Results of extremity dosimetry based on the measurements at laboratory of individual and environmental dosimetry at IFJ PAN.

Laboratory of Individual and Environmental Dosimetry (LADIS) at the Institute of Nuclear Physics is the largest dosimetry service in Poland. Extremity ring dosimetry measurements are performed at LADIS laboratory for ˃20 years, with accredited procedure since 2002. According to the quality system based on PN-EN ISO/IEC 17025:2018-02 standard, Hp(0.07) personal dose equivalent is measured over the range of doses from 0.1 mSv to 1 Sv. Years of experience allow the laboratory to analyse the levels of doses received by workers in medical and industrial institutions cooperating with LADIS laboratory. Yearly, ˃30 000 of extremity measurements have been performed for about 1000 institutions in Poland on the quarterly basis. According to the internal classification, the radiation workers under radiation protection control have been divided into a few groups. The analysis indicated that most of the doses received by exposed workers were on the level of the natural radiation background, but some of them exceeded the dose limit. The results show that ˃60% of Hp(0.07) doses were below 0.1 mSv/quarter; however, some very high doses were also registered. The highest number of doses above 125 mSv was observed in nuclear medicine and interventional radiology. The percentage of overdoses was relatively small but looking at individual cases the risk of unexpected irradiation was noticeable. Therefore, constant monitoring is always necessary.