Infrared-based module for the synthesis of 68Ga-labeled radiotracers.
BACKGROUND
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 68Ga-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 68Ga to optimize synthesis conditions. For automation, 250 nmol of DOTA was labeled with 68Ga 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 68Ga-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.


CONCLUSIONS
We demonstrated the use of a commercially available 68Ga/68Ge generator with a semiautomated module to successfully label the bifunctional chelator DOTA with 68Ga. Further investigation with different 68Ga-labeled bioconjugates is warranted to demonstrate the usefulness of the module as a tool for tracer development and imaging research.
Azhdarinia
Ali
A
Department of Experimental Diagnostic Imaging, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Yang
David J
DJ
Chao
Clifford
C
Mourtada
Firas
F
D002626:Chemistry, Pharmaceutical / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005710:Gallium Radioisotopes / Q000737:chemistry*; D006361:Heating / Q000295:instrumentation*; D006358:Hot Temperature; D007259:Infrared Rays; D007553:Isotope Labeling / Q000295:instrumentation* / Q000379:methods; D019275:Radiopharmaceuticals / Q000138:chemical synthesis*; D012371:Robotics / Q000295:instrumentation* / Q000379:methods
D005710:Gallium Radioisotopes; D019275:Radiopharmaceuticals