Radiation safety measures in diagnostic nuclear medicine, based on the potential radiation dose emitted by radioactive patients

Abstract

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.

Risk estimates for ionizing radiation

“…The methodological limitations of the external dosimetry of the study in question are related to the response times of the detector systems and the Geiger calibration curves for the different radioisotope energies. Despite the uncertainties, the results and conclusion of the Willegaignon et al (2) study do not change. Therefore, the relevance of their work lies in ensuring the safe use of radioisotopes for occupationally exposed individuals and individuals in the general population, in accordance with radiation safety guidelines (4,5) .…”

“…Despite the fact that the use of radiation has proven safe for medical purposes, health professionals still have many questions about the risks of exposure, especially those related to nuclear medicine patients. To answer those questions about radiological safety, Willegaignon et al ( 2 ) conducted a study, published in a recent issue of Radiologia Brasileira, on radiation safety measures in diagnostic nuclear medicine. Their simple yet robust methodology allowed the quantification of radiation exposure of patients injected with radioisotopes.…”

“…The Willegaignon et al ( 2 ) article allows us to conclude that the equivalent doses for individuals in the general population do not exceed the limit of 1 mSv/year established for such individuals ( 6 ) . In most cases, dose limits are incomprehensible to the public.…”

Theranostics and artificial intelligence: new frontiers in personalized medicine

“…Given that only trace amounts of radioactivity are used for diagnostic studies, the risks of radiation-induced damage to healthy tissue are often considered negligible 41 . However, for therapeutic purposes, radionuclides are also commonly administered in standardized dosages, like the administration of diagnostic purposes.…”

Predicting, Protecting, and Minimizing: A Software Tool for Safe Interactions with Nuclear Medicine Patients

“…Water phantoms serve to mimic patient bodily tissues, including the attenuation and self-absorption of radiopharmaceuticals. Investigations involving limited radiopharmaceuticals at fixed distances have been carried out with survey meters, conducted with water phantoms and nuclear medicine patients [8][9][10][11][12][13][14][15][16][17]. These studies consistently demonstrate that the cumulative dose and dose rates from nuclear medicine imaging patients are not of concern for those under occupational monitoring.…”