The purpose of the study is to evaluate the safety and biodistribution of [I-124]-CPD-1028 Injection in cancer patients with solid tumours.

Up to 18 adult participants will be enrolled in this Phase 1a study to evaluate the safety and biodistribution of [I-124]-CPD-1028 Injection in patients with Insulin-like Growth Factor-1R (IGF-1R) upregulated solid tumours. All eligible subjects who have given written informed consent and qualify based on the study's inclusion/exclusion criteria will be enrolled in the study. Each enrolled subject will take part in six visits consisting of a screening visit, an Investigational Product administration visit, 3 assessment visits involving 2-3 Positron Emission Tomography/Computed Tomography (PET/CT) scans, and a follow-up safety telephone call. At Visit 2, subjects will start a course of treatment to protect the thyroid from radioactivity and may receive a pre-targeting dose of an additional investigational agent, CPD-1061.

Inclusion Criteria:

1. Age ≥18 years old with life expectancy > 12 weeks with confirmed metastatic or unresectable malignancy
2. Patients must have progressed after at least first-line chemotherapy and have an Eastern Cooperative Oncology Group (ECOG) status of 0, 1 or 2.
3. All patients must have archival tumour samples available and must have verification of IGF-1R expression.
4. Patients must have adequate organ and marrow function, vital signs and ECG.
5. Females of childbearing potential must not be pregnant and both males and females must use adequate forms of contraception.
6. Signed informed consent form
7. Subject must be compliant and have a high probability of completing the study.

Exclusion Criteria:

1. Patients who have had chemotherapy or radiotherapy within 2 weeks prior to entering the study or those who have not recovered from previous treatment.
2. Patients who have received a therapeutic radiopharmaceutical in the past year or who are currently receiving any other investigational agents.
3. Previous treatment with IGF-1R inhibitors.
4. Patients who are currently taking antithyroid medications and lithium or potassium sparing diuretics.
5. Subjects with known or suspected allergies or contraindications to the investigational agents and iodine
6. Subjects with uncontrolled intercurrent illness
7. Female subjects who are pregnant, planning to become pregnant or are lactating and/or breast-feeding.
8. Patients with diabetes requiring therapy unless controlled through diet or metformin.
9. Subjects who are undergoing monitoring of occupational ionising radiation exposure.
10. Subjects with hypothyroidism requiring thyroid supplementation