Acoustic radiation force is a physical phenomenon resulting from the interaction of an acoustic wave

Acoustic wave

Acoustic waves are a type of longitudinal waves that propagate by means of adiabatic compression and decompression. Longitudinal waves are waves that have the same direction of vibration as their direction of travel. Important quantities for describing acoustic waves are sound pressure, particle...

 with an obstacle placed along its path. Generally, the force exerted on the obstacle is evaluated by integrating the acoustic radiation pressure

Acoustic radiation pressure

Acoustic radiation pressure is the apparent pressure difference between the average pressure at a surface moving with the sound displacements and the pressure that would have existed in the fluid of same mean density at rest...

 (due to the presence of the sonic wave) over its time-varying surface.

Medical Imaging Applications

Acoustic radiation force is currently being utilized in medical ultrasonic imaging to generate images based on the mechanical properties; Acoustic Radiation Force Impulse (ARFI) Imaging

Acoustic Radiation Force Impulse (ARFI) Imaging

Acoustic Radiation Force Impulse Imaging uses acoustic radiation force to generate images of the mechanical properties of soft tissue.-How it works:...

is one such modality. Other modalities include Shearwave Dispersion Ultrasound Vibrometry, Harmonic Motion Imaging (HMI), Supersonic Shear Imaging (SSI), and Spatially-Modulated Ultrasound Radiation Force (SMURF).