Extremity doses assessment of nuclear medicine staff involved in 99mTc-radiopharmaceuticals preparation: A multicentre study

Introduction the skin of the hands of the nuclear medicine’s staff involved in preparation and manipulation of unsealed radiopharmaceuticals is the organ at highest risk for irradiation. The dose limit, to be applied to the average of 1 cm 2 of skin regardless the surface of the exposed area, is of difficult assessment. The ORAMED project identified the tip of the index of the non-dominant hand as the point of maximum exposure. Due to the high estimated proportion of workers liable to exceed the extremities annual dose limit (15–20%), the fingers dose monitoring is highly recommended especially in busy labs. Purpose To evaluate under routine operating conditions, in 3 nuclear medicine departments, the irradiation dose to the extremities of workers involved in the preparation of 99m Tc-radiopharmaceuticals. Materials and methods Two operators for each centre were monitored by using 4 TLD (LiF: Mg, Cu, P) for 2 weeks. For each single task the operational time and the manipulated activities were recorded. Results The mean daily 99m Tc activity manipulated was 56 GBq resulting in a mean dose equivalent values of: 38.5, 18.9, 5.4 and 63.7 microSv/GBq for the monitored hand positions: index tip of non-dominant, index base of non-dominant, wrist of non-dominant and index tip of dominant hand respectively. Conclusion Conversely to the ORAMED findings, the index fingertip of the dominant hand receives the highest dose. Based on the daily handled activities, the dose limit could be exceeded in 138 working days, thus confirming the concerns raised by many authors.