Netic Resonance Imaging

CANADIAN MEDICAL PHYSICS NEWSLETTER Le BULLETIN CANADIEN InterACTIONS de PHYSIQUE MÉDICALE

Detection of Lung Remodelling following Radiation Therapy using Hyperpolarized 3He Mag- netic Resonance Imaging

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A publication of the Canadian Organization of Medical Physicists and the Canadian College of Physicists in Medicine http://www.medphys.ca

ISSN 1488-6839

56 (3) juillet/July 2010

PTW AD ALREADY UP- LOADED

70 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale InterACTIONS Volume 56, Number 3– juillet/July 2010

73 Message from the COMP President— Peter McGhee 74 Message from the CCPM President— Dave Wilkins 75 Message from the Executive Director— Nancy Barrett 76 CNSC Feedback Forum— Submission of Annual Compliance Reports Kavita Murthy, Director 77 Feature Article: Detection of Lung Remodelling following Radiation Therapy using Hyperpolarized 3He Magnetic Resonance Imaging L. Mathew, S. Gaede, A. Wheatley, R. Etemad-Rezai, G. Rodrigues and G. Parraga 79 Coeff6 – A Tool for Radiation Physics — Jack Cunningham 80 Book Review: Clinical Dosimetry Measurements in Radiotherapy—Alasdair Syme 85 Report of the 2009 Harold E. Johns Travel Award Visit Hyperpolarized Gas Magnetic Resonance Lung Imaging at the Robarts Research In- stitute in London, Ontario — Dr. Atiyah Yahya 88 Laptops for Kenya — Marija Popovic 89 NSERC opening up for Medical Physics — David W O Rogers and William Whelan 91 Interesting Things Medical Physicists Do: Swords into Ploughshares?! — Alex Vitkin 93 Easy Particle Propagation — Jonas Lippuner 94 Editor’s Note — Idris Elbakri

Cover Image

Hyperpolarized helium-3 magnetic resonance imaging (MRI) methods are being developed in a handful of respiratory and MR centres to provide a quantitative method for the measurement of lung function and tissue microstructure by exploiting the diffusion properties of 3He. Feature article on page 77 presents longitudinal results in a small group of patients with clinically diagnosed RILI.. The figure illustrates 3He MRI images registered with 1H images and CT.

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 71 The Canadian Medical Physics Newsletter, COMP BOARD CCPM BOARD which is a publication of the Canadian Organi- zation of Medical Physicists (COMP) and the President: President: Canadian College of Physicists in Medicine Peter McGhee, Ph.D., FCCPM David Wilkins, Ph.D., FCCPM (CCPM) is published four times per year on 1 Thunder Bay Regional HS Centre The Ottawa Hospital Jan., 1 April, 1 July, and 1 Oct. The deadline for Thunder Bay, ON Box 927, 501 Smyth Road submissions is one month before the publica- Tel: (807) 684-7325 Ottawa, ON, K1H 8L6 tion date. Enquiries, story ideas, images, and [email protected] Tel: (613) 737-7700 x70010 article submissions can be made to: FAX: (613) 247-3507 Past President: [email protected] Idris A. Elbakri, Ph.D., MCCPM Jason Schella, M.Sc., FCCPM CancerCare Manitoba Nova Scotia Cancer Centre Vice-President: 675 McDermot Ave Halifax, NS Matthew G. Schmid, M.Sc., FCCPM Winnipeg, MB, R3E0V9 Tel: (902) 473-6011 BC Cancer Agency — Southern Interior Email: [email protected] [email protected] Phone: (204) 787-2856 399 Royal Avenue Kelowna, BC V1Y 5L3 Fax: (204) 775-1684 President Elect: Tel: (250) 712-3917 Members of the Editorial Board include: FAX: (250) 712-3911 To be announced at the COMP Tony Popescu Boyd McCurdy [email protected] Michelle Cottreau Parminder Basran 2010 AGM

Registrar: Please submit stories MS Word or ASCII text Secretary: Darcy Mason, M.Sc., FCCPM format. Images in Tiff format at 300 dpi resolu- To be announced at the COMP Medical Physics Dept. tion are preferred. Durham Regional Cancer Centre 2010 AGM 1 Hospital Court All contents of the Newsletter are copyright of Oshawa, ON L1G 2B9 Canadian Organization of Medical Physicists Treasurer: Tel. (905) 576-8711 ext 2816 and the Canadian College of Physicists in Medi- Fax: (905) 721-6102 William Ziegler, Ph.D. cine. Please do not reproduce without permis- [email protected] Allan Blair Cancer Centre sion.

Regina, SK Tel: (306) 766-2329 Chief Examiner: ADVERTISING (both corporate and job) [email protected] Robert Corns, Ph.D., FCCPM enquiries can be made to: BC Cancer Agency, Fraser Valley Centre COMP/CCPM Office Councillor for Communications: Medical Physics P.O. Box 72024 13750-96 Avenue Kanata North RPO Tony Popescu, Ph.D., MCCPM Surrey, BC, V3V 1Z2 Ottawa, ON, K2K 2P4 BC Cancer Agency — Vancouver Tel: (604) 930-4055 x654558 Canada Vancouver, BC Fax: (604) 930-4042 Telephone:(613) 599-3491 Tel: (604) 877-6000 ext. 2046 [email protected] Facsimile: (613) 599-1949 [email protected] E-mail: [email protected] Councillor for Professional Deputy Chief Examiner: Website: www.medphys.ca Boyd McCurdy, Ph.D., FCCPM Affairs: Div. of Medical Physics Joseph E. Hayward, Ph.D., MCCPM CancerCare Manitoba Juravinski Cancer Centre, 675 McDermot Avenue Hamilton, ON Winnipeg, MB R3E 0V9 Tel: (905) 387-9711 Ext: 67040 Tel: (204) 787-1966 Corporate Advertising [email protected] Fax: (204) 775-1684 [email protected] 1/2 page 1 Addn. page pages Councillor for Radiation Safety Secretary-Treasurer: & Technical Standards Advisory Member Sherry Connors., M.Sc., FCCPM Announcement $120 $120 Jean-Pierre Bissonnette PhD, MCCPM Dept. Medical Physics Princess Margaret Hospital Cross Cancer Institute Corporate Toronto, ON 11560 University Ave Member $180 $240 $120 Tel: 416.946.4501 ext: 2151 Edmonton, AB, T6G 1Z2 Non Profit [email protected] Tel: (780) 432-8775 Organisation $270 $360 $150 Fax: (780) 432-8615 Councillor for Science & [email protected] Corporate Non- Member $360 $480 $240 Education General Board Members: Marco Carlone PhD, MCCPM Color Add $480 (when available) Princess Margaret Hospital To be determined at the CCPM Toronto, ON 2010 AGM Tel: 416.946.4501 ext: 2409 Job Advertising Options [email protected] COMP/CCPM Office OPTION 1 ($240): Job posting on COMP/ CCPM website only (updated monthly) P.O. Box 72024 Kanata North RPO Ottawa, ON, K2K 2P4 OPTION 2 ($360): Job posting on COMP/ Canada CCPM website AND in InterACTIONS Telephone:(613) 599-3491 (single page) Facsimile: (613) 599-1949 OPTION 3 ($400): Job posting is immediately e E-mail: [email protected] -mailed to COMP/CCPM members (no website Website: www.medphys.ca or InterACTIONS posting) 72 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale Message from the COMP President

Welcome to this, my inaugural message professional organization. as COMP President. As I write I am dis- Now to the point: COMP cannot exist or covering my very first challenge: the function without the active participation most significant annual event in the of its Members. While the Executive COMP calendar, the Annual Scientific Director certainly facilitates and enables, Meeting (ASM), will commence in a the Members are the content specialists week or two and this article will not be and must be engaged. Moreover, Medi- published until a week or two following. cal Physicists constitute a particularly While I have thoughts of encouraging small community. As a consequence, you to attend the Annual General Meet- relative to sister organizations, a dispro- ing, to diligently review the background portionate effort is needed from all material to motions that will be brought Members in order to optimally engage forward, and to be prepared to bring for- the professional challenges that we face. ward your own ideas (which I do hope is We need to engender a culture where indeed what has transpired), such being a Member of COMP is more than thoughts can only be considered very paying fees and participating in the occa- early encouragement for 2011. Malcolm sional ASM. Far too often Board ap- McEwen and the Ottawa Local Arrange- pointments are essentially made by ac- ments Committee (LAC) look to have clamation. We have quite detailed by- put together an outstanding program and, laws regarding how to conduct an elec- while I look forward to an exciting and tion, and I cannot recall the last time they Dr. Peter McGhee stimulating meeting, I hope that those of were actually exercised. Would the or- you who have attended found it to be so. ganization not benefit from hearing two COMP President As my first opportunity to open what I or more individuals speak as to why they hope will be an ongoing dialogue, one would like a particular position, to offer able for continuing education. Please initial theme that I do want to take a mo- different visions of the direction in which weigh into this consideration if you have ment to highlight, and one that is cer- they would like to see COMP evolve? an opinion. By now Joe Hayward and the tainly not new, is that the Membership is Case in point, I wonder how many of Professional Affairs Committee should the lifeblood of COMP: COMP only you have any idea why I would want to be reporting glowingly about how you functions because of the voluntary ef- be the incoming President. (It’s ok ALL completed the Professional Survey, forts invested by its Members. I have though, looks like you will have no and they would also like to continue to been involved with COMP for much choice but to find out.) I am not at all encourage those with interest to get in- longer than I am willing to admit, my sure what the prospects are but, by the volved with the Bone Mineral Densi- first role with the Executive (now Board) end of my term, I do hope that COMP tometry accreditation process being being appointment as Councillor for Pro- has grown sufficiently that Members are sponsored by the Canadian Association fessional Affairs in 2003. As a result, I willing to not only stand but also to chal- of Radiologists. And Bill Zeigler, our have been witness to a number of pro- lenge for Board positions. So, how do we prudent and conscientious Treasurer, found changes in how COMP operates get there? I would very much like to hear asked me to relay a reassurance that that have significantly enhanced the abil- from you. And I do hope that this is at COMP is indeed financially sound. (For ity of the organization to serve its Mem- least a bit provocative…listening to my first message, I thought that this was bers. One of the most strategically pru- crickets chirping is for the most part a particularly positive point to include.) dent and effective moves was the crea- pleasant, but tends to not be terribly pro- He will, of course, be providing a full tion of the position of Executive Direc- ductive. report once the budget is approved. I tor. We have been extremely fortunate to With that out of the way, much of the would also like to echo Jason Schella’s have Nancy Barrett in this role as she has business of COMP will be addressed at appreciation for the efforts of Stephen truly been an invaluable asset in advanc- the ASM so, aside from a few highlights, Pistorius, Past President, and Patrick ing the ability of COMP to fulfill its six a more detailed update will be deferred Rapley, Secretary, both of whom will principal objectives. The Executive Di- to the next issue of InterACTIONS. Hav- have stepped down from the Board. And rector and her supports have become the ing had such a success with the first as for Jason himself, while I am certainly backbone of the organization, providing Winter School, Marco Carlone and the appreciative of his efforts and contribu- dedicated time and continuity that did Science and Education Committee (SEC) tions as well, I would mostly like to re- not previously exist. The fact that Nancy are stridently working towards achieving mind everyone that he is not off the hook became so indispensible so rapidly the same in 2011. If not already being yet as he is now Past President. I look makes me appreciate even more the ac- disseminated, details can be anticipated forward to working with him and rest of complishments and the dedication of to be forthcoming in short order. Marco the dedicated, motivated, and exception- those who contributed their time and is also approaching the Board to deter- ally capable individuals that comprise efforts to first establish and then, prior to mine whether the format of the ASM can your Board. More will be said on the her arrival, nurture COMP into a robust be modified to increase the time avail- (Continued on page 75)

