Code of Massachusetts Regulations
105 CMR - DEPARTMENT OF PUBLIC HEALTH
Title 105 CMR 120.000 - The Control of Radiation
RECORDKEEPING REQUIREMENTS
Section 120.402 - Definitions
As used in 105 CMR 120.400, the following definitions apply:
Accessible Surface means the external surface of the enclosure or housing provided by the manufacturer.
Accessory Component means:
(1) A component used with diagnostic X-ray systems, such as a cradle or film changer, that is not necessary for the compliance of the system with applicable provisions of 105 CMR 120.400 but which requires an initial determination of compatibility with the system; or
(2) A component necessary for compliance of the system with applicable provisions of 105 CMR 120.400 but which may be interchanged with similar compatible components without affecting the system's compliance, such as one of a set of interchangeable beam-limiting devices; or
(3) A component compatible with all X-ray systems with which it may be used and that does not require compatibility or installation instructions, such as a tabletop cassette holder.
Added Filtration means any filtration which is in addition to the inherent filtration.
Air Kerma means kerma in air (see definition of Kerma)
Air Kerma Rate (AKR) means the air kerma per unit time.
Aluminum Equivalent means the thickness of type 1100 aluminum alloy1 affording the same attenuation, under specified conditions, as the material in question.
Approved Provider means a post-secondary institution of higher learning, a provider approved by the American Society of Radiologic Technologists (ASRT), a provider of Category I CME approved by the American Academy of Physician Assistants (AAPA), a provider accredited by the Accreditation Council for Continuing Medical Education (ACCME) or ACCME-recognized state medical society (SMS), a provider of Category 1 CME approved by the American Medical Association (AMA), or other recognized national continuing medical education approval body approved by the Agency.
Assembler means any person 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 who assembles components into an x-ray system that is subsequently used to provide professional or commercial services.
Attenuation Block means a block or stack, having dimensions 20 centimeters by 20 centimeters by 3.8 centimeters, of type 1100 aluminum alloy1 or other materials having equivalent attenuation.
Automatic Exposure Control (AEC) means a device which automatically controls one or more technique factors in order to obtain at a preselected location(s) a required quantity of radiation (Includes devices such as phototimers and ion chambers).
Automatic Exposure Rate Control (AERC) means a device which automatically controls one or more technique factors in order to obtain, at a preselected location(s), a required quantity of radiation per unit time.
Barrier (See 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.
Bone Densitometry System means a medical device which uses electronically-produced ionizing radiation to determine the density of bone structures of human patients.
C-arm Fluoroscope means a fluoroscopic x-ray system in which the image receptor and x-ray tube housing assembly are connected or coordinated. 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 an x-ray film [imaging] cassette during an x-ray exposure.
Cephalometric Device means a device intended for the radiographic visualization and measurement of the dimensions of the human head.
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 any x-ray system which has one or more certified component(s).
Changeable Filters means any filter, exclusive of inherent filtration, which can be removed from the useful beam through any electronic, mechanical, or physical process.
Coefficient of Variation or C means the ratio of the standard deviation to the mean value of a population of observations. It is estimated using the following equation:
where
s = Estimated standard deviation of the population.
X = Mean value of observations in sample.
X = ith observation in sample.
n = Number of observations in sample.
Computed Tomography means the production of a tomogram by the acquisition and computer processing of x-ray transmission data.
Contact Therapy System means an x-ray system used for therapy with the x-ray tube port placed in contact with or within five centimeters of the surface being treated.
Control Panel means that part of the x-ray control upon which are mounted the switches, knobs, pushbuttons, and other hardware necessary for manually setting the technique factors.
Contrast Scale (CS) means the change in the linear attenuation coefficient per CTN relative to water; that is:
where:
µx = linear attenuation coefficient of the material of interest
µw = linear attenuation coefficient of water
(CTN)x = CTN of the material of interest
(CTN)w = CTN of water
Cooling Curve means the graphical relationship between heat units stored and cooling time.
CR means: Computed Radiography, an indirect type of imaging system. The receptor used within a CR cassette is called a photostimulable imaging plate and it absorbs the radiation exiting the patient. The exposed plate is processed in a CR reader, where the absorbed energy is extracted. The resultant latent image data is converted from an analog to a digital signal and a digital image is created.
Cradle means:
(1) A removable device which supports and may restrain a patient above an x-ray table; or
(2) A device;
(a) Whose patient support structure is interposed between the patient and the image receptor during normal use;
(b) Which is equipped with means for patient restraint; and
(c) Which is capable of rotation about its long (longitudinal) axis.
CT means computed tomography; the production of a tomogram by the acquisition and computer processing of x-ray transmission data.
CT Condition 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 105 CMR 120.400.
CT Gantry means the tube housing assemblies, beam-limiting devices, detectors, and the supporting structures and frames which hold these components.
