Enhanced delivery of F-18 activity from coincidence manifolds: A comparative study

Abstract

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Objectives: A common commercial automated FDG Synthesis unit is the Coincidence or TracerLab MX Synthesis box. These synthesis units utilize an automated synthesis process and for each synthesis a standard set of chemical reagents and a single use manifold are used. The objective of the study was to compare the manifolds from two different manufactures in their ability to transfer activity out of the reaction vessel into the purification cartridge. Methods: Two Coincidence Synthesis boxes were used for the study and were set up utilizing the standard set of chemical reagents. However, two different commercial manufacturers of manifolds were evaluated (A-Tech Int and Rotem Inc) on the synthesis units. F-18 was produced from a GE PETTrace cyclotron and after the synthesis units had been setup and the preliminary tests run the F-18 was delivered the automated synthesis process was started. To determine the efficiency of transfer out of the reaction vial the amount of activity which remained in the vial was read at the end of the labeling process and after the activity was transfered onto the tC-18 cartridge. Results: The results demonstrate that there was a significant difference in the amount of residual activity which remained in the reaction vial after the labeling process. The average (± sd)amount of activity which remained in the A-Tech manifold after transfer was 364 (± 141) mCi while in the Rotem manifold the average was 147 (± 67) mCi. The relative percentage of activity which was retained in the vial was based on the total amount of activity which was in the reactor vial at the end of synthesis and was found to be 7.68% for the A-Tech Manifold compared to 3.55% for the Rotem manifolds. [Table] Conclusions: Due to the slight differences in the components that exist between the different manufacturers the Rotem reaction vial demonstrated an increased efficiency of transfer out of the reaction vial. This increased transfer efficiency should result in an increased amount of F-18 FDG that is produced as well as an increase in the conversion yield of F-18 to F-18 FDG.