MTF evaluation SPECT imaging

One of the disadvantages in SPECT imaging is low spatial resolution. The determination of it has various ways which one of them is modulation transform function. M T F is ratio of output contrast to input contrast which is depend practically as the range of zero to one. M T F in the system depends on various factors. In this study a line source and N E M A line spread phantom are used to calculate M T F with various states and comparison with others until the best statues are created for imaging point of view quality image specific resolution and contrast. In this study a line source and N E M A line spread phantom with l mCi activity (count rate 10 k count) are used. Each one of them is placed in the middle and the longitude axis of the bed and is imaged by methods, planar and SPECT. Imaging is performed with various distances to detector and matrix sizes in two different conditions with and without scattering. Then a line profile is drawn on the images and line spread function is calculated for every on of them and M T F with fitting Gaussian curve and Fourier transform for all of the cases. In both methods (line source and N E M A line spread phantom) and in comparison with M T F, relation of M T F and distance to detector, with source and matrix size. By considering and comparison of effective factors in the image quality and M T F. We concluded that with measuring the imaging system M T F, the effect of the factors on the image quality could be assessed