64E-5.504. Fluoroscopic X-Ray Systems

All fluoroscopic x-ray systems shall meet the following requirements:

(1) Limitation of the Useful Beam.

(a) The fluoroscopic tube shall not produce x-rays unless the primary protective barrier is in position to intercept the entire cross section of the useful beam.

(b) A means shall be provided between the x-ray source and the patient for stepless adjustment of the size of the x-ray field.

(c) With the collimating shutters adjusted to the closed position, the minimum field size at the maximum SID shall not be greater than 5 × 5 centimeters when measured at the point where the beam enters the patient.

(d) Limitation to the Imaging Surface.

1. The x-ray field produced by nonimage-intensified fluoroscopic equipment shall not extend beyond the useable area of the largest image receptor at any SID.

2. The longitudinal and transverse dimensions of the x-ray field produced by image-intensified fluoroscopic equipment shall not extend beyond the corresponding dimensions of the visible area of the image receptor by more than 3 percent of the SID in either dimension in the plane of the image receptor and the sum of the excess shall be no greater than 4 percent of the SID. If the collimation is automatically accomplished, the x-ray field dimension criteria above shall apply to all film sizes and portions thereof that the spot film device accommodates and to the dimensions of the input phosphor, as appropriate. If collimation is not automatic, the x-ray field dimension criteria shall apply to the useful area of the input phosphor.

3. Compliance shall be determined with the beam axis perpendicular to the plane of the image receptor. For rectangular x-ray fields used with circular image receptors, the error in alignment shall be determined along the length and width dimensions of the x-ray field which passes through the center of the visible area of the image receptor.

4. The center of the x-ray field in the plane of the image receptor shall be aligned with the center of the selected portion of the image receptor to within 2 percent of the SID.

5. Adjustable automatic and manual collimators shall operate smoothly throughout the entire range of use.

6. For fluoroscopic systems with spot film capability, means shall be provided for adjustment of the x-ray field size in the plane of the film to a size smaller than the selected portion of the film.

(e) The requirements of paragraph (1)(b) and (c), above, are not applicable to mobile fluoroscopic systems.

(2) Activation of the Fluoroscopic Tube. A control of the dead-man type shall be incorporated into each fluoroscopic system such that x-ray production will be terminated at any time pressure is released from the switch except during the recording of serial fluoroscopic images with equipment in which means have been provided to permit completion of any single exposure of the series in progress.

(3) Allowable Entrance Exposure Rate Limits for Fluoroscopic Equipment.

(a) Fluoroscopic equipment manufactured after June, 1995, operable at any combination of tube potential and current that results in an exposure rate greater than 5 roentgens (1.29 × 10-3 C per kg) per minute at the point where the center of the useful beam enters the patient shall be equipped with automatic exposure control. Provision for manual selection of technique factors can be provided.

(b) Fluoroscopic equipment shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 10 roentgens (2.58 × 10-3 C per kg) per minute at the point where the center of the useful beam enters the patient except:

1. During the recording of images from an x-ray image-intensifier tube using photographic film or a video camera when the x-ray source is operated in a pulsed mode.

2. When an optional high-level control is activated. When the high-level control is activated, the equipment shall not be operable at any combination of tube potential and current that will result in an exposure rate in excess of 20 roentgens (5.16 × 10-3 C per kg) per minute at the point where the center of the useful beam enters the patient. Special means to activate high-level controls shall be required. The high-level control shall only be operable when continuous manual activation is provided by the operator.

(c) Special means to activate high level controls such as additional pressure applied continuously by the operator shall be required to avoid accidental use.

(d) A continuous signal audible to the fluoroscopist shall indicate when the high level control is being employed.

(e) Compliance with the dose limits will be determined as follows:

1. Movable grids and compression devices will be removed from the useful beam during the measurement.

2. The fluoroscope’s radiation output will be maximized.

a. Systems with automatic exposure controls such as automatic brightness control will have sufficient lead or lead equivalent materials placed in the useful beam to produce the maximum output.

b. Systems without automatic exposure controls or systems with a manual mode in addition to automatic exposure control modes will have the current and potential set to produce the maximum output. Attenuating material will be placed in the useful beam to protect the imaging system. If the registrant has a written radiation protection program restricting the range of current and potential the tests will be performed within the range of allowed values.

c. Patient support device height and SID, where adjustable, will be varied to produce the maximum output. If the registrant has a written radiation protection program restricting the range of patient support device heights or SIDs the tests will be performed within the range of allowed values.

