吸入氡子体肺部有效剂量转换系数的影响因素研究

Study on the influencing factors of pulmonary effective dose conversion coefficient of inhaled radon progeny

基于ICRP 66号报告中的呼吸道生物动力学模型,采用MATLAB软件中的Simulink仿真工具,建立了人体呼吸道的廓清模型,利用建立的廓清模型计算了不同参数条件下肺部有效剂量转换系数(mSv/WLM)的变化规律。结果显示吸入氡子体粒径对肺部有效剂量转换系数的影响最大,当粒径在0.7~10000 nm之间变化时,肺部有效剂量转换系数的变化能达到10倍以上;其次是呼吸率,呼吸率直接决定了吸入氡子体粒子的数量,当成年男性重度工作状态时肺部有效剂量转换系数是睡眠状态下的4.2倍;未结合态份额对剂量转换系数的影响会随着吸入氡子体粒径值不同而发生改变,当未结合态份额从0变化到0.08时,肺部有效剂量转换系数最多能增大79%;相比而言吸收入血速率对肺部有效剂量转换系数的影响只有不到4%。

Based on the respiratory tract biodynamic model in ICRP 66 report,this paper established the clearance model of human respiratory tract by using Simulink simulation tool in MATLAB software.The variation of pulmonary effective dose conversion coefficient(mSv/WLM)under different parameters was calculated by using the clearance model.The results showed that the particle size of inhaled radon progeny had the greatest influence on the lung effective dose conversion coefficient.The lung effective dose conversion coefficient could change more than 10 times when the particle size range was between 0.7 nm and 10,000 nm.The second factor is respiration rate,which directly determines the number of radon daughter particles inhaled.The lung effective dose conversion coefficient of a male under heavy working state is 4.2 times that of a male under sleep state.The effect of unbound state fraction on dose conversion coefficient will change with the size of inhaled radon daughters.When the unbound state fraction changes from 0 to 0.08,the lung effective dose conversion coefficient can increase by 79%at most.In contrast,absorbed blood rate only affects the pulmonary effective dose conversion coefficient by less than 4%.