论文部分内容阅读
目的分析鼻咽癌调强放射治疗(IMRT)的摆位误差情况,从而确定摆位扩边的大小。方法选取采用调强放疗的鼻咽癌患者15例,放射治疗过程中每位患者前3次治疗及之后每周拍摄电子射野验证片(正侧位),共拍摄194张。应用电子射野影像系统(EPID)将验证片与数字重建射野影像(DRR)配准,分别测定左、右、头、脚、腹、背(L、R、H、F、A、P)六个方向的摆位误差。结果六个方向的摆位误差90.21%≤2mm,98.63%≤3mm,100%≤5mm。总体系统误差L-0.6mm(±0.88 s),R 0.58mm(±1.02 s),H 0.08mm(±0.71 s),F 0.21mm(±0.54 s),A0.00mm(±1.12 s),P 0.00mm(±0.97 s);随机误差的标准差分别为±0.55,±0.45,±0.56,±0.52,±0.48,±0.4mm;六个方向的摆位扩边值分别为2.59,2.85,2.17,1.72,3.15,2.72mm。结论在EPID系统下进行实时测量和纠正摆位误差,可降低系统误差和随机误差,提高摆位精度。
Objective To analyze the setup errors of IMRT in nasopharyngeal carcinoma to determine the size of the enlarged side of the nasopharyngeal carcinoma. Methods Fifteen patients with nasopharyngeal carcinoma treated with intensity modulated radiotherapy were selected. Each patient was treated for the first three times during radiotherapy and each week afterwards. The electronic radiography system (EPID) was used to register the verifying films and the digitally reconstructed radiological images (DRR). The left, right, head, feet, abdomen and back (L, R, H, F, A, P) Set the error in six directions. Results The setup errors in six directions were 90.21% ≤2mm, 98.63% ≤3mm, 100% ≤5mm. The overall system error was L-0.6 mm (± 0.88 s), R 0.58 mm (± 1.02 s), H 0.08 mm (± 0.71 s), F 0.21 mm (± 0.54 s), A0.00 mm 0.00mm (± 0.97 s). The standard deviations of random errors were ± 0.55, ± 0.45, ± 0.56, ± 0.52, ± 0.48 and ± 0.4 mm, respectively. , 1.72, 3.15, 2.72 mm. Conclusion Real-time measurement and correction of setup errors under the EPID system can reduce system errors and random errors and improve positioning accuracy.