DHS 157.76(10)
(10)
Displays of values of air kerma rate and cumulative air kerma. Fluoroscopic equipment manufactured on or after June 10, 2006, shall display at the fluoroscopist's working position the air kerma rate and cumulative air kerma. Each x-ray tube used during an examination or procedure shall meet all the following requirements:
DHS 157.76(10)(a)
(a) When the x-ray tube is activated and the number of images produced per unit time is greater than 6 images per second, the air kerma rate in mGy/min shall be continuously displayed and updated at least once every second.
DHS 157.76(10)(b)
(b) The cumulative air kerma in units of mGy shall be displayed either within 5 seconds of termination of an exposure or displayed continuously and updated at least once every 5 seconds.
DHS 157.76(10)(c)
(c) The display of the air kerma rate shall be clearly distinguishable from the display of the cumulative air kerma.
DHS 157.76(10)(d)1.1. The air kerma rate and cumulative air kerma shall represent the value for conditions of free-in-air irradiation at one of the referenced locations.
DHS 157.76(10)(d)2.
2. For fluoroscopes with x-ray source below the x-ray table, x-ray source above the table, or of lateral type, the reference locations shall be the respective locations specified in sub.
(4) for measuring compliance with air kerma rate limits.
DHS 157.76(10)(d)3.
3. For C-arm fluoroscopes, the reference location shall be 15 cm from the isocenter toward the x-ray source along the beam axis. Alternatively, the reference location shall be at a point specified by the manufacturer to represent the location of the intersection of the x-ray beam with the patient's skin.
DHS 157.76 Note
Note: The reference location is identified and described specifically in the information provided to users according to
21 CFR 1020.30 (h) (6) (iii).
DHS 157.76(10)(e)
(e) Means shall be provided to reset to zero the display of cumulative air kerma prior to the commencement of a new examination or procedure.
DHS 157.76(10)(f)
(f) The displayed air kerma rate and cumulative air kerma shall not deviate from the actual values by more than
±35 percent over the range of 6 mGy/min and 100 mGy to the maximum indication of air kerma rate and cumulative air kerma, respectively. Compliance shall be determined with an irradiation time greater than 3 seconds.
DHS 157.76(11)(a)(a) The registrant shall ensure that only a licensed practitioner or a radiologic technologist who is trained in the safe use of fluoroscopic x-ray systems is allowed to operate these systems. All fluoroscopic x-ray images shall be viewed, directly or indirectly, and interpreted by a licensed practitioner.
DHS 157.76(11)(b)
(b) The use of fluoroscopic x-ray systems by radiologic technologists shall be performed under the supervision of a licensed practitioner for the purpose of localization to obtain images for diagnostic purposes.
DHS 157.76(11)(c)
(c) Radiologic technology students may not operate fluoroscopic x-ray systems except under the direct supervision of a licensed practitioner or radiologic technologist.
DHS 157.76(11)(d)
(d) Fluoroscopic x-ray systems may not be used as a positioning tool for general purpose radiographic examinations.
DHS 157.76(11)(e)
(e) The registrant shall require the operator of a fluoroscopic x-ray system to meet either of the following requirements:
DHS 157.76(12)
(12)
Air kerma measurements. Annual measurements of both typical and maximum air kerma shall be made by a medical physicist or a person approved by a medical physicist.
DHS 157.76 Note
Note: Materials should be placed in the useful beam to protect the imaging system when conducting these periodic measurements. Air kerma measurements do not include backscatter.
DHS 157.76 History
History: CR 01-108: cr.
Register July 2002 No. 559, eff. 8-1-02;
CR 06-021: r. and recr.
Register October 2006 No. 610, eff. 11-1-06;
CR 09-062: cr. (11) and (12)
Register April 2010 No. 652, eff. 5-1-10;
CR 16-078: r. and recr. (7) (c), cr. (7) (d), am. (11) (a)
Register January 2018 No. 745, eff. 2-1-18; correction in (7) (c) 2. made under s.
