Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions.
Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions.
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DOI：
10.1186/1748-717x-5-62
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发表时间：
2010-06-30
期刊：
影响因子：
--
通讯作者：
Nyholm T
中科院分区：
文献类型：
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作者：
Jonsson JH;Karlsson MG;Karlsson M;Nyholm T
由于上级软组织对比度，磁共振成像（MRI）作为计算机断层扫描（CT）的补充，在放射治疗的目标定义过程中的使用正在增加。为了保持工作流程简单和成本效益，并减少患者剂量，很自然地争取完全基于MRI的治疗计划程序。在本研究中，我们研究了使用MRI数据的体积密度分配时不同治疗区域的剂量计算准确性，并将其与使用CT数据的治疗计划进行比较。回顾性收集了40例前列腺癌、肺癌、头颈癌或脑癌患者的MR和CT资料。对有和无不均匀性校正的CT数据和有体积密度分配的MRI或CT数据的计算进行了比较。使用组织、骨、肺和气腔的手动分割来分配堆密度。对CT数据进行不均匀性校正和对体积密度分配的MR数据进行计算之间的偏差很小。达到规定剂量所需的监测单位数量的最大差异为1.6%。该结果还包括可能的几何变形的影响。当使用MRI数据时，在进行适当的堆密度分配时，研究治疗部位的剂量计算准确度不会显著受损。关于治疗计划，MRI可以在治疗工作流程的所有步骤中取代CT，减少对患者的辐射暴露，消除结合MR和CT时可能发生的任何系统配准误差，并减少额外CT检查的时间和成本。
Because of superior soft tissue contrast, the use of magnetic resonance imaging (MRI) as a complement to computed tomography (CT) in the target definition procedure for radiotherapy is increasing. To keep the workflow simple and cost effective and to reduce patient dose, it is natural to strive for a treatment planning procedure based entirely on MRI. In the present study, we investigate the dose calculation accuracy for different treatment regions when using bulk density assignments on MRI data and compare it to treatment planning that uses CT data. MR and CT data were collected retrospectively for 40 patients with prostate, lung, head and neck, or brain cancers. Comparisons were made between calculations on CT data with and without inhomogeneity corrections and on MRI or CT data with bulk density assignments. The bulk densities were assigned using manual segmentation of tissue, bone, lung, and air cavities. The deviations between calculations on CT data with inhomogeneity correction and on bulk density assigned MR data were small. The maximum difference in the number of monitor units required to reach the prescribed dose was 1.6%. This result also includes effects of possible geometrical distortions. The dose calculation accuracy at the investigated treatment sites is not significantly compromised when using MRI data when adequate bulk density assignments are made. With respect to treatment planning, MRI can replace CT in all steps of the treatment workflow, reducing the radiation exposure to the patient, removing any systematic registration errors that may occur when combining MR and CT, and decreasing time and cost for the extra CT investigation.