PURPOSE: To assess the radiation exposure to individuals coming from patients after treatment with holmium-166 ((166)Ho) microspheres. MATERIALS AND METHODS: Holmium-166 radioembolization (RE) with escalating whole-liver doses of 20 Gy, 40 Gy, 60 Gy, and 80 Gy was administered to 15 patients. Exposure rates (μSv/h) from patients were measured at 1.0 m distance from a lateral and frontal position at 0, 3, 6, 24, and 48 hours after infusion. The total effective dose equivalent (TEDE) to a maximally exposed contact was calculated in accordance with guidelines of the U.S. Nuclear Regulatory Commission (NRC). Results were extrapolated to a whole-liver dose of 60 Gy used in future treatments. RESULTS: The median exposure rate at discharge, 48 hours after infusion, measured from a lateral position was 26 μSv/h (range, 7-45 μSv/h). Extrapolated to a whole-liver dose of 60 Gy, none of the exposure rates for the NRC contact scenario, at any time, frontal or lateral, would lead to a TEDE > 5 mSv; all patients may be released directly after treatment. Release after 6 hours is possible without contact restrictions for patients who received up to 7 GBq. CONCLUSIONS: The TEDE to a contact of patients treated with (166)Ho RE would not exceed the NRC limit of 5 mSv. Contact restrictions 6 hours after treatment are unnecessary for infused activities < 7 GBq.
PURPOSE: To assess the radiation exposure to individuals coming from patients after treatment with holmium-166 ((166)Ho) microspheres. MATERIALS AND METHODS:Holmium-166 radioembolization (RE) with escalating whole-liver doses of 20 Gy, 40 Gy, 60 Gy, and 80 Gy was administered to 15 patients. Exposure rates (μSv/h) from patients were measured at 1.0 m distance from a lateral and frontal position at 0, 3, 6, 24, and 48 hours after infusion. The total effective dose equivalent (TEDE) to a maximally exposed contact was calculated in accordance with guidelines of the U.S. Nuclear Regulatory Commission (NRC). Results were extrapolated to a whole-liver dose of 60 Gy used in future treatments. RESULTS: The median exposure rate at discharge, 48 hours after infusion, measured from a lateral position was 26 μSv/h (range, 7-45 μSv/h). Extrapolated to a whole-liver dose of 60 Gy, none of the exposure rates for the NRC contact scenario, at any time, frontal or lateral, would lead to a TEDE > 5 mSv; all patients may be released directly after treatment. Release after 6 hours is possible without contact restrictions for patients who received up to 7GBq. CONCLUSIONS: The TEDE to a contact of patients treated with (166)Ho RE would not exceed the NRC limit of 5 mSv. Contact restrictions 6 hours after treatment are unnecessary for infused activities < 7 GBq.
Authors: M Weber; M Lam; C Chiesa; M Konijnenberg; M Cremonesi; P Flamen; S Gnesin; L Bodei; T Kracmerova; M Luster; E Garin; K Herrmann Journal: Eur J Nucl Med Mol Imaging Date: 2022-02-11 Impact factor: 9.236