Radiographic imaging using an effective rotationally symmetrical focal spot

A mathematical model is presented for predicting the effect of rotation on certain types os asymmetric focal spot intensity distributions. Experimental rotational techniques are used to obtain rotationally symmetric, gaussian-like focal spot distributions from existing asymmetric distributions. Radiographic examples are shown which illustrate the resulting imaging effect of such rotationally symmetric focal spots compared to existing focal spots. In particular, images of resolution test patterns and simulated blood vessels are used to examine some of the radiographic consequences (contrast transfer and spurious imaging) of the use of differing types of focal spot intensity distributions, and to question the utility of single number characterizations of asymmetric focal spots.