Ultrasonic Phase Tomography for Medical Applications
In an earlier paper, we presented the data to be expected from tomographic experiments on a phantom. The phantom contained elements with two different sound velocities. The numerical study made three different assumptions. The first being based on simple ray tracing, the second using straight paths between transmitter and receiver and the third using a diffraction solution using the Rytov approximation. None of these approaches models the situation exactly. The ray tracing neglects scattering and diffraction effects; the straight line path neglects refraction as well those previously mentioned. The diffraction solution assumes a large area coherent wavefront incident on the object being evaluated; a wavefront which it is not practically possible to produce.
This paper reports experimental measurements on a phantom nearly identical to that assumed in the numerical studies referred to earlier. The accuracy with which the various models fit the data is commented on and an empirical hybrid model which more accurately represents the situation is presented.
KeywordsTomographic Reconstruction Flight Data High Order Equation Digital Sampling Straight Line Path
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