Finite element analysis of temperature rise from an integrated 3-D intracardiac echo and ultrasound ablation transducer

A method for simulating the temperature rise due to acoustic heating from an ablation transducer is introduced. The size of lesions produced by this temperature rise is also modeled. First the intensity from the transducer is calculated using Field II. This intensity is scaled to a measured value and converted into acoustic heat generation. Finite element analysis is then used to find the temperature rise in tissue from this heat generation. Thermal dose is calculated and from that the size of any lesions may be predicted. We validate the model by comparing simulated results to experimental results from an ablation ring transducer. Temperatures were within 2°C of experiment after a 2 minute ablation. The simulation predicted a lesion size of 1.75 mm deep by 5.5 mm in diameter. The experimental average of four lesions was 1.75 mm deep by 4.6 mm in diameter. The model was then used to predict the temperatures and lesions created by an 86 element linear array transducer in various configurations.