What effect does increasing ultrasound frequency have on depth of penetration?

• A. Increases depth
• B. No effect
• C. Depends on tissue type
• D. Decreases depth

Answer: (D)

Increasing the frequency makes the ultrasound wave lose energy more quickly as it travels through tissue. Attenuation from absorption and scattering grows with frequency, so the beam weakens sooner and cannot reach as deep. That’s why higher-frequency probes provide better detail but shallower penetration, while lower-frequency waves reach deeper but with less resolution. So the depth of penetration decreases as frequency increases. Tissue type can affect exact depth, but the general trend remains: higher frequency means shallower penetration.