In addition to other requirements of this part, all diagnostic x-ray systems shall meet the following requirements:
    (1) Warning Label. The main control panel and all auxiliary control panels of the x-ray system shall bear the equivalent 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.””
    (2) Battery Charge Indicator. Visual means shall be provided on the control panel of battery-powered x-ray generators to indicate whether the battery is in a state of charge adequate for proper operation.
    (3) Leakage Radiation from the Diagnostic Source Assembly. The leakage radiation from the diagnostic source assembly measured at a distance of 1 meter in any direction from the source shall not exceed 100 milliroentgens (25.8 uC per kg) in 1 hour when the 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.
    (4) Radiation from Components Other than the Diagnostic Source Assembly. The radiation emitted by a component other than the diagnostic source assembly shall not exceed 2 milliroentgens (0.516 uC per kg) in 1 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.
    (5) Beam Quality.
    (a) Half-value Layer. The half-value layer (HVL) of the useful beam for a given x-ray tube potential shall not be less than the values shown below. If it is necessary to determine such half-value layer at an x-ray tube potential which is not listed below, linear interpolation or extrapolation may be made.
Design operating range (Kilovolts peak)
Measured potential (Kilovolts peak)
Half-value layer (Millimeters of aluminum)
Below 50
30
0.3

40
0.4

49
0.5
50 to 70
50
1.2

60
1.3

70
1.5
Above 70
71
2.1

80
2.3

90
2.5

100
2.7

110
3.0

120
3.2

130
3.5

140
3.8

150
4.1
    1. The above HVL criteria will be considered to have been met if it can be demonstrated that the aluminum equivalent of the total filtration in the primary beam is not less than that shown below:
Filtration Required vs. Operating Voltage
Operating Voltage (kVp)
Total Filtration (inherent plus added) (millimeters aluminum equivalent)
Below 50
0.5 millimeters
50-70
1.5 millimeters
Above 70
2.5 millimeters
    2. Beryllium window tubes shall have a minimum of 0.5 millimeters aluminum equivalent filtration permanently mounted in the useful beam.
    3. For capacitor energy storage equipment, compliance shall be determined with the maximum quantity of charge per exposure.
    4. The required minimum aluminum equivalent filtration shall include the filtration contributed by all materials which are always present between the focal spot of the tube and the patient.
    5. In addition to the requirements of paragraph (5)(a)1., above, all intraoral dental radiographic systems manufactured on and after December 1, 1980, shall have a minimum half-value layer not less than 1.5 millimeters aluminum equivalent filtration permanently installed in the useful beam.
    (b) Filtration Controls. For x-ray systems which have variable kVp and changeable filters, and which are used for low filtration techniques, a positive means shall be provided that will prevent an exposure unless the minimum required amount of filtration is in the useful beam for the selected kVp.
    (6) Aluminum Equivalent of Material between Patient and Image Receptor. The aluminum equivalent of each of the items listed below, which are used between the patient and image receptor, shall not exceed the indicated limits. This requirement is applicable to the front panel of cassette holders and film changers provided by the manufacturer for purposes of patient support or to prevent foreign object intrusions. It does not apply to such items as a screen and its associated mechanical support panel or grids.
Item
Maximum Aluminum Equivalent (millimeters)
Front panel of cassette holder (total of all)
1.0
Front panel of film changer (total of all)
1.0
Stationary tabletop
1.0
Moveable tabletop (including stationary subtop)
1.5
Cradle
2.0
    (7) Multiple Tube Heads. Where two or more radiographic tubes are controlled by one exposure switch, the tube or tubes which have been selected shall be clearly indicated prior to initiation of the exposure. This indication shall be both on the x-ray control panel and at or near the selected tube housing assembly.
    (8) 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 the tube housing movement is a designed function of the x-ray system.
    (9) Technique Indicators.
    (a) Each x-ray system shall be equipped with devices, such as labeled control settings or meters, correctly indicating the physical factors and modes of operation used for exposures. X-ray systems utilizing arbitrary number or letter designators for kVp, time and milliamperage shall be accompanied by a chart giving the value of physical factors for each arbitrary designator.
    (b) The technique factors to be used during an exposure shall be indicated before the exposure begins, except when automatic exposure controls are used, in which case the technique factors which are set prior to the exposure shall be indicated.
    (c) On equipment having fixed technique factors, the requirement in paragraph (9)(a), above, may be met by permanent markings. Indication of technique factors shall be visible from the operator’s position except in the case of fluoroscopy or spot films made by the fluoroscopist.
    (d) Reproducible technique factor indicators may be relabeled to meet the accuracy requirements of this part. Such relabeling shall be conspicuous and clearly legible and shall be utilized by the registrant in setting technique factors.
