Optimization of a Labeling and Kit Preparation Method for Ga-68 Labeled DOTATATE, Using Cation Exchange Resin Purified Ga-68 Eluates Obtained from a Tin Dioxide 68Ge/68Ga Generator.

ABSTRACT

PURPOSE: The aim of this study was to optimize a radiolabeling method using cationic processed Ga-68 eluates from a SnO2-based 68Ge/68Ga generator, followed by the development of DOTA-Tyr3-Thre8-octreotide (DOTATATE) kits. PROCEDURES Diluted generator eluates were adsorbed on a SCX resin and desorbed with acidified 5 M NaCl solution. Optimized labeling conditions were determined by variation of pH, using 35 µg DOTATATE and sodium acetate buffer. DOTATATE kits were developed based on optimized radiolabeling conditions, were labeled, and evaluated. RESULTS: Optimized labeling conditions resulted in a radiolabeling efficiency of around 99 % and radiochemical yield of almost 85 %. Different kit preparation methods did not significantly influence the radiolabeling results. Kits were found to be stable over 3 months. CONCLUSION: A labeling method using SCX-processed Ga-68 eluates was optimized. DOTATATE kits specifically for these SCX-processed Ga-68 eluates were successfully formulated. A post-labeling Sep-Pak C18 purification should be optional.