This is a feasibility single arm study designed for obtaining early data for optimization and evaluation of the clinical potential for a new MR technique using deuterated glucose. The purpose of the study is to investigate whether this technique is useful in metabolic imaging of glioblastoma multiforme (GBM) and whether radiochemotherapy (RCT) induced changes in the brain metabolism can be detected and might be predictive for treatment response. The study will include 10 patients with histologically verified GBM scheduled for standard RCT. Patients will have MRI scan performed before and within 8 weeks after starting RCT. The scans will include imaging after oral intake of deuterated glucose, so called deuterium metabolic imaging (DMI). Based on this study, the most optimal scanning technique, output variables of highest discriminative power with respect to RCT, and potential predictive markers for response will be selected for further clinical investigation.

Inclusion Criteria:

• Patients with newly diagnosed GBM IDHwt
• Scheduled for long-course radiotherapy
• At least 18 years of age
• WHO performance status 0-1
• Women who are not postmenopausal or surgically sterile must have a negative serum or urine pregnancy test performed at time of inclusion in the study. Safe and highly effective contraception must be used throughout the study meaning either hormonal anti-conception or an anti-fertility intrauterine device.
• Danish speaking
• Able and willing to comply after informed consent

Exclusion Criteria:

• Subjects who are receiving any other investigational agents.
• Previous or current treatment by radiation or chemotherapy.
• History of alcohol abuse or illicit drug use.
• Contraindications to MRI Pacemaker, neurostimulator or cochlea implant Metal foreign bodies such as fragments and irremovable piercings Unsafe medical implants Intracranial clips or coils Claustrophobia Largest circumference including arms > 160 cm
• Contraindications to gadolinium contrast eGFR ≤ 30 mL/min/1.73m2 Previous adverse reactions to gadolinium
• Not able or willing to receive radiotherapy
• Predicted remaining survival <3 months
• Insulin-treated diabetes

Patients with newly diagnosed GBM, idh-wt (performance 0-1) are enrolled before initiating radiochemotherapy. They are not allowed to have contraindications to MRI with contrast or diabetes.

Data will be shared in anonymized form if the local juridical office accepts that full anonymization can be achieved.