Towards Optimization of Open Ended Contact Probes for Breast Cancer Diagnosis

Development of new modalities for breast cancer detection have been a research interest due to the drawbacks of existing diagnostic technologies such as imaging with ionizing waves. In particular, microwave imaging has been investigated in the literature as a new modality for breast cancer detection. Microwave imaging is a promising technique due to the high dielectric contrast between benign and malignant lesions. With this motivation, the dielectric properties of the benign and malignant breast tissues were measured and such measurements have been performed with the open ended contact probes. The open ended contact probe technique widely used in laboratory environment to characterize the dielectric properties of materials with high permittivity and conductivity due to the advantages such as broad band measurement capabilities and limited sample size requirements. The utilization of the open ended contact probe technique as a breast cancer diagnostic technology have been previously envisioned in the literature. One such application is integration of these probes to biopsy guides to diagnose whether the breast lesions are benign or malignant. However, due to the poor measurement accuracy and repeatability the utilization of the technique as a diagnostic technology was not realized. The drawbacks of the technology mostly stem from the mathematical approaches and the deviations from the initial calibration conditions. In this work, to increase the accuracy of the open ended contact probe measurement technique, the probe structure is redesigned by removing the microwave connections and integrating the probe with the RF cable. Probe simulations are performed with Computer Simulation Technology (CST). The probe is tested with both known materials and more complex environments such as methanol and phantom experiments. Oil-in-gelatine dispersion phantom materials are composed and measured with the designed probe. Probes with small aperture diameters were also evaluated to investigate the potential practical utilization of such probes. Dielectric properties are calculated with in-house dielectric property retrieval algorithm. A good agreement is obtained with the reference data.