Based on mice biodistribution data, absorbed doses in humans due to intravenous administration of ,13,N-NH,3,•H,2,O can be estimated, so as to evaluate the safety of PET diagnosis with ,13,N-NH,3,•H,2,O in humans. ,13,N-NH,3,•H,2,O was injected into mice through a tail vein. At 0, 0.5, 1, 2, 5, 10, 20 and 30 min after the injection, the mice were killed by cervical fracture and biodistribution in mice was determined. Radiation dosimetry in humans was calculated on the base of organ distribution in mice and the standard MIRD method using radioactivity-time curves for humans. The liver in humans received the highest dose of 3.6×10,-3, mGy/MBq. The whole body received the lowest dose of 1.7×10,-3, mGy/MBq, and other organs received doses between 2.4 ×10,-3, and 3.3 ×10,-3, mGy/MBq. The effective dose was estimated to be 1.8×10,-3, mSv/MBq. These results were comparable to values of absorbed doses reported by other authors on radiation dosimetry of this radiopharmaceutacal. Human radiation dosimetry can be performed by the mice biodistribution data and important data for clinical safe trial of ,13,N-NH,3,•H,2,O are provided.