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 73 Message from the CCPM President

The Canadian College of Physicists in Medicine has completed its membership certification process for 2010. Thirty The second objective refers to the Fel- new members are welcomed this year, lowship examination process. The third which represents a 10% increase in the objective is quite broad -- the only spe- membership of the College. cific mechanism by which CCPM pro- motes knowledge and disseminates in- The overall pass rate was 79% this year, formation in our field is through the which is comparable to past years. One CCPM symposium at the COMP Annual new member in the MRI subspecialty, Scientific Meeting. Apart from that, this and one in the Diagnostic Radiologic objective is accomplished through the Physics subspecialty, joins the College certification process itself, and by sup- this year. Three candidates wrote the port of COMP initiatives such as Inter- exam and did the oral exam in French ACTIONS, the ASM, and the Winter this year. The written question bank is School. still available in English only (we are working on addressing this), but candi- The first objective is the important one, dates can provide their written answers and it is worth noting how it is stated: in French. The objective of the College is to protect Dr. David Wilkins the public by identifying competent per- Chief Examiner Robert Corns was re- sons in our field. The College does not However, certification of individuals is sponsible for coordinating the entire exist to serve its membership, but to pro- only one component in protecting the exam process, and he deserves a large tect the public. Initiatives to serve the public and ensuring that those practicing thank you for the enormous amount of interests of the medical physics commu- medical physics are competent. There is work involved. Many others helped set nity in Canada are the domain of COMP, increasing recognition in health care of the exam, mark it, conduct oral exams, which it does through such things as this the importance of accreditation of the and coordinate logistics. By my count, newsletter, job postings, meetings and education programs which prepare indi- 29 CCPM members and fellows were conferences, promotion of the profes- viduals who present themselves for certi- involved, representing almost ten percent sion, salary and manpower surveys, tech- fication. This is the basis of the recently of the College. nical standards, lobbying on behalf of adopted policy that anyone applying for the profession, etc. These activities are CCPM certification after 1 Jan 2016 It is a testament to the success of the not the included in the mission of the must have graduated from either a College and its certification process that College. graduate or residency program accred- we are able to get 10% of the member- ited by CAMPEP. ship to volunteer their time to help run Like any professional college, CCPM is the examination process. Of course, this engaged in four main activities by which It is a reasonable expectation, recently process is at the core of the mission of it protects the public: articulated by advocates of patients the College and is essential to the future Running an examination process to harmed in the US by the medical use of of our profession. identify individuals who are radiation and experts testifying before competent to practice clinical Congress, that medical physicists, like What is the mission of the CCPM? The medical physics; any health care providers, should be Bylaws state the Objectives as: Maintaining a publically accessible trained in accredited education programs registry of competent individu- for the tasks they are expected to per- The objective of the College shall be to als; form and should have their competency protect the public by: Running a maintenance of compe- certified by nationally respected institu- (1a) Identifying competent persons who tency process (recertification); tions. are responsible for applications of the Having a disciplinary mechanism by physical sciences in the medical field. which incompetent individuals Anyone interested in helping the Cana- (1b) Identifying individuals demonstrat- or those acting unethically can dian medical physics profession meet the ing excellence in the practice of medical have their certification revoked. challenges discussed above, should con- physics. The fact that so many are seeking CCPM sider getting involved in the work of (2) Promoting knowledge and dissemi- certification (10% growth in the College CCPM or COMP. To volunteer for nating information relating to develop- this year) is an indication that those prac- CCPM, contact the chair of the nomina- ments of the physical sciences in the ticing clinical medical physics recognize tions committee (Brenda Clark), myself, medical field. the importance of the first objective. or any Board member.

74 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale Message from the Executive Director of COMP/CCPM

.2010 ASM port to those working in the medical By the time you read this issue of Inter- physics profession as Physics Associates. ACTIONS, the 2010 ASM will be behind The group has met in both Victoria and us. It was truly a pleasure working with Ottawa and is also conducting its own Malcolm McEwen and the Ottawa LAC professional survey with the support of on this event. A special thank you to our the COMP office. corporate sponsors: Varian, Elekta, CNSC, Philips and Tomotherapy - your generous support makes a great deal of Connecting with Adjacent Communities difference to the quality of the meeting. As part of the Board meeting that took place in Ottawa before the 2010 ASM, Thank you to all participants for provid- representatives from CARO, CAR, ing feedback via our evaluation survey. CAMRT, CAP and CMBES were invited Your support helps us in the planning of to participate in a roundtable discussion. future meetings. On that note, the 2011 The purpose of the session was to facili- meeting will be a joint meeting with the tate information-sharing and networking AAPM in Vancouver. Mark your calen- between the various organizations. dars for July 31st to August 4th!

2010 Professional Survey As always, please feel free to contact me All full members of COMP were invited at [email protected] or Gisele Kite at to participate in the 2010 Professional [email protected] at any time with Ms. Nancy Barrett Survey. This survey is conducted every your feedback and suggestions. second year and is developed by the Pro- fessional Affairs committee(PAC) in an effort to provide you with the best and (Continued from page 73) Did You most up-to-date professional information topic of Board members in the next is- on Canadian medical physicist salaries sue. Know? and benefits. The results of the survey With that, so ends my first challenge. will be published in an upcoming issue of Although it would be nice, I doubt it will InterACTIONS. be the last. I hope that this column will not be a one way street and that the Board and I do hear from you. When an Winter School 2011 issue is important to you, please take the InterACTIONS Building on the success of the inaugural time to let us know, including any sug- is published four times school that took place in Banff in January gestions as to how we could make such 2010, plans are well underway for the communication easier. COMP is your a year 2011 Winter School which will be taking organization. in beautiful Mont Tremblant from Janu- Oh, and by the way, for those who may ary 30, 2011 to February 3, 2011. Don’t have forgotten, the six principal objec- January , April, July, miss this opportunity for continuing edu- tives are: cation and networking. October · To promote scientific knowledge; · To further the exchange and publica- The COMP Student Council tion of scientific or technical informa- A Student Council was established at the tion; Next deadline for the 2008 meeting in Quebec City and has · To promote educational opportuni- grown both in numbers and enthusiasm. ties; October issue is A special section of the COMP website · To develop and protect professional has been established with information that September 1! standards; is pertinent to students and the group also connects via a Facebook group. Thank · To promote and encourage certifica- you to Alejandra Rangel and Nadia Oc- tion by the Canadian College of Physi- Get your material in tave for their leadership and energy for cists in Medicine; and this important initiative. To link to activities of other organiza- early! tions with similar objectives. Just let me know if you believe we are Physics Associates not making the grade. Through the PAC and particularly Joe Looking forward to having seen you in Hayward, COMP has been providing sup- Ottawa. Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 75 CNSC Feedback Forum Submission of Annual Compliance Reports Kavita Murthy, Director Class II Nuclear Facilities and Equipment Division Canadian Nuclear Safety Commission

The CNSC recently launched a project CNSC using the web interface. It will plan will make ACR-online available called ACR-Online which will allow allow you to upload complex invento- to different licence types gradually so licensees to complete and submit their ries, and when submitted, provide in- everyone will be able to ease into the Annual Compliance Reports (ACRs) stant confirmation that the ACR has new way of doing business. The first using a web interface. This interface been received. You will be able to roll-out is expected to take place in will be similar to the one that the view the status of previously submit- January 2011, with the licensees who CNSC has had in place for the pur- ted ACRS, and view and download have medical linear accelerators. The poses of Sealed Source Tracking. It is read-only copies of submitted ACRs. CNSC will contact you when the sys- expected that this online submission Based on information that is available tem is ready for launch, but in the capability will make the process of to the CNSC on your licensed activi- meantime, you can look for informa- ACR submission faster and much sim- ties, the system will also make data tion on our website: pler for licensees. entry into the various mandatory fields www.nuclearsafety.gc.ca much simpler and more accurate by Annual compliance report is submitted providing drop-down lists of equip- Class II regulations now require for each licence every year (!) by the ment and source details, location de- RSO certification licence holder and contains informa- tails, etc. It is expected that later ver- On the recommendation from Treasury tion about the licensed activities nec- sions of the project will have much of Board Ministers, the Governor Gen- essary to reassure the CNSC that the the information pre-filled. Addition- eral brought into force the Regulations activities conducted under that licence ally, we plan to automate the process Amending the Class II Nuclear Facili- were in compliance with the regula- of receipt and notification of when an ties and Prescribed Equipment Regula- tions and the licence conditions. A ACR is submitted, and automatically tions. desktop review of the ACR is one of generate flags when information pro- three tools that the CNSC uses to en- vided in the ACR does not match our The regulations come into effect sure a licensee’s ongoing compliance records, thus making the process of on May 13, 2010, the day they were with regulatory requirements. The assessment more efficient. It will al- registered, and were published in the other two methods are Type I and low us to collect a more complete in- Canada Gazette, Part II on May 26, Type II inspections, both of which ventory of sealed sources, and make it 2010. involve a site visit by CNSC staff. possible to trend and track the infor-

mation we collect much more effec- For English go to: In addition to administrative informa- tively. tion, there are some key performance http://www.gazette.gc.ca/rp-pr/ related questions in all ACRs such as In order to ensure secure data collec- p2/2010/2010-05-26/html/sor-dors107 sealed source inventory management, tion, you will be required to obtain -eng.html facility workload, dose summaries for authorization codes from the CNSC to Or, http://laws.justice.gc.ca/PDF/ monitored staff, etc. Information gath- allow you access your ACR online. Regulation/s/sor-2000-205.pdf ered via ACRs is used by CNSC staff The user authentication process will when preparing for inspections, trend- ensure that the correct information is Pour la version française, visitez : ing licensee performance against pre- released to the right person so neither vious years as well as against other your identity nor your information is http://www.gazette.gc.ca/rp-pr/ similar licensees. compromised. The system we are p2/2010/2010-05-26/html/sor-dors107 building will meet the Government of -fra.html If you hold a CNSC licence, you will Canada’s strict guidelines about gath- Ou, have submitted an ACR to the CNSC ering and storing this type of informa- http://laws.justice.gc.ca/PDF/ every year. ACR-Online will allow tion. Reglement/S/SOR-2000-205.pdf you, the licensee, to access your ACR using a secure web interface to fill it The ACR-online project is expected to If you have any questions about this out online, or download it to your local be rolled out in several phases, each article or any other published in this computer and then complete it at your phase incorporating features that allow series, contact me at leisure. In both cases, once it is com- for increasing automation for both the [email protected] plete you can then submit it to the submitter and the CNSC. The roll-out 76 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale Study Visits Feature Article Pulmonary function testing was performed prior to imaging and included spirometry and plethysmography. Scanning was per- Detection of Lung Remodelling formed at 3.0T using an Excite 12.0 MRI system (GEHC, Milwau- kee, WI). Hyperpolarized 3He with 30% polarization was provided following Radiation Therapy us- through a spin exchange optical pumping system (Helispin, GEHC, 3 Durham, NC) at a dosage of 5 mL/kg and mixed with medical N2 ing Hyperpolarized He Mag- to 1.0L. Three sets of images were acquired during a 15 second breathhold; a spin density image, a proton image and a diffusion netic Resonance Imaging weighted image. Image and Statistical Analysis 1,2 2-4 1 L. Mathew* , S. Gaede , A. Wheatley , R. 3He and 1H images were manually segmented on a slice-by-slice Etemad-Rezai5, G. Rodrigues,3,4 and G. basis to acquire a ventilation volume (VV) and thoracic cavity vol- 1,2,3,5 ume (TCV). Percent ventilated volume (PVV) was calculated as a Parraga ratio of the ventilated volume (3He) to thoracic volume (1H). All (1) Imaging Research Laboratories, Robarts Research Insti- volumes were calculated for the ipsilateral lung (radiation target tute, London, ON, (2) Department of Medical Biophysics, Lon- determined by cancer location), the contralateral lung, and total lung. Apparent diffusion coefficients were calculated from diffu- don, ON, (3) Department of Oncology, The University of 2 Western Ontario, London, ON, (4) Radiation Oncology Pro- sion weighted images using b=1.6s/cm for each lung independ- gram, London Regional Cancer Program, London, ON, (5) ently and combined. The paired t-test was used to assess differ- Department of Medical Imaging, The University of Western ences between the ipsilateral and contralateral lungs, as well base- Ontario, London, ON line and follow up parameters. Image Registration Feasibility of single point image registration of 3He-1H, 3He-CT Editor’s note: This article is the recipient of the 3rd place in and 3He-radiation planning images was assessed, and resultant reg- the J.R. Cunningham Young Investigators Award 2009. istered images were evaluated using a modified overlap coefficient

AMRI I ACT INTRODUCTION W =100 x AMRI The lung is an extremely radiosensitive organ highly susceptible to radiation induced injury. Despite the fact that radiation treatment The mean ADC and ADC standard deviation were calculated for dose to thoracic tumours is limited in order to decrease the inci- the 5 center slices. The mean ventilated, thoracic and percent ven- dence of this injury, radiation induced lung injury (RILI) still oc- tilated volume and standard deviation were calculated from re- curs in as many as 34% of thoracic cancer cases involving radiation peated measures for the ipsilateral lung, contralateral lung and treatment. Symptoms of RILI are a result of structural changes in combined lung volume. The difference between baseline and fol- the lung including capillary obstruction and septal thickening in the low up MRI measurements were calculated for the four subjects pneumonitis phase of the injury, and further septal thickening with returning for a second visit, and a mean difference is reported. 3 obliteration of the alveolar space in the fibrotic phase, all of which Differences between ipsilateral and contralateral lung He MRI result in the functional impairment of the lung. Functional impair- measurements were assessed using a paired t-test. The paired t-test ment can be observed using spirometry, which shows an immediate was also used to evaluate differences between parameters measured and rapid functional decline, with a steady decline continuing after at both baseline and follow up. Correlations between imaging, two year. Although pulmonary function measures are good indica- radiation treatment and pulmonary function parameters were as- tors of global lung response, the regional functional impact of sessed using Pearson’s product moment correlation coefficient. inflammation and fibrosis in the lung over time remain relatively unclear. RESULTS Hyperpolarized helium-3 magnetic resonance imaging (MRI) Seven subjects were enrolled following a diagnosis of RILI based methods are being developed in a handful of respiratory and MR on symptomatic presentation, six following radiation treatment for centers to provide a quantitative method for the measurement of lung cancer and one following breast cancer treatment. The mean lung function and tissue microstructure by exploiting the diffusion period of time between the start of radiation and the first visit was properties of 3He. Although 3He MRI has been applied as a re- 35.1 ± 12.2 weeks, with the first visit being 9.1 ± 5.1 weeks follow- search tool in a number of respiratory diseases and explored as a ing the initial report of RILI symptoms. Four subjects returned for potential radiation treatment planning tool, it has not to our knowl- a follow up visit 22.0 ± 0.8 weeks later. The remaining three sub- edge been developed to monitor RILI progression. Here we pre- jects were deceased or otherwise unable to return for follow up. sent longitudinal results in a small group of patients with clinically Subjects were treated with a mean dose of 58 ± 7 Gy, and the six diagnosed RILI. subjects treated for lung cancer received a V20Gy 32% ± 3%. Representative center slice functional images and corresponding MATERIALS AND METHODS ADC maps are shown for subjects with RILI following radiation treatment for a right hilar mass (Figure 1a), a left upper lobe mass Study Subjects 3 Subjects (n=7) were recruited from the London Regional Cancer (Figure 1b) and a left hilar mass (Figure 1c). All mean He MRI Program based on a clinical diagnosis of RILI, and four subjects ADC and ventilation measurements are reported in table 1 for the returned for a follow up visit 22.0 ± 0.8 weeks later. All subjects ipsilateral lung, contralateral lung and total for both baseline and provided written informed consent to the study protocol approved follow up visits. For the baseline scan a difference in the mean 2 by The University of Western Ontario Health Research Ethics ADC of 0.03 cm /s between lungs was observed, although this Board and Health Canada failed to show significance (p=0.053). Ventilation images showed

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 77 Image registration results are provided in Figure 3 for a representative subject, with (a) showing the 3He MRI image, (b) image registration of 3He MR and 1H images where 3He signal is shown scaled from red and the 1H image is provided in grayscale. For the same representative subject who underwent intensity modulated radiation therapy (IMRT) registration with CT, and radiation structural plans are shown in the axial and coronal planes in Figures 3 c, d, e and f respectively. 1H – 3He registration was assessed for the baseline visit in all seven subjects, and a mean overlap coefficient of 93.6 ± 4.6% was reported. 3He MR – CT registration was assessed for four subjects, with a mean overlap coefficient of 75.3 ± 10.5%.

