Nesvacil Nicole, Schmid Maximilian P, Pötter Richard, Kronreif Gernot, Kirisits Christian
Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Austria.
Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
Brachytherapy. 2016 Nov-Dec;15(6):839-844. doi: 10.1016/j.brachy.2016.08.009. Epub 2016 Sep 29.
To investigate the feasibility of a treatment planning workflow for three-dimensional image-guided cervix cancer brachytherapy, combining volumetric transrectal ultrasound (TRUS) for target definition with CT for dose optimization to organs at risk (OARs), for settings with no access to MRI.
A workflow for TRUS/CT-based volumetric treatment planning was developed, based on a customized system including ultrasound probe, stepper unit, and software for image volume acquisition. A full TRUS/CT-based workflow was simulated in a clinical case and compared with MR- or CT-only delineation. High-risk clinical target volume was delineated on TRUS, and OARs were delineated on CT. Manually defined tandem/ring applicator positions on TRUS and CT were used as a reference for rigid registration of the image volumes. Treatment plan optimization for TRUS target and CT organ volumes was performed and compared to MRI and CT target contours.
TRUS/CT-based contouring, applicator reconstruction, image fusion, and treatment planning were feasible, and the full workflow could be successfully demonstrated. The TRUS/CT plan fulfilled all clinical planning aims. Dose-volume histogram evaluation of the TRUS/CT-optimized plan (high-risk clinical target volume D, OARs D for) on different image modalities showed good agreement between dose values reported for TRUS/CT and MRI-only reference contours and large deviations for CT-only target parameters.
A TRUS/CT-based workflow for full three-dimensional image-guided cervix brachytherapy treatment planning seems feasible and may be clinically comparable to MRI-based treatment planning. Further development to solve challenges with applicator definition in the TRUS volume is required before systematic applicability of this workflow.
探讨一种三维图像引导宫颈癌近距离治疗计划工作流程的可行性，该流程将用于靶区定义的容积式经直肠超声（TRUS）与用于危及器官（OARs）剂量优化的CT相结合，适用于无法进行MRI检查的情况。
基于一个定制系统开发了基于TRUS/CT的容积式治疗计划工作流程，该系统包括超声探头、步进单元和用于图像容积采集的软件。在一个临床病例中模拟了完整的基于TRUS/CT的工作流程，并与仅使用MR或CT的勾画进行比较。在TRUS上勾画高危临床靶区容积，在CT上勾画OARs。在TRUS和CT上手动定义的串联/环形施源器位置用作图像容积刚性配准的参考。对TRUS靶区和CT器官容积进行治疗计划优化，并与MRI和CT靶区轮廓进行比较。
基于TRUS/CT的轮廓勾画、施源器重建、图像融合和治疗计划是可行的，并且可以成功展示完整的工作流程。TRUS/CT计划满足了所有临床计划目标。在不同图像模态下对TRUS/CT优化计划（高危临床靶区容积D、OARs D）的剂量体积直方图评估显示，TRUS/CT和仅MRI参考轮廓报告的剂量值之间具有良好的一致性，而仅CT靶区参数存在较大偏差。
基于TRUS/CT的完整三维图像引导宫颈癌近距离治疗计划工作流程似乎是可行的，并且在临床上可能与基于MRI的治疗计划相当。在该工作流程系统应用之前，需要进一步改进以解决TRUS容积中施源器定义的挑战。
