CT number

CT number.

See Hounsfield unit.

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number [num´ber]

a symbol, as a figure or word, expressive of a certain value or a specified quantity determined by count.

atomic number (Z) a number expressive of the number of protons in an atomic nucleus, or the positive charge of the nucleus expressed in terms of the electronic charge.

Avogadro's number (N) (N_A) the number of molecules in one mole of a substance: 6.023 × 10²³. Called also Avogadro's constant.

CT number the density assigned to a voxel in a CAT scan on an arbitrary scale on which air has a density −1000; water, 0; and compact bone +1000. See also hounsfield unit.

mass number (A) the number of nucleons (protons plus neutrons) in the atom of a nuclide; generally indicated by a superscript preceding the symbol of a chemical element (e.g., ¹³¹I), denoting a specific isotope.

oxidation number a number assigned to each atom in a molecule or ion that represents the number of electrons theoretically gained (positive oxidation numbers) or lost (negative numbers) in converting the atom to the elemental form.

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CT

computed tomography.

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CT number

the density assigned to a voxel in a CT (computed tomography) scan on an arbitrary scale on which air has a density −1000; water, 0; and compact bone +1000. CT numbers are sometimes said to be expressed in 'Hounsfield units'.