DISCUSSION In this first longitudinal application of 3 Figure 1. Representative Baseline and Follow up Ventilation Images, ADC Maps and hyperpolarized He MRI in subjects ADC Histograms after presenting with RILI we observed A, B and C show representative subjects at baseline (i and ii) and follow up (iii and iv). i and a significant difference in the baseline iii show ventilation images at baseline and follow up respectively, while ii and iv show an thoracic cavity volume of the ipsilateral ADC Map and Histogram for the same subjects at baseline and follow up respectively and contralateral lungs indicitave of thoracic remodelling following radiation injury. Importantly, we noted a signifi- a significant difference in ventilated volumes between ipsilateral cant difference in the percentage of the thorax ventilated, as meas- and contralateral lungs (p=0.014), as did thoracic cavity volumes ured by PVV, which was higher in the contralateral lung, suggest- (p=0.027). Percent ventilated volumes were significantly different ing that the functional capacity of the contralateral lung remains (p=0.025), and 33% lower in the ipsilateral lung as compared to the high following structural remodelling of the lungs. The lower PVV contralateral lung. reported in the ipsilateral lung can likely be attributed to inflamma- At follow up total mean ADC values were significantly higher than tion and scarring due to the targeted radiation dose or the presence baseline (p=0.016). When measured independently ipsilateral of cancer (either original tumour or re-growth), causing the narrow- mean ADC was not significantly different between baseline and ing or closure of the airways. The finding of a high percent venti- follow up (p=0.053), while contralateral mean ADC at follow up lated volume in the contralateral lung of all subjects shows that was significantly higher as compared to baseline (p=0.003). The despite receiving radiation dose, the contralateral lung remains contralateral lung also showed a significant increase in percent highly functional; not otherwise evident through pulmonary func- ventilated volume at follow up (p=0.012), while no other ventilation testing or radiography. tion parameters showed a statistically significant change. For the small number of patients who were scanned at follow up, 3 Baseline ipsilateral mean ADC and the radiation parameter V20Gy there was a significant change in both He ADC (contralateral and were significantly correlated (R= -0.961, p=0.009), while the con- combined) and PVV between baseline and follow up visits which tralateral ventilated volume at baseline was significantly correlated suggests that 3He MRI can sensitively detect lung structural and with the mean lung dose (R=0.94, p=0.016). The only baseline functional changes as RILI progresses. In this small number of pulmonary function value showing a correlation with imaging subjects there was a significant increase in ADC (which typically measurements was DLco, which correlated with the ipsilateral venti- reflects a worsening of airspace disease or emphysema) observed lated volume (R=0.83, 0.041). Total dose was also correlated with over a period of 20 weeks was greater than the rate previously es- the follow up ipsilateral ventilated volume and percent ventilated tablished as due to either aging or due to COPD progression. volume (R= -0.98, p=0.024 and R= -0.98, p=0.015 respectively). Based on the timeline of our imaging the reported increase in ADC

Table 1. Baseline and Follow up 3He MRI ADC and Ventilation Measurements

Baseline 5 month Follow up Ipsilateral Contralateral Total Ipsilateral Contralateral Total WL ADC (SD) cm2/s* 0.33 (0.06) 0.30 (0.06) 0.31 (0.05) 0.35 (0.04) 0.32 (0.04) 0.32 (0.04) WL ADC SD (SD) cm2/ 0.12 (0.07) 0.11 (0.07) 0.11 (0.08) 0.24 (0.02) 0.19 (0.05) 0.20 (0.04) s* WL VV (SD) L 0.9 (0.5) 2.1 (0.6) 3.0 (0.7) 1.0 (0.7) 2.5 (0.7) 3.5 (0.6) WL TCV (SD) L 1.6 (0.3) 2.3 (0.7) 3.9 (0.8) 1.4 (0.2) 2.4 (0.7) 3.8 (0.5) WL PVV (SD) % 55 (29) 88 (5) 76 (12) 68 (45) 103 (5) 92 (15)

78 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale in the contralateral lung reflect a decrease or resolution in radiation induced inflammation over time following radiation, while no change in the ipsilateral ADC was reported due to the likely occurrence of irreversible fibrosis. In addition, at follow up, while the volume of the thoracic cavity showed no significant change, PVV increased possibly due to a similar decrease in inflammation in the airways of the contralateral lung. The increase in PVV of the contralateral lung over this short period of time perhaps also suggests that functional remodelling occurs in response to loss of function, fibrosis and volume loss observed in the ipsilateral lung as evidenced in the low ipsilateral Figure 3. 1H – 3He and 3He – CT Image Registration PVV observed in the majority of subjects. A) 3He MR image B) 1H – 3He MR image registration C) coronal 3He – CT image registration D) axial 3He – CT image registration E) coronal 3He – CT with structural con- We showed that 3He MR registration was tours image registration F) axial 3He – CT with structural contours image registration feasible with both 1H MRI, CT and radiation dosimetry treatment plans. Despite the fact that for some subjects with RILI there was significant thoracic CONCLUSIONS remodelling; 1H / 3He registration was implemented successfully In this small pilot study of seven patients with RILI, we show the likely due to the fact that the elapsed time between scans was on potential for 3He MRI to provide structural and functional infor- the order of minutes, and the subject was not moved between mation about target and non-target lung regions. Furthermore, we scans. Furthermore, registration of 3He ventilation images with observed that radiation induced functional effects were largely CT and radiation dosimetry plans were also found to be feasible. restricted to the ipsilateral lung and remained constant, while lung The feasibility of this registration will be important for future function as measured using 3He PVV increased in the contralateral studies aiming to assess functional information that 3He MR yields lung over time. in conjunction with structural data from CT.

C D

Figure 2. Plot of Longitudinal Differences in 3He MRI derived measurements Differences between baseline and follow up data for subjects returning for a second visit (n=4) are observed for A) FEV1 %pred, B) contralateral ADC, C) ipsilateral PVV and D) contralateral PVV.

were written by the author to put to- calculate the Coeff6 – A Tool for gether much of the tabular material that required, and Radiation Physics appears in the Appendix of “The Phys- missing, stop- ics of Radiology”. At the time of writ- ping power Jack Cunningham, Ph.D. ing that book, stopping powers for elec- data. The Be- trons for some of the materials that the- Bloch Coeff6 is a program, written in Visual were used for constructing dosimeters equation for Basic 6.0, for the purpose of creating and phantoms were not readily avail- energy loss by and manipulating tables of electron able. Such materials were particularly electrons was stopping powers and photon interaction relevant for measuring dose from the solved along coefficients for elements and composite spectra of photon beams produced by with the Sternheimer calculation for the materials. The origin of this project was the, then new, generation of linear ac- effect of the density of the material. a series of FORTRAN programs that celerators. There was thus a felt need to (Continued on page 80)

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 79 (Continued from page 79) Book Review: Clinical Dosimetry Meas- urements in Radiotherapy By D.W.O. Rogers, Photon interaction data had kindly been made available, via magnetic tape, Joanna E. Cygler, Editors, Proceedings of the AAPM Sum- from what is now NIST. We thus had a mer School 2009 useful collection of basic data. The next Alasdair Syme, PhD step in the project was the creation of programs that would calculate ratios of Cross Cancer Institute, Edmonton AB averaged stopping powers for various combinations of materials and spectra This hardcover publication is the mono- tational details behind TG-51 as reason- representing a wide range of commonly graph of the 2009 AAPM summer school. able”. This collection of chapters used radiotherapy machines. In a simi- It is a lengthy volume (over 1100 pages) (including the underlying cavity theory) is lar way, programs were written to cal- that covers a wide range of topics under extremely informative and well written. culate ratios of mass energy absorption the general umbrella of clinical do- It goes into significantly more detail than coefficients for these materials and simetry. It is presented in 32 chapters and a number of standard textbooks. The spectra. 2 appendices. The print is high quality medical physics community will benefit and easy to read, however the figures in greatly from the effort put into compiling With the availability of programming the document range in quality from excel- this information. tools such as Visual Basic, the author lent to quite poor (usually due to the fact realized that it would be practical to that they are reproductions from earlier The chapters on radiation detectors also rework these old Fortran programs and publications). Each chapter contains an provide a wealth of information on the to bring them together to produce a tool extensive reference list and a series of principles of operation, applications and that might find useful application in the problems for which answers are provided limitations of each detector, as well as practice of radiation physics and in the in one of the appendices. The text and correction factors the user must be aware teaching of that subject. This program, figures are conveniently available elec- of. The volume of information presented called Coeff6, is the result. It is so tronically on the accompanying CD and can appear daunting, however the text is the lectures from the summer school are well segmented which allows the reader named because the component modules also available on the AAPM’s website. to locate appropriate subsections with are written in Visual Basic 6.0. ease. The work begins with a historical over- Program Coeff6 is acompanied by an view of dosimetric measurements and A few chapters make for challenging extensive library of electron stopping calibrations and is followed by two chap- reading either because they do not stray power and photon interaction coeffi- ters covering basic physical interactions far from previously-published material cient data, and information concerning of radiation, quantities relevant to do- (i.e. kilovoltage dosimetry) or because the composition of a number of com- simetry and cavity theory. Subsequent they provide a level of detail that is likely posite materials that are useful in radia- chapters build on this foundation to de- to interest mainly those with an active tion physics. It also includes routines scribe the physics of TG-51 and its clini- research interest in the field (i.e. reference for creating new tables of these data. cal implementation. Three chapters are -quality brachytherapy dosimetry). None- There is also a collection of both pho- devoted to brachytherapy dosimetry theless, the book benefits from the inclu- ton and electron spectra and of routines (calculations and measurements). Eleven sion of these chapters. for creating and manipulating them. chapters cover a wide range of radiation The spectra can be used to calculate detection instrumentation (ionization This book will serve as an excellent refer- various quantities averaged over the chambers, radiochromic and radiographic ence for any practicing radiation oncol- film, TLDs and OSLs, diamond detectors, ogy medical physicist. The variety of spectra and are useful for demonstra- diodes, MOSFETs, gel and chemical do- topics covered and the quality of writing tions. Coeff6 includes procedures and simeters and plastic scintillators). The make it a valuable resource. The level of other demonstrations that may be gen- remaining chapters cover an array of top- detail offered in many areas, and particu- erally useful in the teaching, learning or ics including kilovoltage x-ray dosimetry, larly in the TG-51 physics sections, likely practice of radiation physics. electron dosimetry, primary standards of exceeds that found in most didactic measurement, instrument calibration, graduate courses. As such, medical phys- The modern source of the data in the quality assurance in clinical dosimetry, ics residents in this field who take the Coeff6 library are websites hosted by IMRT dosimetry, small field dosimetry, time to digest this work will benefit from NIST. hadron dosimetry and uncertainties in a very strong theoretical foundation in the dosimetric measurements. area of clinical dosimetry. These indi- Coeff6, in executable form, along with viduals will certainly also value this text the library of data files and a detailed One of the highlights of the work is the as they prepare for their certification ex- manual, which includes the relevant description of the physics of TG-51 and ams! In summary, this book deserves the physics, may be freely obtained on CD its clinical implementation. As Dave status of “must have” within the field of from the author. Instructions and the Rogers states, this “is a long-overdue ef- radiation oncology medical physics. source code are included. fort to document and explain, in a single place, as much of the physics and compu-

