Rehani has made contributions in patient dosimetry in over 70 countries by his actions through the International Atomic Energy Agency (IAEA). He established a website on radiation protection of patients; the smart card project for tracking radiation exposures of patients; research on radiation-induced cataract in the eyes of interventional cardiologists and support staff; research on radiation safety of children in developing countries; development of training material on radiation protection; and training of doctors using fluoroscopy outside radiology (cardiologists, urologists, orthopedic surgeons, vascular surgeons, gastroenterologist, and gynecologists) from over 60 countries. He also set up the EuroSafe Imaging program by the European Society of Radiology. He has recently developed a new concept on “acceptable quality dose (AQD)” to take into account limitations of diagnostic reference levels (DRLs), which have been used as an index in radiation protection for nearly three decades. He is currently Chair of the Program Committee of the IAEA International Conference on Radiation Protection in Medicine.