Outpatient 131I-rituximab radioimmunotherapy for non-Hodgkin lymphoma: a study in safety

Abstract

Purpose: This study aimed to establish the safety of outpatient 131I-rituximab radioimmunotherapy by measuring the radiation exposure of hospital staff, carers, and members of the public and by estimating the environmental impact of radioactive urinary excretion.

Methods: Two hundred consecutive outpatients treated with 131I-rituximab radioimmunotherapy of non-Hodgkin lymphoma (NHL) with therapeutic activities between 1 and 4.5 GBq (mean, 2.3 GBq; or between 27 and 121 mCi; mean, 62 mCi) predicated on a prescribed whole-body radiation-absorbed dose of 0.75 Gy were studied. Their 279 family members/carers and 432 visitors wore thermoluminescent dosimeter badges for the week during which the patients were confined to their home after treatment.

Results: All 200 patients received 131I-rituximab activities according to the prescribed dose of 0.75 Gy to the whole body. From 200 consecutive patients, over the 7 days after therapy, mean radiation exposure of adult carers was 0.49 mSv (range, <0.01 to 3.67 mSv). To other coresiding family members, mean exposure was 0.23 mSv (range, <0.01 to 1.20 mSv), and for visitors sharing badges, the mean exposure was 0.17 mSv (range, <0.01 to 0.73 mSv). Urinary activity excreted over the week after 131I-rituximab therapy was typically less than 25% of the administered activity.

Conclusions: 131I-rituximab radioimmunotherapy for non-Hodgkin lymphoma may be safely administered on an outpatient basis. The median radiation exposure of carers, cohabitants of the patient, and visitors is well within the limits recommended by international guidelines. Local regulatory agency-designated patient release rate limit of less than 25 μSv/h at 1 m was attained within 1 week of therapeutic 131I-rituximab administration.