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82 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale

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84 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale Report of the 2009 Harold E. Johns Travel Award Visit Hyperpolarized Gas Magnetic Resonance Lung Imaging at the Robarts Research Institute in London, Ontario Dr. Atiyah Yahya Cross Cancer Institute, Edmonton, Alberta

I was supported by the Harold E. Johns travel award to visit the respiratory imaging group at the Robarts Research Insti- tute in London, Ontario, for a week during March 2010. I was kindly hosted by Dr. Giles Santyr who arranged for me to observe some hyperpolarized gas lung MRI (magnetic resonance imaging) experiments. In addition, he organized meetings for me with other academic staff, post-doctoral fellows, and graduate students. I also had the opportunity to present a seminar on some of my research to the laboratory. The following article provides details of my visit and the valu- Figure 1: Volunteer being scanned for a 3 able information that I learnt from it. hyperpolarized He study on the 3 T. The RF coil around the volunteer transmits Dr. Giles Santyr (right) and Dr. Atiyah 3 MRI research scanners at the Robarts and receives at the He Larmor frequency Research Institute: (97.3 MHz at 3 T). low density of the gases. After the gas is hyperpolarized it is collected and the pa- The Robarts Research Institute hosts an of lungs as well as the numerous air- tient inhales it while in the scanner. An impressive number of MRI research scan- tissue interfaces, which result in large MRI image of the gas is obtained while ners. Hyperpolarized gas MRI experi- susceptibility gradients causing the MRI the patient undergoes a breath hold. Sig- ments are conducted with two scanners, a signal to rapidly decay. During the last nal is only visible in lung regions which 3 T whole-body scanner (Figure 1), and a decade, advancements in lung MRI have contain the gas. Dark areas indicate poor home-built 0.075 T low-field small ani- been made by exploiting hyperpolarized ventilation implying an abnormality. 3 129 3 mal scanner (Figure 2). The centre also He or Xe gas as a contrast agent and Hyperpolarized He gas lung MRI has 3 129 has a home-built animal insert equipped detecting signal from the He or Xe been used to study a number of respira- with gradient coils that can provide gradi- nuclei. Hyperpolarization of the gases is tory diseases at the Robarts Research In- ent strengths up to 500 mT/m (Figure 3). done by spin exchange optical pumping, stitute including asthma, cystic fibrosis, The animal insert was designed such that and it enhances the signal producing mag- and chronic obstructive pulmonary dis- 3 it can easily be slid into the bore of the 3 netization by approximately five orders of ease (COPD). Figure 5 shows He lung T magnet. In this manner, the 3 T ma- magnitude, thereby compensating for the MRI images obtained from the studies. chine can be used for human studies or Regions of poor ventilation are clearly for high resolution animal experiments. observable. Hyperpolarized gas MRI In addition to the mentioned scanners there are three more MRI systems at the Robarts Institute at the Centre for Func- tional and Metabolic Mapping (CFMM), namely, a whole body 3 T scanner, a 7 T brain imaging scanner, and a 9.4 T animal system. I had the pleasure of being toured around the CFMM by Dr. Ravi Menon who also spoke to me about the challenges associated with high-field MRI.

Hyperpolarized gas lung MRI at the Robarts Research Institute: Figure 2: Low field 0.075 T animal scanner designed and constructed at Robarts Introduction: for hyperpolarized gas MRI of rodent 1 Conventional proton ( H) MRI of lungs is lungs. Figure 3: Animal gradient insert designed challenging due to the low proton density to slide into the 3 T scanner. Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 85 exchange with optically pumped Rb va- This mixture was placed in a 1 L bag, pour. Approximately one litre of 3He is previously vacuumed to minimize the placed in a glass cell which contains presence of O2, which if present would 3 small amounts of pure Rb and N2 (N2 cause rapid depolarization of the He, and allows for more efficient optical pump- was quickly taken to the patient. A mem- ing). The cell is in a magnetic field of ber of staff instructed the patient how to approximately 15 G and is at a pressure of inhale the gas and once it was all con- a few atmospheres. It is heated to about sumed the patient held his breath, a signal 150 °C, causing the Rb to vaporize. A was given to the MRI technologist, and circularly polarized laser light, tuned to the 3He scan was acquired in a few sec- the desired electron resonance of Rb (795 onds using a 2D fast gradient echo se- nm), is applied to the cell, and the result quence. It is essential that the image be is a high electronic polarization for the Rb acquired rapidly because once in the gas. Polarization is transferred to the 3He lungs the 3He loses most of its polariza- nuclei through collisional exchange. The tion in about 20 s. optical pumping is conducted for several hours (12 – 20 hours) after which the 3He Rat 3He MRI scan at 0.075 T: is 40 – 45 % polarized. The gas is cooled In addition to the human scan, I also had 3 Figure 4: Home-built He RF coil for rat to room temperature, which causes the Rb the chance to watch a rat imaging session imaging with the 0.075 T scanner. The to condense on the walls of the cell. The at the low-field scanner. Prior to the scan outer coil is for uniform RF transmission, 3He is dispensed and used immediately or the rat was anesthetized, and intubated. while the smaller, inner coil is for sensi- stored in a magnetic field until the patient An air-tight seal was ensured between the tive RF reception. is in the scanner and ready to be scanned. trachea and intubation so that the rat’s The patient was positioned supine on the breathing could be controlled by a venti- experiments of rat lungs are also being patient bed with a 3He RF coil placed lator. The rat was positioned supine carried out to investigate rat models of around his chest (as shown with the vol- within the 3He RF coil displayed in Fig- disease. unteer in Figure 1), and was entered feet ure 4 in the centre of the magnet. The first into the magnet. Some 1H images ventilator system delivered the hyperpo- Human 3He MRI scan at 3 T: were acquired by the MRI technologist larized 3He to the rat through mechanical I had the opportunity to observe the pro- for comparison with the 3He images. ventilation. cedure for a 3He MRI scan on an asth- During this time the hyperpolarized 3He matic patient volunteer. The first step was dispensed from the polarizer. The Hyperpolarized 129Xe lung studies: was to hyperpolarize the 3He. This was amount of 3He required was calculated as Unlike 3He, 129Xe can be absorbed into accomplished with a spin exchange opti- 5 mL per kg of the patient’s body weight. the blood or tissue after being inhaled. 3 cal pumping unit, shown in Figure 7, The He was added to N2 gas in a large This property renders it advantageous which hyperpolarizes the 3He by spin syringe to form a litre mixture of gas. despite its lower sensitivity. 129Xe can Figure 5: 3He lung MRI images acquired at 3 T

Asthma patient Cystic fibrosis patient COPD patient Healthy volunteer Wheatley et al. SPIE pro- Ahmed et al. RSNA 2009 Mathew et al. Acad Radiol. 2008 ceedings. 2007

Figure 6: a) 129Xe and b) 3He MRI images of normal rat lungs acquired with the low-field animal scanner. The lower signal to noise ratio (SNR) of the 129Xe image stems from the lower gyromagnetic ratio of 129Xe and the fact that the 129Xe may not have been hyperpolarized to the same degree as the 3He. Images are courtesy of William Dominguez Viqueira.

86 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale Figure 7: Spin exchange optical pumping 1 system. The labelled parts are: 2 1 1) Helmholtz coil pair that provides the magnetic field. 3 5 2) The optical cell. 3) Circularly polarized laser light source. 4) Gas outlet. 5) Monitor that displays amount of polarization.

4 13C nuclei. 13C polarizations of about 10 – 20% can be attained in approximately two hours. To transform the sample into an injectable solution without much loss of polarization it is dissolved and rapidly melted with a hot buffer.

