Kropf R F, Wang Y, Cheng Y S
Lovelace Respiratory Research Institute, Albuquerque, NM 87185, USA.
Health Phys. 1998 Oct;75(4):398-404. doi: 10.1097/00004032-199810000-00006.
Inhaling metal tritide particles is a potential occupational hazard. The radiation dose to tissue from tritide particles depends on their solubility and retention in the body. In each tritide particle, a portion of the beta particles from decay of tritium is absorbed by the metal matrix and therefore cannot contribute to absorbed radiation dose to tissue. A theoretical model for estimating the self-absorption of tritium betas in spherical metal tritide particles is presented. Numerical calculations are made with this method for titanium, zirconium, and erbium particles from 0.5 to 50 microm in diameter. The tritium spectrum is divided into energy groups to facilitate estimation of the energy that escapes the particle for dose calculations. Our results show considerable absorption of beta particles and their energy, even for respirable particles smaller than 5 microm. Limited experimental data of self-absorption for titanium and zirconium tritides supported the theoretical calculation. It is concluded that the self-absorption factors should be required for counting tritide particle samples as well as for estimating absorbed radiation dose to tissue.
吸入金属氚化物颗粒是一种潜在的职业危害。氚化物颗粒对组织的辐射剂量取决于它们在体内的溶解度和滞留情况。在每个氚化物颗粒中，氚衰变产生的一部分β粒子被金属基质吸收，因此不会对组织的吸收辐射剂量产生贡献。本文提出了一个用于估算球形金属氚化物颗粒中氚β粒子自吸收的理论模型。用该方法对直径从0.5到50微米的钛、锆和铒颗粒进行了数值计算。将氚能谱划分为能量组，以便于估算用于剂量计算的从颗粒中逸出的能量。我们的结果表明，即使对于小于5微米的可吸入颗粒，β粒子及其能量也有相当程度的吸收。关于钛和锆氚化物自吸收的有限实验数据支持了理论计算。得出的结论是，在对氚化物颗粒样本进行计数以及估算组织的吸收辐射剂量时，都需要自吸收因子。
