Resolution Optimization Of Micro CT And Application Research In Tooth Mineralization

Micro-CT has the characteristics of nondestructive detection and imaging,and can achieve micro-level imaging detection.It is a important imaging equipment in many research fields,such as biomedicine science,material science,microsystem processing,manufacturing and petroleum geology.The scanning process of high-resolution optocoupler micro-CT usually lasts for several hours.During this process,the stability of the system is easily affected by factors such as X-ray source spot drift,thermal expansion and detector temperature drift,which in turn affect the quality of threedimensional reconstructed images.In view of the above problems,the main work contents in this paper are as follows:1.A high-resolution optocoupler Micro-CT testing and imaging system is established.Based on the factors affecting the system resolution,key imaging indexes are determined by integration considering the imaging field of view and the application field.At last the devices are selected,then are built into he high-resolution optocoupler Micro-CT.The resolution of the system is tested by using optimized experimental parameters.2.The instability caused by focal spot drift and thermal expansion of the system is monitored.Firstly,the tungsten wire cross landmark is designed and manufactured independently.Secondly,the focal spot drift curve is calculated by the shift curve obtained from the tungsten maker projected image and the shift curve of the mechanical obtained by the capacitive displacement sensor which is caused by thermal expansion At last,the experimental results are analyzed and discussed,and the possible factors causing the error of focal spot drift test results are discussed.3.The quasi-quantitative evaluation of tooth density is carried out by using the built high-resolution optocoupler micro-CT system.Firstly,the reference area is used to determine the modulation transfer function of CT imaging system,and then the transfer function is deconvoluted with the image of observation area to realize the quasiquantitative evaluation of density in observation area.