In radiology, what does a higher fill factor indicate?

A higher fill factor refers to the percentage of a detector pixel that is sensitive to incoming radiation, essentially representing the area of the pixel that actively contributes to image formation. When the fill factor is higher, it means that a larger portion of the pixel area is devoted to detecting radiation rather than being occupied by non-sensitive components like circuitry.

This increased sensitivity allows for more efficient capture of the signal from the radiated photons, resulting in a better ability to detect lower levels of radiation. Therefore, a higher fill factor translates directly to more sensitive detector elements, making it the correct choice in the context of the question.

While other factors, such as radiation exposure, image resolution, and cost may be influenced by the design and technology used in imaging systems, they do not inherently define the function of a higher fill factor as clearly as the sensitivity of the detector elements.