Abstract: To estimate the human radiation absorbed doses of O-(2-~(18)F-fluoroethyl)-L-tyrosine (FET), mice are considered as model. FET is injected into mice through a tail vein. At 10, 30, 60, 120 and 180 min after injection, the mice are killed by cervical fracture and the biodistribution in mice are determined. Human dosimetric estimation is performed from the biodistribution of FET in mice and the standard Medical Internal Radiation Dose (MIRD) method using time - fractional radioactivity curves for humans. The bone in human is the organ receiving highest dose of 4.78 pGy/Bq, the brain and the whole body receive the lowest dose of 1.6 pGy/Bq, and other organs receive doses between 1.6 and 3.5 pGy/Bq. The effective dose is estimated to be 9.0 pSv/Bq. The data show that a 370 MBq injection of FET leads to an estimated effective dose of 3.3 mSv, which is in the range of routine nuclear medicine investigations. The potential radiation risks associated with this study are well within accepted limits.