Breast cancer is a significant health problem which results in roughly 44,000 deaths annually in the United States. Early detection and treatment remain the best method for improving long-term survival and overall quality of life. While X-ray mammography has been shown to be effective in breast cancer screening, it does have limitations in terms of sensitivity and specificity especially for certain categories such as radiographically dense breasts. We are currently developing a microwave tomographic breast imaging system that can exploit the significant electrical property contrast between normal and malignant breast tissue. Early results have been promising in terms of detecting cancers, but have also underscored the fact that the breast is a complex organ with widely varying internal structures which significantly impact the overall electrical property distribution. Our early clinical prototype has provided us with a unique test bed to explore a variety of tools at our disposal including broadband analysis and a range of coupling medium properties as we prepare to expand to fully 3D operation. In the current clinical system, the patient lies prone with one breast pendant through an aperture in the illumination tank cover into a liquid bath of glycerin and water. The monopole antennas protrude into the tank through hydraulic seals in the tank base and surround the breast. They are mounted to an antenna array plate whose vertical height is adjusted by a computer-controlled linear actuator for multiple plane interrogation. Given that the antennas do not compress the breast and the soothing texture of the glycerine water bath, the initial patient feedback in terms of comfort has been extremely positive. The reconstruction algorithm is a Gauss-Newton iterative scheme, which utilizes a 2D finite element (FE) based approach for the forward computation of the electric fields. We have found that by using our log- magnitude /phase form (LMPF) algorithm the robustness of the algorithm has significantly improved when imaging large, high-contrast objects (4). This largely appears to be a feature of the fact that information is
[1]
W. Joines,et al.
The measured electrical properties of normal and malignant human tissues from 50 to 900 MHz.
,
1994,
Medical physics.
[2]
S. S. Chaudhary,et al.
Dielectric properties of normal & malignant human breast tissues at radiowave & microwave frequencies.
,
1984,
Indian journal of biochemistry & biophysics.
[3]
Alexander Hartov,et al.
Electromagnetic breast imaging: average tissue property values in women with negative clinical findings.
,
2004,
Radiology.
[4]
B. Pogue,et al.
Microwave image reconstruction utilizing log-magnitude and unwrapped phase to improve high-contrast object recovery
,
2001,
IEEE Transactions on Medical Imaging.