Study On Effect Of Radiofrequency Lesion On The Complex Impedance Of The Biological Tissue

Bio-impedance technology is a noninvasive impedance measurement techniques using the physical properties of biological tissues and organs for the extraction of biomedical information. Bio-impedance technique is a study which is mainly about the physical properties of biological tissue. It is a new type of technology developing fast in recent years. The technology has such advantages as cheap, safe and non-toxic. These characteristics make it a very popular technology in the field of biomedical research.Generally speaking, radiofrequency use the single frequency measurement method, this method can only be extracted to measure the amplitude of impedance. It can not measure the detailed parameters of the complex impedance of the biological tissue. In order to obtain physiological and pathological information about the biological tissue from biological tissue impedance, This paper put forward the method of multi-frequency measurement, designed and produced a bioelectrical impedance measurement platform based on virtual instrument. The main works are the as following:1. The hardware part designed and made a signal generating circuit used to excite the biological tissue, the advantage of this part is that it can produce current excitation signal with variable amplitude, frequency and phase; A programmable gain operational amplifier was increased in signal conditioning part, it enhanced the measurement accuracy of the system.2. The PC software designed a virtual instrument. The virtual instrument can not only control the hardware circuit but also get the magnitude, phase, real and imaginary parts and other datas of complex impedance of biological tissue; Using virtual instrument technology in the computer, a platform for data analysis of impedance information is established, it can process post-data of different impedances information.3. Using the complex impedance measurement of biological tissue system, With egg white tissue and liver tissue as measured object, we designed a series of experimental measurements respectively. We obtained a lot of data from egg white tissue and liver tissue while damage them. The graph of the data verifies that the complex impedance of the biological tissue can really reflect physiological and pathological conditions of biological tissue.