Visit to the London Regional Cancer Program (LRCP): On one of the days Dr. Santyr arranged an also be hyperpolarized by optical pump- 129Xe by » 200 ppm. Both hyperpolarized afternoon visit for us to the London Re- ing; however, this is done in a continuous 3He and 129Xe magnetic resonance tech- gional Cancer Program, a hospital in Lon- flow fashion without storage in the optical niques require pulse sequences that en- don that provides treatment and support pumping cell. Instead, the hyperpolarized able efficient use of the enhanced spin services to cancer patients and their fami- 129Xe flows out of the cell and is collected lies as well as being a research and teach- 129 magnetization prior to its depolarization in liquid N2. The Xe freezes and its in addition to tailored RF coils tuned to ing hospital. At the LRCP we were given polarization is maintained by placing it in the appropriate Larmor frequencies. a tour by Dr. Kevin Jordan and Dr. Jerry a magnetic field. To convert it back to a Therefore, pulse sequence and RF coil Battista. We were introduced to the fasci- gas state, it is rapidly heated in boiling design form a significant component of nating research being done in the areas of water situated in a magnetic field in order the research at the respiratory MRI labo- photodynamic therapy and optical CT to sublimate the gas and collect in a bag ratory. measurements of three dimensional dose for delivery. Figure 8 displays the home- distributions in radiochromic gels. A 129 built Xe optical pumping system at the Hyperpolarized 13C NMR at the Ro- number of graduate students also pre- Robarts Research Institute. barts Research Institute: sented overviews of their valuable re- The Robarts Research Institute also hosts search in the field of adaptive radiother- Research projects: a 13C DNP (dynamic nuclear polarization) apy. From my meetings with the post-doctoral polarizer that hyperpolarizes 13C nuclei. fellows and the graduate students I re- It is being used to hyperpolarize 99%-13C Concluding remarks: ceived an overview of the variety of 1 My visit to the Robarts Research Institute 3 129 pyruvate for animal experiments. Within hyperpolarized He and Xe MRI re- a minute after pyruvate injection into the was enjoyable and benefited me greatly. search projects taking place at the Robarts subject signal can be collected from pyru- The opportunity to speak with researchers Research Institute. The projects include in the field and to watch experiments be- 3 vate and its metabolic products, namely, measuring He ventilation maps in lactate, alanine, and bicarbonate. The ing conducted provided me with valuable healthy elderly volunteers, asthma, technique is promising in the study of insight as to what is required to initiate COPD, cystic fibrosis, and lung cancer hyperpolarized gas lung MRI studies at 3 cancer where lactate levels are associated patients. He ventilation maps are also with tumour progression. While I was at my institute, where the methodology being used to study the effect of exercise the Robarts Institute I observed the DNP should have useful application in lung in asthma patients, and radiation induced process of 13C hyperpolarization which cancer studies and in lung radiotherapy pneumonitis in lung cancer patients. treatment planning. 3 differs somewhat from the optical pump- Moreover, He apparent diffusion coeffi- ing method used for 3He and 129Xe. 350 – cients (ADCs) are being employed to 400 mg of 13C enriched pyruvate is mixed Acknowledgments: investigate emphysema in COPD patients with 6 – 7 mg of trityl radical and a small First of all, I must thank the CCPM for as well as in emphysema rat models. In amount of Gd3+, which has been found to awarding me the 2009 Harold E. Johns addition to 3He experiments, the solubility travel award, which made my trip to the 129 increase the amount of polarization. The of Xe in blood is being exploited to solution is placed in a 3.35 T magnetic Robarts Research Institute possible. I am study gas exchange with blood, which can field and is frozen in liquid helium (about also indebted to Dr. Giles Santyr for host- become degraded in pulmonary diseases 1.4 K). The magnetic field and the low ing and organizing my visit while making and in radiation induced lung injury. The temperature significantly polarizes the me feel more than welcome. In addition, exchange can be determined by magnetic trityl free electrons. Subjecting the mix- I thank all the staff, post-doctoral fellows resonance spectroscopy techniques be- and students who spent time with me dis- ture to » 94 GHz microwave irradiation cause 129Xe in blood yields a peak that is cussing their work, namely, Dr. Timothy transfers some of the polarization to the separated in chemical shift from gaseous Scholl, Dr. Alexei Ouriadov, Dr. Lanette

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 87 away from being able to Laptops for Kenya afford any type of com- Marija Popovic puter education for students. Even a single lap- The Ottawa Cancer Centre top that is many, many years old would give these In a town of Embu, Kenya, about 12,000 children a chance to learn km from here, there is a group of 199 some basic computer energetic youngsters, aged 13 to 19, at- skills. With some luck, tending the Rukira Day Secondary this may be an important School. These kids consider themselves step in helping these to be very privileged because their fami- youngsters achieve great lies are able to afford to pay the annual things in life! tuition, amounting to 325 kg of maize and 360 kg of beans, a school uniform, and to ensuring that the road to success for Please share this message with anyone the valuable time that could be used in- these children is at least a bit less bumpy who may be able to assist us with this stead to help their families work the fields than it was for him. project. I would be more than happy to in this agricultural region of the country. Locally, Mr. Ndwigah is working inces- answer any questions you may have. My Many of these students will be fortunate santly to provide a satisfactory learning email is [email protected]. enough to overcome the challenges re- environment to the children of his birth- lated to poverty, malnutrition, direct and place. He has hosted Dr. Fiona McNeill, indirect effects of HIV/AIDS, and numer- the Associate Vice-President, Research, at ous infectious and potentially lethal child- McMaster University and I in Nairobi in hood diseases foreign to the developed January 2009, and has asked us to help countries such as Canada. They will go with the effort. Dr. McNeill has recruited on to complete high school. Some will a number of ambitious McMaster Univer- even obtain a college diploma or a university students who will spend several sity degree and grow up to be outstanding weeks in Embu in an effort to widen the members of the society willing to give horizons of these youngsters and motivate back to their community. These kids them to demand the most out of life. I have plenty of role models, and Mr. Peter would like to ask you kindly to consider Ndwigah is just one such example. Mr. donating your used laptops for this cause. Ndwigah works at the Institute of Nuclear The local school board is many years Science and Technology at the University of Nairobi and devotes much of his time

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Wire that heats the Rb

Glass cell

Figure 8: Home-built 129Xe optical pumping system. The solenoid provides the magnetic field. Two lasers, which are at the other end of the box and not shown, produce the circularly polarized laser light.

Tanguay, Kundan Thind, and the students the low-field system, Dr. Ravi Menon for Friesen Waldner, Adam Farag, Shayna who presented at the LRCP. Special touring me around the CFMM, Dr. Jerry McKay, Sandra Halko, Mathieu thanks to the following: Dr. William Battista and Dr. Kevin Jordan for touring Boudreau, Marcus Couch, Matthew Fox, Dominguez Viqueira for acting as my me around the LRCP. Miranda Kirby, Lindsay Mathew, Julie guide for the week and teaching me about

88 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale cal physics grant application was being grams available at this site. The notice of NSERC opening up reviewed, up to 5 of the members partici- intent is quite short and applicants are for Medical Physics pating in the discussion (see below) had asked to suggest 5 potential external refe- some medical physics background, which rees, a few of whom should be from out-

a) is much better than in previous years. side Canada. In the end typically 2 of the David W O Rogers and While the competition for funds is fierce, applicant’s suggestions will be contacted. William Whelanb) these grants can be a solid base for fund- Nonetheless the list provided is very use- ing students and so we encourage COMP ful in determining the final set of external members to consider applying. referees. For each grant, the other 3 exter- a) Carleton Laboratory for nal referees are identified by the lead in- Discovery Grants ternal reviewer who is a member of the Radiotherapy Physics, Discovery Grants are baseline grants for Physics EG. The 5 external referees are Carleton University, Ottawa active researchers with academic affilia- the technical experts and their opinions tions. The Discovery Grants (DG) are important. So if you are asked to do a review, either be sure to do it, or inform b) Department of Physics, Program supports ongoing programs of research (with long-term goals) rather NSERC right away that you cannot do it University of Prince Ed- than a single short-term project or collec- so they can potentially get someone else. tion of projects. They provide stable fund- ward Island How applications are evaluated ing for 5 years, in most cases, although st shorter periods may apply in particular Each application is assigned a 1 internal The Natural Sciences and Engineering reviewer, a 2nd internal reviewer and 3 Research Council of Canada (NSERC) circumstances. They are primarily used to fund students, post-docs, travel expenses, readers (hereafter referred to as 5 read- provides almost $1B of funding per year ers). The Physics EG meets in Ottawa in for academic research programs in Can- other routine operating expenses and mi- nor equipment purchases (typically February in what is called a Conference ada. NSERC Discovery Grants (DG) can Model. The members of the Physics EG provide stable 5 year funding to support <$7,000 per item). are divided into sub-groups (called Sec- individual researchers and their research tions) but for specific applications the programs. NSERC Research Tools and The first thing to be aware of is that a notice of intent to apply for a grant is readers may come from different sub- Instruments (RTI) grants support research groups or even from other Evaluation equipment purchases typically costing needed on August 1 and the final application is due at NSERC on November 1 Groups meeting at the same time (e.g. from $7,000 to $150,000. Requests for biology or computing). The idea is to get larger equipment grants are typically di- although most universities have earlier internal deadlines. The applications are as much expertise as possible evaluating a rected to the Canada Foundation for Inno- given application. The technical expertise vation (CFI). We strongly encourage handled on-line via http://www.nserc- crsng.gc.ca. There is also a wealth of data comes from the external referee reports as Canadian medical physicists to investi- well, hence their importance to the proc- gate these programs for possible research and information about the various pro- funding related to natural sciences or engineering advances in medical physics as 18% opposed to clinical/patient based research 16% which is funded by the Canadian Insti- tutes of Health Research (CIHR). 14% NSERC has recently changed its proce- 12% dures for reviewing their baseline grant Funded ECR programs, (i.e. DGs and RTIs). The purpose of this article is to briefly outline the 10% Funded ER DG and RTI programs and to provide 8% Unsuccessful ECR some tips on grant writing. We do this as Unsuccessful ER two members of the Physics Evaluation Percentage 6% Group (EG) which reviewed all of the physics DG and RTI grant applications 4% for 2010 (with the exception of sub- 2% atomic physics). 0% Perhaps the most important piece of news ECR - Early Career I is that Medical Physics is now a recog- D E F G H J K L M N-P Researchers; nized “Research Topic” within the A - C ER - Established NSERC Physics EG review structure Quality Category Researchers (identified as PHYS08), and it is separate from Biological Physics (identified as PHYS09). In conjunction with that, in the Figure 1: Distribution of applicants into bins for the Physics Evaluation Group in the 2010 competition there were 6 medical 2010 competition. Bin J corresponds to a score of 12, e.g., equivalent to 3 “Strong” rat- physicists on the Physics EG (out of 40 ings (from NSERC’s ``2010 Competition Statistics: Discovery Grant Program’’ available members). This means that when a medi- on the NSERC web site).

