Notice of Removal: High-frequency arrays and applications

Typical high-frequency ultrasound resolution of 30-100 μm can be achieved in soft tissue over a penetration depth of 10-20 mm. The short penetration depth and high resolution, make high-frequency ultrasound particularly suitable for use in guided endoscopic surgery. In these minimally invasive procedures, a set of surgical instruments are inserted into a small incision site along with a set of imaging tools, typically endoscopic optical cameras and light sources. The entire surgical procedure is done solely under image guidance. Such an approach has become standard of care for a very large number of surgical procedures including those of the brain, colon, pancreas, uterus, bowel, etc. Recently, our group has developed a high-frequency array-based forward-looking ultrasound endoscope, that is suitable for guiding endoscopic procedures and providing depth resolved information. The packaged form factor for this imaging array has been miniaturized down to just a few millimetres, and the imaging performance has been characterized on ex-vivo and in-vivo tissues. A summary of the latest high frequency technology will be first be presented followed by a detailed performance characterization of our group's endoscope in combination with our high frame-rate high-frequency electronic beamformer. Future and prototype versions of high-frequency array transducers in-development will be discussed that incorporate 3D volumetric imaging, shear wave elastography, and co-registered histotripsy.