15-(4-(2-[18F]fluoroethoxy)phenyl)pentadecanoic acid ([ 18F]7) was synthesized as a PET probe for assessing myocardial fatty acid metabolism. The radiosynthesis of [18F]7 was accomplished using a two-step reaction, starting with the corresponding tosylate ester, methyl 15-(4-(2-(tosyloxy)ethoxy)phenyl)pentadecanoate (5), and gave the radiolabeled fatty acid, [18F]7 in a radiolabeling yield of 55-60% and a specific activity of >2000 Ci/mmol (decay corrected to EOB). The biological evaluation of [18F]7 in rats displayed high uptake in heart (1.94%ID/g at 5 min), which was higher than the uptake (%ID/g) in blood, lung, muscle, pancreas, and brain. MicroPET studies of [18F]7 in Sprague-Dawley rats demonstrated excellent images of the myocardium when compared with [ 11C]palmitate images in the same animal. Moreover, the tracer kinetics of [18F]7 paralleled those seen with [11C] palmitate, with an early peak followed by biphasic washout. When compared to [11C]palmitate, [18F]7 exhibited a slower early clearance (0.17 ± 0.01 vs 0.30 ± 0.02, P < 0.0001) and a significantly higher late clearance (0.0030 ± 0.0005 vs 0.0006 ± 0.00013, P < 0.01). These initial studies suggest that [18F]7 could be a potentially useful clinical PET tracer to assess abnormal myocardial fatty acid metabolism.