives: The upgrade of TomoEdge dynamic jaw was recently introduced to routine clinical practice. Our goal is to report the initial experience with the TomoEdge at UCLA by quantifying the dosimetric quality and delivery efficiency of swept jaw versus static jaw treatment plans.

Methods: A total of 16 cases, including five Head and neck, five localized prostrate and five prostrate with nodal involvement were selected in this study. For each case, four TomoHelical plans were generated using Tomotherapy planning system (V.5.0). The pitch and modulation factor were held constant for all plans, while different jaw and jaw sizes: 2.5 cm static vs. dynamic and 5 cm static vs. dynamic jaws were used in different plan. Plan quality was evaluated using the conformity index (95% isodose to the volume of the PTV), homogeneity index defined as the ratio of the maximum to the prescription dose, dose-volume histogram (DVHs) and dose profiles (defined at the center of the treatment volume in the longitudinal direction). To characterize the plan delivery efficiency, the treatment time and monitor units (MUs) of the four treatment plans were collected and analyzed.

Results: Both dynamic and static jaw techniques yielded clinical acceptable plans with comparable dosimetric indices as indicated by Table 1. The mean doses of the target in the dynamic plans are consistently lower than the corresponding static plans. The Homogeneity index and CI95 do not show a significant difference with regards to static versus swept jaws. Whereas, the CI50 index does show that 5 cm dynamic setting to be comparable to the settings with s 2.5 cm jaw. In Figures 1 and 2, the slope of the dose build up is visibly reduced for the dynamic settings. This reduction of dose build up is also apparent in Figure 3 which shows a trend of mean dose reduction to the non-treatment volume (NTV) with the dynamic jaw technique. Treatment time and monitor units scale are found to scale with jaw size with a limited dependence on static versus dynamic technique.

Conclusions: TomoEdge dynamic jaw plans greatly improve the longitudinal conformity. Similar treatment time was achieved for dynamic and static jaw plans using the same jaw sizes, however, ~ 50% of reduction of the delivery time is possible for 5 cm dynamic jaw plans. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Assessment of Anatomic and Dosimetric Variations for Head-and-Neck Radiotherapy via A GPU-based Deformable Image Registration Framework X. Sharon Qi (1), John Neylon (1), Robert Staton (2), Jason Pukala (2), Rafael Manon (2), Daniel Low (1), Michael Steinberg (1), Patrick Kupelian (1), Anand Santhanam (1) (1) Department of Radiation Oncology, Univ. of California Los Angeles, CA (2) Department of Radiation Oncology, UF Health Cancer Center-Orlando Health, Orlando FL 32806

Objectives: To systematically monitor the anatomic and dosimetric variations throughout the head-and- neck (H&N) treatment using a GPU-based deformable image registration (DIR) framework.

Methods: Eleven simultaneous integrated boost H&N patients treated on TomoTherapy (Accuray Inc., CA) were assessed in this retrospective study.The TomoTherapy plans were created using a fixed field width of 2.5 cm, modulation factor of 2.5 and pitch of 0.287. A daily pre-treatment megavoltage CT (MVCT) on TomoTherapy and weekly kVCT scans on a Philips Brilliance CT scanner (Philips Medical Systems, Netherlands) were acquired for each patient. The pre-treatment CTs were automatically registered with their corresponding planning CT through the in-house GPU-based DIR framework. The deformation of each contoured structure was computed to account for non-rigid change in the patient setup. The Jacobian determinant for the PTVs and the critical structures was used to quantify anatomical volume changes. Dose accumulation was performed to determine the actual delivered mean/minimum/maximum dose, equivalent uniform dose (EUD), and dose volume histograms (DVHs). A landmark tool was developed to determine the uncertainty in the dose distribution due to registration error.

Results: Interfraction patient anatomic changes and large dosimetric variations were observed. During the treatment courses of 6-8 weeks, the parotid volumes changed up to 34.7%, and the center-of-mass displacement of the two parotids varied in the range of 0.9-8.8 mm (mean: 4.9±2.3 mm). For the targets, the averaged cumulative maximum doses were consistent with the planned maximum doses within 1.6%. Mean doses were within 5% and 3% of the planned mean doses for all PTVs and CTVs, respectively. Specifically for the primary PTV1, the cumulative minimum dose, mean dose, and EUD were lower than the planned doses by 18%, 2%, and 7%, respectively. The averaged cumulative cord maximum doses were 1.06±0.15 than the planned doses. The cumulative mean doses assessed by the weekly kVCTs were significantly higher than the planned dose for both parotid glands (p=0.03 for the left parotid and p=0.006 for the right parotid). Moderate correlations were found between the dosimetric and anatomic variations. High precision GPU-based dose evaluation and accumulation is feasible with near real-time capabilities (~ 45 seconds) for registering each pre-treatment CT with the planning CT and dose accumulation. The registration accuracy for kVCT is at sub-voxel level (<1.5 mm).

Conclusions: The GPU-based DIR framework enables near real-time assessment of dose delivery. Integrating the framework into routine clinical workflow provides a timely indication of dose evaluation and plan adaption.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Improvement of megavoltage topogram registration for patient localization in TomoTherapy Jessica Scholey (1), Sharon Qi (2), Daniel Low (2), Benjamin White (1) (1) University of Pennsylvania, Department of Radiation Oncology; Philadelphia, PA (2) UCLA, Department of Radiation Oncology; Los Angeles, CA

Objectives: Orthogonal scout images (topograms) can be a fast and accurate alternative to megavoltage computed tomography (MVCT) for patient alignment during radiotherapy using the TomoTherapy Hi-ART system (Accuray, CA). Our goal is to improve the image quality of MV topograms for better patient localization.

Methods: Digitally reconstructed radiographs (DRR) of an anthropomorphic head and neck phantom were synthesized from kilo-voltage computed tomography (kVCT) under TomoTherapy geometry (1). Lateral (LAT) and anterior-posterior (AP) aligned topograms were acquired with a couch speed of 1 cm/s. The phantom was rigidly translated in all spatial directions with known offsets in increments of 5mm, 10mm, and 15mm to simulate daily positioning errors. An intensity-based image registration algorithm was used to register the MV topograms to a corresponding kV-DRR. The registration accuracy was assessed by calculating the normalized cross-correlation coefficient (NCC) between the MV topogram and the kV-DRR. This was compared with the known translations in the MV topogram to the calculated translation from the image registration. In addition, the topogram contrast was adjusted and noise was reduced with a low-pass frequency filter in Fourier space (FFT) and a Weiner filter that reduced stochastic noise caused by scattered radiation to the detector array.

Results: The correlation coefficients were greater for the filtered images compared with the unfiltered images. The accuracy was quantified by comparing the known phantom translations with the registration results. The registration provided accuracy at the sub-millimeter level. A summary of the NCC and accuracy results can be seen in Table 1. Figure 1 displays a qualitative example of the topogram registration with and without filtering.

Conclusions: The MV-topogram image quality was enhanced using FFT and Wiener filters. The automatic registration of the improved MV-topograms to a corresponding kV-DRR recovered simulated daily positioning errors with accuracy on the order of a millimeter. These results suggest the clinical use of MV-topograms as a promising alternative to MVCT patient alignment. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

UW Experience Commissioning 2x TomoHDA Systems Mark Geurts MS, Geoff Nelson PhD, Bishnu Thapa PhD University of Wisconsin-Madison

Objectives: The University of Wisconsin-Madison recently upgraded their two main campus TomoTherapy systems to TomoHDA.

Methods: The existing commissioning process was expanded to include validation of a new dynamic jaw beam model, TQA modules, and VoLO dose calculation algorithm. Additional tests were also included to compare the performance of previous Hi-Art systems to the new TomoHDA.

Results: Both TomoHDA systems were commissioned efficiently and showed improved performance, beam model accuracy, and reliability.

Conclusions: Installing and commissioning TomoHDA systems is a straightforward process and presents numerous advantages over previous TomoTherapy models.

The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

TomoTherapy Tips and Tricks Rick Vaden, RT(R)(T) CMD Senior Clinical Application Specialist, Accuray Incorporated

Topics this year include: • Selecting optimal planning parameters • Understanding MLC histogram • How does Pitch affect plan quality The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Twenty Years of SBRT Clinical Outcomes Jimm Grimm (1), Weili Ying (1), Alex Chen (2) and Jinyu Xue (3) (1) Holy Redeemer Hospital, Bott Cancer Center (2) Capital Health Medical Center (3) MD Anderson Cancer Center at Cooper

Objectives: Stereotactic body radiation therapy (SBRT) is transitioning from the era of expert opinion into the era of reliable outcomes statistics, and the goal of this presentation is to overview some recent tumor control probability (TCP) and especially normal tissue complication probability (NTCP) results, as well as efficient clinical implementation of this information. have also been in clinical use for more than twenty years.

Methods: A literature review of this time period has found 500 dose tolerance limits in 1 to 5 fractions throughout the body. In the past five years the amount of SBRT journal articles continues to increase rapidly and there are now more than 1000 dose tolerance limits for SBRT. For one critical structure at a time, these limits are being organized into a unified format of high-risk and low-risk dose tolerance limits, and statistical models of clinical outcomes data are being used to estimate the risk level of each selected limit. The charts depicting all the dose tolerance limits and corresponding risk levels are called DVH Risk Maps. The DVH Evaluator software tool is designed to apply these limits clinically and notify the user of compliance for each patient.

Results: DVH Risk Maps for aorta, brachial plexus, ribs, and spinal cord are presented. Each DVH Risk Map contains an organized complete set of dose tolerance limits in 1 to 5 fractions, in high-risk and low- risk categories, for five dose descriptors. The dose descriptors include the maximum point dose, the dose tolerance for two absolute volumes like D1cc and D5cc, and the dose tolerance for two percentage volumes like D50% and D10%, and the exact selection of dose descriptors is tailored to each critical structure. For each patient’s treatment plan, the DVH Evaluator can automatically select the low-risk dose tolerance limits whenever they are met and color code them green, automatically switch to the high-risk limits for any structure exceeding the low-risk limits and color code them yellow, and warn the user with red color coding and a quantitative message if any high-risk limits are exceeded.

Conclusions: The emerging dose tolerance information may be preliminary, but the presented estimated risk levels are sufficiently low and the dose tolerance limits are sufficiently high to enable physicians to confidently deliver ablatively potent doses to many tumors throughout the body. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric evaluation of accelerated partial breast irradiation using the CyberKnife Erwann Rault, T. Lacornerie, H. P. Dang, E. Lartigau, N. Reynaert, D. Pasquier Centre Oscar Lambret, 3 rue Frederic Combemale, 59000, Lille, France

Objectives: Accelerated Partial Breast Irradiation (APBI) is an alternative to traditionally fractionated whole breast radiotherapy for patients with limited risks of cancer recurrence. This treatment is expected to reduce side effects while being delivered in a short amount of time. Amongst all possible treatment modalities (brachytherapy, intra-operative radiotherapy and external beam radiotherapy), external beam radiotherapy is non-invasive, widely available and adaptable to the final pathology. Using the CyberKnife’s (CK) tracking ability (synchrony), margins to the CTV can be reduced to 3 mm as opposed to 10 mm for conventional radiotherapy. This is expected to spare surrounding tissues more effectively. The aim of this study was to verify the feasibility of using the CK for APBI. First, the tracking of the PTV using surgical clips implanted in the resection volume was evaluated using an anthropomorphic phantom. Second, a dosimetric comparison of three dimensional conformal radiotherapy (3DCRT), helical tomotherapy (HT) and CK was performed.

Methods: A realistic breast phantom (natural polyethylene, 0.97 g.cm-3) was designed using the measure- ments of 20 patients. The CIRS dynamic thorax phantom (model 008A) was used to simulate the thorax of the patients. Surgical clips were inserted inside the breast. A treatment plan was delivered to the mobile and immobile (gold standard) phantom. The motion compensation accuracy was evaluated using radiochromic films inserted inside the phantom and quantified using the gamma index. Treatment plans were calculated for 3DCRT, HT and CK on ten patients using the guidelines from the French APBI protocol SHARE. To equally compare the three techniques, margins applied to the CTV were set to 10 mm. However, another CK plan was calculated using 3 mm margins to evaluate the benefits of motion compensation.

