The measurement of modulation transfer function in the image quality evaluation of CT system

Objective To evaluate the high resolution of CT system by measuring the modulation transfer function(MTF)of CT system.Methods The point source module in CT test phantom was scaned,the point spread function(PSF)and line spread function(LSF)of CT system were obtained,then Fourier transform was performed and the result was caliˉbrated.Results Using the processing program developed in our work,the MTF curve was plotted and the50%,10%,2%MTF values were given.Conclusion The measurement of modulation transfer function is a effective and objective method to reflect the true ability of CT system to distinguish objects.