Meeting The Joint Commission’s Outline Fluoroscopy Training Requirements • Overview of TJC’s recent fluoroscopy requirements Part I: Image Gently, Image Wisely and Dose Optimization • Basics of radiation units, terminology and regulatory limits • Radiation risks in fluoroscopy, their prevalence and probabilities • Physical and operational aspects of fluoroscopes Satish Nair Ph.D, CHP, DABMP Certified Health Physicist • Best practices in fluoroscopy: for patients and operators Certified Medical Physicist

F. X. Massé Associates, Inc. Health and Medical Physics Consultants Gloucester, MA

fxmasse.com

20th Annual SRPE Educational Conference, Las Vegas, NV April 2019

1 January 2019 Terminology Convert to Equivalent dose (mrem, mSv) X-ray , Gamma, Beta = 1 Alpha = 20 Proton = 2 Head CT Neutron = 5 to 20 Cardiac Exposure Stress Test

KUB Image Gently: ‘Pause and Pulse’ resources X Ray 1 January 2019 • Annual Medical Physics evaluation of fluoroscopes • Designated Radiation Safety Officer (RSO) Measure Exposure Extremity X Ray • Dose indices stored in retrievable format: CAK or KAP - if displayed Roentgen Compare to NB Convert to R, mR, mR/h If not displayed: cumulative fluoro time and # of digital spot images Calculate Radiation Effective Dose (Whole Body Dose) • Establish radiation exposure and skin dose thresholds for adverse effects Absorbed dose to organ • Perform evaluation if exceeded these thresholds are exceeded Roentgen equivalent man Roentgen absorbed dose rem, mrem, mrem/year rad, mrad 1 July 2018 Sievert: Sv, mSv • Use of shielding in fluoroscopy Kerma (kinetic energy released per unit mass) Gray: Gy, mGy, mGy/min • Quarterly review of dosimetry records (exemption: office based practices)

PSE 25,000 DDE, 75,000 LDE, Radiation by the numbers High Dose Fluoroscopy Risk: Deterministic 250,000 SDE lifetime Stop Working (for rest of yr) (mrem) Secondary ulceration SDE 50,000: Oragn / extremity / skin limit Dermal necrosis Ramsar (Iran): Moist desquamation 26,000 mrem/y

Telangiectasis Guarapari (Brazil): 5000: ALARA for SDE Stop Working 17,000 Dermal atrophy (for rest of yr) LDE 15,000: Lens of the eye limit High Background Dry desquamation Radiation Areas HBRAs Permanent Kerala (India) epilation 1,500: ALARA for LDE Stop Working Yangjiang (China): (for rest of yr) 7000 Temporary DDE 5000: Whole epilation Main erythema body dose limit Badging 500: ALARA for whole body dose FDA / CDRH 1995 Early transient erythema (gen pub: infrequent exp) Training 100: General public limit Denver, Regulatory 2 4 6 8 10 12 14 16 18 20 Gy Colorado: 450 Continental Trigger Level: 200 600 1000 1400 1800 2000 rad USA: 300 World average 1, 2, 3 Gy Australia: 170 240 mrem/y 100, 200, 300 rad TJC Sentinel Event Alert (1500 rad) Skin Reactions and Follow up How common are fluoroscopy skin reactions ? No effects observed (Balter et al., 2010) 0 to 2 No notification; No effects observed Gy (0 to treat for signs 200 No effects observed and symptoms L E G E N D rad) No effects observed Prompt: < 2 weeks Tsapaki, V., and M. Rehani Skin Early: 2 to 8 weeks Advise to AJR: 203, W462-463, 2014 Transient erythema patient; follow- Possible erythema Dose Midterm: 6 to 52 weeks 2 to 5 Epilation should fade with up actions Gy (200 time; treat for Long term: > 40 weeks Recovery from hair loss Radiation induced skin injuries: rare complication to 500 physical discomfort rad) No effects observed Frequency estimate: between 1 in 10,000 and 1 in 100,000 procedures

Transient erythema Have patient / caregiver examine for 2-10 5 to 10 On average ~10 reported cases in US per year from ~ 10 million Erythema, Epilation weeks for skin effects; Gy (500 interventions to 1000 Recovery / prolonged erythema / Permanent partial Possible dermatologist’s consultation’ epilation rad) Recovery / Dermal atrophy or induration Inform treating physician about irradiation 1993 to 2001: 73 severe cases reported worldwide

Transient erythema All of the above, + 10 to 15 Erythema, Epilation, Dry or moist desquamation with 80% from cardiac procedures; remaining from radiology and neuroradiology. Gy (1000 recovery Prophylactic treatment for infection; to 1500 Prolonged erythema; permanent epilation Monitoring of wound progression, if needed rad) Telangiectasia / dermal atrophy or induration / weak skin ~ 1 case is filed in a US court of law every 4-5 weeks for skin injuries

