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Beta radiation, consisting of electrons or positrons, is stopped by a thin aluminum plate, but gamma radiation requires shielding by dense material such as lead or concrete. [1] A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic ...
Background radiation is defined by the International Atomic Energy Agency as "Dose or the dose rate (or an observed measure related to the dose or dose rate) attributable to all sources other than the one (s) specified. [1] A distinction is thus made between the dose which is already in a location, which is defined here as being "background ...
These antibiotics all have a common element in their molecular structure: a four-atom ring known as a beta-lactam (β-lactam) ring. Through hydrolysis, the enzyme lactamase breaks the β-lactam ring open, deactivating the molecule's antibacterial properties. Beta-lactamases produced by gram-negative bacteria are usually secreted, especially ...
The production of beta particles is termed beta decay. They are designated by the Greek letter beta (β). There are two forms of beta decay, β − and β +, which respectively give rise to the electron and the positron. [8] Beta particles are much less penetrating than gamma radiation, but more penetrating than alpha particles.
Technetium-99m (99m Tc) is a metastable nuclear isomer of technetium-99 (itself an isotope of technetium), symbolized as 99m Tc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical radioisotope in the world. Technetium-99m is used as a radioactive tracer and can be detected in the ...
Positron emission tomography (PET) [1] is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for various imaging ...
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. [1][2] This includes: electromagnetic radiation consists of photons, such as visible radiation. particle radiation consists of particles of non-zero rest energy, such as beta radiation (β) acoustic radiation ...
Radionuclide. A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons ...