体表引导自动摆位在盆腔肿瘤放疗中的临床应用价值

Clinical application value of surface-guided automatic positioning in pelvic tumor radiotherapy

背景与目的:放疗作为对抗盆腔肿瘤的重要手段,如何增进放疗准确性且提高疗效成为目前研究的重点。本研究旨在比较分析体表引导放射治疗(surface guided radiation therapy,SGRT)自动摆位与传统体表标记摆位在患者临床放疗时摆位误差大小方面的影响。方法:回顾性分析复旦大学附属肿瘤医院2023年4月—2024年4月接受放射治疗且行简易体位固定方法的盆腔肿瘤患者。按照两种摆位技术准则进行摆位后采集锥形束X射线计算机体层成像(cone beam computed tomography,CBCT)影像,与初始定位参考CT图像进行六维方向的比对后校正治疗。记录六维方向的校正误差值,使用SPSS 27.0对两组患者数据进行统计学分析,计算均值、标准差及数值在不同区间分布的个案数与概率,并对观察组患者进行六维方向的相关程度进行分析。结果:共50例患者纳入本研究,其中观察组患者(25例)采用自动摆位标记,对照组患者采用(25例)体表标记。两组相比较仅在头脚与俯仰角方向出现显著差异(P<0.05)。观察组各方向误差小于3 mm及小于1°的个案数(概率)分别为108(86.4%)、93(74.4%)、108(86.4%)及96(76.8%)、111(88.8%)、107(85.6%),对照组为113(90.4%)、107(85.6%)、118(94.4%)和71(56.8%)、95(76.0%)、110(88.0%)。Spearman相关系数分析显示,观察组中左右与俯仰角、横滚角及偏转角方向呈负相关,其余方向均呈正相关,其中头脚与俯仰角、左右与横滚角、俯仰角与横滚角的差异有统计学意义(P<0.05),且呈正相关关系(r=0.270、r=0.301、r=0.247)。结论:应用SGRT自动摆位可以达到常规体表标记线摆位的效果,在旋转方向调整具有优势,在条件允许的情况下可以替代体表标记线摆位。

Background and purpose:Radiotherapy is an important means to treat pelvic tumors.It is important to improve the accuracy of radiotherapy and enhance the effectiveness.This study aimed to compare and analyze the influence of positioning errors during the radiotherapy of patients using surface guided radiotherapy(SGRT)automatic positioning versus traditional surface marking positioning.Methods:We performed a retrospective analysis of 50 patients with pelvic tumors who received radiotherapy and had simple positioning fixation methods at the Fudan University Shanghai Cancer Center from April 2023 to April 2024.A total of 25 patients were treated using SGRT(observation group),and 25 patients were treated using traditional surface marking(control group).After positioning according to the two positioning techniques,cone beam computed tomography(CBCT)images were collected.These data were compared with the initial reference computed tomography(CT)images within 6 dimensions.The correction error values of the six dimensions were recorded.We calculated the averages,standard deviations,and the number of cases and probabilities in different interval distributions.SPSS 27.0 was used to perform statistical analysis of the data from the two groups of patients.We also analyzed the correlation of patients in the observation group within the 6 dimensions.Results:The non-parametric test showed significant differences in only the LNG and PITCH directions(P<0.05).The number of cases(probability)in the observation group with errors less than 3 mm and less than 1 were 108(86.4%),93(74.4%),108(86.4%),and 96(76.8%),111(88.8%),107(85.6%),respectively.In the control group,the numbers were 113(90.4%),107(85.6%),118(94.4%),and 71(56.8%),95(76.0%),110(88.0%),respectively.The Spearman correlation analysis showed that in the observation group,the left-right direction had a negative correlation with pitch,roll and yaw,while all other directions were positively correlated.Statistically significant positive correlations(P<0.05)were found between the superior-inferior and pitch directions,left-right and roll directions,as well as pitch and roll directions,with positive correlation coefficients(r=0.270,r=0.301,and r=0.247).Conclusion:The application of SGRT automatic positioning can achieve the effect of regular surface marking line positioning,has advantages in rotation direction adjustment,and can replace surface marking line positioning where conditions permit.