MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms
MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms
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DOI：
10.1088/0031-9155/60/8/3097
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发表时间：
2015-04-21
影响因子：
3.5
通讯作者：
Greer, Peter B.
中科院分区：
文献类型：
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作者：
Sun, Jidi;Dowling, Jason;Greer, Peter B.
要在临床上实施 MRI 模拟或仅 MRI 治疗计划，需要进行全面的端到端测试以确保过程准确。本研究的目的是设计和构建一个模拟人类男性骨盆的几何体模，适用于 CT 和 MRI 扫描，并用它来测试 MRI 模拟的几何和剂量学方面，包括治疗计划和数字重建放射线照片 (DRR) 生成。在带有专用放射治疗床顶、激光桥和骨盆线圈支架的 3T MRI 模拟器中扫描带有模拟盆腔器官的液体填充骨盆形状体模。使用具有相同外部形状但具有内部畸变网格的第二个模型来量化 MR 图像的畸变。两个体模也经过 CT 扫描，作为几何和剂量测定的黄金标准。可变形图像配准用于量化 MR 畸变。使用在 CT 扫描上开发的七场 IMRT 计划进行剂量比较，将注量复制到 MR 图像并使用体电子密度重新计算。在没有校正的情况下，与 CT 扫描相比，MR 的最大骨盆畸变为 7.5 毫米，而供应商的 2D 和 3D 校正算法分别将其减少到 2.6 和 1.7 毫米。在感兴趣的内部器官的位置内，扭曲是
To clinically implement MRI simulation or MRI-alone treatment planning requires comprehensive end-to-end testing to ensure an accurate process. The purpose of this study was to design and build a geometric phantom simulating a human male pelvis that is suitable for both CT and MRI scanning and use it to test geometric and dosimetric aspects of MRI simulation including treatment planning and digitally reconstructed radiograph (DRR) generation.A liquid filled pelvic shaped phantom with simulated pelvic organs was scanned in a 3T MRI simulator with dedicated radiotherapy couch-top, laser bridge and pelvic coil mounts. A second phantom with the same external shape but with an internal distortion grid was used to quantify the distortion of the MR image. Both phantoms were also CT scanned as the gold-standard for both geometry and dosimetry. Deformable image registration was used to quantify the MR distortion. Dose comparison was made using a seven-field IMRT plan developed on the CT scan with the fluences copied to the MR image and recalculated using bulk electron densities.Without correction the maximum distortion of the MR compared with the CT scan was 7.5 mm across the pelvis, while this was reduced to 2.6 and 1.7 mm by the vendor's 2D and 3D correction algorithms, respectively. Within the locations of the internal organs of interest, the distortion was