Results: Only the larger surgical clips can be used to track the PTV in larger breast volumes. Using these clips, results show a motion compensation accuracy of less than 1 mm (gamma index below 1 for 3% of the maximum dose and 1 mm). All techniques (3DCRT, HT and CK) meet the guidelines from the SHARE protocol. The dose volume constraints imposed by this protocol being very strong, few dosimetric differences exist on the PTV coverage and sparing of the lungs and heart. However, results show that the CK is useful to reduce high doses received by the non target breast tissue volume (NTBTV). This effect is further enhanced using motion compensation and 3 mm margins to the CTV.

Conclusions: APBI using the CK is feasible. Non-coplanar beams are used to protect the NTBTV. If surgical clips used to delineate the resection volume are big enough to be tracked, PTV margins can be reduced to 3 mm which can further reduce high doses to the NTBTV for better cosmetic outcome. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Multi-Institutional Retrospective Analysis of Gold Anchor Fiducial Implantation and Tracking for Robotic Radiosurgery Oliver Blanck (1 and 2), D. Bodusz (3), S. Luchkovskyi (4), M. Chan (5), M. Alraun (6), L. Leschenko (4), W. Miśta (3), G. Gaffke (7) and Hunold P (1) (1) University Clinic Schleswig-Holstein, Lübeck, Germany (2) CyberKnife Center Northern Germany, Güstrow, Germany (3) Maria Sklodowska-Curie Memorial Cancer Center, Gliwice, Poland (4) CyberClinic Cancer Center Spizhenko, Kiev, Ukraine (5) Tuen Mun Hospital and University of Hong Kong, Hong Kong (6) Schwarzwald Baar Klinikum, Villingen-Schwenningen, Germany (7) KMG Klinik, Güstrow, Germany # Equal contribution

Objectives: X-ray based landmark tracking is often used for precise radiosurgery treatment i.e. with the robotic CyberKnife system (Accuray, USA). Based on x-ray visibility bony structures such as skull or spine can be easily located with great accuracy. For targets in soft tissue like lung, liver or prostate artificial gold marker (fiducials) need to be implanted to enable precise tracking of landmarks in the targets close proximity. Fiducial implantation is amongst others routinely performed through percutaneous CT- or US-guided 17-19 gauge (g) needle punctures into or close to the target. However, this procedure bears risks such as bleeding (liver) or pneumothorax (lung) which can be as high as 33-67% with 9-33% of the pneumothoraces requiring intervention (i.e. chest tube). To decrease the potential risks of fiducial implantation the smaller 22-25g Gold Anchor (GA) needles (Naslund Medical AB, Sweden) were recently introduced which contain a fine gold chain that can be folded into a ball like structure at the time of implantation. We now wanted to retrospectively analyze the side effects from the GA implantation and its usefulness as landmarks for robotic radiosurgery tracking.

Methods: To assess the accuracy of the different shapes (ball, line and ball-line-combination) that can arise from the GA during implantation various phantom studies have been performed according to the vendor’s and our in-house protocols and compared to baseline with standard fiducials. For the assessment of side effects and usefulness during CyberKnife treatment a total of 308 implanted GA in 104 patients from three CyberKnife centers have been retrospectively analyzed (2011-2013). 148 GA (22g, 20mm anchor length) were implanted in 54 patients (mean age 70.8 years) under US-guidance and local anesthesia into the prostate through the rectum with preventative admission of antibiotics (Azithromycinum) for three days. 132 GA (55 x 22g, 77 x 25g, 2 x 10mm and 130 x 20mm anchor length) were implanted in 38 patients (19 male, 19 female, mean age 58.9 years) under US-guidance (24) or CT-guidance (14) into the abdomen (liver, pancreas and kidney) either under local anesthesia (16) or without (22). 29 GA (3 x 22g, 26 x 25g, 21 x 10mm and 8 x 20mm anchor length) were implanted in 11 patients (7 male, 4 female, mean age 66.2 years) under CT-guidance into the lung either under local anesthesia (10) or without (1). Average time between implantation and planning CT was 8 (lung), 10 (liver) and 11 (prostate) days (Min 1 day, Max 37 days).

Results: The CyberKnife phantom tracking accuracy of the ball, ball-line and line shape GA was not different compared to standard fiducials. However, in larger phantoms the visibility of the line (both 0.28mm and 0.4mm) and the 10mm GA (0.28mm) was low which may reduce the tracking accuracy and hence the possibility of false fiducial tracking and long treatment times in patients significantly. For the patient analysis 4 out of 308 GA (1.3%) were lost during or after implantation (i.e. by accidental placement The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

into a liver vein) while fiducial migration was not observed. CT artifacts from implanted GA were also not noticed especially when compared to 3-5mm x 1-1.2mm standard solid gold fiducials implanted through 17-18g needles. While general all GA were intended to be deployed as ball (in some rare occasions as ball- line-combination) 272 GA (88.3%) deployed as ball, 19 GA (6.2%) deployed as ball-line-combination and 17 GA (5.5%) deployed as line (either due to inexperience of the implanter or in the liver due to lack of deployment resistance). Due to line or ball-line GA shape or too close implantation 38 of 304 GA (12.6%) were not usable for CyberKnife tracking (7.1% if excluding too close or intended line shape GA). Only 1 line shape GA was used as sole fiducial for CyberKnife tracking. Out of 93 patients (280 GA) only 1 patient (1 GA) developed minor infection (prostatitis) for all abdominal or prostate fiducial implantation. For the 11 lung patients (29 GA placements) 6 patients (54.5%) developed a minor pneumothorax from respectively 6 GA (20.7%) which however resolved by itself under close observation. Other side effects were not noticed. Pain score was available from 19 abdominal and 47 prostate patients and rated on average 3.15 (abdomen) and 1.38 (prostate) based on the commonly available pain score scale (1-10 with 10 being maximum pain).

Conclusions: The 20mm 22-25g Gold Anchor (GA) folded as ball shape is safely and effectively usable for CyberKnife tracking, does hardly migrate and does generally not generate CT artifacts. However, the deployment requires some training and great care is advised during planning and treatment with the 0.28 x 10mm GA due to visibility and the GA in line shape due to error in fiducial locating along the line. Minor side effect occurrences are rare in prostate and abdomen while for lung the pneumothorax rate appears to be similar compared to larger needles (lacking larger implantation numbers though). Nevertheless, compared to larger needles the pneumothorax severity was much lower in our retrospectively analysis as all patients required only observation after implantation. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Intelligent margins for SBRT based on tracking fiducials Pavel Dvorak (1), Ashley Richmond (1), Andy Gaya (1), Iciar Santaolalla (2), Alejandro Floriano (2), Rafael Garcia (2), Lukas Knybel (3), Bretislav Otahal (3), Jakub Cvek (3), David Feltl (3), (1) The London Clinic, London, UK; (2) Centro de Radiocirugia y Radioterapia Robotizada Cyberknife, Grupo Imo, Madrid, Spain; (3) FN Ostrava, Czech Republic

Objectives: Target tracking using fiducial surrogate is used for breathing-related tumor motion management in SBRT using Cyberknife for all non-lung and some lung sites. The key assumption is that there is a rigid bond between the tracked fiducials and all parts of the tumor during whole breathing cycle.

Methods: We developed an accurate quantitative method for fiducial-tumor geometry assessment and propose 2 ways to significantly reduce uncertainty due to fiducials-tumor geometry deformation during breathing cycle. The method is based on a conventional planning CT acquired at expiration (exp) and one extra CT at inspiration (ins). Then the GTV and fiducials are contoured on both CTs, exported in DICOM format to MATLAB where a dedicated application performs an analysis including identification of voxels which need to be added to the original (planning) GTVexp to eliminate risk of tumor underdose during inspiration due to geometry deformation. The algorithm is based on a comparison of each tumor voxel transform from relevant fiducials at inspiration to the actual tumor contour at expiration (planning) CT. The result verifies the relevance of original planning GTVexp for inspiration phase. The smaller extra volume for given fiducial configuration, the better the original planning GTVexp represents the tumor at inspiration. Rating fiducial configurations based on this criterion can help in choosing a strategy for tracking. However, to fully explore this method potential, one can use this result to correct the original planning GTVexp and eliminate the risk of underdose either via determination of minimum anisotropic margin to cover original volume plus extra voxels identified, or by making the composite volume available in the planning system to correct the original GTVexp accordingly via an artificial secondary image.

Results: Results based on 10 patients from 3 institutions show significant individual character among both patients and individual fiducials. The extra volume required to eliminate underdose at inspiration often exceeds 20% of the original GTV. The original GTVexp correction based on a secondary CT image template is more accurate than the alternative of a straightforward anisotropic margin.

Conclusions: The proposed method based on computerized 3D analysis of fiducials-tumor geometry reduces uncertainty associated with fiducials-tumor deformation during breathing cycle. The resulting target volume can be presented as an application of an individualized anisotropic ‘intelligent’ margin. The method does not address further aspects of a PTV margin such as uncertainty of tracking fiducials themselves. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

The Method of improving DRR contrast of Cyberknife by generating dual-energy CT image dataset from single-energy CT image dataset Yang Dong, Jie Huo, Xuemin Wang, Ping Wang, Xianfeng Zhu, Yuanming Feng Department of Radiotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, People’s Republic of China

Objectives: The capability of obtaining tissue-specific information from dual-energy imaging has the potential to be used in radiotherapy for gross-tumor-volume (GTV) definition and localization with enhanced accuracy in Cyberknife treatment planning and image guided delivery. However, there are not dedicated dual energy CT (DECT) simulators in radiotherapy clinics yet. This study is to develop a method to create a set of DECT data with the data from a conventional single-energy CT simulator, i.e., to generate a set of CT images at energy B from a set of CT images obtained at energy A, and to explore the feasibility of utilizing the two CT data sets to create anatomical images with higher soft-tissue-contrast.

Methods: In the new method, HUs in the original images of CTA was first converted into liner attenuation coefficients at another energy with a bilinear scaling method used for attenuation correction in SPECT and PET imaging. Photon attenuation of tissues with higher Z-numbers has stronger energy dependence than the ones with lower Z-numbers, and has a sharp decrease as the x-ray energy increases. Therefore, two scaling factors are required for higher Z-number tissues and lower Z-number tissues respectively when converting CT numbers from different energy. Tissues with HUs in the range of -1000 to 0 were assumed as the mixtures of water and air while tissues with HUs larger than 0 were assumed as the mixtures of water and bone.

Results: CT images from 5 lung cancer patients were used in this feasibility study. The images were acquired with a Brilliance Big Bore CT simulator at energy A (CTA, 120kVp). For each patient, one set of CT images at energy B (CTB, 30keV) was generated from CTA with a bilinear scaling method, two pairs of digitally reconstructed radiographs (DRRs) were created from CTB and CTA respectively and then a soft- tissue-only DRR pair (DRRdualE) was obtained using an in-house software of dual-energy subtraction with DRRCTA and DRRCTB. The image quality of DRRs was quantitatively analyzed using signal-difference- to-noise-ratio (SDNR). The results indicate that the generated CT images showed improved contrast and the DRRdualE showed that bony structure was eliminated, soft tissue contrast was improved. SDNR for GTV was improved from 1.94 ± 0.09 (in DRRCTA) to 4.31 ± 0.12 (in DRRdualE).

Conclusions: The feasibility study has shown the potential of utilizing a conventional single-energy CT dataset to get another set of CT images at a different energy to achieve improved soft tissue contrast for GTV delineation or target localization when a DECT machine is not available. And futher more, this method could be applied in generating dualE DRRs for dualE x ray generators of Cyberknife which may be a new feature in the future. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

A novel end-to-end test system in assessing the beam-by-beam delivery accuracy for CyberKnife system Lei Wang (1), Lei Xing (1), Brett Nelson (2) (1) Radiation Oncology Department, Stanford Cancer Center, Palo Alto, CA (2) Logos System, Scotts Valley, CA

Objectives: To develop and assess a novel end-to-end test system using a CCD camera and a scintillator based phantom that is capable to measure beam-by-beam delivery accuracy of Cyberknife stereotactic radiation therapy system.

