Which parameter does NOT influence the spatial resolution of a digital radiograph?

• A. Matrix Size
• B. DEL Size
• C. DEL Pitch
• D. Bit Depth

Answer: (D)

Spatial resolution depends on how finely the image is sampled and how small the detector elements are. When the detector element size is smaller, each pixel covers a smaller area, so more detail can be captured and nearby structures can be distinguished. Increasing the matrix size while keeping the field of view constant also reduces pixel size, improving sampling density and sharpness. The spacing between detector elements, or the DEL pitch, affects how many samples fit into a given area—a larger pitch means fewer samples across the same width, which lowers resolution.

Bit depth does not change how finely the image is sampled; it determines how many gray shades the image can display, influencing contrast resolution rather than spatial resolution. So the parameter that does not influence spatial resolution is bit depth.