Dynamic range in ultrasound systems is controlled by which control?

• A. The transducer's center frequency
• B. The receiver's dynamic range setting
• C. The imaging depth
• D. Display brightness

Answer: (B)

Dynamic range describes how many grayscale shades the display can show, mapping a wide spread of echo amplitudes into a manageable set of gray levels. The control that sets this is the receiver’s dynamic range setting, which determines how the scan converter compresses echoes into display gray levels. A higher dynamic range lets more subtle differences in tissue be visible (more gray shades), while a lower dynamic range increases contrast but reduces detail in the mid-to-low amplitude echoes. The other factors—transducer center frequency, imaging depth, and display brightness—affect penetration, timing, or perceived brightness, but do not set the number of grayscale levels the image can display.