Radiation safety in nuclear medicine laboratories in India

Full text: In nuclear medicine (NM) centres, where unsealed and short-lived radionuclides are handled in GBq quantity for diagnostic and therapeutic purposes, the radiation safety is ensured by carrying out safety assessment of the procedure, protection surveys and monitoring of occupational personnel as well as the work place. The personnel are likely to receive external and internal exposures, while carrying out NM practices in the laboratory. Among 135 NM centres in India, there are about 95 active centres which have trained and qualified staff. As a result, the average yearly effective dose to occupational personnel engaged in various NM practices, is 0.73 mSv (1995). Only 0.24% of personnel monitored, receive the annual effective dose more than 10 mSv. The finger dose monitoring at such centres has indicated that the maximum exposure might be received while injecting the radiopharmaceuticals to patient. The hands may receive annual dose between 45-63 mSv. The other activities in NM, deliver less exposure to occupational personnel. Internal monitoring has shown thyroid burden of the order of 3.5 - 4.8 kBq in some cases. The family members, of the patients who had undergone thyrotoxicosis treatment, have been found to receive internal exposure in the range of 10-250 μSv and external exposure in the range of 50-300 μSv leading to total annual effective dose less than the dose limit for public i.e. 1 mSv. Only three cases of accidents in NM have been reported so far. There had been no case of excessive exposure in NM lab, except the one which occurred recently due to spillage of large activity of 131I