Perfusion corrections for ultrasonic heating in nonperfused media.
The linear bio-heat transfer equation proposed by Pennes is widely used to predict temperature rise in perfused media. In this article, a mathematical relationship between the predicted temperature increase under perfused and nonperfused conditions is derived based on an analysis of the Pennes equation. The perfused temperature at time t and position r, Tperf(r,t) can be calculated from the unperfused temperature history Tunperf(r,t) and the time constant for perfusion, tau: [formula: see text] When the full nonperfused temperature history is not available, a simpler approximate method of estimating the perfused temperature is also suggested, requiring only a knowledge of the time constant for perfusion. Results are given showing the effects of perfusion after different exposure times for a range of beamwidths and perfusion time constants.
Shaw
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Centre for Ionising Radiation and Acoustics, National Physical Laboratory, Teddington, Middlesex, UK.
Preston
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RC
Bacon
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DR
D000465:Algorithms; D004058:Diffusion; D005544:Forecasting; D006358:Hot Temperature; D018499:Linear Energy Transfer; D008962:Models, Theoretical; D013696:Temperature; D013997:Time Factors; D014463:Ultrasonography / Q000009:adverse effects*