Browse Prior Art Database

GRATING INTERFEROMETER FOR X-RAY SPECTRUM SHAPING

IP.com Disclosure Number: IPCOM000198292D
Publication Date: 2010-Aug-03
Document File: 6 page(s) / 152K

Publishing Venue

The IP.com Prior Art Database

Abstract

A grating technique for mechanical tuning of X-ray source spectrum is disclosed. This grating technique proposes a grating interferometer for mechanical tuning of X-ray source spectrum of a conventional broadband X-ray source. Such a grating technique provides a cost effective mechanical method for spectrum switching.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 40% of the total text.

Page 1 of 6

RP13453

BRIEF ABSTRACT

    A grating technique for mechanical tuning of X-ray source spectrum is disclosed. This grating technique proposes a grating interferometer for mechanical tuning of X-ray source spectrum of a conventional broadband X-ray source. Such a grating technique provides a cost effective mechanical method for spectrum switching.

KEYWORDS

    Dual energy, X-ray imaging, X-ray source spectrum, grating interferometers, Bremsstrahlung spectrum, coherence, diffraction

DETAILED DESCRIPTION

    Generally dual energy X-ray imaging is required for material differentiation in medical and inspection/security applications. An X-ray absorption coefficient of a material usually consists of two components. One component of the X-ray absorption coefficient is due to photoelectric effect and the other is due to Compton scattering. Recording of X-ray attenuation images with two distinct source spectra allows separation of the two X-ray absorption components and thus the material composition of the image pixels may be estimated. For such applications a repeatable method to modify the source spectra is required to achieve dual energy X-ray imaging.

1

GRATING INTERFEROMETER FOR X-RAY SPECTRUM SHAPING

Page 2 of 6

RP13453

    Currently, several conventional techniques are employed to obtain dual energy information. Such techniques include fast switching of X-ray tube voltage, multi-layered detectors with different detector layers being sensitive to different spectral ranges, OR detectors with checkerboard pattern of filters, two separate sources operating at different kilovolt potential (kVp) and multiple source-target/ filter combinations. However such conventional techniques typically involve increased hardware costs for achieving repeatable and stable spectrum switching performance.

    Hence there is a need in the art for a cost effective, mechanically stable and repeatable method for switching X-ray source spectrum between two or more spectral profiles.

    According to the present invention a grating interferometer for mechanical tuning of X-ray source spectrum is utilized. Such a grating interferometer uses a conventional broadband X-ray source. Tuning of source spectrum is achieved by mechanical translation of a diffraction grating. The grating interferometer achieves spectrum switching mechanically by employing diffraction gratings as the only additional hardware in existing X-ray imaging systems.

    Typically X-ray interferometers require coherent radiation as generated by synchrotrons. The present grating technique utilizes a conventional broadband X-ray tube operating at a constant voltage. The coherence requirements are satisfied by careful selection of the grating periods and distances between the gratings. The grating interferometer consists of three diffraction gratings which are placed in front of a conventional X-ray source. The first two gratings produce a periodic pattern of colorful fringes at the third grating. The third grating is an amplitu...