胸部肿瘤放疗用颈胸模固定添加体表标记线对摆位误差的影响

The effects of adding the surface marker line on the placement error of the chest tumor with radiotherapy

目的探讨胸部肿瘤放疗用颈胸模固定添加体表标记线对摆位误差的影响。方法选取本科2018年8月至2019年5月治疗的胸部肿瘤患者98例,分为观察组与对照组,各49例。对照组给予常规颈胸模固定,观察组在对照组固定的基础上给予体表标记线。所有患者均使用Varian TrueBeam医用直线加速器给予容积调强放射治疗(VMAT),用机载的Cone-Beam CT(CBCT)进行图像验证,验证患者摆位误差,每例患者进行CBCT 7次,观察组和对照组各343次,与定位CT进行比较,记录相应的摆位误差。对比研究每例患者X(左右方向)、Y(进出方向)、Z(升降方向)、Rtn(旋转方向)摆位误差。结果观察组放疗期间X(左右方向)、Rtn(旋转方向)的摆位误差都显著优于对照组(P<0.05),Y(进出方向)、Z(升降方向)的摆位误差与对照组比较差异无统计学意义。观察组放疗期间的摆位校正率对比为0%,显著少于对照组的12.2%(P<0.05)。结论胸部肿瘤放疗用颈胸模固定添加体表标记线能抑制X(左右方向)和Rtn(旋转方向)上的摆位误差,降低摆位校正率。

Objective To investigate the effects of the addition of body surface marker lines on the placement error of cervical thoracic cavity ra diotherapy for thoracic tumor radiotherapy.Methods Used a retrospective analysis,from August 2018 to May 2019,98 patients with chest tumors were selected and treated in our hospital and were equally divided into the observation group and control group accorded to the random number table method,with 49 cases in each group.All patients were treated with volumetric intensity-modulated radiation therapy(VMAT)by using Varian True Beam medical linear accelerator.Image-based Cone-Beam CT(CBCT)were used to verify the patient's placement error.Each patient underwent CBCT 7 times that the observation group and control group were 343 times in each group.Compared with the positioning CT and recorded the corre sponding placement error.Compared the error of each patient X(left and right direction),Y(in and out direction),Z(lifting direction),and Rtn(rota tion direction).Results The placement error of X(left and right direction)and Rtn(rotation direction)during observation group were significantly better than that of the control group(P<0.05),there was no significant difference between the swing errors of Y(in and out direction)and Z(in and out direction)and the control group.The contrast correction rate during the observation group were 0%,which were significantly lower than 12.2%of the control group(P<0.05).Conclusion The addition of body surface marker lines to the chest tumor model for thoracic tumor radiotherapy can reduce the placement error of X(left and right direction)and Rtn(rotation direction),and it can reduce the position correction rate.