PET scans detect diseases at the metabolic and molecular level, enabling earlier diagnosis compared to traditional CT and MRI scans that identify structural changes later. The technology plays a critical role in cancer staging and restaging, evaluating treatment response, detecting recurrence, and assessing prognosis. It is particularly useful for various malignancies including brain tumours, head and neck cancers, lung carcinoma, breast carcinoma, colorectal carcinoma, and others. Beyond oncology, PET scans are also applied in cardiology, neurology, and for evaluating infections and inflammatory conditions where conventional imaging falls short.