Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures.

Patients undergoing Nuclear Medicine procedures, whether diagnostic or therapeutic, become radioactive sources for a period of time until the radioactive substance they incorporate is completely eliminated from their organisms. As a consequence, radioactive patients may expose other individuals and the environment to ionizing radiation. In order to reduce these exposures, radioprotective care with these patients is usually required. However, the small amount of radioactive material administered in diagnostic procedures leads to the question of the real need for such care and, even if this need is proven, it is still necessary to establish the period of its validity.There are no scientific studies in the literature to establish such care and its adequacy according to the clinical needs of each patient. Answers to these questions are linked to the true exposure potential these patients offer to other individuals, as well as the radiological risks arising from these exposures and radiation doses. Thus, this study primarily aims to evaluate these exposure potentials based on the study of patient-received radiopharmaceutical retention and excretion bikinetics, as well as to evaluate the radioprotective care to be implemented in diagnostic Nuclear Medicine either to reduce or control family exposures. and other individuals of the Society who may be exposed to these patients.