Fluorine-18-FPCT: a PET radiotracer for imaging dopamine transporters.
Fluorine-18-labeled 2 beta-carbomethoxy-3 beta-(4-chlorophenyl)-8-[-3-fluoropropyl) nortropane (FPCT) has been synthesized as a new dopamine transporter imaging agent.


METHODS
Fluorine-18 was introduced into 2 beta-carbomethoxy-3 beta-(4-chlorophenyl)-8-[-3-fluoropropyl) nortropane by preparation of 1-[18F]fluoro-3-iodopropane followed by alkylation of 2 beta-carbomethoxy-3 beta-(4-chlorophenyl)nortropane.


RESULTS
Tissue distribution studies in rats with [18F]FPCT showed high striatal uptake (0.70% dose/g at 60 min; 0.38% dose/g at 120 min) and good striatal-to-cerebellum ratios (5.5 at 60 min; 6.2 at 120 min). Imaging studies in rhesus monkeys (n = 2) with [18F]FPCT showed high uptake and retention in the putamen (P) (P = 0.03%-0.12% dose/g; at 115 min) and good putamen-to-cerebellum ratios of 3.40-3.43 at 115 min. Plasma metabolites were analyzed in rhesus monkeys (n = 2) by ether extraction and HPLC. The radioactivity in the ether-extractable fraction displayed a single peak that corresponded on HPLC to unmetabolized authentic FPCT.


CONCLUSIONS
These results suggest that [18F]FPCT is an excellent candidate for PET imaging of dopamine transporters.
Goodman
M M
MM
Emory Center for Positron Emission Tomography, Atlanta, Georgia, USA.
Keil
R
R
Shoup
T M
TM
Eshima
D
D
Eshima
L
L
Kilts
C
C
Votaw
J
J
Camp
V M
VM
Votaw
D
D
Smith
E
E
Kung
M P
MP
Malveaux
E
E
Watts
R
R
Huerkamp
M
M
Wu
D
D
Garcia
E
E
Hoffman
J M
JM
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D003287:Contrast Media; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics*; D008253:Macaca mulatta; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009662:Nortropanes / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
C103655:2-carbomethoxy-3-(4-chlorophenyl)-8-(3-fluoropropyl)nortropane; D002352:Carrier Proteins; D003287:Contrast Media; D050483:Dopamine Plasma Membrane Transport Proteins; D005462:Fluorine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009662:Nortropanes; D019275:Radiopharmaceuticals