Chapter DHS 157

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) (82m) “Conveyance" means any one of the following:

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(82m)(c) (c) For transport by aircraft, any aircraft.

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 Note Note: 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:

- See PDF for diagram

where:

K = a constant, a normal value of 1,000 when the Houndsfield scale of CTN is used;

- See PDF for diagram = linear attenuation coefficient of the material of interest;

- See PDF for diagram = 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.

DHS 157.03(94) (94) “Deliberate misconduct" means an intentional act or omission that the person knows would cause any of the following:

DHS 157.03(94)(a) (a) A licensee, registrant or applicant to be in violation of any requirement under this chapter, any order of the department, or any term, condition or limitation of any license or registration issued by the department under this chapter.

DHS 157.03(94)(b) (b) A violation of a requirement, procedure, instruction, contract, purchase order or policy of a licensee, registrant, applicant, or contractor or subcontractor of a licensee, registrant or applicant.

DHS 157.03(95) (95) “Demand respirator" means an atmosphere-supplying respirator that admits breathing air to the face piece only when a negative pressure is created inside the facepiece by inhalation.

DHS 157.03(96) (96) “Dentist" means an individual licensed under ch. 447, Stats., to practice dentistry.

DHS 157.03(97) (97) “Department" means the department of health services.

DHS 157.03(98) (98) “Depleted uranium" means uranium containing less uranium-235 than the naturally occurring distribution of uranium isotopes.

DHS 157.03(99) (99) “Derived air concentration" or “DAC" means the concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours under conditions of light work, results in an intake of one ALI.

DHS 157.03 Note Note: For purposes of this chapter, the condition of light work is an inhalation rate of 1.2 cubic meters of air per hour for 2,000 hours in a year. DAC values are given in Table I, column 3, of ch. DHS 157 Appendix E.

DHS 157.03(100) (100) “Derived air concentration-hour" or “DAC-hour" means the product of the concentration of radioactive material in air, expressed as a fraction or multiple of the derived air concentration for each radionuclide, and the time of exposure to that radionuclide, in hours. A licensee or registrant may take 2,000 DAC-hours to represent one ALI, equivalent to a committed effective dose equivalent of 0.05 Sv (5 rem).

DHS 157.03(101) (101) “Detector" means a device which in the presence of radiation provides, by either direct or indirect means, a signal or other indication suitable for use in measuring one or more quantities of incident radiation.

DHS 157.03(101m) (101m) “Deuterium" means deuterium and any deuterium compounds, including heavy water, in which the ratio of deuterium atoms to hydrogen atoms exceeds 1:5000.

DHS 157.03(102) (102) “Diagnostic source assembly" means the tube housing assembly with a beam-limiting device attached.

DHS 157.03(103) (103) “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.

DHS 157.03(103m) (103m) “DICOM" means digital imaging and communications in medicine.

DHS 157.03(103r) (103r) “Discrete source" means a radionuclide that has been processed so that its concentration within a material has been purposely increased for use for commercial, medical, or research activities.

DHS 157.03(104) (104) “Disposable respirator" means a respirator for which maintenance is not intended and that is designed to be discarded after excessive breathing resistance, sorbent exhaustion, physical damage, or end-of-service-life renders it unsuitable for use. Examples of this type of respirator are a disposable half-mask respirator or a disposable escape-only self-contained breathing apparatus.

DHS 157.03 Note Note: Sorbent exhaustion refers to the inability of an absorbent material to absorb any more of the material for which it was designed.

DHS 157.03(105) (105) “Disposal" means the isolation of radioactive wastes from the environment inhabited by man and containing his food-chains by emplacement in a land disposal facility.

DHS 157.03(106) (106) “Disposal site" means that portion of a land disposal facility which is used for the disposal of waste. It consists of disposal units and a buffer zone.

DHS 157.03(107) (107) “Disposal unit" means a discrete portion of a disposal site into which waste is placed for disposal.

DHS 157.03(108) (108) “Distinguishable from background" means that the detectable concentration of a radionuclide is statistically different from the background concentration of that radionuclide in the vicinity of that site or, in the case of structures, in similar materials using adequate measurement technology, survey and statistical techniques.

DHS 157.03(108m) (108m) “Diversion" means the unauthorized movement of category 1 or category 2 quantity of radioactive material that is subject to subch. XV to a location different from the material's authorized destination inside or outside of the site at which the material is used or stored.

DHS 157.03(109) (109) “Dose equivalent" or “H T" means the product of the absorbed dose in tissue, quality factor and all other necessary modifying factors at the location of interest. The units of dose equivalent are the sievert and rem.

DHS 157.03(109m) (109m) “Dose length product” or “DLP” means the metric which is related to the total energy imparted in the patient, and is determined by multiplying the CTDIvol value by the scan length, resulting in the units of mGy-cm. DLP is calculated using the following formula:

- See PDF for diagram

where:

L = the length of patient scanned.

p = is the pitch.

CTDI100,cent = CTDI100 value determined at the center of a standardized phantom.

CTDI100,periphery = CTDI100 value determined at the periphery of a standardized phantom.

DHS 157.03(110) (110) “Dose limits" means the permissible upper bounds of radiation doses established under this chapter.

DHS 157.03(111) (111) “Dose monitor unit" means a unit response from the beam monitoring system from which the absorbed dose may be calculated.

