Further Exploration of EIT in Cancer Detection

Electrical Impedance Tomography (EIT) is a non-invasive detection technique which is able to distinguish between cancerous and non-cancerous cells. This thesis addresses some of the issues associated with EIT system design. Initially a study was completed to source an improved voltage-to-current convertor for the current Leicester system. Two circuits were designed and simulated using PSpice software and compared for their responses and to ascertain the capacity for improvement through component advancement. Simulated results indicated that the Improved Howland circuit was superior for the specific needs of the Leicester group. Secondly, following a review of current techniques for improving the high frequency response of EIT systems, a theory for using a time response method as a solution was developed. The new method was directly compared to the existing frequency technique by analysing electronic phantom and organic samples with both systems. Finally an investigation was completed in the area of micro EIT which aimed to detect cancerous islets within mouse pancreata with aims to distinguish normal and cancerous cells, and, ultimately, to detect cancerous single cell “escapers”. Three methods were described. The initial technique tested in-vitro pancreata and results from this suggested that the approach was a viable method for indentifying the affected tissue; therefore additional methods were designed to test individual extracted islets. In summary, the thesis provides an improved alternative V-to-I convertor for the Leicester group’s system, which has been adopted in experiments. The time response method investigation showed that it may provide a viable method that could, with further development and analytical refinement, improve the effectiveness of cell modelling in several interesting ways. Further investigation is suggested. The positive results provided by the whole pancreas testing are a convincing reason for further work to be conducted in this area, in particular work to enhance the diagnostic analysis of pancreata.