1. In this Regulation, “aluminum equivalent” of a material means the thickness of aluminum (Aluminum Association Type 1100) that affords the same attenuation as the material where the aluminum and the material are irradiated under the same conditions; (“équivalence en aluminium”) “attenuation” means the decrease in radiation intensity caused by absorption and scattering of x-rays in a medium; (“atténuation”) “automatic exposure control” means a device that delivers a predetermined quantity of radiation to the image receptor by automatically controlling one or more technique factors; (“commande automatique d’exposition”) “average peak kilovoltage” means the maximum kilovoltage developed in a single pulse of voltage applied to the anode of an x-ray tube averaged over at least twelve successive pulses; (“tension de crête moyenne”) “backscatter” means radiation reaching a point from material located more distant from the x-ray source than the point; (“rétrodiffusion”) “beam limiting device” means a device that restricts the dimensions of the useful beam; (“dispositif de limitation du faisceau”) “cephalometric x-ray machine” means a dental x-ray machine that is used for the examination of the maxillofacial skeleton; (“appareil de radiographie céphalométrique”) “chiropodic x-ray machine” means an x-ray machine that is used for the examination of the foot; (“appareil de radiographie podologique”) “coefficient of variation” means the ratio of the estimated standard deviation to the mean value of a series of measurements calculated using the following equation:  where, Xi  = ith
measurement X̄ = mean value of the measurements S = estimated standard deviation n = number of measurements C = the coefficient of variation; (“coefficient de variation”) “control booth” means a defined area in which an x-ray worker operates an x-ray machine; (“cabine de commande”) “control panel” means that part of an x-ray machine that contains the switches, knobs, keys, buttons or other controls accessible to the x-ray operator that are used to set technique factors manually or automatically; (“tableau de commande”) “CT scanner” means an X-ray machine that is a computerized tomography system or subsystem and that is able to generate a volumetric representation of the human body using a multitude of X-rays at a multitude of orientations, and includes any such device regardless of its common name or brand name or any other way it is referred to, including, without limiting the generality of the foregoing, a computerized tomography scanner or a computerized axial tomography scanner; (“tomomètre”) “darkroom” means an enclosed space that is constructed to process light sensitive materials; (“chambre noire”) “density unit” means the relative amount of light transmitted through a processed film expressed on a common logarithmic scale; (“unité de densité”) “dental CT scanner” means a CT scanner that is used in the practice of dentistry and that is designed to produce images of the oral-facial complex only; (“scanographe dentaire”) “dental x-ray machine” means an x-ray machine that is used outside the mouth to examine teeth, jaws and related structures; (“appareil de radiographie dentaire”) “diagnostic x-ray machine” means an x-ray machine that is used for the examination of a human being but does not include a radiation therapy simulator or a computerized transaxial tomographic x-ray machine; (“appareil à rayons X pour usage diagnostique”) “dose equivalent” means a quantity that expresses on a common scale the energy absorbed by a small mass of a body irradiated by a beam of radiation weighted by a factor describing the biological effectiveness of the radiation concerned; (“équivalent de dose”) “filter” means material that is placed in the useful beam to attenuate preferentially the lower energy or a specific energy range of x-rays; (“filtre”) “fluoroscopic x-ray machine” means an x-ray machine, an image receptor and the equipment associated with the x-ray machine and the image receptor that is used in fluoroscopy; (“appareil fluoroscopique à rayons X”) “fluoroscopy” means a mode of x-ray exposure in which the image receptor and associated equipment produce and display a visible image that is viewed by the operator during or subsequent to the exposure; (“radioscopie”) “general-purpose radiographic x-ray machine” means a radiographic x-ray machine that is not limited by design or adaptation to radiographic examination of a specific anatomical region; (“appareil de radiographie à rayons X pour usage general”) “half-value layer” means the thickness of a specified material that attenuates the x-ray beam under conditions that minimize scattered radiation such that the exposure is reduced to one-half of its original value; (“couche de demi-atténuation”) “image receptor” means a device that converts incident x-radiation into a visible image or into a form that can be made into a visible image by further transformation; (“récepteur d’image”) “lead equivalent” of a material means the thickness of lead that affords the same attenuation as the material where the lead and the material are irradiated under the same conditions; (“équivalence en plomb”) “leakage radiation” means all the radiation except the useful beam that comes from within the housing of an energized x-ray tube or the radiation that is produced when the exposure switch or timer of an x-ray machine is not