CT number

(redirected from Hounsfield number)


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) (NA) 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.

CT num·ber

a normalized value of the calculated x-ray absorption coefficient of a pixel (picture element) in a computed tomogram, expressed in Hounsfield units, where the CT number of air is -1000 and that of water is 0.
Synonym(s): Hounsfield number


Godfrey N., English electronics engineer and Nobel laureate, 1919–.
Hounsfield number - a normalized value of the calculated x-ray absorption coefficient of a pixel in a computed tomogram. Synonym(s): CT number
Hounsfield unit - a normalized index of x-ray attenuation used in CT imaging.
References in periodicals archive ?
This technique is widely used to create a three dimensional model and to assign the density of the bone according to the grayscale or Hounsfield number (HU) [8-9].
The gray level intensity of a pixel in a CT image is determined by the Hounsfield number [6].
CT Hounsfield numbers of soft tissues on unenhanced abdominal CT scans: Variability between two different manufacturers' MDCT scanners.
CT Hounsfield Numbers. To compare the visual difference of foam contrast agent and conventional contrast media (Ultravist 300; Schering AG, Berlin, Germany), we measured CT Hounsfield unit (HU) of pure and half diluted conventional contrast agent and foam contrast using a CT scanner (Inveon CT; Siemens Healthcare, Erlangen, Germany).
Quantity: Dismantling of old (defective) X-ray tube, followed by its recovery and sent to the producer - 1 mechanical installation of new X-ray tube (including the tube) - 1, cleaning and lubrication of high-voltage connectors on the cable - 1 mechanical JUstirovka block radiator and block detectors in the axial plane - 1, the procedure termotrenuvannya tube - 1, the adjustment focus position of the radiator and the wedge filter izotsentru relative rotation - 1, perform system calibration - 1, the procedure of correction scale Hounsfield numbers - 1.