The Effect of Glioblastoma PSMA Expression Following Tumour VEGF Blockade From Bevacizumab

Inclusion Criteria: * \> 18 year of age * ECOG 0-2 * Able to provide informed consent for the study * Minimum of 1 month from completion of radiotherapy with clinical or radiography evidence suggesting residual tumour * Confirmed glioblastoma IDH1/2 wildtype (WHO2021) * For bevacizumab treatment as per treating physician * Able to comply with trial requirements Exclusion Criteria: * No major organ impairment that would likely lead to unacceptable toxicities- eg significant cardiac, hepatic, renal or haematologic dysfunction (based on clinician assessment) * Any contraindication to bevacizumab, MRI gadolinium contrast or 68Ga-PSMA-617 radioisotope * Any implant, foreign body, 3T MRI incompatible device or other contraindication to MRI imaging * Does not fulfill PBS requirements for bevacizumab * Women lactating, pregnant or of child baring potential who are not willing to avoid pregnancy during the study