Evaluation of manufacturer's recommended P-32 dial settings for a new dose calibrator

Objectives The objective of this research study was to evaluate and validate the manufacturer's P-32 dial value for the new Biodex Atomlab (A500) dose calibrator and to compare the results to the Biodex Atomlab (A100) dose calibrator.

Methods P-32 is a beta emitting radionuclide used in therapeutic procedures. A vial of P-32 Chromic Phosphate (CP) (17.4 mCi) was received and the vial activity was measured using 4 different Atomlab (A100) dose calibrators at the manufacturer's dial value of 632. The same vial was measured using 4 different Atomlab (A500) dose calibrators at the manufacturer's dial value of 530. A 1.0 ml aliquot of P-32 CP (5.19 mCi) was withdrawn and calibrated in a 3-ml syringe, measured in both dose calibrators at the same respective dial settings and compared to the manufacturer's specified activity. An appropriate dial value for P-32 CP vial was experimentally determined for the A500.

Results The mean calibrated activity readout for P-32 CP vial (15.74 mCi) in a A100 dose calibrator (632 dial value) and a A500 (530 dial value) was 14.86 mCi and 11.83 mCi, repectively, indicating a significant reduction in activity readout with the A500. The mean calibrated activity readout in the 1.0 ml P-32 syringe (5.19 mCi) in the A100 (632 dial value) and the A500 (530 dial value) was 6.40 mCi and 5.04 mCi, respectively, indicating a significantly higher readout for the A100. A new dial value of 712, corresponding to 17.4 mCi, was experimentally determined for P-32 CP vial using the A500.

Conclusions The P-32 dial setting for the A500 and A100 dose calibrators were evaluated. The A500 dial value (530) was appropriate for P-32 syringe activity and the A100 dial value (632) was appropriate for the P-32 vial activity. A new dial value (712) was established for the P-32 CP vial with the A500