CT Number (CTN) means the number used to represent the x-ray attenuation associated with each elemental area of the CT image, that is:
where:
k = contrast (a value of 1,000 is assigned when the Hounsefield scale of CTN is used)
µx = linear attenuation coefficient of the material of interest
µw = linear attenuation of water w
Cumulative Air Kerma means the total air kerma accrued from the beginning of an examination or procedure and includes all contributions from fluoroscopic and radiographic irradiation.
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.
Diagnostic X-ray Imaging System means an assemblage of components for the generation, emission, and reception of x-ray and the transformation, storage, and visual display of the resultant x-ray image.
Direct Scattered Radiation means that scattered radiation which has been deviated in direction only by materials irradiated by the useful beam (See Scattered Radiation).
Dose means the absorbed dose as defined by the International Commission on Radiation Units and Measurements. The absorbed dose, D, is the quotient of de by dm, where de is the mean energy imparted to matter of mass dm; thus D=de/dm, in units of J/kg, where the special name of the unit of absorbed dose is gray (Gy).
DR means Direct Radiography or Digital Radiography, is a form of x-ray imaging where digital x-ray sensors are used instead of traditional photographic film.
Elemental Area means the smallest area within a tomogram for which the x-ray attenuation properties of a body are depicted.
Entrance Exposure Rate means the Exposure per unit time at the point where the center of the useful beam enters the patient.
Equipment (See X-ray Equipment).
Exposure (X) means the quotient of dQ by dm where dQ is the absolute value of the total charge of the ions of one sign produced in air when all the electrons and positrons liberated or created by photons in air of mass dm are completely stopped in air; thus X=dQ/dm, in units of C/kg. A second meaning of exposure is the process or condition during which the x-ray tube produces x-ray radiation.
Facility means the location within one building or vehicle and under the same administrative control at which one or more x-ray equipment systems are installed or located for the purpose of diagnosis or treatment.
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 Air Kerma Display Devices means separate devices, subsystems, or components that provide the display of AKR and cumulative air kerma, respectively. They include radiation detectors, if any, electronic and computer components, associated software, and data displays.
Fluoroscopic Imaging Assembly means a subsystem in which x-ray photons produce a fluoroscopic images or radiographic images recorded from the fluoroscopic image receptor. It includes the image receptor(s) such as the image intensifier and spot-film device, 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.
Fluoroscopic Procedure means the production and display of serial x-ray images for the purpose of observing real-time motion of anatomical structures.
Fluoroscopy means a technique for generating x-ray images and presenting them simultaneously and continuously as visible images. This term has the same meaning as the term "radioscopy" in the standards of the International Electrotechnical Commission.
Focal Spot (Actual) means the area projected on the anode of the x-ray tube 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.
Gonad Shield means a protective barrier for the testes or ovaries.
Half-value Layer means the thickness of specified material which attenuate the beam of radiation to an extent such that the exposure rate is reduced to one-half of its original value. In 105 CMR 120.402: Half-value Layer, 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 x-ray equipment that is designed to be hand-held during operation.
Healing Arts Screening means the testing of human beings using x-ray machines for the detection or evaluation of health indications when such tests are not specifically and individually ordered by a licensed practitioner of the healing arts legally authorized by the Commonwealth of Massachusetts to prescribe such x-ray tests for the purpose of diagnosis or treatment. to prescribe such x-ray tests 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, i.e., kVp x mA x second.
HVL (See Half-value Layer).
Image Intensifier means a device, installed in its housing, which instantaneously converts an x-ray pattern into a corresponding light image of higher energy density.
Image Receptor means any device, such as a fluorescent screen, radiographic film, x-ray image intensifier tube, solid-state detector, or gaseous detector which transforms incident x-ray photons either into a visible image or into another form which 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.
Inherent Filtration means the filtration of the useful beam provided by the permanently installed components of the tube housing assembly.
Interventional Procedures means procedures that utilize imaging for guidance. Imaging includes, but is not limited to, fluoroscopy and CT.
Irradiation means the exposure of matter to ionizing radiation.
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 means the quantity defined by the International Commission on Radiation Units and Measurements. The kerma, K, is the quotient of dEtr by dm, where dEtr is the sum of the initial kinetic energies of all the charged participles liberated by uncharged particles in a mass dm of material; thus K=dEtr/dm, in units of J/kg, where the special name for the unit of kerma is gray (Gy). When the material is air, the quantity is referred to as "air kerma."
Kilovolts Peak (See Peak Tube Potential).
kV means kilovolts.
kVp (See Peak Tube Potential).
kWs means kilowatt second.
Last Image Hold (LIH) radiograph means an image obtained either by retaining one or more fluoroscopic images, which maybe temporarily integrated, at the end of a fluoroscopic exposure or by initiating a separate and distinct radiographic exposure automatically and immediately in conjunction with termination of the fluoroscopic exposure.