activated; (“rayonnement de fuite”) “light field” means the area of light at a specified plane that is directly outlined by a beam limiting device; (“champ lumineux”) “mammographic x-ray machine” means an x-ray machine that is used for the examination of the breast; (“mammographe”) “manual exposure control” means a device that is used by an x-ray operator to set technique factors in order to deliver a predetermined quantity of radiation to the image receptor; (“commande manuelle d’exposition”) “mean glandular breast dose” means the absorbed dose in milligrays averaged over the central volume of the breast, assuming .5 centimetre adipose tissue above and below the region of the central volume of the breast; (“dose glandulaire moyenne au sein”) “mobile x-ray machine” means an x-ray machine that can be moved from one location to another; (“appareil à rayons X mobile”) “occupancy” means the nature and extent of use of space adjacent to an x-ray machine; (“occupation”) “optical density” means the degree of opacity to visible light of a processed film expressed in density units; (“densité optique”) “out of province medical practitioner” means a person who is exempted from subsections 9 (1) and (3) of the Medicine Act, 1991 by a regulation made under that Act; (“médecin hors province”) “out of province registered nurse in the extended class” means a person who is exempted from subsections 11 (1) and (5) of the Nursing Act, 1991 by a regulation made under that Act and who holds, in another Canadian jurisdiction, the equivalent of a certificate of registration in the extended class for registered nurses in Ontario; (“infirmière autorisée ou infirmier autorisé de la catégorie supérieure hors province”) “panoramic x-ray machine” means a tomographic unit used for the production of radiographs of the teeth, jaws and related structures on a single film or radiograph; (“appareil de radiographie panoramique”) “patient entrance exposure” means the x-ray exposure, excluding exposure arising from back-scattered radiation, in the centre of an x-ray beam at the position of the surface of the patient that is closest to the x-ray source; (“exposition primaire du patient”) “phantom” means an object that simulates a patient when placed in an x-ray beam for the purpose of testing an x-ray machine or image receptor; (“fantôme”) “photofluorographic x-ray machine” means an x-ray machine that records photographically in reduced size the image produced on a fluorescent screen; (“appareil de radiographie photofluorographique”) “primary protective barrier” means a barrier that is sufficient to attenuate the useful beam to a specified degree; (“écran de protection primaire”) “protective accessory” means a device that is used to protect a person in an x-ray facility from receiving unnecessary radiation; (“accessoire de protection”) “registered nurse in the extended class” means a member of the College of Nurses of Ontario who is a registered nurse and who holds a certificate of registration in the extended class under the Nursing Act, 1991; (“infirmière autorisée ou infirmier autorisé de la catégorie supérieure”) “secondary protective barrier” means a barrier that is sufficient to attenuate stray radiation to a specified degree; (“écran de protection secondaire”) “stationary x-ray machine” means an x-ray machine that is installed permanently in one location and includes a machine that is permanently installed in a truck, bus, train or other movable facility; (“appareil à rayons X stationnaire”) “technique factors” means the following conditions of operation of a diagnostic x-ray machine that can be selected by the operator: 1. The peak tube potential. 2. The tube current. 3. The exposure time. 4. The added filtration. 5. A combination of the variables set out in paragraphs 1 to 4. 6. The distance between the radiation source and the image receptor; (“facteurs techniques”) “tube housing assembly” means an x-ray tube housing that has an x-ray tube installed in it; (“système radiogène”) “useful beam” means the delineated beam of x-rays that passes through the tube housing and the beamlimiting aperture; (“faisceau utile”) “whole-body-dose-equivalent” means the weighted average of the dose-equivalents received by all tissues in the body of an irradiated person; (“équivalent de dose pour le corps entire”) “work-load” means the degree of use of an x-ray machine expressed in milliampere minutes; (“charge de travail”) “x-ray exposure” means a quantity of x-rays delivered at a defined point in space or in a medium that is expressed in terms of the amount of electric charge produced by the radiation in a small mass of air located at the point; (“exposition aux rayons X”) “x-ray field” means the area of the intersection of a useful beam and one of the set of planes parallel to the plane of the image receptor; (“champ de rayons X”) “x-ray room” means a defined area where one or more permanently fixed x-ray machines and equipment are located; (“salle de radiologie”) “x-ray tube” means an evacuated envelope that is designed to produce x-rays by the bombardment of a metal target by accelerated electrons; (“tube à rayons X”) “x-ray worker” means a person who is qualified under the Act or the regulations to operate an x-ray machine. (“travailleur sous rayonnement”) R.R.O. 1990, Reg. 543, s. 1; O. Reg. 663/00, s. 1; O. Reg. 173/11, s. 1; O. Reg. 87/22, s. 1; O. Reg. 203/23, s. 1.