The Development Of Novel Microwave Therapy Apparatus And The Research Of Its Application In Microwave Phantom

Objective: 1.Microwave technology is rarely used clinically in treating orthopedic diseases in China and domestic microwave therapy apparatuses used currently are relatively outdated,so the target of this research is to independently design and develop a novel microwave therapy apparatus which is mainly used for the treatment of orthopedic diseases.2.To build the microwave hyperthermia phantom and to investigate the warming effect of the novel microwave therapy apparatus on the microwave phantom,thereby providing a basis for subsequent animal or clinical experiments.Materials and methods: 1.The microstip antenna element was designed according to the theory of microstip antenna and microstrip array antenna.The basal plate was selected and its size and mode of feeding were determined.On this basis,the 16 element microstrip array antenna was designed,and the manufacture of microwave therapeutic instrument was completed;2.According to the biological characteristics of normal human muscular tissues,the microwave hyperthermia phantom which has the same dielectric property with that of human muscular tissues was made using stratified temperature,sodium carboxymethyl cellulose,sodium chloride,sodium hydrogen sulfite,deionized water and other materials;3.In this experiment,TP3001 thermometer was adopted to carry out stratifiedtemperature measurement on the phantom undergone in vitro radiation given by the microwave therapy apparatus.The specific practices are as follows:First,the well configured microwave phantom was placed in a thermostatic water bath container,with the water temperature maintained at 37℃.Then the container was stood still for a while to make the phantom temperature consistent with that of water.The microwave therapy apparatus was started to measure the temperature before microwave irradiation.Second,the phantom was heated 15 cm and 20 cm from the microwave antenna,the heat-up time was set to be 15 minutes,the temperature was measured every three minutes,and the phantom temperatures respectively 2cm,4cm,6cm and 8cm from the phantom surface were obtained.Third,the sleep key on the display screen was pressed to turn the microwave emitted by the signal source into impulse wave from continuous wave.The above steps were repeated.Finally,the above heating procedure was repeated 3 times,and the average of measured values in the three repeated experiments was taken as the final value;4.All the collected data was analyzed and sorted up to get the distribution law and temperature rising characteristic of the microwave thermal field in the phantom.Results:(1)The microwave therapy apparatus used a 4x4,16-element microstrip array antenna,which was used as microwave hyperthermia antenna.The antenna had characteristics of small size,high focus,high gain and low side lobe.The designed and manufactured microwave signal generator was equipped with pulse mode and continuousmode,and the display screen of signal source adopted LCD touch screen.(2)In this experiment,the phantom made of acrylamide,sodium carboxymethyl cellulose,sodium chloride,sodium hydrogen sulfite,deionized water and other chemical materials has identical dielectric property to human muscular tissues and can replace the human body for experiment research.(3)The radiated microwave hyperthermia phantom has certain microwave thermal field distribution law and temperature rising characteristics.Modulating the signal source can turn microwave into impulse wave from continuous wave.The general tendency of phantom temperature rising before and after the modulating was that the maximum temperature first increased and then decreased with the increasing depth of the phantom,and the closer the phantom to the antenna,the higher the phantom’s temperature.Before the modulating,the maximum temperature of the phantom tended to be stable at about 9 minutes,and it came to a stable state after the modulating 3 minutes earlier.Moreover,before and after the modulating,the temperature rising of phantom at the depth of 2cm to 6cm was fast and the temperature required for treatment was reached.On the contrary,the temperature rising at a depth of8 cm under the surface of the phantom was slow,and the temperature required for treatment was not achieved.Conclusion:(1)Microwave therapy apparatus can be applied clinically to radiate the human body,so as to achieve to the treatment purpose with the thermal and non-thermal effects of microwave on human body;(2)A novel microwave therapy apparatus with medical functionsand frequency of 915 MHz was preliminarily designed and manufactured,which possesses the advantages of simple equipment,convenient operation,high security,convenient carrying,high efficiency,etc..(3)The microwave hyperthermia phantom has identical dielectric property to human muscular tissues as well as favorable electromagnetic simulation ability.(4)In this study,both the continuous wave and impulse wave of the microwave therapy apparatus have the function of heating and the temperature required for clinical treatment can be achieved with both waves,thus providing a theoretical basis for the subsequent animal and clinical experiments.