6 Colo. Code Regs. § 1007-1-6.2
As used in Part 6, these terms have the definitions set forth as follows:
"AAPM Online Report 03" means "Assessment of Display Performance for Medical Imaging Systems", AAPM Online Report No. 03 by Task Group 18 of the American Association of Physicists in Medicine (April 2005).
"AAPM Report 96" means "The Measurement, Reporting, and Management of Radiation Dose in CT", AAPM Report No. 96 by Task Group 23 (CT Dosimetry) of the Radiography and Fluoroscopy Subcommittee of the Diagnostic Imaging Council CT Committee of the American Association of Physicists in Medicine (January 2008).
"Alert value" means a dose index that is set by the registrant to trigger an alert to the CT operator prior to scanning within an ongoing examination. The alert value represents a universal dose index value well above the registrant's established range for the examination that warrants more stringent review and consideration before proceeding.
"Aluminum equivalent" means the thickness of aluminum (type 1100 alloy with a nominal chemical composition of aluminum 99.00 percent minimum and copper 0.12 percent maximum) affording the same attenuation, under specified conditions, as the material in question.
"Articulated joint" means a joint between two separate sections of a tabletop which joint provides the capacity of one of the sections to pivot on the line segment along which the sections join.
"Attenuation block" means a block or stack of type 1100 aluminum alloy, or aluminum having equivalent attenuation, with dimensions 20 centimeters (cm) or larger by 20 cm or larger by 3.8 cm, that is large enough to intercept the entire x-ray beam.
"Automatic exposure control" (AEC) means a device which automatically controls one or more technique factors in order to obtain at the pre-selected location(s) a required quantity of radiation.
"Automatic exposure rate control" (AERC) means a device that automatically controls one or more technique factors in order to obtain at the pre-selected location(s) a required quantity of radiation per unit time.
"Automatic film processor" means a device that produces an image from a film-screen system in mechanical steps with limited human intervention.
"Barrier". See "protective barrier".
"Beam axis" means, for purposes of Part 6, a line from the source through the center of the x-ray field.
"Beam-limiting device" means a device that provides a means to restrict the dimensions of the x-ray field.
"Bone densitometry" means a noninvasive measurement of certain physical characteristics of bone that reflect bone strength. Test results are typically reported as bone mineral content or density and are used for diagnosing osteoporosis, estimating fracture risk, and monitoring changes in bone mineral content.
"Bone densitometer" means a device intended for medical purposes to measure bone density and mineral content by x-ray or gamma ray transmission measurements through the bone and adjacent tissues. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories. A bone densitometer is synonymous with dual-energy x-ray absorptiometry (DXA) systems.
"C-arm fluoroscope" means a fluoroscopic x-ray system in which the image receptor and the x-ray tube housing assembly are connected or coordinated to maintain a spatial relationship. Such a system allows a change in the direction of the beam axis with respect to the patient without moving the patient.
"Cantilevered tabletop" means a tabletop designed such that the unsupported portion can be extended at least 100 cm beyond the support.
"Cassette holder" means a device, other than a spot-film device, that supports and/or fixes the position of the image receptor during a radiographic exposure.
"Cephalometric" means imaging equipment or methods that are used for the radiographic visualization and measurement of the dimensions of the human head.
"Coefficient of variation" (C) means the ratio of the standard deviation to the mean value of a population of observations. It is estimated using the following equation:
"Computed radiography" (CR). See "photostimulable storage phosphor system."
"Computed tomography" (CT) means the production of a tomogram by the acquisition and computer processing of x-ray transmission data.
"Cone Beam Computed Tomography (CBCT)" means a volumetric imaging modality that uses a two-dimensional digital flat-panel detector to yield a three dimensional volumetric image in one rotation. Reconstruction algorithms can be used to generate images of any desired plane.
"Control panel" means that part of the x-ray control upon which are mounted the switches, knobs, pushbuttons, keypads, touchscreens, and other hardware or software necessary for the operator to manually select exposure settings.
