Revised Nuclear Regulatory Commission regulations for release of patients administered radioactive materials: outpatient iodine-131 anti-B1 therapy.

The Nuclear Regulatory Commission regulations for the release of patients administered radioactive material have been revised to include dose-based or activity-based criteria.The revised 10 CFR 35.75 regulations and the formula that can be used to determine when an individual patient administered radioactivity is releasable are reviewed. The implications of these new regulations on patient release after 131I anti-B1 therapy for the treatment of non-Hodgkin's lymphoma are also discussed.A licensee may now release patients if the total effective dose equivalent to another individual from exposure to a released patient is <500 mrem. Compliance with this dose limit is demonstrated by licensees either by using a default table for activity or dose rate provided in Regulatory Guide 8.39 or by performing a patient-specific dose calculation. Licensees may also demonstrate compliance by basing patient release on the patient-specific measured dose rate at 1 m instead of administered activity. Data on more than 50 patients receiving 131I anti-B1 therapy, an investigational therapy for non-Hodgkin's lymphoma, indicate that all patients would have been releasable under the new regulations.The new regulations will permit 131I anti-B1 therapy to be conducted on an outpatient basis.