Kamath Srijit, Sahni Sartaj, Palta Jatinder, Ranka Sanjay
Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL, USA.
Phys Med Biol. 2004 Jan 7;49(1):33-54. doi: 10.1088/0031-9155/49/1/003.
Dynamic multileaf collimator (DMLC) intensity modulated radiation therapy (IMRT) is used to deliver intensity modulated beams using a multileaf collimator (MLC), with the leaves in motion. DMLC-IMRT requires the conversion of a radiation intensity map into a leaf sequence file that controls the movement of the MLC while the beam is on. It is imperative that the intensity map delivered using the leaf sequence file be as close as possible to the intensity map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf-sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf-sequencing algorithms for dynamic multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under the most common leaf movement constraints that include leaf interdigitation constraint. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bi-directional movement of the MLC leaves.
动态多叶准直器（DMLC）调强放射治疗（IMRT）通过运动的多叶准直器（MLC）来输出调强射束。DMLC-IMRT需要将辐射强度图转换为叶序列文件，该文件在射束开启时控制MLC的运动。至关重要的是，使用叶序列文件输出的强度图要尽可能接近剂量优化算法生成的强度图，同时满足传输系统的硬件限制。叶序列算法的优化是近期多项研究的主题。在这项工作中，我们对动态多叶准直器射束传输的叶序列算法优化进行了系统研究，并在包括叶片交叉约束在内的最常见叶片运动限制条件下，就监测单位（MU）效率给出了优化叶序列设置的严格数学证明。我们的分析表明，基于MLC叶片单向运动的叶序列与MLC叶片双向运动的MU效率相同。
