Uploaded by Miracle Cambridge

X-ray Equipment Controls

University of Guyana
Health Sciences Faculty
Lecturer: Ms.Schimze Sagon
Presenter: Miracle Cambridge
• At the end of this presentation you should be able to:
• To define pneumonia
• To identify factors that predispose to pneumonia
• State how each of the factors can cause pneumonia
The control unit is the part of the x ray
system that allows the operator to
control technical factors.
Functions on the control unit
• on/ off
• Regulate incoming power
• Kvp selection
• Time selection
• mA selection
• There are three principle controls to a standard x ray system
• Current control (mA)
• The voltage control (kV)
• Timers
The console will have control for
• Focal spot (is the area of the anode surface which receives the beam of
electrons from the cathode)
• Line voltage compensation
The controls for the system are usually house in a panel.
Power supply
• Panel power on/off
1.Line compensation
• Line meter
• Primary side adjustment
Kvp selection
• Secondary side adjustment
variable turns ratio
Filament circuit power
mA selector
• Precision resistor
• Meter
Kvp selector
• Major / minor taps
• Meter (pre reading)
Time selector
• Circuit types
• Exposure switch
Line compensator: This is where the voltage from the wall plug-in is measured and
then stabilized to 220 Volts for the x-ray circuit.
Autotransformer: Has a single winding and sends voltage to the filament and high
voltage circuit
A. Selects the major or minor kvp and steps the voltage up to
kvp meter: measures the electrical potential of the x-ray tube.
Exposure switch: used to complete the x-ray exposure. It regulates the length of the
filament circuit: where we have the ammeter, or the mA selector, which selects the
tube current to heat the filament.
• The number of electron emitted by the filament is determined by the
temperature of the filament.
• The filament operate at currents between 3 and 6 A
• Tube current is controlled through a separate circuit
• .The voltage is provided by the taps of the autotransformer
• The voltage is then delivered to the filament transformer
• The selection of the small or large filament is connected to the mA
Setting the desired kvp will determine the voltage applied
to the step up transformer in the high voltage section of
the machine
Kvp determine the quality of the x ray beam.
• Timers are used in the system so that radiographer starts the exposure and the timers stops it.
• The timer circuit is separate from the other main circuit of the x ray circuit of the x ray system.
Type of Timers
• Mechanical timers
• Electronic timers
Selecting time: control time it takes to charge the capacitor
Activating exposure also begin storage of charge in the capacitor
• MAs timers :a special type of timer that accurately control tube current and exposure time
• The product of mA and time(mAs) determine the number of x ray photon emitted and the density
on the film
• Monitors the product of mA and terminates the exposure when the desired mAs has been attained.
• An electric meter, or energy meter, is a device that measures
the amount of electric energy consumed by x-ray console .
• The kvp meter accelerating voltage is measured .
• The mAs meter which measures the current going to the xray tube.
• The pre-reading kvp meter: indicates anticipated kvp.
• Exposure switch: it initates time and terminates the exposure.
• Line monitor : supplies precise voltage to filament circuit and
high voltage transformer.
• Quantity refers to the number of x ray photon in the beam.
• As the number of photon increase the beam intensity increases
• Quantity is affected by changes in mA( tube current) and
Changes in Kvp.
• Changes in mA Tube current is the rate of electron flow from
filament to Target
• As the tube current increase the number of incoming electron
striking target increases
• Quality refers to the overall energy of the beam
• Quality is directly affected changes in kvp (maximum voltage
applied across an x ray tube)
• The increase in kvp increase the speed with which incoming
electron strike the target
• Hence as the kvp increase more higher energy photon are
included in the beam.
• Current mA
• Voltage kvp
• time
• Increase in quantity ; no
changes in quality
• An increase in quality and
• Altering the time setting
influences the quantity of
x-rays and image density
• Conventional imaging control units was manually worked Parts
of the control unit on either on or behind the image receptor.
• Digital image the control unit is located in the control room and
all the parts was place together and there is automatic and
manual input.
Stewart C. Bushong ScD FACR FACMP-Radiologic Science for Technologists_ Physics,
Biology, and Protection, 10e-Mosby (2012).
• Diagnostic Radiology Physics
• Bushong, Stewart C. Radiologic Science for Technologists: Physics, Biology, and
Protection. Mosby, 2017.
• Carlton, Richard R., and Arlene McKenna Adler. Principles of Radiographic Imaging: An
Art and a Science. Fifth edition. Clifton Park, New York: Delmar/Cengage Learning, 2013.