DHS 157.03(50)(e)(e) Any discrete source of naturally occurring radioactive material, other than source material, that the NRC, in consultation with the Administrator of the Environmental Protection Agency, the Secretary of Energy, the Secretary of Homeland Security, and the head of any other appropriate federal agency, determines would pose a threat similar to the threat posed by a discrete source of radium-226 to the public health and safety or the common defense and security, and is extracted or converted after extraction for use in a commercial, medical or research activity. DHS 157.03(51)(51) “Cabinet radiography” means industrial radiography conducted in an enclosure or cabinet so shielded that every location on the exterior meets the dose limits for individual members of the public as specified in s. DHS 157.23 (1). DHS 157.03(52)(52) “Cabinet x-ray system” means an x-ray system, manufactured under the requirements of 21 CFR 1020.40, with an x-ray tube installed in an enclosure that is independent of existing architectural structures except the floor. The cabinet x-ray system is intended to contain at least that portion of a material being irradiated, provide radiation attenuation and exclude personnel from its interior during generation of radiation. “Cabinet x-ray system” includes x-ray systems designed primarily for the inspection of carry-on baggage at airline, railroad and bus terminals and in similar facilities. An x-ray tube used within a shielded part of a building or x-ray equipment that may temporarily or occasionally incorporate portable shielding is not considered a cabinet x-ray system. DHS 157.03(53)(53) “Calendar quarter” means a period of time equal to one-fourth of the year observed by the licensee or registrant, providing that the beginning of the first quarter in a year coincides with the starting date of the year and that no day is omitted or duplicated in consecutive quarters. DHS 157.03 NoteNote: A calendar quarter is approximately 13 consecutive weeks.
DHS 157.03(54)(54) “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 to maintain a desired spatial relationship. The system allows the operator to change the projection of the beam through the patient without changing the position of the patient. DHS 157.03(55)(55) “Calibration” means determining either of the following: DHS 157.03(55)(a)(a) The response or reading of an instrument relative to a series of known radiation values over the range of the instrument. DHS 157.03(56)(56) “Carrier” means a person engaged in the transportation of passengers or property by land or water as a common, contract or private carrier or by civil aircraft. DHS 157.03(56g)(56g) “Category 1 quantity of radioactive material” means a quantity of radioactive material meeting or exceeding the category 1 threshold in ch. DHS 157 Appendix U. DHS 157.03 NoteNote: This is determined by calculating the ratio of the total activity of each radionuclide to the category 1 threshold for that radionuclide and adding the ratios together. If the sum is equal to or exceeds 1, the quantity would be considered a category 1 quantity. Category 1 quantities of radioactive material do not include the radioactive material contained in any fuel assembly, subassembly, fuel rod, or fuel pellet. Chapter DHS 157 Appendix U is used to determine the category 1 threshold for a category 1 quantity of radioactive material. The category 1 and category 2 thresholds in ch. DHS 157 Appendix U and ch. DHS 157 Appendix T are not interchangeable. DHS 157.03(56r)(56r) “Category 2 quantity of radioactive material” means a quantity of radioactive material meeting or exceeding the category 2 threshold, but less than the category 1 threshold in ch. DHS 157 Appendix U. DHS 157.03 NoteNote: This is determined by calculating the ratio of the total activity of each radionuclide to the category 2 threshold for that radionuclide and adding the ratios together. If the sum is equal to or exceeds 1, the quantity would be considered a category 2 quantity. Category 2 quantities of radioactive material do not include the radioactive material contained in any fuel assembly, subassembly, fuel rod, or fuel pellet. Chapter DHS 157 Appendix U is used to determine the category 2 threshold for a category 2 quantity of radioactive material. The category 1 and category 2 thresholds in ch. DHS 157 Appendix U and ch. DHS 157 Appendix T are not interchangeable. DHS 157.03(57)(57) “Cephalometric device” means a device intended for the radiographic visualization and measurement of the dimensions of the human head. DHS 157.03(57c)(57c) “Certifiable cabinet x-ray system” means an existing uncertified radiation generating device that has been modified to meet the certification requirements specified in 21 CFR 1020.40. DHS 157.03(57g)(57g) “Certificate holder” means a person who has been issued a certificate of compliance or other package approval by the U.S. nuclear regulatory commission. DHS 157.03(57r)(57r) “Certificate of Compliance” or “CoC” means the certificate issued by the U.S. nuclear regulatory commission under subpart D of 10 CFR 71 which approves the design of a package for the transportation of radioactive material. DHS 157.03(57w)(57w) “Certified cabinet x-ray system” means a radiation generating device certified by the manufacturer in accordance with 21 CFR 1010.2 as being manufactured and assembled pursuant to the provisions of applicable federal radiation safety performance standards 21 CFR 1010 and 1020.40. DHS 157.03(60)(60) “Certifying entity” means an independent certifying organization meeting the requirements in 10 CFR 34, Appendix A or an agreement state meeting the requirements in 10 CFR 34, Appendix A, Parts II and III. DHS 157.03(61)(61) “Changeable filters” means any filter, exclusive of inherent filtration, that may be removed from the useful beam through any electronic, mechanical or physical process. DHS 157.03(62)(62) “Chelating agent” means a chemical compound used to remove radioactive material from other substances. DHS 157.03 NoteNote: Examples of chelating agents are amine polycarboxylic acids, hydroxycarboxylic acids, glucinic acid and polycarboxylic acids.
