AbstractNeedle intervention procedures are now frequently conducted in hospitals and clinics, because of the benefits of minimal invasiveness, possible manoeuvrability with needle deflection, and good compatibility with other medical procedures like imaging in laparoscopy. A lab-based prototype of ultrasound-actuated needle was previously designed in Dundee, which demonstrated some potential advantages in needle visualisation. However, the performance of this device was not consistent under different trial conditions because of the lack of understanding of the interaction between the ultrasonic needle and soft tissue. Better and in-depth understanding of this interaction mechanism will help on both how to better design this ultrasonic needle device and how to achieve better operational performance and acquire real-time feedback information for medical benefits in practice. The aim of this study is to investigate the needle-tissue interaction interface in the example of ultrasonic needle intervention in soft tissue, as so to achieve more stable performance for the ultrasonic needle device and to explore new functionalities for medical benefits with the ultrasound actuation.
First, mechanical properties of tissue mimicking phantom, ex vivo tissue and Thiel-embalmed tissue were characterised. Second, full characterisation was done on the designed prototype of piezoelectric needle device, and vibration optimisation was carried out with adaptive driving for high power output. Third, investigation on needle-tissue interaction with ultrasound actuation was performed on two main aspects: (1) ultrasound actuation effects with the reduction of insertion force, needle deflection and tissue damage; (2) ultrasound perception with the ability to detect the loading condition in operation by electrical impedance and frequency change. Finally, an anaesthesia case study was performed on needle visualisation and ultrasonic perception to serve as a proof of concept, with additional detailed explanation on the medical application background and working principles in technology.
From the results of experiments, numerical modelling and anaesthesia case study, it is concluded that: (1) vibration performance of ultrasonic needle device can be affected by varying loading conditions, and full characterisation and adaptive driving optimisation help to maintain stable performance for medical benefits with reduced penetration force, reduced needle deflection and better visualisation of needle shaft and needle tip; (2) the effect on electrical impedance by loading conditions can be used as useful feedback for the ultrasonic needle device, and the proposed ultrasonic perception function offers the capability to sense the different loading conditions by different types of tissue on the needle in operation to facilitate practitioners on targeting. All these explored benefits help the operational clinicians with more information for accurate needle placement and less risk for patient. To make it more clinically viable, future work should focus on the preclinical trials with an easy operational assembly in a fully integrated system.
|Date of Award||2015|
|Sponsors||Southwest University of Science and Technology|
|Supervisor||Zhihong Huang (Supervisor) & George Corner (Supervisor)|