Intercomparison of Extremity Dosimeters in Beta, Photon and Medical Realistic Fields Performance of ring dosimeters in typical medical fields

摘要

The EURADOS Working Group 9 is presently coordinating research activities on the assessment ofoccupational exposures at workplaces in therapeutic and diagnostic radiology as well as in nuclear medicine. Arecent literature review showed that extremity doses, especially in nuclear medicine and interventional radiology,can be quite high. However, the use of extremity dosimeters in hospitals is still not very common. Furthermore,there is very little information on the performance of these dosimeters in typical medical fields. Within thisframework, EURADOS organized an intercomparison of ring dosimeters aimed at assessing the technicalcapabilities of available extremity dosimeters and focusing on their performance at workplaces with potentiallyhigh extremity doses. 24 services from 16 European countries participated in the intercomparison. The dosimetersrepresented in this study are used to monitor over 30,000 workers. The dosimeters were exposed to referencephoton (~(137) Cs) and beta (~(147) Pm, ~(85)Kr and ~(90)Sr/~(90)Y) fields as well as to realistic interventional radiology (direct andscattered radiation) and nuclear medicine fields (~(99m)Tc and ~(18)F). This report presents the main results of theintercomparison. It is shown that most dosimeters provided satisfactory measurements of Hp(0.07) for photonradiation, both in reference and realistic fields. However, only four dosimeters fulfilled the requirements given bythe trumpet curves for all tested radiation qualities. The main difficulties were found for the measurement of lowenergy beta radiation. A clear correlation between filter and detector thickness and response to beta particles wasfound, thus highlighting the need for appropriate dosimeter design for these fields. Finally, the results also showeda general under-response of detectors to ~(18)F, which was attributed to the difficulties of the dosimetric systems tomeasure the positron contribution to the dose.