Smoothing intensity-modulated treatment delivery under hardware constraints

被引:19
作者
Ma, LJ [1 ]
机构
[1] Univ Maryland, Sch Med, Dept Radiat Oncol, Baltimore, MD 21201 USA
关键词
intensity modulation; radiotherapy; treatment planning; multileaf collimator; leaf-sequencing;
D O I
10.1118/1.1521121
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
A method is developed to smooth intensity-modulated beam delivery while considering hardware constraints. The method uses matrix algebra to model MLC leaf motion and hardware constraints such as interleaf digitization, synchronization requirements, and intersegment field abutment to deliver intensity modulated beam sequences. It was implemented and demonstrated for simulated and clinical intensity modulated cases. The simulated cases included intensity distributions from 3x3 to 30x30 in dimension with 1000 intensity levels. The clinical examples included four treatments sites: prostate, head and neck, lung, and esophagus cancers. In particular, we studied the relationships between the intensity levels, segment numbers and their influence on the dose-volume histograms of the inversely optimized IMRT treatment plans. It was found that a significant reduction in the leaf segment numbers was achieved by applying the smoothing approach. The effects were found to be more significant for the unconstrained delivery than for the constrained delivery. The effects were also found to be more sensitive for the complex intensity distributions such as the head-and-neck cases than for the less complex ones such as the prostate cases. These results demonstrated the feasibility of maintaining inversely optimized treatment plans under acceptable tolerance levels while smoothing IMRT treatments with hardware constraints. (C) 2002 American Association of Physicists in Medicine.
引用
收藏
页码:2937 / 2945
页数:9
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