Department of Radiation Oncology, Duke University Medical Centre, Durham, NC, USA.
Phys Med Biol. 2011 Mar 7;56(5):1243-58. doi: 10.1088/0031-9155/56/5/002. Epub 2011 Feb 1.
In prostate radiation therapy, inter-fractional organ motion/deformation has posed significant challenges on reliable daily dose delivery. To correct for this issue, off-line re-optimization and online re-positioning have been used clinically. In this paper, we propose an adaptive images guided radiation therapy (AIGRT) scheme that combines these two correction methods in an anatomy-driven fashion. The AIGRT process first tries to find a best plan for the daily target from a plan pool, which consists of the original CT plan and all previous re-optimized plans. If successful, the selected plan is used for daily treatment with translational shifts. Otherwise, the AIGRT invokes the re-optimization process of the CT plan for the anatomy of the day, which is afterward added to the plan pool as a candidate for future fractions. The AIGRT scheme is evaluated by comparisons with daily re-optimization and online re-positioning techniques based on daily target coverage, organs at risk (OAR) sparing and implementation efficiency. Simulated treatment courses for 18 patients with re-optimization alone, re-positioning alone and AIGRT shows that AIGRT offers reliable daily target coverage that is highly comparable to daily re-optimization and significantly improves from re-positioning. AIGRT is also seen to provide improved OAR sparing compared to re-positioning. Apart from dosimetric benefits, AIGRT in addition offers an efficient scheme to integrate re-optimization to current re-positioning-based IGRT workflow.
在前列腺放射治疗中，分次间器官运动/变形对可靠的每日剂量输送带来了重大挑战。为了解决这个问题，已经在临床上使用了离线重新优化和在线重新定位。在本文中，我们提出了一种自适应图像引导放射治疗（AIGRT）方案，该方案以解剖结构为驱动，将这两种校正方法结合在一起。AIGRT 过程首先尝试从计划库中为每日靶区找到最佳计划，该计划库包括原始 CT 计划和所有以前的重新优化计划。如果成功，所选计划将用于每日治疗，进行平移移位。否则，AIGRT 将调用当天解剖结构的 CT 计划的重新优化过程，然后将其作为未来分次的候选计划添加到计划库中。通过与每日重新优化和在线重新定位技术相比，对 AIGRT 方案进行了评估，比较的方面包括每日靶区覆盖率、危及器官（OAR）保护和实施效率。对单独使用重新优化、单独使用重新定位和 AIGRT 的 18 名患者的模拟治疗过程进行了评估，结果表明，AIGRT 提供了可靠的每日靶区覆盖率，与每日重新优化高度可比，并且显著优于重新定位。与重新定位相比，AIGRT 还显示出了对 OAR 保护的改善。除了剂量学方面的益处，AIGRT 还提供了一种有效的方案，可以将重新优化整合到当前基于重新定位的 IGRT 工作流程中。
