As a nuclear medicine physician and molecular imaging scientist, he has been performing clinical and basic reseach in nuclear oncology, radionuclide therapy, and nuclear cardiology. He and his colleagues perform clinical research on radionuclide therapy, radionuclide tumor imaging (PET, SPECT, and scintigraphy) and translational research on molecular imaging and molecular targeted therapy using tumor-specific radiotracers through in vivo imaging and clinical trials, especially on cancer. His recent researches extended from the above clinical and preclinical ones into the topics of PET/MR fusion molecular imaging studies on combinatory information of anatomical, physiological, and metabolic imaging modalities. He has published over 130 papers in peer-reviewed journals on nuclear medicine, molecular imaging, and radionuclide therapy. He has a continuing interest in radionuclide targeted therapy using multifunctional and target-specific radiotracers and tailored therapy using combined molecular imaging modalites.