Infrared-based module for the synthesis of 68Ga-labeled radiotracers

Introduction: Generator-produced positron emission tomography tracers have gained much attention recently due to favorable imaging characteristics. accessibility and affordability. The focus of this study was to design and validate a semiautomated module for Ga-68-labeled chemistry utilizing infrared-based heating for rapid control of thermal cycle. Methods: A prototype module was built and installed in our laboratory. DOTA (1,4,7,10-tetra-azacyclododecane-1,4,7,10-tetra-acetic acid) was manually labeled (10-1000 nmol) with Ga-68 to optimize synthesis conditions. For automation, 250 nmol of DOTA was labeled with Ga-68 with reaction times of 5 min (n =5), 10 min (n =5) and 20 min (n =6). A dose calibrator and radio-thin-layer chromatography were used to access the product yield and quality of both manual and automated syntheses. Results: A semiautomated 68Ga synthesis module was developed. The system showed that software control could be used to drive a multistep radiochemical synthesis and to produce Ga-68-DOTA with > 95% radiochemical purity, similar to that in manual synthesis. The device also showed that for a short reaction time of 5 min, decay-corrected radioactive yields of > 70% could be achieved. The total synthesis was as short as 22 min, including 6-8 min for HCl evaporation. The temperature and pressure profiles of the process were consistent. Conclusion: We demonstrated the use of a commercially available Ga-68/Ge-68 generator with a semiautomated module to successfully label the bifunctional chelator DOTA with Ga-68. Further investigation with different Ga-68-labeled bioconjugates is warranted to demonstrate the usefulness of the module as a tool for tracer development and imaging research. (c) 2007 Elsevier Inc. All rights reserved.