35.17, Stats.,
Register January 2018 No. 745;
CR 22-015: am. (intro.), (2) (b), (8) Register June 2023 No. 810, eff. 7-1-23. DHS 157.77
DHS 157.77 General purpose radiographic systems. DHS 157.77(1)(a)(a)
Collimation. The useful beam shall be limited to the area of clinical interest. This requirement is met if a positive beam-limiting device meeting manufacturer's specifications has been properly used or if evidence of collimation is shown on at least 3 sides or 3 corners of the film. Mammography systems are exempt from the collimation requirement.
DHS 157.77(1)(b)
(b)
General purpose stationary and mobile x-ray systems. General purpose stationary and mobile x-ray systems, including veterinary systems other than portable, shall meet both of the following requirements:
DHS 157.77(1)(b)1.
1. Only x-ray systems provided with means for independent stepless adjustment of at least 2 dimensions of the x-ray field may be used.
DHS 157.77(1)(b)2.
2. A method shall be provided for visually defining the perimeter of the x-ray field. The total misalignment of the edges of the visually defined field with the respective edges of the x-ray field along either the length or width of the visually defined field may not exceed 2% of the distance from the source to the center of the visually defined field when the surface upon which it appears is perpendicular to the axis of the x-ray beam.
DHS 157.77(1)(c)
(c)
Stationary general purpose x-ray systems. Stationary general purpose x-ray systems, both certified and non-certified, shall meet all the following requirements:
DHS 157.77(1)(c)1.
1. A method shall be provided to indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor, to align the center of the x-ray field with respect to the center of the image receptor to within 2% of the SID and to indicate the SID to within 2%.
DHS 157.77(1)(c)2.
2. The beam-limiting device shall indicate numerically the field size in the plane of the image receptor to which it is adjusted.
DHS 157.77(1)(c)3.
3. Field size dimensions and SIDs shall be specified in inches or centimeters and shall ensure that aperture adjustments result in x-ray field dimensions in the plane of the image receptor that correspond to those indicated by the beam-limiting device to within 2% of the SID when the beam axis is indicated to be perpendicular to the plane of the image receptor.
DHS 157.77(1)(d)
(d)
X-ray systems designed for one image receptor size. Radiographic equipment designed for only one image receptor size at a fixed SID shall be provided with means to limit the field at the plane of the image receptor to dimensions no greater than those of the image receptor, and to align the center of the x-ray field with the center of the image receptor to within 2% of the SID, or shall be provided with means to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor.
DHS 157.77(1)(e)
(e)
Miscellaneous and veterinary x-ray systems. X-ray systems other than those described in pars.
(a) to
(c), veterinary systems installed prior to the effective date of August 1, 2002, and all portable veterinary x-ray systems shall meet all of the following requirements:
DHS 157.77(1)(e)1.
1. Means shall be provided to limit the x-ray field in the plane of the image receptor so that such field does not exceed each dimension of the image receptor by more than 2% of the SID when the axis of the x-ray beam is perpendicular to the plane of the image receptor.
DHS 157.77(1)(e)2.
2. Means shall be provided to align the center of the x-ray field with the center of the image receptor to within 2% of the SID, or means shall be provided to both size and align the x-ray field such that the x-ray field at the plane of the image receptor does not extend beyond any edge of the image receptor. Compliance shall be determined with the axis of the x-ray beam perpendicular to the plane of the image receptor.
DHS 157.77(1)(e)3.
3. The requirements in subds.
1. and
2. may be met with a collimator system that meets the requirements for a general purpose x-ray system or, when alignment means are also provided, may be met with either of the following:
DHS 157.77(1)(e)3.a.
a. An assortment of removable, fixed-aperture, beam-limiting devices sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed with each such device having clear and permanent markings to indicate the image receptor size and SID for which it is designed.
DHS 157.77(1)(e)3.b.
b. A beam-limiting device with multiple fixed apertures sufficient to meet the requirement for each combination of image receptor size and SID for which the unit is designed. Permanent, clearly legible markings shall indicate the image receptor size and SID that each aperture is designed for and shall indicate which aperture is in position for use.
