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从理论和实验上提出了两种处理β辐射照射某些浅表组织时的吸收剂量的办法;用年龄-扩散理论计算了~(90)Sr、~(90)Y各自在不同深度处的剂量对总剂量的贡献;用Cross的面源函数表计算了几种放射性核素在对应于某些放射性敏感组织所在深度(<6mm)处吸收剂量与浅表吸收剂量D(0.07)的比值;用组织等效外推电离室和水体模测量了小于6mm深度处的平均吸收剂量和上述比值。理论与实验结果,以及与他人的有关结果都符合得较好。这些数据对于防护人员根据现场测量的两个实用量(定向吸收剂量D′(0.07)和浅表个人吸收剂量D_p(0.07))来评估人体浅表某些重要组织或器官(例如皮肤的敏感层和眼晶体等等)实际所受剂量是否被控制在发生确定性效应的阈值以下及在放疗情况下,对控制某些组织附带受到的照射而施加的剂量约束是很有用的。
Two methods to deal with the absorbed doses of some superficial tissues irradiated by β radiation were put forward theoretically and experimentally. The dose of ~ (90) Sr and ~ (90) Y at different depths were calculated by age-diffusion theory The contribution to the total dose; the Cross’s surface source function table was used to calculate the ratio of the absorbed dose to the superficial absorbed dose D (0.07) for several radionuclides at depths corresponding to some radiosensitive tissues (<6 mm); The tissue equivalent extrapolation ionization chamber and water phantom were used to measure the mean absorbed dose at the depth of less than 6 mm and the above ratios. The theoretical and experimental results, as well as the results of others, are in good agreement. These data evaluate the protection of certain important tissues or organs of the superficial human body (for example sensitive layers of the skin) from two practical doses measured on site (directional absorbed dose D ’(0.07) and superficial absorbed human dose D_p (0.07) And eye lenses, etc.) Whether the actual dose administered is below the threshold for a definitive effect and in the case of radiotherapy, it is useful to control the dose constraints imposed on exposure of certain tissues to irradiation.