DHS 157.78(1)(1) General. In addition to the provisions of ss. DHS 157.74 and 157.75, the requirements in this section apply to x-ray equipment and associated facilities used for dental radiography. Requirements for extraoral dental radiographic systems are contained in s. DHS 157.77. DHS 157.78(2)(2) Source-to-skin distance. X-ray systems designed for use with an intraoral image receptor shall be provided with means to limit source-to-skin distance to not less than either one of the following: DHS 157.78(2)(a)(a) 20 centimeters (8 inches) if operable above 50 kVp. Beam-limiting devices shall be lead lined. DHS 157.78(2)(b)(b) 10 centimeters (4 inches) if operable at 50 kVp only. Beam-limiting devices shall be lead lined. DHS 157.78(3)(3) Beam limitation. Radiographic systems designed for use with an intraoral image receptor shall be provided with means to limit the x-ray beam such that the beam at the minimum SSD shall be contained in a circle having a diameter of no more than 7 centimeters. DHS 157.78(4)(4) Radiation exposure control. Intraoral radiographic systems shall meet all of the following exposure control requirements: DHS 157.78(4)(a)(a) Exposure initiation. Means shall be provided to initiate the radiation exposure by a deliberate action on the part of the operator, such as the depression of a switch. Radiation exposure may not be initiated without such an action. An exposure may not be made when the timer is set to a “zero” or “off” position if either position is provided. DHS 157.78(4)(b)(b) Exposure indication. Means shall be provided for visual exposure indication observable at or from the operator’s protected position whenever x-rays are produced. In addition, a signal audible to the operator shall indicate that the exposure has terminated. DHS 157.78(4)(c)(c) Exposure termination. Means shall be provided to terminate the exposure at a preset time interval, preset product of current and time, a preset number of pulses or a preset radiation exposure to the image receptor. Termination of an exposure shall cause automatic resetting of the timer to its initial setting or to “zero” except for panoramic systems that may pause during the exposure cycle. DHS 157.78(4)(d)(d) Exposure control location and operator protection. An x-ray system shall meet all the following requirements, as applicable, to ensure operator protection during use of the system: DHS 157.78(4)(d)1.1. A stationary x-ray system shall have an x-ray exposure control that is operable from behind a protective barrier during the entire exposure. The exposure control cord shall be of sufficient length to allow the operator to be at least 2 meters (6.5 feet) from the x-ray tube head and not in the direction of the primary beam. The operator shall be able to determine when the exposure has completed either by audible tone or visible signal. DHS 157.78(4)(d)2.2. A mobile or portable x-ray system that is used for greater than one week in the same location, which is a room or suite, shall meet the requirements of stationary dental equipment. DHS 157.78(4)(d)3.3. A mobile or portable x-ray system that is used for less than one week in the same location shall be provided with either a protective barrier at least 2 meters (6.5 feet) high for operator protection or means to allow the operator to be at least 2 meters (6.5 feet) from the tube housing assembly during exposures. DHS 157.78(5)(5) Reproducibility. When the equipment is operated on an adequate power supply as specified by the manufacturer, the estimated coefficient of variation of air kerma may be no greater than 0.05 for any specific combination of selected technique factors. DHS 157.78(6)(6) mA/mAs linearity. X-ray equipment that is operated on a power supply as specified by the manufacturer for any fixed x-ray tube potential within the range of 40% to 100% of the maximum rated shall meet all of the following requirements: DHS 157.78(6)(a)(a) Equipment having independent selection of x-ray tube current. The average ratios of air kerma to the indicated milliampere-seconds product, in units of .001 mGy/mAs (mR/mAs), obtained at any 2 consecutive tube current settings may not differ by more than 0.10 times their sum: X1 - X2 < 0.10 (X1+X2)
where X1 and X2 are the average values obtained at each of 2 consecutive tube current settings, or at 2 settings differing by no more than a factor of 2 where the tube current selection is continuous.
DHS 157.78(6)(b)(b) Equipment having a combined x-ray tube current-exposure time product selector but not a separate tube current selector. The average ratios of air kerma to the indicated milliampere-seconds product, in units of .001 mGy/mAs (mR/mAs), obtained at any 2 consecutive mAs selector settings may not differ by more than 0.10 times their sum: X1 - X2 < 0.10 (X1 +X2)
where X1 and X2 are the average values obtained at any 2 consecutive mAs selector settings, or at 2 settings differing by no more than a factor of 2 where the mAs selector provides continuous selection.
