Final answer:
In a dynamic flat panel detector fluoroscopy system, the image intensifier is the component that is replaced, leading to direct conversion of X-rays into electronic signals for image formation and improved quality.
Step-by-step explanation:
In a dynamic flat panel detector fluoroscopy system, the component that is replaced as compared to a conventional fluoroscopy system is the image intensifier. Traditional fluoroscopy systems rely on an image intensifier that converts X-rays into visible light, which is then captured by a TV camera and displayed on a monitor. Flat panel detectors, however, use digital detector technology to convert X-rays directly into an electronic signal that produces the image, rendering the need for an image intensifier obsolete. This advancement leads to improved image quality and efficiency in capturing photons.