Transient erythema / edema and acute ulceration / long term surgical intervention possible All of the above; > 15 Gy A single operator, performing ~ 1000 cases per year: may not see any burns Erythema, Epilation, Moist desquamation Ulceration or necrosis (> 1500 in their processional career rad) Dermal atrophy / Secondary ulceration / Dermal necrosis. Surgical intervention likely possible. Telangiectasia / dermal atrophy or induration / Late skin breakdown with deeper lesions. Surgical Intervention

Fluoroscopy systems Minimum Source to Skin Distance Allowed ALL ROUTINE PROCEDURES C-Arm IMAGING ASSEMBLY Image Intensifier or Digital Detector 30 cm

CERTAIN SPECIFIC SURGICAL APPLICATIONS

SID: Source to Image Distance FS to Detector 90 – 120 cm 30 cm 20 cm SSD: Source to Skin Distance

X RAY TUBE Filtration HOUSING ASSEMBLY

Fluoroscopy: Output Limits and Locations AKR and CAK display Dose at the point of entrance of beam into patient

C-Arm Required for equipment manufactured after Input surface of imaging assembly 10 June 2006 Dose sticker KERMA = Kinetic Energy Released in MAtter Maximum output Allowed: or Kinetic Energy Released per unit MAss 10 R/min for Normal fluoro ‘AK Reference Location’ (88 mGy/min) • AKR = Air Kerma Rate 30 cm 20 R/min for Boost fluoro mGy/min mGy/sec Gy/sec (176 mGy/min) accuracy: + 35% of actual values for rates > 6 mGy/min Recording (cine): no limits (error can be > + 35% for dose rates < 6 mGy/min) ‘Compliance Location’ • CAK = Cumulative Air Kerma mGy Can be 100 times regular fluoro dose accuracy: + 35% of actual values for rates > 100 mGy Skin dose assessment thresholds: (error can be > + 35% for dose rates < 100 mGy) State of MA = 2 Gy State of RI = 1 Gy - Generally not a measured reading Veterans Administration = 3 Gy - Calculated based on algorithms (kV, mA, pulse width) ICRP recommendation = 3 Gy Society of Interventional Radiology = 3 Gy Fixed - Not inverse square corrected (Philips, GE, Siemens) TJC Sentinel Event Alert = 15 Gy C-arms - Inverse-square corrected on AP plane (Toshiba) Displayed AKR and CAK vs. Compliance Locations Patient Position vs. AKR

Undertable Fluoro Overhead Fluoro

120 Exposure (R/min) 30 cm 0 51015 20 25 1 cm 90 above TT 30 cm Above TT 80 AK Ref. location = Compliance Location AK Ref. Location = 70 50 mGy/min Compliance Location

Portable C-Arm 60 +35% ‘Fixed’ C-Arm Different for: 50 Philips FD-10 Philips FD-20 Source to skin (cm) 30 cm Siemens 40 below II GE 15 cm Toshiba 30 below Isocenter AK Ref. Location = 30 cm Compliance Location Ref. location closer to tube FS than compliance location

Dose Area Product (DAP) or What determines patient dose? Kerma Area Product (KAP) displays: Technique factors (kV, mA, time): Thickness of anatomy (AP vs. Oblique angles) Dose x surface area of collimator Choices made by the fluoroscopist – Operating mode (continuous / pulse / boost / cine) Frame rate / protocol Variety of units: Collimation 2 2 2 2 2 mGy·cm Gy·cm rad·cm cGy·cm Gy·m Field of view (open field vs. mag field) mGy·m2 Gy·m2 Gy·cm2 Table height during procedure (x-ray tube – to - skin distance)

Accuracy: + 50% Dwell time on skin (with respect to skin reactions) (+ 35% since 2010) Applicable to European regs., not US FDA regs. Thickness of table and cushion (with respect to displayed AKR, CAK) - Either measured real-time using flow-through ion chamber OR calculated

Technique Factors Operating Modes I need more The Trinity: • Auto mode (AERC): kV and mA (and sometimes filtration) selected by machine photons ! • Manual Mode: User selects kV, mA kV mA time

Energy # of photons - foot pedal time • Normal Mode: x kV x mA x dose # of photons - frame / pulse rate • Boost Mode (OHLC, HLF): x kV ~2x mA ~2x dose - pulse width • Record mode (Cineradiography; cinefluoroscopy digital cine): higher kV, mA, dose dose: slightly higher to > 100 times higher • Last Fluoro Loop Replay (LFLR): no additional dose • Digital Spot Image (photospot recording, ‘spot film’) Automatic Brightness • Last Image Hold (LIH): Fluoro Save / Fluoro Grab no additional dose Control (ABC) system Frame rate • Continuous Fluoro 7.5 fps • Pulse Fluoro 15 fps 70 to 90% dose reduction

Pulse width (eg., at 15 fps) Practice ‘Tap Fluoroscopy’ 3 ms 10 ms Magnitudes of Fluoro vs. Cine dose Patient Positioning and Grids

