移动式头部锥形束CT(CBCT)周围剂量场分布测试  

Measurement of dose field distribution around mobile cone beam computed tomography(CBCT)

作　　者：宗睿[1] 王楠 薄文柱 刘磊[1] 翟贺争 高杰[4] 曹文田[5] 余新光[1] 翟自坡 ZONG Rui;WANG Nan;BO Wenzhu;LIU Lei;ZHAI Hezheng;GAO Jie;CAO Wentian;YU Xinguang;ZHAI Zipo(General Hospital of People's Liberation Army,Beijing 100853 China;Tianjin Jinxi Medical Equipment Co.,Ltd.,Tianjin 300385 China;Tianjin University,Tianjin 300072 China;Institute of Radiology,Chinese Academy of Medical Sciences,Tianjin 300110 China;Peking University,Beijing 100871 China;Hunan Prevention and Treatment Institute for Occupational Diseases,Changsha 410007 China)

机构地区：[1]中国人民解放军总医院,北京100089 [2]天津金曦医疗设备有限公司,天津300385 [3]天津大学,天津300072 [4]中国医学科学院放射医学研究所,天津300110 [5]北京大学,北京100871 [6]湖南省职业病防治院,湖南长沙410007

出　　处：《中国辐射卫生》2021年第5期638-642,共5页Chinese Journal of Radiological Health

基　　金：湖南省卫生计生委科研计划课题项目(C2017062)。

摘　　要：目的测量移动式头部锥形束CT(CBCT)的周围剂量分布水平,评估该设备运行中对周围人员及环境的影响,为临床辐射防护管理提供数据支撑。方法结合移动式头部锥形束CT(CBCT)的自身结构特点,以CT孔径正前方为0°(逆时针方向)、45°、90°、135°、180°、225°、270°和315°方向,采用AT1123剂量率仪分别测量该设备正常情况出束时距离地面30 cm、80 cm和130 cm平面的周围剂量当量率,并划出临时控制区的边界;同时测量距设备外表面1 m处铅屏风后的剂量水平并作分析。结果移动式头部锥形束CT(CBCT)周围剂量场以0°和180°为分界线呈对称分布,且0°方向的5.5 m、45°方向的3.5 m、90°方向的0.5 m及180°方向的1.0 m以内区域("勺"型内部)辐射剂量水平高于2.5 μSv/h;距设备表面周围1 m铅屏风后的CT孔径0°(正前方)、45°和315°的辐射剂量水平分别为0.37 μSv/h、0.22 μSv/h和0.54 μSv/h。结论移动式头部锥形束CT(CBCT)周围辐射剂量处于低剂量水平;所得剂量场的分布可为行政、医疗机构人员加强辐射安全管理工作提供必要的参考,同时建议临床使用移动CT场所设置铅屏风,确保周围人员的健康和环境安全。Objective To measure the peripheral dose distributions of the mobile head cone beam computed tomography(CBCT) and evaluate the impact of CBCT on the surrounding personnel and environment, and provide data support for clinical radiation protection management. Methods Combined with the structural characteristics of CBCT, AT1123 was used in the direction of 0°(counterclockwise), 45°, 90°, 135°, 180°, 225°, 270° and 315° in front of CBCT to measure the ambient dose equivalent rate of 30 cm, 80 cm and 130 cm away from the ground when the equipment was normally out of the beam, and the boundary of the temporary control area was drawn. At the same time, the dose level behind the lead screen 1 m away from the external surface of the equipment was measured and analyzed. Results The dose field around CBCT was symmetrically distributed with the dividing line of 0° and 180°, and the radiation dose level of 5.5 m in the direction of 0°,3.5 m in the direction of 45°, 0.5 m in the direction of 90° and within 1.0 m in the direction of 180°(inside the "spoon" type)was higher than 2.5 μSv/h. The radiation dose levels of CT aperture 0°(straight forward), 45° and 315° behind the lead screen 1 m away from the equipment surface were 0.37 μSv/h, 0.22 μSv/h and 0.54 μSv/h, respectively.Conclusion The results show that the radiation dose around the mobile head cone beam CT is in a low dose level, the distribution of the dose field can provide necessary reference for the administrative and medical personnel to strengthen the radiation safety management. At the same time, it is suggested that lead screens should be set up in the clinical use of mobile CT to ensure the health and safety of the surrounding people and the environment.

关 键 词：移动CT CBCT 辐射安全 剂量水平 

分 类 号：X591[环境科学与工程—环境工程]