診断用放射性核種を取り扱う核医学作業者の眼球臓器線量評価

OCULAR ORGAN DOSE ASSESSMENT OF NUCLEAR MEDICINE WORKERS HANDLING DIAGNOSTIC RADIONUCLIDES.

抄録

診断用放射性核種を取り扱う核医学作業者の眼球臓器の線量分布を仮想空間でのシミュレーションにより評価した。角膜と水晶体が最も高い線量を受け、線量分布は取り扱う放射線源から放出されるガンマ線エネルギーに比例する傾向があった。さらに、作業者の眼に対するアイウェアプロテクターの線量低減効果を計算した結果、その効果は放出されるガンマ線エネルギーに反比例し、201Tl, 123I, 99mTc, 67Ga, 111In, 18Fの順に線量低減効果が小さくなることがわかった。検討した線源のうち、放出エネルギーが比較的小さい線源、すなわち123I、201Tl、99mTcの線量低減効果は大きく、残りの線源、すなわち18F、111In、67Gaの線量低減効果は小さかった。

The dose distribution in the ocular organs of nuclear medicine workers during the handling of diagnostic radionuclides was assessed via simulation in virtual space. The cornea and lenses received the highest dose, and the dose distribution tended to be proportional to the gamma-ray energy emitted from the radiation source being handled. Moreover, calculations on the dose-reduction effects of eyewear protectors for the eyes of the workers showed that the effects were inversely proportional to the emitted gamma-ray energy, with the dose-reduction effect decreasing in the order of 201Tl, 123I, 99mTc, 67Ga, 111In and 18F. Among the considered sources, the dose-reduction effect was significant for sources that emit relatively less energy, namely 123I, 201Tl and 99mTc, while it was lower for the remaining sources, namely 18F, 111In and 67Ga.