Implantação de programas de monitoração da exposição ocupacional interna em serviços de medicina nuclear no Brasil: situação atual e perspectivas futuras no escopo do projeto IAEA RLA 9075

In Brazil about 33 million procedures of diagnostic and therapy in nuclear medicine are carried out annually. 131I is used in about 350 clinics over the country and should by highlighted among other radionuclides because of the risk of occupational internal exposure. The elemental iodine is volatile and can be inhaled as a free gas or as a particulate in suspension in the workplace. According to the biokinetic model suggested by the ICRP, when iodine vapor is inhaled, it is transferred by diffusion from pulmonary-alveolar region directly to the blood stream and, subsequently, about 30% are absorbed by the thyroid gland. Although most of the workers who handle radionuclides in medical facilities are monitored routinely to the control of external exposure to radiation, in relation to internal exposure, and despite the existence of clear international recommendations and national regulations, few workers have been monitored in a regular basis in Latin America. Thus, a working group of experts on internal dosimetry has been established in the scope of the IAEA Regional Project RLA9075, with the main objective of disseminating the methodologies of monitoring and internal dose estimation among nuclear medicine professionals. The implementation of the internal monitoring procedures should be conducted by a professional of the clinic under supervision of the working group at the national level. Such strategy aims to disseminate internal monitoring plans so that a higher number of occupationally exposed workers should be controlled and the risks of intakes are reduced to acceptable levels in nuclear medicine services.