ATCM技术不同调制模式胸部CT扫描剂量的实验研究

Experimental study of radiation dose in chest CT scanning with different modulation patterns of ATCM technique

目的通过仿真胸部体模CT扫描模拟实验,评价ATCM技术3种调制模式胸部扫描辐射剂量的特点。方法使用Philips公司Brilliance 16层螺旋CT,分别采用ATCM技术的角度调制、Z轴调制和联合调制模式,预置2组管电流(122 mA、296 mA),其他技术参数相同,扫描中国成人男性CDP-IC型仿真胸部体模。存储所有图像并记录CTDI和DLP值,以联合调制作为对照组进行配对资料t检验。结果角度调制和Z轴调制以其技术特点按照仿真胸部体模各层组织结构的变化调制管电流。预置296 mA组,角度调制、Z轴调制与联合调制比较,CTDI和DLP值比较差异有统计学意义(P<0.05)。结论 ATCM技术的3种模式均可不同程度地降低胸部CT扫描辐射剂量,使用联合调制模式降低辐射剂量更为显著。

Objective To evaluate the characteristic of radiation dose in chest CT scanning with different patterns of automatic tube current modulation（ATCM） technique.Methods The Chinese anthropomorphic chest phantom（CDP-IC）was scanned by Brilliance 16（Philips）with three patterns（angular modulation,z-axis modulation and combined modulation）of ATCM technique using two pre-set mA（122mA,296mA）and same others scan parameter.CT dose index（CTDI） and dose-length product（DLP）values were recorded.All data were analyzed by a paired t test.Results Angular modulation and z-axis modulation involves variation of the radiation dose among anatomic regions of chest anthropomorphic phantom by varying the tube current in accordance with its technique characteristic.In group of pre-set 296mA,compared with angular modulation and z-axis modulation,CTDI and DLP value had significant statistically differences（P0.05）.Conclusion Three patterns of ATCM technique can decrease radiation dose in chest CT scanning,the radiation dose reduction of combined modulation technique is more significant than the others.