DHS 157.76(4)(e)4.4. In a C-arm type of fluoroscope having an source to image distance less than 45 cm, the air kerma rate shall be measured at the minimum source to skin distance.

DHS 157.76(4)(e)5.5. In a lateral type of fluoroscope, the air kerma rate shall be measured at a point 15 cm from the centerline of the x-ray table and in the direction of the x-ray source with the end of the beam limiting device or spacer positioned as closely as possible to the point of measurement. If the tabletop is movable, it shall be positioned as closely as possible to the lateral x-ray source, with the end of the beam-limiting device or spacer no closer than 15 cm to the centerline of the x-ray table.

DHS 157.76(5)(5) Indication of potential and current. During fluoroscopy and cinefluorography, x-ray tube potential and current shall be continuously indicated. Deviation of x-ray tube potential and current from the indicated values shall not exceed the maximum deviation as stated by the manufacturer in accordance with 21 CFR 1020.30 (h) (3).

DHS 157.76(6)(a)(a) Means shall be provided to limit the source to skin distance to not less than 38 cm on stationary fluoroscopes and to not less than 30 cm on mobile and portable fluoroscopes. In addition, for fluoroscopes intended for specific surgical application that would be prohibited at the source-skin distances specified in this paragraph, provisions may be made for operation at shorter source-skin distances but in no case less than 20 cm.

DHS 157.76(6)(b)(b) For stationary, mobile, or portable C-arm fluoroscopic systems manufactured on or after June 10, 2006, having a maximum source-image receptor distance of less than 45 cm, means shall be provided to limit the source-skin distance to not less than 19 cm. Such systems shall be labeled for extremity use only. In addition, for those systems intended for specific surgical application that would be prohibited at the source-skin distances specified in this paragraph, provisions may be made for operation at shorter source-skin distances but in no case less than 10 cm.

DHS 157.76(7)(a)(a) Fluoroscopic equipment manufactured before June 10, 2006, shall be provided with means to preset the cumulative irradiation time of the fluoroscopic tube. The maximum cumulative time of the timing device shall not exceed 5 minutes without resetting. A signal audible to the fluoroscopist shall indicate the completion of any preset cumulative Irradiation time. Such signal shall continue to sound while x-rays are produced until the timing device is reset.

DHS 157.76(7)(b)(b) As an alternative to the requirements of par. (a), radiation therapy simulation systems may be provided with a means to indicate the total cumulative exposure time during which x-rays were produced, and which is capable of being reset between x-ray examinations.

DHS 157.76(7)(c)(c) For x-ray controls manufactured on or after June 10, 2006, all of the following shall be provided for each fluoroscopic tube:

DHS 157.76(7)(c)2.2. The display required in subd. 1. shall function independently of the audible signal described in par. (a) and meet all the following requirements:

DHS 157.76(7)(c)2.a.a. When the x-ray tube is activated, the fluoroscopic irradiation time in minutes and tenths of minutes shall be continuously displayed and updated at least once every 6 seconds.

DHS 157.76(7)(c)2.b.b. The fluoroscopic irradiation time shall also be displayed within 6 seconds of termination of an exposure and remain displayed until reset.

DHS 157.76(7)(c)2.c.c. Means shall be provided to reset the display to zero prior to the beginning of a new examination or procedure.

DHS 157.76(7)(c)3.3. A signal audible to the fluoroscopist shall sound for each passage of 5 minutes of fluoroscopic irradiation time during an examination or procedure. The signal shall sound until manually reset or, if automatically reset, for at least 2 seconds.

DHS 157.76(7)(d)(d) If fluoroscopic equipment is modified in accordance with 21 CFR 1020.30(q) to comply with the requirements in par. (a), it shall bear a label that states:

DHS 157.76(8)(8) Mobile and portable fluoroscopes. Mobile and portable fluoroscopes shall use image-intensification or a direct-digital receptor.

DHS 157.76(9)(a)(a) Fluoroscopic equipment manufactured on or after June 10, 2006, shall be equipped with means to display the last image following termination of the fluoroscopic exposure.

DHS 157.76(9)(b)(b) For an LIH obtained by retaining pre-termination fluoroscopic images, if the number of images and method of combining images are selectable by the user, the selection shall be indicated prior to initiation of the fluoroscopic exposure.

DHS 157.76(9)(c)(c) For an LIH image obtained by initiating a separate radiographic-like exposure at the termination of fluoroscopic imaging, the technique factors for the LIH image shall be selectable prior to the fluoroscopic exposure, and the combination selected shall be indicated prior to initiation of the fluoroscopic exposure.

DHS 157.76(9)(d)(d) Means shall be provided to clearly indicate to the user whether a displayed image is the LIH radiograph or fluoroscopy. Display of the LIH radiograph shall be replaced by the fluoroscopic image concurrently with re-initiation of fluoroscopic exposure, unless separate displays are provided for the LIH radiograph and fluoroscopic images.

DHS 157.76(9)(e)(e) The predetermined or selectable options for producing the LIH radiograph shall be described in the information required by 21 CFR 1020.30 (h). The information shall include a description of any technique factors applicable for the selected option and the impact of the selectable options on image characteristics and the magnitude of radiation emissions.

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.