Analyzer crystal based imaging techniques such as diffraction enhanced imaging (DEI) and multiple imaging radiography (MIR) utilize the Bragg peak of perfect crystal diffraction to convert angular changes into intensity changes. These X-ray techniques extend the capability of conventional radiography, which derives image contrast from absorption, by providing a large change in intensity for a small angle change introduced by the X-ray beam traversing the sample. Objects that have very little absorption contrast may have considerable refraction and ultra small angle X-ray scattering (USAXS) contrast thus improving visualization and extending the utility of X-ray imaging. To improve on the current DEI technique this body of work describes the design of an X-ray prism (XRP) included in the imaging system which allows the analyzer crystal to be aligned anywhere on the rocking curve without moving the analyzer from the Bragg angle. By using the XRP to set the rocking curve alignment rather than moving the analyzer crystal physically the needed angle sensitivity is changed from ìradians for direct mechanical movement of the analyzer crystal to milliradian control for movement the XRP angle. In addition to using an XRP for the traditional DEI acquisition method of two scans on opposite sides of the rocking curve preliminary tests will be presented showing the potential of using an XRP to scan quickly through the entire rocking curve. This has the benefit of collecting all the required data for image reconstruction in a single fast measurement thus removing the occurrence of motion artifacts for each point or line used during a scan. The XRP design is also intended to be compatible with combined imaging systems where more than one technique is used to investigate a sample. Candidates for complimentary techniques are investigated and measurements from a combined X-ray imaging system are presented.

Analyzer crystal based imaging techniques such as diffraction enhanced imaging (DEI) and multiple imaging radiography (MIR) utilize the Bragg peak of perfect crystal diffraction to convert angular changes into intensity changes. These X-ray techniques extend the capability of conventional radiography, which derives image contrast from absorption, by providing a large change in intensity for a small angle change introduced by the X-ray beam traversing the sample. Objects that have very little absorption contrast may have considerable refraction and ultra small angle X-ray scattering (USAXS) contrast thus improving visualization and extending the utility of X-ray imaging. To improve on the current DEI technique this body of work describes the design of an X-ray prism (XRP) included in the imaging system which allows the analyzer crystal to be aligned anywhere on the rocking curve without moving the analyzer from the Bragg angle. By using the XRP to set the rocking curve alignment rather than moving the analyzer crystal physically the needed angle sensitivity is changed from ìradians for direct mechanical movement of the analyzer crystal to milliradian control for movement the XRP angle. In addition to using an XRP for the traditional DEI acquisition method of two scans on opposite sides of the rocking curve preliminary tests will be presented showing the potential of using an XRP to scan quickly through the entire rocking curve. This has the benefit of collecting all the required data for image reconstruction in a single fast measurement thus removing the occurrence of motion artifacts for each point or line used during a scan. The XRP design is also intended to be compatible with combined imaging systems where more than one technique is used to investigate a sample. Candidates for complimentary techniques are investigated and measurements from a combined X-ray imaging system are presented.

This research was inspired by a need to discover more refined technologies for imaging growing joints to facilitate research in childhood arthritis, which is among the most common chronic conditions of childhood. The objective of this project was to develop and test a new technology for imaging growing joints using diffraction enhanced imaging (DEI) combined with computed tomography (CT) using a synchrotron radiation source. DEI is a modality that derives contrast from x-ray refraction, extinction (an extreme form of scatter rejection), and absorption (as in conventional radiography). The ability to add to an image’s contrast from the refraction of x-rays, rather than that solely from absorption, generates more detailed visualization of soft tissue and of interfaces between tissues. Additionally, refraction-based imaging allows reduction of absorbed radiation dose by the sample tissue. For this research, stifle joints from four-week piglet joints were imaged by DEI-CT using the BioMedical Imaging and Therapy (BMIT) beamline at the Canadian Light Source (CLS) synchrotron facility. This new modality for imaging growing joints incorporated a novel feedback control to maintain precise alignment of the analyzer crystal, which is used to re- diffract the beam that passes through the object, throughout the scanning procedure. Results showed that high-resolution DEI-CT provided three-dimensional images of the bone and soft tissue of growing joints at a resolution on the order of microns. Fine detail within and between all joint structures and tissues, including striking detail of cartilage vasculature, a iii characteristic of growing but not mature joints, was demonstrated. This report documents for the first time that DEI combined with CT and using a synchrotron radiation source can generate more detailed images of intact, growing joints than is currently available from conventional imaging modalities. The development of this high resolution imaging system, which provides excellent contrast for both hard and soft tissues, fills an important gap in the suite of imaging modalities available for joint research, particularly during growth.