DHS 157.03(112) (112) “Dose profile" means the dose as a function of position along a line.

DHS 157.03(113) (113) “Dosimeter" means a recording device used to measure exposure to ionizing radiation.

DHS 157.03(114) (114) “Dosimetry processor" means an individual or an organization that processes and evaluates individual monitoring devices to determine the radiation dose delivered to the monitoring devices.

DHS 157.03(115) (115) “Doubly encapsulated sealed source" means a sealed source in which the radioactive material is sealed within an inner capsule and that capsule is sealed within an outer capsule.

DHS 157.03(116) (116) “Effective dose equivalent" or “EDE" means the sum of the products of the dose equivalent to each organ or tissue and the weighting factor applicable to each of the body organs or tissues that are irradiated (HE = ∑ wTHT).

DHS 157.03 Note Note: Effective dose equivalent (HE) equals the sum of the weighting factor (wT) times the dose equivalent to each organ or tissue (HT).

DHS 157.03(117) (117) “Electron microscope" means a microscope utilizing electrons to provide high magnification examination of materials.

DHS 157.03(118) (118) “Elemental area" means the smallest area within a tomogram for which the x-ray attenuation properties of a body are depicted.

DHS 157.03(119) (119) “Embryo or fetus" means the developing human organism from conception until the time of birth.

DHS 157.03(120) (120) “Emergency" means an event requiring prompt action to mitigate a threat to the health and safety of workers and the public or a threat of damage to the environment.

DHS 157.03(121) (121) “Energy compensation source" or “ECS" means a small sealed source, with an activity not exceeding 3.7 MBq (100 microcuries), used within a well logging tool, or other tool components, to provide a reference standard to maintain the well logging tool's calibration when in use.

DHS 157.03(122) (122) “Enriched uranium" means uranium containing more uranium-235 than the naturally occurring distribution of uranium isotopes.

DHS 157.03(123) (123) “Entrance air kerma rate" means the air kerma free in air per unit time at the point where the center of the useful beam enters the patient.

DHS 157.03(124) (124) “Entrance or access point" means any location through which an individual could gain access to radiation areas or to licensed or registered radioactive materials. This includes entry or exit portals of sufficient size to permit human entry, irrespective of their intended use.

DHS 157.03(124g) (124g) “Escorted access" means the continuous direct visual surveillance by an approved individual over an individual in the security zone who is not approved for unescorted access.

DHS 157.03(124m) (124m) “Exclusive use" means the sole use by a single consignor of a conveyance for which all initial, intermediate, and final loading and unloading are carried out in accordance with the direction of the consignor or consignee. The consignor and the carrier must ensure that any loading or unloading is performed by personnel having radiological training and resources appropriate for the safe handling of the consignment. The consignor shall issue specific instructions, in writing, for maintenance of exclusive use shipment controls, and include them with the shipping paper information provided to the carrier by the consignor.

DHS 157.03(125) (125) “Explosive material" means any chemical compound, mixture or device that produces a substantial instantaneous release of gas and heat spontaneously or by contact with sparks or flame.

DHS 157.03(126) (126) “Exposure" means the quotient of dQ divided 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 liberated by photons in a volume element of air having mass “dm" are completely stopped in air. The SI unit of exposure is the coulomb per kilogram. The standard unit of exposure is the roentgen.

DHS 157.03(127) (127) “Exposure head" means a device that locates the gamma radiography sealed source in the selected working position.

DHS 157.03(128) (128) “Exposure rate" means the exposure per unit of time, such as roentgen per minute and milliroentgen per hour.

DHS 157.03(129) (129) “External beam radiation therapy" means therapeutic irradiation in which the source of radiation is at a distance from the body.

DHS 157.03(130) (130) “External dose" means that portion of the dose equivalent received from any source of radiation outside the body.

DHS 157.03(131) (131) “External sinking fund" means an account, segregated from licensee assets and outside the licensee's administrative control, into which monies are periodically deposited that are sufficient to pay decommissioning costs expected at the time licensee operations are terminated.

DHS 157.03(132) (132) “Extremity" means hand, elbow, arm below the elbow, foot, knee and leg below the knee.

DHS 157.03(133) (133) “Extremity bone densitometer" means a device that tests the mineral content of the bone of the fore arm, hand or foot.

DHS 157.03(134) (134) “FDA" means the U.S. food and drug administration.

DHS 157.03(135) (135) “Field emission equipment" means equipment that uses an x-ray tube in which electron emission from the cathode is due solely to the action of an electric field.

DHS 157.03(136) (136) “Field station" means a facility where radioactive sources may be stored or used and from which equipment is dispatched to temporary job sites.

DHS 157.03(137) (137) “Film badge" means a dosimeter containing radiation sensitive photographic film for measuring radiation dose plus various filters that characterize the type of radiation encountered. When developed, the darkness of the film is directly proportional to the amount of radiation received.

DHS 157.03(138) (138) “Filter" means material placed in the useful beam to preferentially absorb selected radiation energies.

DHS 157.03(139) (139) “Filtering facepiece" means a negative pressure respirator with a filter as an integral part of the facepiece or with the entire facepiece composed of the filtering medium, not equipped with elastomeric sealing surfaces and adjustable straps.