A bioimpedance sensing system for in-vivo cancer tissue identification: Design and preliminary evaluation.

Bioimpedance evaluation can provide useful information for biological tissue characterization and potentially allows the identification of pathological areas within a tissue in-vivo. In this study a new needle-based bioimpedance sensing system was designed and developed to provide such capability considering intra-operative detection of cancerous tissue in the larynx as the primary specific application. The system is small, low-power, fully embedded in a printed circuit board and based on a disposable concentric electrode needle. These characteristics make it appropriate for the envisioned clinical use. In addition, the device operates in real-time and offers functionalities allowing the tuning of its properties to maximize its sensing capabilities for different applications. This includes the possibility to perform bioimpedance measurements using a sweep of excitation frequencies or a single frequency. Here, the first functionality was used to evaluate the instrument's tissue discrimination performance at different frequencies and consequently identify the best frequency for such task. The second functionality was used to evaluate the performance of the system by obtaining repeated measurements on different locations of specific biological tissues. This was done using six different ex-vivo animal tissues and an ex-vivo porcine larynx. The bioimpedance measurements acquired were then investigated in terms of magnitude and phase. Combined analysis of these two terms suggests that it is indeed possible to discriminate between different tissues using the developed instrument. This is a highly motivating preliminary result that demonstrates the potential of the technology and justify the investment of further efforts towards a clinically usable system.