What is the most significant effect of reducing kVp on a fluoroscopic image?

The most significant effect of reducing the kilovolt peak (kVp) on a fluoroscopic image is increased contrast. When kVp is lowered, the energy of the x-ray photons produced also decreases. This results in a greater difference in the attenuation of the x-rays by different tissues, leading to higher contrast between structures in the image.

Lowering kVp results in a higher photoelectric effect relative to Compton scattering, which is beneficial for visualizing soft tissues where contrast is needed. While decreased image brightness, increased exposure time, and decreased patient dose can be consequences of altering kVp, the predominant and most direct impact of a reduced kVp is the enhancement of image contrast. This is crucial in diagnostic imaging as it allows for better differentiation of anatomical structures, enhancing the overall quality of the fluoroscopic examination.