Design Of Respiratory Control System For Radiotherapy

The radiotherapy is one of the main means of treatment of malignant tumor, and the treatment technology has been rapidly developed in recent years. The precise radiotherapy has become the important development direction of radiotherapy by the superiority of killing the tumor cells and protecting the normal tissues in the maximum limit. The precise radiotherapy also faces some difficult problems. Some human organs will change the position along with human respiratory movement such as lung, liver, mammary gland and so on. This kind of position change will bring the precise radiotherapy bigger deviation of tumor target volume, and even cause partial tumors to be separated from the target volume. If the doctor enlarges the margin of target volume, which will make more benign tissue receive the radiation.To solve the problem of precise radiotherapy, respiratory control technology comes into being. The commonly used respiratory control technology includes passive compression technology, deep inspiration breath-hold technology, real-time tracking radiation technology, active breathing control technology, respiratory gating technology and so on.Both active breathing control technology and respiratory gating technology have corresponding products, which are all designed by medical equipment companies of Euro-American country. In the resent years, active breathing control technology is the focus area, and has many clinical applications, which could effectively reduce human respiratory movement influence on precise radiotherapy after research. In our country, radiotherapy departments in tumor hospital and general hospital of developing precise radiotherapy have demand to introduce this equipment. However, the medical equipment of Euro-American country is very expensive, which put the heavier economic burden on hospital and patient.The main task of the subject is to develop a set of respiratory control system for radiotherapy. The system chooses flow-type sensor and control box of the small lung function machine to monitor patient's respiratory movement, the control box converts differential pressure signal of flow-type sensor into digital signal, which is sent to computer via serial port. The means of control respiratory access open/close is that balloon automatic controller deflate/inflate to small balloon set in the respiratory access. The realization of system software is transforming the software of lung function machine.This system carried out simulation experiments and clinical trials respectively. The experimenter simulated the system, and tested the realization of each kind of function. Ten patients with peripheral non-small cell lung cancer have used the system in the clinical trials. Firstly, the project carried out statistical analysis about displacement degree of lung tumor along with the respiratory movement in three-dimension, right and left, back and front, foot and head. Secondly, the project collected CT images and made radiotherapy plans respectively in two cases, freely breathing and inspiration breath-hold with the respiratory control system, and carried out statistical analysis respectively about gross tumor volume and planning target volume of two plans.