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Patients are usually treated in the supine position (lying on their backs).Radioactive elements such as uranium (U) and thorium (Th) decay naturally to form different elements or isotopes of the same element.Literacy: Universe, galaxy, Milky way, starts, sun, solar system, planets, comets, asteroids, meteorites, time, big bang, Earth, crust mantle and core Numeracy: The diameter of the Sun is 109 times larger than the diameter of the Earth and consumes about 300,000 tons of hydrogen every second.It is approximately 4.5 billion years old about half way through its life.(Isotopes are atoms of any elements that differ in mass from that element, but possess the same general chemical and optical properties.) This decay is accompanied by the emission of radiation or particles (alpha, beta, or gamma rays) from the nucleus, by nuclear capture, or by ejection of orbital electrons.A number of isotopes decay to a stable product, a so-called daughter isotope, in a single step (for example, carbon-14), whereas others involve many steps before a stable isotope is formed.By throwing out electrons you produce charged particles called ions. We are surrounded by background radiation all of the time!This means it is the radiation responsible for ionising molecules. Small doses of radiation over a long period of time can cause the cells to multiply. Background radiation comes from the soil, rocks, the air, water, plants, building materials and food.
Radiotherapy is widely used for the treatment of some kinds of cancer.Therefore the irradiated substance is sterile but NOT radioactive.