RT Journal Article SR Electronic T1 Evaluation of trans-9-18F-Fluoro-3,4-Methyleneheptadecanoic Acid as a PET Tracer for Myocardial Fatty Acid Imaging JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 297 OP 304 VO 46 IS 2 A1 Timothy M. Shoup A1 David R. Elmaleh A1 Ali A. Bonab A1 Alan J. Fischman YR 2005 UL http://jnm.snmjournals.org/content/46/2/297.abstract AB This study describes the radiosynthesis and preliminary biologic evaluation of trans-9(RS)-18F-fluoro-3,4(RS,RS)-methyleneheptadecanoic acid (18F-FCPHA) as a new potential probe for assessing myocardial fatty acid metabolism by PET. This fatty acid, containing a cyclopropyl moiety in the β,γ-position, was designed to enter the myocardium by the same mechanism as natural fatty acids and to undergo partial metabolism before being trapped in the cell. Methods: 18F-FCPHA and the β-methyl analog 8(RS)-18F-fluoro-3(RS)-methylheptadecanoic acid (18F-FBMHA) were prepared from their corresponding mesylate precursors by nucleophilic substitution. The precursors used for labeling were fully characterized, and the data were consistent with the proposed structures. Biodistribution studies of each tracer were performed with Sprague-Dawley rats at 5 and 60 min after injection. Sequential imaging of a rhesus monkey injected with 222 MBq of 18F-FCPHA was performed by use of a microPET camera. Results: At 5 and 60 min, heart uptake values measured as mean ± SD percentage injected dose per gram (%ID/g) in rats for 18F-FCPHA were 1.55 ± 0.72 and 1.43 ± 0.14, respectively. The heart-to-blood ratios at 5 and 60 min, an indication of target definition, were 25.8 and 20.4, respectively. The heart-to-lung ratios at 5 and 60 min were 3.3 and 4.6, respectively. Bone accumulation (%ID/g), an indication of defluorination, was 0.16 ± 0.03 at 5 min and increased to 0.70 ± 0.39 at 60 min. The heart-to-blood ratio obtained with 18F-FBMHA was 2.6 at 5 min and did not change significantly at 60 min. Imaging of the monkey heart after injection of 18F-FCPHA showed an initial spike of activity corresponding to blood flow followed by a plateau at 10 min. Conclusion: The cyclopropyl moiety in 18F-FCPHA does have a significant influence on heart accumulation, as suggested by the high heart-to-blood ratio and the fast blood clearance in rats. These results, along with the remarkable quality of the PET images, indicate the potential of this new class of labeled fatty acids for use in studying heart disease by PET.