Key Technologies Research On Micro Non-Invasive Gastrointestinal Bleeding Information Inspecting System

Gastrointestinal bleeding disease is impacting people's normal life. At the forepart of this kind of disease, the bleeding amount is little, which will hide the disease from being discerned by people. Once the bleeding amount is much enough, it will threaten people's life. Presently, there are no very satisfactory diagnosis methods and apparatus for gastrointestinal bleeding check and localization, especially for small intestine because of their single check information, short check time, discontinuity, range restriction, side effect and invasion. The gastrointestinal bleeding information includes bleeding existence, bleeding amount and bleeding position. The lack of grasping bleeding information results in the difficulty of gastrointestinal bleeding diagnosis. As the development of technology, people have asked for more requirement on MIT (the miniature invasive technology) and NIT (non-invasive technology) from modern medicine. So the research of micro non-invasive gastrointestinal bleeding information inspecting system is an important direction in the medical field.Under the support of National Natural Science Foundation of China (NO.30570485) and The National High Technology Research and Development Program of China (NO. 2004AA404013), combining the engineering technology and medical knowledge, this paper researches the bleeding information in gastro intestine and acquiring method in order to solve the questions of detecting, amount evaluating and location of gastrointestinal bleeding. The final purpose is to get new method and device for gastrointestinal bleeding diagnosis and treatment. Addressing on promoting the level of medical care, it is valuable both in research and social benefits.The main content and contributions of this paper are summarized as follows:1. The dissertation expatiates on the background, significance, purpose and main content for research; introduces the anatomical structure and basic physiological knowledge; analyzes the overview of gastrointestinal bleeding, normal diagnosis method and their shortages. As for the lacking of bleeding information, a non-invasive micro system for inspecting the gastrointestinal bleeding information is presented.2. The dissertation generalizes the content of gastrointestinal bleeding information composed of bleeding existence, bleeding amount and bleeding position etc which are the inspected objects of the researched system. The system's technique scheme is composed of blood micro sensing, biotelemetry and micro system localization in biotic tissue. The dissertation introduces the function of the researched micro system, designs the system structure and composition under the requirement of modularization and low consumption, and develops the prototype. The scheme and practicability on bleeding spot localization are researched by putting forward two localization methods, one of which is based on medical imaging technology, the other is based on magnetic intensity measurement.3. The dissertation researches the blood recognition and measurement in gastrointestinal tract, presents the basic requirement for sensing substrate selection, and succeeds in finding hemoglobin as the sensing substrate. By theoretic research on electrochemical measurement technology, the dissertation builds the relationship among electrode potential, electrode current and measured substrate, sets up the equivalent circuit of electrodes system. According on the theory analysis, the hemoglobin micro senor is allocated suitable measurement and control method.4. The three electrodes measurement system is designed, as well as potentiostatic ciucuit, micro current measuring circuit, signal generating and acquiring system. Under the platform some experiments are implemented for hemoglobin sensor verification including hemoglobin redox character verification, current response on different exiting potential and hemoglobin concentration, temperature dependence, pH dependence and stability on iron interference. The assembly and packaging for hemoglobin sensor both on traditional process and MEMS process are researched.5. The dissertation analyzes the electromagnetic characteristics of biotic tissue and the particularity of electromagnetic propagation in biotic tissue, and builds the power absorption models both in near filed and far filed of the radiation source which is set inside the biotic tissue. With some typical medical frequency and tissue materials the model is simulated in Matlab in order to research the power absorption depended on the frequency, tissue materials and some other factors. The research results are used to select a right frequency for wireless communication and design and test the wireless communication.Although the purpose of this dissertation has been reached, there still exists much research work to be done to make the system suitable for clinical applications.