Biophysics Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
Radiotherapy Department, Baheya Hospital, Giza, Egypt.
Radiat Environ Biophys. 2024 Aug;63(3):423-431. doi: 10.1007/s00411-024-01078-z. Epub 2024 Jul 6.
This retrospective study was performed to evaluate plan quality and treatment delivery parameters of stereotactic body radiation therapy (SBRT) for prostate cancer. The study utilized different isocentric modulated techniques: intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) using 6 MV flattening filter (FF) and 10 MV flattening filter-free beams (FFF). Fifteen retrospective prostate cancer patients were selected for this study. Sixty plans were created with an SBRT-prescribed dose of 36.25 Gy delivered in five fractions. Planning target volume (PTV) coverage, plan quality indices, doses delivered to organs at risk (OARs), and treatment delivery parameters were compared for all plans. It turned out that VMAT plans, particularly those using the FFF beam, provided superior target conformality and a steeper dose gradient as compared to IMRT plans. Additionally, VMAT plans showed better OARs sparing compared to IMRT plans. However, IMRT plans delivered a lower maximum dose to the target than VMAT plans. Importantly, the VMAT plans resulted in reduced treatment delivery parameters, including beam on time (BOT), monitor unit (MU), and modulation factor (MF), compared to IMRT plans. Furthermore, a statistically significant difference was observed in BOT and mean body dose between FF and FFF beams, with FFF beams showing superior performance. Considering all results, VMAT using 10 MV (FFF) is suggested for treating prostate cancer patients with SBRT. This offers the fastest delivery in addition to maintaining the highest plan quality.
本回顾性研究旨在评估前列腺癌立体定向体放射治疗（SBRT）的计划质量和治疗交付参数。该研究使用了不同的等中心调制技术：强度调制放疗（IMRT）和容积调制弧形治疗（VMAT），使用 6 MV 均整滤波器（FF）和 10 MV 无均整滤波器（FFF）。本研究选择了 15 名回顾性前列腺癌患者。共创建了 60 个计划，采用 SBRT 规定剂量 36.25Gy，分 5 次给予。比较了所有计划的计划靶区（PTV）覆盖、计划质量指数、危及器官（OAR）的剂量分布和治疗交付参数。结果表明，与 IMRT 计划相比，VMAT 计划，特别是使用 FFF 束的计划，提供了更好的靶区适形性和更陡峭的剂量梯度。此外，VMAT 计划与 IMRT 计划相比，对 OAR 的保护更好。然而，IMRT 计划给予靶区的最大剂量低于 VMAT 计划。重要的是，与 IMRT 计划相比，VMAT 计划的治疗交付参数，包括束开启时间（BOT）、监视器单位（MU）和调制因子（MF）降低。此外，FF 和 FFF 束之间在 BOT 和平均体剂量方面观察到了统计学上的显著差异，FF 束表现出更好的性能。考虑到所有结果，建议使用 10 MV（FFF）的 VMAT 治疗 SBRT 的前列腺癌患者。这提供了最快的交付速度，同时保持了最高的计划质量。
