Development of an ultrasound indentation system for biomechanical properties assessment of soft tissues in-vivo

An ultrasound indentation system for biomechanical assessment of soft tissues in-vivo was developed. The system consists of a hand-held pen-size indentation probe, an ultrasound pulser/receiver device, a load cell driver/amplifier, a personal computer with two AD cards for digitizing ultrasound signal, force signal respectively, and the corresponding software. The probe comprises of an ultrasound transducer and a load cell. The thickness and the transient deformation of the soft tissue was determined from the ultrasound signal. Validation experiments were performed on porcine tissues. Force and deformation acquired with the present system were in good comparison with those obtained from a Housfield material testing machine. A quasi-linear viscoelastic layer model was used to simulate the data to get the material constants. The testing system is also suitable for multi-layers study.