Radiation Oncology Department, Acıbadem Adana Hospital, Adana, Turkey.
Radiation Oncology Department, Acıbadem Ataşehir Hospital, İstanbul, Turkey.
Med Dosim. 2024;49(3):185-191. doi: 10.1016/j.meddos.2023.11.004. Epub 2023 Dec 14.
This study provides a concise and structured overview of a dosimetric comparison study conducted to assess the feasibility and effectiveness of 4 advanced radiotherapy techniques in treating brain metastases with hippocampus sparing and simultaneous integrated boost (HS-WBRT+SIB). Eleven patients with brain metastases previously treated with radiotherapy were included in the study. Planning CT scans with 2 mm slice thickness and MR imaging were used for contouring and dose prescription. The bilateral hippocampus and other organs at risk (OARs) were automatically contoured, and hippocampal avoidance regions (HAR) were defined as a 7 mm 3D expansion around the hippocampus. Gross tumor volume for each metastasis (GTV) and planning target volume for metastases (PTV) were delineated. The whole-brain CTV (CTV) and planning target volume for whole brain (PTV) were defined accordingly. Treatment planning and optimization were conducted using state-of-the-art radiotherapy techniques: Ethos, HyperArc, VMAT, and Tomotherapy. Tomotherapy achieved the highest D98% for PTV, indicating the best metastasis coverage. HyperArc plans showed the highest D98% for PTV, suggesting superior whole-brain coverage. Tomotherapy demonstrated significantly lower D98%, D2%, and D values for the hippocampus, indicating its superiority in sparing the hippocampus. VMAT resulted in the lowest D2% values for the eyes, optic nerves, brainstem, and hypophysis, showing the best sparing of these critical structures. Tomotherapy consistently achieved lower D values for parotids, oral cavity, and lips compared to the other techniques. The dosimetric comparison revealed distinct strengths and weaknesses for each radiotherapy technique. Tomotherapy excelled in sparing the hippocampus, while VMAT showed promise in sparing OARs. HyperArc plans demonstrated the best overall whole-brain coverage. These findings should guide clinicians in selecting the most suitable technique based on patient characteristics and institutional resources.
本研究提供了一项剂量学比较研究的简明结构概述，旨在评估 4 种先进的放射治疗技术在治疗伴有海马 spared 和同步整合 boost（HS-WBRT+SIB）的脑转移瘤中的可行性和有效性。该研究纳入了 11 例先前接受过放射治疗的脑转移瘤患者。采用 2mm 层厚的计划 CT 扫描和磁共振成像进行轮廓勾画和剂量规定。双侧海马和其他危及器官（OARs）被自动勾画，海马回避区（HAR）定义为围绕海马的 7mm 3D 扩展。每个转移灶的大体肿瘤体积（GTV）和转移灶的计划靶区（PTV）被描绘出来。相应地定义了全脑CTV（CTV）和全脑计划靶区（PTV）。使用最先进的放射治疗技术进行治疗计划和优化：Ethos、HyperArc、VMAT 和 Tomotherapy。Tomotherapy 实现了 PTV 的最高 D98%，表明对转移灶的覆盖最好。HyperArc 计划显示了 PTV 的最高 D98%，提示全脑覆盖较好。Tomotherapy 显示了海马体的 D98%、D2%和 D 值明显较低，表明其在保护海马体方面具有优势。VMAT 导致眼睛、视神经、脑干和垂体的 D2%值最低，表明对这些关键结构的保护最好。Tomotherapy 始终比其他技术对腮腺、口腔和嘴唇的 D 值较低。剂量学比较显示，每种放射治疗技术都有明显的优势和劣势。Tomotherapy 在保护海马体方面表现出色，而 VMAT 在保护 OARs 方面表现出潜力。HyperArc 计划显示了最佳的全脑覆盖。这些发现应指导临床医生根据患者特征和机构资源选择最合适的技术。
