EFFECT OF INTERSEED SPACING, TISSUE PERFUSION, THERMOSEED TEMPERATURES AND CATHETERS IN FERROMAGNETIC HYPERTHERMIA - RESULTS FROM SIMULATIONS USING FINITE-ELEMENT MODELS OF THERMOSEEDS AND CATHETERS

Finite element heat-transfer models of ferromagnetic thermoseeds and c atheters are developed for simulating ferromagnetic hyperthermia. Thes e models are implemented into a general purpose, finite element comput er program to solve the bioheat transfer equation. The seed and cathet er models are unique in that they have fewer modeling constraints than other previously developed thermal models. Simulations are conducted with a 4 x 4 array of seeds in a multicompartment tissue model. The he at transfer model predicts that fractions of tumor greater than 43 deg rees C are between 8 and 40% Lower when seed temperatures depend on po wer versus models which assume a constant seed temperature. Fractions of tumor greater than 42 degrees C, in simulations using seed and cath eter models, are between 3.3 and 25% lower than in simulations with ba re seeds. It is demonstrated that an array of seeds with Curie points of 62.6 degrees C heats the tumor very well over nearly all blood perf usion cases studied. In summary, results herein suggest that thermal m odels simulating ferromagnetic hyperthermia should consider the power- temperature dependence of seeds and include explicit models of cathete rs.