CT High Voltage Generator

High-frequency generators are currently used in CT. They

are small enough so that they can be located within the

gantry. Highly stable three-phase generators have also been

used, but because these are stand-alone units located near

the gantry and require cables, they have become obsolete.

Generators produce high voltage and transmit it to

the x-ray tube. The power capacity of the generator is

listed in kilowatts (kW). The power capacity of the generator

determines the range of exposure techniques (i.e.,

kV and mA settings) available on a particular system. CT

generators produce high kV (generally 120–140 kV) to

increase the intensity of the beam, which will increase the

penetrating ability of the x-ray beam and thereby reduce

patient dose. In addition, a higher kV setting will help to

reduce the heat load on the x-ray tube by allowing a lower

mA setting. Reducing the heat load on the x-ray tube will

extend the life of the tube.