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.