Analyzer-based Imaging (ABI) belongs to a broader family of phase-contrast (PC) X-ray techniques. PC measures X-ray deflection phenomena when interacting with a sample, which is known to provide higher contrast images of soft tissue than other X-ray methods. This is of high interest in the medical field, in particular for mammogram applications. This paper presents a simulation tool for table-top ABI systems using a conventional polychromatic X-ray source.
Analyzer-based X-ray phase contrast imaging (ABI) belongs to a broader family of phase-contrast (PC) X-ray imaging
modalities. Unlike the conventional X-ray radiography, which measures only X-ray absorption, in PC imaging one can
also measures the X-rays deflection induced by the object refractive properties. It has been shown that refraction
imaging provides better contrast when imaging the soft tissue, which is of great interest in medical imaging applications.
In this paper, we introduce a simulation tool specifically designed to simulate the analyzer-based X-ray phase contrast
imaging system with a conventional polychromatic X-ray source. By utilizing ray tracing and basic physical principles
of diffraction theory our simulation tool can predicting the X-ray beam profile shape, the energy content, the total
throughput (photon count) at the detector. In addition we can evaluate imaging system point-spread function for various
Phase contrast x-ray imaging, a new technique to increase the imaging contrast for the tissues with close attenuation
coefficients, has been studied since mid 1990s. This technique reveals the possibility to show the clear details of the soft
tissues and tumors in small scale resolution. A compact and low cost phase contrast imaging system using a conventional
x-ray source is described in this paper. Using the conventional x-ray source is of great importance, because it provides
the possibility to use the method in hospitals and clinical offices. Simple materials and components are used in the setup
to keep the cost in a reasonable and affordable range.Tungsten Kα1 line with the photon energy 59.3 keV was used for
imaging. Some of the system design details are discussed. The method that was used to stabilize the system is
introduced. A chicken thigh bone tissue sample was used for imaging followed by the image quality, image acquisition
time and the potential clinical application discussion. High energy x-ray beam can be used in phase contrast imaging.
Therefore the radiation dose to the patients can be greatly decreased compared to the traditional x-ray radiography.
A system using a wide slot beam and simple anti-scatter grid has been designed to
provide a localized map of tissue type that could be overlaid on the simultaneous
conventional transmission image to provide an inexpensive, low dose adjunct to
conventional screening mammography. The system was demonstrated to differentiate
between scatter peak angles corresponding to adipose tissue and carcinoma. Adequate
intensity in the coherent scatter image can be
achieved at a dose commonly used for screening
mammography. Depth information is obtainable
from the stereoscopic viewing angles. Phantom
imaging measurements and Monte Carlo
simulations show good agreement.
X ray diffraction reveals the nanoscale structure of both tissue and inorganic materials. Different materials can be distinguished and mapped by collecting the diffracted rays at different angles. Conventional diffraction measurements require a pencil beam and hence a small sample area to measure an accurate diffraction angle, so producing a mapped image requires a two dimensional scan. In order to to shorten the collection time for large areas, a slit system was
developed. An antiscatter grid was placed in front of the detector to select the desired diffraction angle. This device can
potentially be used in a scanning system to map the presence of target materials or in diagnostic radiology to detect cancerous tissues.
Focusing x-ray optics can be used to increase the intensity onto small samples, greatly reducing the data collection time for powder diffraction. Typically, the beam convergence is restricted to avoid loss of resolution since the focused beams broaden the resulting powder diffraction rings. However, the resolution, as defined by the uncertainty in peak location, can be much less than the peak width. Two types of x-ray optics, polycapillary and doubly curved
crystals, were used to focus x rays onto standard inorganic powder diffraction samples. Comparisons were made of system resolution and diffracted beam intensity using low power microfocus sources.