← Ultrasound subtopic / Sim: Frequency & Penetration
Frequency ↔ Penetration Explorer
Pick a transducer frequency and target depth. See how wavelength sets axial resolution and how attenuation limits useful penetration. High-frequency probes are sharper but don't reach deep; low-frequency probes reach deep but blur detail.
Teaching notes
Soft-tissue attenuation is ~0.5 dB/cm/MHz. Round-trip path is 2× depth, so total attenuation ≈ 0.5 × f(MHz) × 2 × depth(cm) dB. Wavelength λ = c/f = 1540/f (mm when f in MHz). Axial resolution is roughly half the spatial pulse length; with a typical 2–3 cycle pulse, axial resolution ≈ λ. Penetration becomes impractical once return signal attenuates by ~60–80 dB. Higher f = sharper but shallower; lower f = deeper but blurrier.