What effect does changing from a 60 kVp to a 70 kVp machine have on exposure time?

When the kilovolt peak (kVp) is increased from 60 to 70, the overall penetration power of the X-rays produced is enhanced, which significantly affects the exposure time required for imaging. Increasing kVp typically results in a higher energy beam, allowing the X-rays to more effectively pass through the tissues being imaged. As a result, the required exposure time is often reduced, leading to a decrease in the duration needed to obtain a diagnostic image.

In this scenario, the reduction in exposure time could be substantial, sometimes approximating half the original time. This is because the increase in energy not only improves the quality of the image—providing better contrast and resolution—but also minimizes patient exposure to radiation by achieving adequate imaging at a shorter duration. Thus, the correct answer reflects this relationship, showcasing the principle that higher kVp allows more efficient imaging.