Radiation hormesis is a concept that pervades radiobiological exposures;low doses enhance immune response, while higher doses inhibit immune response. Low-dose Total-Body Irradiation (TBI) therapy offers radiation treatment to cancer patients using the concepts of radiation hormesis and show very good success rates. This phenomenon has been reported elsewhere as the “abscopal effect” and considering the marginal success rates of other treatment agents, like the immunotherapy drug Ipilimumab, TBI therapy may prove to be the missing link to a better cancer treatment.