Final answer:
Option 4: Direct conversion digital imaging systems convert remnant x-ray photons to an electrical signal in a single step, without relying on intermediate light photons.
Step-by-step explanation:
The type of digital imaging system that uses a single process to convert remnant x-ray photons to an electrical signal is known as direct conversion. This method is distinct from indirect conversion systems, where the process involves two steps: first converting the x-ray photons to light photons and then converting the light photons to an electrical signal. In direct conversion digital imaging, a photoconductor absorbs x-ray photons and directly converts them into an electrical charge, which is then used to form an image.
A digital imaging system that uses a single process to convert remnant x-ray photons to an electrical signal is direct conversion. In direct conversion, x-ray photons are absorbed by a solid-state detector material (such as amorphous selenium or cadmium telluride) which directly converts them into electrical charges. The electrical charges are then readout and processed to create the digital image.