不同锥形束CT扫描参数对宫颈癌图像质量和摆位误差影响的研究  

Clinical study of the effect of different CBCT scanning parameters on image quality and positioning error of cervical cancer

作　　者：刘莉 叶程伟 袁建军[1] 罗银贵 罗志尧 曾伟 李羚[1] 刘江[1] Liu Li;Ye Chengwei;Yuan Jianjun;Luo Yingui;Luo Zhiyao;Zeng Wei;Li Ling;Liu Jiang(Department of Oncology,Deyang People's Hospital,Deyang 618000,China)

机构地区：[1]德阳市人民医院肿瘤科,德阳618000

出　　处：《中国医学装备》2024年第11期18-24,共7页China Medical Equipment

摘　　要：目的:评估降低管电压锥形束CT(CBCT)扫描参数后对宫颈癌患者图像质量、摆位误差及额外辐射剂量的影响,探索适合宫颈癌患者的扫描条件。方法:选取2020年1月至2022年8月在德阳市人民医院进行放疗的72例宫颈癌患者,按照扫描参数的不同,将其分为低剂量A组(24例,管电压120 kV,管电流154.4 mAs)、低剂量B组(25例,120 kV,228.8 mAs)和常规剂量组[商家提供的扫描序列(23例,120 kV,675.8 mAs)]。通过降低管电压、管电流、减少扫描角度等扫描参数获取CBCT扫描图像,分别获得低剂量A、B组和常规剂量组在左右(x轴)、头脚(y轴)、腹背(z轴)方向的摆位误差配准结果,并进行方差分析。使用X射线容积成像(XVI)自带的Catphan503型模体测量对应的3组图像质量,并进行比较。结果:3组在x、y、z轴3个方向的扫描参数对宫颈癌患者摆位误差比较,差异均无统计学意义(P>0.05)。低剂量A、B组扫描时间为1 min左右,常规剂量组扫描时间为2 min左右;低剂量A、B组和常规剂量组噪声分别为36.51%、26.09%和18.37%,低剂量A组CBCT图像扫描产生的辐射剂量相应降低。结论:降低CBCT扫描参数扫描转速、准直器大小等参数,不会影响摆位误差和图像质量,并可降低扫描时间和放疗患者所受额外辐射剂量。Objective:To assess the effects of the scanning parameters of cone beam computed tomography(CBCT)on image quality,positioning error and additional radiation dose for patients with cervical cancer after tube voltage was reduced,so as to explore scanning conditions that was suitable to patients with cervical cancer.Methods:Seventy-two patients with cervical cancer who received radiotherapy in Deyang People's Hospital from January 2020 to August 2022 were selected.According to different scanning parameters,they were divided into low-dose group A(120 kV,154.4 mAs),low-dose group B(120 kV,228.8 mAs)and conventional group[adopted business-supplied scan sequences(120 kV,675.8 mAs)].The CBCT scan image was obtained by decreasing the tube voltage and tube current,and reducing scanning angle.The registration results of positioning error of low-dose group A,B and conventional group on three directions included left and right(x-axis),head and foot(y-axis)and abdominal and back(z-axis)were respectively obtained,and the results were analyzed by variance analysis.The Catphan503 phantom of X-ray volumetric imaging(XVI)was used to measure the image quality of the corresponding 3 groups,and the further comparison was conducted.Results:There were no significant differences between the three groups in the scanning parameters on x,y and z axis directions for positioning error of patients with cervical cancer(P>0.05).The scanning times of lowdose group A and B were approximately 1 minute,and the scanning time of conventional group was approximately 2 minutes.The noises of low-dose group A and B,and conventional group were respectively 36.51%,26.09%and 18.37%,and the radiation dose that was generated by CBCT image scanning in group A was correspondingly reduced.Conclusion:The reductions of scanning speed and collimator size of CBCT scanning parameters do not affect the positioning error and image quality,and it can decrease the scanning time and additional radiation dose of patients in undergoing radiotherapy.

关 键 词：宫颈癌 扫描参数 锥形束CT(CBCT) 摆位误差 图像质量 

分 类 号：R737.33[医药卫生—肿瘤]