Engineering Design And Implementation Of An Integration Freezing/heating Control System For Tumor Treatment

Tumor is a common disease,including benign tumor and malignant tumor.Malignant tumor is known as cancer,which accounts for 30% of all the diseases that results in the death of resident.What’s more,with the number cases rising sharply worldwide,the prevention and effective treatment of cancer has been more important. The tumor treatment equipment mainly used the either freezing or heating technology. But Freezing produced less destruction on nondense tumors while heating produced local high temperature.Combined freezing/heating techniques produce maximal destruction while maintaining hemostatic control.Minimally invasive treatment using heating/ freezing circulation technology combines the advantages of both, and it also avoids the limitations of using a single technology, which makes the technology have a potential application prospect in the treatment of tumors.Based on the above situation, the paper developed a control system using heating/freezing circule technology,which aimed at the treatment of substantial tumors.Concretely,the paper starts from the development of cryotherapy and analyzes cryogenic technology as well as freezing/heating techniques. Building further on this foundation,the paper combined freezing/heating techniques by using nitrogen as a refrigerant and heated air as heating medium.Then, the paper makes a detailed statement about biological damage mechanism in cryoablation.That’s the basis for determining the parameter,embodiment and control project. Whereafter,the liquid nitrogen cryoscalpel system and pipeline model are improved or designed reasonably by computing multiphase flow and heat transfer phenomena.Above all,the freezing/heating cycling control system is realized with MSP430F149 as Microprogrammed Control Unit(MCU).At last,the prototype machine is completed while the system is tested.The test shows that the combined freezing/heating device,which uses liquid nitrogen as a refrigerant and heated air as heating medium,works well both in refrigerating cycle and in rewarming cycle. In refrigerating cycle,the temperature of probe is less than-100°C while the temperature of cryo-probe body is always between 0°C and 37°C. Moreover,the maximum frozen surface area of isolated liver tissue is about 52 mm.In rewarming cycle,the temperature of probe is greater than 45°C while the temperature of cryo-probe body is between 0 and 37°C. In the cycle the probe could be cooled to-174 °C or heated to 55 °C. The results of the test suggest that the new platform that provided in the paper is warranted with the view toward application to the treatment of substantive tumors.In short,the paper provides an effective combined freezing/heating control system through the control of refrigeration and temperature while it has so many advantages such as low cost,environmental protection and higher market value.