Algorithms and functionality of an intensity modulated radiotherapy optimization system
Algorithms and functionality of an intensity modulated radiotherapy optimization system
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DOI：
10.1118/1.598932
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发表时间：
2000-04-01
期刊：
影响因子：
3.8
通讯作者：
Mohan, R
中科院分区：
文献类型：
--
作者：
Wu, QW;Mohan, R
本文的主要目的是描述调强放射治疗(IMRT)优化系统的形式、算法和某些独特功能。该系统与商业治疗计划系统相耦合，该系统具有基于内核叠加算法的精确剂量计算引擎。该系统专为研究和常规临床实践而设计。它采用基于剂量和剂量体积的目标函数。该系统可以同时优化多个靶区的调强放射治疗计划。可以为每个目标体积分配不同的处方剂量，并限制剂量不足或过量，或两者兼而有之。对于有风险的器官，可以应用一种以上的限制。这一功能允许同时治疗原发、区域性疾病和选择性治疗的结节。该系统允许指定对解剖结构的逻辑组合的约束，例如，前列腺计划目标体积和直肠之间的重叠区域或不包括肿瘤的肺的体积。优化也可以在计划上执行，该计划除了强度调制射束之外，还包括其他形式，例如非调强放射治疗的光子和电子束以及近距离治疗源。通过一个体模实例和两个临床实例说明了该系统的各种特征：一个脑立体定向放射外科病例和一个鼻咽部病例。在圆柱体模的例子中，演示了该系统对重叠区域的使用。脑立体定向放射外科的实例显示了调强放射治疗计划相对于传统的基于弧线的计划和具有多个固定门架角度的三维适形计划的改进，并展示了我们的系统在小网格尺寸重要的情况下的应用。鼻咽部的例子显示了调强放射治疗同时治疗大野和增强野的潜力。它还说明了调强放射治疗在高度复杂的情况下保护正常解剖结构的能力，以及通过调强放射治疗在计划和交付方面的效率。在太阳超声公司的工作站上，调强放射治疗的总体计划时间通常不到2小时，其中大部分时间用于重复计算剂量分布。(C)2000年美国医学物理学家协会。
The main purpose of this paper is to describe formalisms, algorithms, and certain unique features of a system for optimization of intensity modulated radiotherapy (IMRT). The system is coupled to a commercial treatment planning system with an accurate dose calculation engine based on the kernel superposition algorithm. The system was designed for use for research as well as for routine clinical practice. It employs dose- and dose-volume-based objective functions. The system can optimize IMRT plans with multiple target volumes simultaneously. Each target volume may be assigned a different prescription dose with constraints on either underdosing, or overdosing, or both. For organs at risk more than one constraint may be applied. This feature allows simultaneous treatment of primary, regional disease and electively treated nodes. The system allows specification of constraints on logical combinations of anatomic structures, such as a. region of overlap between the prostate planning target volume and rectum or the volume of lung excluding the tumor. The optimization may also be performed on plans which, in addition to intensity-modulated beams, include other modalities such as non-IMRT photon and electron beams and brachytherapy sources. The various features of the system are illustrated with one phantom example and two clinical examples: a brain stereotactic radiosurgery case and a nasopharynx case. In the cylindrical phantom example, the use of the system for overlap regions is demonstrated. The brain stereotactic radiosurgery example shows the improvement of IMRT plans over the conventional arcs based plan and the three-dimensional conformal plan with multiple fixed gantry angles and demonstrates the application of our system to cases where small grid sizes are important. The nasopharynx example shows the potential of IMRT to simultaneously treat large and boost fields. It also illustrates the power of IMRT to protect normal anatomic structures for highly complex situations and the efficiency in planning and delivery achievable with IMRT. The overall IMRT planning time is typically less than 2 h on a Sun Ultrasparc workstation, most of which is spent in repeated computation of dose distributions. (C) 2000 American Association of Physicists in Medicine.