DHS 157.78(6)(c)(c) Measuring compliance. Determination of compliance shall be based on 10 exposures taken within a time period of one hour at each of the 2 settings. The 2 settings may include any 2 focal spot sizes except where one is equal to or less than 0.45 millimeters and the other is greater than 0.45 millimeters. For purposes of this requirement, focal spot size is the nominal focal spot size specified by an x-ray tube manufacturer. DHS 157.78(7)(7) Accuracy. Deviation of technique factors from indicated values for kVp and exposure time, if time is independently selectable, may not exceed the limits specified for that system by its manufacturer. In the absence of manufacturer’s specifications the deviation may not exceed 10% of the indicated value for kVp and 10% for time. DHS 157.78(8)(8) kVp limitations. Dental x-ray machines with a nominal fixed kVp of less than 50 kVp may not be used to make diagnostic dental radiographs of humans. DHS 157.78(9)(b)(b) The tube housing and the cone may not be hand-held during an exposure. DHS 157.78(9)(c)(c) The tube shall be stationary during exposure, except for panoramic systems. Any oscillation of the tube head shall cease before exposure is made. DHS 157.78(10)(10) Hand-held intraoral dental radiographic units. A dental radiographic unit that is designed to be operated as a hand-held unit shall meet all the following requirements: DHS 157.78(10)(a)1.1. Operators of hand-held intraoral dental radiographic units shall be trained to operate such equipment. The training shall cover: manufacturer specific exposure control, use of safety devices, operator and patient protection, and quality control testing. DHS 157.78(10)(a)2.2. When operating a hand-held intraoral dental radiographic unit, operators shall wear a lead apron and thyroid collar unless the hand-held intraoral device has a secondary protective barrier. DHS 157.78(10)(a)3.3. A hand-held intraoral dental radiographic unit shall be immobilized during a patient examination. A tube stand may be utilized to immobilize a hand-held intraoral dental radiographic unit during patient examination. DHS 157.78(10)(a)4.4. The operator shall ensure there are no bystanders within a radius of at least 2 meters (6.5 ft) from the patient being examined during exposures. DHS 157.78(10)(b)1.1. Hand-held intraoral dental radiographic units shall be used for patient examinations in dental offices that meet the structural shielding requirements specified by the department. DHS 157.78(10)(b)2.2. Hand-held intraoral dental radiographic units may not be used for patient examinations in hallways and waiting rooms. DHS 157.78 HistoryHistory: CR 01-108: cr. Register July 2002 No. 559, eff. 8-1-02; CR 16-078: am. (4) (d) 1., 3., (8) (title), (9) (a), cr. (10) Register January 2018 No. 745, eff. 2-1-18. DHS 157.79DHS 157.79 Veterinary medicine x-ray systems. DHS 157.79(1)(1) General. The requirements of this section apply to all animal use x-ray systems used in veterinary practice and are in addition to other provisions in subchs. I and III. DHS 157.79(2)(a)(a) The tube housing shall be electrically shock proof and of a diagnostic type. The x-ray tube may not be hand-held during exposures. DHS 157.79(2)(b)(b) A device shall be provided to terminate the exposure after a preset time or exposure. DHS 157.79(2)(c)(c) A dead-man type of exposure switch shall be provided with an electrical cord of sufficient length so that the operator or the assistant, may stand out of the useful beam and at least 2 meters (6.5 feet) from the table during all x-ray exposures. A foot operated exposure switch may be used and this switch may be integrated into the table base or the foot switch may be on a 2 meter (6.5 feet) cord. DHS 157.79(3)(a)(a) The operator shall stand at least 2 meters (6.5 feet) from the tube housing and the animal during radiographic exposures. The operator may not stand in the useful beam. Hand-held fluoroscopic screens may not be used. The tube housing may not be held by the operator. No person other than the operator may be in an x-ray room while exposures are being made unless another person’s assistance is required. DHS 157.79(3)(b)(b) During any application in which the operator is not located behind a protective barrier, the operator and any other persons in the room during exposures shall wear protective clothing consisting of a protective apron having a lead equivalent of not less than 0.5 millimeter unless measurements indicate otherwise. DHS 157.79(3)(c)(c) Any person holding or supporting an animal or the image receptor during radiation exposure shall wear protective gloves that surround the hand and a protective apron having a lead equivalent of not less than 0.25 millimeter. Devices that only partially shield the hands are