Mississippi Administrative Code › Title 15 - Mississippi Department of Health › Part 21 - Division of Radiological Health › Subpart 78 - Radiological Health › Chapter 1 - REGULATIONS FOR CONTROL OF RADIATION IN MISSISSIPPI › Subchapter 6 - X-Rays In The Healing Arts › Rule 15-21-78-1.6.2 - Definitions

Current through June 25, 2024
As used in this section, the following definitions
						apply:
1. "Accessible surface" means the external surface of the
						enclosure or housing provided by the manufacturer.
2. "Added filtration" means any filtration which is in
						addition to the inherent filtration.
3. "Aluminum equivalent" means the thickness of type 1100
						aluminum alloy29 affording the same attenuation,
						under specified conditions, as the material in question.
4. "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.
5. "Attenuation block" means a block or stack, having
						dimensions 20 centimeters by 20 centimeters by 3.8 centimeters, of type 1100
						aluminum alloy or other materials having equivalent attenuation.
6. "Automatic exposure control" 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 (See also
						"Phototimer").
7. "Barrier" (See "Protective barrier").
8. "Beam axis" means a line from the source through the
						centers of the x-ray fie 1ds.
9. "Beam-limiting device" means a device which provides a
						means to restrict the dimensions of the x-ray field.
10. "C-Arm x-ray system" means an x-ray system in which
						the image receptor and x-ray tube housing assembly are connected by a common
						mechanical support system in order to maintain a desired spatial relationship.
						This system is designed to allow a change in the projection of the beam through
						the patient without a change in the position of the patient.
11. "Cephalometric device" means a device intended for
						the radiographic visualization and measurement of the dimensions of the human
						head.
12. "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.
13. "Certified system" means any x-ray system comprised
						totally of certified components.
14. "Changeable filters" means any filter, exclusive of
						inherent filtration, which can be removed from the useful beam through any
						electronic, mechanical, or physical process.
15. "Coefficient of variation" or "C" means the ratio of
						the standard deviation to the mean value of a sample population of
						observations. It is estimated using the following equation:
Click Here To View
						Image
where
s = Estimated standard deviation of the
						population.
X
= Mean Value of observations in
						sample.
Xi =
						ith observation in sample.
n = Number of observations in sample.
16. "Computed tomography" means the production of a
						tomogram by the acquisition and computer processing of x-ray transmission
						data.
17. "Control panel" means that part of the x-ray control
						upon which are mounted the switches, knobs, pushbuttons, and other hardware
						necessary for setting the technique factors.
18. "Cooling curve" means the graphical relationship
						between heat units stored and cooling time.
19. "CT" (See "Computed tomography").
20. "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.
21. "Detector" (See "Radiation detector").
22. "Diagnostic source assembly" means the tube housing
						assembly with a beam-limiting device attached.
23. "Diagnostic x-ray imaging system" means an assemblage
						of components for the generation, emission and reception of x-rays and the
						transformation, storage and visual display of the resultant x-ray image.
24. "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.
25. "Direct scattered radiation" means that scattered
						radiation which has been deviated in direction only by materials irradiated by
						the useful beam (See "Scattered radiation").
26. "Entrance exposure rate" means the exposure free in
						air per unit time at the point where the center of the useful beam enters the
						patient.
27. "Equipment" (See "X-ray equipment").
28. "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."
29. "Filter" means material placed in the useful beam to
						absorb preferentially selected radiations.
30. "Fluoroscopic imaging assembly" means a subsystem in
						which x-ray photons produce a fluoroscopic image. 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.
31. "Focal spot" 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.
32. "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.
33. "Gonad shield" means a protective barrier for the
						testes or ovaries.
34. "Half-value layer" means the thickness of specified
						material which attenuates the beam of radiation to an extent such that the
exposure
rate is reduced to 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.
35. "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 to prescribe such
						x-ray tests for the purpose of diagnosis or treatment.
36. "HVL" (See "Half-value layer").
37. "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.
38. "Image receptor" means any device, such as a
						fluorescent screen or radiographic film, 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.
39. "Image receptor support" means, for mammographic
						systems, that part of the system designed to support the image receptor during
						mammography.
40. "Inherent filtration" means the filtration of the
						useful beam provided by the permanently installed components of the tube
						housing assembly.
41. "Irradiation" means the exposure of a living being or
						matter to ionizing radiation.
42. "Kilovolt (kV) [kilo electron volt (keV)]" means the
						energy equal to that acquired by a particle with one electron charge in passing
						through a potential difference of one thousand volts in a vacuum. [Note:
						current convention is to use kV for photons and keV for electrons].
43. "Kilovolts peak" (See "Peak tube potential").
44. "kVp" (See "Peak tube potential").
45. "kWs" means kilowatt second.
46. "Lead equivalent" means the thickness of the material
						in question affording the same attenuation, under specified conditions as
						lead.
47. "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.
48. "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 10 millicoulombs, i.e., 10 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 all other diagnostic source assemblies, the
						maximum-rated peak tube potential and the maximum-rated continuous tube current
						for the maximum-rated peak tube potential.
