<title>Microwave Thermoelastic Tissue Imaging</title>

Abstract

A microwave-induced thermoelastic tissue imaging system is suggested as a new and promising imaging modality. It appears to possess some unique features that may allow it to become as useful as these other methods and to permit non-invasive tissue imaging of tissue characteristics which are not identifiable by other techniques. It uses nonionizing radiation and relies on a beam of impinging microwave to launch an acoustic wavefront into tissue. There is a direct relation between the pattern of absorbed microwave pulses and the induced thermoelastic pressure waves in biological tissues. Moreover, regions of differing permittivity would exhibit differential absorption. This thermoelastic wave of pressure would propagate through the tissue and be detected by a two-dimensional array of piezoelectric transducers positioned on the body surface to give an image of the intervening tissue structure. Signals from the outputs of this transducer array are then amplified and band-limited at a signal conditioning stage. A computer-controlled data acquisition system samples and converts them to digital form for further processing. A hybrid parralel/serial design of dividing the array into segments and collecting data from each segment sequentially is used. Image processing algorithms are applied to digitized pictures for enhancing the images. The processed two-dimensional image is displayed on a color monitor. An example showing the image of a human hand model illustrates the potential usefulness of microwave-induced thermoelastic tissue imaging.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.