Lateral Fluoroscope means the x-ray tube and image receptor combination in a biplane system dedicated to the lateral projection. It consists of the lateral x-ray tube housing assembly and the lateral image receptor that are fixed in position relative to the table with the x-ray beam axis parallel to the plane of the table.
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 or therapeutic source assembly except for:
(1) The useful beam; and,
(2) Radiation produced when the exposure switch or timer is not activated.
Leakage Technique Factors means the technique factors associated with the diagnostic or therapeutic source assembly which are used in measuring leakage radiation. They are defined as follows:
(1) 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, i.e., ten milliampere seconds, or the minimum obtainable from the unit, whichever is larger.
(2) 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.
(3) For all other diagnostic or therapeutic source assemblies, the maximum-rated peak tube potential and the maximum-rated continuous tube current for the maximum-rated peak tube potential.
Linear Attenuation Coefficient (µ) means the quotient of dN/N by d1 when dN/N is the fraction of uncharged ionizing radiation that experience interactions in traveling a distance d1 in a specific material.
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.
Line-voltage Regulation means the difference between the no- load and the load line potentials expressed as a percent of the load line potential. It is calculated using the following equation:
Percent line-voltage regulation = 100 (Vn-Vl)/Vl
where
Vn = No-load line potential and
Vl = Load line potential.
mA means milliampere.
mAs means milliampere second.
Maximum Line Current means the root-mean-square current in the supply line of an x-ray machine operating at its maximum rating.
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. The set of distinct technique factors and control settings for the mode may be selected by the operation of a single control. Examples of distinct modes of operation include normal fluoroscopy (analog or digital), high-level control fluoroscopy, cineradiography (analog and digital), digital subtraction angiography, electronic radiography using the fluoroscopic image receptor, and photospot recording. In a specific mode of operation, certain system variables affecting kerma, AKR, or image quality, such as image magnification, x-ray field size, pulse rate, pulse duration, number of pulses, source-image receptor distance (SID), or optical aperture, may be adjustable or may vary; their variation per se does not comprise a mode of operation different from the one that has been selected.
Movable Tabletop means a tabletop which, when assembled for use, is capable of movement with respect to its supporting structure within the plane of the tabletop.
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.
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 x-ray transmission data are collected.
Nurse Practitioner means a person licensed as a Registered Nurse by the Massachusetts Board in Nursing pursuant to M.G.L. c. 112, § 74, who is authorized by such Board to practice in an advanced practice nursing role as a nurse practitioner pursuant to M.G.L. c. 112, § 80B, and 244 CMR 4.00: The Practice of Nursing in the Expanded Role.
NVLAP means National Voluntary Laboratory Accreditation Program.
Patient means an individual subjected to healing arts examination, diagnosis, or treatment.
PBL See105 CMR 120.402: 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. This requires that both the atomic number (Z) and the density of the material be similar to that of tissue.
Phototimer means a method for controlling radiation exposures to image receptors by the amount of radiation which reaches a radiation monitoring device(s). The radiation monitoring device(s) is part of an electronic circuit which controls the duration of time the tube is activated (See Automatic Exposure Control).
Physician Assistant means a person licensed as a physician assistant by the Massachusetts Board of Registration in Physician Assistants pursuant to M.G.L. c. 112, § 9I.
PID (See "Position indicating device").
Portable X-ray Equipment (See X-ray Equipment).
Position Indicating Device means a device on dental x-ray equipment used to indicate the beam position and to establish a definite source-surface (skin) distance. It may or may not incorporate or serve as a bean-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.
Post-secondary Institution of Higher Education means a degree granting institution duly accredited by an accrediting agency recognized by the United States Department of Education.
Practitioner of the Healing Arts means an individual licensed to practice healing arts by the Commonwealth of Massachusetts.
Primary Protective Barrier (See 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(s) used to reduce radiation exposure. The types of protective barriers are as follows:
(1) "Primary protective barrier" means the material, excluding filters, placed in the useful beam;
(2) "Secondary protective barrier" means a barrier sufficient to attenuate the stray radiation.
Protective Glove means a glove made of radiation absorbing materials used to reduce radiation exposure.
Pulsed Mode means operation of the 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 1/2 second.
Qualified Medical Physicist means an individual is:
(1) Registered with the Agency, under the provisions of 105 CMR 120.026, as a provider of radiation services in the area of calibration and compliance surveys and,
(2) Is certified by the American Board of Radiology in:
(a) Therapeutic medical physics; or
(b) Diagnostic medical physics; or
(c) Nuclear medical physics; or
(3) Is certified by the American Board of Medical Physics; or
(4) Is certified by the Canadian College of Medical Physics; or
(5) Hold a master's or doctor's degree in physics, biophysics, radiological physics, Radiological Science, Nuclear Physics, health physics, or other catagory approved by the Agency.
