Clinical evaluation of direct aperture optimization when applied to head-and-neck IMRT
Clinical evaluation of direct aperture optimization when applied to head-and-neck IMRT
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DOI：
10.1016/j.meddos.2007.04.002
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发表时间：
2008-03-01
影响因子：
1.2
通讯作者：
Williams, Matthew
中科院分区：
文献类型：
--
作者：
Jones, Stephen;Williams, Matthew
直接机器参数优化（DMPO）是作为Pinnacle计划系统（Philips Radiation Oncology Systems，Milpitas，CA）的可选项目发布的叶分割程序;它基于直接孔径优化的原理，其中优化单个段的尺寸、形状和重量以产生调强放射治疗（IMRT）计划。在这项研究中，我们比较DMPO的传统方法的调强放射治疗计划，其中强度图进行优化之前，转换成可交付的多叶准直器（MLC）孔径，我们确定是否有任何剂量的改善，治疗效率的增益，或计划的优势提供了使用DMPO。11例接受调强放射治疗的头颈部患者使用每种优化方法生成治疗计划。对于每例患者，每种优化方法使用相同的计划参数。使用Pinnacle 7.6c版软件进行所有计算，并使用配备120叶Millennium MLC（Varian Medical Systems，Palo Alto，CA）的Varian 2100 EX直线加速器上的步进式IMRT方法进行治疗。根据计算时间、符合性指数、优化中使用的复合目标值、节段数、监测单位（MU）和治疗时间对每个计划进行评估。结果表明，DMPO在各方面都上级传统的优化方法。相当大的优势被观察到在剂量质量的DMPO计划，这也需要减少32%的时间来计算，42%的MU，和35%的节段比传统的优化方法。这些减少直接转化为治疗时间减少29%。虽然在计划和治疗效率方面观察到了相当大的收益，但它们是我们机构特有的，直接孔径优化对计划质量和工作流程的影响将取决于特定机构使用的计划参数、计划系统和直线加速器。(c)2008年美国医学剂量学家协会。
Direct Machine Parameter Optimization (DMPO) is a leaf segmentation program released as an optional item of the Pinnacle planning system (Philips Radiation Oncology Systems, Milpitas, CA); it is based on the principles of direct aperture optimization where the size, shape, and weight of individual segments are optimized to produce an intensity modulated radiation treatment (IMRT) plan. In this study, we compare DMPO to the traditional method of IMRT planning, in which intensity maps are optimized prior to conversion into deliverable multileaf collimator (MLC) apertures, and we determine if there was any dosimetric improvement, treatment efficiency gain, or planning advantage provided by the use of DMPO. Eleven head-and-neck patients treated with IMRT had treatment plans generated using each optimization method. For each patient, the same planning parameters were used for each optimization method. All calculations were performed using Pinnacle version 7.6c software and treatments were delivered using a step-and-shoot IMRT method on a Varian 2100EX linear accelerator equipped with a 120-leaf Millennium MLC (Varian Medical Systems, Palo Alto, CA). Each plan was assessed based on the calculation time, a conformity index, the composite objective value used in the optimization, the number of segments, monitor units (MUs), and treatment time. The results showed DMPO to be superior to the traditional optimization method in all areas. Considerable advantages were observed in the dosimetric quality of DMPO plans, which also required 32% less time to calculate, 42% fewer MUs, and 35% fewer segments than the conventional optimization method. These reductions translated directly into a 29% decrease in treatment times. While considerable gains were observed in planning and treatment efficiency, they were specific to our institution, and the impact of direct aperture optimization on plan quality and workflow will be dependent on the planning parameters, planning system, and linear accelerators used by a particular institution. (c) 2008 American Association of Medical Dosimetrists.