The smallest resolvable detector unit is called which?

• A. Detector Size
• B. Detector Element
• C. TFT Size
• D. Dynamic Range

Answer: (B)

In digital radiography, spatial sampling is determined by the detector elements. The smallest resolvable detector unit is a detector element (often called a DEL). Each detector element is the individual sensing site that converts x-rays into an electrical signal and corresponds to a single pixel in the final image. The size and pitch of these elements set the native spatial resolution—the smaller the detector elements, the finer the potential detail that can be displayed. Other terms like detector size describe the overall panel dimensions, not the smallest resolvable unit. The size of the thin-film transistor (TFT) relates to readout electronics, and dynamic range concerns the range of gray values the system can record, not the sampling of the image. So the detector element is the unit that defines the finest resolvable detail.