Tang Xiaoli, Zagar Timothy M, Bair Eric, Jones Ellen L, Fried David, Zhang Longzhen, Tracton Gregg, Xu Zijie, Leach Traci, Chang Sha, Marks Lawrence B
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Department of Radiation Oncology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina.
Pract Radiat Oncol. 2014 May-Jun;4(3):e151-e158. doi: 10.1016/j.prro.2013.05.004. Epub 2013 Jun 14.
Three-dimensional (3D) surface matching is a novel method to administer deep inspiration breath-hold (DIBH) radiation therapy for left-sided breast cancer to reduce cardiac exposure. We analyzed port (x-ray) films to assess patient setup accuracy and treatment times to assess the practical workflow of this system.
The data from 50 left-sided breast cancer patients treated with DIBH were studied. AlignRT (London, UK) was used. The distance between the field edge and the anterior pericardial shadow as seen on the routine port films (dPORT), and the corresponding distance seen on the digitally reconstructed radiographs (DRR) from the planning (dDRR) were compared as a quantitative measure of setup accuracy. Variations of dPORT - dDRR over the treatment course were assessed. In a subset of 21 patients treated with tangential beams alone, the daily treatment durations were analyzed to assess the practical workflow of this system.
Considering all 50 patients, the mean absolute systematic uncertainty between dPORT and dDRR was 0.20 cm (range, 0 to 1.22 cm), the mean systematic uncertainty was -0.07 cm (range, -1.22 to 0.67 cm), and their mean random uncertainty was 0.19 cm (range, 0 to 0.84 cm). There was no significant change in dPORT - dDRR during the course of treatment. The mean patient treatment duration for the 21 patients studied was 11 minutes 48 seconds. On intrapatient assessments, 15/21 had nonsignificant trends toward reduced treatment durations during their course of therapy. On interpatient comparisons, the mean treatment times declined as we gained more experience with this technique.
The DIBH patient setup appears to provide a fairly reproducible degree of cardiac sparing with random uncertainties of ≈ 0.2 cm. The treatment durations are clinically acceptable and appear not to change significantly over time on an intrapatient basis, and to improve over time on an interpatient basis.
三维（3D）表面匹配是一种用于左侧乳腺癌深吸气屏气（DIBH）放射治疗以减少心脏受照剂量的新方法。我们分析了射野（X线）片以评估患者摆位精度，并分析了治疗时间以评估该系统的实际工作流程。
研究了50例接受DIBH治疗的左侧乳腺癌患者的数据。使用了AlignRT（英国伦敦）。将常规射野片上所见的射野边缘与心包前界阴影之间的距离（dPORT），与计划数字重建X线片（DRR）上相应的距离（dDRR）进行比较，作为摆位精度的定量指标。评估了整个治疗过程中dPORT - dDRR的变化。在仅接受切线野照射的21例患者亚组中，分析了每日治疗时长以评估该系统的实际工作流程。
考虑全部50例患者，dPORT与dDRR之间的平均绝对系统不确定性为0.20 cm（范围为0至1.22 cm），平均系统不确定性为 -0.07 cm（范围为 -1.22至0.67 cm），平均随机不确定性为0.19 cm（范围为0至0.84 cm）。在治疗过程中，dPORT - dDRR无显著变化。所研究的21例患者的平均治疗时长为11分48秒。在患者内评估中，15/21例患者在治疗过程中治疗时长有缩短的非显著趋势。在患者间比较中，随着我们对该技术经验的增加，平均治疗时间有所下降。
DIBH患者摆位似乎能提供相当可重复的心脏保护程度，随机不确定性约为0.2 cm。治疗时长在临床上是可接受的，在患者内随时间似乎无显著变化，在患者间随时间有所改善。
