No abstract

No abstract

Orthopaedic surgery involves cutting through bone and the removal of bone, bone spurs or ligament. Ultrasonic surgical devices, employing an ultrasonically excited cutting blade, have demonstrated precision and accuracy in bone surgeries, allowing surgeons to carry out bone cutting in difficult-to-reach surgical sites. For surgical procedures in a confined space, a small surgical device has benefits, but for ultrasonic devices this results in a reduced amount of piezoceramic material in the transducer. This paper provides insights into the trade-offs between the volume of piezoceramic material, location of the piezoceramic rings, resonant frequency and the achievable vibration amplitude. Bolted Langevin-style Transducers (BLT) are adopted for this study. Experimental results show that a similar level of vibration displacement can be achieved at a much lower input voltage with a higher quantity of piezoceramic elements. However, the associated nonlinear behaviour is exacerbated. Locating the piezoceramic elements at the longitudinal displacement node is critical, in order to maximise the ultrasonic energy transfer.

The acoustic impedance and attenuation of chicken liver and gizzard muscle were measured over a frequency range of 1-10MHz. The results validated their use as ultrasound phantoms for brain and brain tumour respectively. These tissues were then used as an initial test of whether quantitative ultrasound (QUS) could differentiate between brain and brain tumour tissue-like materials. QUS is a technique which infers information about tissue microstructure, such as effective scatterer size (ESD) and acoustic concentration, through the backscattered power spectrum of insonated tissues. The ESD of the brain tumour phantom was significantly higher than that of the healthy brain phantom, (87.3 ± 8.6 μm vs 61.2 ± 5.8 μm). The distinction in scattering properties shows potential to use QUS in soft tissue cancer detection.