Abstract
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Objectives To evaluate the synthesis and quality control of generator based 68Ga-PSMA using an automated module
Methods 34 runs of the module were carried out over a period of 6 months. The eluate from a five months old 1850 MBq generator of a 68Ge/68Ga generator was passed through a cation exchange resin (Strata X-C). 68Ga was adsorbed on the cartridge and rest of the solvent was passed into the waste. A solution conventionally called N2 (mixture of Acetone, metal free water and HCl), was used to release concentrated and purified 68Ga from the strata X-C to the 10 mL reaction vial. The reaction vial contained precursor PSMA dissolved in 1.5 mL 0.25 M sodium acetate at pH of 4.5. The reaction vessel was heated at a temperature of 95˚ C for 15 minutes. After cooling, the solution was diluted by adding 3 ml metal free water. The product was transferred to product vial through 0.22µm sterile filter. All the synthesis steps were carried out in automated module (Modular lab, Eckert and Ziegler, Germany). The total synthesis time was approximately 18 minutes. During the whole procedure radiation level was monitored around the Hot cell at all four side walls at every three minutes. Routine quality control tests done included Radiochemical binding, Rf, pH value and half
Results 68Ga-PSMA yield ranged between 333 to 370 MBq. 68Ga-PSMA conjugate was prepared with very high radiochemical yield and purity (>99 %). The product was stable up to four hours at room temperature (checked by Radio-TLC). During synthesis the radiation level around the hot cell was near background level (~1-2 µSv/hr).
Conclusions Generator based PET radiotracer 68Ga-PSMA can be synthesized with high radiochemical purity and good stability, using an automated module.