The Research Of Magnetic Medium Guidance Hyperthermia Control System Research

Hyperthermia is a newly developed technique, which main subject investigated is magnetic medium guidance hyperthermia. Control system is the key that this technique can be able to operate safely, control warming up effectively, kill tumour cells. It deals with relative theory and technique of multi-fields such as biomedicine, control theory of detection and computer science.This task roots in "The research of the new method hyperthermia that metal particle induces tumour in alternating magnetic field"- National Natural Science Foundation projects in 2004 undertaken by Guangdong University of Technology. In allusion to magnetic medium guidance hyperthermia equipment researched at present, a safe and effective control system is required to be researched, and also some relative control experiments have been done after the invention of the first hyperthermia equipment.Magnetic medium guidance hyperthermia and the relative theory of control technique are the base of this control system, of which the detection and control of temperature are the key points. The paper introduces Maxwell equations, Pennes equations of biology heat exchange and test control theory of temperature and magnetic field, and also make certain the best detecting method suitable to this control system. According to the temperature of tumour cells detected, Dahlin algorithm adapted to time-delay system of this text is adopted, closed-loop control of the temperature of tumour cells is carried out by controlling the output power of introduction heating.According to the control theory and related heating equipment needs analysis, control system of this paper is developed. The control system of this paper has two kinds of monitor modes: frontend machine and PC. Frontend machine is centred by micro-controlled machine LPC2114 of embedded. PC is mainly to memorize and inquire about patients' data, show and judge the correlative parameter of therapy, produce related curve and patients' case, realize Time-delay control algorithm, have real time monitoring of this system by sending related parameter of the equipment to frontend machine by serial-port, provide some related software interfacesBased on the research of current temperature and magnetic field detection principles and methods, and combine with the work environment of control system, functional circuit centered by LPC2114 control circuit and control system is designed combining the requirements for the working environment of this control system. It can detect produced field intensity and the temperature of tumour tissues, output control signal of adjustable duty ratio by Time-delay control algorithm, adjust the output power of induction heating power source to change the alternating field strength, then the temperature, finally realize the accurate control temperature of target area. The design of anti-jamming technique makes this system have strong ability and stability of anti-jamming electromagnetism.In the process of writing this paper, I myself was engaged in the related study of magnetic medium guidance hyperthermia in Medical Physics and Engineering Institute Tsinghua University, and also participated in development activity of the control system of magnetic medium guidance hyperthermia in NUCTECH COMPANY LIMITED, this played an important role for my paper.