Dose measurement received by the exposed occupationally personnel of the nuclear medicine department of the INCan

Personal dose equivalent (PDE) values were determined for occupational exposed workers (OEW) at the Nuclear Medicine Department (NMD) of Instituto Nacional de Cancerologia (INCan), Mexico, using TLD-100 thermoluminescent dosemeters. OEW at NMD, INCan make use of radiopharmaceuticals for diagnosis and treatment of diseases. Radionuclides associated to a pharmaceutical compound used at this Department are 131I, 18F, 67Ga, 99mTc, 111In and 201Tl with main gamma emission energies between 93 and 511 keV. Dosemeter calibration was performed at the metrology department of Instituto Nacional de Investigaciones Nucleares, Mexico. Every occupational worker used dark containers with three dosemeters which were replaced monthly for a total of 5 periods. Additionally, control dosemeters were also placed at a site free of radioactive sources in order to determine the background radiation. Results were adjusted to find PDE/day and estimating annual PDE values in the range between 2 mSv (background) and a maximum of 9 mSv. Two of the 16 members of the OEW receive high estimated annual doses (6-9 mSv), other 5 receive annual doses between 3 and 5 mSv, other 3 between 2.5 and 3 mSv, and the rest receive dose values consistent with background radiation. These values are dependent on their daily activities and it is clear that the maximum doses are received by those OEW who perform nursing duties and receive radiopharmaceuticals for daily use. All obtained values are well within the established annual OEW dose limit stated in the General Regulation of Radiological Protection, Mexico (50 mSv) as well as within the lower limit recommended by the International Commission on Radiation Protection, report no. 60 (20 mSv). Additionally, consistence was found between measured monthly values and those reported by the firm that performs the monthly service. These results verify the adequate compliance of the NMD at INCan, Mexico with the standards given by the national regulatory commission. (Author)