Advanced Compton imagers: From universal exploration down to earth investigation and medical application

Since Compton imaging technology was first introduced about 40 years ago, it has been applied to many fields such as astrophysics, industrial and medical application. In the early days, Compton camera started to be used to search for signals from space in which the high energy radiation comes from point sources. The application in astrophysics was followed by the investigation for nuclear material in which advanced systems such as hybrid collimation method were applied. The Compton cameras were also utilized to monitor the environmental radiations caused by nuclear accidents. In medical application, both conventional and recoiled electron tracking method was applied for emission tomography. Recent researches presented Monte Carlo studies of multiple scattering Compton imaging methods for the detection of neutron induced gamma rays and scattered gamma rays in 3D radiation therapy. In summary, we present the historical trend of Compton camera and advanced Compton imagers made by us.