Pharmacokinetics and radiation dosimetry estimation of O-(2-[18F]fluoroethyl)-L-tyrosine as oncologic PET tracer.

An easy-to-automate synthetic procedure and the kinetics and radiation dosimetry of O-(2-[18F]fluoroethyl)-L-tyrosine (FET), a recently developed amino acid tracer with potential applications in tumor imaging with PET, are described. FET was prepared in high radiochemical yield, 20-25% with no decay correction, and radiochemical purity of more than 95% in less than 60min synthesis time by a modified two-step procedure and manual operation. The kinetics and radiation dosimetry of FET were evaluated by using mice biodistribution data and the medical internal radiation dosimetry (MIRD) method. The bone (total) was the organ receiving the highest dose, 4.78x10(-3)mGy/MBq, and the brain and the whole body received the lowest dose, 1.6x10(-3)mGy/MBq, respectively. The effective dose was 9.0x10(-3)mSv/MBq. The data show that a 370-MBq (10mCi) injection of FET leads to an estimated effective dose of 3.3mSv and an estimated dose to the whole body of 0.6mGy. The potential radiation risks associated with this study are well within accepted limits.