2-D Axisymmetric Finite Difference Modeling of Thermistor Probe Heating on the Kidney

Developing a means of determining whether or not there is adequate perfusion in a newly transplanted kidney is the impetus for this study. The concept analyzed is that of a self-heating thermistor probe located between the kidney and the adjacent body tissue, inserted during the transplant procedure. When appropriate perfusion is present in the kidney, more heat will be dissipated in the organ tissue than when perfusion is insufficient for transplant success. If the heat dissipation for a given probe temperature above the bulk tissue is monitored, this might be able to be used as an indicator of procedural success or failure. To assess the sensitivity of this approach a numerical model has been developed and is reported here. An axisymmetric two-dimensional finite-difference formulation is used. Results are shown using typical values of properties for perfused and non-perfused tissue. The sensitivity of the approach to these properties indicates the type of accuracy that will be required in the clinical application of the technique