Medical imaging studies can be divided into structural vs. functional modalities, with PET imaging being a common functional modality used in daily practice. PET imaging involves introducing positron-emitting radiotracers into the body and acquiring three-dimensional image maps of their distribution, which can help diagnose various conditions by highlighting abnormal metabolic processes. FDG-PET/CT imaging is particularly useful in oncology for detecting abnormal glucose uptake associated with cancer, although its effectiveness can vary across different cancer types and it may produce false positives or negatives due to various physiological and pathological factors.