49. "Light field" means the area illuminated by light,
						being the locus of points at which the illumination exceeds a specific or
						specified level, simulating the radiation field.
50. "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-V1)/V1
where
Vn =
No-load line
						potential and
V1 =
Load line
						potential.
51. "mA" means milliampere.
52. "mAs" means milliampere second.
53. "Maximum line current" means the root-mean-square
						current in the supply line of an x-ray machine operating at its maximum
						rating.
54. "Mobile x-ray equipment" (See "X-ray
						equipment").
55. "Patient" means an individual or animal subjected to
						healing arts examination, diagnosis, or treatment.
56. "PBL" See "Positive beam limitation."
57. "Peak tube potential" means the maximum value of the
						potential difference across the x-ray tube during an exposure.
58. "Phantom" means a volume of material behaving in a
						manner similar to tissue with respect to the attenuation and scattering of
						radiation.
59. "Phototimer" means a method for controlling radiation
						exposures to image receptors by measuring 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").
60. "PID" (See "Position indicating device").
61. "Portable x-ray equipment" (See "X-ray
						equipment").
62. "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
						beam-limiting device.
63. "Positive beam limitation" means the automatic or
						semiautomatic adjustment of an x-ray beam to the selected image receptor size,
						whereby exposures cannot be made without such adjustment.
64. "Primary protective barrier" (See "Protective
						barrier").
65. "Protective apron" means an apron made of radiation
						absorbing materials used to reduce radiation exposure.
66. "Protective barrier" means a barrier of radiation
						absorbing material(s) used to reduce radiation exposure. The types of
						protective barriers are as follows:
a. "Primary protective barrier" means the material,
						excluding filters, placed in the useful beam, to protect anyone other than the
						patient from radiation exposure.
b. "Secondary protective barrier" means a barrier
						sufficient to attenuate the stray radiation to the required degree.
c. "Protective glove" means a glove made of radiation
						absorbing materials used to reduce radiation exposure.
67. "Qualified expert" means an individual who has
						demonstrated to the satisfaction of the Agency that such individual possesses
						the knowledge, training, and experience to measure ionizing radiation, to
						evaluate safety techniques, and to advise regarding radiation protection
						needs.
68. "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.
69. "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.
70. "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.
71. "Radiographic imaging system" means any system
						whereby a permanent or temporary image is recorded on an image receptor by the
						action of ionizing radiation.
72. "Rating" means the operating limits as specified by
						the component manufacturer.
73. "Recording" means producing a permanent form of an
						image resulting from x-ray photons.
74. "Scattered radiation" means radiation that, during
						passage through matter, has been deviated in direction (See "Direct scattered
						radiation").
75. "Secondary protective barrier" (See "Protective
						barrier").
76. "Shutter" means a device attached to the tube housing
						assembly which can totally intercept the entire cross section area of the
						useful beam and which has a lead equivalency not less than that of the tube
						housing assembly.
77. "SID" (See "Source-image receptor distance").
78. "Source" means the focal spot of the x-ray
						tube.
79. "Source-image receptor distance" means the distance
						from the source to the center of the input surface of the image
						receptor.
80. "Spot film" means a radiograph which is made during a
						fluoroscopic examination to permanently record conditions which exist during
						that fluoroscopic procedure.
81. "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 an image intensifier for the purpose of making a
						radiograph.
82. "SSD" means the distance between the source and the
						skin entrance plane of the patient.
83. " Stationary x-ray equipment" (See "X-ray
						equipment").
84. " Stray radiation" means the sum of leakage and
						scattered radiation.
85. "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 CT x-ray systems designed for pulsed operation,
						peak tube potential in kV, scan time in seconds, and either tube current in 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;
d. for CT x-ray systems 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
e. 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.
86. "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.
87. "Tomogram" means the depiction of the x-ray
						attenuation properties of a section through a body.
88. "Tube" means an x-ray tube, unless otherwise
						specified.
89. "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.
90. "Tube rating chart" means the set of curves which
						specify the rated limits of operation of the tube in terms of the technique
						factors.
91. "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.
92. "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.
93. "Visible area" means that portion of the input
						surface of the image receptor over which incident x-ray photons are producing a
						visible image.
94. "X-ray exposure control" means a device, switch,
						button, or other similar means by which an operator initiates and/or terminates
						the radiation exposure.
95. "X-ray equipment" means an x-ray system, subsystem,
						or component thereof Types of x-ray equipment are as follows:
a. "Mobile x-ray equipment" means x-ray equipment mounted
						on a permanent base with wheels and/or casters for moving while completely
						assembled.
b. "Portable x-ray equipment" means x-ray equipment
						designed to be hand carried.
c. "Stationary x-ray equipment" means x-ray equipment
						which is installed in a fixed location.
96. "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 exposure rate is one-fourth of the maximum in the intersection.
97. "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.
98. "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.
99. "X-ray subsystem" means any combination of two or
						more components of an x-ray system.
100. "X-ray tube" means any electron tube which is
						designed to be used primarily for the production of x-rays.
29 The nominal chemical
						composition of type 1100 aluminum alloy is 99.00 percent minimum aluminum, 0.12
						percent copper.
Miss. Code Ann.
						§
												45-14-11