X-ray phase imaging: Demonstration of extended conditions for homogeneous objects

University of Melbourne, Melbourne, Victoria, Australia
Optics Express (Impact Factor: 3.49). 07/2004; 12(13):2960-5. DOI: 10.1364/OPEX.12.002960
Source: PubMed

ABSTRACT We discuss contrast formation in a propagating x-ray beam. We consider the validity conditions for linear relations based on the transport-of-intensity equation (TIE) and on contrast transfer functions (CTFs). From a single diffracted image, we recover the thickness of a homogeneous object which has substantial absorption and a phase-shift of --0.37 radian.

Download full-text


Available from: David Paterson, Feb 18, 2014
22 Reads
  • Source
    • "In phase-retrieval tomography, the measured projected intensity data at the detector in each angular position are used to retrieve the projected quantitative phase map of the sample which in turn is subjected to a filtered back-projection algorithm to obtain the three-dimensional distribution of the sample phase (Arhatari et al 2010). There are several methods (Nugent et al 1996, Turner et al 2004, Cloetens et al 1999) available for phase retrieval. For complex materials like the cortical bone (where samples consist of material with varying density), two or more plane phase-retrieval steps are required to obtain the quantitative phase in one projection. "
    [Show abstract] [Hide abstract]
    ABSTRACT: By applying a phase-retrieval step before carrying out standard filtered back-projection reconstructions in tomographic imaging, we were able to resolve structures with small differences in density within a densely absorbing sample. This phase-retrieval tomography is particularly suited for the three-dimensional segmentation of secondary osteons (roughly cylindrical structures) which are superimposed upon an existing cortical bone structure through the process of turnover known as remodelling. The resulting images make possible the analysis of the secondary osteon structure and the relationship between an osteon and the surrounding tissue. Our observations have revealed many different and complex 3D structures of osteons that could not be studied using previous methods. This work was carried out using a laboratory-based x-ray source, which makes obtaining these sorts of images readily accessible.
    Physics in Medicine and Biology 08/2011; 56(16):5265-74. DOI:10.1088/0031-9155/56/16/012 · 2.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We consider image formation for the phase-contrast radiography technique where the radiation source is extended and spatially incoherent. A model is developed for this imaging process which allows us to define an objective filtering criterion that can be applied to the recovery of quantitative phase images from data obtained at different propagation distances. We test our image model with experimental x-ray data. We then apply our filter to experimental neutron phase radiography data and demonstrate improved image quality.
    Review of Scientific Instruments 11/2004; 75(12):5271-5276. DOI:10.1063/1.1819652 · 1.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An image model for phase contrast in projection radiography of complex objects is presented and tested experimentally. The model includes the wavelength distribution of the radiation. The model is used to optimize the contrast of a radiograph of a piece of aluminium containing a fine crack.
    Review of Scientific Instruments 11/2005; 76(11). DOI:10.1063/1.2135275 · 1.61 Impact Factor
Show more