Relationship between dose in teeth and effective dose for photon incidence

Abstract

The relationship between dose in teeth and effective dose was studied for some photon incidences in order to develop a method that enables to predict individual dose based on doses in teeth measured by ESR (Electron Spin Resonance). Absorbed dose in some teeth parts and effective dose were calculated using EGS4 (Electron Gamma Shower version 4) code in combination with a mathematical phantom. Experiments were also performed to determine the absorbed dose distribution in the mouth with TLDs (Thermal Luminescence Dosimeters) put in a head phantom made of tissue equivalent materials. Comparison between calculated and measured results gave a good agreement. Results on relationship between dose in teeth and effective dose can be useful for individual dose estimation in accidental or retrospective situation.

ESR(電子スピン共鳴)を使って測定した歯の中の線量に基づいて個人の線量を予測することが可能となる方法を開発するため、歯中放射線量と有効線量間の関係を幾つかの光子入射について研究した。数学的ファントムと組合わせたEGS4(Electron Gamma Shower version 4)コードを用いて、幾つかの歯の部分の吸収線量と有効線量を計算した。組織等価物質から作った頭部ファントムに取付けたTLD(熱ルミネセンス線量計)を用いて口内の吸収線量分布を定量するための実験も実施した。計算結果と測定結果の比較はよく一致した。歯の中の線量と有効線量間の関係に関する結果は、放射線事故や遡及環境における個人の線量推定にとって有用である。