High-yielding, automated production of 3'-deoxy-3'-[¹⁸F]fluorothymidine using a modified Bioscan Coincidence FDG reaction module

Introduction: High-yielding, automated production of a PET tracer that reflects proliferation, 3'-deoxy-3'-[¹⁸F]fluorothymidine ([¹⁸F]FLT), is reported using a modified Bioscan Coincidence FDG reaction module. Methods: Production of [¹⁸F]FLT was implemented through: (1) modification of an original FDG manifold; (2) application of an alternate time sequence; and (3) altered solid-phase extraction (SPE) purification. Quality control testing, including standard radiochemical figures of merit and preclinical positron emission tomography (PET) imaging, was carried out. Results: High decay-corrected yields of [¹⁸F]FLT (16-39%) were reproducibly obtained. The product exhibited very high specific activity (4586.9TBq/mmol; 123,969Ci/mmol) and radiochemical purity (>99%). Overall, the [¹⁸F]FLT produced in this manner was superior to typical productions that utilized a GE TRACERlab FX_F-N reaction module. Additionally, purification with SPE cartridges, followed by manual elution, accelerated overall run time and resulted in a two-fold increase in [¹⁸F]FLT concentration. PET imaging showed the [¹⁸F]FLT produced by this method was highly suitable for non-invasive tumor imaging in mice. Conclusions: The Bioscan Coincidence GE FDG Reaction Module was readily adapted to reproducibly provide [¹⁸F]FLT in high yield, specific activity, and radiochemical purity. The approach was suitable to provide sufficient amounts of material for preclinical studies.