Utah Administrative Code
Topic - Environmental Quality
Title R313 - Waste Management and Radiation Control, Radiation
Rule R313-28 - Use of X-Rays in the Healing Arts
Section R313-28-20 - Definitions
As used in R313-28, the following definitions apply:
"Accessible surface" means the external surface of the enclosure or housing provided by the manufacturer.
"Actual focal spot" refer to "Focal spot."
"Aluminum equivalent" means the thickness of aluminum, type 1100 alloy, affording the same attenuation, under specified conditions, as the material in question. The nominal chemical composition of type 1100 aluminum alloy is 99.00 percent minimum aluminum, 0.12 percent copper.
"Assembler" means individuals engaged in the business of assembling, replacing, or installing one or more components into an x-ray system or subsystem. The term includes the owner of an x-ray system or his or her employee or agent if they assemble components into an x-ray system that is subsequently used to provide professional or commercial services.
"Attenuation block" means a block or stack, having appropriate dimensions 20 cm by 20 cm by 3.8 cm, of type 1100 aluminum alloy or other materials having equivalent attenuation.
"Automatic EXPOSURE control" means a device which automatically controls one or more technique factors in order to obtain, at a preselected location, a required quantity of radiation. Phototimer and ion chamber devices are included in this category.
"Barrier" refer to "Protective barrier".
"Beam axis" means a line from the source through the centers of the x-ray fields.
"Beam-limiting device" means a device which provides a means to restrict the dimensions of the x-ray field.
"Certified components" means components of x-ray systems which are subject to regulations promulgated under Public Law 90-602, the Radiation Control for Health and Safety Act of 1968.
"Certified system" means an x-ray system which has one or more certified components.
"Changeable filters" means filters designed to be removed by the operator.
"Coefficient of variation (C)" means the ratio of the standard deviation to the mean value of a population of observations.
"Computed tomography" means the production of a tomogram by the acquisition and computer processing of x-ray transmission data.
"Control panel" means that part of the x-ray control upon which are mounted the switches, knobs, push buttons, and other hardware necessary for setting the technique factors.
"Cooling curve" means the graphical relationship between heat units stored and cooling time.
"CT" means computed tomography.
"CT gantry" means the tube housing assemblies, beam-limiting devices, detectors, and the supporting structures and frames which house these components.
"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.
"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 part of the human body for the purpose of recording or visualization for diagnostic purposes.
"Entrance EXPOSURE rate" means the EXPOSURE free in air per unit time at the point where the useful beam enters the patient.
"Equipment" refer to "X-ray equipment".
"Field emission equipment" means equipment which 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 absorb preferentially selected radiations.
"Fluoroscopic imaging assembly" means a subsystem in which x-ray photons produce a fluoroscopic image. It includes equipment housing, electrical interlocks, the primary protective barrier, and structural material providing linkage between the image receptor and the diagnostic source assembly.
"Focal spot" means the area on the anode of the x-ray tube bombarded by the electrons accelerated from the cathode and from which the useful beam originates. Also referred to as "Actual focal spot."
"Gonad shield" means a protective barrier for the testes or ovaries.
"Half-value layer or HVL" means the thickness of specified material which attenuates the beam of radiation to an extent that the EXPOSURE rate is reduced to one-half of its original value. In this definition, the contribution of scatter radiation, other than that which might be present initially in the beam concerned, is deemed to be excluded.
"Healing arts screening" means the use of x-ray equipment to examine individuals who are asymptomatic for the disease for which the screening is being performed and the use of x-rays are not specifically and individually ordered by a licensed practitioner of the healing arts legally authorized to order x-ray tests for the purpose of diagnosis.
"Heat unit" means a unit of energy equal to the product of the peak kilovoltage, milliamperes, and seconds: for example, kVp times mA times seconds.
"HVL" refer to "half value layer."
"Image intensifier" means a device installed in its housing which instantaneously converts an x-ray pattern into a light image of higher energy density.
"Image receptor" means a device, for example, a fluorescent screen radiographic film, solid state detector, or gaseous detector, which transforms incident x-ray photons to produce a visible image or stores the information in a form which can be made into a visible image. 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.
"Irradiation" means the exposure of matter to ionizing radiation.
"Kilovolts peak" refer to "Peak tube potential".
"kV" means kilovolts.
"kVp" refer to "Peak tube potential."
"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:
(a) the useful beam, and
(b) radiation produced when the exposure switch or timer is not activated.
"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:
(a) For diagnostic source assemblies intended for capacitor energy storage equipment, the maximum- rated peak tube potential and the maximum-rated number of exposures in an hour for operation at the maximum-rated peak tube potential with the quantity of charge per exposure being ten millicoulombs, ten milliampere seconds, or the minimum obtainable from the unit, whichever is larger.
(b) For diagnostic source assemblies intended for field emission equipment rated for pulsed operation, the maximum-rated peak tube potential and the maximum-rated number of x-ray pulses in an hour for operation at the maximum-rated peak tube potential.
(c) For other diagnostic source assemblies, the maximum-rated peak tube potential and the maximum- rated continuous tube current for the maximum-rated peak tube potential.
"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.
"mA" means tube current in milliamperes.
"mAs" means milliampere second or the product of the tube current in milliamperes and the time of exposure in seconds.
"Mammography imaging medical physicist" means an individual who conducts mammography surveys of mammography facilities.
"Mammography survey" means an evaluation of x-ray imaging equipment and oversight of a mammography facility's quality control program.
"Mobile x-ray equipment" refer to "X-ray equipment".
