Efficient IMRT inverse planning with a new L1-solver: template for first-order conic solver.
Efficient IMRT inverse planning with a new L1-solver: template for first-order conic solver.
复制标题
使用新的 L1 求解器进行高效 IMRT 逆规划：一阶圆锥求解器的模板。
DOI：
10.1088/0031-9155/57/13/4139
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发表时间：
2012
影响因子：
3.5
通讯作者：
Li,Ruijiang
中科院分区：
文献类型：
--
作者：
Kim,Hojin;Suh,Tae-Suk;Lee,Rena;Xing,Lei;Li,Ruijiang
采用全变分（TV）正则化的调强放射治疗（IMRT）逆计划已被提出来降低注量图的复杂性并促进剂量递送。传统的L-1范数优化问题采用二次规划求解，由于需要二阶牛顿更新，计算时间和内存开销较大。本研究提出了一种新的算法，模板一阶圆锥解算器（TFOCS），快速和内存有效的优化调强放射治疗逆向规划。TFOCS利用双变量更新和一阶方法进行TV最小化，而无需计算和存储QP技术中牛顿更新所需的放大Hessian矩阵。为了评估所提出的方法的有效性和效率，两个临床病例用于IMRT逆向计划：头颈部病例和前列腺病例。为了比较，采用传统的基于QP的TV形式的方法来解决上述两种情况下的注量图优化问题。选择收敛标准和算法参数以实现相似的剂量符合性，从而在两种方法之间进行公平比较。与传统的基于QP的方法相比，所提出的基于TFOCS的方法在保持适形剂量分布的同时，在注量图优化的计算效率上显示出显著的提高。与基于QP的算法相比，使用TFOCS进行注量优化的计算速度增加了4到6倍，同时存储器需求减少了3到4倍。因此，TFOCS为IMRT逆向计划提供了一种有效、快速、节省内存的方法。该方法的独特功能在涉及大量射束的逆向计划中特别重要，例如在VMAT和密集角度采样和稀疏强度调制放射治疗（DASSIM-RT）中。
Intensity modulated radiation therapy (IMRT) inverse planning using total-variation (TV) regularization has been proposed to reduce the complexity of fluence maps and facilitate dose delivery. Conventionally, the optimization problem with L-1 norm is solved with quadratic programming (QP), which is time consuming and memory expensive due to the second-order Newton update. This study proposes to use a new algorithm, template for first-order conic solver (TFOCS), for fast and memory-efficient optimization in IMRT inverse planning. The TFOCS utilizes dual-variable updates and first-order approaches for TV minimization without the need to compute and store the enlarged Hessian matrix required for Newton update in the QP technique. To evaluate the effectiveness and efficiency of the proposed method, two clinical cases were used for IMRT inverse planning: a head and neck case and a prostate case. For comparison, the conventional QP-based method for the TV form was adopted to solve the fluence map optimization problem in the above two cases. The convergence criteria and algorithm parameters were selected to achieve similar dose conformity for a fair comparison between the two methods. Compared with conventional QP-based approach, the proposed TFOCS-based method shows a remarkable improvement in computational efficiency for fluence map optimization, while maintaining the conformal dose distribution. Compared with QP-based algorithms, the computational speed using TFOCS for fluence optimization is increased by a factor of 4 to 6, and at the same time the memory requirement is reduced by a factor of 3 to 4. Therefore, TFOCS provides an effective, fast and memory-efficient method for IMRT inverse planning. The unique features of the approach should be particularly important in inverse planning involving a large number of beams, such as in VMAT and dense angularly sampled and sparse intensity modulated radiation therapy (DASSIM-RT).