Gross M W, Weber W A, Feldmann H J, Bartenstein P, Schwaiger M, Molls M
Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie, Technische Universität München, Germany.
Int J Radiat Oncol Biol Phys. 1998 Jul 15;41(5):989-95. doi: 10.1016/s0360-3016(98)00183-7.
The aim of the study was to determine the impact of positron emission tomography using the glucose analogue fluorine-18-fluorodeoxyglucose (FDG-PET) on the delineation of the target volume in three-dimensional radiation treatment planning of primary brain tumors.
In 18 patients with histologically proven (8x biopsy, 10x subtotal resection) primary brain tumors (8 astrocytomas grade III, one mixed glioma grade III, and 9 glioblastomas), magnetic resonance imaging (MRI) with gadolinium-DTPA and FDG-PET were performed in radiation treatment position within the same week. A computer program was developed for fusion of the PET and MR images. On corresponding axial slices, FDG uptake was compared to contrast enhancement in T1-weighted and to signal hyperintensity in T2-weighted MR images. Based on PET and MRI data, three-dimensional treatment planning was performed. All patients underwent linear accelerator (LINAC) radiotherapy.
In MRI, all tumors and the surrounding edema were visible as hyperintense lesions in the T2-weighted images. 17/18 tumors showed contrast enhancement. In FDG-PET, 16 tumors showed hypermetabolism compared to normal white matter, whereas only 8/18 tumors showed hypermetabolism compared to normal gray matter. White matter edema was associated with decreased FDG uptake in all patients. The area of increased FDG uptake correlated closely with contrast enhancement, only in one case the volume of increased FDG uptake was larger than the area of contrast enhancement. Mean tumor volumes obtained by MRI T1 + Gd, T2, and PET were 30, 106, and 10 ml, respectively. Survival was comparable to data in the literature with a 1-year survival of 39% and a median survival of 310 days.
Only in a minority of patients did FDG-PET provide additional information for radiation treatment planning. This is mainly caused by the high intensity of FDG uptake in normal brain tissue. PET may be of greater value in the definition of regions that should obtain a radiation dose boost.
本研究的目的是确定使用葡萄糖类似物氟 - 18 - 氟脱氧葡萄糖的正电子发射断层扫描（FDG - PET）对原发性脑肿瘤三维放射治疗计划中靶区勾画的影响。
18例经组织学证实（8例活检，10例次全切除）的原发性脑肿瘤患者（8例III级星形细胞瘤，1例III级混合性胶质瘤，9例胶质母细胞瘤），在同一周内于放射治疗体位进行钆 - DTPA磁共振成像（MRI）和FDG - PET检查。开发了一个用于融合PET和MR图像的计算机程序。在相应的轴位切片上，将FDG摄取与T1加权像中的对比增强以及T2加权MR图像中的信号高强化进行比较。基于PET和MRI数据进行三维治疗计划。所有患者均接受直线加速器（LINAC）放射治疗。
在MRI中，所有肿瘤及其周围水肿在T2加权像中均表现为高强化病变。17/18例肿瘤显示对比增强。在FDG - PET中，与正常白质相比，16例肿瘤显示代谢增高，而与正常灰质相比，仅8/18例肿瘤显示代谢增高。所有患者的白质水肿均与FDG摄取减少相关。FDG摄取增加的区域与对比增强密切相关，仅1例FDG摄取增加的体积大于对比增强的面积。通过MRI T1 + Gd、T2和PET获得的平均肿瘤体积分别为30、106和10 ml。生存率与文献数据相当，1年生存率为39%，中位生存期为310天。
仅少数患者中，FDG - PET为放射治疗计划提供了额外信息。这主要是由于正常脑组织中FDG摄取强度较高所致。PET在确定应给予放射剂量增加的区域方面可能具有更大价值。
