Modified Method In Measurements Of X-Ray Focal Spot Modulation Transfer Function

The Modulation Transfer Function (MTF) of an x-ray focal spot has been obtained without the aid of a microdensitometer. The modified method described in this study utilizes radiographic magnification techniques to eliminate the need for a microdensitometer. In this study a radiographic magnification factor of 25X or higher has been employed to obtain the slit-camera images of x-ray focal spots. The Line Spread Function (LSF) is obtained by scanning the focal spot slit-camera image acquired with the modified method on an ordinary densitometer equipped with a 0.2 mm aperture. The MTF is subsequently calculated from the LSF and compared with the MTF that was obtained by means of the traditional method. The results show good agreement between the MTFs obtained by these two methods.