Studies On Measurement Methods Of Young's Modulus Of Soft Tissues

Young's modulus of soft tissues varies with pathological; it is a very important parameter of soft tissue. We can diagnose the desease by the variation of the Young's modulus of soft tissue. The objective of this study is to design an instrument to measure Young's modulus of soft tissue and use it in clinic.An integrated sensor which is built by linking a force sensor and an ultrasonic sensor in series contacts soft tissue closely. Loading and unloading the integratd sensor, the force singal and ultrasound signal are amplified, and the signals amplified are converted to digital signal by A-D convertor, the digital signals then are input to a DSP (Digtal Singal Processor). The thickness of the soft tissue can be obtained by prcessing the saw ultrasound signals using Maximum methods and the deformation of soft tissue in different loads can also be obtained by processing the ultrasound echo signals using the correlation method. Force-deformation curve is drawn by fitting the force and deformation data. Young's modulus of soft tissue can also be obtained by inputing the deformation and force data into the Young's modulus model.FPGA (Field Programming Gate Array) is used to process the data and extend the measurement system in future. Several modules are designed by using VHDL language and schematic input method in top level. Simulation results are shown.Finally, Young's modulus-Deformation curves of pig's muscle, beef and sheep's muscle are obtained respectively. The experiment results show that different soft tissue has different Young's modulus-Deformation cures. Similarly, Young's modulus-Deformation cures are different between abnormal soft tissue and normal soft tissue.