Investigation of a deformable mirror microwave imaging and therapy technique for breast cancer.

摘要

A novel deformable mirror microwave tomography technique for the nondestructive evaluation of non- or poorly conducting materials is investigated in this thesis. The proposed tomography technique utilizes a fixed transmitter antenna and a continuously deformable mirror with reflective coating to acquire multi-view measurements for permittivity reconstruction. The concept of using adaptive reflector antenna for medical imaging is introduced in this thesis with emphasis on breast cancer detection. Numerical simulations of the proposed imaging technique investigated using finite element boundary integral method and Tikhonov regularization technique for heterogeneous mathematical breast models indicate the feasibility of the new deformable mirror microwave tomography for breast imaging. Besides the computational study in the microwave regime, a simple experimental setup in the visible spectrum of electromagnetic radiation is also investigated to evaluate the merit in using mirror for multi-view measurements for material property inversion. One dimensional inversion results of material refractive index obtained using the proof-of-concept optical prototype employing single perfectly reflecting mirror emphasize the merit in using mirror for multi-view measurements and reinstates the feasibility of deformable mirror tomography technique.; In addition to its use for imaging, the system can be used for breast cancer therapy as well. A non-invasive thermal therapy technique employing dual deformable mirrors is investigated for the treatment of localized breast tumors. The proposed technique uses the deformable mirror to focus the incident electromagnetic radiation at the target tumor for thermal therapy. The feasibility of the proposed technique is evaluated via numerical simulations on two-dimensional breast phantoms. The electric field maintained by the deformable mirror is modeled and estimated using the boundary integral method. The EM energy deposited by the mirror is used in the bio-heat transfer equation to quantify the steady state temperature distribution inside the breast phantom. Computational studies on mathematical and MRI derived patient models indicate preferential EM energy deposition and temperature elevation inside the tumor with minimum collateral damage to the neighboring benign tissues. Extended simulation studies for non-invasive tumor ablation appear promising and indicate the prospects of a new applicator design.