Methods: The XRV-100 phantom is composed with a scintillator imaging cone coupled with a CCD camera. During the radiation delivery, the CCD camera captures the two light spots where the radiation beam intersected with the scintillator imaging cone. The real time recorded 2D image sequences are used to reconstruct the beam vectors, the beam flux maps as well as the beam on time. The phantom is first scanned with a GE CT scanner with slice thickness of 0.625 mm and exported to the Cyberknife Muliplan (v4.6) treatment planning system. Two treatment plans are created with an approximately 1x1x2 cm3 target in the middle of the cone. Beams that go through the end of the cone are blocked during the treatment planning to ensure that all the beams are measurable. Two non-isocentric similar plans are created to deliver 900 cGy and 500 cGy maximum doses to the center of the target respectively. Each plan contains 40 non-isocentric and non-coplanar beams using 10 mm fixed collimator. The plans are delivered on the Cyberknife G4 system with fiducial tracking on the four metal fiducials embedded on one end of the cone. The image sequences are recorded real time during the delivery and analyzed with VolumeWorksCK software. Plan 1 is delivered once while Plan 2 is delivered twice to test the delivery reproducibility. The phantom is repositioned between the deliveries to ensure that the image guidance is performed independently between the three deliveries. The beam vectors measured are compared with the planned vectors from the machine delivery file (XML file) exported from the treatment planning system. The differences of the coordinates, including the translational coordinates X, Y and Z and the angular coordinates Theta and Phi between the measured and the planned are analyzed. The average of the beam-by-beam delivery accuracy and maximum deviation are used to assess the overall delivery accuracy of the Cyberknife system.

Results: The coordinates of the captured beam vectors in the XRV-100 data are aligned with the XML file coordinates successfully. The matching process is needed because the beam list does not necessarily contain the order of beam delivery. The average overall delivery accuracies of the three deliveries are 0.63 ±0.25 mm, 0.66 ± 0.27 mm, and 0.60 ± 0.25 mm respectively. Maximum deviations for the three deliveries are 1.30 mm, 1.48 mm, 1.31 mm respectively. To assess the reproducibility, the coordinate differences of the two deliveries of Plan 2 are calculated. The average translational reproducibility is 0.14 ± 0.04 mm with most difference contributed from Z direction (0.12 ± 0.06 mm). This agrees with the fact of relative poor image resolution on digital reconstructed radiography (DRR) used for imaging guidance in this direction. Average reproducibility on Theta and Phi are 0.22 ± 0.01 degree and 0.00 ± 0.01 degree respectively.

Conclusions: The XRV-100 system has proven to be a powerful tool in performing end-to-end tests of CyberKnife plan delivery. The experimental results agree with stated sub-millimeter delivery accuracy of Cyberknife system, and the highly reproducibility in the measurements verifies the stated 0.2 mm XRV- 100 device accuracy. Compared to conventional film-based end-to-end test systems, the XRV-100 provides consistent beam-by-beam delivery accuracy measurements of complex non-isocentric plans and has the potential to be a more sensitive alternative for measuring machine performance deterioration. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Patient-Specific QA for CyberKnife Plans Using 2D Ion Chamber Array Sebastian Adamczyk, Agnieszka Skrobala, Marta Adamczyk, Bartosz Pawalowski Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland

Objectives: The aim of this study was to compare the results of patient-specific QA for extra- and intracranial SBRT treatment plans using 2D ion chamber array and point dose measurements with small ionization chambers.

Methods: 20 extracranial and 20 intracranial CyberKnife plans were dosimetricaly evaluated by point dose measurements with small ionization chambers – SemiFlex 31010 and PinPoint 3D 31016 (PTW) placed in a water equivalent (RW3) slab phantom (IBA Dosimetry) and by planar dose measurements with liquid-filled ionization chamber array - Octavius SRS 1000 (PTW). Measured point doses were compared with mean dose values calculated by treatment planning system (TPS) in active volume of a chamber. Homogeneity index (HI) in active volume of a chamber ((D_max-D_min)/D_mean ) was also reported for each plan. The planar dose distribution evaluation was based on the Gamma index with two sets of acceptance criteria: distance to agreement (DTA) of 2 mm and dose difference (DD) 3% or 2% (calculated from prescribed dose). The scoring parameter was the percentage of the field area (defined by the threshold of 5% from maximum dose value of measured data set) resulting with γ ≤ 1 (%score). HI value was calculated for each plan based on minimum, maximum and average dose values predicted by TPS in array measurement plane. Normalized homogeneity index (nHI) was assessed as a HI per cm2 of array irradiated area.

Results: When point dose verification was performed any of extracranial CyberKnife treatment plans failed the acceptance criteria (3% difference between measured and calculated dose). The difference for all plans was 0,89±0,83% (mean ± 1SD) and the HI=0,044±0,017. However for the same group of plans detailed planar dose analysis showed 1 plan which did not meet the gamma acceptance criteria (DD=3%, DTA=2mm and %score≥95%). The average %score value was 98,94±1,59%, HI=4,087±2,591 and nHI=0,068±0,082.The selected group of plans was analysed with tighter dose criteria – 2% both for point dose measurements as well as gamma evaluation. For this criterion 1 plan did not pass the point dose verification with dose difference of 2,5% (37,5cGy absolute difference). Moreover 3 plans did not meet the gamma criteria. Average score value was 96,10%±4,16%. The analysis results were significantly different for the intracranial SBRT treatment plans. The mean HI value for dose distribution calculated in the active volume of chamber was 0,090±0,035, which is 2 times higher than for extracranial plans. Because of chamber volume averaging effect 2 and 4 treatment plans did not meet the point dose acceptance criteria of 3% and 2% respectively. However when planar dose verification has been performed all treatment plans pass the gamma acceptance criteria regardless of criteria used DD=3% or 2% with DTA=2mm. The average score values in that group are reported in Table 1. The SRS array performed very well even though the dose inhomogeneity was much larger than for intracranial plans (HI=11,776±5,813 and nHI=0,342±0,321).

Conclusions: This study showed that the high-resolution array of ionization chambers is a precise dosimetric tool for patient-specific QA even when measuring highly inhomogeneous dose distribution. Point dose measurement seems to be an insufficient QA method to perceive the errors in proper dose distribution delivery. It is therefore crucial to perform planar dose verification for patient-specific QA of SBRT treatment with carefully chosen acceptance criteria. The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

CyberKnife Tips and Tricks Kari Cann, MS DABR Senior Support Medical Physicist, Accuray Incorporated

Topics this year include: • Troubleshooting Iris Variable Collimator QA • Optimizing E2E Planning for XLT • Using Image J for Laser/Radiation Coincidence with EBT Film • Review of the CyberKnife Imaging Dose POSTER ABSTRACTS The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 Scientific Poster Abstracts 5:00—6:30 pm, Tuesday May 6 Poster Presentation Session: Minneapolis Grand Ballroom

POSTER AUTHOR INSTITUTION TITLE NUMBER CyberKnife Radiosurgery for Shinichiro CyberKnife Center, Squamous Cell Carcinoma of the 1 Mizumatsu Aoyama General Hospital External Auditory Canal: Case Report Département universitaire Robotized fractionated stereotactic de radiothérapie - Centre radiation for uveal melanoma: local S. Horn 2 Oscar Lambret, Lille, control and toxicities at 30 months France median follow-up Département universitaire Robotized hypofractionated de radiothérapie - Centre stereotactic radiation for uveal S. Horn 3 Oscar Lambret, Lille, melanoma: eye displacements and France margins Dosimetric comparison of conventional radiotherapy with two Department of Radiation techniques of TomoTherapy viz. T. Wadasadawala Oncology, Tata Memorial 4 Helical Tomotherapy and Tomodirect Centre in patients with synchronous bilateral breast cancer (SBBC) Total Marrow and Lymphatic Cancer Treatment Centers Irradiation (TMLI) with the Douglas Kelly 5 of America TomoTherapy HDA and VOLO planning software Radiation Oncology Regular Fractionated Radiation 6 Lei Wang Department, Stanford Therapy for Peri-optic and Peri- University Medical School brainstem Tumors with Cyberknife Dosimetric comparison of different Neurological Institute C. external photon beam techniques E. De Martin 7 Besta, Milan, Italy to deliver accelerated partial breast irradiation Validation of the Iris Quality Centro Diagnostico A. Martinotti Assurance Tool for a Cyberknife 8 Italiano, Milan, Italy system Dosimetric Comparison of Cyberknife with MLC versus Linac-based Lane Hayes Alliance Oncology 9 Intensity Modulated Radiation Therapy in Prostate Cancer University of Palermo- Helical Tomotherapy: our experience A.Grillo 10 Italy in treatment of Head and Neck cancer The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 Scientific Poster Abstracts 5:00—6:30 pm, Tuesday May 6 Poster Presentation Session: Minneapolis Grand Ballroom

POSTER AUTHOR INSTITUTION TITLE NUMBER Frameless fractionated stereotactic 21st Century Oncology of radiotherapy (FSRT) for brain James C. Marsh 11 Arizona metastases using helical tomotherapy: clinical outcomes UVA Department of Overcoming Reimbursement Radiation Oncology Limitations When Utilizing 3D Quan Chen 12 and Culpeper Regional Conformal Tomotherapy for Adjuvant Hospital Breast RT Bilateral Breast Irradiation: Tomo Siji Nojin ACTREC, TMC 13 Versus 3D-CRT University of Florence- TomoTherapy treatment of moving S. Pallotta 14 Italy lesions: a phantom study Orange County Recurrent Head & Neck Cancer 15 Ajmel Puthawala CyberKnife and Radiation SBRT: Retrospective Outcome Oncology Center Analysis Exit-detector based dose University of Wisconsin- Mark Geurts reconstruction as a supplement for 16 Madison TomoTherapy IMRT QA University of Wisconsin- Total Skin TomoTherapy for Mark Geurts 17 Madison Treatment of Mycosis fungoides Image guided hypofractionated radiotherapy with simultaneous integrated boost with helical G. Mortellaro University of Palermo 18 tomotherapy for definitive treatment of prostate cancer: preliminary results on acute outcomes. London Regional Cancer Program, London (ON) Image Guidance Options for Prostate Slav Yartsev 19 Health Sciences Centre Cancer Patients and Western University University Clinic Review of Clinical Accuracy Analysis O. Blanck Schleswig-Holstein, 20 for Robotic Radiosurgery Lübeck, Germany The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 Scientific Poster Abstracts 5:00—6:30 pm, Tuesday May 6 Poster Presentation Session: Minneapolis Grand Ballroom

POSTER AUTHOR INSTITUTION TITLE NUMBER A phase II study to evaluate the CyberKnife Center of efficiency and safety of locally Ping Wang 21 Tianjin Cancer Hospital advanced pancreatic adenocarcinoma treated with CyberKnife® SBRT First Affiliated Hospital The research on the factors affecting Qi Yue of Kunming Medical 22 the passing rate of TomoTherapy DQA University Centre Oscar Lambret Workflow optimization for F. Crop 23 and Université Lille CyberKnife treatments Dosimetric comparison of University of Florence, Cyberknife and Helical Tomotherapy Daniela Greto 24 Florence, Italy Radiosurgery for single brain metastasis President, CyberKnife® The CyberKnife® Coalition: Linda Winger 25 Coalition Advocating for Patient Access The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

CyberKnife Radiosurgery for Squamous Cell Carcinoma of the External Auditory Canal: Case Report Shinichiro Mizumatsu1, Toshinori Kawamura2, Yoshimasa Mori2 1) CyberKnife Center, Aoyama General Hospital, 2)Department of Radiology, Aichi Medical University

Objectives: The external auditory canal (EAC) cancer is a rare tumor with an annual incidence of one - six per one million inhabitants. We report a case of CyberKnife Radiosurgery (CKR) for the EAC cancer

Methods: A 84-year-old woman presented with left hearing disturbance and otalgia in September 2009. MRI demonstrated the lesion in the posterior wall of the left EAC. The lesion’s pathology was squamous cell carcinoma as a result of the biopsy. There was no distant metastasis and the lesion existed only in the left EAC. It was difficult for her to receive surgery and chemotherapy for the lesion because of her age and kidney dysfunction. She was referred to our hospital for CKR. She was treated with CKR at a marginal dose of 24Gy in three fractions. The tumor volume at the time of CKR was 0.278 cm3.

