A computational comparison of ultrasonically induced tissue heating between circular and rectangular transducer apertures

A method for calculating the temperature increase in a homogeneous tissue model is introduced. This method is not restricted to circular beams and therefore can be used to evaluate other geometries. By applying this model to exactly the same parameters as the heated disc model the following conclusions have been formed. The maximum temperature increase of a circular aperture focused transducer is the same for both the heated disc and the point-source temperature rise models for the specified parameters. However, the heated disc model does not accurately predict the temperature rise near the focal region. This is due to the modeling of the beam width near the focal region. The temperature rise for the square aperture (aspect ratio=1) occurs at the same axial feature distance as for the circular aperture, but the maximum temperature rise for the square aperture is less than the maximum temperature of the circular aperture.<
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