锥形束CT引导全乳调强放疗摆位误差自适应的预测与校正
目的基于锥形束CT(CBCT)建立乳腺癌保乳术后全乳调强放疗(IMRT)疗程中患者分次间摆位位移的变化模型,探讨连续CBCT校正所得摆位误差应用于后续疗程的可行性。方法选择保乳术后行全乳IMRT的18例患者,放疗计划实施前采集CBCT图像,将重建好的CBCT图像与计划CT图像行像素一解剖结构密度配准,记录左右、前后和头脚方向上的位移。实施在线校正后再次采集CBCT图像,获取校正后三维方向上的位移。当CBCT扫描次数达到5次后,随CBCT扫描次数的增加,依据每位患者放疗疗程中获取的位移值分别计算基于连续多次CBCT在线配准(≥5次)获取的系统误差和随机误差,分析随治疗次数的增加患者摆位边界的变化...
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Published in | 中华肿瘤杂志 Vol. 38; no. 3; pp. 197 - 201 |
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Main Author | |
Format | Journal Article |
Language | Chinese |
Published |
山东省肿瘤医院放疗科,济南,250117
2016
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Subjects | |
Online Access | Get full text |
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Summary: | 目的基于锥形束CT(CBCT)建立乳腺癌保乳术后全乳调强放疗(IMRT)疗程中患者分次间摆位位移的变化模型,探讨连续CBCT校正所得摆位误差应用于后续疗程的可行性。方法选择保乳术后行全乳IMRT的18例患者,放疗计划实施前采集CBCT图像,将重建好的CBCT图像与计划CT图像行像素一解剖结构密度配准,记录左右、前后和头脚方向上的位移。实施在线校正后再次采集CBCT图像,获取校正后三维方向上的位移。当CBCT扫描次数达到5次后,随CBCT扫描次数的增加,依据每位患者放疗疗程中获取的位移值分别计算基于连续多次CBCT在线配准(≥5次)获取的系统误差和随机误差,分析随治疗次数的增加患者摆位边界的变化趋势。结果CBCT在线校正前系统误差变化幅度〈1mm,但随着CBCT扫描次数的增加(10次之后),前后方向系统误差变大,而三维方向随机误差在CBCT扫描7次后较前均略有增加。CBCT在线校正后放疗前20次系统误差趋势稳定接近于0,但20次之后前后和头脚方向略有增加(幅度变化〈0.5mm),而三维方向随机误差在放疗20次后均变小。在线校正前后,连续5、8、11、14次在线配准间获取的三维方向系统误差和随机误差及摆位误差的差异均无统计学意义(均P〉0.05)。结论保乳术后IMRT整个疗程中摆位误差是相对稳定的,前期连续5次CBCT扫描作为摆位误差校正频次及适应性治疗计划循变修改时机和频次较为合适。 |
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Bibliography: | Wang Wei, Li Jianbin, Xu Min, Shao Qian, Fan Tingyong, Zhang Yingjie, Xing Jun, Hu Hongguang(Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan 250117, China) 11-2152/R Objective To quantify the setup error (SE) in breast cancer patients treated with intensity modulated radiotherapy (IMRT) based on cone beam CT (CBCT), and to explore the feasibility of using several CBCT scans to presume and correct SE in the treatment for breast cancer patients. Methods Eighteen breast cancer patients after breast conserving surgery who underwent whole breast IMRT were included in this study. Three dimensional interfraction motion before and after on-line CBCT-based corrections were quantified. The on-line CBCT-based corrections were performed using automated greyscale match. The system SE (∑) and random error (or) were calculated for each patient based on the consecutive multiple online scanning based on CBCT (≥5). The trends in magnitudes of ∑ and cr were assessed during the treatment. Results Th |
ISSN: | 0253-3766 |
DOI: | 10.3760/cma.j.issn.0253-3766.2016.03.007 |