Sistema de biotelemetria passiva e técnica de medição para aquisição da impedância elétrica de tecido animal Post mortem

Abstract

This work describes the development of a technique for the measurement of the bioimpedance of animal tissues by means of a passive biotelemetric system, which is made up of two sensor units, each one composed of only an inductor and electrodes, and two reading units that consists of a reading coil in series with a capacitor and with a resistor (series RLC circuit). This technique allows the acquisition of the real and imaginary parts of the bioimpedance through the measurement of the module and phase parts of the input impedance of the proposed biotelemetric system. In order to characterize the object of measurement, some experiments were performed, employing post mortem animal tissue samples (bovine meat). The respective results are presented and discussed in details. Based in these results, the biotelemetric system was specified and implemented. With the purpose to validate the measurement technique and the biotelemetric system, bioimpedance models has been used, leading to measurement errors down to ± 4% to the real part of the bioimpedance. Experiments were carried out using the biotelemetric system and vacuum packed bovine meat samples with sensor units. As a result, it was possible to obtain the ratio between two real parts of the bioimpedance at two distant frequencies, also known as Py parameter, and the anisotropy ratio of meat samples. Besides that, this work also describes a novel simple method to measure the phase difference between two sinusoidal signals and an equipment to measure the module and phase of the input impedance of the biotelemetric system.