METHOD FOR OPERATING AN X-RAY DIAGNOSTIC APPARATUS FOR DETERMINING QUALITY VALUES

• US 20090169088A1
• Filed: 03/10/2009
• Published: 07/02/2009
• Est. Priority Date: 12/13/2004
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Kolarjk, Martin, Heer, Volker, Durlak, Peter, Bohm, Stefan
• Granted Patent: US 7,826,651 B2
• Time in Patent Office: Days
• US Class Current: 382/132
• CPC Class Codes: A61B 6/504 for diagnosis of blood vessels, e.g. by angiography
• CPC Class Codes: A61B 6/583 using calibration phantoms
• CPC Class Codes: G06T 7/0002 Inspection of images, e.g. flaw detection
• CPC Class Codes: H04N 5/325 Image enhancement, e.g. by subtraction techniques using polyenergetic X-rays
• CPC Class Codes: Y10S 128/922 including image analysis

Abstract

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.

Claims

1-36. -36. (canceled)

37. 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.

38-40. -40. (canceled)