Returning to work after I-131 treatment: A Nuclear Medicine Technologist’s Personal Experience

Objectives: Radiation safety guidelines for the release of patients receiving radioactive iodine (RAI) treatment are well established. However, these guidelines are rarely tailored to the specific occupation of the patient. When the patient is a Nuclear Medicine Technologist (NMT), the limitations experienced in daily job duties can be quite apparent. This is an NMT’s perspective on receiving radioactive iodine treatment, and the limitations encountered upon returning to work post treatment. Methods: An NMT was treated for Graves’ Disease (70% thyroid uptake at 24 hours) with 20mCi I-131 Sodium Iodide. The NMT was permitted to return to work 3 days post administration by the treatment facility (after consultation with the medical physicist/Radiation Safety Officer and treating physician). Over the subsequent months, the NMT experienced numerous job specific limitations which would not typically be encountered by non-radiological workers. Limitations were observed and documented by the NMT and NMT supervisor. Exposure measurements were also measured periodically post treatment. Results: The NMT and supervisor analyzed the NMT’s daily work duties, and produced a list of limitations. Due to substantial radiation being emitted from the NMT, she could not wear dosimetry badges (body or ring), perform any I-123 uptake measurements, administer I-131 (until bioassay at background), perform surveys using a Geiger-Mueller survey meter (including area monitoring or package receipt), perform normal call duties, nor perform daily calibration/constancy quality control on the well counter or uptake probe. Other job duties could be performed, but with caution. The NMT was careful to not position her body too close to the camera detectors when performing flow studies of any kind, as the count rate on either detector of the camera was up to 21.4 kcts/sec above background, with the NMT standing directly next to the detectors, during the first week after dose administration. The importance of this became apparent during a bone flow study of the feet, where the NMT instinctively positioned herself next to the feet after the patient began moving, causing a “shine” scintillation artifact (figure 1). The NMT could perform wipes but had to step at least 3 meters away from the well counter before the wipe began. Also, the NMT could assay doses if standing at least 1 meter from the dose calibrator (at 5 days, background was 25uCi on Tc-99m channel, with NMT less than 1 meter from aperture of dose calibrator). All other job duties could be done without limitations. Measurements of the NMT with an ionization chamber immediately after dose administration were 41mR/hr at the surface and 3mR/hr at 1 meter from the abdomen. One-month post-administration, those measurements were 6.0 mR/hr and 0.08 mR/hr, respectively. Due to these measurements, 1 month post RAI, the NMT had not resumed all normal job duties. Once measurements are at background, the NMT will resume all normal job duties. Possible increases in other staff members’ dosimetry readings were considered, and will be analyzed once the occupational radiation exposure report is available. Conclusions: The general public does not typically have limitations in work duties once cleared for work post RAI by the treating facility. NMTs are not the general public (as defined by the Nuclear Regulatory Commission). Therefore, it is important to note that as an NMT receiving radioactive treatment of any kind, in this case RAI, limitations in job duties must be planned for. This is especially important in single NMT departments or pediatric nuclear medicine facilities, where a “fill in” NMT or substantial scheduling adjustments may be necessary.

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