Tanaka Hidekazu, Yamaguchi Takahiro, Hachiya Kae, Miwa Kazuhiro, Shinoda Jun, Hayashi Masahide, Ogawa Shinichi, Nishibori Hironori, Goshima Satoshi, Matsuo Masayuki
Department of Radiology, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan.
Department of Neurosurgery, Chubu Medical Centre for Prolonged Traumatic Brain Dysfunction, Shimokobi 630, Kobicho, Minokamo 505-8503, Japan.
Rep Pract Oncol Radiother. 2018 May-Jun;23(3):215-219. doi: 10.1016/j.rpor.2018.04.003. Epub 2018 Apr 25.
To define the optimal margin on MRI scans in the re-radiation planning of recurrent glioblastoma using methionine positron emission tomography (MET-PET).
It would be very useful if the optimal margin on MRI to cover the uptake area on MET-PET is known.
CT, MRI, and MET-PET were performed separately over the course of 2 weeks. Among the MRI scans, we used the contrast-enhanced T1-weighted images (Gd-MRI) and T2-weighted images (T2-MRI). The Gd-MRI-based clinical target volume (CTV) (CTV-Gd) and the T2-MRI-based CTV (CTV-T2) were defined as the contrast-enhanced area on Gd-MRI and the high intensity area on T2-MRI, respectively. We defined CTV x mm (x = 5, 10, 15, 20) as x mm outside the CTV. MET-PET-based CTV (CTV-MPET) was defined as the area of accumulation of MET-PET. We calculated the sensitivity and specificity of CTV-Gd and CTV-T2 following comparison with CTV-MPET, which served as the gold standard in this study.
The sensitivity of CTV-T2 5 mm (98%) was significantly higher than CTV-T2 (87%), and there was no significant difference in the sensitivity between CTV-T2 5 mm and CTV T2 10, 15, or 20 mm. The sensitivity of CTV-Gd 20 mm (97%) was lower than that of CTV-T2 5 mm (98%).
A margin of at least 5 mm around the high intensity area on T2-MRI is necessary in the target volume delineation of recurrent glioblastoma for the coverage of MET-PET findings in re-radiation therapy planning.
利用蛋氨酸正电子发射断层扫描（MET-PET）确定复发性胶质母细胞瘤再程放疗计划中MRI扫描的最佳边界。
若已知MRI上覆盖MET-PET摄取区域的最佳边界，将非常有用。
在2周内分别进行CT、MRI和MET-PET检查。在MRI扫描中，我们使用了对比增强T1加权图像（Gd-MRI）和T2加权图像（T2-MRI）。基于Gd-MRI的临床靶体积（CTV）（CTV-Gd）和基于T2-MRI的CTV（CTV-T2）分别定义为Gd-MRI上的对比增强区域和T2-MRI上的高强度区域。我们将CTV x mm（x = 5、10、15、20）定义为CTV外x mm处。基于MET-PET的CTV（CTV-MPET）定义为MET-PET的积聚区域。与作为本研究金标准的CTV-MPET比较后，我们计算了CTV-Gd和CTV-T2的敏感性和特异性。
CTV-T2 5 mm的敏感性（98%）显著高于CTV-T2（87%），CTV-T2 5 mm与CTV-T2 10、15或20 mm之间的敏感性无显著差异。CTV-Gd 20 mm的敏感性（97%）低于CTV-T2 5 mm的敏感性（98%）。
在复发性胶质母细胞瘤的靶区勾画中，为在再程放疗计划中覆盖MET-PET结果，T2-MRI上高强度区域周围至少5 mm的边界是必要的。
