The latest version of the corresponding national standard "B-mode ultrasound diagnostic equipment" (GB10152-2009), built in imitation of tissue material calibrated size and volume of the ellipsoid can detect three-dimensional image distortion. Dimensions approximately 150mm × 150mm × 160mm 1. TM organization built imitation material velocity: 1540 ± 10m / s (23 ± 3 ℃) 2. Built imitation organization TM material sound attenuation coefficient slope: 0.70 ± 0.05dB / cm / MHz (23 ± 3 ℃) phantom built two oval blocks, volume of about 60cm3, 10cm3. Dual scanning acoustic window.