影像引导下放射治疗脊柱肿瘤六自由度摆位误差分析

发布时间：2018-04-02 02:26

本文选题：脊椎肿瘤　切入点：放射疗法　出处：《北京大学学报(医学版)》2015年06期

【摘要】：目的:探讨颈椎、胸椎及腰椎肿瘤在锥形束CT(cone beam CT,CBCT)影像引导下的调强放射治疗(image guided radiation therapy,IGRT)六自由度摆位误差分析。方法:收集2013年5月至2014年6月在北京大学第三医院行脊柱恶性肿瘤放疗的患者30例,其中颈椎肿瘤10例,胸椎肿瘤10例,腰椎肿瘤10例。采用瑞典医科达(ELEKTA)公司AXESSE直线加速器CBCT引导,用Hexa PODTMevoRT床从平移和旋转六自由度方向在线校正摆位误差,CT模拟定位获取治疗计划参考图像(层厚3 mm,120 k V,200 m As)。每次治疗前行千伏级(k V级)CBCT扫描(100 k V,36.6 m As,s20射野准直器),CBCT图像采用骨窗模式与计划参考图像自动匹配,并经高资质医师和物理师共同确认,误差校正后再次行CBCT扫描,将两次图像与计划参考图像分别进行匹配验证。本研究共收集838次摆位校正前、后匹配结果,分别记录患者平移摆位误差左右方向X(lateral)、进出方向Y(lngitudinal)、升降方向Z(vertical)、旋转误差俯仰方向RX(pitch)、滚动方向RY(roll)及左右旋转方向RZ(yaw)匹配结果。应用SPSS13.0统计软件,对Hexa PODTMevoRT床校正前后位移误差数据行配对t检验。结果:椎体肿瘤摆位误差(绝对值)中,3个平移X、Y和Z方向摆位误差结果分别为颈椎(1.71±0.10)mm、(1.81±0.11)mm和(1.94±0.09)mm;胸椎(3.17±0.19)mm、(4.26±0.28)mm和(2.18±0.12)mm;腰椎(2.69±0.24)mm、(3.33±0.26)mm和(2.86±0.21)mm。患者摆位后首次CBCT获得摆位误差数据与误差纠正后(动床后)再次CBCT验证后获得残余误差数据3个平移X、Y和Z方向分别为颈椎(0.5±2.4)mm、(0.01±2.4)mm和(2.4±1.4)mm,胸椎(1.17±0.11)mm、(0.26±0.30)mm和(0.08±0.12)mm,腰椎(1.09±0.24)mm、(2.03±1.26)mm和(0.06±0.51)mm。进行配对t检验结果:颈椎及胸椎平移3个方向误差纠正前后差异均有统计学意义;腰椎仅是升降Z方向平移误差纠正前后差异统计学有意义(t=-3.518,P0.001)。3个旋转RX、RY和RZ方向摆位误差分别为颈椎肿瘤0.67°±0.04°、1.06°±0.06°和0.78°±0.05°,胸椎0.62°±0.05°、0.75°±0.06°和0.84°±0.06°,腰椎0.59°±0.06°、0.80°±0.07°和0.73°±0.06°;误差纠正后(动床后)再次CBCT验证后获得残余误差数据3个旋转方向RX、RY和RZ方向分别为颈椎肿瘤0.27°±0.14°、1.20°±0.04°和0.28°±0.05°,胸椎0.02°±0.20°、0.05°±0.26°和0.64°±0.16°,腰椎0.09°±0.26°、0.50°±0.05°和0.03°±0.16°,误差纠正前后颈椎和腰椎旋转3个方向差异均具有统计学意义,胸椎仅是滚动方向RY方向差异有统计学意义(t=7.106,P0.001)。30例患者疼痛均有缓解,未发现放疗副反应。结论:IGRT下Hexa PODTMevoRT床对脊柱肿瘤放射治疗的摆位误差纠正有明显作用,建议采用在线校正脊柱肿瘤放射治疗摆位误差。
[Abstract]:Objective: to study the cervical vertebrae, The 6-DOF positioning error analysis of intensity-modulated radiotherapy for thoracic and lumbar spine tumors under the guidance of cone-beam CT(cone beam CT imaging. Methods: from May 2013 to June 2014, spinal malignancy was performed in the third Hospital of Peking University. 30 patients with tumor radiotherapy, 10 cases of cervical spine tumors, 10 cases of thoracic tumors and 10 cases of lumbar vertebrae tumors were guided by AXESSE linear accelerator (CBCT) of Swedish medical company ELEKTAA. The Hexa PODTMevoRT bed is used for on-line correction of the pendulum error from translation and rotation in six degrees of freedom direction. Ct simulation location is used to obtain the treatment plan reference image (3 mm thickness of 120kV / 200m ASL). Before each treatment, the KV / V level of Hexa PODTMevoRT is scanned with 100kV / 36.6 m / s / s 20 beam field. The CBCT image of collimator is automatically matched by bone window mode and plan reference image. After error correction, CBCT scanning was performed again, and the two images and the planned reference images were matched and verified respectively. In this study, a total of 838 pendulum correction