CT检查床位置对图像质量和辐射剂量影响的实验研究  

Experimental study on the effect of CT examination table position on image quality and radiation dose

作　　者：郭效宾 徐男 李勤勍 柯腾飞 廖承德 杨军[1] GUO Xiao-bin;XU Nan;LI Qin-qing(Yunnan Cancer Hospital,the Third Affiliated Hospital of Kunming Medical University,Kunming 650118,China)

机构地区：[1]云南省肿瘤医院/昆明医科大学第三附属医院放射科,昆明650118 [2]阜外华中心血管病医院放射科,郑州450000 [3]昆明市延安医院/云南心血管病医院/昆明医科大学附属延安医院放射科,昆明650118

出　　处：《放射学实践》2023年第6期679-684,共6页Radiologic Practice

基　　金：国家自然科学基金(82060313);云南省基础研究专项(202201AW070002);云南省科技厅-昆明医科大学联合专项(202001AY070001-072)。

摘　　要：目的:探讨胸部CT扫描过程中检查床位置偏离中心定位时床位高低对辐射剂量及图像质量的影响。方法:对仿真人体模型胸部在7个不同检查床高度进行扫描,对比偏离中心程度与扫描参数、图像质量、辐射剂量间的差异。结果:从最低床高至最高床高,管电流时间乘积、CTDIvol与DLP不断下降,与检查床高度呈线性负相关关系(P<0.001),Pearson相关系数分别为管电流时间乘积(r=-0.98)、CTDIvol(r=-0.977)、DLP(r=-0.974)。不同检查床位置图像的CT值与标准CT值偏差具有统计学差异,上胸气管旁(F=35.37,P=0.00)、上胸背部(F=72.15,P<0.001)、中胸心脏(F=4.06,P=0.014)、中胸背部(F=72.46,P<0.001)、下胸肝脏(F=3.15,P=0.036)、下胸背部(F=19.23,P<0.001)。在上胸背部、中胸背部、下胸背部,当检查床位置偏离中心越大时与标准CT值偏差越大。检查床位置越低时CT值比标准CT值越小,检查床位置越高时CT值比标准CT值越大。上胸背部(F=9.28,P<0.001)、中胸背部(F=4.13,P=0.014)、腹部背部(F=4.37,P=0.011)的图像噪声在检查床位置偏离中心时具有统计学差异,且随检查床从最低到最高依次增大,在检查床位置最高时达到最大值。结论:检查床位置的高低对辐射剂量及图像质量会产生不同程度的影响,位置偏高对CT值测量和图像质量的影响较大,位置偏低会导致辐射剂量增加。Objective:To explore the influence of the height of the examination table on the radiation dose and image quality when the position of the examination table deviates from the central positioning in the process of chest CT scanning.Methods:An adult anthropomorphic phantom was scanned under 7 different heights of the examination table sets.The radiation dose,image quality,scan parameters were compared between different deviation from the center of the chest scanning.Results:From the lowest bed to the highest bed,the tube current time product,CTDIvol and DLP decreased continuously,and there was a linear negative correlation with the table height(P<0.001).The Pearson correlation coefficients were as follows:tube current time product(r=-0.98),CTDIvol(r=-0.977)and DLP(r=-0.974).There were significant differences between CT values and standard CT values in images of different table positions,including upper chest paratracheal(F=35.37,P=0.00),upper chest dorsal(F=72.15,P<0.001),middle chest heart(F=4.06,P=0.014),middle chest dorsal(F=72.46,P<0.001),lower chest(F=3.15,P=0.036)and lower chest dorsal(F=19.23,P<0.001).In the upper chest back,middle chest back and lower chest back,the greater the deviation from the center of the examination table,the greater the deviation from the standard CT value.The lower the table position was,the smaller the CT value was than the standard CT value.The higher the table position was,the greater the CT value was than the standard CT value.The image noise of upper chest back(F=9.28,P<0.001),middle chest back(F=4.13,P=0.014)and lower chest back(F=4.37,P=0.011)has significant difference when the table position deviates from the center.The image noise increased from the lowest to the highest and reached the maximum when the table position was the highest.Conclusion:The position of the examination table will affect the radiation dose and image quality with different degree.The high position will have a great impact on CT values and image quality.The low position will cause the increase of radiat

关 键 词：辐射剂量 体层摄影术 X线计算机 人体模型 图像质量 

分 类 号：R144[医药卫生—公共卫生与预防医学] R814.4R322-34R814