DHS 157.03(63)(63) “Chiropractor” means an individual licensed under ch. 446, Stats., to practice chiropractic. DHS 157.03(64)(64) “Class” means a classification scheme for inhaled material according to the material’s rate of clearance from the pulmonary region of the lung. Materials are classified as D, W or Y, depending on the amount of time half of the material clears from human lungs. Half of class D material clears from lungs in less than 10 days; half of class W material clears from lungs in from 10 to 100 days; and half of class Y material clears from lungs in greater than 100 days. DHS 157.03(65)(65) “Cinefluorography” means the continuous recording of a fluoroscopy image using movie film. DHS 157.03(66)(66) “Client’s address” means the area of use or a temporary jobsite for the purpose of providing mobile medical service. DHS 157.03(66m)(66m) “Closed-beam x-ray equipment” means a system in which the beam path cannot be entered by any part of the body during normal operation. DHS 157.03(67)(67) “Closed transport vehicle” means a transport vehicle equipped with a securely attached exterior enclosure that during normal transportation restricts the access of unauthorized persons to the cargo space containing a radioactive material. The enclosure may be either temporary or permanent but shall limit access from top, sides and ends. In the case of packaged materials, the vehicle may be of the “see-through” type that allows observation of the packages while prohibiting access. DHS 157.03(68)(68) “Coefficient of variation” 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 = standard deviation of the observed values;
X = mean value of observations in sample;
Xi = ith observation in sample; and
n = number of observations in sample.
DHS 157.03(69)(69) “Collective dose” means the sum of the individual doses received in a given period of time by a specified population from exposure to a specified source of radiation. DHS 157.03(70)(a)(a) A radiation shield that is placed on the end of the guide tube or directly onto a radiographic exposure device to restrict the size of the radiation beam when the sealed source is moved into position to make a radiographic exposure. DHS 157.03(70)(b)(b) A device attached to an x-ray tube that limits the radiation area. DHS 157.03(71)(71) “Commission” means the United States nuclear regulatory commission. DHS 157.03(72)(72) “Committed dose equivalent” or “CDE” means the dose equivalent to organs or tissues of reference that will be received from an intake of radioactive material by an individual during the 50-year period following the intake. DHS 157.03(73)(73) “Committed effective dose equivalent” or “CEDE” is the sum of the products of the weighting factors applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to each of these organs or tissues. DHS 157.03 NoteNote: Committed effective dose equivalent (HE,50) equals the sum of the weighting factor (wT,) times the committed dose equivalent (HT,50).
DHS 157.03(74)(74) “Computed tomography” or “CT” means the production of a tomogram by the acquisition and computer processing of x-ray transmission data. DHS 157.03(75)(a)(a) “Computed tomography dose index” or “CTDI” means the integral from -10T to +10T of the dose profile along a line perpendicular to the tomographic plane divided by the product of the nominal tomographic section thickness and the number of tomograms produced in a single scan, that is: where:
z = position along a line perpendicular to the tomographic plane;
D(z) = dose at position z;
T = nominal tomographic section thickness in millimeters;
n = number of tomograms produced in a single scan.
