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We report on the design and realization of an x-ray imaging system for quantitative phase-contrast microscopy at high x-ray energy with laboratory-scale instrumentation. Phase and amplitude were separated quantitatively at x-ray energies up to 80 keV with micrometric spatial resolution. The accuracy of the results was tested against numerical simulations, and the spatial resolution was experimentally quantified by measuring a Siemens star phase object. This simple setup should find broad application in those areas of x-ray imaging where high energy and spatial resolution are simultaneously required and in those difficult cases where the sample contains materials with similar x-ray absorption.

We report on what are believed to be the first full-scale images obtained with the coded aperture concept, which uses conventional x-ray sources without the need to collimate/aperture their output. We discuss the differences in the underpinning physical principles with respect to other methods, and explain why these might lead to a more efficient use of the source. In particular, we discuss how the evaluation of the first imaging system provided promising indications on the method’s potential to detect details invisible to conventional absorption methods, use an increased average x-ray energy, and reduce exposure times—all important aspects with regards to real-world implementations.

This paper presents preliminary work aimed at assessing the feasibility of K-edge subtraction imaging using the spectroscopic information provided by a pixellated energy-resolving Cadmium Zinc Telluride detector, having an active area of 20×20 pixels 250 m in size. Images of a test object containing different amounts of Iodine-based contrast agent were formed above and below the K-edge of Iodine (33.2 keV) by integrating, pixel by pixel, different windows of the spectrum. The results show that the optimum integration window for details 1-2 mm in diameter is between 2 keV and 5 keV. Concentrations of down to 50 g Iodine/ml were detected in a 1-mm diameter tube with an entrance dose of 100 Gy.

X-ray phase contrast imaging is a very promising technique that may lead to significant advancements in a variety of fields, perhaps most notably, medical imaging. The radiation physics group at University College London is currently developing an x-ray phase contrast imaging technique that works with laboratory x-ray sources. This system essentially measures the degree to which photons are refracted by regions of an imaged object. The amount of refraction that may be expected to be encountered in practice impacts strongly upon the design of the imaging system. In this paper, we derive an approximate expression between the properties of archetypal imaged objects encountered in practice and the resulting distribution of refracted photons. This is used to derive constraints governing the design of the system.

Scattered radiation in medicine is usually regarded as a problem. It either degrades image contrast or increases absorbed dose. However, if monitored correctly it can provide additional information in diagnostic procedures. It is shown that both coherent and incoherent scattering have a useful role to play. Incoherent or Compton scattering can be used to estimate the density of internal structures. In the study of osteoporosis it has been shown that Compton scatter densitometry leads to better estimates of trabecular bone density than dual-energy absorptiometry. Coherent scattering leads to diffraction effects. These have been used in the study of both archeological and clinical osteoporosis and have been shown to have greater precision than currently accepted procedures. However, the greatest impact for coherent scattering techniques is in the study of breast cancer. Tumour detection can be significantly increased. Copyright © 1999 John Wiley & Sons, Ltd.

Disc degeneration quantification is important for monitoring the effects of new therapeutic methods, such as cell and growth factor therapy. Magnetic resonance (MR) image texture reflects biochemical and structural tissue properties and has been used for differentiating between normal and pathological status in a variety of medical applications.

This book presents an up-to-date view of selected topics on medical imaging. Each chapter is written by an expert in the field and the topics that are selected are all of current interest.The first two chapters deal with the problem of image reconstruction. Chapter 1 considers 3-D volume reconstruction from projection data and Chapter 2 looks at direct Fourier methods in NMR tomography.

After a brief historical introduction to computed tomography, the chapters of this book deal with equipment, the image and its information content, and a collection of CT applications that include other imaging modalities. The author states that the book is intended to be read by physicians, physicists, engineers and technologists who have an interest in, or work with, CT. With such a wide proposed readership the text naturally loses some coherence and consistency in the depth to which material is treated, with the result that it gives too little information in certain areas or intricate detail in others.