50 – 120 x

15 x 10x 1.3x 1.2x

5x 13 x 3x Pb grid: More dose (~ 25%) Closer: Less dose Fixed C-Arm patient Thicker: More dose Mini C-Arm Philips Allura FD10 Oblique view: More dose Hologic Insight Cine ~ 13 to 15x Fluoro dose Cine ~ 1.3x Fluoro dose 14 (both @ 15 fps) Away: Less dose Portable C-Arm Fixed C-Arm GE 9900 Siemens Artis Zee Radiotransparent, thin table, air Cine ~ 3 to 10x Fluoro dose Cine ~ 50 to 120x Fluoro dose (Cine @ 30 fps cushions Fluoro @ 3 fps)

The Good, the Bad and the Ugly More Collimation: Less Dose Beam Much capture Less Scatter Beam More scatter dose Better contrast

Less Beam scatter dose More Fig. 15. Virtual collimators work by drawing an outline of the collimated dose area

Tall / Medium Operator Short Operator on Pallet Short Operator Virtual Collimators

Virtual collimator boundary

Less Magnification: Less Dose Dwell Time on Skin Less Scatter Better contrast larger area2 = x times dose smaller area2

eg. 10” / 8” / 6” setup:

open – mag 1: 102 / 82 = 1.6x dose mag 1 – mag 2: 82 / 62 = 1.8x dose Open – mag 2: 102 / 62 = 2.8 x dose

Digital detectors:

10” to 8” 1.3x dose Caution: avoid overlaps 8” to 6” 1.4x dose move arms out of the way 10” to 6” 1.5x dose Balter et. al. 2010, 15-20 Gy Twelve things you can do to decrease patient dose Radiation Safety Principles • Maximize source – to - skin distance 100 100

• Minimize imaging assembly – to - skin distance 80 Time 75 Distance Dose reduction 60 75% 89% 93.8 % 96% 99.96% • Use appropriate frame rates; go as low as practicable 50 (1') (2') (3') (4') (45') 40

Dose (mrem) 25 • Take the foot off the pedal when not viewing the display (mrem)Dose 20 • View the freeze-frame image (LIH) instead of the live image 0 0 10 8 6 4 2 0.1 0 10 20 30 40 50 0 10 20Distance 30 (feet) 40 50 SlideWrite Plus - Advanced Graphics Software, Inc. • Minimize use of boost and record modes Time (min) Distance (feet) Order: www.SlideWrite.com 800-795-4754 Fax: 760-634-8363 • Utilize Fluoro Grab and Last Fluoro Loop Replay Ceiling Shield, • Collimate tightly to the area of interest Tableside drapes: well over 95% protection 100 Shielding • Use Large (‘Open’) Field of View 80 0.5 mm Pb eq. lead protective garment: 60 > 95% protection • Magnify only when necessary 40 Dose reduction 92% 95% 97.5% 99.5% 1 mm Pb eq. lead protective garment: • Move the skin-entry point of the useful beam (mrem)Dose 20 Only an additional 1-2% protection 0 • Pay heed to 5-minute alarms and accumulated dose 0 0.25 0.35 0.5 1.0 Doubling lead garment thickness Lead apron thickness (mm) Lead apron thickness (mm) DOES NOT double your protection Practice ALADA: As Low as Diagnostically Adequate

Operator Dose Orientation vs. Scatter

With apron: Scatter is reduced Ceiling patient > 95% shield

Less Scatter 20 – 50 mR/hr (~ 5x) patient More Scatter

Location vs. Scatter

0.2 / 1.8 50 – 200 mR/hr (>99% dec) 1’ 150 mR/h fluoro / 880 mR/h cine (5.9x) 2’ 1 foot Scatter Profile 60 / 370 20 / 120 5 / 40 (no apron) (60% dec) (85% dec) (95% dec) Tableside apron

Twelve things you can do to decrease your dose References • Anything you do to decrease patient dose will decrease operator dose Balter, S., J. W. Hopewell, D. L. Miller, L. K. Wagner, and M. J. Zelefsky. 2010. • Take a few steps away from the primary beam Fluoroscopically guided interventional procedures: A review of radiation effects on patients’ Skin and Hair. Radiology 254 (2): 326-341. • Diligently wear and store lead protective garments • Use leaded goggles / glasses (anyone within 1 meter of the primary beam) Tsapaki, V, and M.M. Rehani, 2014. I perform more than 100 interventional procedures • Make full use of tableside lead curtains and ceiling shield every year but have never seen radiation induced skin injury: Am I missing something? AJR 203: W462-W463. • Ensure that the tableside lead curtains are not falling apart • Inspect lead garments annually for holes, cracks, tears by x-raying • If hands are close to primary beam: 0.5 mm Pb gloves • Stand on the Detector side instead of tube side (for non-AP orientation) • Use portable lead shields to the extent possible (for Cine) • Rule of thumb: Patient’s skin entrance exposure is 1000 times the scatter at 1 meter perpendicular to primary beam • KNOWLEDGE: Wear badges properly and track your dosimetry results

Practice ALARA: As Low as Reasonably Achievable ALARA for me ALADA for you

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Thank You