DHS 157.03(75)(b)(b) The definition of “computed tomography dose index” assumes that the dose profile is centered around z=0 and that, for a multiple tomogram system, the scan increment between adjacent scans is nT. DHS 157.03(75m)(75m) “Consignment” means each shipment of a package or groups of packages or load of radioactive material offered by a shipper for transport. DHS 157.03(75r)(75r) “Consortium” means an association of medical use licensees and a PET facility in the same geographical area, physically located at an educational institution, a federal facility or a medical facility, that jointly own or share in the operation and maintenance cost of the PET facility that produces PET radionuclides for use in producing radioactive drugs within the consortium for noncommercial distributions among its associated members for medical use. DHS 157.03(76)(76) “Constraint” means a value above which specified licensee or registrant actions are required. DHS 157.03(77)(77) “Contact therapy system” means a therapeutic radiation machine with a short target to skin distance, usually less than 5 centimeters. DHS 157.03(77m)(77m) “Contamination” means the presence of a radioactive substance on a surface in quantities in excess of 0.4 Bq/cm2 (1x10-5 microcurie/cm2) for beta and gamma emitters and low toxicity alpha emitters, or 0.04 Bq/cm2 (1x10-6 microcurie/cm2) for all other alpha emitters. DHS 157.03(78)(78) “Control cable” means the cable that is connected to the source assembly and used to drive the source to and from the exposure location. DHS 157.03(79)(79) “Control drive mechanism” means a device that enables the source assembly to be moved into and out of the exposure device. DHS 157.03(80)(80) “Control panel” means that part of an x-ray control upon which are mounted the switches, knobs, pushbuttons and other hardware necessary for manually setting the technique factors. DHS 157.03(81)(81) “Control tube” means a protective sheath for guiding the control cable. The control tube connects the control drive mechanism to the radiographic exposure device. DHS 157.03(82)(82) “Controlled area” means an area, outside of a restricted area but inside the site boundary, access to which may be limited by the licensee or registrant for any reason. DHS 157.03(82m)(a)(a) For transport by public highway or rail, any transport vehicle or large freight container. DHS 157.03(82m)(b)(b) For transport by water, any vessel, or any hold, compartment or defined deck area of a vessel, including any transport vehicle on board the vessel. DHS 157.03(83)(83) “Cooling curve” means the graphical relationship between heat units stored and cooling time. DHS 157.03(84)(84) “Critical group” means the group of individuals reasonably expected to receive the greatest exposure to residual radioactivity for any applicable set of circumstances. DHS 157.03(84m)(84m) ”Criticality safety index” or ”CSI” means the dimensionless number, rounded up to the next tenth, assigned to and placed on the label of a fissile material package to designate the degree of control of accumulation of packages, overpacks, or freight containers containing fissile material during transportation. DHS 157.03 NoteNote: Determination of the criticality safety index is described in s. DHS 157.93 (7) and (8) and 10 CFR 71.59. The CSI for an overpack, freight container, consignment or conveyance containing fissile material packages is the arithmetic sum of the criticality safety indices of all the fissile material packages contained within the overpack freight container, consignment, or conveyance. DHS 157.03(85)(85) “CT conditions of operation” means all selectable parameters governing the operation of a CT x-ray system including nominal tomographic section thickness, filtration and the technique factors as defined in s. DHS 157.84. DHS 157.03(86)(86) “CT gantry” means the tube housing assemblies, beam-limiting devices, detectors and the supporting structures and frames that hold these components. DHS 157.03(87)(87) “CT number” or “CTN” means the number used to represent the x-ray attenuation associated with each elemental area of the CT image as expressed in the following equation: where:
K = a constant, a normal value of 1,000 when the Houndsfield scale of CTN is used;
= linear attenuation coefficient of the material of interest; = linear attenuation coefficient of water. DHS 157.03(87m)(87m) “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. DHS 157.03(88)(88) “Curie” or “Ci” means 3.7 x 1010 disintegrations per second = 3.7 x 1010 becquerels = 2.22 x 1012 disintegrations per minute. DHS 157.03(89)(89) “Dead-man switch” means a switch so constructed that a circuit closing contact may be maintained only by continuous pressure on the switch by the operator. DHS 157.03(90)(90) “Declared pregnant woman” means a woman who has voluntarily informed the licensee or registrant, in writing, of her pregnancy and the estimated date of conception. The declaration remains in effect until the declared pregnant woman withdraws the declaration in writing or is no longer pregnant. DHS 157.03(91)(91) “Decommission” means to remove a facility or site safely from service and reduce residual radioactivity to a level that permits release of the property for unrestricted use and termination of the license; or release of the property under restricted conditions and termination of the license. DHS 157.03(92)(92) “Dedicated check source” means a radioactive source that is used to assure the constant operation of a radiation detection or measurement device over several months or years. DHS 157.03(93)(93) “Deep dose equivalent” or “Hd” means the dose equivalent at a tissue depth of one centimeter (1000 mg/cm2) and applies to external whole body exposure.
