title: Selective 2-[18F]fluorodopa uptake for melanogenesis in murine metastatic melanomas.
abstract: The relationship between 3,4-dihydroxy-2-[18F]fluoro-L-phenylalanine (2-[18F]FDOPA) uptake and melanogenesis was studied using mice bearing two B16 melanomas: B16-F1 has a higher melanin synthesis ability and a slower growing rate than the higher metastatic B16-F10. A significantly higher 2-[18F]FDOPA uptake by B16-F1 than by B16-F10 and a reverse relationship for the uptake of [14C] 2-deoxy-2-fluoro-D-glucose and [3H]thymidine were observed 1 hr postinjection. F1-to-F10 ratios of both the 2-[18F]FDOPA uptake and the acid-insoluble radioactivity increased to about 5 at 6 hr, which paralleled the melanin content. FM3A mammary carcinoma showed a 2-[18F]FDOPA uptake similar to the B16-F10 but without the acid-insoluble radioactivity. With D,L-DOPA loading, a 55% decreased uptake by FM3A 1 hr postinjection was significantly greater than the 20% reduction in both melanomas. O-Methylated 2-[18F]FDOPA was a predominant acid-soluble metabolite in all tumors. Whole-body autoradiography discriminated the two melanomas clearly. 2-[18F]FDOPA may be a promising tracer for the selective imaging of melanogenesis.
authors.affiliation: Department of Radiology and Nuclear Medicine, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: K
authors.initials: K
authors.lastname: Kubota
authors.forename: R
authors.initials: R
authors.lastname: Kubota
authors.forename: R
authors.initials: R
authors.lastname: Iwata
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Ido
mesh_terms: D000818:Animals; D001345:Autoradiography; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005462:Fluorine Radioisotopes; D008297:Male; D008543:Melanins / Q000096:biosynthesis*; D008546:Melanoma, Experimental / Q000000981:diagnostic imaging* / Q000556:secondary; D051379:Mice; D008810:Mice, Inbred C57BL; D011877:Radionuclide Imaging; D013936:Thymidine; D013997:Time Factors; D014316:Tritium
chemical_list: D005462:Fluorine Radioisotopes; D008543:Melanins; D014316:Tritium; C054651:2-fluorodopa; D004295:Dihydroxyphenylalanine; D013936:Thymidine