摘要目的 研究锥形束CT(CBCT)图像和CT图像的配准范围对配准精度的影响.方法 对腹部、头部和胸部各5位患者分别进行CBCT和CT扫描,将扫描后各部位图像的配准范围处理成4种模式,模式1为CT配准范围大于CBCT配准范围;模式2为CBCT与CT配准范围相同;模式3是将模式2的CT平移5 cm;模式4是将模式2的CBCT和CT两边同时减少2 cm.4种模式均使用图像分割与配准工具包进行配准,比较4种模式配准后的平均方差测度值,并分析模式2与其他3种模式的关系.结果 平均方差测度值模式3最大,其次是模式1,最小的是模式2和4,且模式2和4的平均方差测度值几乎相等(P＞0.05).对于各部位的模式2与模式1比较,差异有统计学意义(t=-4.586、-4.164、-5.618,P＜0.05);模式2与模式3比较,差异有统计学意义(t=-6.423、-8.109、-19.601,P＜0.05).结论 CBCT和CT图像的配准范围对图像配准精度有一定的影响,CBCT的配准范围与CT的配准范围越接近,配准精度越高.

abstractsObjective To investigate the impact on registration accuracy with the different registration ranges of CBCT images and CT images.Methods CBCT and CT scans were performed on the of 5 patients.The registration ranges of five patients' images of abdomen,head and chest performed CBCT and CT scanning were processed with four modes.Mode 1:the registration range of CT images was larger than the registration range of CBCT images,mode 2:the registration range of CT images and CBCT images were equally,mode 3:taking a 5 cm translation of CT images range from mode 2,mode 4:The CBCT range and CT range reduced 2 cm both sides simultaneously from mode 2.Using the registration program from Insight Segmentation and Registration Toolkit (ITK) to the four modes,the Mean Square Difference (MSD) metric values of four modes after registration were compared and the relationship between mode 2 and another three modes was analyzed by paired t test.Results For the MSD metric values,mode 3 was maximum,mode 2 and 4 were minimum,and mode 1 was centered.The difference between the mode 2 and mode 4 was not statistically significant(P ＞ 0.05).The difference between the mode 2 and mode 1 was statistically significant(t =-4.586,-4.164,-5.618,P ＜ 0.05).The difference between the mode 2 and mode 3 was statistically significant(t =-6.423,-8.109,-19.601,P＜0.05).Conclusion The registration ranges of CBCT and CT images has a certain extent of influence on the accuracy of image registration.The closer the registration range of CBCT and CT is,the higher the registration accuracy is.