Uptake of O-(2-[¹⁸F]fluoroethyl)-L-tyrosine in reactive astrocytosis in the vicinity of cerebral gliomas

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• 作者：Marc D. Piroth ; Jeyakamalini Prasath ; Antje Willuweit ; Gabriele Stoffels ; Bernd Sellhaus ; Ansel van Osterhout ; Stefanie Geisler ; Nadim J. Shah ; Michael J. Eble ; Heinz H. Coenen ; Karl-Josef Langen
• 关键词：Cerebral glioma ; PET ; Astrogliosis ; O-(2-[18F]fluoroethyl)-L-tyrosine ; Autoradiography
• 刊名：Nuclear Medicine and Biology
• 出版年：2013
• 出版时间：August, 2013
• 年：2013
• 卷：40
• 期：6
• 页码：795-800
• 全文大小：1252 K

文摘

PET using O-(2-[¹⁸F]fluoroethyl)-L-tyrosine (¹⁸F-FET) allows improved imaging of tumor extent of cerebral gliomas in comparison to MRI. In experimental brain infarction and hematoma, an unspecific accumulation of ¹⁸F-FET has been detected in the area of reactive astrogliosis which is a common cellular reaction in the vicinity of cerebral gliomas. The aim of this study was to investigate possible ¹⁸F-FET uptake in the area of reactive gliosis in the vicinity of untreated and irradiated rat gliomas.

Methods

F98-glioma cells were implanted into the caudate nucleus of 33 Fisher CDF rats. Sixteen animals remained untreated and in 17 animals the tumor was irradiated by Gamma Knife 5-8 days after implantation (2/50 Gy, 3/75 Gy, 6/100 Gy, 6/150 Gy). After 8-17 days of tumor growth the animals were sacrificed following injection of ¹⁸F-FET. Brains were removed, cut in coronal sections and autoradiograms of ¹⁸F-FET distribution were produced and compared with histology (toluidine blue) and reactive astrogliosis (GFAP staining). ¹⁸F-FET uptake in the tumors and in areas of reactive astrocytosis was evaluated by lesion to brain ratios (L/B).

Results

Large F98-gliomas were present in all animals showing increased ¹⁸F-FET-uptake which was similar in irradiated and non-irradiated tumors (L/B: 3.9 ¡À 0.8 vs. 4.0 ¡À 1.3). A pronounced reactive astrogliosis was noted in the vicinity of all tumors that showed significantly lower ¹⁸F-FET-uptake than the tumors (L/B: 1.5 ¡À 0.4 vs. 3.9 ¡À 1.1). The area of ¹⁸F-FET-uptake in the tumor was congruent with histological tumor extent in 31/33 animals. In 2 rats irradiated with 150 Gy, however, high ¹⁸F-FET uptake was noted in the area of astrogliosis which led to an overestimation of the tumor size.

Conclusions

Reactive astrogliosis in the vicinity of gliomas generally leads to only a slight ¹⁸F-FET-enrichment that appears not to affect the correct definition of tumor extent for treatment planning.