ETX线图像引导系统在中上腹部肿瘤SBRT中的临床应用

Clinical application on ETX image guidance system in SBRT of mid-upper abdominal tumor

目的利用ExacTrac X射线图像引导系统(ExacTrac X-ray,ETX),对中上腹部肿瘤的立体定向放射治疗(ster-eotactic radiation therapy,SRT)中的摆位误差进行分析研究,探讨ETX在中上腹部肿瘤中临床应用价值及注意事项.方法选择24例接受SBRT治疗的中上腹部肿瘤患者,并将其分A、B两组,其中A组为肝癌、肾癌及胰腺癌患者,B组为椎骨转移瘤患者.首先用ETX获取六维治疗床校正前的预摆位误差和校正后的残余误差,再利用锥形束CT(cone beam CT,CBCT)进行二次验证并获取验证误差,并对获取的上述三组误差值进行数据分析.结果(1)ETX校正后残余误差比ETX校正前预摆位误差明显减少(P<0.05);(2)ETX校正后,A组患者误差值大于B组患者;(3)CBCT验证平移误差中,A组患者明显大于B组患者;(4)A组患者的CBCT验证误差与ETX校正后残余误差之间差值较大,而B组患者的CBCT验证误差与ETX校正后残余误差之间差值较小.结论对于中上腹部肿瘤SBRT而言,与骨性结构位置密切的椎骨转移瘤,ETX误差精确度媲美CBCT,完全可以代替CBCT进行误差纠正.而对于肝癌、肾癌及胰腺癌等与骨性结构距离较远的肿瘤,ETX误差纠正精度不如CBCT.

Objective Use ExacTrac X-ray(ETX)image guidance system to analyze and study the positioning error in stereotactic body radiation therapy(SBRT)for upper and middle abdominal tumors,and to study the clinical application value of ETX in Mid-upper abdominal tumors.Methods Twenty-four patients receiving SBRT treatment were selected and divided into two groups A and B.Group A was patients with liver cancer,kidney cancer and pancreatic cancer,and group B was patients with vertebral metastases.First,use ETX to obtain the pre-positioning error and residual error after correction of the six-dimensional treatment bed,and then use cone beam CT(CBCT)to perform secondary verification and obtain the verification error,and the obtained three groups Data analysis for error values.Results(1)The residual error after ETX correction was significantly lower than the pre—setting error before ETX correction(P<0.05);(2)After ETX correction,the error value of group A patients was greater than that of group B patients;(3)CBCT verified translation error Among them,the patients in group A were significantly larger than those in group B;(4)the difference between the CBCT verification error of group A and the residual error after ETX correction was large,and the difference between the CBCT verification error of group B and the residual error after ETX correction The difference is small.Conclusion For SBRT of Mid-upper abdomen tumors,vertebral metastatic tumors closely related to bony structures,ETX error accuracy is comparable to CBCT,which can completely replace CBCT for error correction.For liver cancer,kidney cancer,pancreatic cancer and other tumors that are far away from the bone structure,ETX error correction accuracy is not as good as CBCT.