In vitro evaluation of (S)-2-amino-3-[3-(2-F-fluoroethoxy)-4-iodophenyl]-2-methylpropanoic acid (F-FIMP) as a positron emission tomography probe for imaging amino acid transporters.

Background: (S)-2-amino-3-[3-(2-F-fluoroethoxy)-4-iodophenyl]-2-methylpropanoic acid (F-FIMP) as a promising PET probe for imaging the tumor-specific L-type amino acid transporter (LAT) 1. Our previous study revealed that F-FIMP had a higher affinity for LAT1 than for LAT2 abundantly expressed even in normal cells. F-FIMP showed high accumulation in LAT1-positive tumor tissues and low accumulation in inflamed lesions in tumor-bearing mice.

Comparison of [F]FIMP, [C]MET, and [F]FDG PET for early-phase assessment of radiotherapy response.

Several limitations of [F]FDG have been reported, such as nonspecific uptake of inflammation foci. Moreover, [C]MET has been found to accumulate in normal and inflammatory tissues as well as tumors. To increase specificity to tumor tissues, PET probes with tumor-specific molecular targets have been actively developed.

First-in-human assessment of the novel LAT1 targeting PET probe F-FIMP.

In the first-in-human PET study, we evaluated the biodistribution and tumor accumulation of the novel PET probe, (S)-2-amino-3-[3-(2-F-fluoroethoxy)-4-iodophenyl]-2-methylpropanoic acid (F-FIMP), which targets the tumor-related L-type amino acid transporter 1 (LAT1), and compared it with L-[methyl-C]methionine (C-MET) and 2-Deoxy-2-F-fluoro-D-glucose (F-FDG). F-FIMP biodistribution was revealed by whole-body and brain scans in 13 healthy controls. Tumor accumulation of F-FIMP was evaluated in 7 patients with a brain tumor, and compared with those of C-MET and F-FDG.

F-FIMP: a LAT1-specific PET probe for discrimination between tumor tissue and inflammation.

Positron emission tomography (PET) imaging can assist in the early-phase diagnostic and therapeutic evaluation of tumors. Here, we report the radiosynthesis, small animal PET imaging, and biological evaluation of a L-type amino acid transporter 1 (LAT1)-specific PET probe, F-FIMP. This probe demonstrates increased tumor specificity, compared to existing tumor-specific PET probes (F-FET, C-MET, and F-FDG).