Wahl Niklas, Bangert Mark, Kamerling Cornelis P, Ziegenhein Peter, Bol Gijsbert H, Raaymakers Bas W, Oelfke Uwe
German Cancer Research Center - DKFZ.
J Appl Clin Med Phys. 2016 Jul 8;17(4):172-189. doi: 10.1120/jacmp.v17i4.6117.
Conventional treatment planning in intensity-modulated radiation therapy (IMRT) is a trial-and-error process that usually involves tedious tweaking of optimization parameters. Here, we present an algorithm that automates part of this process, in particular the adaptation of voxel-based penalties within normal tissue. Thereby, the proposed algorithm explicitly considers a priori known physical limitations of photon irradiation. The efficacy of the developed algorithm is assessed during treatment planning studies comprising 16 prostate and 5 head and neck cases. We study the eradication of hot spots in the normal tissue, effects on target coverage and target conformity, as well as selected dose volume points for organs at risk. The potential of the proposed method to generate class solutions for the two indications is investigated. Run-times of the algorithms are reported. Physically constrained voxel-based penalty adaptation is an adequate means to automatically detect and eradicate hot-spots during IMRT planning while maintaining target coverage and conformity. Negative effects on organs at risk are comparably small and restricted to lower doses. Using physically constrained voxel-based penalty adaptation, it was possible to improve the generation of class solutions for both indications. Considering the reported run-times of less than 20 s, physically constrained voxel-based penalty adaptation has the potential to reduce the clinical workload during planning and automated treatment plan generation in the long run, facilitating adaptive radiation treatments.
调强放射治疗（IMRT）中的传统治疗计划是一个反复试验的过程，通常需要对优化参数进行繁琐的调整。在此，我们提出一种算法，可自动执行该过程的一部分，特别是在正常组织内基于体素的惩罚调整。由此，所提出的算法明确考虑了光子照射先验已知的物理限制。在包含16例前列腺癌和5例头颈部癌病例的治疗计划研究中评估了所开发算法的有效性。我们研究了正常组织中热点的消除、对靶区覆盖和靶区适形性的影响，以及危及器官的选定剂量体积点。研究了所提出方法为这两种适应症生成类解决方案的潜力。报告了算法的运行时间。基于体素的物理约束惩罚调整是在IMRT计划期间自动检测和消除热点的适当手段，同时保持靶区覆盖和适形性。对危及器官的负面影响相对较小，且仅限于较低剂量。使用基于体素的物理约束惩罚调整，可以改善这两种适应症的类解决方案生成。考虑到报告的运行时间少于20秒，基于体素的物理约束惩罚调整有可能长期减少计划和自动治疗计划生成期间的临床工作量，促进自适应放射治疗。
