Bioimpedence analysis techniques for malignant tissue identification

The use of bioimpedance techniques for malignancy identification is considered novel, with challenges existing that need to be overcome. In this thesis, such bioimpedance approaches have been developed for identifying malignancies through a systematic study, ranging from the investigation of the technical challenges affecting an imaging based breast cancer detection system, to the study of electrical properties of tissue and cells. Hence, this work provides proof-of-concept for cancer diagnosis based on the electrical signatures that differentiate malignancies from normal tissue, utilising bioimpedance analysis techniques. Further, this work will contribute to the understanding of correlations between electrical properties and biological functions, which will help to explore bioimpedance techniques for wider medical and bioscience applications. Furthermore, this research will also be conducive to investigations of novel devices for cancer diagnosis in clinic. The Ph.D work was carried out in two threads. In the first thread, technical challenges of using Electrical Impedance Mammography (EIM), an imaging modality developed based on bioimpedance technique for breast cancer diagnosis, were studied on 1) effectively reducing measurement errors from electrode contact interfaces, and 2) validating systems by using novel simulation phantoms. In the second thread, bioimpedance spectroscopy (BIS) of tissues and cells was investigated to 1) reveal their electrical properties, 2) identify malignant changes, and 3) establish correlations of electrical properties with biological function changes. By carrying studies in these two threads, bioimpedance was fully investigated for its applications on cancer detection and diagnosis. This work has made significant contributions to the field of study. It comprises the first systematic study on bioimpedance for cancer identification at the tissue and cellular levels. This work has also been pioneering in linking the electrical properties of malignant tissues and cells to the relevant biological changes brought on by the aforementioned malignancies.