Results: Her symptoms improved completely and the tumor disappeared for a short period of time. No severe early side effects were noted after CKR. At 4 years follow-up, she remains stable condition without recurrence or distant metastasis.

Conclusions: CKS may be indicated for early EAC cancer for its efficacy and lack of side effect. Therefore, an early detection of the EAC cancer is important in order to utilize the advantage of CKR.

Poster 1 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Robotized fractionated stereotactic radiation for uveal melanoma : local control and toxicities at 30 months median follow-up. S.Horn1, X. Mirabel1, T.Lacornerie1, E. Lartigau1, P. Labalette2 1 Département universitaire de radiothérapie - Centre Oscar Lambret – 59000 Lille 2 Service d’ophtalmologie – Hôpital Claude Huriez – Lille 59000

Objectives: Radiation therapy is the gold-standard for the treatment of uveal melanoma. The technique of choice for small and median-sized melanomas is charged-ion radiation therapy (Proton, Helium). I125 Brachytherapy may be considered for selected small tumours. However, access to these two methods of treatment may be an issue, especially for elderly or disabled patients. We present here the clinical results of 16 patients treated with fractionated stereotactic radiation with the Cyberknife® system in an entirely non invasive setting. We report the control and toxicity rates for this treatment at 30 months of median follow-up.

Methods: We report a retrospective series of 16 patients treated for uveal melanoma between may 2008 and may 2013, that had refused or were unsuitable for therapeutic alternatives (Proton therapy, brachytherapy, enucleation). Patients were treated with 45 Gy in 3 fractions of 15 Gy. Ocular immobilisation was obtained by palpebral occlusion such as described by Miralbell et al. (TCRT 2007). The analysis of ocular displacements and subsequent margins for our series is reported elsewhere, and confirms the safety of this method with a 2.5 mm margin from the GTV to the PTV. Every patient underwent repeated ophtalmologic examination, and local control was assessed with ocular US scan and/or MRI. We report the relapse and metastasis-free control rates, the ocular preservation rate, and toxicities.

Results: Median follow-up is of 30 months (3-58 months). Median age at treatment time was 70 years. Most tumours were of small or median size. The mean diameter was 9.4 mm, while the mean width was 4.8 mm. In matter of tumour control, one local relapse was debated, but not alleged, as that patient was also diagnosed with metastases and was lost to follow-up. The local control rate was thus of 94-100%. Two metastasic relapses were alleged to the liver at 19 and 21 months, which is a metastatic control rate of 88%. Finally, 2 enucleations were indicated, of which one was refused by the patient, which is an enucleation rate of 12%. Grade 3-4 radiation complications were observed in 8 out of 16 patients (50%): 4 retinal detachments, 1 cataract, 3 radiation retinopathy, 1 intravitreous haemorrhage and 2 neovascular glaucomas. Treatments were as follow: vitrectomy and phakoemulsification (1 patient), intravitreous bevacizumab injections (6 patients, median of 4 injections), panphotocoagulation (5 patients), and laser iridotomy /IV hypotonic treatment (1 patient). Treatment recourse classified the patient as subject to grade 3-4 toxicity which may be a bias.

Conclusions: Literature reports for local and metastatic control rates of approximately 95 % and 90% respectively; secondary enucleation rates and grade 3-4 toxicities are of as much as 10-20% and 30-60% respectively depending on the technique. Toxicity evaluation may be biased by the pretreatment visual condition and the functional character of the eye. Our preliminary results seem in agreement with other findings. Further patients and follow-up are necessary.

Poster 2 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Robotized hypofractionated stereotactic radiation for uveal melanoma : eye displacements and margins. S.Horn1, T.Lacornerie1, X. Mirabel1, P. Labalette2, E. Lartigau1 1 Département universitaire de radiothérapie - Centre Oscar Lambret – 59000 Lille 2 Service d’ophtalmologie – Hôpital Claude Huriez – Lille 59000

Objectives: We report the treatment with hypofractionated stereotactic radiotherapy of 16 uveal melanoma patients that were deemed unsuitable for proton therapy or brachytherapy. They were treated with a minimally invasive technique, eyelids closed, without any eye fixation device or retrobulbar anaesthesia. The purpose of this study was to evaluate the eye displacements throughout the treatment and to discuss the subsequent margins for a fractionated stereotactic treatment with the Cyberknife® system. Our preliminary results indicated that our 2.5 mm margin around the GTV was sufficient to treat our patients safely without jeopardizing the local control rate. We report here the actualised results on 16 patients.

Methods: All patients received 45 Gy in 3 fractions of 15 Gy at the 80% isodose. On the basis of the publication by Miralbell et al. (Tcrt 2007), patients were treated eyelids closed. Indeed, repeated retrobulbar anaesthesia was considered as too invasive in a fractionated setting, and the treatment sessions were too long (mean: 45 min) to use an eye fixation device. Therefore, the repositioning was done to the orbit with a 0.5 mm clinical precision, which is enabled by the Cyberknife® system, and patients were thus effectively treated with a 2.5 mm margin from the GTV to the PTV to account for repositioning and eye displacements. Patients underwent a CT scan in treatment position before every session. We delineated the GTV, the ocular globe and the lens on every exam. The lens was used as a surrogate marker for eye displacement. For each patient, we registered the different images using a rigid algorithm to the skull, and we compared the maximum displacements for each ROI in the 3 axes. Subsequent margins were calculated according to McKenzie et al. (Phys Med Biol 2000).

Results: Mean maximum displacements for the lens were 1, 2.14 and 1.35 mm (standard deviations: 0.56, 0.79 and 0.59 mm) in the antero-posterior, cranio-caudal and left-right axes respectively. More specifically, for 5 patients out of 16, the maximum displacements were superior to 2 mm, and for 2 of them, were even superior to 3 mm, but these measures were always found in the cranio-caudal axis, were the uncertainties were maximal. We calculated that the necessary margin from the GTV to the PTV are 1.4, 2 and 1.5 mm in the antero-posterior, cranio-caudal and left-right axes respectively, to which must be added the 0.5 mm of the repositioning to the orbit.

Conclusions: This update confirms that the displacements of the ocular globe and lens when simply closing the eyelids are limited, and that treatment with a minimally invasive method is feasible and safe with a 2.5 mm margin. Clinical results are reported elsewhere and are encouraging, in agreement with other findings. Caution must be paid to the initial definition of the GTV, as local control is crucial for the treatment of uveal melanoma.

Poster 3 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric comparison of conventional radiotherapy with two techniques of TomoTherapy viz. Helical Tomotherapy and Tomodirect in patients with synchronous bilateral breast cancer (SBBC) T Wadasadawala1, B Visariya1, R Upreti2, S Paul2, R Phurailatpam2, R Sarin1 1Department of Radiation Oncology & 2Department of Medical Physics, Tata Memorial Centre

Objectives: Feasibility of planning SBBC with two techniques of tomotherapy viz. Helical Tomotherapy (HT) and Tomodirect (TD) in Intensity Modulated Radiotherapy (IMRT) and Three Dimensional Conformal Radiotherapy (3DCRT) mode and dosimetric comparison with conventional bitangential technique and Field in Field (FIF) IMRT.

Methods: 10 women with SBBC (Breast conservation on both sides=4, mastectomy on both sides=4 and breast conservation on one side with mastectomy on other side=2) were planned for adjuvant RT to whole breast or chest wall using FIF-IMRT, HT, TD-3DCRT and TD-IMRT techniques. These techniques were compared with conventional bitangential technique for target coverage and organ at risk (OAR) sparing. Six women with breast conservation on at least one side were planned for boost to tumor bed using electrons (with conventional), or with HT boost (with TD-3DCRT and TD-IMRT) or with simultaneous integrated boost (SIB) using HT. Prescribed dose (PD) was 50Gy in 25 fractions for breast or chest wall and 15Gy in 6 fractions for boost with all techniques except HT with SIB where TB was prescribed 61Gy in 25 fractions.

Results: It was feasible to treat SBBC with newer techniques keeping Planning Target Volume (PTV) coverage (V95) equivalent. When evaluating without boost plans, volume outside PTV receiving >107% of PD was lower with HT-IMRT and higher in TD-3DCRT and TD-IMRT p=NS. However, the hotspot was significantly less with FIF-IMRT. For total lung and heart, V40 & V30 were significantly low with HT-IMRT with comparable V5 volumes and mean doses. V5 and mean dose was significantly less in TD- 3DCRT and TD-IMRT plans both for total lung as well as heart. FIF-IMRT did show pulmonary sparing but significantly reduced mean dose and V5 of heart. All four technique of delivering boost to tumor bed were comparable in terms of PTV coverage. For OAR sparing, it was seen that HT-IMRT with SIB had significant reduction in V40, V30, V20 and mean dose and non significant reduction in V10 & V5 for total lung. Tomodirect 3DCRT and IMRT with helical tomotherapy boost had significant reduction in V10 only for total lung. Cardiac sparing was seen with both techniques but only TD-IMRT resulted in significant reduction of V5. FIF-IMRT significantly reduced V5 of heart without affecting other parameters for heart or lung.

Conclusions: This dosimetric study demonstrates cardio-pulmonary sparing with both the modalities of Tomotherapy in the setting of SBBC. TD-IMRT may be useful for bilateral chest wall irradiation whereas HT-IMRT may be useful for bilateral breast irradiation with simultaneous delivery of tumor bed boost. FIF-IMRT improves the dose homogeneity without significant reduction of OAR doses.

Poster 4 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Total Marrow and Lymphatic Irradiation (TMLI) with the TomoTherapy H.D.A. and VOLO planning software Douglas Kelly, MD; Denise Lollar, CMD; Amarjit Sen, PhD Cancer Treatment Centers of America

Objectives: At our treatment center patients who require radiation therapy as part of their myeloablative conditioning regimen for stem cell transplantation will typically undergo a dose of 200 cGy x 6 fractions = 1200 cGy, prescribed to an individualized set of target organs and delivered via helical intensity modulated radiation therapy (IMRT). We recently upgraded to a Tomo H.D.A. machine and the VOLO treatment planning software. This report describes our experience with preliminary experience with this new technology for TMLI.

Methods: The patient underwent full body CT simulation while in a vacuum immobilization bag and a head mask. He was supine, with legs together and arms against the body. A junction line was created 3cm below the hands, dividing the patient into upper and lower body, which was required due to the 160cm maximum field length. Targets included the complete skeleton excluding the maxilla and mandible, all lymph node chains, the spleen, sites of previous and current disease, as well as the brain and testes sanctuary sites for this leukemia patient. Organs were contoured, and each organ could be designated as a Target (bones, nodes, spleen, brain, testes), Hypodosed target (Liver and Retinas at 50%), Boosted target (not used), Avoidance (heart, lung, kidneys, etc), or Reference (skin, muscles, etc). Margins were added. A gap of 1.5 cm was used in between the upper and lower body fields. The treatment time was greatly shortened with VOLO software. With our prior non-VOLO system, it took 22 hours to calculate beamlets for a TMLI plan but this was eliminated with VOLO.

Results: The upper body targets were 21.0L in total. The total upper body volume was 53.3L. The target volume that was prescribed 12 Gy was analyzed: 95% received at least 11.2 Gy, 80% received at least 12.23 Gy, and the hottest 20% received at least 12.89 Gy. The dose heterogeneity index (DHI) was excellent at 0.055. The median dose to avoidance organs included lenses 2.34 Gy, oral cavity 5.01, parotids 3.51, heart 6.54 , lungs 6.76, kidneys 5.15, and small bowel 8.46 Gy. Treatment time to the upper body was 36.6 minutes and the lower body was 13.4 minutes, for a total of 50.0 minutes beam on time.

Conclusions: VOLO offered a faster treatment planning experience, and the H.D.A. dynamic jaws allowed us to use the maximum sized jaw (5cm) yet still achieve very good target homogeneity and dose reduction in avoidance organs.

