CT imaging is particularly useful because it can show several types of tissue - lung, bone, soft tissue and blood vessels - with greater clarity than X-ray images. Though a CT scan uses radiation, it is not a nuclear imaging technique, because the source of radiation - the X-rays - comes from equipment outside the body as opposed to a radiopharmaceutical inside the body.
PET scans are frequently combined with CT scans, with the PET scan providing functional information where the radioisotope has accumulated and the CT scan refining the location. The primary advantage of PET imaging is that it can provide the examining physician with quantified data about the radiopharmaceutical distribution in the absorbing tissue or organ. Radioisotopes Different isotopes of the same element have the same number of protons in their atomic nuclei but differing numbers of neutrons.
How do radioisotopes occur? Radioactive decay Atoms with an unstable nucleus regain stability by shedding excess particles and energy in the form of radiation. How are radioisotopes used? Radioisotope Half-life Use Hydrogen-3 tritium Carbon 5, years Used to measure the age of organic material up to 50, years old.
Chlorine , years Used to measure sources of chloride and the age of water up to 2 million years old. Lead Chromium Manganese Produced in reactors. Cobalt 5. Also used to irradiate fruit fly larvae in order to contain and eradicate outbreaks, as an alternative to the use of toxic pesticides. Zinc Produced in cyclotrons. Technetiumm 6.
Produced in 'generators' from the decay of molybdenum, which is in turn produced in reactors. Caesium Ytterbium Iridium Also used to trace sand to study coastal erosion. Gold 2. Also used to trace factory waste causing ocean pollution, and to study sewage and liquid waste movements. Americium Radioisotope Half-life Use Phosphorus The difference in terminology is usually that gamma rays come from nuclear decay, while X-rays come from electron orbitals. These wavelengths of electromagnetic radiation contain enough energy to push an electron out of its orbit around the atom — yet again forming an ion.
They are stopped by very dense materials such as lead or large amounts of earth or concrete. Alpha particles, with two neutrons and two protons, are essentially helium ions. These can strip the electrons from another atom in order to become helium atoms. Beta particles are simply free electrons that can be captured by atoms just like any other electron. Luckily, protection from these is reasonably easy. Alpha particles are blocked by a piece of paper, and beta particles by a few millimetres of metal or an equivalent amount of plastic.
Neutrons are more penetrating and so are potentially more dangerous. They cause damage by being captured by the nucleus of an atom. This can cause the atom to break in two fission or undergo another decay process known as transmutation. In either case, the original atom say a nitrogen atom is changed to become a different type of atom in this case, carbon The new atom will have different chemical properties and therefore could act as a poison , or for building materials change their physical properties.
Neutrons are either slowed down or captured safely by materials such as graphite or compounds containing lots of hydrogen such as tap water! All of these forms of radioactivity and radiation are naturally occurring. The difference is that radioisotopes are very unstable and contain high levels of nuclear energy and emit this energy in the form of nuclear radiation. Main difference: Isotopes can be stable or unstable, but Radioisotopes are always unstable. What is the difference between an isotope and a radioisotope?
Chemistry Matter Isotopes. Sam S. Nov 3, Advertisement Hide. Radioactivity and Radioisotopes. Chapter First Online: 28 July This process is experimental and the keywords may be updated as the learning algorithm improves. This is a preview of subscription content, log in to check access.
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