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 89 ess. 165.1 - 170 Each application is evaluated on 3 crite- 155.1 - 160 ria: the Scientific or Engineering Excel- 145.1 - 150 lence of the Researcher(s), the Merit of 135.1 - 140 the Proposal and the Contribution to 125.1 - 130 Training of Highly Qualified Personnel 115.1 - 120 (HQP). Note that each criterion has equal 105.1 - 110 weighting, so that the contribution to 95.1 - 100 training of HQP has the same weight as 85.1 - 90 the excellence of the researcher. The rat- 75.1 - 80 ing is on a six point scale: Exceptional 65.1 - 70

(1), Outstanding (2), Very Strong (3), Grant levels ($K) 55.1 - 60 Strong (4), Moderate (5) and Insufficient 45.1 - 50 (6). We did not see the Exceptional rating 35.1 - 40 used for any of the 60 or so applications we were directly involved with. Details of 25.1 - 30 the criteria used are available on the 15.1 - 20 NSERC web site but in practice it comes 10 or less down to a discussion between the 5 read- 0 100 200 300 400 500 ers of any given application. The “Outstanding” level implies a very ac- Number of successful applicants complished researcher. In the 2010 competition, receiving 3 “Strong’’ ratings was Early Career Researchers Established Researchers not a guarantee of funding due to the stiff competition. Figure 2: Distribution of NSERC Discovery Grant amounts for the 2010 competition for all disciplines except sub-atomic physics (from op.cit.). The discussion of each application lasts for about 15 to 20 minutes and only the 5 liquid He is needed to run an MRI, an In the 2010 competition, if one includes readers are allowed to speak. There is extra $5K/y may be allocated but the ap- the Subatomic Physics Individual and then a confidential vote on each of the 3 plicant would be expected to get the rest Team grants, there were 223 applications criteria and the median value of the 5 of the costs from other grants or their own to the Physics EG (which included most votes is used to assign the rating for each institution. but not all of the medical physics grants). component (for example, the median rat- There were 139 grants awarded for a suc- ings may be Very Strong (3), Strong (4), Once all applications have been reviewed, cess rate of 62% and an average grant of Strong (4) for a total score of 11). It each application is placed in one of 16 $40,800. Early career researchers (ECRs) should be pointed out that NSERC is very funding bins (A-P) based on its score re- are reviewed using the same criteria as all careful about conflicts of interest, so, for sulting from the merit assessment of the other applicants, except that greater em- example, any member of the Physics EG three criteria. Figure 1 shows the distri- phasis is placed on the “potential” to must leave the room when the application bution into bins in this year’s competition make significant contributions to research of any faculty member from the same for the Physics EG. For example, bin A and to the training of HQP. In the 2010 university or that of any collaborators is has a score of 3 and refers to 3 Excep- competition there were 20 ECR applica- to be discussed. tional ratings whereas bin J has a score of tions of which 16 were funded for an av- 12 and refers to 3 Strong ratings or 1 erage grant of $34K. During the review process there is little Strong, 1 Moderate and 1 Very Strong, consideration of the proposed budget etc. The grant amount awarded is the Advice unless it has something wildly out of same for all applications in a given bin. It Applications to the Discovery Grant Pro- place (e.g. an excessive travel request or is important to note that EG members do gram must be focused on the natural sci- an equipment request worth more than not discuss individual grant amounts. ences and engineering (NSE). Reviewers $7,000 which should be directed to the Preliminary bin values are assigned based are directed to consider only those aspects RTI program). This reflects the philoso- on the previous year’s competition and of the proposed program related to NSE. phy that Discovery Grants are primarily they are later modified after the bins are Hence, for medical physics applications used for funding students, post-docs and populated with applications in order to this means that if the proposal is deemed basic operating costs such as conference balance the budget and success rate in the to be more clinically oriented this may travel, so the actual grants awarded are context of a highly competitive competi- affect the rating for the “Merit of the Pro- independent of the funds requested. tion for limited resources. posal”. Hence, it is important to stress the There is a slight perturbation on this NSE discovery / innovations. whereby the evaluators consider whether Funding levels the cost of a particular line of research is NSERC Discovery Grants range in value The awarded amount on a successful more or less expensive than typical re- from about $10K/y to a very few over grant application cannot be more than search in physics, and then there may be a $100K/y with an overall median of $25K what was requested, even if the applica- slight supplement (or decrement) to the to $30K/y. Figure 2 shows the distribution is placed in a higher funding bin. Be grant (of the order of 10%). So, e.g., if tion of grant amounts for all disciplines. sure to build a budget based on the actual

90 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale costs for the proposed research program ences and engineering research. We en- various splinter republics to redirect and be sure to provide a detailed budget courage medical physicists who have ac- their technical, and often classified and justification. The budget should not be tive research programs with this focus, or secretive, skills towards peaceful scien- inflated as this may affect the rating for a good idea for a research program and tific ends. The idea of their integration the “Merit of the Proposal”. For medical desire to fund graduate students, to apply into the larger international scientific physics applications it is very important to NSERC for some baseline funding. community obviously serves the inter- to discuss any scientific or budgetary est of the contributing Western democ- overlaps with other health related grants Interesting Things racies, in minimizing the risk of various and funding sources, such as CIHR. biological/chemical/nuclear/rockets/

submarine weapons expertise and tech- If the applicant has no or a limited track Medical Physicists nologies falling into the ‘wrong hands’, record of supervising graduate students, Do: Swords into requesting funds to supervise a large however these are defined by the politi- number of students (e.g. 5 or more) may Ploughshares?! cal contingencies of the day (Rogue be viewed as unrealistic. Since training states? Extremist groups? Militia units? of HQP is so critical in the evaluation, it Dr. Alex Vitkin, MCCPM I don’t want to expound on this contro- is important for applicants to establish a University of Toronto versial designation…). Hence the unof- track record of supervising graduate stu- ficial name of this whole venture, dents prior to submitting an application A medical physics phenotype is inter- Swords into Ploughshares, referring to (except for early career researchers who disciplinary by his/her very nature. We converting weapons scientists into are evaluated more on what is proposed, need to be conversant with various as- peaceful scientists; the tank/tractor as well as any experience co-supervising pects of physics, engineering, biology analogy mentioned above is my own students). Proposals should include a and clinical sciences through the daily current adaptation of the ancient S-into- HQP training plan that includes details on demand of our exciting profession. As P Biblical phrase. the student experience including, for ex- such, some of us serve as grant review- ample, presentation at COMP and other ers on different research grant panels – So what does all this mean practically, scientific meetings. NSERC, CIHR, NCIC/CCSRI, NIH, especially for a harried medical physi-

NSF just to name a few of the more cist such as myself? Well, every sev- Given how the application will be evalu- common relevant abbreviations. But eral months an NSERC representative ated, it is important to give the reviewers sends us a list of applications that have specific evidence and information related did you know that there is also an inter- been submitted by various research to the three criteria. Things should not be national granting (“redirecting”) pro- groups in Russia, Ukraine, Belarus, blown out of proportion, and excessive gram whose unofficial motto is “Turn wordiness is a no-no (each member of the Swords into Ploughshares”!? (or Georgia, Armenia, Moldova, Azerbai- EG is reviewing a large pile of applica- “Tanks into Tractors” for those with a jan, Kazakhstan and other central Asian tions). However, it is important to give more modern agricultural bend:) The republics. Having indicated our rela- specific examples such as external invited Canadian government, thru the Depart- tive comfort levels for review – and talks, memberships on external task ment of Foreign Affairs and Interna- here the panel members have to stretch groups or scientific committees, commer- tional Trade (DFAIT -- for funding), their expertise and imagination consid- cial or clinical use of the applicant’s and thru NSERC (for the scientific peer erably, as the range and scope of topics work, external collaborations, highly cited -review process), plays a major role in in the different proposals is really papers, book chapters or reports, review- this innovative international venture. REALLY wide – we convene in Ottawa ing or other roles for high impact jour- For the last few years, I have served on for a day or two and conduct our re- nals, etc. It is important to remember that this panel and have found it quite wor- view. Here, in addition to the more each application is rated in comparison to thy, not well known to my colleagues, conventional research grant criteria the cohort of grants submitted in that and in many ways ‘off the beaten path’. such as significance, innovation, and competition year. So I decided to write a short piece for methodology, we consider aspects par- InterACTIONS to share this interesting ticular to this funding program, such as: Applicants should get several colleagues experience with the medical physics does the research involve a significant to read their application. It must be well community. number (>50%) of former weapons sci- written, again remembering the impres- entists? is the proposed science truly sion it will make on a busy reviewer/ ‘peaceful’, or may it still have a mili- reader if he/she has to struggle to read the In essence, this is a program put to- tary/weapons component or applica- document. gether by the Western world in the 1990s, following the collapse of the tion? does the proposal have any par- Summary communist block and the aftermath of ticular economic (or security) signifi- In 2009 NSERC formally recognized the Cold War. The European Union, cance to the sponsoring parties Medical Physics as a Research Topic United States, Japan, Australia and (presently Canada, USA or EU)? will within the Discovery Grant (DG) Pro- Canada have pulled together some this enable a transition to a long-term gram. Medical physics applications are a funds (don’t ask me about the compli- self-sustained peaceful operation? As good fit with the DG program provided cated bureaucracy of this aspect!) to you can well imagine, these are pretty that the proposed research activities are enable selected “weapons scientists” unusual evaluation criteria unfamiliar to within NSERC’s mandate of natural sci- from the former Soviet Union and its most of us, so the discussions can get Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 91 interesting, lengthy, and convoluted. Add to this the extreme range of dispa- rate expertise on the review panel Welcome New COMP (nuclear, solid state, laser and medical physicists; chemists and biochemists; agricultural, electrical and aeronautical Full Members engineers; biologists and clinical scientists; entrepreneurial, industrial and First Name Last Name Institute government scientists, etc) and the often ‘unconventional’ writing style of the Malik Brunet-Benkhoucha Hôpital Maisonneuve-Rosemont proposals (the applicants are writing in their non-native language, and many Matthieu Lemire Hôpital Maisonneuve-Rosemont have never applied for a research grant Ryan Rivest CancerCare Manitoba in their careers; a promise to exceed the Mark Ruschin Princess Margaret Hospital targets of the Central Committee’s five Gabriel Sawakuchi Carleton University year plan would have often sufficed in the past!), and you have more reasons Steven Thomas BC Cancer Agency - Abbotsford for a lively discussion. The NSERC Rebecca Thornhill Ottawa Hospital officers and the DFAIT representatives Roxana Vlad Durham Regional Cancer Centre present during our panel deliberation try Ling Bin (Mark) Xu Best Theratronics to reign us in, sometimes successfully!