Poster 5 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Regular Fractionated Radiation Therapy for Peri-optic and Peri-brainstem Tumors with Cyberknife Regular Fractionated Radiation Therapy for Peri-optic and Peri-brainstem Tumors with Cyberknife

Objectives: The advancement of Cyberknife technology in the past few years leads to significant reduction to the treatment time, which opens the possibility of applying Cyberknife technology for regular fractionated radiation therapy (CK IMRT). Near 10 patients with peri-optic and peri-brain stem tumors have been treated with CK IMRT at Stanford since 2011. This work assesses feasibility and benefits of CK IMRT compared with Linac based treatment.

Methods: Three previously treated CK IMRT cases (near orbital meningioma) with planning tumor volumes (PTV) of 1.4 cc, 5.8 cc and 26.2 cc are selected for this study. For comparison purpose, the prescription doses are re-normalized to 54Gy in 30 fractions to cover 95% of the PTV.Dose limit to the critical structures follows RTOG 0539. CK plans are created using MultiPlan 4.6 on Cyberknife G4 system with fixed or Iris collimators and 1000 MU/minutes dose rate. The patient planning CT and contours are exported to Eclipse 11.0 and re-planned on Varian TrueBeamTM system (6MV beam, 2.5 mm HD 120 MLC, and 1 or 2 co-planar arcs). The 6 plans (3 CK plan and RapidArc plans) are compared with respect to dose uniformity, tumor coverage, conformality as well as the dose to the critical structures. The conformality of the plans is assessed using the ratio of the irradiated volume at 100%, and 50% of the prescription dose to the PTV volume (C100% and C50%). Treatment time, monitor unit (MU) per fraction and imaging doses are also compared with the conventional Varian RapidArc treatment. In order to estimate the CK imaging dose to the patient, dose measurements are performed using a RANDO head phantom with nanoDot™ OSLD dosimeters attached to the surface and inserted to the middle of the head phantom.

Results: Treatment plans that meet the clinical constraints are achievable on both systems. All the plans have PTV coverage above 95% with critical structures under RTOG 0539 dose limits. Over all, RapidArc plans are more uniform than CK plans. The prescription isodose lines for the 3 CK plans are within 80-84% compared with 86-90% for the RapidArc plans. All 6 plans are very conformal at prescription dose with C100% range from 1.1 to 1.6. C50% for CK plans are 5.6, 4.2 and 4.1 compared with 9.1, 7.8 and 5.8 for the three RapidArc plans. C50% decreases with increase in tumor size on both systems, however CK plans have smaller value at all three cases which means more conformal plans or faster dose drop off. The difference gets smaller with increase in target size. The MUs for the three CK plans are 1.8, 2.1 and 5.3 times higher than the RapidArc plans respectively. Estimated treatment time for three CK plans increases from 16 to 27 minutes with increase in target size. Imaging dose from a typical skull tacking (115 Kv, 100 mA, 100 ms) images is measured to be 0.3mGy/pair at entrance (45 degree away from anterior direction) and 0.1mGy/pair to the middle of the brain. In average, about 25 pairs of images will be taken in one fraction of treatment, resulting 7.5 mGy entrance dose (<0.5% of fraction dose) and 2.5 mGy brain dose per fraction.

Conclusions: Regular fractionated treatment is feasible with Cyberknife system for small volume tumors. Stereotactic delivery accuracy provided by CK IMRT leads to less margin on treatment volume, which is beneficial for lesions adjacent to critical structures. Dose from imaging guidance is found to be insignificant compared to the treatment dose. The CK plans are found to be more conformal compared with 1-2 co- planar RapidArc plans for small volumes (<30 cc), however, the dose in the target is less uniform (>5% hotter). Due to the increase in treatment time and MUs, the benefit of CK IMRT decreases with the increase in target size over 30 cc. This limitation may disappear with the introduction of M6 system with InCise Multileave Collimater which is capable to produce more uniform plans with significant reduced treatment time.

Poster 6 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric comparison of different external photon beam techniques to deliver accelerated partial breast irradiation 1De Martin E., 2Bonfantini F., 2Giandini T., 1Fumagalli M.L., 1Ghielmetti F., 3Lozza L., 3De Santis M.C., 3Franceschini M., 4Pinzi V., 4Fariselli L., 5Rampa M., 5Agresti R., 2Pignoli E. 1Health Department, Foundation IRCCS Neurological Institute C. Besta, 2Medical Physics Unit, Foundation IRCCS National Cancer Institute, 3Radiotherapy Unit 1, Foundation IRCCS National Cancer Institute, 4Radiotherapy Unit, Foundation IRCCS Neurological Institute C. Besta, Milan, Italy, 5Breast Surgery Unit , Foundation IRCCS National Cancer Institute

Objectives: Since June 2013 a new protocol for accelerated partial breast irradiation (APBI) has been established as a collaboration between National Cancer Institute and Neurological Institute C. Besta in Milan. Enrolled patients are treated using a CyberKnife (CK) system, and traditional linac Volumetric Modulated Arc Therapy (VMAT) and 3D Conformal Radiotherapy (3DCRT) plans are also optimized. Aim of this work is to compare these three different irradiation techniques for APBI.

Methods: Plans with Multiplan treatment planning system for CK, and Varian Eclipse for VMAT and 3DCRT, were generated for six early-stage left breast cancer patients. For all three techniques treatment volume was defined as CTV=GTV(tumor bed)+1.5mm. The PTV was then obtained expanding the CTV by 5mm. Prescription dose to the PTV was 30Gy in 5 fractions (6Gy/die). Number of beams and entry angles for the CK were produced via system software. 3DCRT plans consisted of two coplanar fields + two fields with treatment couch rotated by 90°, while for RA two coplanar arcs (+ 2 arcs with treatment couch rotated by 90° if necessary) were used. Conformity and homogeneity Index and dosimetric parameters from the DVHs were used to evaluate the differences in terms of PTV coverage and Organ At Risk (OAR) sparing among irradiation techniques.

Results: The mean dose to the PTV turned out to be the same with the three techniques with VMAT giving the best results in terms of homogeneity and the percentage of target volume receiving 90% of the prescribed dose (p<0.05). No significant differences were found for OAR sparing, although low doses to heart and contra-lateral lung were reduced with 3DCRT compared to CK and VMAT. The dose to ipsi- lateral breast, instead, increased with 3DCRT.

Conclusions: In this dosimetric comparison VMAT achieved the best PTV coverage results. However, in the treatment with CK, the organ motion is controlled and delivery accuracy is expected to be better than with 3DCRT and VMAT. Moreover, we plan to perform further dosimetric analyses considering PTV margin diversifications specific for irradiation technique.

Poster 7 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Validation of the Iris Quality Assurance Tool for a Cyberknife system A. Martinotti, M. Invernizzi, A. Bergantin, C. Vite, F. Ria , L. Bianchi, G. Beltramo Cyberknife Unit, Centro Diagnostico Italiano, Milan, Italy

Objectives: A regular spot check of Iris collimator aperture reproducibility is recommended for routine QA and the Iris QA Tool may represent a convenient mean for this check. It is a film-based tool and a faster and more automated method, alternative to the use of a water phantom (except during commissioning and after a major work on the device). Aim of this work is the validation of the Iris QA Tool and in particular the investigation of the acceptability range for the apertures of iris collimator and for the baseline definition.

Methods: We performed 10 repeated measurements in two weeks. Gafchromic EBT3 were placed into the dedicated phantom, irradiated and scanned according to the general prescriptions. Each time we performed 3 repeated measurements for each iris field size (5 mm excluded) and 4 measurements for 15 mm fixed collimator, to set each time the OD (optical density) threshold. First, to validate the Iris QA Tool reproducibility we calculated the SD of 10 measurements of the equivalent diameter for the 15 fixed collimator. Secondly, we verified the consistency of Iris apertures by determining the SD of the equivalent diameter for each collimator aperture from 7,5 mm to 60 mm. Thirdly, we developed a plugin which derives the FWHM of 12 profiles, taken at equally spaced angles around the centroid of a thresholded region, in order to check the iris intrinsic variability with an independent method.

Results: The SD of the profiles diameter for the 15 fixed collimator was 0,02 mm, confirming the validity of the Iris QA Tool, while the SD of the profiles diameter for each iris collimator size was about 0,14 mm (from 0,12 to 0,17 mm), with a mean variation of 0,38 mm (from 0,34 to 0,45 mm). Our plugin confirmed the results of Iris QA Tool, with a SD of about 0,14 mm.

Conclusions: The higher variability observed for iris collimator, calculated with the Iris QA Tool and confirmed with our plugin, shows that it has an intrinsic mechanical variability. Considering the range of the results obtained for iris apertures, it is not advisable to establish a baseline with one single measure, but it would be more appropriate to choose a mean of many measurements. In this way, we could accept differences up to 2 SD for constancy spot checks.

Poster 8 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric Comparison of Cyberknife with MLC versus Linac-based Intensity Modulated Radiation Therapy in Prostate Cancer Lane Hayes (Alliance Oncology), Jun Yang (Alliance Oncology, Drexel University), Colin Sims (Accuray), Joseph Rella (Alliance Oncology), Claire Y. Fung (Commonwealth Hematology Oncology)

Objectives: The recent development of a multileaf collimator (MLC) for Cyberknife has the potential of new clinical application in conventionally fractionated radiation therapy. This study offers a dosimetric comparison of intensity modulated radiation therapy (IMRT) plans using Cyberknife with MLC versus conventional linear accelerator (linac).

Methods: Ten prostate cancer patients treated with linac-based IMRT were selected with the prescription dose of 7920cGy at 180cGy per fraction. GTVs were defined as the prostate gland and proximal seminal vesicles and the PTVs were defined as GTV+8mm in all directions except for 5mm posteriorly. Conventional IMRT planning was performed on Philips Pinnacle 8.0m and delivered on a standard linac with cone beam CT and 10mm MLC leaves. For each case a Cyberknife plan was created using Accuray Multiplan 5.0 with the same CT data set, contours and dose constraints. All dosimetric data was transferred to a third party software for independent computation of the contour volumes and comparison of dose volume histograms. Delivery efficiency was evaluated using total monitor units (MU), treatment time, number of beam and number of segments.

Results: The average D95%RX for the PTV was 99.29 ± 0.78% for linac and 98.83 ± 1.44% for Cyberknife. The average D98%RX for the GTV was 99.98 ± 0.06% for linac and 99.82 ± 0.45% for Cyberknife. The homogeneity index (1.07 ± 0.01 for linac and 1.08 ± 0.02 for Cyberknife) and the new conformity index (1.28 ± 0.07 for linac and 1.25 ± 0.08 for Cyberknife) were comparable. The doses to critical structures for Cyberknife and linac plans were found to be statistically similar for all constraints except for rectum V50Gy and bladder V65Gy. The average bladder V65Gy was significantly lower for the Cyberknife (17.87% ± 12.74) versus linac (21.03% ± 11.93, p =0.0405). The linac plans utilized 9 coplanar beams, 48.9 ± 3.81 segments, and 19380.53 ± 2399.45 MU. The Cyberknife plans utilized 38.4 ± 8.98 non-coplanar beams, 85.5 ± 20.98 segments and 42554.71 ± 16381.54 MU. The average treatment time was 15.02 ± 0.6 minutes for linac versus 20.9 ± 2.51 minutes for Cyberknife.

Conclusions: The Cyberknife IMRT plans were comparable to the linac IMRT plans in meeting the target volume dose objectives. Critical structure dose constraints were largely comparable although statistically significant differences were found in favor of the Cyberknife in terms of rectum V50Gy and bladder V65Gy at cost of 25% longer treatment time.

Poster 9 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Helical Tomotherapy: our experience in treatment of Head and Neck cancer A.Grillo¹, R.Mazzola¹, M.Gueci¹, V.Gruppuso¹, M.Federico¹, L.Benvegna¹, L.Pollara¹, G.Ferrera², G.Mortellaro², T. Cucchiara², F.Sciumè², B.Abbate³ ¹Residency Program in Radiotherapy -University of Palermo-Italy, ²Department of Radiation Therapy -ARNAS “Civico-Palermo, Italy, ³Department of Medical Physics -ARNAS “Civico”-Palermo, Italy

Objectives: To report our initial experience of Helical Tomotherapy (HT), recently committed, in the treatment of Head and Neck Cancer (H&N) focusing on acute toxicity.

