5. Ultrasound Imaging Radial Array: Design and Fabrication

In the previous chapter, we demonstrated that the use of low-frequency ultrasound results in adequate penetration depth in bone for the detection of cortical bone boundaries in pedicle bones. Finding the optimal acoustic design and material that would be best suited for imaging within the bone was also studied. Although all the experiments were performed with a single element transducer, we believe that to make the image guidance technique more acceptable to spine surgeons, it is necessary to use a method that avoids the need for mechanical transducer rotation. To achieve this, we have designed and fabricated a 32-element cylindrical imaging array that is intended to be used with phased focusing at a center frequency of around 2 MHz using an Ultrasonix^™ imaging system. This platform is an open-source ultrasound system that allows a variety of ultrasound transducers to be connected and controlled by the user.