Optimised fractionation and most cost-effective use of expensive radiopharmaceuticals

Full text: Cardiolite and Ceretec are two very useful but costly 99mTc labelled radiopharmaceuticals. To improve cost-effectiveness, various fractionation techniques have been developed with normal saline, SnCI2 solution and stannous ion augmentation. The aim of this study was to simplify and test the best method of fractionation and assess cost savings in clinical use. Fractionation of Cardiolite kit with normal saline has the limitation that it can take only 2.5 GBq of 99mTc and the stannous augmentation method requires the preparation of fresh stannous solution for every use. Fractionation using nitrogen purged 50 pg/mL SnCI2 solution to 1:5 and stored at -20 degree C overcomes these limitations. They are ready to use vials and each vial can be reconstituted with 6.5 GBq of 99mTc. These fractionated kits were tested for a period of three months (n = 180) . The mean radiochemical purity was 92.1 + 2.7% and produced satisfactory clinical images. Cost savings were calculated as $40 000 per year if performing >3 patients per day and $56 000 per if <3 patients per day. Ceretec kit was fractionated to 1:5 using nitrogen purged normal saline and stored at -20 degree C. Subsequent stannous enhancement was done by the addition of 0.1 ml of Sn-PYP (18μg SnCI2) prior to reconstitution with 99mTc (1.3 GBq). Published methodology recommends preparation of fresh Sn-PYP solution for every use. To simplify this, we prepared and stored Sn-PYP in a 1 mL aliquot at 20 degree C for a period of one month. These kits (n = 33) produced acceptable clinical images and the mean radiochemical purity was 93.4%(range 86 - 98%). This yields an estimated saving of $22 000 per year in a department performing twice a week Ceretec studies. We conclude that fractionation of Cardiolite kit to 1:5 using SnCI2 solution and fractionation of Ceretec kit to 1:5 using normal saline and subsequent stannous enhancement prior to reconstitution are effective. In our view, these are the optimal techniques of fractionation for routine clinical use