Radiation is only the invisible threat to the population since earth had been radioactive and it was formed about 4500 million years ago. In fact the age of the earth can be calculated from a detailed examination of its radioactivity; particularly the decay of uranium to lead. Natural radioactivity contributes about 90 percent of the total radiation which originates from extraterrestrial sources as well as from radioactive elements in the earth's crust. In most places on earth the natural radioactivity varies only within relatively narrow limits, but in some localities there are wide deviations from normal levels owing to the presence of abnormally high concentrations of radioactive minerals in the local soils. So the only invisible threat is the Radiation which is continuously exposed to population and to the environmental living bodies from all around us. So the detail procedure and analysis for measuring such invisible threat of radiation has been done well.