Synthesis and evaluation of l-5-(2-[18F]fluoroethoxy)tryptophan as a new PET tracer

A convenient remote controlled synthesis of a new tryptophan analog, l-5-(2-[18F] fluoroethoxy)-tryptophan (5-18FEHTP) was described. The radiochemical yield within 65 min was about 12–16% without decay correction, the radiochemical purity was over 98%, and 5-18FEHTP dissolved in saline was stable over 6 h at room temperature. The biodistribution of 5-18FEHTP in mice and the high uptake of 5-18FEHTP in tumor demonstrated that it is very likely a new PET tracer for tumor imaging.