48例脊柱轻度畸形肿瘤患者放疗摆位误差

目的:采用锥形束CT(CBCT)研究脊柱轻度畸形肿瘤患者调强放疗中两种固定方式对摆位精度的影响.方法:随机选取48例脊柱畸形轻度的患者,平均分成A、B两组.A组定位时采用热塑体膜固定,B组采用热塑体膜和负压真空垫协同固定.利用CBCT对每位患者前4次治疗前和第4次治疗后的摆位误差进行测量,SPSS 17.0软件统计分析.结果:A组在左右(X)、头脚(Y)、前后(Z)方向上测量的摆位误差分别为(0.23±0.47)cm、(0.36±0.08)cm、(0.27±0.07)cm,而B组为(0.16±0.06)cm、(0.23±0.12)cm、(0.17±0.04)cm,B组误差数据小于A组,并且差异有统计学意义(P<0.05),其中Y轴误差最大、Z轴次之、X轴最小.第四次治疗后的CBCT数据显示病人在治疗过程中存在位置移动,A组病人移动量大于2mm的占27.5%,B组为8.5%,B组好于A组.结论:热塑体膜协同真空垫固定技术能减少脊柱轻度畸形患者在放疗中的摆位误差.

The setup errors during radiotherapy in 48 tumor patients with spinal mild deformity

Objective:To study the effect of setup accuracy of two fixed ways during radiotherapy in tumor patients with spinal mild deformity by using cone beam CT( CBCT). Methods:All 48 patients with spinal mild deformity were selected at random and divided into A,B two groups,group A used thermoplastic film fixed body,group B with thermo-plastic film and negative pressure vacuum pad fixed together. Setup errors were measured with CBCT in four times be-fore treatments and one time after the forth treatment. Results:The setup errors of group A were(0. 23 ± 0. 47)cm, (0. 36 ± 0. 08)cm,(0. 27 ± 0. 07)cm in media-lateral( X),cranial-caudal( Y),anterior-posterior( Z)direction respectively. Those for group B were(0. 16 ± 0. 06)cm,(0. 23 ± 0. 12)cm,(0. 17 ± 0. 04)cm. The setup errors of group B were smaller than that of group A,and the difference was significant. The errors in axis Y were maximum,me-dium in axis Z,and minimum in axis X. The data were measured by CBCT after the forth radiotherapy showed the set-up locations were changed and the group B was better than A. The location changed over 2mm was 27. 5% in group A,8. 5% in group B. Conclusion:The technology of thermoplastic film and vacuum pad fixed together can reduce set-up errors during radiotherapy in patients with spinal mild deformity.