But let’s cut to the chase, what kind of grants do we actually get to review? Associate Members On a given day, we may discuss proposals dealing with algae use for clean- Désiré Ngambia Mbamou ing up chemically contaminated soil, Stephen Pinter Robarts Research Institute use of weapons tracking technology to Aaron Ward Robarts Research Institute optimize commercial railway transport scheduling, novel rotor design for advanced helicopters, low-level electro- magnetic irradiation of crop seeds to Student Members increase yield, radioactive nanoparticle use in biomedicine, magnetic warning Andrew Alexander McGill University system for lightning interference with Muhammad Naeem Anjum McGill University technology installations, advanced de- Alexandra Bourgouin Université Laval tection of cosmic ray bursts, lab-on-a- Alexandra Bourque Université Laval chip approaches for tuberculosis diagnosis, laser biostimulation for speeding Lada Bumbure Riga Technical University up mushroom growth (huh?!), and so Derek Cappon McMaster University on. Interesting you say? Yup! Varied/ Eve Chamberland Hôtel Dieu de Québec (CHUQ) crazy/difficult to evaluate? Ditto. But Heather Champion CancerCare Manitoba overall useful and worthy? Lets’ see – trying to change mindsets, manage dan- Carling Cheung Robarts Research Institute gerous hardware, clean up environ- Eunah Chung McGill University mental disasters of the Cold War vin- Robert Cropp BC Cancer Agency - Vancouver tage, enable long-term peaceful sustain- Charlotte Curtis University of Calgary ability and coexistence, etc… Useful indeed, I think!!! Michel D'Amours Université Laval Maxime Desbiens Hôtel Dieu de Québec (CHUQ) With respect to the last point, NSERC/ Claire Foottit Carleton University DFAIT have tried to derive some Jean-Christophe Gagnon Hôtel Dieu de Québec (CHUQ) ‘success metrics’ to evaluate the effec- tiveness of this program. This is not an Jean-François Gauthier Université Laval easy undertaking even for conventional Mathieu Goulet Hôtel Dieu de Québec (CHUQ) granting programs such as NSERC or Chad Hunter Carleton University NIH, and even more difficult here. So Amjad Hussain Tom Baker Cancer Centre the objective evaluation of the utility of Swords into Ploughshares program is (Continued on page 94)

92 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale such as points, lines, rectangles, cir- cles and rings etc. They can be used Members! to construct parallel, collimated or other types of sources. There is also a Gaussian shape to model non- uniformly irradiating sources. Multi- ple sources can be combined to form

John Kildea McGill University a collection of sources where each Izabela Kowalczyk Robarts Research Institute individual source can be assigned a Karl Landheer Carleton University statistical weight. François Lessard Université Laval Daniel Markel Odette Cancer Centre Epp and the EGSnrc C++ class library are written in C++ and are designed to Matthew Marsh Queens University be easily modifiable and extendible. Peter McCowan CancerCare Manitoba If, for example, the user requires a Jonathan Morin Université Laval particle source that cannot be constructed with the provided shapes, she Jennifer Moroz University of Alberta Munira Fardous Nahin Carleton University can implement a new shape based on an existing one. The user only needs Nick Rawluk Queens University to implement the new aspects of the Micheal Roumeliotis University of Western Ontario shape and can rely on the base func- Christine St-Pierre Université Laval tionality of the existing shape. The Justin Sutherland Carleton University same applies to simulation geome- An Wang University of Western Ontario tries. To simply use Epp in its current form, no programming whatsoever is required. Corporate Members The input file for Epp consists of key- Dragani Amy NELCO value pairs in a keysubkey structure, Marlay Ian Maquet-Dynamed Inc. which makes it very flexible and human readable. Epp also provides the solid and extensively validated phys- ability to reference other files so that Easy Particle ics model and the framework of the a simulation can be broken up into Propagation Monte Carlo simulation. In addition several input files, which can be re- used and shared among users. Jonas Lippuner to that, Epp is based on the EGSnrc C++ class library, which provides a CancerCare Manitoba comprehensive library of geometry To simulate x-ray imaging, the user objects that can be used to create sim- defines a virtual detector, which is Epp (Easy particle propagation) is a ple as well as very complex simula- basically an image plane with a given user code for the Monte Carlo simulation geometries. The simulation ge- size and number of pixels. Epp will tion package EGSnrc. Epp is designed ometry is constructed from primitive then propagate all photons that leave for x-ray scatter analysis in x-ray im- geometries, such as planes, boxes, the simulation geometry to that image aging applications. It simulates radia- spheres, cylinders and cones. These plane and score the number of pho- tion transport through an arbitrary objects can be arbitrarily positioned, tons and/or the total deposited energy geometry and propagates the particles rotated and combined to form more in each pixel. Epp can create five dif- that leave the simulation geometry to complex structures. Defining the ferent images, namely one for pri- an image plane where a picture is simulation geometry in this analytical mary, single Compton, single formed. Epp also tracks the number of way has the advantage that it is more Rayleigh, multiple scattered photons, Compton and Rayleigh scatter events accurate and in most cases also much and one image with all photons. Epp that a photon undergoes and creates faster to simulate. Voxelized volumes can also calculate the dose deposited separate images for primary and scat- can also be integrated into the simula- in each voxel of a voxelized volume. tered photons. Currently, Epp only tion geometry and can be directly im- Epp is released under the GPL license propagates photons, but it could be ported from an existing *.egsphant and freely available at http:// easily modified to propagate other file. www.physics.umanitoba.ca/~elbakri/ particles as well. epp. In a similar fashion, particle sources The EGSnrc code system provides a are constructed from abstract shapes,

Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale 56(3) juillet/July 2010 93 Editor’s Note Idris Elbakri, PhD, MCCPM CancerCare Manitoba, Winnipeg, MB

This issue of InterACTIONS is jam the opportunity it presents us to reach packed with quite the variety of arti- out beyond our cubicles and make the cles: from laptops for Kenya to turn- case for the diagnostic imaging ing swords into ploughshares! These branch of medical physics. colleagues who take the initiative and write make my job as editor so much I hope you all have a pleasant sum- easier. I can focus on layouts and mer. The next issue is in October. The graphics and do not have to worry deadline is September 1! about chasing after content from the membership. (Continued from page 92)

I am writing this column just a few not an issue I have sufficient expertise in. days before the COMP/CCPM annual (Does anyone? I wonder) Personally, meeting in Ottawa. The LAC has pre- however, and time commitment consid- pared a very interesting program for erations aside, I thoroughly enjoy the Dates to Remember camaraderie of our review meetings and us. I will be looking for volunteers to write a review of the annual meeting! the intellectual stimulation of learning

many new concepts at each panel gather- In the wake of public attention to CT ing. Given the highly interdisciplinary InterACTIONS Fall doses, the AAPM held a “CT Dose nature of the panel, the tongue-in-cheek Summit” in Atlanta, GA at the end of trash talking is inevitable – chemists rule Issue Deadline is April. I had the pleasure of attending vs physicists rock vs clinicians are tops September 1, 2010! vs biologists know best vs engineers the meeting. It was an intensely fo- make it work vs … Well, you get the cused meeting on all aspects of CT idea! The overall positivity is further dose reduction. Topics included pro- bolstered by my firm conviction that ‘this AAPM Annual Meeting tocol optimization, cardiac CT, kVp is the right thing to do’, both in the pro- selection, etc...One of the most impor- grammatic context, and in the personal July 18-22, 2010 tant lessons learned from the meeting context of contributing my expertise Philadelphia, PA was the need for dose reduction and (such as it is:) for a worthy scientific optimization to be a collaborative cause of truly global significance! team effort. This seems obvious, but to a clinical imaging physicist like If anyone is interested in learning more AAPM Summer School myself, is not easy. Unlike our ther- about this initiative, its official name is July 22-25, 2010 apy colleagues, imaging physicists in Global Partnerships Program IGX, with Canada are not always “embedded” in other relevant abbreviations being ISTC: Philadelphia, PA the clinical environment. Here in International Science and Technology Winnipeg, we are part of the Division Centre of Russia and STCU: Science and International Conference of Medical Physics at CancerCare. Technology Centre of the Ukraine (these on 3D Radiation This arrangement has both pros and identify from which different competition cons, but one challenge is to persis- centres within IGX the applications are Dosimetry tently reach out to the radiology com- coming from – see http:// August 22-26, 2010 munity and convince them that our www.international.gc.ca/gpp-ppm for Hilton Head Island, SC services are of value. Other imaging more details). In the meantime, if anyone is interested, we’re often looking for ex- physics services in Canada are found pert reviewers to help us evaluate a par- in a more regulatory/radiation protec- RSNA Annual Meeting ticular grant, and sometimes we seek new tion type environments, which also members to serve on the panel too. November 28- remains a bit isolated from clinical December 3 stakeholders. One positive conse- Happy scatterings! Chicago, IL quence of the recent public attention towards doses from CT and radiation in general is

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96 56(3) juillet/July Canadian Medical Physics Newsletter / Le bulletin canadien de physique médicale