This review discussed PET radiotracers developed as a LAT1-specific agent and how this new class of cancer-specific radiopharmaceuticals could deliver PET images with clinical properties we yearn for, such as high specificity toward various malignancies, robust non-cancer exclusion (mainly inflammatory reactions), accurate malignant lesion delineation, representative therapeutic monitoring, and long-term prognostication. The gene discussed is SLC7A5; the disease is cancer.