摘要
目的:探究鼻咽癌个体化塑形多感兴趣区图像配准对摆位误差的影响。方法:随机选取43例鼻咽癌放疗的患者,采用发泡胶个体化塑形联合头颈肩热塑膜对其进行体位固定,每周一次CBCT摆位校准。在CBCT图像上,将感兴趣区(ROI)划分为临床使用的全ROI(ROI_(PTV))和7个包含不同颈段结构的局部ROI(ROI_(蝶窦)、ROI_(寰枢椎)、ROI_(颈3)、ROI_(颈4)、ROI_(颈5)、ROI_(颈6)、ROI_(颈7)),分别与定位CT图像配准,记8个ROI在头脚(SI)、左右(LR)、腹背(AP)、Pitch、Roll、Yaw方向的配准误差。结果:SI方向ROI_(颈7)的摆位误差在0.3 cm以内的占89.74%,其余ROI在0.3 cm以内均占90%以上。LR方向随着颈段往上,摆位误差在0.3 cm以内的占比逐渐增加,ROI_(颈7)、ROI_(颈6)、ROI_(颈5)摆位误差在0.3 cm以内的占比分别为76.78%、81.70%和85.26%,其余ROI占比均在90%以上;AP方向除ROI_(寰枢椎)和ROI_(颈3)外,其余ROI摆位误差在0.3 cm以内的占比均低于90%。ROI_(蝶窦)、ROI_(寰枢椎)、ROI_(颈3)、ROI_(颈4)与ROI_(PTV)在SI方向的摆位误差均呈显著正相关(R=0.94、0.95、0.90、0.83);ROI_(蝶窦)与ROI_(寰枢椎)、ROI_(颈3),ROI_(PTV)与ROI_(颈3)在LR方向的摆位误差均呈显著正相关(R=0.95、0.91、0.91);AP方向ROI_(PTV)与ROI_(寰枢椎)、ROI_(颈3)的摆位误差均呈显著正相关(R=0.88、0.90)。8个ROI的外扩为0.38~1.01 cm,其中ROI_(颈6)与ROI_(颈7)在AP方向的外扩均超过0.90 cm,ROI_(颈7)在SI方向的外扩达到0.95 cm。结论:ROI_(PTV)与ROI_(蝶窦)、ROI_(寰枢椎)、ROI_(颈3)在SI、LR和AP方向均存在显著相关性;随着颈段从第三颈椎往下,鼻咽癌患者分段摆位误差逐渐增大;头颈部鼻咽癌患者用发泡胶进行个体化塑形时,鼻咽部和颈椎区域需分段进行外扩。
Objective To explore the effects of image registration using various regions of interest (ROI) on the setup error for nasopharyngeal carcinoma (NPC) patients who were immobilized individually.Methods Forty-three NPC patients who required radiotherapy were enrolled.The patients were immobilized with customized plastic foam and thermoplastic mask,and CBCT verification was performed once a week.In CBCT images,ROI was divided into the whole ROI (ROI_(PTV)) and 7local ROI containing different cervical structures (ROI_(sphenoid sinus),ROI_(atlantoaxial),ROI_(neck3),ROI_(neck4),ROI_(neck5),ROI_(neck6),and ROI_(neck7)),which were then used for registrations with localized CT image.The setup errors in superior-inferior (SI),left-right (LR),anterior-posterior (AP),Pitch,Roll,and Yaw directions were recorded.Results In SI direction,the setup errors within 0.3 cm accounted for 89.74%for ROI_(neck7),and more than 90%for the other ROI.The proportion of setup errors within 0.3 cm gradually increased with the neck upward in LR direction,and they were 76.78%,81.70%,85.26%,and above 90%for ROI_(neck7),ROI_(neck6),ROI_(neck5),and the other ROI,respectively.In AP direction,the proportions of setup errors within 0.3 cm were less than 90%,except for ROI_(atlantoaxial)and ROI_(neck3).The setup errors of ROI_(sphenoid sinus),ROI_(atlantoaxial),ROI_(neck3),and ROI_(neck4)were significantly positively correlated with ROI_(PTV)in SI direction,and the correlation coefficients (R) were 0.94,0.95,0.90,and 0.83,respectively.In LR direction,there were positive correlations between the setup errors of ROI_(atlantoaxial)and ROI_(sphenoid sinus)(R=0.95),ROI_(neck3)and ROI_(sphenoid sinus)(R=0.91),ROI_(PTV)and ROI_(neck3)(R=0.91).The setup errors of ROI_(PTV)in AP direction were positively correlated with ROI_(atlantoaxial vertebrae)and ROI_(neck3)(R=0.88,0.90).The margins of all ROIs ranged from 0.38 cm to 1.01 cm.The extension of ROI_(neck6)and ROI_(neck7)in AP direction exceeded 0.9 cm,and the extension of ROI_(neck7)reached 0.95 cm in SI direction.Conclusion ROI_(PTV)and ROI_(sphenoid sinus),ROI_(atlantoaxial),ROI_(neck3)are significantly correlated in SI,LR,and AP directions.The setup error of nasopharyngeal carcinoma patients gradually increases with the neck down.The nasopharyngeal and cervical regions need to be expanded in segments when patients are immobilized individually.
作者
曹潘潘
王维青
成宇
雷金艳
李师
施小龙
彭海燕
靳富
CAO Panpan;WANG Weiqing;CHENG Yu;LEI Jinyan;LI Shi;SHI Xiaolong;PENG Haiyan;JIN Fu(Radiation Physics Center,Chongqing University Cancer Hospital,Chongqing 400030,China;Department of Imaging,Linyi Third People's Hospital,Linyi 276000,China)
出处
《中国医学物理学杂志》
CSCD
2024年第2期151-157,共7页
Chinese Journal of Medical Physics
基金
重庆市科卫联合医学科研项目(2022DBXM005)。
关键词
鼻咽癌
个体化塑形
多感兴趣区
摆位误差
nasopharyngeal carcinoma
individualized immobilization
multiple regions of interest
setup error
