7/30/2018. Paid Speaker, Bayer. Radiology Cardiology Interventional Endoscopy Pain Medicine Speech Language Pathology Surgery List is longer than this

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1 (Public Domain) 7/30/2018 William F. Sensakovic, PhD, DABR, MRSC Medical Physicist Florida Hospital Co-Founder, Telerad Physics Teaching, LLC Assoc. Prof. University of Central Florida Clin. Asst. Prof. Florida State University Adj. Prof. Adventist University Paid Speaker, Bayer (Public Domain) 2 Radiology Cardiology Interventional Endoscopy Pain Medicine Speech Language Pathology Surgery List is longer than this 3 1

2 Effect Threshold Onset Transient Erythema 2 Gy Hours Temporary Epilation 3 Gy 3 Weeks Main Erythema 6 Gy 10 Days Permanent Epilation 7 Gy 3 Weeks Dry Desquamation 10 Gy 4 Weeks Invasive Fibrosis 10 Gy Dermal Atrophy 11 Gy > 14 Weeks Telangiectasis 12 Gy > 52 Weeks Moist Desquamation 15 Gy 4 Weeks Late Erythema 15 Gy 6-10 Weeks Dermal Necrosis 18 Gy > 10 Weeks Secondary Ulceration 20 Gy > 6 Weeks Wagner LK, Eifel PJ, Geise RA. Potential Biological Effects Following High X-ray Dose Interventional Procedures. Journal of Vascular and Interventional Radiology 1994; 5: Stent 22 min fluoro time 6 mo later failed recanalization 47 min fluoro time 2 d later implanted two more stents 78 min fluoro time Banic B et al. Thoracic Radionecrosis Following Repeated Cardiac Catheterization. Radiology Research and Practice Volume Not significantly more radiosensitive than adults. UNSCEAR 2013 Vol.2 Anx.B More sensitive for epilation Less sensitive to moist desquamation 6 MacLeod, J. M. H., The Treatment of the Scalp by X-rays, BMJ, 1905, ii: 14. 2

3 We don t have peak skin dose More on this later Currently have dose index cutoffs instead Stecker MS, Balter S, Towbin RB, et al. Guidelines for patient radiation dose management. J Vasc interv Radiol 2009; 20:S263-S Fluoroscopy Time In DICOM Header? Runs All Sent? Photospots/Spots All Sent? Chida K et al. AJR 2006;186:

4 1 min of Cine = 10 min of fluoroscopy 1 min of DSA = 30 min of fluoroscopy Your mileage may vary CCO;Public Domain 10 Total Energy Delivered Best for Effective Dose Correct to get field size at patient entrance Dicom in dgy*cm 2 Maybe Chida K et al. AJR 2006;186: Air Kerma at IRP No Backscatter Best Correlation with Peak Skin Dose Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study Part II: Skin Dose. Donald L. Miller, MD, Stephen Balter, PhD, Patricia E. Cole, PhD, et al. J Vasc Interv Radiol 2003; 14:

5 PSD vs. K a,r 60% Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study Part II: Skin Dose. Donald L. Miller, MD, Stephen Balter, PhD, Patricia E. Cole, PhD, et al. J Vasc Interv Radiol 2003; 14: Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study Part II: Skin Dose. Donald L. Miller, MD, Stephen Balter, PhD, Patricia E. Cole, PhD, et al. J Vasc Interv Radiol 2003; 14: Several automated and semi-automated methods currently under construction Tedious to try to do it all by hand 14 DICOM compliance is the Wild West for IR/Fluoroscopy Information missing or wrong Especially outside radiology/cardiology 15 5

6 Compagnone G 1, et al. Calculation of conversion factors for effective dose for various interventional radiology procedures. Med Phys May;39(5): doi: / /30/2018 Fluoro DICOM is the Wild West Information missing or wrong NCRP 160 Typically care about Skin Dose Struelens L., Bacher K., Zankl M. (2009) Dose-Area-Product to What about O., Schlegel W.C. (eds) World Congress on Medical Physics and Effective Dose IFMBE Proceedings, vol 25/3. Springer, Berlin, Heidelberg paediatric DAP interventional and cardiology. Br J Radiol Aug;82(981): Conversion Factors Effective Dose in Interventional Cardiology and Radiology. In: Dössel Biomedical Engineering, September 7-12, 2009, Munich, Germany. KARAMBATSAKIDOU A, et al. Effective dose conversion factors in Schmidt PWE et al. Conversion factors for the estimation of effective dose in paediatric cardiac angiography. Physics in Medicine & Biology, Vol45(10). 18 6

