title: Theoretical temperature distributions produced by an annular phased array-type system in CT-based patient models.
abstract: Theoretical calculations for the specific absorption rate (SAR) and the resulting temperature distributions produced by an annular phased array (APA)-type system are made. The finite element numerical method is used in the formulation of both the electromagnetic (EM) and thermal boundary value problems. A number of detailed two-dimensional patient models based on CT-scan data from the pelvic, visceral, and thoracic regions are generated to simulate a variety of tumor locations and surrounding normal tissues. The SAR values from the EM solution are put into the bioheat transfer equation, and steady-state temperature distributions are calculated for a wide range of blood flow rates. Based on our theoretical modeling, the APA shows no preferential heating of superficial over deep-seated tumors. However, in most cases for all three regions of the human trunk only fair thermal profiles (therapeutic area near 60%) are obtained in tumors with little or no blood flow and poor temperature patterns (therapeutic area less than 50%) are found in tumors with moderate to high perfusion rates. These theoretical calculations should aid the clinician in the evaluation of the effectiveness of APA-type devices in heating tumors located in the trunk region.
mesh_terms: D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D008872:Microwaves / Q000627:therapeutic use; D008954:Models, Biological; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D013696:Temperature; D014057:Tomography, X-Ray Computed