Detection of tissue properties using a piezoelectric vibration-based syringe

For safety improvement purposes, detection of tissue properties at the tip of the needle in real-time is helpful in controlling the movement of the needle in the operation of invasive surgical tools. According to the energy-based force model, the mechanical impedance of tissue can be represented approximately by a spring-damping model. In this study, a vibration-based syringe which adopts piezoelectric elements to vibrate the needle is proposed to identify tissue properties. In principle, by measuring the input electrical impedance of the vibration-based syringe, the mechanical impedance of tissue can be detected indirectly while the syringe exerts a vibration on the tissue. The model of the piezoelectric driven syringe and the procedure for evaluating the electromechanical interaction are given, and the mechanical impedance of tissue is evaluated by simulation. The proposed detection method has potential for applications of identifying tissue properties in epidural punctures and estimation of the degree of ablation in thermal surgery systems.