摘要: |
目的:探讨图像引导放射治疗(image guided radiation therapy,IGRT)技术在测定并校正肺部恶性肿瘤体部立体定向放射治疗(stereotactic body radiation therapy,SBRT)过程中靶区位置误差的意义。
方法:选择复旦大学附属肿瘤医院收治的14例肺部恶性肿瘤并接受SBRT的患者。每次治疗前后均进行千伏级锥形束CT (kV CBCT)扫描,与计划CT图像进行在线配准,校正误差后进行治疗。治疗后再次进行CBCT扫描并配准。分别记录治疗前后靶区位置误差。根据临床靶区(CTV) 计划靶区(PTV)外放公式MPTV(外放)=2.5Σ+0.7σ计算PTV外扩大小。
结果:治疗前靶区位置左右、头脚、腹背方向误差最大值分别为10.0 mm、16.9 mm、8.7 mm,误差平均值分别为(2.4±2.8) mm、(3.4±4.6) mm、(2.9±3.4) mm。在线校正并治疗后,靶区位置左右、头脚、腹背方向的误差最大值分别为7.6 mm、4.6 mm、7.0 mm,误差平均值分别为(2.1±2.0) mm、(1.5±1.6) mm、(1.7±2.0) mm。无图像引导PTV外扩大小为左右7.96 mm、头脚11.72 mm、腹背9.63 mm,有图像引导并在线校正PTV外扩大小为左右6.65 mm、头脚4.87 mm、腹背5.65 mm。
结论:IGRT技术可即时校正SBRT治疗前由摆位引起的靶区位置误差,并测定治疗过程中的靶区位置移动,能提高治疗精度,并有助于PTV外扩的制定。 |
关键词: 图像引导放射治疗 体部立体定向放射治疗 误差 计划靶区 |
DOI:10.12025/j.issn.1008-6358.2016.20160115 |
分类号: |
基金项目: |
|
|
|
|
Abstract: |
Objective:To discuss the significance of image guided radiation therapy(IGRT) technique in measuring and correcting of target position errors in stereotactic body radiotherapy (SBRT) treatment for lung cancer.
Methods:Totally 14 cases underwent SBRT treatment were enrolled in this study. Patients were scanned by kilo voltage cone beam CT (KV CBCT) before and after treatment, and online registered to the planning CT images; the target position error was corrected before treamtnet, and the CBCT was scanned and registered again after treatment. The target position errors were recorded before and after treatment. The CTV PTV margin was calculated by the formula 2.5Σ+0.7σ.
Results:The maximum pre treatment error in right left, head feet and back belly directions were 10 mm, 16.9 mm and 8.7 mm,respectively. The mean value of target position errors in right left, head feet and back belly directions were (2.4±2.8) mm,(3.4±4.6) mm and (2.9±3.4)mm,respectively. The maximum post treatment target position errors in right left, head feet and back belly directions after online correction were 7.6 mm,4.6 mm, and 7.0 mm, respectively, and the mean values were (2.1±2.0)mm,(1.5±1.6) mm and (1.7±2.0) mm,respectively. Without the usage of image guide, the PTV margins in right left, head feet and back belly directions were 7.96 mm, 11.72 mm and 9.63 mm, respectively; with the usage of image guide, the PTV margins in right left, head feet and back belly directions were 6.65 mm,4.87 mm and 5.65 mm, respectively.
Conclusions:The IGRT technology can online correct the pre treatment target position errors and determine the target position removing during treatment. It can improve the treatment accuracy, and contribute to set the PTV margins. |
Key words: image guided radiation therapy stereotactic body radiation therapy error planning target volume |