Outpatient treatment with I-131-anti-B1 antibody: Radiation exposure to family members

The Nuclear Regulatory Commission (NRC) regulations that govern release of patients administered radioactive material have been revised to include dos e-based criteria in addition to the conventional activity-based criteria. A licensee may now release a patient if the total effective dose equivalent to another individual from exposure to the released patient is not likely t o exceed 5 mSv (500 mrem). The result of this dose-based release limit is t hat now many patients given therapeutic amounts of radioactive material no longer require hospitalization. This article presents measured dose data fa r 26 family members exposed to 22 patients treated for non-Hodgkin's lympho ma with I-131-anti-B1 antibody after their release according to the new NRC dose-based regulations. Methods: The patients received administered activi ties ranging from 0.94 to 4.77 GBq (25-129 mCi), Family members were provid ed with radiation monitoring devices (film badges, thermoluminescent or opt ically stimulated luminescent dosimeters, or electronic digital dosimeters) . Radiation safety personnel instructed the family members on the proper we aring and use of the devices. Instruction was also provided on actions reco mmended to maintain doses to potentially exposed individuals as low as is r easonably achievable. Results: Family members wore the dosimeters for 2-17 d, with the range of measured dose Values extending from 0.17 to 4.09 mSv ( 17-409 mrem). The average dose for infinite time based on dosimeter reading s was 32% of the predicted doses projected to be received by the family mem bers using the NRC method provided in regulatory guide 8.39. Conclusion: Th erapy with I-131-anti-B1 antibody can be conducted on an outpatient basis u sing the established recommended protocol. The patients can be released imm ediately with confidence that doses to other individuals will be below the 5-mSv (500 mrem) limit.