Development and feasibility assessment of open-UST: A low-cost, open-source, manufacturing framework for an ultrasound tomography research system
Widely available and re-configurable UST hardware is needed to enable the ongoing development of advanced UST imaging techniques. Having access to a physical UST transducer array in-house accelerates algorithm development, compared to relying solely on open databases of experimental data from other groups. Widely available UST hardware also allows new algorithms to be tested on real data from physical transducers, which is a more robust evaluation than using synthetic data. In this work, an open-source 256-element transducer ring array was developed (morganjroberts.github.io/open-UST) and manufactured using rapid prototyping, with a material cost of ∼£2k. This is the first example of a low cost opensource array design with a specification suitable for UST imaging, and was made possible through novel fabrication methods, resulting in 0.46° and 1.17° elevational and lateral beam axis skew angles, a 104 μm standard deviation in on-axis element position, and a ±18.9 μm deviation in matching layer thickness. The nominal acoustic performance was measured using hydrophone scans and UST watershot data, and the 61.2 dB SNR, 55.4° opening angle, 16.3 mm beamwidth and 528 kHz cutoff frequency (-40 dB) were found to be similar to existing systems, and compatible with full waveform inversion reconstruction methods. The inter-element variation in acoustic performance was typically