Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 481 - VIRGINIA RADIATION PROTECTION REGULATIONS › Part VI - Use Of Diagnostic X-Rays In The Healing Arts › Section 12VAC5-481-1621 - Radiographic equipment

Current through Register Vol. 40, No. 24, July 15, 2024
A. Control
				  and indication of technique factors.
1.
				  Visual indication. 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 that are set prior to the
				  exposure shall be indicated. On equipment having fixed technique factors, this
				  requirement may be met by permanent markings. Indication of technique factors
				  shall be visible from the operator's position except in the case of spot films
				  made by the fluoroscopist.
2.
				  Timers. Means shall be provided to terminate the exposure at a preset time
				  interval, a preset product of current and time, a preset number of pulses, or a
				  preset radiation exposure to the image receptor.
a. Except during serial radiography, the
				  operator shall be able to terminate the exposure at any time during an exposure
				  of greater than one-half second. Except during panoramic dental radiography,
				  termination of exposure shall cause automatic resetting of the timer to its
				  initial setting or to zero. It shall not be possible to make an exposure when
				  the timer is set to a zero or off position if either position is
				  provided.
b. During serial
				  radiography, the operator shall be able to terminate the x-ray exposure at any
				  time, but means may be provided to permit completion of any single exposure of
				  the series in process.
3. Automatic exposure controls. When an
				  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 equal to or greater than 51 kilovolts peak (kVp), the minimum
				  exposure time for field emission equipment rated for pulse operation shall be
				  equal to or less than a time interval equivalent to two pulses and the minimum
				  exposure time for all other equipment shall be equal to or less than 1/60
				  second or a time interval required to deliver five milliampere-seconds (mAs),
				  whichever is greater;
c. Either the
				  product of peak x-ray tube potential, current, and exposure time shall be
				  limited to not more than 60 kilowatt-seconds (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 51 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; and
d. A visible signal shall indicate when an
				  exposure has been terminated at the limits described in subdivision 3 c of this
				  subsection, and manual resetting shall be required before further automatically
				  timed exposures can be made.
4. Accuracy. Deviation of technique factors
				  from indicated values shall not exceed the limits given by the manufacturer. In
				  the absence of manufacturer's limits, the deviation shall not exceed 10% of the
				  indicated value for kVp and time.