Absorbed doses of the taxi drivers in the vicinity of the patients that were injected for SPECT imaging: a Monte Carlo study

Nuclear medicine is a branch of medical science that uses radionuclides for diagnosing and treatment of diseases. In this paper, the dose of the different organs and annual effective dose of a taxi driver were calculated in a vicinity of a patient that was injected for the brain, kidney, and liver SPECT by using Monte Carlo method. Two MIRD phantoms were simulated as a driver and patient, including the simple body of a taxi in MCNPX2.4 code. The radioactivity distributions were obtained from ICRP reports and sources were defined according to them. The patients that have undergone the brain, kidney and liver SPECT with the injection of different activities of the 99mTC radioisotope were included in this study. The injected activities were 740 MBq, 185 MBq, and 333 MBq for the brain, kidney, and liver SPECT respectively. Annual effective doses were calculated for one 99mTC injected patient per working day with an assumption of 30 min ride duration. The maximum annual effective doses of the taxi driver were 2.31, 0.54, and 1.21 $$\upmu \mathrm{S}\mathrm{v}$$ in the vicinity of the patients that were injected for brain, kidney, and liver SPECT respectively. The maximum annual effective dose of the taxi driver is larger than the ICRP recommended data up to 2.3 times. We recommend that to reduce dose, the patient should sit in “position 2”, farthest back seat with respect to the driver, and the driver’s seat could have some shielding place around it.