Infographics / Ultrasound Physics

Attenuation, frequency dependence and penetration

A straight line rising from the origin plots attenuation per centimetre against transducer frequency, with slope of about 0.5 decibels per centimetre per megahertz in soft tissue. Two marked points show that doubling the frequency from 5 to 10 megahertz doubles the loss from 2.5 to 5 decibels per centimetre. Two opposing arrows beneath the axis indicate that lower frequency gives greater penetration depth while higher frequency gives finer axial resolution.

Ultrasound attenuation versus frequency and the penetration–resolution trade-off A straight line rising from the origin plots attenuation per centimetre against transducer frequency, with slope of about 0.5 decibels per centimetre per megahertz in soft tissue. Two marked points show that doubling the frequency from 5 to 10 megahertz doubles the loss from 2.5 to 5 decibels per centimetre. Two opposing arrows beneath the axis indicate that lower frequency gives greater penetration depth while higher frequency gives finer axial resolution. Attenuation rises with frequency: the penetration–resolution trade-off 2.5 5.0 7.5 5 10 15 transducer frequency (MHz) attenuation per cm (dB/cm) α ≈ 0.5 dB/cm/MHz (soft tissue) doubling the frequency doubles the loss per cm greater penetration depth finer axial resolution Higher frequency means more attenuation and shallower penetration, but finer axial resolution.
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