基于蒙特卡罗仿真模拟的方舱CT检查患者辐射剂量研究

Study on the radiation dose of patient received CT examination in shelter based on Monte Carlo simulation

目的:基于蒙特卡罗仿真模拟方法,研究方舱机房环境下的CT检查患者剂量。方法:采用蒙特卡罗方法和MCNP程序模拟联影uCT530机型,模拟头部模体和体部模体的CT剂量指数(CTDI)测量。对比分析CT扫描中相同管电压、管电流和准直宽度条件下模拟获取的常规机房CTDI值与产品技术手册中CTDI值的差异性;并分别对相同扫描条件下的常规机房与方舱机房的头部模体和体部模体的CTDI值进行对比分析。结果:常规机房内体部模体和头部模体的CTDI值模拟结果与产品技术手册中相应CTDI值比较,差异均无统计学意义(t=-1.39,t=-2.814;P>0.01)。常规机房与方舱机房之间,准直宽度分别为11 mm和22 mm条件下体部模体和头部模体CTDI值模拟结果比较,差异均无统计学意义(t_(体部模体)=3.909,t=9.54;t_(头部模体)=3.796,t=3.958;P>0.01)。结论:基于蒙特卡罗仿真模拟方法用于方舱CT检查患者剂量研究结果可靠。尽管方舱CT机房的面积和最小单边长度均小于常规机房的标准要求,但其不会显著增加CT检查患者的辐射剂量。

Objective:To study the doses of patients who received computed tomography(CT)examination under the environment of shelter machine room based on Monte Carlo simulation.Methods:The Monte Carlo method and MCNP program were used to simulate uCT530 model that was manufactured by United Imaging,as well as to simulate the measurement for the CT dose index(CTDI)of head phantom and body phantom.The differences of CTDI value between conventional machine room and product technique manual were compared and analyzed under same tube voltage,tube current and collimation width in CT scan.The CTDI values of head phantom and body phantom between the conventional machine room and the shelter machine room were respectively compared and analyzed under same scan condition.Results:There were no significant differences between the simulated CTDI values of body phantom and head phantom and the corresponding CTDI values of product technique manual in the conventional machine room(t_(body phantom)=-1.39,t_(head phantom)=-2.814,P>0.01),respectively.There were no significant differences in the simulated CTDI values of body phantom and head phantom under different collimation widths(11 mm and 22 mm)between the conventional machine room and shelter machine room(t_(body phantom)=3.909,t=9.54,t_(head phantom)=3.796,t=3.958,P>0.01).Conclusion:The result based on Monte Carlo simulation method shows reliability when it is used to study the dose of the patient who receives CT examination in shelter.Although both the area and minimum unilateral length of the shelter CT machine room are smaller than the standard requirement of conventional machine room,it will not increase the radiation dose of patient who receives CT examination.