To estimate the internal dose of a Chinese visiting scholar internally contaminated because of the Cherno- byl Accident, the contents of 134Cs and 137Cs in urine were measured using a Ge(Li) γ-spectrometer. The internal doses were calculated based on data from the ICRP Publications. The effective doses from 134Cs and 137Cs were estimated to be 61 μSv and 98 μ Sv, respectively. The sum of 159 μSv was lower than the total effective dose (310 μSv), from the inhalation and ingestion of natural radionuclides. The dose of 131I was also reviewed referring to the UNSCEAR 2000 Report. The equivalent effective dose of 131I was estimated to be 2.9 mSv, 18 times more than the amount of 134Cs and 137Cs. Therefore, it is considered that the earlier estimation of internal doses of 131I is important in evaluating radiation injuries from a nuclear reactor accident.
