Hippocampal avoidance with volumetric modulated arc therapy in melanoma brain metastases - the first Australian experience
Hippocampal avoidance with volumetric modulated arc therapy in melanoma brain metastases - the first Australian experience
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DOI：
10.1186/1748-717x-8-62
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发表时间：
2013-03-18
影响因子：
3.6
通讯作者：
Haydu, Lauren
中科院分区：
文献类型：
--
作者：
Awad, Raef;Fogarty, Gerald;Haydu, Lauren
目的：体积调制电弧治疗（VMAT）可以在短时间内提供与调强放疗（IMRT）相似的剂量分布；这允许将IMRT治疗扩展到缓解性情况，如脑转移（BMs）。VMAT可以在海马回避的同时提供全脑放疗（WBRT）和同步综合增强（SIB），以实现脑转移的立体定向放疗（SRT）。本研究是对我们在我院使用VMAT治疗脑转移瘤的经验进行审核。方法和材料：在融合诊断性钆增强T1加权MRI/计划CT图像上对转移灶进行体积轮廓。危险器官包括海马、视神经、视交叉、眼和脑干。海马体在神经放射学家的帮助下被手工勾画成一个成对的器官。WBRT和SIB被整合到一个单一的计划中。结果：2010年3月至2012年2月，30例73例脑转移患者接受VMAT治疗。平均随访时间3.5个月。在26例患者中，脑转移来自原发性黑色素瘤，其余4例患者来自非小细胞肺癌（n=2）、原发性乳腺癌和肉瘤。平均年龄为60岁。男女比例为2:1。5例患者治疗时没有海马回避（HA）意图。WBRT的中位剂量为31 Gy，脑转移的中位SIB剂量为50 Gy，中位剂量为15个分数。BMs的平均值为：GTV = 6.9 cc, PTV = 13.3 cc，一致性指数= 8.6，均匀性指数= 1.06。以HA意向治疗的患者海马平均剂量和最大剂量分别为20.4 Gy和32.4 Gy。VMAT治疗的平均时间为3.43分钟，而WBRT治疗的平均时间为1.3分钟。在分析时，25个可评估病变中有20个得到控制。治疗耐受性良好；1例患者报告4级毒性。结论：VMAT治疗脑转移瘤是可行的、安全的，其生存时间和毒性与常规SRT+/-WBRT相似。VMAT的优点是可以在一台机器上同时交付WBRT和SRT。
Purpose: Volumetric modulated arc therapy (VMAT) can deliver intensity modulated radiotherapy (IMRT) like dose distributions in a short time; this allows the expansion of IMRT treatments to palliative situations like brain metastases (BMs). VMAT can deliver whole brain radiotherapy (WBRT) with hippocampal avoidance and a simultaneous integrated boost (SIB) to achieve stereotactic radiotherapy (SRT) for BMs. This study is an audit of our experience in the treatment of brain metastases with VMAT in our institution.Methods and materials: Metastases were volumetrically contoured on fused diagnostic gadolinium enhanced T1 weighted MRI/planning CT images. Risk organs included hippocampus, optic nerve, optic chiasm, eye, and brain stem. The hippocampi were contoured manually as one paired organ with assistance from a neuroradiologist. WBRT and SIB were integrated into a single plan.Results: Thirty patients with 73 BMs were treated between March 2010 and February 2012 with VMAT. Mean follow up time was 3.5 months. For 26 patients, BMs arose from primary melanoma and for the remaining four patients from non-small cell lung cancer (n=2), primary breast cancer, and sarcoma. Mean age was 60 years. The male to female ratio was 2: 1. Five patients were treated without hippocampal avoidance (HA) intent. The median WBRT dose was 31 Gy with a median SIB dose for BMs of 50 Gy, given over a median of 15 fractions. Mean values for BMs were as follows: GTV = 6.9 cc, PTV = 13.3 cc, conformity index = 8.6, homogeneity index = 1.06. Mean and maximum hippocampus dose was 20.4 Gy, and 32.4 Gy, respectively, in patients treated with HA intent. Mean VMAT treatment time from beam on to beam off for one fraction was 3.43 minutes, which compared to WBRT time of 1.3 minutes. Twenty out of 25 assessable lesions at the time of analysis were controlled. Treatment was well tolerated; grade 4 toxicity was reported in one patient. The median overall survival was 9.40 monthsConclusions: VMAT for BMs is feasible, safe and associated with a similar survival times and toxicities to conventional SRT+/-WBRT. The advantage of VMAT is that WBRT and SRT can be delivered at the same time on one machine.