The absorbed and effective radiation doses resulting from the intravenous administration of the potential tumor-imaging PET radiopharmaceutical O-(3-[18F]fluoropropyl)-L-tyrosine (FPT) were estimated using biodistribution data from normal mice. The computer program 3P97 and the methodology recommended by MIRD were used to estimate the doses. The highest uptake of FPT was found in the urinary bladder and pancreas, followed by the liver and kidneys. The urinary bladder wall received the highest absorbed dose of 101.0 microGy/MBq for a 70-kg standard man. The brain received the lowest dose, 6.5 microGy/MBq. Other organs received doses in the range of 6.5-37.5 microGy/MBq. The effective dose was 18.2 microSv/MBq. The data show that a 370-MBq (10 mCi) injection of FPT would lead to an estimated effective dose of 6.7 mSv, which is in the accepted range of routine nuclear medicine investigations.