"Multiple scan average dose" means the average dose at the center of a series of scans, specified at the center of the axis of rotation of a CT x-ray system.
"New installation" means change, modification or relocation of new or existing shielding or equipment.
"Operator of diagnostic x-ray equipment" means either:
(a) The individual responsible for insuring that the appropriate technique factors are set on the x-ray equipment, or
(b) The individual who makes the radiation exposure.
"Patient" means an individual subjected to healing arts examination, diagnosis, or treatment.
"PBL" refer to "Positive beam limitation."
"Peak tube potential" means the maximum value of the potential difference across the x-ray tube during an exposure.
"Phantom" means a volume of material behaving in a manner similar to tissue with respect to the attenuation and scattering of radiation.
"PID" refer to "Position indicating device."
"Portable x-ray equipment" refer to "X-ray equipment".
"Position indicating device (PID)" means a device, on dental x-ray equipment which indicates the beam position and establishes a definite source-surface (skin) distance. The device may or may not incorporate or serve as a beam-limiting device.
"Positive beam limitation" 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 beam scatter" means scattered radiation which has been deviated in direction or energy by materials irradiated by the primary beam.
"Primary protective barrier" refer to "Protective barrier".
"Protective apron" means an apron made of radiation absorbing materials, used to reduce radiation exposure.
"Protective barrier" means a barrier of radiation absorbing material used to reduce radiation exposure.
(a) "Primary protective barrier" means the material, excluding filters, placed in the useful beam to reduce the radiation exposure for protection purposes.
(b) "Secondary protective barrier" means the material which attenuates stray radiation.
"Protective glove" means a glove made of radiation absorbing materials used to reduce radiation exposure.
"Radiation therapy simulation system" means a radiographic or fluoroscopic x-ray system intended for localizing the volume to be exposed during radiation therapy and for confirming the position and size of the therapeutic irradiation field.
"Radiograph" means an image receptor on which the image is created directly or indirectly by an x-ray pattern and results in a permanent record.
"Rating" means the operating limits of an x-ray system or subsystem as specified by the component manufacturer.
"Recording" means producing a permanent form of an image resulting from x-ray photons.
"Reference plane" means a plane which is displaced from and parallel to the tomographic plane.
"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 computer tomographic x-ray system between successive scans measured along the direction of such displacement.
"Scattered radiation" means radiation that, during passage through matter, has been deviated in direction, energy or both direction and energy. Also refer to "Primary Beam Scatter".
"Shutter" means a device attached to the tube housing assembly which can intercept the entire cross sectional area of the useful beam and which has a lead equivalency at least that of the tube housing assembly.
"SID" refer to "Source-image receptor distance".
"Source" means the focal spot of the x-ray tube.
"Source to image receptor distance" means the distance from the source to the center of the input surface of the image receptor.
"Special purpose x-ray system" means that which is designed for irradiation of specific body parts.
"Spot film" means a radiograph which is made during a fluoroscopic examination to permanently record conditions which exist during that fluoroscopic procedure.
"Spot film device" means a device intended to transport or position a radiographic image receptor between the x-ray source and fluoroscopic image receptor, including a device intended to hold a cassette over the input end of an image intensifier for the purpose of making a radiograph.
"SSD" means the distance between the source and the skin entrance plane of the patient.
"Stationary x-ray equipment" refer to "X-ray equipment".
"Stray radiation" means the sum of leakage and scattered radiation.
"Technique factors" means the following conditions of operation.
(a) For capacitor energy storage equipment, peak tube potential in kV and quantity of charge in mAs.
(b) For field emission equipment rated for pulsed operation, peak tube potential in kV and number of x-ray pulses.
(c) For other equipment, peak tube potential in kV and either;
(i) the tube current in mA and exposure time in seconds, or
(ii) the product of tube current and exposure time in mAs.
"Termination of irradiation" means the stopping of irradiation in a fashion which will not permit continuance of irradiation without the resetting of operating conditions at the control panel.
"Tomogram" means the depiction of the x-ray attenuation properties of a section through the body.
"Tomographic plane" means that geometric plane which 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. It includes high-voltage or filament transformers and other appropriate elements when they are contained within the tube housing.
"Tube rating chart" means the set of curves which specify the rated limits of operation of the tube in terms of the technique factors.
"Useful beam" means the radiation emanating from the tube housing port or the radiation head and passing through the aperture of the beam limiting device when the 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.
"X-ray exposure control" means a device, switch, button, or other similar means by which an operator initiates or terminates the radiation exposure. The x-ray exposure control may include associated equipment, for example, 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:
(a) "Mobile" means x-ray equipment mounted on a permanent base with wheels or casters for moving while completely assembled.
(b) "Portable" means x-ray equipment designed to be hand-carried.
(c) "Stationary" means x-ray equipment which is installed in a fixed location.
"X-ray field" means that area of the intersection of the useful beam and one of the sets of planes parallel to and including the plane of the image receptor, whose perimeter is the locus of points at which the EXPOSURE rate is one-fourth of the maximum in the intersection.
"X-ray high-voltage generator" means a device which transforms electrical energy from the potential supplied by the x-ray 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 high-voltage switches, electrical protective devices, and other appropriate elements.
"X-ray system" means an assemblage of components for the controlled production of x-rays. It includes minimally an x-ray high-voltage generator, an x-ray control, a tube housing assembly, a beam-limiting device, and the necessary supporting structures. Additional components which function with the system are considered integral parts of the system.
"X-ray tube" means an electron tube which is designed to be used primarily for the production of x- rays.
