Quantification of the depth effect of tomographic and section imaging devices

In order to compare their depth effect, the line source response function at right angles to the image plane was measured using two tomographic and one section-imaging device. It was found that the full- width-at-half-maximum and modulation transfer functions do not adequately measure the capability of a device to resolve structures as a function of depth. A new quantity, called specificity, is proposed which measures the degradation of resolution of one image plane relative to an adjacent image plane as a function of frequency.