ABSTRACT
Just as heat and light transfer energy from the Sun to the Earth and the atmosphere, nuclear radiation transfers energy from a source to an absorbing medium. The source of nuclear radiation may be radioactive atoms or equipment such as X-ray machines. The effect of absorbing the more familiar types of radiation, such as heat, is to raise the temperature of the absorbing medium. If this medium is the human body, or part of it, the rise in temperature is sensed and, if it becomes excessive, avoiding action can be taken by sheltering under a sunshade (shielding), for example, or by moving further away from a fire (distance). However, a dose of gamma (g) radiation or other nuclear radiation that is large enough to be lethal to a human being would increase the body temperature by less than one-thousandth of 1°C. The body is therefore unable to sense even very high intensities of these types of radiation.
