摘要
目的:比较鼻咽癌千伏级锥形束CT(CBCT)不同配准方式得出的配准结果,为摆位修正提供参考。方法:回顾性分析2018年5月~2019年8月在广州医科大学附属肿瘤医院进行治疗的100例鼻咽癌患者的CBCT图像。按照大区域(Large)即全扫描范围、小区域(Small)即计划靶区范围、骨性(Bone)、灰度(Grey)的不同组合方式,对千伏级CBCT图像分别采用大区域骨性(LB)、大区域灰度(LG)、小区域骨性(SB)、小区域灰度(SG)这4种方式进行配准,并对平移误差和旋转误差结果进行分析。结果:4种方式等中心点平移误差均值范围为-0.29~1.07 mm,旋转误差均值范围为-0.10°~0.61°。除LB与SB在Y方向的平移误差存在显著性差异(P=0.00)之外,其余平移和旋转误差均无显著性差异(P=0.05~0.82)。LG与SG的所有平移和旋转误差均无显著性差异(P=0.14~0.64)。而LG与LB相比除Y方向的平移和旋转误差无显著性差异(P=0.67,0.57)外,其余所有误差均有显著性差异(P=0.00~0.02)。SB与SG相比除X方向平移误差和Y方向旋转误差无显著性差异(P=0.36,0.72)外,其余所有误差均有显著性差异(0.00~0.02)。Pearson相关性分析表明三维方向上所有平移和旋转摆位误差结果均呈正相关(R=0.48~0.98,P<0.01)。采用LG和SG进行配准得出的摆位误差在X、Y、Z平移和旋转方向上的95%一致性限度分别为[1.19,-1.25]、[0.95,-1.01]、[1.13,-1.31]和[0.80,-0.85]、[0.69,-0.60]、[1.02,-1.13]。按照2 mm和2°界值标准二者摆位误差具有一致性。结论:在鼻咽癌的图像引导放疗中用千伏级CBCT进行自动模式下的图像配准时,三维方向上的配准结果可能因骨性或灰度配准方式的不同而有差别。配准区域选择靶区或全扫描范围时,配准结果差异不明显。
Objective To compare the results obtained by different registration methods in the kilo-voltage cone-beam computed tomography(CBCT)image-guided radiotherapy for nasopharyngeal carcinoma(NPC)for providing a reference for setup correction.Methods The CBCT images of 100 NPC patients who were treated in the Cancer Hospital of Guangzhou Medical University between May 2018 and August 2019 were analyzed retrospectively.Two registration areas,namely large area(the whole scanning area)and small area(planning target volume),and two registration algorithms,namely bone and grey registration algorithms,were adopted in the study.According to different combinations of the registration area and different registration algorithms,4 registration methods,namely large area and bone registration(LB),large area and grey registration(LG),small area and bone registration(SB),and small area and grey registration(SG),were used for kilo-voltage CBCT image registration.The translation errors and rotation errors were analyzed.Results The average translation error range of the isocenter after the registration with 4 different methods was-0.29~1.07 mm,and the average rotation error ranged from-0.1°to 0.61°.No significant differences were found between LB and SB in the translation and rotation errors(P=0.05-0.82),except for the translation error in Y direction(P=0.00);and there was no statistical difference between LG and SG in all translation and rotation errors(P=0.14-0.64).Moreover,significant differences were found between LG and LB in the translation and rotation errors(P=0.00-0.02),except for the translation and rotation errors in Y direction(P=0.67,0.57);and the comparison between SB and SG showed that there were significant differences in translation and rotation errors(P=0.00-0.02),except for the translation errors in X direction and the rotation error Y direction(P=0.36,0.72).The result of Pearson correlation analysis revealed that there were positive correlations between any two registration methods in translation and rotation errors in X,Y and Z directions(R=0.48-0.98,P<0.01).With the registration of LG and SG,the 95%limits of agreement(Lo A)of translation errors in X,Y and Z directions was[1.19,-1.25],[0.95,-1.01],[1.13,-1.31],and that of the rotation errors was[0.80,-0.85],[0.69,-0.60],[1.02,-1.13].The setup error was consistent,according to the 2 mm and 2°boundary standards.Conclusion When kilo-voltage CBCT is used for automatic image registration in imageguided radiotherapy for NPC,the registration results in three-dimensional directions may be different due to different registration modes(bone or grey registration);and with the full scanning area or planning target volume as registration area,the registration results are similar.
作者
张国前
张书旭
曾庆星
罗松桂
李萍
阳露
王琳婧
周露
王锐濠
廖煜良
ZHANG Guoqian;ZHANG Shuxu;ZENG Qingxing;LUO Songgui;LI Ping;YANG Lu;WANG Linjing;ZHOU Lu;WANG Ruihao;LIAO Yuliang(Department of Radiotherapy,Cancer Hospital of Guangzhou Medical University,Guangzhou 510095,China)
出处
《中国医学物理学杂志》
CSCD
2020年第3期282-288,共7页
Chinese Journal of Medical Physics
基金
广州市卫生和计划生育科技项目(20181A011098)。
关键词
鼻咽癌
千伏级锥形束CT
骨性配准
灰度配准
摆位误差
nasopharyngeal carcinoma
kilo-voltage cone-beam computed tomography
bone registration
grey registration
setup error
