Role of beam orientation optimization in intensity-modulated radiation therapy
Role of beam orientation optimization in intensity-modulated radiation therapy
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DOI：
10.1016/s0360-3016(01)01502-4
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发表时间：
2001-06-01
影响因子：
7
通讯作者：
Xing, L
中科院分区：
文献类型：
--
作者：
Pugachev, A;Li, JG;Xing, L
目的：为了研究调强放射治疗（IMRT）中的波束方向优化的作用，并研究非共面调强beams.Methods和Materials的潜在好处：实施了一种波束方向优化算法。为此，将系统变量分为两组：射束位置（机架和扫描床角度）和射束轮廓（小射束权重）。采用模拟退火算法对射束方向进行优化，采用同步迭代逆治疗计划算法（SIITP）对射束强度分布进行优化。三个临床病例进行了研究：局限性前列腺癌，鼻咽癌，脊柱旁肿瘤。9个字段用于所有治疗。对于每种情况，进行3种类型的治疗计划优化：（1）针对9个等角间隔共面光束优化光束强度分布;（2）针对9个共面光束优化方向和强度分布;（3）针对9个非共面光束优化方向和强度分布。对于局限性前列腺情况，上述所有3种类型的优化导致类似质量的剂量分布。对于鼻咽部的情况下，优化的非共面光束提供了一个显着的增益在总肿瘤体积覆盖。对于脊柱旁病例，使用非共面射束的方向优化可以更好地保留肾脏并改善总肿瘤体积覆盖范围。结论：IMRT治疗计划对射束方向选择的敏感性因部位而异。在某些情况下，即使射束数量高达9个，射束方向的选择也很重要。非共面射束为IMRT治疗优化提供了额外的自由度，并可显著改善某些复杂计划的质量。(C)2001 Elsevier Science Inc.
Purpose: To investigate the role of beam orientation optimization in intensity-modulated radiation therapy (IMRT) and to examine the potential benefits of noncoplanar intensity-modulated beams.Methods and Materials: A beam orientation optimization algorithm was implemented. For this purpose, system variables were divided into two groups: beam position (gantry and table angles) and beam profile (beamlet weights). Simulated annealing was used for beam orientation optimization and the simultaneous iterative inverse treatment planning algorithm (SIITP) for beam intensity profile optimization. Three clinical cases were studied: a localized prostate cancer, a nasopharyngeal cancer, and a paraspinal tumor. Nine fields were used for all treatments. For each case, 3 types of treatment plan optimization were performed: (1) beam intensity profiles were optimized for 9 equiangular spaced coplanar beams; (2) orientations and intensity profiles were optimized for 9 coplanar beams; (3) orientations and intensity profiles were optimized for 9 noncoplanar beams.Results: For the localized prostate case, all 3 types of optimization described above resulted in dose distributions of a similar quality. For the nasopharynx case, optimized noncoplanar beams provided a significant gain in the gross tumor volume coverage. For the paraspinal case, orientation optimization using noncoplanar beams resulted in better kidney sparing and improved gross tumor volume coverage.Conclusion: The sensitivity of an IMRT treatment plan with respect to the selection of beam orientations varies from site to site. For some cases, the choice of beam orientations is important even when the number of beams is as large as 9, Noncoplanar beams provide an additional degree of freedom for IMRT treatment optimization and may allow for notable improvement in the quality of some complicated plans. (C) 2001 Elsevier Science Inc.