Non-Invasive Detecting System For Gastrointestinal Tract And Magnetic Lacolization Technoloty & Experiment For Biotelemetric Capsule

Supported by the Research Fund for the Doctoral Program of Higher Education (No.20040248033), the National Natural Science Foundation of China (No. 30570485) and the 863 program (No.2006AA04Z368), this thesis develops the noninvasive detecting system for gastrointestinal tract and researches magnetic localization for the biotelemetric capsule. The thesis tries to find a magnetic localizing method which is feasible, practical and portable in principle.The thesis investigates collectivity project of the biotelemetric capsule. For simplification and extensing its functions easily, the biotelemetric capsule includes power module, RF communication module, signal processing module and sensors module.The thesis analyzes ultrasonic localization and magnetic localization technology for the biotelemetric capsule, and the magnetic localization technology is the key. The technology includes two ways of static magnetic localization and alternating magnetic localization. Magnetic mark method is a typical static magnetic localization method. The thesis discussed magnetic mark localization for detecting the biotelemetric capsule in GI based on magnetic field theory and magnetic detecting technology. The thesis analyzes the biotelemetric capsule's structure, too. According to magnetic finite element method, the thesis draws a conclusion which is a adaptive magnetic mark with profile dimension ofφ9×5mm, NdFeB45 material and cylindrical permanent magnet for localization. The four tri-axis sensors are fixed outside body for localization, and then the coordinate values of the biotelemetric capsule are solved by improved Newton-Raphson method. But there are two battery cells with high magnetic permeability metal shell. The thesis deducted calculating equation for the cells'affection via relative magnetic theory.The thesis discusses experiments of magnetic mark localization in detail, too. Besides, the author develops relative electrical circus to detect magnetic field utilizing magnetoresistive sensors.As a practice of static magnetic localization, the thesis developed tri-coil pulse inductive magnetic field method for the biotelemetric capsule's localization. The relative experiment indicates the method can localize the biotelemetric capsule, and the thesis compared it with the magnetic mark method and analyzes its advantages.Besides, the thesis discusses eddy current for localizing capsule. In order to make the method be realization, the author developed a tri-coil eddy current detector to detect long distance. The thesis deducted calculating equations for designing the detector. It has strong antijamming ability though it is very difficult to detect the capsule continuously, and the thesis analyses its localization effect. Excluding theses methods, the coil magnetic induction method has strong antijamming ability and is able to detect the biotelemetric capsule in long distance, too. As an alternating magnetic localization method, the thesis analyzes the method simply.