Methods: From Jenuary 2013 to December 2013 we treated 28 patients (pts) with head and neck cancer, 20 males and 8 females, median age 64 years (40-88) and evaluated for acute toxicity, analizing weight loss, xerostomia, dysphagia, mucositis and dermatitis. Nine pts presented rhinopharynx cancer, 6 oral cavity cancer, 5 larynx cancer, 4 oropharynx cancer, 2 salivary gland tumor, 2 unknown cancer neck metastases. All of them had locally advanced disease, 11 pts underwent adjuvant chemo-radiotherapy Cisplatinum-based (q21); 6 pts adjuvant radiotherapy and 11 pts exclusive radiotherapy +/-chemotherapy on primary tumor and positive neck nodes. Pts with rinopharinx and oropharinx cancer underwent simultaneous integrated boost (SIB) in 30-33 fractions at a dose of 2.12Gy to the PTV to a total dose of 69.96Gy while 1.8Gy to 59.4Gy in high risk nodes, 1.64Gy to 54.12Gy in low risk nodes. Pts with oral cavity, larynx, salivary gland tumor, unknown cancer neck metastases underwent conventional fractionation scheme. Acute toxicity was evaluated using EORTC-RTOG toxicity scale at 1 month and 3 months. Daily megavoltage CT was performed in each patient. To limit xerostomia and to get the best possible quality of life, attention was paid during planning to achieve a mean dose to parotid glands ≤ 26Gy.

Results: OAR doses were respect easily in almost every patient due to high dose conformity allowed by HT, but correct contouring remains still critical. 22-24 Gy average planning dose was reported for parotid glands. Median follow up was 7 months. Four pts interrupted treatment for 7 days, 2 for pancytopenia, the others for reasons not related to radiation treatment. Image-guided (IGRT) allowed to record mismatching in 3 pts due to loss of weight and re-simulate them at second week of treatment. No pts developed grade>2 of mucositis, dysphagia, xerostomia or dermatitis. At 1 and 3 months 15 pts presented G1-G2 xerostomia, 18 pts G1-G2 dysphagia, 15 pts G1-G2 mucositis

Conclusions: HT seems to have the same encouraging grade of acute toxicities compared to other kind of IMRT as reported in literature. Long term data for HT are needed to definite long term effects. We expect a better local control and lower local failure and adverse late events

Poster 10 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Frameless fractionated stereotactic radiotherapy (FSRT) for brain metastases using helical tomotherapy: clinical outcomes James C Marsh, M.D. Vershallee Shukla, M.D. 21st Century Oncology of Arizona 14506 W Meeker Blvd, Sun City West, AZ 85375

Objectives: To report the clinical outcomes for brain metastases treated with frameless fractionated stereotactic radiotherapy (FSRT) using helical tomotherapy.

Methods: We treated 54 intracranial metastases in 24 patients to a total dose of 21-30 Gray (Gy) in 2-5 fractions (biologically equivalent dose [BED 27-30 Gy10] . Targets were defined using gadolinium enhanced cranial MRI fused to planning cranial CT. Gross tumor volume (GTV) = enhancing tumor on MRI T1 post-contrast sequence. PTV = GTV + 2mm radial expansion. Thermoplastic mask was used for immobilization. Megavoltage CT was obtained with each fraction for target localization. No more than 3 fractions were given in any calendar week. 11/24 patients had received prior whole brain radiotherapy (WBRT), whereas 13/24 received FSRT alone.

Results: With median follow up of 13.5 months local control for treated lesions was 96.3% (52/54), elsewhere central nervous system (CNS) progression rate was 25% (6/24), CNS death rate was 8.3% (2/24), systemic progression rate was 29.2% (7/24), overall survival (OS) was 87.5% (1 year OS 91.7%), progression free survival (PFS) was 50% (1 year PFS 54.2%), and radionecrosis incidence was 1.9% (1/54). No other grade 3 or higher toxicity was noted.

Conclusions: Frameless FSRT using helical tomotherapy with daily MV CT imaging for localization provides local control and survival rates at one year that compare favorably to other stereotactic techniques, and despite the lack non-coplanar beam capability yields very low rates of radionecrosis.

Poster 11 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Overcoming Reimbursement Limitations When Utilizing 3D Conformal Tomotherapy for Adjuvant Breast RT Quan Chen, PhD, Constance Geesey, CMD, and Shiv R. Khandelwal, MD UVA Department of Radiation Oncology and Culpeper Regional Hospital

Objectives: 3D conformal tomotherapy is new and clinical experience is limited. Newer tomotherapy units are equipped for 3D conformal radiotherapy (3DCRT) in order to address clinical situations where IMRT is considered unnecessary and its use restricted due to differential costs of IMRT vs. 3DCRT in the US. Breast cancer is the most common clinical indication affected as evidenced by ASTRO’s recent Choosing Wisely announcement that IMRT should not be used routinely to deliver whole breast RT (1). In our experience at a rural center since 2010 equipped only with tomotherapy, we have found 3D conformal tomotherapy to be an excellent option in many situations due to its inherent 3D tissue compensation. However, 3D conformal tomotherapy is problematic for breast RT due to lack of beam weighting, beam’s eye view block design, or trial comparisons, inability to constrain dose outside the PTV in 3DCRT modes, being limited to a relatively soft 6 MV beam, and inability to manage motion. Therefore, we have needed inverse IMRT for many breast cancer patients who would not require IMRT if treated on a fixed gantry linear accelerator. Our purpose is to explain the workflow we have developed to ensure proper reimbursement when using tomotherapy to administer adjuvant breast RT and to propose policy solutions aimed at simplifying this workflow.

Methods: As illustrated in the flowchart, all breast cancer patients requiring adjuvant RT following lumpectomy have undergone attempted planning with3D conformal tomotherapy, usually in static beam mode with tangential fields. When such planning was deemed unsuccessful because of dose inhomogeneity or dose to organs at risk, IMRT medical necessity was documented and insurance preauthorization requested. In order to avoid delays in treatment, IMRT planning was initiated prior to receipt of IMRT insurance preauthorization.

Results: To this point, the illustrated workflow has prevented us from utilizing IMRT without authorization. Developing an acceptable 3DCRT plan has been more difficult when trying to utilize the “Canadian hypofractionation” schedule. We have not yet had to refer patients to other facilities, but in a few cases this has required peer-to-peer review. In some cases, insurers have acquiesced to IMRT only because there are no nearby competing facilities. The illustrated workflow is labor-intensive and does not generate additional relative value units despite the extra effort required. The consensus amongst our staff is that we would prefer to remove the 3DCRT planning step from the process and instead utilize all of tomotherapy’s tools to develop a high quality IMRT plan and accept 3DCRT reimbursement for those cases that would have only required 3DCRT if treated on most other units. We have successfully made this argument to our two largest insurers and plan to pursue similar permission from all the major insurers in our region.

Conclusions: While the illustrated workflow ensures IMRT medical necessity is demonstrated, we believe, given the limits of 3D conformal tomotherapy for breast RT, blanket permission to down code breast IMRT on tomotherapy to 3DCRT will simplify our workflow and is the best option for patients, insurers, and for our staff.

Poster 12 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Bilateral Breast Irradiation: Tomo Versus 3D-CRT Siji Nojin, Ph. Reena, Nara M., W. Tabassum, R. Sarin. ACTREC, TMC

Objectives: This study compares the dosimetric results of 3D-CRT with Helical Tomotherapy plans for bilateral breast irradiation.

Methods: Here we are intending to dosimetrically compare the conventional tangential beam treatment using 6 MV beam of PRIMUS (Siemens LINAC) with that of HI-art Tomotherapy unit for bilateral breast irradiation. For comparison we planned 5 patients involving either bilateral breast or breast and chest wall combination with a prescription of 50Gy in 25 fractions. The planning CT of 3mm slice thickness was taken and structures viz, PTV, lungs and heart were contoured. The first arm i.e. the 3D-CRT was planned in Oncentra Treatment Planning system (version 4.1).Aim was to achieve at least 90% dose coverage in 90% of the target volume for a bilateral summed plan. The coverage was compromised if the high dose volume of 110% exceeded 2%. The second arm i.e. tomotherapy plans were planned on Tomotherapy Planning system (version 4.2.1) to achieve comparable coverage with a 5 cm field width and 0.3 pitch. The highest acceptable value of modulation factor was set to be 3 and the beams from the posterior direction were blocked. Both the plans for each patient were compared for coverage and homogeneity of their respective targets as well as relevant dose volumes of the organs at risk (OAR). Heart and both the lungs were identified as OARs. Volume of heart receiving 13 Gy and 30 Gy and volume of each lung receiving 5Gy, 10Gy and 20Gy as well as their mean doses were considered relevant. For better understanding the volumes for each respective dose was compared between the conventional and tomoplans by subtracting the tomo dose volume from the corresponding conventional dose volume. A positive output would mean the dose volume for conventional plan is greater than that for tomoplan.

Results: The coverage and homogeneity of tomotherapy plans were found to be better than that of 3D-CRT plans. The mean Homogeneity index for tomoplans was 0.2 ±0.04 and that of 3D-CRT plans was 0.59±0.34. Conformity index for tomoplans varied about the value 0.82±0.16 and for 3D-CRT plans it was 0.49±0.30. Also the volumes receiving 107% of the prescribed dose in tomoplans were around 2.48±2.61%, while that in conventional was 11.51±9.58%. The 110% volume was evaluated as 0.14±0.25% for tomotherapy plans while for the tangential plans the values were around 3.48±6.11%. Further the OARs were analyzed as follows: Lungs: The 20Gy, 10Gy and 5Gy volumes between both the plans were comparable. The differences in the tomotherapy plans versus conventional plans were in the range 5.39±3.15, 1.86±3.03 and 4.07±0.68 for left and 3.74±2.52, -0.3±5.82 and -1.95±7.74 for right lungs corresponding to 20Gy, 10Gy and 5Gy dose respectively. The mean doses were also comparable. Heart: Cardiac sparing in tomo proved to be better than in conventional plans. The difference in values for 30Gy, 13Gy and mean dose was in the range of 6.89±4.94, 3.27±3.46 and 3.03±6.01. Treatment time for tomotherapy was in the order of 5.32±0.3 mins while that for conventional it would come in the order of 3 mins.

Conclusions: We were able to achieve comparable plans with tomotherapy along with an advantage of increased PTV coverage. Even though the treatment time is greater than that for conventional, it can be considered as an option for bilateral breast irradiation.

Poster 13 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

TomoTherapy treatment of moving lesions: a phantom study Pallotta S1,2, Marrazzo L2, Livi L1,2 and Bucciolini M1,2 1Department of Experimental and Clinical Biomedical Sciences- University of Florence- Italy 2AOU Careggi Florence Italy

Objectives: Treatments performed with TomoTherapy on moving lung lesions might be inaccurate due to the simultaneous gantry rotation, patient couch translation and lesion movement. In this study the outcome of how these factors interplay and their effects on dose distribution are explored using a moving phantom and GafChromic EBT3 films. The use of Average Intensity Projection (AIP) CT images, adequate for dose calculation in most circumstances, is also explored.

Methods: A phantom made of clay lumps embedded in two adjacent polystyrene slabs, slid in a cranio- caudal direction using a motor-driven motion platform (3cm and 16cycle/min movement extension and rate). A Philips BigBore CT scanner was used to acquire 4DCT images of the moving phantom and to reconstruct AIP images. An image of the phantom in a static state was also acquired. The two data sets (AIP and static) were sent to the TomoTherapy planning station, a PTV was defined and plans for delivering 2Gy to the central clay lump in static and dynamic states were prepared. A field width of 1cm was used in both cases. The phantom was put on the patient couch, a GafChromic EBT film was inserted between the two polystyrene slabs and the treatment was delivered. The procedure was performed both for the static and moving phantom.

Results: A significant difference between planned and delivered dose distributions was observed in the moving phantom. The comparison between static and dynamic dose distributions shows under dosages (up to 4%) and over dosages (up to 50%) in the target region and surrounding regions, respectively. The over dosage effect is more pronounced in caudal direction. The most evident effect on dose distribution was dose blurring: the region receiving 50% of the maximum dose is 40% wider. This effect also impacted dose gradients which tended to decrease in the peripheral region.