"Cradle" means:
"CT" (see "computed tomography").
"CT conditions of operation" means all selectable parameters governing the operation of a CT x-ray system including, but not limited to, nominal tomographic section thickness, filtration, and the technique factors as defined in 6.2.
"CT gantry" means the tube housing assemblies, beam-limiting devices, detectors, and the supporting structures, frames, and covers which hold and/or enclose these components within a computed tomography system.
"CT number" means the number used to represent the x-ray attenuation associated with each elemental area of the CT image where:
"Dead-man switch" means a switch so constructed that a circuit-closing contact can be maintained only by continuous pressure on the switch by the operator.
"Detector" (See "Radiation detector")
"Diagnostic source assembly" means the tube housing assembly with a beam-limiting device attached.
"Diagnostic x-ray system" means an x-ray system designed for irradiation of any part of the human or animal body for the purpose of diagnosis or visualization.
"Digital radiography" (DR) means an x-ray imaging method (or radiography) which produces a digital rather than analog image. DR includes both computed radiography and direct digital radiography.
"Direct digital radiography" (DDR; also see CR and DR) means an x-ray imaging method in which a digital sensor is used to capture an x-ray image.
"Dose area product (DAP) (aka kerma-area product (KAP))" means the product of the air kerma and the area of the irradiated field and is typically expressed in Gy-cm2, so it does not change with distance from the x-ray tube.
"Dose profile" means the dose as a function of position along a line.
"Equipment". See "x-ray equipment".
"Examination" means performing a procedure, including selection of exposure settings, positioning the x-ray system and the patient, and initiating and terminating the exposure.
"Facility", for mammography (to supplement the Part 1 meaning of "facility"), means a hospital, outpatient Department, clinic, radiology practice, mobile unit, office of a physician, or other facility that conducts mammography activities, including the following: operation of equipment to produce a mammogram, initial interpretation of the mammogram, and maintaining viewing conditions for that interpretation.
"Field emission equipment" means equipment that uses an x-ray tube in which electron emission from the cathode is due solely to the action of an electric field.
"Filter" means material placed in the useful beam to preferentially absorb selected radiations.
"Floor plan" means, for purposes of Part 6, a plan view of the overall layout to scale of a room or group of rooms, including the location and configuration of any radiation producing machines in each room.
"Fluoroscopic imaging assembly" means a subsystem in which x-ray photons produce a set of fluoroscopic images or radiographic images recorded from the fluoroscopic image receptor. It includes the image receptor(s), electrical interlocks, if any, and structural material providing linkage between the image receptor and diagnostic source assembly.
"Fluoroscopic irradiation time" means the cumulative duration during an examination or procedure of operator-applied continuous pressure to the device, enabling x-ray tube activation in any fluoroscopic mode of operation.
"Fluoroscopically-Guided Interventional (FGI) Procedures" means an interventional diagnostic or therapeutic procedure performed via percutaneous or other access routes, usually with local anesthesia or intravenous sedation, which uses external ionizing radiation in the form of fluoroscopy to localize or characterize a lesion, diagnostic site, or treatment site, to monitor the procedure, and to control and document therapy.
"FGI Procedures Committee" means the representative group of individuals in a FGI facility responsible for the ongoing review and management of FGI procedures to ensure that exams being performed achieve the desired diagnostic image quality at the lowest radiation dose possible while properly exploiting the capabilities of the equipment being used.
"Fluoroscopy" means a technique for generating x-ray images and presenting them simultaneously and continuously as visible images.
"Focal spot (actual)" means the area projected on the anode of the x-ray tube bombarded by the electrons accelerated from the cathode and from which the useful beam originates.
"General purpose radiographic x-ray system" means any radiographic x-ray system which, by design, is not limited to radiographic examination of specific anatomical regions.
"Half-value layer" (HVL) means the thickness of specified material which attenuates the beam of radiation to an extent such that the air kerma rate (AKR) is reduced by one-half of its original value. In this definition, the contribution of all scattered radiation, other than any which might be present initially in the beam concerned, is deemed to be excluded.
