Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts, USA.
Int J Radiat Oncol Biol Phys. 2012 Dec 1;84(5):e663-8. doi: 10.1016/j.ijrobp.2012.07.2379. Epub 2012 Sep 11.
Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A surface imaging technique was developed for accurate patient setup and reproducible real-time BH positioning.
Three-dimensional surface images were obtained for 20 patients. Surface imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify surface placement during BH. The radiation beam was not turned on if the BH position difference was greater than 5 mm. Real-time surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated.
The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm.
Daily real-time surface imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.
屏气（BH）治疗可用于减少左侧乳腺癌和心脏解剖结构不良患者的心脏剂量。已经开发出一种表面成像技术，用于准确的患者设置和可重复的实时 BH 定位。
对 20 名患者进行了三维表面图像采集。使用表面成像来校正每位患者的日常设置。记录了 443 个分次的初始设置数据，并对其进行了分析，以评估随机和系统误差。实时监测用于验证 BH 期间的表面放置。如果 BH 位置差异大于 5 毫米，则不开设辐射束。对 2398 次 BH 和 363 个治疗分次进行了实时表面数据分析。计算了平均值和最大值差异。计算了大于公差的 BH 百分比。
初始患者设置的平均移位分别为垂直方向 2.0 毫米、纵向 1.2 毫米和横向 0.3 毫米。三维矢量平均移位为 7.8 毫米。随机和系统误差小于 4 毫米。实时表面监测数据表明，22%的 BH 在 5 毫米公差范围内（范围为 7%-41%），并且与乳房体积有关。治疗和参考 BH 位置之间的平均差异在每个方向上均为 2 毫米。对于超出公差的 BH，BH 位置的平均差异为 6.3 毫米，平均最大差异为 8.8 毫米。
每日实时表面成像可确保心脏解剖结构不良的左侧乳腺癌患者 BH 治疗的准确和可重复定位。
