Method and apparatus for generation of a digital x-ray image of an examination subject

• US 7,342,999 B2
• Filed: 08/03/2006
• Issued: 03/11/2008
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Johansson, Katrin, Mertelmeier, Thomas
• Primary Examiner(s): Yun; Jurie
• Application Number:
  US11/499,276
• Publication Number:
  US 20070036272A1
• Time in Patent Office: 586 Days
• Field of Search: 378/37, 378/62, 378/98.7, 378/98.8, 378/98.12, 378108-112, 378/115, 378/117
• US Class Current: 378/98.12
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• CPC Class Codes: A61B 6/542 involving control of exposure

Abstract

In a method and apparatus for generation of a digital x-ray image of an examination subject with an x-ray tube and a digital x-ray detector, a preliminary total dose required for correct exposure is determined using prior knowledge and a complete pre-image of the examination subject is acquired with a partial dose that is smaller than the preliminary total dose. A remaining dose is determined from the pre-image by image evaluation. A complete following image is acquired with this remaining dose, and the final x-ray image is assembled from the pre-image and the following image.

Claims

1. A method for generating a digital x-ray image of an examination subject, comprising the steps of:

determining a preliminary total x-ray radiation dose that is estimated, based on knowledge of the examination subject, to be necessary for obtaining a diagnostic image of an examination subject;

irradiating the examination subject with a partial dose of x-rays from an x-ray tube, that is less than said preliminary total dose, and detecting said x-rays attenuated by the examination subject with a digital x-ray detector to obtain a pre-image of the examination subject;

evaluating said pre-image to determine a remaining radiation dose, that has no fixed relation to said preliminary total dose, needed to produce the diagnostic image of the subject;

irradiating the examination subject with x-rays from said x-ray tube at said remaining radiation dose and detecting said x-rays attenuated by the examination subject with said digital x-ray detector to obtain a following image; and

combining said pre-image and said following image to obtain a final x-ray image, as the diagnostic image of the subject.

2. A method as claimed in claim 1 comprising setting said partial dose in a range between 40% and 60% of said total dose.

3. A method as claimed in claim 1 wherein said examination subject is a female breast, and determining said total dose, as a default setting for said x-ray tube, as being between 80% and 90% of a known average total dose for a two cm-thick compressed female breast.

4. An apparatus for generating a digital x-ray image of an examination subject comprising:

an x-ray tube that emits x-ray radiation that irradiates an examination subject;

a digital x-ray detector that detects said x-ray radiation attenuated by the examination subject; and

a control unit connected to said x-ray tube and to said digital x-ray a detector and having access to prior information about the examination subject, that determines a preliminary total x-ray radiation dose, using said prior information, that is an estimate of a dose necessary to obtain a diagnostic image of the examination subject, and that operates said x-ray tube at a partial dose, that is smaller than said preliminary total dose, to irradiate the examination subject with x-rays that are detected with said digital x-ray detector as a pre-image, and that evaluates said pre-image to determine a remaining x-ray radiation dose, having no fixed relation to said preliminary total dose, needed to produce the diagnostic image of the subject, and that operates said x-ray tube at said remaining dose to irradiate the examination subject with x-rays that are detected by said digital x-ray detector as a following image, and that combines said pre-image and said following image to obtain a final x-ray image, as the diagnostic image of the subject.