"Hand-held x-ray equipment" means a type of portable x-ray equipment that is designed to be held in the operators hand during operation. See "x-ray equipment".
"Healing arts screening" means, for purposes of these regulations, the testing or evaluation resulting in the exposure of any human being to an x-ray machine for the detection or evaluation of health indications when such a test is not specifically and individually ordered by a licensed physician, chiropractor, dentist, podiatrist or other person legally authorized to prescribe such a test for the purpose of diagnosis or treatment.
"Heat unit" means a unit of energy equal to the product of the peak kilovoltage, milliamperes, and seconds (kVp- mA- second).
"HVL". See "half-value layer".
"Image intensifier" means a device, installed in its housing, that instantaneously converts an x-ray pattern into a corresponding visible light image and electronically amplifies the brightness of that visible image.
"Image receptor" means any device, such as a fluorescent screen, radiographic film, x-ray image intensifier tube, photostimulable phosphor, or solid-state or gaseous detector that transforms incident x-ray photons either into a visible image or into another form that can be made into a visible image by further transformations. In those cases where means are provided to preselect a portion of the image receptor, the term "image receptor" shall mean the preselected portion of the device.
"Isocenter" means the center of the smallest sphere through which the beam axis passes when the equipment moves through a full range of rotations about its common center.
"Kerma-area product (KAP)". See "Dose area product"
"Kilovolts peak". See "Peak tube potential".
"kV" means kilovolt.
"kVp". See "Peak tube potential".
"kWs" means kilowatt-second.
"Last image hold radiograph" (LIH) means an image obtained either by retaining one or more fluoroscopic images, which may be temporarily integrated, at the end of a fluoroscopic exposure.
"Lead equivalent" means the thickness of lead affording the same attenuation, under specified conditions, as the material in question.
"Leakage radiation" means radiation emanating from the diagnostic source assembly except for:
"Leakage technique factors" means the technique factors associated with the diagnostic source assembly which are used in measuring leakage radiation. They are defined as follows:
"Light field" means that area of the intersection of the light beam from the beam-limiting device, and one of the set of planes parallel to, and including, the plane of the image receptor, whose perimeter is the locus of points, at which the illumination is one-fourth of the maximum in the intersection.
"Mammogram" means a radiographic image produced through mammography.
"Mammography" means radiography of the breast, but for purposes of this part, does not include:
"Mammography phantom" means a test object used to simulate radiographic characteristics of compressed breast tissue and containing components that radiographically model aspects of breast disease and cancer.
"Manual film developing" means a way to produce an image that requires human intervention to move the film from developer to fixer to wash.
"mAs" means milliampere-seconds (mAs), a measure of electrical current produced over a set amount of time via an x-ray tube.
"Mobile x-ray equipment". See "x-ray equipment".
"Mode of operation" means, for fluoroscopic systems, a distinct method of fluoroscopy, or radiography provided by the manufacturer and selected with a set of several technique factors or other control settings uniquely associated with the mode.
"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.
"NCRP Report 147" means National Council on Radiation Protection and Measurements Report No. 147, "Structural Shielding Design For Medical Imaging Facilities" (November 2004).
"Noise" in CT means the standard deviation of the fluctuations in CT number expressed as a percentage of the attenuation coefficient of water. Its estimate (Sn) is calculated using the following expression:
"Nominal tomographic section thickness" means the measured 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.
"Notification value" means a protocol-specific dose index that is set by the registrant to trigger a notification to the CT operator prior to scanning when the dose index exceeds the established range for the examination.
"Optical Density" (OD) equals log (1/transmittance), where the transmittance of the film is the fraction of incident light transmitted by the film.
"Patient" means a human being or an animal to whom machine-produced radiation is delivered for healing arts examination, screening, diagnosis, or treatment.
"PBL". See "positive beam limitation".