Conclusions: Treatments performed with TomoTherapy on moving targets showed a significant difference between planned and delivered dose distributions when AIP CT images are used. Contouring strategies that keep into account these effects should be explored.

Poster 14 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Recurrent Head & Neck Cancer SBRT: Retrospective Outcome Analysis Ajmel Puthawala MD, M. Munir Muniruzzaman PhD, Nisar Syed MD, Joel Cherlow MD, Steven Damore MD, Asif Harsolia MD, Linda Chan MD, Bouchaib Rabbani PhD Orange County CyberKnife and Radiation Oncology Center

Objectives: To evaluate side effects, local disease control and outcome of recurrent Head and Neck Cancer treatment using the CyberKnife® Robotic Radiosurgery System.

Methods: We report here the retrospective analysis of 20 Head and Cancer patients treated between 2009 and 2013 at Orange County CyberKnife & Radiation Oncology Center. All patients were treated for Head and Neck Cancer with standard External Beam Radiation, but later developed local recurrence. The SBRT demonstrates to be a promising strategy to treat recurrent Head and Neck cancers. With sub-millimeter targeting accuracy, CyberKnife presented to be the ideal tool to treat the recurrent cancers. PET/CT and/ or MRI were fused with planning CT to delineate the target and critical structures. The target volumes were tracked in real time during treatment either by Xsight spine tracking or fiducial tracking, depending on the location of the tumor. Patients were treated on alternate days instead of standard daily treatment schemes. Patients received 30 to 40 Gy in 5 fractions.

Results: Two patients developed ulceration in the mouth which gradually improved over time. This led us to use more lateral beams than perpendicular beams when possible. No appreciable adverse effects were observed in other proximal critical regions such as larynx, spinal cord or esophagus. Excellent local control was achieved for the recurrent Head and Neck SBRT with CyberKnife. 6 month follow-up imaging showed diminishing or stable tumor volume.

Conclusions: Retrospective study of the recurrent H&N cancer demonstrates that the SBRT with CyberKnife can be a promising strategy for local control. The excellent tumor tracking mechanism and sub-millimeter targeting accuracy of CyberKnife enables steep dose gradient and thereby allowing to deliver significant dose without compromising the dose tolerance to critical volumes during re-radiation.

Poster 15 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Exit-detector based dose reconstruction as a supplement for TomoTherapy IMRT QA Mark Geurts, MS University of Wisconsin-Madison

Objectives: A technique was developed to analyze the exit-detector response for patient specific IMRT QA, compute the actual leaf open times during QA delivery, and recalculate the treatment plan dose based on these leaf errors. A sensitivity analysis was performed to validate this technique against conventional IMRT QA methods.

Methods: Patient plans were modified to introduce MLC delivery errors. Delivery quality assurance was conducted on the baseline and modified plans using the ScandiDos Delta4 diode array phantom, and repeated with the exit-detector based technique.

Results: Sensitivity tests indicate that the exit-detector test is as sensitive as current IMRT techniques for detecting MLC based delivery errors. This technique provides additional capability to determine the clinical impact of these errors by recalculating the planned dose, offering the potential for patient specific pass/fail metrics. However, issues exist for dynamic jaw plans.

Conclusions: IMRT quality assurance using exit-detector techniques is a viable and efficient supplement for conventional methods, particularly for extended fields commonly treated by TomoTherapy.

Poster 16 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Total Skin TomoTherapy for Treatment of Mycosis Fungoides Mark Geurts MS, Adam Bayliss PhD, Geoff Nelson PhD, and Bishnu Thapa PhD University of Wisconsin Madison

Objectives: A patient at the University of Wisconsin presented with chemotherapy refractory T cell lymphoma of the skin. Unfortunately, due to the severity of disease the patient would not have been able to stand for a conventional technique of using electrons. Therefore, a TomoTherapy plan was developed.

Methods: Pre-planning phantom studies were conducted to compare superficial dose, depth falloff, and patient integral dose between TomoTherapy and the modified Stanford technique.

Results: Gafchromic film measurements confirmed similar dosimetry between techniques. Patient setup errors were also simulated to evaluate plan robustness and indicate up to 1 cm errors can be reasonably tolerated. Finally, a patient plan was developed, evaluated using a novel exit detector quality assurance technique, and delivered to the patient. TLD measurements placed on the patient confirm a satisfactory surface dose was delivered.

Conclusions: In conclusion, the methods developed for this plan indicate this technique can be used to complement conventional electron techniques and provide improved superficial dose homogeneity and patient comfort.

Poster 17 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Image guided hypofractionated radiotherapy with simultaneous integrated boost with helical tomotherapy for definitive treatment of prostate cancer: preliminary results on acute outcomes. G. Mortellaro2, A. Spera1, G. Ferrera2, F. Sciumè2, M. Bono2, T. Bruno1, G. Caminiti1, A. Grillo1, V. Figlia1, M. Gueci1, D. Messana2 1 University of Palermo, Radiotherapy Unit, Italy. 2 ARNAS-Civico, Radiotherapy Unit, Palermo, Italy

Objectives: To evaluate preliminary acute toxicity in patient with prostate cancer treated with Hi Art Helical Tomotherapy (HT) recently commissioned in our department of South Italy.

Methods: We reviewed 38 prostate cancer patients treated in our department with definitive approach from January to September 2013. Patients were stratified according to the NCCN classification in low risk (14 pts.), intermediate risk (7 pts.) and high risk (17 pts.). 24 patients underwent androgen deprivation therapy (ADT) according to urologist’s indication. Treatment was performed using HT with daily megavoltage CT images delivering a simultaneous integrated boost (SIB); Different clinical target volumes (CTVs) were defined: CTV1 prostate, CTV2 seminal vesicle and CTV3 pelvic node. We irradiated CTV1, CTV1+CTV2 and CTV1+CTV2+CTV3 in low, intermediate and high risk patients respectively. An expansion of 1 cm in all directions except 6 mm for posterior border was performed to create planning target volumes (PTVs). We delivered 2.5 Gy/die to PTV1, 2.2 Gy/die to PTV2 and 1,8 Gy/die to PTV3 simultaneously in 28 fractions for a total dose of 70 Gy to PTV1, 61,6 to PTV2 and 50,4 to PTV3. All high risk patients underwent pelvic irradiation. Acute toxicity was recorded and graded according to Radiation Therapy Oncology Group (RTOG) criteria.

Results: All patients completed planned HT treatment; with a median follow-up of 7 months (3-11) no patients experienced G3 or G4 acute gastrointestinal (GI) or genitourinary(GU) toxicity; acute G2 GU toxicity was observed in one patient and G1 in 16 patients. Regarding GI score, G2 toxicity occurred in one patients and G1 in four patients. We didn’t report any kind of relationship between GU and GI toxicity with whole pelvic irradiation.

Conclusions: These preliminary data suggest that HT treatment for definitive moderate Hypofractionation treatment of prostate cancer is feasible and safe even if further evaluation and longer follow up are necessary to assess late toxicity and tumor control.

Poster 18 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Image Guidance Options for Prostate Cancer Patients Slav Yartsev (a) and Tomasz Piotrowski (b) (a) London Regional Cancer Program, London Health Sciences Centre and Western University, London, ON, Canada; (b) Department of Medical Physics and 2nd Radiotherapy Department, Greater Poland Cancer Centre, Poznan, Poland

Objectives: To analyze systematic and random errors obtained from the pooled data on inter-fraction prostate motion during radiation therapy in two cancer centers and to evaluate different options of limited image guidance.

Methods: Position correction shifts obtained by co-registration of planning kilovoltage and 6085 daily megavoltage CT studies for 216 prostate cancer patients treated on tomotherapy Hi-ART units in London, ON, Canada and Poznan, Poland were investigated. Three independent variables: patient position (supine or prone), target (prostate or prostate bed), and megavoltage CT imaging mode (normal or coarse) were analyzed using statistical methods for the pooled data [1]. Systematic and random errors were evaluated and used to calculate the inter-fraction position uncertainty components to the planning target volume (PTV) margins for different options of referencing based on the position corrections observed with one, three, or five imaging sessions.

Results: Statistical analysis showed that only the difference between normal and coarse modes of imaging was significant, which allowed to merge the supine and prone position sub-groups as well as the prostate and prostate bed patients. In the normal and coarse imaging groups, the PTV margins calculated using systematic and random errors in the medio-lateral and cranio-caudal directions (5.5 mm and 4.5 mm, respectively) were similar, but significantly different (5.3 mm for the normal mode and 7.1 mm for the coarse mode) in the anterio-posterior direction.

Conclusions: The normal (4 mm) mode of the helical tomotherapy megavoltage scans performed during the treatment of patients with prostate cancer was shown to produce smaller systematic error in anterior- posterior direction compared to the coarse (6 mm) imaging mode. Based on this study, the referencing scheme based on the first three fractions can be recommended.

[1] Piotrowski T, Rodrigues G, Bajon T, Yartsev S, Method for data analysis in different institutions: Example of image guidance of prostate cancer patients. Physica Medica (in press), DOI: 10.1016/j. ejmp.2013.05.001 (2013).

Poster 19 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Review of Clinical Accuracy Analysis for Robotic Radiosurgery Blanck O 1,2, Schweikard A 3 1University Clinic Schleswig-Holstein, Lübeck, Germany 2CyberKnife Center Northern Germany, Güstrow, Germany 3University of Lübeck, Institute for Robotics and Cognitive Systems, Germany

Objectives: The robotic CyberKnife (Accuray, USA) is a highly precise radiation treatment system. The sub-millimeter (<1mm) phantom accuracy of the system has been demonstrated and proven in many studies however, only limited studies regarding delivery accuracy under real clinical conditions exist. We therefore reviewed available clinical delivery accuracy studies for the CyberKnife and completed the review with our own studies performed in the past. Based on the available data we wanted to give further suggestions on future studies and potential improvements for the CyberKnife system.

Methods: For each current CyberKnife tracking modality (6DSkull, XSight Spine, Prostate Fiducial, Lung Synchrony, Lung Optimized Treatment with XSight Lung, Liver/Abdomen Synchrony) we performed a literature research (PubMed, RSS, AERO) also for related stereotactic radiosurgery (SRS) or body radiation therapy (SBRT) treatments and completed the data with our own studies. Only 7 paper and 6 presentations from various congresses were deemed suitable for clinical delivery accuracy estimation of the CyberKnife. 10 studies were based on patient log File analysis whereas only 3 used the log files to re-calculate the dose, 2 studies explored in vivo dosimetry systems during treatment and only 1 study looked at differential target to fiducial motion.

Results: The accuracy for brain and spine tumor treatment with adequate imaging frequency and despite intra-fraction patient motion seems to be below 1mm or 2% coverage drop. However, when treating eye tumors fractionated daily re-planning may be necessary in more than 40% of the cases. The accuracy for prostate treatments seems to be below 3mm without and below 1mm with rotation tracking to maintain the planned target dose coverage. For stationary targets the reduction of x-ray imaging during treatment seems therefore to be the current focus of research. Accuracy estimation for moving targets necessitate the errors be divided into correlation (target-fiducial-chest), prediction (robot latency) and not compensated (deformation and rotation) errors. The first and second can be assessed from system log files, the last only estimated due to current lack of real time treatment data. The correlation error for lung and liver treatment strongly depends on fiducial-target distance, feature extraction accuracy and quality of surrogate signals, but seems to be below 3mm. However, the correlation model may change every 10-30 minutes. The prediction accuracy seems to be below 1mm, but could further be improved by newer prediction algorithms. The estimated or measured in vivo overall dosimetric accuracy may range between 10-15% in a single point in some cases and careful patient alignment the presents of strong breathing dependent organ rotation and deformation is required. These errors cannot be simulated before treatment due to differences in patient breathing during planning CT and treatment which is also the reason why delivery accuracy estimation for lung optimized treatment which uses 4DCT to generate margins is currently not possible. Real time data i.e. using video, implanted transponders, ultrasound or MRI may overcome these issues which may also enable adaptive (real time) dosimetry and treatment planning.

