Icon Group, 22 Cordelia Street, South Brisbane Qld 4101, Australia.
School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, GPO Box 2434, Brisbane Qld 4000, Australia.
Biomed Phys Eng Express. 2021 Jul 23;7(5). doi: 10.1088/2057-1976/ac14d2.
. This study explored a novel technique to improve the MV imaging based fiducial visibility for a cohort of prostate radiotherapy patients, without compromising the original treatment plan. The study also compared these results to visibility using single MLC control points, as well as short arcs.. Geometric data from 68 prostate radiotherapy treatments, each with implanted gold fiducials, was retrospectively analysed. Fiducials were contoured for each patient, and conventional and SBRT treatment plans were generated using a VMAT technique. Using an in-house script, fiducial contours were projected onto the VMAT MLC control points. Resulting data was assessed to determine whether the fiducial contours were theoretically visible for single MLC control points and groups of MLC control points (short arcs), both being surrogates for intra-fraction MV imaging. Using this data, a theoretical quadrant technique was investigated that assessed the region surrounding each fiducial to determine if visualisation would theoretically improve.. Using a conventional treatment type, mean fiducial visibility for single MLC control points across the patient cohort ranged from 2.5% up to 17.8%. For SBRT, fiducial visibility ranged from 1.8% up to 19.7%. For short arcs, fiducial visibility for conventional treatment types ranged from 5.9% up to 20.7%. For SBRT, fiducial visibility ranged from 4.6% up to 23.1%. When the novel fiducial quadrant technique was used, theoretical visibility improved two-fold, from 22.7% up to 52.5% and from 24.7% up to 55.3% for conventional and SBRT treatment types respectively.. Fiducial visibility was assessed for a cohort of VMAT prostate patients. Using the novel quadrant technique, it was demonstrated that theoretical visualisation and localisation of the implanted fiducials could be improved two-fold, without sacrificing treatment plan quality.
. 本研究探索了一种新颖的技术，以提高前列腺放射治疗患者队列的 MV 成像基准点可视性，同时不影响原始治疗计划。该研究还将这些结果与使用单个 MLC 控制点以及短弧的可视性进行了比较。. 回顾性分析了 68 例前列腺放射治疗患者的几何数据，每个患者均植入了金基准点。为每位患者勾画基准点，并使用 VMAT 技术生成常规和 SBRT 治疗计划。使用内部脚本，将基准点轮廓投影到 VMAT MLC 控制点上。评估所得数据，以确定基准点轮廓理论上是否可用于单个 MLC 控制点和 MLC 控制点组（短弧），这两者均为 MV 成像的内部分割替代物。使用此数据，研究了一种理论上的象限技术，该技术评估了每个基准点周围的区域，以确定理论上是否可以改善可视化效果。. 使用常规治疗类型，整个患者队列中单一点 MLC 控制点的平均基准点可视性范围为 2.5%至 17.8%。对于 SBRT，基准点可视性范围为 1.8%至 19.7%。对于短弧，常规治疗类型的基准点可视性范围为 5.9%至 20.7%。对于 SBRT，基准点可视性范围为 4.6%至 23.1%。当使用新颖的基准点象限技术时，理论可视性提高了两倍，常规和 SBRT 治疗类型分别从 22.7%提高到 52.5%和从 24.7%提高到 55.3%。. 对一组 VMAT 前列腺患者进行了基准点可视性评估。使用新颖的象限技术，证明可以在不牺牲治疗计划质量的前提下，将植入基准点的理论可视化和定位提高两倍。