"Peak tube potential" means the maximum value of the potential difference across the x-ray tube during an exposure.
"Photostimulable storage phosphor" (PSP) means a material used to capture and store radiographic images in computed radiography systems.
"Picture element" (pixel) means an elemental area of a digitally acquired image.
"PID". See "position indicating device".
"Pitch" means the table incrementation, in CT, per x-ray tube rotation, divided by the nominal x-ray beam width at isocenter.
"Portable x-ray equipment". See "x-ray equipment".
"Position indicating device" (PID) means a device on dental x-ray equipment used to indicate the beam position and to establish a definite source-surface (skin) distance, without regard to whether the device incorporates or serves as a beam-limiting device.
"Positive beam limitation" (PBL) means the automatic or semi-automatic adjustment of an x-ray beam to the size of the selected image receptor, whereby exposures cannot be made without such adjustment.
"Primary protective barrier" means the material, excluding filters, placed to attenuate the useful beam for radiation protection purposes.
"Protective apparel" means a garment made of radiation-absorbing materials used to reduce radiation exposure to the wearer.
"Protective barrier" means a barrier of radiation absorbing material(s) used to reduce radiation exposure.
"Protocol" means a collection of settings and parameters that fully describe an examination.
"Pulsed mode" means operation of a fluoroscopic x-ray system such that the x-ray tube current is pulsed by the x-ray control to produce one or more exposure intervals of duration less than one-half second.
"Qualified inspector (QI)" is as defined in Section 2.2 of Part 2 of these regulations.
"Qualified trainer" is as defined in Section 2.2 of Part 2 of these regulations.
"Quality assurance (QA)" means a written monitoring and verification program which uses testing, auditing and inspection to ensure that deficiencies, deviations, defective equipment, or unsafe practices, or a combination thereof, relating to the use, disposal, management, or manufacture of radiation devices are identified, promptly corrected, and reported to the department where required.
"Radiation detector" means a device which in the presence of radiation provides a signal or other indication suitable for use in measuring one or more quantities of incident radiation.
"Radiation Protocol Committee (RPC)" means the representative group of individuals in a CT facility responsible for the ongoing review and management of CT protocols to ensure that exams being performed achieve the desired diagnostic image quality at the lowest radiation dose possible while properly exploiting the capabilities of the equipment being used.
"Radiation therapy simulation system" means a radiographic or fluoroscopic x-ray system or a computed tomography system intended for localizing the volume to be exposed during radiation therapy and confirming the position and size of the therapeutic irradiation field.
"Radiograph" means an image created directly or indirectly by x-rays resulting in a permanent visible image on film or digital record.
"Radiography" means a technique for generating and recording an x-ray pattern for the purpose of providing the user with the image(s) after termination of the exposure.
"Reference plane" means a plane which is parallel to and which can be offset (as specified in manufacturer information provided to users) from the location of the tomographic plane(s).
"Registered medical physicist (RMP)" is as defined in Section 2.2 of Part 2 of these regulations.
"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.
"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.
"Scan sequence" means a pre-selected set of two or more scans performed consecutively under preselected CT conditions of operation.
"Scan time" means the time elapsed during the accumulation of x-ray transmission data for a single scan.
"Scatter radiation" means ionizing radiation that, during passage through matter, has been deviated in direction.
"Sensitivity profile" means the relative response of the CT x-ray system as a function of position along a line perpendicular to the tomographic plane.
"Shutter" means a device attached to the tube housing assembly that can intercept the entire cross sectional area of the useful beam and that has a lead equivalency not less than that of the tube housing assembly.
"SID". See "source-image receptor distance".
"Single tomogram system" means a CT x-ray system which obtains x-ray transmission data during a scan to produce a single tomogram.
"Size-specific dose estimate (SSDE)" means a patient dose estimate which takes into consideration corrections based on the size of the patient, using linear dimensions measured on the patient or patient images.
"Source" means the focal spot of the x-ray tube.
