Daxsonics is pleased to sponsor the Dalhousie Engineering Capstone Conferece

The team at Daxsonics is looking forward to learning what the senior year engineering students have achieved through their time at Dalhousie University. The Capstone Projects integrate course work and showcase the students engineering design skills. 

We are looking forward to the presentations! 

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Daxsonics Executive Team published with the Acoustical Society of America

Daxsonics executive team, Jeff Leadbetter, Rob Adamson and Jeremy Brown have been published with the Acoustical Society of America. Research conducted on the in vivo measurement of the basilar membrane vibration in the unopened chinchilla cochlea using Daxsonics' own 10ERS4 Single Channel Pulser/Receiver began prior to the incorporation of the company. 

Daxsonics Affiliates at IEEE Ultrasonics: Real-time, 45 MHz, Split-Aperture Phased Array Beamformer with Efficient Sign Coherence Grating Lobe Suppression

Christopher A. Samson, Katherine Latham, and Jeremy A. Brown
School of Biomedical Engineering. Dalhousie University Halifax, Canada

Abstract—A digital variable sampling high-frequency beamformer implementing real-time grating lobe suppression is described. The system is tested using a semi-kerfed 64 element 45 MHz phased array with 1λ element pitch. The grating lobe suppression is facilitated with the sign coherence factor (SCF) and split-aperture transmit beamforming techniques. A new split-aperture transmit technique called “sub-aperture probing” (SAP) is described, experimentally validated, and compared to previously developed split-aperture techniques with respect to grating lobe suppression. Grating lobe levels were suppressed to be 49 and 60 dB below the main lobe when using 2 split-apertures with a SCF weighting factor of 1 and 2. These levels were further suppressed to 51 and 66 dB below the main lobe when splitting the aperture into 4 evenly sized apertures. When using SAP with 16 elements for the sub-aperture, grating lobes were suppressed to 49 and 64 dB below the main lobe. SAP with 8 elements yielded improved results compared to SAP with 16 elements; suppressing grating lobe levels to 49 and 65 dB below the main lobe for the associated SCF weighting coefficients. Finally the grating lobe suppression performance was tested on a wire target embedded in a tissue phantom and the signal to tissue speckle levels were characterized. 

Daxsonics Affiliates at IEEE Ultrasonics: Real-Time Imaging, Targeting, and Ablation of Ex-Vivo Tissue Using a Handheld Histotripsy Transducer

Jeffrey Woodacre*, Thomas Landry, Jeremy Brown
Department of Biomedical Engineering Dalhousie University
Halifax, Nova Scotia, Can
ada Corresponding Author*: jwoodacr@dal.ca

Abstract—. In this work, we have developed a small, handheld histotripsy transducer where the ablation focus is imaged in real- time using a co-registered 45 MHz 64-element phased array endoscope. The construction of a 2 cm diameter, 40% volume fraction, strongly curved, PZT5A composite transducer capable of generating cavitation within tissue is outlined. The co- registered imaging and ablation tool was able to ablate a 1 mm x 0.5 mm x 0.5 mm volume below the surface of a chinchilla brain using a single 5 second, 1 kHz PRF, 10 cycle burst, without damage to the surface leading to the ablation site. Total electrical power draw during treatment was less than 4 W.