Load-indentation response of soft tissues with multi-layers

We described two methods in this paper to obtain the load-deformation distribution through the thickness of a human soft tissue layer using a pen-size indentation probe. The probe comprised of an ultrasound transducer and a load cell. The internal non-homogeneous deformation was derived from the ultrasound signals reflected from soft tissues. In the first method, cursors were used to track the peaks of ultrasound echo signals reflected from various interfaces. Load-deformation curves of different layer of soft tissues can be obtained accordingly. In the second method, a cross-correlation technique was employed to derive displacement distribution through depth with different indentation load applied. In-vivo experiments conducted at a site over proximal tibia demonstrated that the probe and associated data processing methods were feasible for determination of load-indentation response of multi-layered soft tissues.