Example of Practice of Radiation Protection

1. Example of Practice of Radiation Protection L 9.2

2. Educational Objectives • How awareness of radiation protection and close cooperation with medical physics / radiation safety staff helps • Avoidance of skin injuries Lecture 9.2: Example of practice of radiation protection

3. Introduction • The evaluation of maximum local skin dose from an interventional procedureis 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. Lecture 9.2: Example of practice of radiation protection

4. 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 Lecture 9.2: Example of practice of radiation protection

5. Patient database: CA and PTCA in Udine hospital from 1998 to 2002 Lecture 9.2: Example of practice of radiation protection

6. CA and diagnostic procedures DAP distribution of CA procedures Lecture 9.2: Example of practice of radiation protection

7. PTCA procedures DAP distribution of PTCA procedures Lecture 9.2: Example of practice of radiation protection

8. Frequencies of repeated procedures and cumulative dose Lecture 9.2: Example of practice of radiation protection

9. Sample of patients extracted for the follow-up study 79 patients with a cumulative DAP>300 Gycm2 extracted from the database Distribution of number of procedures performed and cumulative DAP Lecture 9.2: Example of practice of radiation protection

10. Sample of patients extracted for the follow-up study Maximum local skin dose evaluated for the 79 patients Lecture 9.2: Example of practice of radiation protection

11. 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  MSD= 0.0141*DAP Lecture 9.2: Example of practice of radiation protection

12. Skin dose assessment (patient no. 1) • Patient no. 1: Total maximum local skin dose6,7 Gy Lecture 9.2: Example of practice of radiation protection

13. 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 Lecture 9.2: Example of practice of radiation protection