Inclusion Criteria:

1. Signed informed consent.

2. Subjects aged ≥18 years.

3. Karnofsky status ≥60.

4. Negative urine pregnancy test in women of childbearing potential.

5. Histologically confirmed and /or highly suspicious GBM (Adult type Astrocytoma grade IV both IDH-Mutant and IDH-Wild Type) including primary, recurrent or stable enhancing residual or primary, recurrent or stable enhancing residual PDAC.

   a. GBM group i. Contrast enhanced Brain MRI image with results compatible with GBM within the 2 weeks of dosing day.

   ii. Tumor size of ≥ 1.0 cm in any dimension by MRI. iii. No antiangiogenic therapy within 4 weeks of the day of dosing. iv. No chemotherapy within 2 weeks of the day of dosing. v. Subjects receiving corticosteroids must be on a stable or decreasing dose regimen prior to enrollment b. PDAC group i. No chemotherapy within 2 weeks of the day of dosing ii. Tumor size of ≥ 1.0 cm in any dimension by MRI or CT

6. Recent blood test results (within 4 weeks pre-dose) as follows:

   1. WBC: ≥ 2 x 109/L
   2. Haemoglobin: ≥ 8 g/dL
   3. Platelets: ≥75 x 109/L
   4. ALT, AST, AP ≤ 5 times ULN
   5. Bilirubin: ≤ 2 times ULN
   6. Creatinine clearance ≥ 60 mL/min, calculated by the Cockcroft-Gault equation

Exclusion Criteria:

1. Known hypersensitivity to RMX-VH peptide analogue, 203Pb-RMX-VH-PIB, 203Pb (Lead) , or any of the excipients of 203Pb-RMX-VH-PIB.
2. Inability to undergo MRI or CT/SPECT/CT scans
3. Current somatic or psychiatric disease/condition that may interfere with consent or the objectives and assessments of the study.
4. Pregnancy or plans to conceive during the course of study participation.
5. In GBM groups participants requiring MRI: History of hypersensitivity or contraindication to gadolinium-based contrast agents, including prior allergic or anaphylactoid reactions to gadolinium contrast media, or any condition (e.g., severe renal impairment, acute kidney injury) that, in the investigator's judgment, increases the risk associated with gadolinium administration.
6. In PDAC groups participants requiring CT scans: Any contraindications to iodinated contrast agents include a history of severe hypersensitivity or allergic reaction to iodinated contrast media, significant renal impairment (e.g., eGFR < 30 mL/min/1.73 m² or acute kidney injury), uncontrolled hyperthyroidism or other thyroid disorders that may worsen with iodine exposure, prior contrast-induced nephropathy, pregnancy, and any unstable medical condition such as severe heart failure or hemodynamic instability that, in the investigator's judgment, increases the risk of contrast administration.
7. Male and female participants of childbearing potential who are unwilling or unable to use an acceptable method of contraception for the duration of the study.
8. Women who are breastfeeding
9. Participants who are currently receiving treatment with statins (HMG-CoA reductase inhibitors), including but not limited to atorvastatin, rosuvastatin, pitavastatin, simvastatin, lovastatin, pravastatin, or fluvastatin, are excluded unless the medication has been discontinued for at least four (4) drug half-lives prior to administration of the investigational product