The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 08, 2004
Filed:
Oct. 18, 2001
John M. Dobbs, Hamilton, MA (US);
Analogic Corporation, Peabody, MA (US);
Abstract
An apparatus and method is provided for stabilizing CT number calculations by a CT system against fluctuations in the x-ray source voltage due to voltage source drift. A voltage reference level is established, by adjusting the voltage to the value which yields the correct CT number for a sample having a known CT number value. The x-ray energy spectrum measured by a kV meter is used to maintain the voltage constant at this reference level. The kV meter has a principal detector that generates a first intensity magnitude of the x-rays, and an auxiliary detector that generates a second intensity magnitude. The auxiliary detector includes an absorber that preferentially absorbs x-ray photons having a relatively low energy. A feedback controller provides to the voltage source a voltage control signal, which is continuously adjusted as a function of the first and second intensity magnitudes, so as to maintain the voltage constant at the reference level.