DHS 157.77(2)(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. In addition, exposure may not be initiated when the timer is set to a “zero" or “off" position if either position is provided.
DHS 157.77(2)(b)
(b)
Exposure indication. Means shall be provided for visual 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 157.77(2)(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. Except for dental panoramic systems, termination of an exposure shall cause automatic resetting of the timer to its initial setting or to “zero."
DHS 157.77(2)(d)
(d)
Manual exposure control. An x-ray control shall be incorporated into each x-ray system so that the operator may terminate an exposure at any time except for any one of the following:
DHS 157.77(2)(d)2.
2. During serial radiography when means shall be provided to permit completion of any single exposure of the series in process.
DHS 157.77(2)(e)
(e)
Automatic exposure controls. When an automatic exposure control is provided, it shall meet all the following requirements:
DHS 157.77(2)(e)1.
1. Indication shall be made on the control panel when this mode of operation is selected.
DHS 157.77(2)(e)2.
2. If the x-ray tube potential is equal to or greater than 50 kVp, the minimum exposure time for field emission equipment rated for pulsed operation shall be equal to or less than a time interval equivalent to 2 pulses.
DHS 157.77(2)(e)3.
3. The minimum exposure time for all equipment other than field emission equipment shall be equal to or less than one-sixtieth second or a time interval required to deliver 5 mAs, whichever is greater.
DHS 157.77(2)(e)4.
4. Either the product of peak x-ray tube potential, current, and exposure time shall be limited to not more than 60 kWs per exposure, or the product of x-ray tube current and exposure time shall be limited to not more than 600 mAs per exposure except that, when the x-ray tube potential is less than 50 kVp, the product of x-ray tube current and exposure time shall be limited to not more than 2000 mAs per exposure.
DHS 157.77(2)(e)5.
5. A visible signal shall indicate when an exposure has been terminated and manual resetting shall be required before further automatically timed exposures may be made.
DHS 157.77(2)(f)
(f)
Exposure duration linearity. For systems having independent selection of exposure time settings, the average ratios of exposure to the indicated timer setting, in units of .001mGy/s (mR/s), obtained at any 2 clinically used timer settings may not differ by more than 0.10 times their sum as expressed as:
(X1 - X2) < 0.1 (X1 + X2)
where X1 and X2 are the average .001 mGy/s (mR/s).
DHS 157.77(2)(g)
(g)
Exposure control location. The x-ray exposure control shall be placed so that the operator may view the patient while making any exposure and at least 1 meter (3.3 feet) from the end of the protective barrier.
DHS 157.77(2)(h)
(h)
Operator protection, except veterinary systems. X-ray systems, excluding veterinary systems, shall meet all the following requirements to protect the operator during system use, as applicable:
DHS 157.77(2)(h)1.
1. Stationary x-ray systems shall be required to have the x-ray control permanently mounted behind a protective barrier such that the operator is required to remain behind the protective barrier during the entire exposure.
DHS 157.77(2)(h)2.
2. Mobile and portable x-ray systems used continuously for greater than one week in the same location shall meet the requirements of stationary systems.
DHS 157.77(2)(h)3.
3. Mobile and portable x-ray systems used for less than one week at the same location shall be provided with either a protective barrier at least 2 meters (6.5 feet) high for operator protection during exposures or a means to allow the operator to be at least 2 meters (6.5 feet) from the tube housing assembly during the exposure.
DHS 157.77(2)(i)
(i)
Operator protection for veterinary systems. All stationary, mobile or portable x-ray systems used for veterinary work shall be provided with either a 2 meter (6.5 feet) high protective barrier for operator protection during exposures or a means to allow the operator to be at least 2 meters (6.5 feet) from the tube housing assembly during exposures. Persons within 2.7 meters (9 feet) of the tube or animal during exposures shall be protected with at least 0.25mm lead aprons. Persons restraining the animal during radiography shall be protected with at least 0.25mm lead aprons and full coverage gloves or full coverage mittens containing not less than 0.5mm lead equivalent material. The exposure control may be foot operated.