3. The exposure rate will be measured at the following points on the centerline of the beam unless the specified geometry is prohibited by a written radiation protection program.

a. At least one centimeter above the patient support device and corrected for distance to show the actual entrance exposure rate at the top surface of the patient support device for:

(I) Fluoroscopes where the x-ray tube is fixed under the patient support device.

(II) C-arm systems or stationary c-arm fluoroscopes where the x-ray tube can be rotated under the patient support device. The x-ray tube will be positioned as close to the patient support device as possible.

b. At 30 centimeters above the patient support device with the end of the beam-limiting device or spacer assembly positioned as close as possible to the point of measurement for:

(I) Fluoroscopes where the x-ray tube is fixed above the patient support device.

(II) C-arm systems or stationary c-arm fluoroscopes where the x-ray tube can be rotated above the patient support device.

c. At a point 15 centimeters laterally from the centerline of the patient support device or from the centerline of the patient if the registrant has a written radiation protection program specifying placement of the patient not on the centerline of the patient support device in the direction of the x-ray tube with the input surface of the fluoroscopic imaging assembly positioned as close to the edge of the patient support device as possible but no closer than 15 cm for:

(I) Fluoroscopes where the x-ray tube is fixed laterally to the patient support device.

(II) C-arm systems or stationary c-arm fluoroscopes where the x-ray tube can be rotated lateral to the patient support device.

d. At 30 centimeters from the input surface of the fluoroscopic imaging assembly, provided that the end of the beam-limiting device or spacer is no closer than 30 centimeters from the input surface of the fluoroscopic imaging assembly, for mobile c-arm fluoroscopes. Spacers or other attachments normally used can not be removed to allow measuring from a point closer to the actual input surface.

(f) Periodic Measurement of Entrance Exposure Rates. The entrance exposure rate shall be measured before use on humans after the completion of any initial or subsequent installation and after any maintenance of the system that might affect the exposure rate.

(g) For cinefluoroscopy, the maximum exposure at the face of the input phosphor with the grid removed and with an attenuation block in the beam shall not exceed 40 microroentgens (0.010 µC per kg) per frame. The maximum exposure shall be measured before use on humans after the completion of any initial or subsequent installation and after any maintenance of the system which might affect the maximum exposure.

(4) Barrier Transmitted Radiation Rate Limits.

(a) The exposure rate due to transmission through the primary protective barrier and frame assembly with the attenuation block in the useful beam combined with radiation from the image intensifier if provided shall not exceed 2 milliroentgens (0.516 µC per kg) per hour at 10 centimeters from any accessible surface of the fluoroscopic imaging assembly beyond the plane of the image receptor for each roentgen per minute of entrance exposure rate.

(b) Measuring Compliance with Barrier Transmission Limits.

1. The exposure rate due to transmission through the primary protective barrier combined with radiation from the image intensifier shall be determined by measurements averaged over an area no greater than 100 square centimeters with no linear dimension greater than 20 centimeters.

2. If the source is below the tabletop, the measurement shall be made with the input surface of the fluoroscopic imaging assembly positioned 30 centimeters above the tabletop.

3. If the source is above the tabletop and the SID is variable, the measurement shall be made with the end of the beam limiting device or spacer assembly as close to the tabletop as it can be placed but not closer than 30 centimeters.

4. Movable grids and compression devices shall be removed from the useful beam during the measurement.

5. The attenuation block shall be positioned in the useful beam 10 centimeters toward the input surface of the imaging assembly from the point at which the entrance exposure rate was measured.

6. The maximum beam size shall be used during measurements.

(5) Indication of Potential and Current. During fluoroscopy and cinefluorography, x-ray tube potential and current shall be continuously indicated.

