摘要：In 1958 the speaker believed that background radiation might cause a fatal cancer. In 1970 he believed there was no risk from background or from the small doses received from diagnostic uses of X-rays. Since 1990 he has come to believe that for good health most people need more radiation than they receive from nature. The talk will emphasize the results of two large British radiologists who entered the field between 1955 and 1979, when compared to all other male English physicians of the same age. Had a 29% lower cancer death rate, a 36% lower death rate from non-cancer and a 32% lower death rate from all causes. The chances of such a health improvement being accidental is less than one in one thousand. The lower death rate from all causes results in more than a three year increase in longevity-the same increase in longevity that would result ff all cancer were curable. The US Government sponsored nuclear shipyard worker study shows that the 28,000 nuclear shipyard workers with the greatest radiation doses, when compared to 32,500 shipyard workers who had no on-the-job radiation, had significantly less cancer and a 24% lower death rate from all causes. That is, the nuclear workers had nearly a three-year increase in longevity.The chance of that health improvement being accidental is less than one in ten million billion. The talk will describe a double blind study to test the hypothesis that a moderate dose of ionizing radiation stimulates the immune system of senior citizens in the I.S. Gulf States where cancer mortality is 25% greater than in the mountains, which have about 300% more background radiation than the Gulf States. Radiation deficiency may be a health problem in many areas of the world.