Inverse tumor temperature reconstruction of human hyperthermia treatments

In this research a computer package using patient magnetic resonance (MR) data was created and tested when used to predict hyperthermia treatment temperatures. The package achieves this goal by the following steps it: (1) creates a Finite Element (FE) mesh (which includes regions of bone, tumor, muscle, and vessels with blood flow) of the patient anatomy from pretreatment MR Angiography and T2 anatomical images; (2) applies a distribution of perfusion values to the elements of the FE mesh; (3) applies the thermophysical parameters to the appropriate elements and nodes of the FE mesh, and; (4) estimates the unknown model parameters and temperatures using an inverse code to match the FE model temperatures with the MR measured temperatures.; The hyperthermia treatments were conducted at Duke University, and consisted of heating patients' leg tumors with microwave antennae in the MR. Three studies were performed using the package and the hyperthermia treatment data supplied by Duke University. The first study used Patient Small's pretreatment data to debug and evaluate the performance of the computer package. The results showed that the computer package created and solved a FE model as well as solved the inverse problem. The second study used the computer package and Patient Medium's treatment data to investigate the applicability of using MR measured tissue uptake in order to model the distribution of perfusion. This study provided an explorative rather than definitive investigation of the ability of the computer package to accurately estimate hyperthermia temperatures with the supplied treatment data. The results showed that using the MR measured tissue uptake to model perfusion resulted in a scattered distribution of temperature which represents the MR measured temperatures. The third study used the computer package and the data from all three patients to quantify the sensitivity of changes in model temperatures with respect to changes in unknown model parameters. The results of this study showed that larger anatomical regions or regions with numerous MR measured tissue uptake located near the center of the leg had a greater influence on temperature than small anatomical regions located near the skin.