Acoustic microscopy uses high-frequency ultrasound to image structures non-invasively. Sound is focused and directed towards an object, by which it may be scattered, reflected or transmitted. By measuring the reflected and back-scattered sound it is possible to determine the structure of the object. By scanning across the surface of an object the point at which the focus lies is moved, creating what is known as a Scanning Acoustic Microscope (SAM), with which it is possible to construct 3D images.
The set-up in the BUBL laboratories (shown below) uses an operating frequency of 75MHz, which can provide axial resolution of up to 20µm, and is currently used to image particles that have been injected into tissue using needle-free injection. Work is also being carried out to develop a technique which may be used to measure the rate of dissolution of drug particles, following injection, in real-time. Due to the broadband nature of the transducer which is used, many exciting spectral analysis techniques may be developed, making the SAM an extremely versatile tool. Such spectral techniques are currently used to measure the size of particles in tissue-mimicking materials.
For further information regarding the Scanning Acoustic Microscope and its capabilities, please contact Jamie Condliffe.
J Condliffe, J Collin, F Carter, G Costigan and C.-C. Coussios, ‘An Acoustic Microscopy Technique to Assess Particle Distribution Following Needle-Free Injection’, Proc. Institute of Acoustics 28(1) (2006).