摘要
目的:基于蒙特卡罗仿真模拟方法,研究方舱CT机房内辐射剂量空间分布,为促进医疗机构现有方舱CT的再利用提供参考和数据支撑。方法:采用蒙特卡罗方法和蒙特卡罗粒子输运(MCNP)模拟计算程序,模拟头部模体和体部模体作为CT扫描散射体,在模拟的方舱机房内部,长、宽、高3个方向上每间隔10 cm设置一个剂量模拟计算网格点。在不同准直宽度下分别获取方舱机房内的周围剂量当量分布。使用Matlab软件对MCNP模拟计算结果进行处理,在相应的水平面、垂直面分别绘制0.005 mGy、0.01 mGy、0.015 mGy、0.02 mGy、0.025 mGy和0.03 mGy共6条等剂量分布曲线图。结果:根据模拟计算结果,在水平面、垂直面分别绘制的6条等剂量分布曲线图显示,CT扫描时机房内的辐射场呈不对称的蝶状分布,辐射剂量最大区域(>0.03 mGy)位于CT扫描孔径内,机架两侧区域周围剂量当量<0.005 mGy,相比之下在与CT扫描中心轴成45°角的范围内周围剂量当量处于较高水平。结论:蒙特卡罗仿真模拟方法用于方舱CT空间辐射剂量分布研究结果可靠,可为促进医疗机构现有方舱CT的再利用提供参考和数据支撑。
Objective:To study the spatial distribution of radiation dose in the machine room of computed tomography(CT)of shelter based on the Monte Carlo simulation method,so as to provide references and data support for promoting the reutilization of existing shelter CT of medical institutions.Methods:Monte Carlo method and Monte Carlo N particle(MCNP)transport simulation calculation program were adopted to simulate head and body phantoms as scatters of CT scan.In the inside of the shelter machine room,the grid point of simulation calculation of the doses was set on three directions of length,width and height as the interval of each 10 cm.The equivalent distributions of ambient dose in shelter machine room under different collimation width were respectively obtained.The Matlab software was used to deal with the results of MCNP simulation calculation.A total of 6 curve graphs of isodose distribution,which included 0.005 mGy,0.01 mGy,0.015 mGy,0.02 mGy,0.025 mGy and 0.03 mGy,were respectively drawn on corresponding horizontal and vertical planes.Results:Based on the results of simulation calculation,the 6 curve graphs of isodose distribution that were drawn respectively on horizontal and vertical planes showed that the radiation field in machine room appeared asymmetric butterfly-like distribution during CT scanning.At the same time,the maximum area of radiation dose(>0.03 mGy)was within the aperture of CT scanning.The ambient dose equivalent around the areas on both sides of the gantry was<0.005 mGy.By contrast,the ambient dose equivalent was a relatively high level within the range of 45°angle to the central axis of the CT scan.Conclusion:The research result of Monte Carlo simulation method is reliable in studying the dose distribution of spatial radiation of CT in the shelter,which can provide reference and data support for promoting the reutilization of existing shelter CT of medical institutions.
作者
乔磊
姚金鹏
董硕
张文龙
白玫
QIAO Lei;YAO Jin-peng;DONG Shuo(不详;Department of Medical Engineering,Xuanwu Hospital,Capital Medical University,Beijing 100053,China)
出处
《中国医学装备》
2023年第9期16-19,共4页
China Medical Equipment
关键词
方舱CT
蒙特卡罗
辐射剂量空间分布
辐射场
Computed tomography(CT)of shelter
Monte Carlo
Spatial distribution of radiation dose
Radiation field
