Comparison of three cold kit reconstitution techniques for the reduction of hand radiation dose

In the performance of conventional nuclear pharmacy work, personnel usually receive the highest hand radiation dose during reconstitution of Tc-99(m)- labelled radiopharmaceuticals. This study was conducted to compare the hand radiation doses incurred during the preparation of Tc-99(m)-labelled radio pharmaceuticals using three different reconstitution procedures: (1) the st andard reconstitution method (i.e. withdrawing Tc-99(m) activity and normal saline [NS] into the same syringe before adding to the cold kit) (standard ); (2) an alternative reconstitution procedure using two syringes to add no rmal saline separately before Tc-99(m) activity to the cold kit (NS/Tc); an d (3) a standard reconstitution procedure using a robotic system (Amercare Syringe Fill Station, model NuMed SFS 3a, Amercare Ltd, Oxon, UK) (robot). Radiation doses were monitored by thermoluminescent dosimeters (Landauer In c., Glenwood, IL, USA) on the base of the fourth finger (i.e. ring finger) of the non-dominant hand and on the mid-portion of the second finger (i.e. index finger) of the dominant hand. Three sets of ring badges were measured for each procedure, with 10 simulated or real reconstitutions per set. Two different radiopharmaceutical kits were evaluated: Tc-99(m)-MDP, as it is the most frequently used radiopharmaceutical in the majority of nuclear med icine departments (all three reconstitution methods; i.e. standard, NS/Tc a nd robot), and Tc-99(m)-sestamibi, as it is not only reconstituted with the highest amount of radioactivity but is also the most frequently dispensed radiopharmaceutical in our laboratory (standard and robot). All kits were p repared from an elution vial containing a standardized amount of Tc-99(m) a ctivity (i.e. 104.4 +/- 3.6 GBq). To each of the cold MDP and sestamibi kit s, 20.7 +/- 1.2 GBq and 44.2 +/- 0.7 GBq of Tc-99(m) activity were added, r espectively. Average accumulated radiation doses for 10 reconstitutions to the fingers (non-dominant/dominant) for the preparations of Tc-99(m)-MDP we re as follows: 14.2 +/- 0.9 mSv/2.8 +/- 0.8 mSv (standard), 10.0 +/- 0.6 mS v/ 2.7 +/- 0.2 mSv (NS/Tc), and 0.6 +/- 0.1 mSv/1.3 +/- 0.1 mSv (robot). Fo r Tc-99(m)-sestamibi, the average accumulated radiation doses for 10 recons titutions to the fingers (non-dominant/dominant) were 6.7 +/- 0.7 mSv/4.6 /- 0.5 mSv (standard) and 1.1 +/- 0.1 mSv/3.1 +/- 0.4 mSv (robot). When com pared to the standard reconstitution method, our results show that the NS/T c method slightly reduced radiation dose to the non-dominant hand, without any significant reduction for the dominant hand. However, the robot has pro ved to be the most effective method to considerably reduce radiation dose t o both hands. A robotic system should be a useful ALARA (as low as reasonab ly achievable) tool to prepare other high-activity Tc-99(m)-labelled radiop harmaceuticals, as well as therapeutic and PET radiopharmaceuticals. ((C) 1 999 Lippincott Williams & Wilkins).