CT number definition

CT number means the number used to represent the x-ray attenuation associated with each elemental area of the CT image.

CT number or “CTN” means the number used to repre- sent the x−ray attenuation associated with each elemental area of the CT image as expressed in the following equation:

CT number means the number used to represent the X-ray attenuation associated with each elemental area of the CT image. where:k = A constant. (The constant has a normal value of 1,000 when the Houndsfield scale of CTN is used.)µx = Linear attenuation coefficient of the material of interest.µw = Linear attenuation coefficient of water.

Examples of CT number in a sentence

• OR  Vendor or Contractor is registered with the California Registry of Charitable Trusts under the CT number listed above and is in compliance with its registration and reporting requirements under California law.

• Invoices shall include the following information: CT number, Contractor name and/or DBA, Contractor address, number of hours worked, dates of work, rate, and detailed description of service/materials provided.

• OR Vendor or Contractor is registered with the California Registry of Charitable Trusts under the CT number listed above and is in compliance with its registration and reporting requirements under California law.

• This procedure is recommended to be used by a physicist at the vendor origin or at an imaging site, to insure product qualification for a CT scanner in terms of linearity and repeatability of the measurement of CT number for air, lung equivalent foam, and water standards.For the minimum standard, the following procedure can be followed for image acquisition:1.

• The phantom measured 300 × 200 × 100 mm in the x- y- and z-dimensions and was composed of urethane rubber, which has a CT number of −5 HU, similar to that of water, at 120 kVp. Polystyrene foam inserts were used to simulate the lungs, and a calcium-doped urethane rubber insert was used to simulate the spine.

More Definitions of CT number

CT number or "CTN" means the number used to represent the x-ray attenuation associated with each elemental area of the CT image as expressed in the following equation:

CT number means the number used to represent the X-ray attenuation associated with each elemental

CT number means the number used to represent the x-ray attenuation associated with each elemental area of the CT image:CTN = k(ux - uw)uwwhere:k = A constant, a normal value of 1,000 when the Houndsfield scale of CT number is used; ux = Linear attenuation coefficient of the material of interest;uw = Linear attenuation coefficient of water.

CT number. (CTN) means the number used to represent the x- ray attenuation associated with each elemental area of the CT image, as set forth in Appendix E.

CT number means the number used to represent the x-ray attenuation

CT number means the number used to represent the x-ray attenuation associated with each elemental area of the CT image. k( ux - uw)CTN = uw where:k = A constant, a normal value of 1,000 when the Houndsfield scale of CTN is used;ux= Linear attenuation coefficient of the material of interest; uw= Linear attenuation coefficient of water. 11. Dose profile means the dose as a function of position along a line. 12. Elemental area means the smallest area within a tomogram for which the x-ray attenuation properties of a body are depicted. (See also "Picture element"). 13. Modulation transfer function means the modulus of the Fourier transform of the impulse response of the system. 14. Multiple tomogram system means a computed tomography x-ray system which obtains x-ray transmission data simultaneously during a single scan to produce more than one tomogram. 15. Noise means the standard deviation of the fluctuations in CTN expressed as a percentage of the attenuation coefficient of water. Its estimate (sn) is calculated using the following expression: Sn = 100 x CS x suw where: CS = Linear attenuation coefficient of the material of interest. uw = Linear attenuation coefficient of water.s = Estimated standard deviation of the CTN of picture elements in a specified area of the CT image. 16. Nominal tomographic section thickness means the full width at half-maximum of the sensitivity profile taken at the center of the cross-sectional volume over which x-ray transmission data are collected. 17. Picture element means an elemental area of a tomogram. 18. Reference plane means a plane which is displaced from and parallel to the tomographic plane. 19. Remanufacturing means modifying a CT system in such a way that the resulting dose and imaging performance become substantially equivalent to any CT x-ray system manufactured by the original manufacturer on or after November 29, 1984. Any reference in this subsection to “manufacture,” “manufacturer,” or “manufacturing” includes remanufacture, remanufacturing, respectively. 20. Scan means the complete process of collecting x-ray transmission data for the production of a tomogram. Data can be collected simultaneously during a single scan for the production of one or more tomograms. 21. Scan increment means the amount of relative displacement of the patient with respect to the CT system between successive scans measured along the direction of such displacement. 22. Scan sequence means a pre-selected set of two or more scans performed consec...

CT number means the number usedto represent the x-ray attenuation as- sociated with each elemental area of the CT image.