Accurate dose calibrator activity measurement of 90Y-ibritumomab tiuxetan

This investigation examined the accuracy of dose calibrator activity measurement of the beta-emitting radiopharmaceutical Y-90-ibritumomab tiuxetan. Methods: Five different facilities independently measured Y-90 in a 10-mL syringe geometry with 30 dose calibrator models from 3 different manufacturers. The activities ranged from 81.4 MBq (2.2 mCi) to 1,406 MBq (38 mCi) over the volume range of 3-9 mL. Results: The mean dial settings for Y-90 measurement were 375, 51 x 10, and 897 x 100 for Atomlab, CRC, and Mark V dose calibrators, respectively. The maximum volume dependence was 0.28%/mL. Conclusion: This study demonstrated that when measuring all volumes of Y-90-ibritumomab tiuxetan activity prescriptions, only a single dial setting for a given manufacturer's dose calibrator is required for accurate measurements. Volume corrections are not necessary. For best accuracy, an individually determined dial value should be used.