• Understand and voluntarily sign the informed consent form prior to any study related procedure and/or assessments being conducted.

• Are Male or Female, and aged 18 years or older, at the time of signing the informed consent.

• Have histologically confirmed intracranial glioblastoma (per WHO 2021 definition) following surgical resection. Tumours primarily localised in the infratentorial compartment will be excluded.

• Have had prior surgery for glioblastoma, but no systemic therapy or radiation therapy for GBM.

• Have a Karnofsky Performance Status ≥70.

• Plan to begin chemoradiation therapy 3-6 weeks after surgical resection with Stupp regimen.

• Have adequate organ function at Screening:

‣ 1 Bone marrow: 7.1.1 Leukocytes ≥3,000/mL 7.1.2 Absolute neutrophil count ≥1500/mL 7.1.3 Platelets ≥100,000/mL 7.1.4 Haemoglobin ≥9g/dL 7.2 Liver function: 7.2.1 Total bilirubin ≤1.5×the upper limit of normal (ULN). For patients with known Gilbert's Syndrome ≤3×ULN is permitted 7.2.2 Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≤2.5×ULN 7.3 Renal function: 7.3.1 Serum/plasma creatinine ≤1.5×ULN or creatinine clearance ≥50 mL/min

• Have at least 6 slides without staining or a tissue block (frozen or paraffin-embedded) available from a previous biopsy or surgery (tumour sample previously archived).

• Have the capacity to understand the study and be able and willing to comply with all protocol requirements, including compliance with the radiation protection guidelines (including hospital admissions and isolation) that are applied by the treating institution to protect their contacts and the public.

⁃ Agree to practice adequate precautions to prevent pregnancy to avoid potential problems associated with radiation exposure to the unborn child.

⁃ Females must have a negative pregnancy test at screening and on dosing day, must not be lactating.