Measurement and simulation of steered acoustic fields generated by a multielement array for therapeutic ultrasound

This data was collected to evaluate the effect of element size, element positions, relative source pressure variations, and electrical crosstalk on the accuracy of modelling pressure fields generated by a 555 kHz 32-element ultrasonic array. The transducer was assembled from 32 individual 3mm diameter plane circular piezo-ceramic elements (XDR107, Sonic Concepts, Bothell, WA) arranged in a pseudorandom configuration in a three-dimensional (3D) printed spherical cap holder, with radius of curvature 80mm and aperture diameter 70 mm. Measurements were performed with a 0.2 mm PVDF needle hydrophone (Precision Acoustics) to characterise the source under quasi steady state conditions (35 cycle burst). All measurements were acquired using an automated scanning tank filled with degassed, deionised water. The transducer was mounted in a fixed xyz position. Hydrophones were mounted on an automated xyz stage, with manual tilt, rotate adjustment. Planar scans in the prefocal region were obtained to charaterise the source under 3 driving conditions: with all elements driven with equal amplitude and phase, with phase corrections applied which were obtained from hydrophone measurements at the geometric focus position, and with these corrections plus further geometrically calculated phase offsets to steer the array focus to x = 20 mm, y = -20 mm. A further set of line scans passing through the focus was obtained for the equalised unsteered case, focal steering to x = -20 mm y = 20 mm, and 8 further steered focal positions. In total, this study contains 33 datasets contained in 1 file, the corresponding figure or table in the paper is given in brackets. 1. Planar scan at 56 mm, unsteered without phase corrections 2. Planar scan at 56 mm, unsteered with phase corrections from hydrophone measurements at geometric focus (Fig 1) 3-5. X,Y,Z line scans through the focus, unsteered with phase corrections 6. Planar scan at 50 mm, with phase corrections + steered to x = 20 mm, y = 20 mm 7-9 X,Y,Z line scans through the focus, with phase corrections + steered to x = 20 mm, y = 20 mm 10-12 X,Y,Z line scans through the focus, with phase corrections + steered to z = 100 mm (Fig 2a) 13-15 X,Y,Z line scans through the focus, with phase corrections + steered to z = 70 mm 16-18 X,Y,Z line scans through the focus, with phase corrections + steered to x = 5 mm 19-21 X,Y,Z line scans through the focus, with phase corrections + steered to x = 10 mm 22-24 X,Y,Z line scans through the focus, with phase corrections + steered to x = 20 mm (Fig 2b) 25-27 X,Y,Z line scans through the focus, with phase corrections + steered to x = 40 mm (Fig 2c) 28-30 X,Y,Z line scans through the focus, with phase corrections + steered to y = -10 mm 31-33 X,Y,Z line scans through the focus, with phase corrections + steered to x = 10 mm, y = -10