Conclusions: While the local tumor control after high dose CyberKnife SRS or SBRT is generally high (>90%) as reported in numerous publications the real clinical delivery accuracy especially due to unavailable target and critical structure real time motion data remains unclear. New non-ionizing real time imaging may finally introduce a means to establish the real clinical delivery accuracy of CyberKnife treatments and are being under current investigation. Furthermore, detailed clinical response analysis i.e. on MRI after liver SRS/SBRT may also enable the clinical accuracy estimation. Based on the available data a margin of 1-2mm

Poster 20 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

for stationary targets and 3-5mm for moving targets seems to be sufficient to cover delivery inaccuracies, yet errors in imaging, fusion, contouring and dose calculation have not been reviewed and may need to be considered as well when generating safety margins for CyberKnife treatments. To reduce these margins and hence to increase the CyberKnife accuracy careful patient alignment protocols, real time log file analysis and adaptation, newly developed prediction and correlation algorithms and the integration of real time imaging into the CyberKnife may be implemented in the future.

Poster 20 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

A phase II study to evaluate the efficiency and safety of locally advanced pancreatic adenocarcinoma treated with CyberKnife SBRT Ping Wang, Yongchun Song, Zhiyong Yuan, Yang Dong, Fengtong Li, Jingsheng Wang CyberKnife Center of Tianjin Cancer Hospital

Objectives: Stereotactic body radiation therapy (SBRT) has emerged as a potential treatment option for local tumor control of primary malignancies of the pancreas. We report on our experience with CyberKnife® SBRT in patients with locally advanced pancreatic adenocarcinoma.

Methods: We reviewed our 26 patients who receiving CyberKnife® SBRT for locally advanced pancreatic adenocarcinoma from 2007-2012. Prior to SBRT, three cycles Gemcitabine chemotherapy was given, then at least 1 gold fiducial marker were placed within or around the tumor through percutaneously under BUS-guidance to allow for tracking of tumor during therapy. The prescribe dose was 45 Gy delivered over 5 fractions. Then chemotherapy with Gemcitabine was given until toxicity or progression.

Results: The mean gross tumor volume before SBRT is 43.6 cm3 (range 15.2-148 cm3). Median survival time was 12 mo (range 4-49 mo). The probability of overall survival at 12 and 24 mo were 50% and 35%. No patient had a complication related to fiducial markers placement. The rate of radiation induced adverse events was: grade 1-2 (88%, n=23) and grade3 (4%, n=1). There were no grade 4/5 adverse events seen.

Conclusions: Our preliminary results showed CyberKnife SBRT has favorable OS comparable to conventional regimens, and the acute/late toxicity is minimal. CyberKnife can be a safe and likely effective local treatment modality for locally advanced pancreatic adenocarcinoma.

Poster 21 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

The research on the factors affecting the passing rate of TomoTherapy DQA Qi Yue, Ji-Mei Duan, Zhi-Wei Wang, Dan Gu, Xiu-Mei Yang , Rong-Qing Li First Affiliated Hospital of Kunming Medical University

Objectives: The purpose of this article is researching on the factors of effecting the passing rates of TomoTherapy DQA ,and analyzing the reasons which cause the failing of DQA.

Methods: Measuring the Gamma passing rates of the ArcCheck device with manually introduced errors in TomoTherapy DQA. The errors include setup errors in LR,SI,AP directions, the gantry angle error, calculating the dose in the phantom with wrong IVDT, low dose rate. All the results with errors were compared with the results errors free under the 3%/3mm and 2%/2mm Gamma criteria. The effect of the accuracy in the application of kilovoltage computed tomography (KVCT) and mega-voltage computed tomography (MVCT) images on the delivery quality assurance (DQA) in helical tomotherapy (HT) was also analyzed.

Results: When the errors were introduced to the TomoTherapy DQA, the Gamma passing rate dropped under the 3%/3mm and 2%/2mm Gamma criteria, the Gamma passing rate dropped more significantly under the strict 2%/2mm Gamma criteria. There is no statistical significance for the Gamma passing between scanning the ArcCheck phantom with the KVCT and MVCT under the 3%/3mm and 2%/2mm Gamma criteria.

Conclusions: The results confirmed the feasibility of using the Gamma method to investigate small delivery and setup errors. The errors of the setup position and machine paraments can lead to the dose delivery errors in TomoTherapy, the quality assurance of machine and plan should be enhanced to minimize the dose errors. A feasible DQA strategy may be the combined use of strictly Gamma criteria as 2%/2mm. The results also showed that there is no difference of KVCT image and MVCT image on the delivery quality assurance (DQA) in helical tomotherapy.

Poster 22 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Workflow optimization for CyberKnife treatments F. Crop (1), T. Lacornerie (1), X. Mirabel (2) and E. Lartigau (2) 1 Medical physics, Centre Oscar Lambret and Université Lille 1 2 Department of radiation therapy, Centre Oscar Lambret and Université Lille 2

Objectives: The goal of this study was workflow and machine utilization optimization of the CyberKnife (CK). CK utilization is suboptimal in a classical scheduling environment due to the presence of (a) large variability in preparation time, (b) variable treatment time, only known just before treatment (especially for liver and lung treatments), and (c) a high rate of cancellations. Moreover, this leads to a high perceived stress load for all personnel. Especially liver and lung treatments with synchrony can create very difficult schedules.

Methods: The organization was analyzed using Operations Research techniques and optimized using Industrial engineering techniques. A Discrete Event Simulation model of the organization was programmed and modeled in SimPy (Python): SimCK. This simulation model was ideal for testing and optimizing different organizations without intervening on patient flow.

Results: We present a different organization method, a hybrid CONWIP (Constant Work In Progress) system utilizing normalized work: managing normalized work in progress instead of scheduling all steps. The SimCK simulation model was used to optimize organizational parameters. After implementation, we obtained an increase in output of 28% [20%,36%] (95% CI, 18 months) for the CyberKnife installation, with a negligible increase of time between CT and treatment and an improved perceived stress load for personnel.

Conclusions: Industrial Engineering is common in industry, but not in healthcare, as “patients are not cars”. Application of common techniques used in industry can modify organizations considerably without turning patients into cars. With a mix of liver (21%), lung (29%), intracranial (13%),head and neck (11%), and prostate (7%) patients, we arrive at +500 patients/year, +2100 fractions/year output and better personnel stress levels.

Poster 23 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

Dosimetric comparison of Cyberknife and Helical Tomotherapy Radiosurgery for single brain metastasis Daniela Greto1, Stefania Pallotta1, Laura Masi2, Cinzia Talamonti1, Raffaella Doro2, Livia Marrazzo1, Silvia Scoccianti1, Icro Meattini1, Pierluigi Bonomo1, Lorenzo Livi1 1Radiotherapy Unit, University of Florence, Florence, Italy 2Radiotherapy Unit, IFCA, Florence, Italy

Objectives: CyberKnife System is a robotic radiosurgery system that delivers stereotactic radiosurgery non- invasively. Its ability to track and automatically correct tumor motion during treatment enables delivery of high doses of radiation with extreme accuracy. Helical Tomotherapy (HT) combines intensity modulated fan-beam radiotherapy delivery with Megavoltage Computed Tomography (MVCT) imaging for integrated patient positioning and treatment delivery. The aim of this study is to perform a dosimetric comparison of Cyberknife (CK) and Helical Tomotherapy (HT) stereotactic radiosurgery for the treatment of single brain metastasis.

Methods: Fourteen patients with brain metastasis for a total of nineteen lesions treated with Cyberknife were planned for single fraction radiosurgery using the Tomotherapy Hi-ART system. Dosimetric parameters such as Conformity Index (CI), Homogeneity Index (HI) , Gradient Index (GI) and beam on time were analyzed.

Results: Cyberknife can achieve a good target coverage (Coverage = 98.91 ± 1.26) , a high level of conformity (CI = 1.06 ± 0.03) .The Cyberknife gives low doses to surrounding healthy tissues (Mean GI = 3,62; p=0.0001) at the cost of a mean treatment time of 33.21 min (p=0.0001). Tomotherapy can achieve similar level of target coverage (Coverage=97.33± 1.99) but it realized more low doses outside the PTV (GI = 5,07; p=0.0001) and consequently a higher conformity index (mean CI = 1,25; p=0.001). The Tomotherapy mean treatment time was 17.84 min, significantly shorter than CyberKnife (p=0.0001). Cyberknife and Tomotherapy have both an inhomogeneous dose distribution inside PTV (HI = 1.25 ± 0.00 and HI=1.28 ± 0.05 , respectively ).

Conclusions: Cyberknife and Tomotherapy are two modalities that will comply with the high conformity SRS constraint but the non-isocentric beams (Cyberknife) will spread less low-dose than the helical delivery (Tomotherapy) at the cost of treatment time. Multiple focal entries (Cyberknife) will achieve better conformity than Tomotherapy. Both modalities results in inhomogeneous treatment with an excellent target coverage.

Poster 24 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

The CyberKnife® Coalition: Advocating for Patient Access Officers: Linda Winger, President, Don Fuller MD, Secretary, Gregg Dickerson MD, Treasurer Board of Directors: Tori Shannon, Mark Perman MD, Debra Freeman, MD, Greg Spurlock, Jim TeWinkle, James Schwade, MD, Mark Brenner, MD, Lynn Kuhn, John Rieke, MD

Introduction: Formed in May 2003 and incorporated in April 2005, the CyberKnife ® Coalition (CKC) is a non-profit [501(c) 6] association of CyberKnife user physicians and institutions, dedicated to protecting patients’ access to this life-saving technology. Since its inception the CKC has supported efforts to collect and develop data demonstrating the therapeutic, quality of life, and economic benefits of CyberKnife treatments and has worked collaboratively with payers to develop appropriate coverage, coding, and payment.

Objective: To ensure that both The Centers for Medicare and Medicaid Services (CMS) and private payers support continued patient access to this important, clinically proven and life-saving technology by: improving and protecting Medicare Hospital Outpatient payment, continued advocacy for improving reimbursement for Freestanding Centers, protecting Medicare prostate cancer coverage in states where draft policies threaten to withdraw coverage and overturning negative policies already in place, focused efforts with some commercial payers, organized responses to major evaluation body assessments and CMS proposals.

Methods: Patient Advocacy - strong partnerships with cancer survivors and patient support groups who believe in advocating for access to CyberKnife treatment for themselves and others; Physician Engagement and Mobilization - Physicians who recognize the importance of advocating for expanded patient access regardless of the geography or site of service; Media Involvement - leveraging the media to shine a light on harmful policies that hamper innovation and limit patient access to innovative technologies; Congressional Outreach - calling upon members of Congress to prevent or reverse policies that threaten patient access, cost jobs, and waste taxpayer money.

Results: Reversal of 3 Medicare non coverage policies for prostate in place in 18 states, Overturning draft policies of non coverage in 4 Medicare regions in 12 states and the District of Columbia. Some Medicare contractors provided coverage outright with certain criteria; more reluctant payers conceded coverage through “Coverage with Evidence Development” with registry.

Conclusions: This poster focuses on the efforts by the CKC to protect prostate cancer patient access to CyberKnife treatment. Through coordinated advocacy the CyberKnife Coalition has been successful in protecting or obtaining Medicare prostate cancer coverage in all 50 states and the District of Columbia. Other successful efforts of the CKC have resulted in: obtaining appropriate Medicare payment for Freestanding Centers at or near Hospital rates in over ½ the United States, obtaining coverage for other intra- and extracranial indications such as trigeminal neuralgia, multiple brain mets, and cancers of the liver, adrenal gland and pancreas; commercial payer coverage of prostate cancer with 1 large national payer and several regional Blues. We have included a limitations section in this poster to bring awareness to the challenges facing the radiosurgery community. The effectiveness of the CKC is limited when lacking participation and broad-based support. We encourage all U.S. based CyberKnife facilities to join the CKC to protect patient access to this innovative technology.

Poster 25 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014

NOTES SECTION The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 The Frontiers of Image-Guidance: Margins, Motion & Adaptation Wednesday, May 7, 2014 Precise, innovative tumor treatments™