RT Journal Article
SR Electronic
T1 3-<em>O</em>-Methyl-6-<sup>18</sup>F-Fluoro-<span class="sc">l</span>-Dopa, a New Tumor Imaging Agent: Investigation of Transport Mechanism In Vitro
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 2116
OP 2122
VO 45
IS 12
A1 Bergmann, Ralf
A1 Pietzsch, Jens
A1 Fuechtner, Frank
A1 Pawelke, Beate
A1 Beuthien-Baumann, Bettina
A1 Johannsen, Bernd
A1 Kotzerke, Joerg
YR 2004
UL http://jnm.snmjournals.org/content/45/12/2116.abstract
AB 18F-Labeled amino acids represent a promising class of imaging agents in tumors, particularly brain tumors. However, the determination of their potential to image peripheral tumors, possibly depending on individual transport characteristics, still remains an area of investigation. The present study investigated the transport mechanism for 3-O-methyl-6-18F-fluoro-l-dopa (OMFD), a novel 18F-labeled phenylalanine derivative, into tumor cells. Methods: OMFD has routinely and reliably been prepared for clinical use in 20%–25% radiochemical yield (decay corrected, related to 18F-F2) using 6-18F-fluoro-l-3,4-dihydroxyphenylalanine preparation devices with minor modifications. In vitro uptake assays with HT-29 (human colon adenocarcinoma) cells, FaDu (squamous cell carcinoma) cells, and RBE4 (immortalized rat brain endothelial) cells were performed with OMFD under physiologic amino acid concentrations without and with the competitive transport inhibitors 2-aminobicyclo-[2,2,1]-heptane-2-carboxylic acid and α-(methylamino)isobutyric acid plus serine and without or with Na+. Results: Transport inhibition experiments using specific competitive inhibitors demonstrated that uptake of OMFD in all cell lines tested was mediated mainly by the sodium-independent high-capacity amino acid transport systems. The highest OMFD uptake was in FaDu cells. Conclusion: OMFD seems to be a promising PET tracer for imaging of amino acid transport in tumors.