226Ra concentrations in human teeth from several cities, mainly Tokyo, Japan, were determined with emphasis on the measurement of low-level 226Ra by alpha-ray spectrometry following chemical separation. No appreciable differences in 226Ra concentration were found among various permanent teeth samples of different age groups in Tokyo. The mean 226Ra concentration for Tokyo was 0.51 +/- 0.06 mBq (g Ca)-1. 226Ra concentration [mean: 0.67 +/- 0.11 mBq (g Ca)-1] in teeth in western regions of the country was statistically higher than that [mean: 0.48 +/- 0.09 mBq (g Ca)-1] in eastern ones. The mean 226Ra concentration [0.51 mBq (g Ca)-1] in teeth from Tokyo was less than the concentration [1.11 mBq (g Ca)-1] reported for vertebral bone samples of this city.

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