摘要
目的:应用CTVision图像引导放疗(CTVision IGRT)系统中自带k V级CT研究乳腺癌术后患者行乳腺托架联合热塑体模固定在精确放疗中的摆位误差。方法:应用西门子CTVision图像引导直线加速器放疗10例乳腺癌术后患者,采用乳腺托架联合热塑体模固定行CTVision图像引导系统自带大孔径CT扫描。分别在治疗前3天连续做3次及治疗期间每周1次行图像引导。将获得乳腺癌术后患者验证图像与计划图像进行两种不同方式的配准得出摆位误差,并记录骨性手动配准和皮肤标记瘤床区域配准下的摆位误差数据,分析左右(X轴)、上下(Y轴)、前后(Z轴)方向的位移误差的差异。结果:10例乳腺癌术后患者摆位共进行CTVision图像引导系统自带的大孔径CT扫描80次,骨性手动配准和皮肤标记瘤床区域配准在左右方向(X轴)的位移误差分别为(0.07±0.24)cm和(-0.13±0.56)cm,在上下方向(Y轴)的位移误差分别为(0.05±0.26)cm和(-0.03±0.44)cm,在前后方向(Z轴)的位移误差分别为(0.07±0.11)cm和(0.19±0.20)cm。对上述三维方向上的位移误差数值超过5 mm进行重新摆位或在线移动治疗床校正,校正后X、Y、Z轴3个方向上的位移误差均低于纠正前水平。结论:(1)CTVsion图像引导放疗系统自带的大孔径CT扫描图像研究乳腺癌术后患者调强放疗的摆位误差在可接受范围内,骨性手动配准好于皮肤标记瘤床区域的配准,乳腺癌术后患者行调强放疗以骨性手动配准确定摆位误差更符合实际选择;(2)乳腺托架联合热塑体模的固定方式重复性与稳定性良好,摆位失败率低。热塑体模可以有效控制呼吸运动引起在前后方向上的误差。乳腺托架联合热塑体模是乳腺癌术后患者较好的固定方式之一。
Objective To research on the set-up errors of breast bracket combined with thermoplastic immobilization in precise radiotherapy after breast cancer operation by applying the kV CT in CTVision image-guided radiotherapy （CTVision IGRT） system. Methods Siemens CTVision image-guided linear accelerator treatments were respectively carried out for 10 postoperative patients with breast cancer. Breast bracket combined with thermoplastic immobilization was applied to undergo CT scans with large aperture in CTVision IGRT system. Image-guidance was respectively conducted three consecutive times in the three days before the treatment and once a week during the treatment. Set-up errors were obtained by two kinds of registrations for the verified images and planning images of postoperative patients with breast cancer. And set-up errors of osseous manual registration and skin marking tumor bed region registration were recorded. The differences of displacement errors in left-right, head-foot and dorsum-abdomen directions were analyzed. Results Eighty CT scans with large aperture in CTVision IGRT system were carried out for 10 postoperative patients with breast cancer. The displacement errors of osseous manual registration and skin marking tumor bed region registration in left-fight direction were respectively （0.07±0.24） cm and （-0.13±0.56） cm, and those in head-foot directions were respectively （0.05±0.26） cm and （-0.03±0.44） cm, and those in dorsum- abdomen direction were respectively （0.07±0.11） cm and （0.19±0.20） cm. When the displacement errors were more than 5 mm in three directions, patients would be positioned again or the treatment bed would be moved to make the corrected displacement errors in three directions lower than those before correction. Conclusion The set-up errors of radiotherapy studied by CT scans with large aperture in CTVision IGRT system are acceptable. And the osseous manual registration is better than skin marking tumor bed registration, so osseous manual registration should be applied in the intensity-modulated radiotherapy for postoperative patients with breast cancer. Breast bracket combined with thermoplastic immobilization has satisfactory reproducibility and stability, lowering the rate of unsatisfactory positioning. The thermoplastic immobilization can effectively reduce the set-up errors in dorsum-abdomen direction caused by respiratory motion. Breast bracket combined with thermoplastic immobilization is a better fixed way for postoperative patients with breast cancer.
出处
《中国医学物理学杂志》
CSCD
2015年第6期870-873,877,共5页
Chinese Journal of Medical Physics
基金
广东省科技计划项目(2015A020214013)
关键词
图像引导放疗系统
CTVision
乳腺癌
术后
调强放疗
摆位误差
image-guided radiotherapy system
CTVsion
breast cancer
postoperative
intensity-modulated radiotherapy
set- up errors
