Reductions in finger doses for radiopharmaceutical dispensing afforded by a syringe shield and an automatic dose dispenser.

A gamma extremity monitoring system (GEMS) has been used to measure finger doses during radio-nuclide dispensing procedures. GEMS uses a small semi-conductor probe that can be attached to a finger from which a continuous read-out can be obtained that is related to dose rate. The pattern of dose accumulation can be analysed to allow doses received from individual operations within a procedure to be evaluated. GEMS has been used to compare the radiation dose reduction afforded by a syringe shield and an automatic dose dispenser. Dispensing procedures were simulated using 10% of the activity normally administered in order to avoid problems with detector saturation. Results show that the syringe shield and the automatic dose dispenser reduced finger doses by more than a factor of 10 for the procedures tested. The disadvantages of the automatic dispenser tested were a failure to transfer activity in 10% of cases and a longer time taken for the dispensing process. GEMS has the potential to facilitate greater optimization of finger doses through analysis of finger dose patterns.