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 NoteNote: 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 NoteNote: 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 “HT” 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:

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.