Assessment of radiation dose in nuclear medicine hot lab

Hot lab is a specially designed room in a nuclear medicine hospital where the radiopharmaceuticals are delivered, stored and prepared for dispensing. 99Mo/99mTc-generator is the major source in the hot lab used for various medical imaging. It is important to maintain a standard for hot lab procedures to optimize the patient care and minimize radiation exposure to all nuclear medicine personnel, patients, public, as well as environment. The radiation doses in the hot lab were measured by GM and NaI Detectors for about 12 months. Package surface doses and generator surface doses were also measured. An increase in the counted rate above background was considered for the study. A constant distance was made in every step. At the receipt date, the 99Mo/99mTc-generator surface dose (450±150 μGy/hr) found to be nearly six times higher than the package surface dose (80±20 μGy/hr). The dose rate at the outer surface of the fume-hood glass found to be 80±15 μGy/hr in the 1st day of generator placement, whereas at the 2nd day it was 70±12 μGy/hr; showing a gradual decline in dose rate during 3rd (50±10 μGy/hr), 4th (40±9 μGy/hr), 5th day (30±6 μGy/hr) and 6th day (25±4 μGy/hr). In the 1st day of a generator storing in the hot lab, the dose rate found to be 3-4 times higher than the 6th days. The dose rate at various places indicated poor performance of the fume-hood glass. The study emphasizes on the need of growing awareness among all the radiation workers and encouraging the safe working practices in nuclear medicine.