This brief review summarizes the major applications of artificial intelligence (AI), inparticular deep learning approaches, in molecular imaging and radiation therapyresearch. To this end, the applications of artificial intelligence in five generic fields ofmolecular imaging and radiation therapy, including PET instrumentation design, PETimage reconstruction quantification and segmentation, image denoising (low-doseimaging), radiation dosimetry and computer-aided diagnosis, and outcomeprediction are discussed. This review sets out to cover briefly the fundamentalconcepts of AI and deep learning followed by a presentation of seminalachievements and the challenges facing their adoption in clinical setting.