3D printed calibration micro-phantoms for super-resolution ultrasound imaging validation

This study evaluates the use of 3D printed phantoms for super-resolution ultrasound imaging (SRI) algorithm calibration. The main benefit presented method is ability to do absolute micro-positioning sub-wavelength sized scatterers in a material having speed sound comparable that tissue. Stereolithography used printing soft calibration micro-phantoms containing eight randomly placed nominal size 205 μm × 200 μm. backscattered pressure spatial distribution evaluated show similar distributions from micro-bubbles as scatterers. structures are found through optical validation expand linearly all three dimensions by 2.6% after printing. SRI demonstrated phantom using λ/2 pitch 3 MHz 62+62 row-column addressed (RCA) probe. will act point targets, their below diffraction limit system used. Two sets 640 volumes features imaged, with an intervolume uni-axial movement 12.5 μm, emulate flow velocity 2 mm/s at frame rate 160 Hz. signal passed pipeline localise positions and track them across volumes. After compensating expansion, scaling 0.989 between distance calculated data designed distances. standard deviation variation scatterer along each estimate precision algorithm, expected be two limiting estimates (σ̃x,σ̃y,σ̃z) = (22.7 27.6 9.7 μm) (18.7 19.3 8.9 μm). In conclusion, this demonstrates determining accuracy volumetric algorithms.