Siemens Aktiengesellschaft

Martin Kolarjk

Stefan Böhm

Peter Durlak

Volker Heer

Philipp Bernhardt

Helmuth Schramm

Friedrich Koch

Ernst Peter Rührnschopf

A method for checking an x-ray diagnostic apparatus is provided. Fluoroscopic series of x-ray images of a technical phantom are digitally acquired and stored. Difference between a dynamic image and a background image is calculated. A measuring field is predicted. Priori information about the shape of a clinically relevant object is determined. Hough transformation on a gray value image corresponding to the difference is applied. Contrast of the object from the Hough-transformed gray value image is determined. A square of the determined contrast is calculated. A noise variance is calculated by determining a sum of a noise variance of a homogenous image region and a variance of the background image. A contrast-to-noise ratio of the determined contrast and the calculated noise variance is determined. A square of the contrast-to-noise ratio is dynamically averaged. A Clinical Relevant Fluoroscopy Performance index for the x-ray diagnostic apparatus is determined.

Method for operating an x-ray diagnostic apparatus for determining quality values

The invention relates to an angiographic x-ray diagnostic apparatus with an x-ray radiator having an x-ray tube, with a patient positioning table having a radiation-transparent positioning plate and mattress, with an x-ray detector, with an imaging system, an image processing unit and a measuring device to which the output signals of the x-ray detector are fed and which has a first device for determining a value determining the reproduction quality of clinically relevant objects, a second device for determining local variances of the noise in a homogenous image region of different x-ray images and a device for taking the ratio of the output values of the two devices.

X-ray diagnostic apparatus and method for operating an x-ray diagnostic apparatus for determining quality values

The invention relates to a method and an x-ray examination unit for analyzing and representing x-ray projection images with an x-ray examination unit, where the function relation b=&#x192;(J/J) is established between the attenuation value and a material-equivalent value as a function of the energy spectrum used, and for the purposes of projection representation, the magnitude of the material-equivalent value bof a specific material is represented as an image value.

Method for analyzing and representing x-ray projection images and x-ray examination unit

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Nürnberg, Germany

Martin Kolarjk