prohibited. DHS 157.79(3)(d)(d) Veterinary fluoroscopy systems shall be operated only under the direct supervision of the licensed veterinarian. DHS 157.79(4)(4) Animal support. Mechanical restraints shall be used to restrict movement of the animal unless the restraints interfere with the examination of the animal. No persons may be regularly utilized to hold or support animals during radiation exposures. Operating personnel may not perform this service except in cases where no other person is available. DHS 157.80DHS 157.80 Computed tomography x-ray systems. DHS 157.80(1)(1) Equipment requirements. A computed tomography (CT) x-ray system shall meet all of the following requirements, as applicable: DHS 157.80(1)(a)1.1. Means shall be provided to terminate the x-ray exposure automatically by either de-energizing the x-ray source or shuttering the x-ray beam in the event of equipment failure affecting data collection. The termination shall occur within an interval that limits the total scan time to no more than 110% of its preset value through the use of either a back-up timer or devices which monitor equipment function. A visible signal shall indicate when the x-ray exposure has been terminated. The operator shall be able to terminate the x-ray exposure at any time during a scan, or series of scans under CT x-ray system control, of greater than one-half second duration. DHS 157.80(1)(a)2.2. For systems that allow high voltage to be applied to the x-ray tube continuously and that control the emission of x-ray with a shutter, the radiation emitted may not exceed 0.88 mGy (100mR) in 1 hour at any point 5 centimeters outside the external surface of the housing of the scanning mechanism when the shutter is closed. DHS 157.80(1)(a)3.3. Compliance shall be determined by measurements averaged over an area of 100 square centimeters with no linear dimension greater than 20 centimeters. DHS 157.80(1)(b)1.1. A single tomogram system shall allow for visual determination of the tomographic plane or a reference plane offset from the tomographic plane. DHS 157.80(1)(b)2.2. A multiple tomogram system shall allow for visual determination of the location of a reference plane. DHS 157.80 NoteNote: The reference plane may be offset from the location of the tomographic planes.
DHS 157.80(1)(b)3.3. If a device using a light source is used to satisfy the requirements in subd. 2., the light source shall provide illumination levels sufficient to permit visual determination of the location of the tomographic plane or reference plane under ambient light conditions of up to 500 lux. DHS 157.80(1)(c)1.1. The CT x-ray control and gantry shall provide visual indication whenever x-rays are produced and, if applicable, whether the shutter is open or closed. Each emergency button or switch shall be clearly labeled as to its function. DHS 157.80(1)(c)2.2. For systems that allow high voltage to be applied to the x-ray tube continuously and that control the emission of x-ray with a shutter, the radiation emitted may not exceed 0.88 mGy (100 mR) in one hour at any point 5 cm outside the external surface of the housing of the scanning mechanism when the shutter is closed. DHS 157.80(1)(c)3.3. Compliance shall be determined by measurements averaged over an area of 100 square cm with no linear dimension greater than 20 cm. DHS 157.80(1)(d)(d) Indication of CT conditions of operation. A CT x-ray system shall be designed such that the CT conditions of operation to be used during a scan or a scan sequence shall be indicated prior to the initiation of the scan or a scan sequence. On equipment having all or some of these conditions of operation at fixed values, this requirement may be met by permanent markings. Indication of CT conditions of operation shall be visible from any position from which scan initiation is possible. DHS 157.80(1)(e)(e) Maximum surface CTDI100 identification. The angular position where the maximum surface CTDI100 occurs shall be identified to allow for reproducible positioning of a CT dosimetry phantom. DHS 157.80(1)(f)(f) CT x-ray systems containing a gantry manufactured after September 3, 1985. A computed tomography x-ray system containing a gantry that was manufactured after September 3, 1985, shall meet all the following requirements: DHS 157.80(1)(f)1.1. The total error in the indicated location of the tomographic plane or reference plane may not exceed 5 millimeters. DHS 157.80(1)(f)2.2. If the x-ray production period is less than one-half second, the indication of x-ray production shall be actuated for at least one-half second. Indicators at or near the gantry shall be discernible from any point external to the patient opening where insertion of any part of the human body into the primary beam is possible. DHS 157.80(1)(f)3.3. The