DHS 157.75DHS 157.75 General requirements for all diagnostic x-ray systems. Diagnostic x-ray systems shall meet all the following requirements: DHS 157.75(1)(1) Warning label. The control panel containing the main power switch shall bear the following warning statement, legible and accessible to view: “WARNING: This x-ray unit may be dangerous to patient and operator unless safe exposure factors and operating instructions are observed.” DHS 157.75(2)(2) Battery charge indicator. On battery-powered x-ray generators, visual means shall be provided on the control panel to indicate whether the battery is in a state of charge adequate for proper operation. DHS 157.75(3)(3) Leakage radiation from the diagnostic source assembly. The leakage radiation from the diagnostic source assembly measured at a distance of one meter in any direction from the source may not exceed one mGy (115 milliroentgens) in one hour when an x-ray tube is operated at its leakage technique factors. Compliance shall be determined by measurements averaged over an area of 100 square centimeters with no linear dimension greater than 20 centimeters. Leakage technique factors may be any of the following: DHS 157.75(3)(a)(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, which is 10 mAs, or the minimum obtainable from the unit, whichever is larger. DHS 157.75(3)(b)(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. DHS 157.75(3)(c)(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. DHS 157.75(4)(4) Radiation from components other than the diagnostic source assembly. The radiation emitted by a component other than the diagnostic source assembly may not exceed 20mGy (2.15 milliroentgens) in one hour at 5 centimeters from any accessible surface of the component when it is operated in an assembled x-ray system under any conditions for which it was designed. Compliance shall be determined by measurements averaged over an area of 100 square centimeters with no linear dimension greater than 20 centimeters. DHS 157.75(5)(a)(a) The half-value layer of the useful beam for a given x-ray tube potential may not be less than the values shown in Table DHS 157.75. If it is necessary to determine the half-value layer at an x-ray tube potential that is not listed in Table DHS 157.75, linear interpolation or extrapolation may be made. DHS 157.75(5)(b)(b) For x-ray systems using capacitor discharge to provide power to an x-ray tube, half-value layer shall be determined with the system fully charged and a setting of 10 mAs for each exposure. DHS 157.75(5)(c)(c) The required minimal half-value layer of the useful beam shall include the filtration contributed by all materials that are permanently between the source and the patient. DHS 157.75(5)(d)(d) For x-ray systems with variable filtration controls, the system shall prevent an exposure unless the appropriate filtration is in place for the kilovolts peak selected. DHS 157.75(6)(6) Multiple tubes. When 2 or more radiographic tubes are controlled by one exposure switch, the tube that has been selected shall be clearly indicated prior to initiation of the exposure. The indication shall be both on an x-ray control panel and at or near the selected tube housing assembly. DHS 157.75(7)(7) Mechanical support of tube head. The tube housing assembly supports shall be adjusted such that the tube housing assembly will remain stable during an exposure unless tube-housing movement is a designed function of an x-ray system. DHS 157.75(8)(a)(a) The technique factors to be used during an exposure shall be indicated before the exposure begins. If automatic exposure controls are used, the technique factors, which are set prior to the exposure, shall be indicated. DHS 157.75(8)(b)(b) The requirement in par. (a) may be met by permanent markings on equipment having fixed technique factors. Indication of technique factors shall be visible from the operator’s position except in the case of spot films made by the fluoroscopist. DHS 157.75(9)(9) Maintaining compliance. Diagnostic x-ray systems and their associated components used on humans and certified under the federal x-ray equipment performance standard, 21 CFR 1020, shall be maintained in compliance with applicable requirements of that standard. DHS 157.75(10)(10) Locks. All position locking, holding and centering devices on x-ray system components and systems shall function as intended. DHS 157.76DHS 157.76 Fluoroscopic equipment. Only image-intensified or direct-digital receptor fluoroscopic equipment shall be used for fluoroscopy. Equipment for fluoroscopic imaging or for recording images from the fluoroscopic image receptor, except computed tomography x-ray systems manufactured on or after November 29, 1984, shall meet all the following requirements: DHS 157.76(1)(a)(a) The fluoroscopic imaging assembly shall be provided with a primary protective barrier which intercepts the entire cross section of the useful beam at any source to image distance. The x-ray tube used for fluoroscopy shall not produce x-rays unless the barrier is in position to intercept the entire useful beam. The air kerma rate due to transmission through the barrier with the attenuation block in the useful beam combined with radiation from the fluoroscopic image receptor shall not exceed 3.34 x 10-3 percent of the entrance air kerma rate, at a distance of 10 cm from any accessible surface of the fluoroscopic imaging assembly beyond the plane of the image receptor. DHS 157.76(1)(b)1.1. The air kerma rate shall be measured as required under sub. (4). The air kerma rate due to transmission through the primary barrier combined with radiation from the fluoroscopic image receptor shall be determined by measurements averaged over an area of 100 square cm with no linear dimension greater than 20 cm. DHS 157.76(1)(b)2.2. If the source is below the tabletop, the measurement shall be made with the input surface of the fluoroscopic imaging assembly positioned 30 cm above the tabletop. If the source is above the tabletop and the source to image distance is variable, the measurement shall be made with the end of the beam-limiting device or spacer as close to the tabletop as it can be placed, provided that it shall not be closer than 30 cm. DHS 157.76(1)(b)3.3. Movable grids and compression devices shall be removed from the useful beam during the measurement. DHS 157.76(1)(b)4.4. For all measurements, the attenuation block shall be positioned in the useful beam 10 cm from the point of measurement of entrance air kerma rate and between this point and the input surface of the fluoroscopic imaging assembly.