1. A measuring method for checking an x-ray diagnostic apparatus, the method comprising: digitally acquiring fluoroscopic series of x-ray images of a technical phantom and storing the acquired digital data; calculating a difference between a dynamic image and a background image; predicting a measuring field; determining a-priori information about the shape of a clinically relevant object; applying a Hough transformation on a gray value image corresponding to the difference; determining a contrast of the clinically relevant object from the Hough-transformed gray value image; calculating a square of the determined contrast; calculating a noise variance by determining a sum of a noise variance of a homogenous image region and a variance of the background image; determining a contrast-to-noise ratio of the determined contrast and the calculated noise variance; dynamically averaging a square of the contrast-to-noise ratio; and determining a Clinical Relevant Fluoroscopy Performance (CRFP) index for the x-ray diagnostic apparatus.