results were collected before and after pendulum correction. The matching results were recorded respectively in the right and left directions of the swinging error, in the direction of entry and exit, in the direction of entrance and exit, in the direction of lifting and descending, in the direction of pitching of rotation error, in the direction of pitching, in the direction of rolling, and in the direction of left and right rotation, respectively. SPSS13.0 statistical software was used. The displacement error data before and after correction of Hexa PODTMevoRT bed were tested by paired t test. Results: of the three lateral displacement errors (absolute values) of vertebral body tumor, the results were 1.71 卤0.10mm 卤1.81 卤0.11)mm and 1.94 卤0.09mm for the cervical vertebrae, 3.17 卤0.19mm and 2.18 卤0.12mm for the thoracic vertebrae, 2.69 卤0.24mm and 3.33 卤0.26)mm for the lumbar vertebrae respectively, and 2.69 卤0.24mm and 3.33 卤0.26)mm for the lumbar vertebrae, respectively. After the first CBCT was obtained and the error corrected (after the moving bed) was again verified by CBCT, the remaining error data were obtained. The three translational error data were obtained in the cervical spine (0.5 卤2.4 mm) and Z direction (0.01 卤2.4 卤1.4 mm), the thoracic vertebrae (1.17 卤0.11 mm) were 0.26 卤0.30)mm and 0.08 卤0.12 mm, the lumbar vertebrae were 1.09 卤0.24 mm, 2.03 卤1.26)mm and 0.06 卤0.51 mm respectively. The results of paired t test showed that there were significant differences between the three direction errors of cervical vertebra and thoracic vertebrae before and after correction. There were significant differences between the lumbar vertebrae before and after correction of the Z direction translation error. The three rotation RXRY and RZ positioning errors were 0.67 掳卤0.04 掳1.06 掳卤0.06 掳and 0.78 掳卤0.05 掳respectively, thoracic vertebrae 0.62 掳卤0.05 掳0.75 掳卤0.06 掳and 0.84 掳卤0.06 掳, lumbar vertebrae 0.59 掳卤0.06 掳0.80 掳卤0.07 掳and 0.73 掳卤0.06 掳respectively. The residual error data obtained by CBCT were: cervical spine tumor 0.27 掳卤0.14 掳1.20 掳卤0.04 掳and RZ direction 0.28 掳卤0.04 掳, thoracic vertebra 0.02 掳卤0.20 掳0.05 掳卤0.26 掳and 0.64 掳卤0.16 掳, lumbar spine 0.09 掳卤0.26 掳0.50 掳卤0.05 掳and 0.03 掳卤0.16 掳respectively. There was significant difference in the direction RY of thoracic vertebrae in rolling direction. The pain was alleviated in all 30 patients, but no side effects of radiotherapy were found. Conclusion the Hexa PODTMevoRT bed has a significant effect on correction of positioning error in radiotherapy of spinal tumors under the condition of 1: IGRT.Conclusion\\\; It is suggested that the alignment error of radiotherapy for spinal tumors should be corrected on line.
【作者单位】：北京大学第三医院肿瘤放射治疗科;
【分类号】：R730.55;R738.1

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