PNNL

Abstract

Human teeth have been considered as dosimeters for decades. Methods include the in vivo measurement of 90Sr/90Y in teeth with a tooth-beta counter (TBC), the radiochemical determination of 90Sr in whole teeth, and the measurement of dose in teeth by use of electron paramagnetic resonance (EPR). Presented in this paper are results of 2,514 TBC measurements, 334 radiochemical measurements, and 218 EPR measurements for residents living in settlements along the Techa River. All three kinds of measurements indicate a sharp peak that corresponds to the uptake of 90Sr by tooth tissue. The results can be interpreted in terms of an intake function for 90Sr only if the period of calcification of each individual tooth is considered—such detail on a tooth by tooth basis is presented in this paper. The conclusion is reached that the TBC data are the most reliable in terms of reconstruction of 90Sr intake; this is due in part to the fact that the TBC measures four teeth (all at position 1) with essentially the same time periods of mineralization and because there are a large number of TBC measurements. The main utility of EPR measurements is considered to be the validation of estimates of external dose; but for this purpose teeth with 90Sr taken up into enamel must be avoided.