Signature interactive · physics
Frequency vs Depth: the one tradeoff physics keeps testing
Higher frequency gives you sharper detail but less depth. It sounds simple - until it is a question on the SPI. Move the slider and watch detail and depth pull against each other.
Interactive
Move the transducer frequency
5.0 MHz
2 MHz (deep)15 MHz (shallow)
Approx. usable depth12 cmhow deep the beam still returns
Axial resolution0.46 mmlower = sharper detail
Curved array- general abdomen, deeper vascular
The shaded beam shows roughly how deep this frequency still returns useful echoes. Structures below the gold line are out of reach - you would drop to a lower frequency to see them.
Teaching estimate, not a spec sheet: depth and resolution are simplified to show the relationship (sound travels at ~1,540 m/s in soft tissue, so wavelength = 1.54 / frequency in mm). Real machines vary with focusing, power, patient, and harmonics.