McGuire Sarah M, Menda Yusuf, Ponto Laura L Boles, Gross Brandie, TenNapel Mindi, Smith Brian J, Bayouth John E
University of Iowa.
J Appl Clin Med Phys. 2014 Jul 8;15(4):129–136. doi: 10.1120/jacmp.v15i4.4780.
The purpose of this study was to determine the ability of regions identified with bony landmarks on CT imaging to accurately represent active bone marrow when compared to FLT PET imaging. These surrogate regions could then be used to create a bone marrow sparing radiation therapy plan when FLT PET imaging is not available. Whole body (WB) FLT PET images were obtained of 18 subjects prior to chemoradiation therapy. The FLT image of each subject was registered to a CT image acquired for that subject to obtain anatomic information of the pelvis. Seventeen regions were identified based on features of the pelvic bones, sacrum, and femoral heads. The probability of FLT uptake being located in each of 17 different CT-based regions of the bony pelvis was calculated using Tukey's multiple comparison test. Statistical analysis of FLT uptake in the pelvis indicated four distinct groups within the 17 regions that had similar levels of activity. Regions located in the central part of the pelvis, including the superior part of the sacrum, the inner halves of the iliac crests, and the L5 vertebral body, had greater FLT uptake than those in the peripheral regions (p-value < 0.05). We have developed a method to use CT-defined pelvic bone regions to represent FLT PET-identified functional bone marrow. Individual regions that have a statistically significant probability of containing functional bone marrow can be used as avoidance regions to reduce radiation dose to functional bone marrow in radiation therapy planning. However, because likely active bone marrow regions and pelvic targets typically overlap, patient-specific spatial detail may be advantageous in IMRT planning scenarios and may best be provided using FLT PET imaging.
本研究的目的是确定在CT成像上用骨性标志识别的区域与FLT PET成像相比，准确代表活跃骨髓的能力。当无法获得FLT PET成像时，这些替代区域可用于制定骨髓保护放疗计划。在放化疗前，对18名受试者进行了全身（WB）FLT PET成像。将每个受试者的FLT图像与该受试者获取的CT图像配准，以获得骨盆的解剖信息。根据骨盆骨、骶骨和股骨头的特征确定了17个区域。使用Tukey多重比较检验计算FLT摄取位于骨盆17个不同CT区域中每个区域的概率。对骨盆中FLT摄取的统计分析表明，17个区域内有四个不同的组，其活性水平相似。位于骨盆中部的区域，包括骶骨上部、髂嵴内半部和L5椎体，其FLT摄取高于周边区域（p值<0.05）。我们已经开发出一种方法，使用CT定义的骨盆骨区域来代表FLT PET识别的功能性骨髓。在放疗计划中，具有统计学显著概率包含功能性骨髓的各个区域可作为避让区域，以减少对功能性骨髓的辐射剂量。然而，由于可能的活跃骨髓区域和盆腔靶区通常重叠，在IMRT计划方案中，患者特异性的空间细节可能具有优势，并且最好使用FLT PET成像来提供。
