New York Codes, Rules and Regulations › Title 10 - DEPARTMENT OF HEALTH › Chapter I - State Sanitary Code › Part 16 - Ionizing Radiation › Radiation Equipment › Section 16.59 - Use of Computed Tomography Equipment

Current through Register Vol. 46, No. 28, July 10, 2024
(a) Definitions
(1) "Computed tomography (CT)" scan and
				  "computerized axial tomography (CAT)" scan refer to an imaging procedure that
				  uses x-rays to create cross-sectional images of the human body.
(2) "Computed tomography dose index" (CTDI)
				  means the integral of the dose profile along a line perpendicular to the
				  tomographic plane divided by the product of the nominal tomographic section
				  thickness and the number of tomograms produced in a single scan where the dose
				  profile is centered around z = 0 and for a multiple tomogram system, the scan
				  increment between adjacent scans is nT;
Click to view
					 image
z = position along a line perpendicular to the tomographic
					 plane;
D (z) = Dose at position z;
T = Nominal tomographic section thickness;
n = Number of tomograms produced in a single scan
(3) "CT x-ray system" is
				  technology that is used to perform CT scans and includes but is not limited to,
				  a control panel, image display device, gantry, x-ray tube, collimating device
				  with filters, high voltage transformer and a data acquisition system.
(4) "CT scanner" refers to technology used to
				  perform and interpret CT scans and includes, but is not limited to, a control
				  panel, gantry, high voltage generator, x-ray tube, table and display devices
				  that are used for image interpretation.
(5) "CTDI100" is the
				  dose measurement made with a 16cm diameter (head/pediatric body) or a 32cm
				  diameter (body) acrylic phantom. The measurements are made utilizing a 100mm
				  long pencil ionization chamber. Readings are made with the ion chamber in both
				  the center (axial or central dose) position and near surface slots of the
				  phantom (the peripheral dose).
(6)
				  "CTDIw", the weighted or blended dose, is calculated by
				  adding together two-thirds of the CTDI100 peripheral
				  dose with one-third of the CTDI100 axial or center dose.
				  (CTDIw = 2/3 CTDI100 peripheral +
				  1/3 CTDI100 axial or center). CTDIw represents an
				  average dose in the x and y planes.
(7) "CTDIvol"
				  represents the integrated dose over the total volume that is irradiated,
				  CTDIvol = (1/PITCH) x (CTDIw),
				  where "Pitch" is defined as the table travel per rotation divided by the
				  collimation of the x-ray beam. CTDIvol represents the
				  average dose in the x, y and z planes.
(8) "CT conditions of operation" means all
				  selectable parameters governing the operation of a CT x-ray system including
				  nominal tomographic section thickness, filtration, and the technique
				  factors.
(9) "CT dosimetry phantom"
				  means the phantom used for determination of the dose delivered by a CT x-ray
				  system. The phantom shall be a right circular cylinder of
				  polymethyl-methacrylate of density 1.19±0.01 grams per cubic centimeter. The
				  phantom shall be at least 14 centimeters in length and shall have diameters of
				  32.0 centimeters for testing any CT system designed to image any section of the
				  body (whole body scanners) and 16.0 centimeters for any system designed to
				  image the head (head scanners) or for any whole body scanner operated in the
				  head scanning mode. The phantom shall provide means for the placement of a
				  dosimeter(s) along its axis of rotation and along a line parallel to the axis
				  of rotation 1.0 centimeter from the outer surface and within the
				  phantom.
(10) "Dose length product"
				  (DLP) is defined as the CTDIvol times the irradiated
				  length of the body for the whole series of images that are taken during a CT
				  scan.
(11) "Picture Archiving and
				  Communication System (PACS)" is a medical imaging technology that provides
				  access to and storage for medical images from multiple modalities. It is
				  comprised of an image acquisition system, display, network and data storage or
				  archiving system.
(12) "Reference
				  plane" means a plane which 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 or a series of 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 such
				  displacement.
(15) "Technique"
				  means the settings selected on the control panel of the equipment and may
				  include the position of the x-ray tube, image intensifier and
				  patient.
(16) "Technique chart"
				  means a chart that lists the standard settings and positions for a given
				  technique.
(17) "Tomogram" is an
				  image of a tissue plane or section of tissue.
(18) "Tomographic plane" means that geometric
				  plane which the manufacturer 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.