图像引导放射治疗技术提高腹部肿瘤放射治疗精度的临床研究

Image guided radiotherapy enhances the precision of radiotherapy for abdominal tumor

目的对腹部肿瘤采用图像引导放射治疗(IGRT)技术以提高其放疗精度。方法应用Syn-ergyIGRT加速器治疗24例腹部肿瘤患者,通过锥形束CT(CBCT)影像技术获得患者左右(x)、头脚(y)、前后(z)方向的线性摆位误差以及分别以x、y、z轴旋转形成相应的u、v、w旋转摆位误差,分析其摆位误差。结果 24例患者共行458次CBCT,x、y、z、u、v、w轴自由度的系统误差±随机误差分别为(0.15±0.07)cm、(0.08±0.13)cm、(-0.02±0.12)cm、0.76°±0.25°、-0.20°±0.27°、0.20°±0.19°。其中y方向摆位误差最大、z方向次之、x方向摆位误差最小。x、y、z方向的摆位外扩分别为0.57cm、1.09cm、0.66cm。结论 IGRT的应用明显减少了腹部肿瘤患者的摆位误差,提高了治疗精度。为减少摆位误差影响,建议临床耙体积(CTV)外放计划耙体积(PTV)时,在x、y和z方向上分别外扩0.60cm、1.20cm和0.80cm。

Objective To evaluate the precision of image guided radiotherapy(IGRT)for abdominal tumor.Methods A total of twenty-four patients with abdominal tumor were enrolled in this study.Translational errors including left/right(x),superior/inferior(y),anterior/posterior(z)and its corresponding rotational errors(u,v,w)were obtained using CBCT during radiotherapy.Results The data of set-up errors were acquired from 458 sets of CBCT in 24 patients.The determined set-up errors on the axes of x,y,z,u,v and w were(0.15±0.07)cm,(0.08±0.13)cm,(-0.02±0.12)cm,0.76°±0.25°,-0.20°±0.27°and 0.20°±0.19°,respectively.The estimated enlargement margins of set-up were 0.57 cm,1.09 cm,and 0.66 cm in the directions of x,y,and z,respectively.Conclusions The application of IGRT can significantly reduce set-up errors so as to improve the precision of radiotherapy for abdominal tumor.In order to minimize the set-up errors,plan target volume(PTV)can be aquired from the enlarged margins of clinical target volume(CTV)of 0.60 cm,1.20 cm,0.80 cm in the directions of left/right,anterior/posterior and superior/inferior,respectively.