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

• US 7,826,651 B2
• Filed: 03/10/2009
• Issued: 11/02/2010
• Est. Priority Date: 12/13/2004
• Status: Expired due to Fees

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Heer, Volker, Bohm, Stefan, Kolarjk, Martin, Durlak, Peter
• Primary Examiner(s): BHATNAGAR, ANAND P
• Application Number:
  US12/401,295
• Publication Number:
  US 20090169088A1
• Time in Patent Office: 602 Days
• Field of Search: 382/100, 382/128, 382/130, 382/131, 382/132, 128/922, 378 4- 27, 378/37, 378/38, 378/46, 378/63, 378/90, 378/92, 378/98.4, 378/98.6, 378/98.9
• US Class Current: 382/130
• 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. 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.