Final answer:
In a fixed kVp system, a higher kilovoltage results in increased penetration of x-rays leading to lower contrast in the image, but it can also result in a lower radiation dose to the patient due to potentially reduced exposure time.
Step-by-step explanation:
In a fixed kilovolt peak (kVp) system, when the kilovoltage is constant, the dose refers to the amount of x-ray energy absorbed by the tissue. As the energy increases with higher kVp settings, the X-rays penetrate the materials more effectively. This results in fewer X-rays being absorbed by denser material, such as bone, leading to a reduced contrast in the X-ray image. The denser the material, the darker the shadow on the x-ray. On the other hand, a higher kVp setting will increase the penetration of x-ray photons, potentially lowering the image contrast as differences between tissues become less pronounced.
Modern practices in radiography aim to minimize the dose to the patient by implementing protective measures such as lead aprons and using fast films that reduce the time needed to obtain images. While a higher kVp can reduce contrast, it also has the potential to lower the dose as it may allow for a shorter exposure time. An effective dose is calculated by considering the energy absorbed and adjusting for the sensitivity of different tissues to radiation.