【摘要】 目的：探讨全身照射（ＴＢＩ）中为控制肺剂量所采用肺屏蔽挡块对剂量分布的影响。方法：利用三维自动扫描水箱按实际ＴＢＩ照射条件测量三种厚度不同的肺铅挡块下，水模体中剂量分布情况。结果：加肺档块使纵膈区剂量减少，肺挡因子与测量的深度有关。结论：肺挡因子应在照射条件下测量。在全身照射总剂量与肺部限受剂量相差较大时，应注意纵膈剂量的修正。更多还原

【Abstract】 Purpose:To understand effect of lung blocks on dose distribution of total body irradiation to prevent lung from being over irradiated Method: three dimension auto scanning water box was used to measure the dose distribution in water box by three kinds of different thickness lung block according to the actual condition of total body irradiation.Result:① After adding lungs block,mediastinum dose was reduced; ②The shielding factor of lung block was depend on the depth of measurement. Conclusion:The factor of lung block should be measured under the actual condition of total body irradiation.If the deviation between total dose of the body and tolerance dose of lung in the total body irradiation is greater, mediastinum dose should be corrected.更多还原