| In modern times, due to the quick pace of life and irregular diet, cardiovascular disease has been the first killer of human health. So research on knowledge of cardiovascular has been the hotspot domestic and overseas. We can not wait any more to do some pointed, systematic, and scientific research and tackle the key projects. Because of the importance of human heart and complexity of its structure and working principle, most time we can’t operate and sample directly. Thus, it is so important to design a set of instrument which can reproduce the working situation accurately that it will offer a great platform for the development of relevance medical devices and study on cardiovascular surgery.The heart tissue could be considered as a precise, electric signal impelled diaphragm type volumetric pump with four one-way valves. The regular electrocardiosignal ensures the systole. The one-way valves provides enough pressure in small range action and keeps the one-way flow. Heart fibrous scaffolds offer effective support for the heart and the other structures. With the division of the heart work period, we clear how the heart systole and diastole with the cooperation of the valve. Then we analyse the factors of the haemodynamics and raise the parameter dimension of the phantom.To acquire the accurate heart modeling, we use CT to collect the heart image. Then we modify and do the three-dimensional reconstruction with medical image processing software Mimics. We design a kind of air bag structure outside the phantom to make it systole and diastole uniformly. The working air is pressed into the air bag by a piston. Using the reverse engineering module in Mimics, we import the three-dimension model into Solidworks to design the shell of the air bag and the port of interventional operation. So does the braced frame and recycled water tank. With STL file from the RP module in Mimics, we use RP equipment to make a female die and get a phantom with suitable material which fit the mechanical property.From the state parameter changing curve of the left ventricle, we derived how the piston mechanism moves with the power source. Using the Shelly Medical and medical center of University of Amsterdam for reference, we choose to use mechanism to drive directly and servo motor to control accurately. Connect it with the cam gear which can adjust its base radius. So the piston presses the working air into the air bag to pump the blood out of the phantom.At last, to measure the outflow of the phantom and check whether it meets the order of the parameter, we design a kind of flow acquisition system. The system is consist of GEMS Hall flow sensor, NI DAQ card and adjustable power. Then we compile a pulse collection program and a flow checking program with the software LabVIEW. During the research we also overcome some usual signal interference phenomenon which is generated by the magnetic field of the servo motor. We compare the data with the real to demonstrate whether the design of the phantom or the driving mechanism is reasonable. These data can be used as the important basis to control the motor and improve the structure design. |