(6) Source-to-Skin Distance. Positive means shall be provided to assure the source-to-skin distance shall not be less than:

(a) Thirty-eight centimeters on stationary fluoroscopes installed after January 1, 1977,

(b) Thirty-five and one-half centimeters on stationary fluoroscopes installed prior to January 1, 1977,

(c) Thirty centimeters on all mobile fluoroscopes,

(d) Twenty centimeters for image intensified fluoroscopes used for specific surgical applications. Written safety procedures must be provided to the operator of the fluoroscope and precautionary measures followed during the use of this device.

(e) Nineteen centimeters for extremity-use-only fluoroscopes.

(f) Ten centimeters for extremity-use-only fluoroscopes used for specific surgical applications. Written safety procedures must be provided to the operator of the fluoroscope and precautionary measures followed during the use of this device.

(7) Fluoroscopic Timer. A cumulative timing device activated by the fluoroscopic exposure switch shall be provided, the maximum cumulative time of which shall not exceed 5 minutes without resetting. The timer shall indicate the passage of the predetermined period of exposure by an audible signal or termination of the exposure. If such a signal is utilized, it shall continue while x-rays are produced until the timing device is reset.

(8) Mobile Fluoroscopes. In addition to the other requirements of this section, mobile fluoroscopes shall provide intensified imaging.

(9) Control of Scatter Radiation.

(a) Fluoroscopic table designs shall be such that scattered radiation which originates beneath the tabletop is attenuated by not less than 0.25 millimeters lead equivalent, and that no unprotected part of any staff or ancillary person’s body shall be exposed to unattenuated scattered radiation.

(b) Fluoroscopic equipment configuration shall be such that no portion of any staff or ancillary person’s body, except the extremities, shall be exposed to the unattenuated scattered radiation emanating from above the tabletop unless:

1. Such person is at least 120 centimeters from the center of the useful beam, or

2. The radiation has passed through not less than 0.25 millimeter lead equivalent material.

(c) Exceptions to paragraph (10)(b), above, may be made in some special procedures where a sterile field will not permit the use of the normal protective barriers. Where the use of prefitted sterilized covers for the barriers is practical, the Department shall not permit such exception.

(10) Photofluorographic Medical X-Ray Systems.

(a) In addition to other applicable sections of these regulations, photofluorographic x-ray systems shall conform with the following requirements:

1. Usage shall be limited to diagnostic radiography of the lungs and other soft tissues of the thoracic region.

2. Personnel monitoring shall be provided for all individuals who operate photofluorographic apparatus.

3. The average exposure, including backscatter, for chests measuring 25 centimeters in thickness shall not exceed 100 millirems (1.0 mSv) at the point where the x-ray beam enters the patient.

(b) Photofluorographic x-ray systems shall not be installed unless specifically approved by the Department.

(11) Radiation Therapy Simulation Systems. Radiation therapy simulation systems shall be exempt from all the requirements of subsections (1), (3), (4), (5) and (8), above, provided that:

(a) Such systems are designed and used in such a manner that no person other than the patient is in an unprotected area during periods of time when the system is producing x-rays; and

(b) Systems that do not meet the requirements of subsection (8), above, are provided with a means of indicating the cumulative time that an individual patient has been exposed to x-rays. In such cases, the timer shall be reset between examinations.

(c) The exposure rate measured at the point where the center of the useful beam enters the patient shall not exceed 20 roentgens (5.16 mC per kg) per minute, except during the recording of fluoroscopic images.

(12) For remotely operated fluoroscopic systems:

(a) The remote control panel shall be installed so as to require the operator to stand behind a permanent protective barrier meeting the requirements of paragraph 64E-5.502(2)(a)-(c), F.A.C. The barrier must be wide enough to prevent the secondary scatter radiation from striking the operator directly when the machine is operated from the remote control panel.

(b) The operator must be able to see and hear the patient when behind the barrier.

(c) The barrier shall be constructed of material of sufficient density to meet or exceed the barrier requirements of sub-subparagraph 64E-5.502(1)(a)4.b., F.A.C.

Rulemaking Authority 404.051, 404.22 FS. Law Implemented 404.051, 404.22 FS. History–New 7-17-85, Amended 4-4-89, 3-17-92, 1-5-95, Formerly 10D-91.605, Amended 5-18-98, 8-16-07, 5-8-13.