Frank Winterroth

By Frank Winterroth

Medical ultrasound is a diagnostic imaging technique used for visualizing subcutaneous body structures. The frequencies used in conventional diagnostic ultrasound are typically 2–10 MHz. For scanning acoustic microscopy (SAM), the frequencies applied to image cells and tissues are >50 MHz. Increasing the frequency increases spatial resolution, but reduces the depth that can be imaged. The advantages of using SAM over conventional light and electron microscopes include imaging specimens without requiring any preparations which may kill or alter them; this provides a more accurate representation of them. SAM’s main components are similar to those found on typical light microscopes, but the lens is often replaced by a confocal transducer. The ultrasound signal encountering the specimen generally has three results: scatter, transmission, or reflection; these signals are then merged to form the image as either a B-Scan or C-Scan. The acoustic parameters determining the image quality are absorption and scattering. SAM can objectively quantify the surface characteristics of the specimen being scanned and can also study the elastic properties of cells and tissues to discern differences between healthy and affected conditions. SAM has the potential as a major instrument of detection and analyses in biomedical research and clinical studies.

Part of the book: Microscopy and Analysis