Assessing the Dosimetric Accuracy of Magnetic Resonance-Generated Synthetic CT Images for Focal Brain VMAT Radiation Therapy.
Assessing the Dosimetric Accuracy of Magnetic Resonance-Generated Synthetic CT Images for Focal Brain VMAT Radiation Therapy.
复制标题
DOI：
10.1016/j.ijrobp.2015.08.049
复制
发表时间：
2015-12-01
期刊：
影响因子：
--
通讯作者：
Balter JM
中科院分区：
文献类型：
--
作者：
Paradis E;Cao Y;Lawrence TS;Tsien C;Feng M;Vineberg K;Balter JM
评估由MRI数据生成的合成CT体积用于脑局灶放疗的剂量学准确性。对12例接受MR和CT成像作为外部射束治疗计划模拟的一部分的胶质瘤患者进行了一项研究。从MR图像生成合成CT（MRCT）体积。患者的临床治疗计划指令用于创建12个单独的体积调制弧治疗（VMAT）计划，然后在各自的CT和MRCT衍生电子密度图上优化10次。对源自优化标准的剂量度量以及监测单元和伽马分析进行了评价，以量化成像模式之间的差异。对于所有患者，MRCT和CT计划上的计划靶体积（PTV）剂量之间的平均差异分别为0.0%（范围-0.1至0.2%）（D95%）、0.0%（-0.7至0.6%）（D5%）和-0.2%（-1.0至0.2%）（Dmax）。MRCT计划显示，与CT计划相比，监测单位无显著变化（-0.4%）。在所有12名患者的85个结构中，危及器官（OAR）的平均Dmax差异为0.0戈伊（-2.2至1.9戈伊），当计算的剂量接近计划限制时，没有显著差异。在MRCT图像上优化的局灶性脑VMAT计划与标准CT优化计划显示出极好的剂量学一致性。PTV显示了等效的覆盖率，OAR未显示任何过量。这些结果表明，MRI衍生的合成CT体积可用于支持大多数颅内病变患者的治疗计划。
To assess the dosimetric accuracy of synthetic CT volumes generated from MRI data for focal brain radiotherapy. A study was conducted on 12 patients with gliomas who underwent both MR and CT imaging as part of their simulation for external beam treatment planning. Synthetic CT (MRCT) volumes were generated from the MR images. The patients’ clinical treatment planning directives were used to create 12 individual Volumetric Modulated Arc Therapy (VMAT) plans, which were then optimized 10 times on each of their respective CT and MRCT-derived electron density maps. Dose metrics derived from optimization criteria, as well as monitor units and gamma analyses, were evaluated to quantify differences between the imaging modalities. Mean differences between Planning Target Volume (PTV) doses on MRCT and CT plans across all patients were 0.0% (range −0.1 to 0.2%) for D95%, 0.0% (−0.7 to 0.6%) for D5%, and −0.2% (−1.0 to 0.2%) for Dmax. MRCT plans showed no significant change in monitor units (−0.4%) compared to CT plans. Organs at risk (OARs) had an average Dmax difference of 0.0 Gy (−2.2 to 1.9 Gy) over 85 structures across all 12 patients, with no significant differences when calculated doses approached planning constraints. Focal brain VMAT plans optimized on MRCT images show excellent dosimetric agreement with standard CT-optimized plans. PTVs show equivalent coverage, and OARs do not show any overdose. These results indicate that MRI-derived synthetic CT volumes can be used to support treatment planning of most patients treated for intracranial lesions.