DHS 157.77(3)
(3)
Source-to-skin distance. All mobile or portable radiographic systems shall be provided with means to limit the source-to-skin distance to equal to or greater than 30 centimeters, except for veterinary systems.
DHS 157.77(4)
(4)
Air kerma reproducibility. When all technique factors are held constant, including control panel selections associated with automatic exposure control systems, the coefficient of variation of air kerma for both manual and automatic exposure control systems may not exceed 0.05. This requirement applies to clinically used techniques.
DHS 157.77(5)
(5)
Radiation from capacitor energy storage equipment in standby status. Radiation emitted from the x-ray tube when the system is fully charged and the exposure switch or timer is not activated may not exceed any of the following:
DHS 157.77(5)(a)
(a) A rate of 0.26mGy (0.03mR exposure) in one minute at 5 centimeters from any accessible surface of the diagnostic source assembly with the beam-limiting device fully open.
DHS 157.77(5)(b)
(b) An air kerma of 0.88 mGy (100mr/exposure) in one hour at 100 centimeters from the x-ray source, with the beam-limiting device fully open, when the system is discharged through the x-ray tube either manually or automatically by use of a discharge switch or deactivation of the input power. Compliance shall be determined by measurements of the maximum air kerma per discharge multiplied by the total number of discharges in one hour (duty cycle). The measurements shall be averaged over an area of 100 square centimeters with no linear dimension greater than 20 centimeters.
DHS 157.77(6)
(6)
Accuracy. Deviation of measured technique factors from indicated values of kVp and exposure time 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% of the time limit.
DHS 157.77(7)
(7)
mA/m
As 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 the following requirements:
DHS 157.77(7)(a)
(a)
Equipment having independent selection of x-ray tube current (mA). The average ratios of exposure to the indicated milliampere-seconds product 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 any 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 157.77(7)(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 exposure 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 157.77(7)(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. These 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 157.77(8)
(8)
Additional requirements applicable to certified systems only. A diagnostic x-ray system incorporating one or more certified components shall meet all of the following additional requirements that relate to that certified component or components:
DHS 157.77(8)(a)
(a)
Beam limitation for stationary and mobile general purpose x-ray systems. Stationary and mobile general purpose x-ray systems shall meet all the following beam limitation requirements:
DHS 157.77(8)(a)1.
1. There shall be provided a means of stepless adjustment of the size of the x-ray field. The minimum field size at a SID of 100 centimeters shall be equal to or less than 5 centimeters by 5 centimeters.
DHS 157.77(8)(a)2.
2. When a light localizer type of collimator is used to define the x-ray field, it shall provide an average illumination of not less than 160 lux or 15 footcandles at 100 centimeters or at the maximum SID, whichever is less. The average illumination shall be based upon measurements made in the approximate center of each quadrant of the light field. Radiation therapy simulation systems manufactured on and after May 27, 1980, are exempt from this requirement.
DHS 157.77(8)(a)3.
3. The edge of the light field at 100 centimeters or at the maximum SID, whichever is less, shall have a contrast ratio, corrected for ambient lighting, of not less than 4 in the case of beam-limiting devices designed for use on stationary equipment, and a contrast ratio of not less than 3 in the case of beam-limiting devices designed for use on mobile equipment. The contrast ratio is defined as I
1/I
2 where I
1 is the illumination 3 millimeters from the edge of the light field toward the center of the field; and I
2 is the illumination 3 millimeters from the edge of the light field away from the center of the field. Compliance shall be determined with a measuring instrument aperture of one millimeter in diameter.
DHS 157.77(8)(b)
(b)
Beam limitation and alignment on stationary general purpose x-ray systems equipped with PBL. If PBL is being used, the x-ray system shall meet all of the following requirements:
DHS 157.77(8)(b)1.
1. PBL shall prevent the production of x-rays when either one of the following occurs:
