Assessment of the temperature distribution during hyperthermia treatment by isolated extremity perfusion

A finite-element model of the human leg is developed for the assessment of temperature distribution during hyperthermia treatment by isolated extremity perfusion with a heart-lung-machine. The simulation comprises the true geometry, adequate perfusion models for the different parts of the extremity circulation in normal and tumour tissue, and the numerical procedure for the solution of the partial differential heat balance equation used. The simulation is validated using both experimental physiological and clinical data, and predicts temperature distributions and courses for various modifications of the hyperthermia procedure. It is concluded that the homogeneous temperature required in combination with chemotherapy can be achieved by isolated extremity perfusion, if a good thermal insulation is applied. If temperatures >42 degrees C are required, an additional external heat source (microwaves or ultrasound) is necessary. Although these sources may produce high absorption rates, combination with extremity perfusion is useful in reducing higher temperature gradients and the danger of locally lower temperatures.