"Source-image receptor distance" (SID) means the distance from the source to the center of the input surface of the image receptor.
"Source-skin distance" (SSD) means the distance from the source to the center of the entrant x-ray field in the plane tangent to the patient skin surface.
"Spot image" means a radiograph that is made during a fluoroscopic examination to permanently record conditions that exist during that fluoroscopic procedure.
"Spot-image device" means a device intended to transport and/or position a radiographic image receptor between the x-ray source and fluoroscopic image receptor. It includes a device intended to hold a cassette over the input end of the fluoroscopic image receptor for the purpose of producing a radiograph. A spot-film device is an older type of spot-image device.
"SSD". See "source-skin distance".
"Stationary x-ray equipment". See "x-ray equipment".
"Stray radiation" means the sum of leakage and scattered radiation.
"Substantial radiation dose level" (SRDL) means an appropriately-selected reference value used to trigger additional dose-management actions during a procedure and medical follow-up for a radiation level that might produce a clinically-relevant injury in an average patient. There is no implication that radiation levels above an SRDL will always cause an injury or that radiation levels below an SRDL will never cause an injury.
"Technique factor" means an exposure control setting that specifies the peak tube potential in kV and
"The Report of AAPM Task Group 270" means the report on Display Quality Assurance issued by the American Association of Physicists in Medicine (AAPM), January 2019.
"Tomogram" means the depiction of the x-ray attenuation properties of a section through the body.
"Tomographic plane" means that geometric plane that is identified as corresponding to the output tomogram.
"Tomographic section" means the volume of an object whose x-ray attenuation properties are imaged in a tomogram.
"Tube" means an x-ray tube, unless otherwise specified.
"Tube housing assembly" means the tube housing with tube installed, including high-voltage and/or filament transformers and other appropriate elements when such are contained within the tube housing.
"Useful beam" means the radiation which passes through the tube housing port and the aperture of the beam limiting device when the exposure switch or timer is activated.
"Visible area" means that portion of the input surface of the image receptor over which incident x-ray photons are producing a visible image.
"Volumetric dental imaging system" means an x-ray machine that produces, for oral and maxillofacial structures, a three-dimensional tomographic data set or a time sequence of three-dimensional tomographic data sets. A dental x-ray machine only capable of producing a two-dimensional image is not considered to be a volumetric dental imaging system.
"X-ray control" means a device which controls input power to the x-ray high-voltage generator and/or the x-ray tube. It includes equipment such as timers, phototimers, automatic brightness stabilizers, and similar devices, which control the technique factors of an x-ray exposure.
"X-ray exposure control" means a device, switch, button or other similar means by which an operator initiates and/or terminates the radiation exposure. The x-ray exposure control may include such associated equipment as timers and back-up timers.
"X-ray equipment" means an x-ray system, subsystem, or component thereof. Types of x-ray equipment are as follows:
"X-ray field" means that area of the intersection of the useful beam and any one of the set of planes parallel to and including the plane of the image receptor, whose perimeter is the locus of points at which the air kerma rate is one-fourth of the maximum in the intersection.
"X-ray high-voltage generator" means a device that transforms electrical energy from the potential supplied by the x-ray exposure control to the tube operating potential. The device may also include means for transforming alternating current to direct current, filament transformers for the x-ray tube(s), high-voltage switches, electrical protective devices, and other elements.
"X-ray imaging system" or "x-ray system" means an assemblage of components for the controlled production of x-rays.
"X-ray table" means a patient support device with its patient support structure (tabletop) interposed between the patient and the image receptor or x-ray tube during radiography and/or fluoroscopy. This includes, but is not limited to, any stretcher equipped with a radiolucent panel and any table equipped with a cassette tray (or Bucky), cassette tunnel, fluoroscopic image receptor, or spot-image device beneath the tabletop.
"X-ray tube" means any electron tube that is designed to be used primarily for the production of x-rays.
"X-ray system". See "x-ray imaging system".
6 CCR 1007-1-6.2