- Control Panel
kV, mA and Timer(s) selectors kVp(KiloVoltagePeak)
- The energy (the penetrating power) of the x-ray beam is controlled by the voltage adjustment.
- It is labelled in keV (thousand electron volts) and sometimes the level is referred to as kVp (kilovoltage potential).
- The higher the voltage setting, the more energetic will be the beam of x-ray.
- It plays major part in affecting contrast of image.
mA (MiliAmperage)
- The second control of the output of the x-ray tube is called the mA (milliamperage) control.
- This control determines how much current is allowed to flow through the filament which is the cathode side of the tube.
- The effect of the mA circuit is quite linear.
- It is more concerned in density aspect of the image.
Timer (s)
- Control length of time machine produces x rays
- This is usually denoted as an "S" (exposure time in seconds) and is combined with the mA control.
- e.g using 10 milliampere seconds you could use a 10 mA current with a 1.0 second exposure or a 20 mA current for a 0.5 second exposure or any combination of the two which would result in the number 10.
- Both of these factors and their combination affect the film in a linear way.