Investigation of [67Ga]dimethylgallium(III) acetylacetonate as a potential radiopharmaceutical.

Carrier-added [67Ga]dimethylgallium(III) acetylacetonate, a four coordinate Ga complex with two hydrolytically-stable Ga-C bonds, was prepared at a specific activity of 2.8 mCi/mmol. The biodistribution of this tracer was determined following intravenous injection into rats as a 5% ethanol: 19% propylene glycol solution in saline. Although the myocardial levels of 67Ga were fairly constant over a 2 h time period (%ID/heart = 0.80 +/- 0.19, 0.67 +/- 0.04 and 0.62 +/- 0.07 at 1.30 and 120 min post-injection, respectively), somewhat slow clearance of activity from the blood would preclude the use of this organometallic gallium complex as a myocardial imaging agent.