The aim of this study is to establish FET-PET as an additional therapy assessment parameter in patients diagnosed with a glioblastoma multiforme receiving radiochemotherapy and adjuvant chemotherapy after previous resection or biopsy.

Inclusion Criteria:

• neuroradiologically suspected Glioblastoma multiforme
• histological verification will be obtained either by microsurgery or by stereotactic biopsy. The neuropathological diagnosis will be verified by a reference neuropathologist
• patients will undergo radiochemotherapy subsequent to surgical procedure
• patients older than 18 years
• Karnofsky Performance Score >=70
• pregnant or nursing female patients will not be included in this study
• safe contraceptive methods during the radiochemotherapy and chemotherapy

Exclusion Criteria:

• patients in whom informed consent cannot be obtained due to organic brain syndrome or insufficient language skills
• patients who cannot lie quiet for a time period of app. two hours during the FET-PEt scan
• medical history of a metastatic brain disease
• patients in whom an MRI scan cannot be performed due to claustrophobia metallic protheses or pacemakers etc.

Patients who have been referred to a neurosurgical department for diagnosis and therapy of a brain tumor