IAEA Training Material on Radiation Protection in Cardiology

International Atomic Energy Agency Example of Practice of Radiation Protection L 9.2 Educational Objectives 1. How awareness of radiation protection and close cooperation with medical physics / radiation safety staff helps 2. Avoidance of skin injuries Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 2 Introduction The evaluation of maximum local skin dose from an interventional procedure is difficult: On-line evaluation: dosemeter or computer code Off-line methods more accurate: use of large area detectors, time consuming (adopted for a limited number of patients) It should be important to periodically evaluate incidence of skin injuries in cardiac centres A follow-up protocol has been developed in Dimond European research project (www.dimond3.org): Purpose to identify patients with an high probability of an

high localised skin dose to be submitted to a follow-up. The protocol adopts a trigger value in terms of dose-area product (DAP) as a dose quantity indicator of possible localised high skin dose. Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 3 Retrospective evaluation of skin injuries on patients of Udine cardiac centre Patient can be submitted to repeated cardiac procedures in short period of time Methodology: Analyse database of patients submitted to diagnostic and therapeutic procedures in a 4 years period Detect patients with highest cumulative DAPs (due to repeated procedures) selecting an appropriate DAP trigger value Evaluate maximum local skin dose Submit selected patients to a clinical evaluation to detect possible skin injuries Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 4 Patient database: CA and PTCA in Udine

hospital from 1998 to 2002 SAMPLE COLLECTION 21 April 1998 - 17 April 2002 NUMBER OF PROCEDURES 5517 N. OF PTCA PROCEDURES 1843 N. OF CA PROCEDURES 3674 N. OF PATIENTS 3332 Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 5 CA and diagnostic procedures 500 3674 Mean DAP 37.5 Gycm2 Median DAP No. of procedures with DAP>300Gycm2

31.2 Gycm2 1 400 Frequency No. of procedures 300 200 100 0 0 50 100 150 200 250 Gy cm^2 DAP distribution of CA procedures Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 6 300 No. of procedures 1843

Mean DAP 66.1 Gycm2 Median DAP 48.3 Gycm2 No. procedures with DAP>300Gycm2 13 (0.7%) Frequency PTCA procedures 160 140 120 100 80 60 40 20 0 0 50 100 150 200 250 300 350 400 450 500 Gy cm^2 DAP distribution of PTCA procedures Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 7

Frequencies of repeated procedures and cumulative dose No. of procedures per patient 1 2 3 4 5 6 7 >7 No. of patients 1967 940 194 138 41 29 14 9 600 500

3332 Mean DAP 78.6 Gycm2 Median DAP 50.6 Gycm2 No. of patients with DAP>300Gycm2 87 (2.6%) Frequency No. of patients 400 300 200 100 0 0 100 200 300 400 500 600 Gy cm^2

Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 8 700 Sample of patients extracted for the follow-up study 79 patients with a cumulative DAP>300 Gycm2 extracted from the database 18 16 14 12 10 8 6 4 2 0 40 35 30 No. of patients No. of patients Distribution of number of procedures performed and cumulative DAP 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Number of procedures/patient

Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection DAPtotal (Gycm2) 9 Sample of patients extracted for the follow-up study No. of patients Maximum local skin dose evaluated for the 79 patients 18 16 14 12 10 8 6 4 2 0 1.5 Radiation Protection in Cardiology 2 2.5 3 3.5 4 4.5 5 5.5 6 Maximum Local Skin Dose (Gy) Lecture 9.2: Example of practice of radiation protection 6.5 7 10

Maximum local skin dose (MSD) assessment Correlation between DAP and MSD has been evaluated: operator and installation dependent Skin dose distributions measured on a sample of patients with radiochromic films Maximum local skin dose versus DAPfor PTCA MSD= 0.0141*DAP 4.0 PSD= 0.0141*DAP PSD(Gy) 3.0 2.0 1.0 0.0 0 Radiation Protection in Cardiology 50 Lecture 9.2: Example of practice of radiation protection 100 150 DAP (Gycm2) 200 11 250 Skin dose assessment (patient no. 1) Patient no. 1: Total maximum local skin dose 6,7 Gy Procedure type

DAP per procedure(Gycm2) Maximum local skin dose (Gy) Diagnostic 86.9 0,416 Diagnostic 86.3 0,413 Diagnostic 26.8 0,128 Ad hoc PTCA 57.1 0,509 Diagnostic 108.6 0,520 Diagnostic 73.8 0,354

135.6 1,208 Diagnostic 28.4 0,136 Ad hoc PTCA 33.8 0,301 Election PTCA 84.7 0,755 Diagnostic 58.4 0,280 115.3 1,027 Diagnostic 27.2 0,130 Diagnostic 33.5

Ad hoc PTCA 39.2 Ad hoc PTCA Ad hoc PTCA Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 12 Conclusions 56 patients received medical examination with particular focus on the more exposed skin area. None of visited patients presented skin lesions that could be attributed to high dose X-ray irradiation The result assures cardiologists and medical physicists that, if proper quality assurance and radiation protection programme is established, the frequency of skin injuries can be very low also when repeated procedures are taken into account Radiation Protection in Cardiology Lecture 9.2: Example of practice of radiation protection 13