Final answer:
In a variable kVp system, the radiographer sets the potential difference between the electron source and the metallic target in the x-ray tube. The kVp determines the energy of the x-ray photons produced, allowing for adjustment of penetration for different imaging needs.
Step-by-step explanation:
In a variable kVp system, the radiographer sets the potential difference (kVp) between the electron source and the metallic target in the x-ray tube.
The kVp determines the energy of the x-ray photons produced by the tube. Higher kVp values result in higher energy photons, which can penetrate denser materials. This allows the radiographer to adjust the level of penetration for different imaging needs, such as thicker or denser body parts.
For example, if a radiographer is imaging a chest, they may set a lower kVp value (e.g. 50.0 kV) since the chest is not as dense as other body parts. However, if they need to image a broken leg in a cast, they may set a higher kVp value (e.g. 100 kV) to penetrate through the denser material of the cast.