High-frequency ultrasonic airborne Doppler method for noncontact elasticity measurements of living tissues

Abstract

Functional measurement techniques and noncontact measurement techniques using ultrasound have been widely studied. However, only a few studies have addressed the possibility of noncontact elasticity measurements using airborne ultrasound. In this paper, we propose a novel noncontact measurement method that uses a high-frequency airborne ultrasonic transducer operating at 1 MHz. First, the fundamental characteristics of the proposed high-frequency airborne ultrasonic transducer were quantified both numerically and experimentally. Second, to validate the proposed method, experimental viscoelasticity estimations were performed. Young’s moduli and viscosity coefficients of three tissue-mimicking phantoms (Young’s moduli: 30 kPa with/without viscosity, 70 kPa) and chicken tissue samples were estimated using a piezoelectric actuator and the proposed airborne ultrasonic transducer. The estimated Young’s moduli and viscosity agreed with the reference values. Thus, the proposed system can be used for noncontact measurements of elasticity.