PROJECT SUMMARY / ABSTRACT The Postgraduate Training Program in Medical Imaging (PTPMI) provides recent doctoral graduates with research training in medical imaging technology as it pertains to normal and pathophysiological functions applied to nuclear medicine (PET and SPECT), magnetic resonance imaging (MRI), Optical Imaging, Image Processing and Artificial Intelligence (AI). The importance of the field of Medical Imaging Sciences has been recognized by the establishment of the National Institute of Biomedical Imaging and Bioengineering (NIBIB). And within medical imaging science, imaging research and technology and more recently AI have revolutionized the practice of Radiology. Trainees may enter the field of medical imaging research after study of a curriculum that focuses directly on radiological science or after earning a doctoral degree in the physical sciences, mathematics, biophysics, or computer science. MDs with established professional interest in quantitative imaging research are also encouraged to apply. The PTPMI provides trainees an innovative training and strong background via customized and diverse mentoring as well as structured didactic courses and seminars, enabling graduates to critically evaluate the field and develop their own research ideas. Trainees participate in leading--‐edge research, with the opportunity to interact with a world--‐class multi-institutional faculty in a setting that combines the resources of the Harvard Medical School (HMS), and the Harvard--‐affiliated Teaching Hospitals. The rationale for this program is based on several factors: 1) the growing need for basic scientists with training in medical imaging sciences applied in modalities such as PET, SPECT, MR, CT and optical; 2) the availability of outstanding research programs that provide exciting opportunities for trainees in imaging technologies and AI; 3) the availability of cutting-edge facilities with commercial and prototype imaging systems; 4) an unusually strong and diverse group of mentors and, in addition, a faculty who provide additional expertise and extend the range of contacts available to trainees; and 5) long--‐standing, diverse collaborations, both within the Massachusetts General Hospital (MGH) as well as HMS, other HMS--‐affiliated hospitals, Harvard University, and the Massachusetts Institute of Technology (MIT). PTPMI has been characterized over the past funding period by exceptionally strong outcomes in terms of inclusion and diversity with 32% of T32 trainees URM and 36% women, as well as in terms of career outcomes with 60% T32 alumni in academic positions and 40% in industrial R&D positions, all in areas directly related to NIBIB priorities in biomedical imaging and bioengineering technologies.