Abstract
90Sr is one of the most hazardous radionuclides among those released from anthropogenic sources including intentional releases by nuclear plants, radiation accidents and weapon test fallout. 90Sr accumulation in teeth can serve as an important information for dosimetry and it has been tested to be estimated by detecting beta rays with the imaging plate (IP). This study aims at evaluation of 90Sr distribution in teeth. At present, 90Sr deposition is estimated by comparing IP signals between teeth and standard sources containing known amount of 90Sr, assuming the uniform distribution. However, obtained teeth have various shapes with varied sizes, while preparation of standard source for each sample is not practical in measuring a number of samples. Moreover, tooth sample is desired to be thin to avoid suppression of the image resolution, but it is difficult to make thin standard source precisely with uniform 90Sr distribution. Taking into account above, we have proposed a method which uses numerical conversion of an experimental IP response against 90Sr deposition with varied thickness of standard source. The validity of numerical conversion of IP response is verified in this report. For this purpose, the standard sources have been manufactured with varied dimensions and 90Sr concentrations. Simulation based on Fermi theory for beta rays production and Monte Carlo method (MCNP-4C) for its transport is examined for the reproducibility of IP signals. The results will be presented.