deviation of indicated scan increment versus actual increment may not exceed plus or minus one millimeter with any mass from 0 to 100 kilograms resting on the support device. The patient support device shall be incremented from a typical starting position to the maximum incremented distance or 30 centimeters, whichever is less, and then returned to the starting position. Measurement of actual versus indicated scan increment may be taken anywhere along this patient support device movement distance. DHS 157.80(1)(f)4.4. Premature termination of the x-ray exposure by the operator shall necessitate resetting of the CT conditions of operation prior to the initiation of another scan. DHS 157.80(1)(f)5.5. Two-way aural communication shall exist between the patient and the operator at the control panel. DHS 157.80(1)(f)6.6. A viewing window, or viewing system, such as closed circuit television or an equivalent, shall be installed to permit continuous observation of the patient during irradiation. The window or viewing system shall be installed such that the operator, located at the control position, can continuously observe the patient during irradiation. When the primary viewing system is electronic, an alternative system shall be available for use in the event of failure of the primary viewing system. DHS 157.80(2)(a)1.1. A CT x-ray system for human use may only be operated for diagnostic procedures by an American registry of radiologic technologists certified person who is licensed as a radiographer by the State of Wisconsin or has met the radiographer license exemptions and has been specifically trained in its operation. DHS 157.80(2)(a)2.2. A CT x-ray system for veterinary use may only be operated for diagnostic procedures by a person who is certified by the American registry of radiological technologists or has completed training equivalent to the requirements of ch. DHS 157 Appendix L and has been specifically trained in its operation. DHS 157.80(2)(a)3.3. Combination systems which combine CT with another imaging device that uses radioactive material shall be operated by a person qualified by training in the safe use of radioactive materials and who meets the training requirements of ch. DHS 157 Appendix L. DHS 157.80(2)(b)(b) Information shall be available at the control panel regarding the operation and calibration of the system. The information shall include all of the following components: DHS 157.80(2)(b)1.1. Dates of the latest calibration and spot checks and the location within the facility where the results of those tests may be obtained. DHS 157.80(2)(b)2.2. Instructions on the use of the CT dosimetry phantom including a schedule of spot checks appropriate for the system, allowable variations for the indicated parameters and the results of at least the most recent spot checks conducted on the system. DHS 157.80(2)(b)3.3. The distance in millimeters between the tomographic plane and the reference plane if a reference plane is utilized. DHS 157.80(2)(b)4.4. A current technique chart or list of protocols available at the control panel, which specifies for each routine examination the CT conditions of operation and the number of scans per examination including body part size and correct kV/mA for that body part. The technique chart or a list of protocols shall be used to adjust techniques based on the body part being examined. DHS 157.80(2)(c)(c) Calibration and spot check measurements shall be made at a frequency recommended by the manufacturer or established by a medical physicist. If the calibration or spot check of the CT x-ray system identifies that a system operating parameter has exceeded a tolerance established by the medical physicist, use of the CT x-ray system on patients shall be limited to those uses permitted by established written instructions of the medical physicist. DHS 157.80(2)(d)(d) A facility shall follow the manufacturer’s daily start up routines and preventative maintenance schedules for a specific computed tomography x-ray system. DHS 157.80 HistoryHistory: CR 01-108: cr. Register July 2002 No. 559, eff. 8-1-02; CR 06-021: renum. (1) (a) and (c) to be (1) (a) 1. and (c) 1., cr. (1) (a) 2. and 3. and (c) 2. and 3., am. (2) (a) Register October 2006 No. 610, eff. 11-1-06; CR 09-062: renum. (2) (a) to be (2) (a) 1. and 3. and am., cr. (2) (a) 2. Register April 2010 No. 652, eff. 5-1-10; CR 16-078: r. (1) (b) (intro.), cr. (1) (f) 5., 6., am. (2) (a) 1., (b) 4., (c) Register January 2018 No. 745, eff. 2-1-18; correction in (2) (a) 2., 3. made under s. 35.17, Stats., Register January 2018 No. 745; CR 22-015: am. (1) (c) 2. Register June 2023 No. 810, eff. 7-1-23.
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Chs. DHS 110-199; Health
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