Hiroki Shirato is Professor of Radiation Medicine at Hokkaido University.

Dr. Shirato has investigated “tumor motion” during external radiotherapy. He invented real-time tumor-tracking radiotherapy (RTRT) system fusing radiation science and a real-time pattern-recognition technology and gold fiducial markers near the tumor. Dr. Shirato invented a new concept, “four-dimensional radiotherapy” which is now recognized as a major category of radiotherapy for improving accuracy related to tumor motion.

Dr. Shirato has received a large grant as one of the 30 top researchers in Japan for the project to improve proton beam and x-ray therapy. Major textbooks on radiation oncology and medical physics are introducing his RTRT system and findings about tumor motion. Several new radiotherapy devices have been invented based on articles and patents of his team. Now his interest is extending toward comprehensive medical science, tracking motion and function in life, from respiratory motion to molecular motion.