Radiation protection of medical staff: a coordinated action by EURADOS on extremely dosimetry and the use of active personnel dosemeters (CONRAD)

Monitoring of workers constitutes an integral part of any radiological protection program. However, unresolved issues in radiation protection of medical staff still remain. Research and establishment of guidelines are necessary on a variety of issues such as extremity dosimetry (fingers, eye lenses, etc), the use of double dosimetry above and below lead aprons, or the use of electronic personal dosimeters in interventional procedures. Medical practices are also evolving fast, and new techniques with ionising radiation emerge very regularly, thus implying the need of radiation protection measures for medical staff, and the implementation of new monitoring programs. In some medical applications of radiation there is an increased risk of high local exposures because of direct handling of sources or the use of beta-emitters. However, despite the large number of workers that are exposed in the medical field worldwide, only few measurements of extremity doses have been reported in the literature. Some activities of EURADOS Working Group 9 (WG9) were sponsored by the European Commission in the CONRAD project. This CONRAD project was aiming at the coordination of research on radiation protection at the workplace. Working group 9 has been involved in the coordination and promotion of European research in the field of Radiation Protection Dosimetry for Medical Staff. One of the objectives of this working group was to formulate the state of the art and to identify areas in which improvements were needed. For some of these medical applications the skin of the fingers is the limiting organ from the point of view of individual monitoring of external radiation. The wide variety of radiation field characteristics in a medical environment, and the difficulty of measuring a local dose that is representative for the maximum skin dose (usually with one single detector), makes it difficult to perform extremity dosimetry with an accuracy similar to whole-body dosimetry. Therefore a subgroup of WG9 dealt specifically with the use of extremity dosemeters in medical radiation fields. Active personal dosimeters (APDs) are very efficient tools to monitor occupational doses in real time during exposure and provide selectable alarm levels to avoid high doses. Interventional radiology operators belong to a specific worker category, which would benefit from a real time, accurate assessment of their dose. Another subgroup dealt with the adequate dosimetry of scattered photons, using APDs. They must be able to respond to low-energy (10-100 keV) and pulsed radiation with relatively high instantaneous dose rates