Development of a Test Environment for the Validation of needle mounted Vibroacoustic Sensors

In this paper, we describe a test environment for the development, performance validation, and optimization of a device to capture vibroacoustic signals during needle-tissue interactions using micro-electromechanical systems (MEMS) microphones. Vibroacoustic sensing provides the opportunity to improve in terms of accuracy, safety, and cost-effectiveness of minimally invasive surgery (MIS) not only by delivering real-time feedback, but also by improving surgeons navigation. In an attempt to explore this methodology, commercially available MEMS microphones were used in direct contact with conventional aspiration needle.Three prototype designs were constructed, tailored to maximize mechanical coupling between the needle and the microphone to reduce external noise interference and signal clarity improvement. The prototypes were assessed in a laboratory test setup with reference signals delivered by a speaker attached to the needle. The collected signals were processed by signal processing methods to evaluate their quality and fidelity. Results show that the final prototype which includes a secure 3D-printed adapter and direct microphone-needle coupling shows better signal acquisition and noise isolation performance.These results demonstrated the feasibility of MEMS microphones in real-time tissue differentiation in MIS. Future work will involve continuing to optimize microphone arrangement, enhance noise cancellation and investigate the utility of the system in alternative arrays of needle constructs and clinical settings.