Occupational exposure of radiation workers, including nurses, is an important issue that should always be considered. However, there are limited reports on external exposure of nurses working in nuclear medicine investigated using a personal dosimeter with a trend function. We investigated the relationship between the personal dose equivalent and behavior of nurses in nuclear medicine using a personal dosimeter with a trend function. It was found that the external exposure of nurses was high when they cleaned hospital rooms where patients who received radiopharmaceutical drugs were admitted. However, none of the nurses surveyed exceeded 3μ. Visualization of the contamination in the hospital room showed that the area around the sink and trash can was particularly contaminated. Hence, nurses need to be more careful when cleaning. Although it is unlikely that the nurses surveyed will be affected by external exposure, data in this report is valuable for nurses at medical institutions to consider work hours and personnel strategies.

Radiopharmaceuticals with high radioactivity are used in the field of nuclear medicine. Moreover, understanding the exposure dose of radiation workers and the air dose in radioisotope preparation rooms is essential. In particular, evaluating exposure dose assuming an accident to reduce radiation exposure as much as possible and respond to the accident is paramount. Thus, we evaluated a case study where 1.34 GBq 99Mo-99mTc generator used in our hospital fell, and evaluated exposure doses. The results of the considered drop accident of a commercially available generator indicated a possibility of radiation exposure equivalent to several months of normal work exposure, even though the possibility of radiation exposure to the extent that deterministic biological effects appear is low. Therefore, more attention must be paid to managing radiopharmaceuticals with high radioactivity, such as generators, to reduce the anxiety of radiation workers in the hospital and respond rapidly to accidents. Furthermore, the study findings should be used for staff training during normal times to avoid unnecessary radiation exposure.