Kansas Administrative Regulations › Agency 28 - DEPARTMENT OF HEALTH AND ENVIRONMENT › Article 35 - RADIATION › Section 28-35-248a - Computed tomography (CT) X-ray systems

Current through Register Vol. 43, No. 28, July 11,
			 2024
(a) Definitions. In
			 addition to the definitions in part 1 of these regulations, the following
			 definitions shall be applicable to this regulation:
(1) "Computed tomography dose index" and
			 "CTDI" mean the integral from -7T to +7T of the dose profile along a line
			 perpendicular to the tomographic plane divided by the product of the normal
			 tomographic section thickness and the number of tomograms produced in a single
			 scan, as follows:
For Equation see Agnecy.
This definition assumes that the dose profile is centered
				around z=0 and that, for a multiple tomogram system, the scan increment between
				adjacent scans is nT.
(2)
			 "Contrast scale" and "CS" mean the change in the linear attenuation coefficient
			 per CTN relative to water, as follows:
For Equation see Agnecy.
(3) "CT conditions of operation" means all
			 selectable parameters governing the operation of a CT X-ray system including
			 nominal tomographic section thickness, filtration, and technique factors.
(4) "CT gantry" means the tube
			 housing assemblies, beam-limiting devices, and detectors and the supporting
			 structures and frames that hold these components.
(5) "CT number" and "CTN" mean the number
			 used to represent the X-ray attenuation associated with each elemental area of
			 the CT image, as follows:
For Equation see Agnecy.
(6) "Dose profile" means the dose as a
			 function of position along a line.
(7) "Elemental area" means the smallest area
			 within a tomogram for which the X-ray attenuation properties of a body are
			 depicted.
(8) "Multiple tomogram
			 system" means a computed tomography X-ray system that obtains X-ray
			 transmission data simultaneously during a single scan to produce more than one
			 tomogram.
(9) "Noise" means the
			 standard deviation of the fluctuations in CTN expressed as a percentage of the
			 attenuation coefficient of water. Noise is estimated using the following
			 equation:
For Equation see Agnecy.
(10) "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 the X-ray transmission data are
			 collected.
(11) "Picture element"
			 means an elemental area of a tomogram.
(12) "Reference plane" means a plane that is
			 displaced from and parallel to the tomographic plane.
(13) "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.
(14) "Scan
			 increment" means the amount of relative displacement of the patient with
			 respect to the CT X-ray system between successive scans measured along the
			 direction of the displacement.
(15) "Scan sequence" means a preselected set
			 of two or more scans performed consecutively under preselected CT conditions of
			 operation.
(16) "Scan time" means
			 the period of time between the beginning and the end of X-ray transmission data
			 accumulation for a single scan.
(17) "Single tomogram system" means a CT
			 X-ray system that obtains X-ray transmission data during a scan to produce a
			 single tomogram.
(18) "Tomographic
			 plane" means the geometric plane that is identified as corresponding to the
			 output tomogram.
(19) "Tomographic
			 section" means the volume of an object whose X-ray attenuation properties are
			 imaged in a tomogram.