7 E = C*DAP E = 0.15*9.37 Gy*cm 2 E = 1.41 mgy 19 > 5 Gy Follow up Done? Sure Stecker MS, Balter S, Towbin RB, et al. Guidelines for patient radiation dose management. J Vasc interv Radiol 2009; 20:S263-S > 5 Gy Follow up < 5 Gy Maybe not 21 7

8 Backscatter Backscatter from patient Air Kerma Patient position relative to IRP Display vs. Measured Attenuation/Forward Scatter Table and pad Air to Tissue Conversion Geometry 22 IRP 15 cm from iso towards tube... most of the time 30 cm thick and set at isocenter 23 Correct for real skin position Inverse square Where is the skin position? Table position 24 8

9 0.6 to 0.8 CF Measured? Forward Scatter Vijayan, S., Xiong, Z., Guo, C., Troville, J., Islam, N., Rudin, S., & Bednarek, D. R. (2018). Calculation of Forward Scatter Dose Distribution at the skin entrance from the patient table for fluoroscopically guided interventions using a pencil beam convolution kernel. Proceedings of SPIE--the International Society for Optical Engineering, 10573,

10 How much? 1.3 to 1.4 HVL & Energy Measure? Benmakhlouf H et al. Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry. Phys Med Biol Nov 21;56(22): Andreo, Pedro. (2015) Benmakhlouf Fransson Andreo_BSF & mu_en diag radiol dosimetry_report KS-ASF IR /RG We have seen 10% - 20% Have heard of much worse Report No Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190 Medical Physics, Vol 42, Issue 12 (2015) 29 Tissue Dose Not Air Jones AK and Pasciak AS. Calculating the peak skin dose resulting from fluoroscopically guided interventions. Part I: Methods. JACR 2011; 12(4):

11 Put a phantom on the table with a dosimeter and see what you get for similar settings and number of images. Fill in unknowns with typical for a procedure type 31 Group similar angles together and use cumulative values if calculating by hand 32 Wedges and compensation filters are likely not accounted for Lateral and longitudinal patient table motion not accounted for Patient motion not accounted for Heal effect not accounted for 33 11

12 Error bars exist on every measurement Reports likely should include uncertainty How long? 6 mo... Maybe Dose tracking programs... If you can get them working 36 12

13 CFR 803 Report serious injury from a device Unless it is unlikely to happen again 39 13

14 40 Maintain records of Fluoroscopic (3701: (B)(4)) Patient Dose 41 Fluoroscopic ( (m)(9)(D)) Patient Dose 42 14

15 43 44 Tag Description (0018, 0060) kvp (0018, 1110) Source-to-Detector Distance (0018, 1111) Source-to-Isocenter Distance (0018, 1114) Magnification Factor (0018, 1149) Field of View Dimensions (0018, 1150) Exposure time (0018, 1151) X-Ray Tube Current (0018, 1152) Exposure (0018, 1155) Radiation Setting (0018, 1162) Intensifier Size (0018, ) Collimator Size and Positions (0018, ) Primary & Secondary Angles Tag Description (0018, 115E and 9473) DAP (0028, 0008) Number of Frames (0018, 5101) View Position (0018, 9406) Table Position Macro (0018, 7060) Exposure Control Mode (0018, 1162) Intensifier Size (0018, ) (0018, ) Collimator Size and Positions Primary & Secondary Angles 45 15

16 Stecker MS, Balter S, Towbin RB, et al. Guidelines for patient radiation dose management. J Vasc interv Radiol 2009; 20:S263- S273. Miller DL, Balter S, Cole PE, et al. Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study Part I: Overall Measures of Dose. J Vasc Interv Radiol 2003; 14: Miller DL, Balter S, Cole PE, et al. Radiation Doses in Interventional Radiology Procedures: The RAD-IR Study Part II: Skin Dose. J Vasc Interv Radiol 2003; 14: Jones AK and Pasciak AS. Calculating the peak skin dose resulting from sluoroscopically guided interventions. Part I: Methods. JACR 2011; 12(4): Jones AK and Pasciak AS. Calculating the peak skin dose resulting from sluoroscopically guided interventions. Part II: Methods. JACR 2011; 13(1): Sensakovic, WF. MO-K-207-3: Fluoroscopy Dose Calculations. 60 th Annual Meeting of the AAPM, Nashville, TN July 29-August 2, NASA Earth Observatory (Public Domain) Thank You! 16

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