Ultrasound technique for tissue differentiation
Cheatham, John B., Jr.
Master of Science
Pressure sores are a serious medical problem, which cause a great deal of economic and physical damage. The old method of skin color identification is not quantitative and is usually unreliable. Among various methods which are being tried for early identification of pressure sores, ultrasonic technique is one. A method has been developed which helps to calculate the stiffness of the tissue under the skin at various depths. This method consists of a perturbator which vibrates on the surface of the skin with a known amplitude and frequency. The wave generated on the surface behaves as an exponentially decaying sinusoidal wave with respect to time and downward distance for a constant stiffness of the medium. With the help of an ultrasonic transducer embedded on the perturbator head, displacement can be calculated at each depth for various times. Using computer software, these displacements are noted for various times to find out the amplitude for each depth which is then plotted on the computer screen. According to the changes in slope of the curve, different tissue regions are identified and their moduli are compared. A computer simulation to show the expected amplitude-depth plot for a possible pressure sore region is done.
Biomedical engineering; Mechanical engineering