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 Therapy Simulation System means a radiographic or fluoroscopic x-ray 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 receptor on which the image is created directly or indirectly by an x-ray pattern and results in a permanent record.
Radiography means a technique for generating and recording an x-ray pattern for the purpose of providing the user with an image(s) after termination of the exposure.
Radiographic Imaging System means any system whereby a permanent or semi-permanent image is recorded on an image receptor by the action of ionizing radiation.
Rated Line Voltage means the range of potentials, in volts, of the supply line specified by the manufacturer at which the x-ray machine is designed to operate.
Rated Output Current means the maximum allowable load current of the x-ray high-voltage generator.
Rating means the operating limits as specified by the component manufacturer.
Recording means producing a retrievable form of an image resulting from x-ray photons.
Reference Plane means a plane which is displaced from and parallel to the tomographic plane.
Routine means diagnostic procedures utilizing x-ray equipment that are performed at least weekly.
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 tomogram.
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 preselected set of two or more scans performed consecutively under preselected CT conditions of operation.
Scan Time means the period of time between the beginning and end of x-ray transmission data accumulation for a single scan.
Scattered Radiation means radiation that, during passage through matter, has been deviated in direction (See Direct Scattered Radiation ).
Secondary Dose Monitoring System means a system which will terminate irradiation in the event of failure of the primary system.
Secondary Protective Barrier (See Protective Barrier).
Shutter means a device attached to the tube housing assembly which can totally intercept the useful beam and which 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.
Solid State X-ray Imaging Device means an assembly, typically in a rectangular panel configuration, that intercepts x-ray photons and converts the photon energy into a modulated electronic signal representative of the x-ray intensity over the area of the imaging device. The electronic signal is then used to create an image for display and/or storage.
Source means the focal spot of the x-ray tube.
Source-image Receptor Distance 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 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 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.
SSD means the distance from the source to the center of the entrant x-ray field in the plan tangent to the patient skin surface.
Stationary Tabletop means a tabletop which, when assembled for use, is incapable of movement with respect to its supporting structure within the plane of the tabletop.
Stationary X-ray Equipment (See X-ray Equipment).
Stray Radiation means the sum of leakage and scattered radiation.
Supervising Physician means a physician who holds a full license issued by the Board of Registration in Medicine and who supervises all professional activities of a physician assistant in accordance with 243 CMR 2.08 and 263 CMR 5.00. For the purposes of 105 CMR 120.405, a supervising physician shall meet the requirements of 120.405(K)(1)(a) or (b).
Technique Factors means the conditions of operation. They are specified as follows:
(1) For capacitor energy storage equipment, peak tube potential in kV and quantity of charge in mAs;
(2) For field emission equipment rated for pulsed operation, peak tube potential in kV and number of x-ray pulses;
(3) For CT equipment designed for pulsed operations, peaktube potential in kV, scan time in seconds, and either tube current in milliamperes (mA), x-ray pulse width in seconds, and the number of x-ray pulses per scan or the product of tube current, x-ray pulse width, and the number of x-ray pulses in mAs;
(4) For CT equipment not designed for pulsed operation, peak tube potential in kV, and either tube current in mA and scan time in seconds or the product of tube current and exposure time in mAs and the scan time when the scan time and exposure time are equivalent; and,
(5) For all other equipment, peak tube potential in kV and either tube current in mA and exposure time in seconds, or 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 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 and/or filament transformers and other appropriate elements when such 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 exposure controls are in a mode to cause the system to produce radiation.
Variable-aperture Beam-limiting Device means a beam-limiting device which has capacity for stepless adjustment of the x-ray field size at a given SID.
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 and/or terminates the radiation exposure. The x-ray exposure control may include such associated equipment as timers and back-up timers.
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, phototimer, automatic brightness stabilizers, and similar devices, which control the technique factors of an x-ray exposure.
X-ray Equipment means an x-ray system, subsystem, or component thereof. Types of x-ray equipment are as follows:
(1) "Mobile X-ray Equipment" means x-ray equipment mounted on a permanent base with wheels and/or casters for moving while completely assembled.
(2) "Portable X-ray Equipment" means x-ray equipment designed to be hand-carried.
(3) "Stationary X-ray Equipment" 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 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 AKR is 1/4 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(s), 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 Table means a patient support device with its patient support structure (tabletop) interposed between the patient and the image receptor 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 buckey), cassette tunnel, image intensifier, or spot-film device beneath the tabletop.
X-ray Tube means any electron tube which is designed to be used primarily for the production of x-rays.
1 The nominal chemical composition of type 1100 aluminum alloy is 99.00% minimum aluminum, 0.12% copper.
