Computational feasibility of deformable mirror microwave hyperthermia technique for localized breast tumors.

PURPOSE: Computational feasibility of a new non-invasive microwave hyperthermia technique that employs dual deformable mirror is investigated using simplified computational tools and anatomically realistic breast models. MATERIALS AND METHODS: The proposed technique employs two pairs of electromagnetic sources and continuously deformable mirrors to focus the electromagnetic radiation at the target site for hyperthermia. The mirror functions like a continuum of radiating elements that offer effective scan coverage inside the breast with efficient field focusing at the target location. The electric field focusing and temperature mapping in the two-dimensional numerical simulations are investigated using wave propagation and bio-heat transfer models respectively. The method of moments, a popular numerical simulation tool, is used to model the electric field maintained by the deformable mirrors for continuous wave excitation. The electromagnetic (EM) energy deposited by the mirrors is used in the steady state bio-heat transfer equation to quantify the temperature distribution inside two-dimensional anatomically realistic breast models. RESULTS: Feasibility of the proposed technique is evaluated using numerical breast models derived from magnetic resonance images of patients with variation in breast density, age and pathology. CONCLUSIONS: The computational study indicates preferential EM energy deposition and temperature elevation inside tumor tissue with minimum collateral damage to the neighboring normal tissues. Simulation results obtained for the magnetic resonance (MR) breast data appear promising and indicate the merit in pursuing the investigation using 3D computational models.