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:

m

m

m

where:

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

m

= linear attenuation coefficient of the material of interest;

m

= 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.