Centre Oscar Lambret, Department of Radiotherapy, Lille, France.
Centre Oscar Lambret, Department of Radiotherapy, Lille, France; AQUILAB SAS, Loos-lès-Lille, France; IEMN, UMR CNRS 8520, Villeneuve d'Ascq, France.
Phys Med. 2017 Oct;42:332-338. doi: 10.1016/j.ejmp.2017.04.028. Epub 2017 May 16.
Using magnetic resonance imaging (MRI) as the sole imaging modality for patient modeling in radiation therapy (RT) is a challenging task due to the need to derive electron density information from MRI and construct a so-called pseudo-computed tomography (pCT) image. We have previously published a new method to derive pCT images from head T1-weighted (T1-w) MR images using a single-atlas propagation scheme followed by a post hoc correction of the mapped CT numbers using local intensity information. The purpose of this study was to investigate the performance of our method with head zero echo time (ZTE) MR images. To evaluate results, the mean absolute error in bins of 20 HU was calculated with respect to the true planning CT scan of the patient. We demonstrated that applying our method using ZTE MR images instead of T1-w improved the correctness of the pCT in case of bone resection surgery prior to RT (that is, an example of large anatomical difference between the atlas and the patient).
使用磁共振成像（MRI）作为放射治疗（RT）中的唯一成像方式，由于需要从 MRI 中获取电子密度信息并构建所谓的伪计算机断层扫描（pCT）图像，这是一项具有挑战性的任务。我们之前已经发表了一种从头部 T1 加权（T1-w）MR 图像中使用单图谱传播方案来推导 pCT 图像的新方法，然后使用局部强度信息对映射的 CT 数进行事后校正。本研究的目的是研究我们的方法对头零回波时间（ZTE）MR 图像的性能。为了评估结果，根据患者的真实计划 CT 扫描，在 20HU 的分箱中计算了平均绝对误差。我们证明，与 T1-w 相比，使用 ZTE MR 图像应用我们的方法可改善 RT 前骨切除手术（即图谱与患者之间存在较大解剖差异的示例）中 pCT 的正确性。
