Which of the following factors influence the grayscale of a digital radiograph?

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

Answer: (D)

Grayscale is defined by how many brightness levels the image can represent, and that comes from the bit depth (bits per pixel). More bits per pixel provide more distinct gray values, giving finer contrast resolution and smoother transitions between light and dark areas. This is why increasing bit depth reduces banding and improves the ability to discern subtle differences in tissue. The display windowing can map those available gray values to the monitor, but you can’t display more shades than the bit depth allows. The other factors change spatial characteristics: matrix size affects how many pixels sample the image (sharpness), and detector element size or pitch influences spatial resolution and noise. They don’t change how many gray levels the image can contain.