Abstract
The use of an interrogating ultrasound beam for noninvasive measurement of temperature has been investigated from many perspectives. Our group is looking at how the backscattered energy from individual scatterers changes with temperature. By measuring the backscattered energy from a single ultrasound beam (A-mode) in a tissue sample while changing the tissue temperature we have gathered data from a minimum of 5 sites in several different tissue samples. We have performed experiments on bovine liver and turkey breast. Changes in backscattered energy appear to be consistent between the different types of tissue. Typically we have seen a change of between 5 and 15 dB in backscattered energy over the temperature range of 37 – 50oC. The energy may either increase or decrease with temperature depending on the type of scatterer that is being followed. To follow the behavior of the signal from individual scatterers we have segmented signals by hand. To automate the process we have segmented with matched filters and with arbitrary segment intervals. The performance of both methods was comparable to hand segmentation. The success of these automatic methods suggests that changes in backscattered signals with temperature can be tracked in real time over a variety of tissue types.
Support in part by NIH R21 CA90531