    (10) Accuracy of Technique Factors. Meters, labeled control settings, exposure time selectors and other physical factor indicators shall be accurate within the following tolerances:
    (a) Milliamperage (mA) – Radiographic ± 10%
    (b) Milliamperage (mA) – Fluoroscopic ± 0.2 mA
    (c) Kilovolt peak (kVp) ± 5 percent
    (d) Timer at settings:
    1. Greater than 10 seconds ± 1 second
    2. Ten seconds or less ± ten percent
    (11) Timer Reproducibility. When four timer tests are performed at the same timer settings, the average time period (T) shall be greater than or equal to 12 times the maximum time period (Tmax) less the minimum time period (Tmin). T shall be less than or equal to 0.5 seconds. Expressed mathematically, T ≥= 12 (Tmax – Tmin).
    (12) Exposure Reproducibility. The x-ray exposure produced by radiographic systems shall be reproducible to within the following criteria: When all technique factors are held constant and four or more exposures at the same technique factors are made, the value of the average exposure (E) shall be greater than or equal to 12 times the quantity of maximum exposure (Emax) minus the minimum exposure (Emin). Expressed mathematically, E ≥= 12 (Emax – Emin).
    (13) Exposure Linearity. The x-ray output produced by radiographic systems utilizing means other than automatic exposure controls shall be linear to within the following criteria:
    (a) When a choice of two or more current settings (mA) or current-time product settings (mAs) may be selected where X1 and X2 are the average mR per mAs values obtained from four exposures on each of two mA or mAs settings at a fixed tube potential (kVp) setting, within the range of 40 to 100 percent of the maximum tube rating, the average of four exposures (mR) for a given milliampere-second (mAs) product in mR per mAs shall not differ by more than:
    1. Five hundredths times the sum of any 2 consecutive mA or mAs averaged settings; expressed mathematically,
|X1 – X2 |≤= 0.05 (X1 + X2); and,
    2. One tenth times the sum of any other 2 mA or mAs averaged settings; expressed mathematically,
|X1 – X2 |≤= 0.10 (X1 – X2)
    (b) Equipment, which after calibration cannot be made to meet the requirements of paragraph (13)(a), above, may be relabeled to indicate the effective mA or mAs, 8providing that use of such relabeled stations will meet the requirements of paragraph (13)(a), above.
    (c) Equipment, which after calibration cannot be made to meet the requirements of paragraph (13)(a) or (b), above, shall not be used unless written approval is obtained from the Department. Approval shall not be granted when the linearity determination exceeds the federal standard for certified systems.
    (14) Automatic Exposure Controls. When automatic exposure control is provided:
    (a) Indication shall be made on the control panel when this mode of operation is selected.
    (b) When the x-ray tube potential is greater than or equal to 50 kVp, the minimum exposure time for field emission equipment rated for pulsed operation shall be less than or equal to a time interval equivalent to 2 pulses.
    (c) The minimum exposure time for all equipment other than that specified in paragraph (14)(b), above, shall be less than or equal to 1/60 second or a time interval required to deliver 5 mAs, whichever is greater.
    (d) 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 when the x-ray tube potential is less than 50 kVp, in which case the product of x-ray tube current and exposure time shall be limited to not more than 2,000 mAs per exposure.
    (e) A visible signal shall indicate when an exposure has been terminated at the limits described in paragraph (14)(d), above, and manual resetting shall be required before further automatically timed exposures can be made.
    (f) Exposure Linearity. When a choice of two or more tube current settings (mA) may be selected, the average of four consecutive exposures (E1) made at any one tube current setting minus the average of four consecutive exposures (En) made at any other tube current setting shall be less than or equal to 0.05 times the sum of the two averages. Expressed mathematically, |E1 – En |≤= 0.05 (E1 + En). Measuring compliance for the above shall be based on the following criteria:
    1. An attenuation block as described in subsection 64E-5.501(5), F.A.C., shall be in the useful beam.
    2. Exposure (mR) shall be measured on the exit side of the attenuation block.
    3. The tube potential (kVp) shall be maintained at a fixed setting within the range of 40 percent to 100 percent of the maximum tube rating.
    (15) Beam Limiting Devices.
    (a) Beam limiting devices capable of restricting the useful beam to the area of clinical interest shall be used during exposures.
    (b) Beam limiting devices shall provide a degree of attenuation not less than that required for the tube housing.
    (16) Remote Exposure Switches. Where an x-ray control is equipped with two or more remote exposure switches, each remote switch shall serve a single x-ray tube, and exposures with any tube shall be possible only by the remote switch with which that particular tube is associated.
    (17) Electrical Power Supply. The electrical power supply and service lines to x-ray systems shall be of sufficient capacity to permit operation without significant variation in voltage or machine output.
Rulemaking Authority 404.051, 404.151, 404.22 FS. Law Implemented 404.022, 404.051(1), (4), (6), 404.141, 404.22(1), (3) FS. History-New 7-17-85, Amended 4-4-89, Formerly 10D-91.604.