Modeling modulation transfer function based on analytical functions in imaging systems

The performance of the imaging systems such as CT, SPECT and digital radiography may be investigated by the modulation transfer function (MTF) in which the spatial resolution properties have been addressed. All physical aspects and technical subjects in the imaging system may be related to the proposed function, for instance, the amount of the X-ray energy varied the MTF. In this study, an analytical-parametric function is introduced to characterize the MTF together with the estimation of the cutoff frequency (f(c)) that it is able to obtain the information on the technical specifications of the system. The MTF curves at the various spatial frequencies were modified by the different parameters included in the proposed function to optimize the system toward prediction and design of the affective factors to improve the spatial resolution as well as the qualified maps. The simulated results were at agreement to the experimental ones published before. For the same spatial frequency, while LSF widened the MTF dropped and cutoff decreased. Also, the best LSF-MTF pair was at E of 65 keV plus fc of 22.86 lp/mm. The MTF was improved by increasing energy threshold because the probability of distinguishing events happening far away from a given pixel is diminished.