Quantitative X-ray Phase Contrast Imaging

1) Brief description of the context of the research including potential impact

X-rays are unique for investigating bulky and opaque samples, as their broad use in medicine, security and non-destructive inspection demonstrates. X-ray phase contrast imaging (XPCI) methods overcome the limitations of conventional radiography, especially for those samples exhibiting low absorption. Biological soft matter is mostly composed of low-Z elements, which do not absorb X-rays with high probability, but the capability of detecting phase distortions in the X-ray wavefront enables visualising details that would be otherwise X-ray-invisible.

The Advanced X-ray Imaging Group (AXIm) has pioneered the development of compact XPCI systems, and a partnership with Nikon has built a first prototype, field deployed for intraoperative imaging of breast tissue. The image quality was vastly superior to the current clinical standards, however the interpretation of images remained largely qualitative and highly subject-dependent.

Calibration and uncertainty evaluation are fundamental elements of instrument traceability and the National Physical Laboratory NPL is leading the development of X-ray CT for dimensional metrology at national and international levels. The creation of a metrology framework for XPCI micro-CT applied in the medical field would be a step change in the efforts to transform three-dimensional images into absolute measurements, where the instrument's bias, precision, and accuracy are known and characterised.

2) Aims and Objectives

The project aims at developing models and techniques to merge the most advanced X-ray imaging techniques, providing unique sensitivity for soft-tissues and more in general low-Z materials, with a fully quantitative and traceable measurement methodology. Absolutely quantitative measurements will make possible, and meaningful, the comparison of samples across different experiments, different labs, and different points in time, shifting the way researchers, clinicians and developers look at specimens. These new approaches would provide a pathway for transforming X-ray micro-CT applications across a wide spectrum of applications, encompassing three-dimensional imaging of tissue in clinical applications, design and manufacturing and pre-clinical small-animal investigations.

3) Novelty of Research Methodology

Calibration and uncertainty evaluation are fundamental elements of instrument traceability and the National Physical Laboratory NPL is leading the development of X-ray CT for dimensional metrology at national and international levels. The creation of a metrology framework for XPCI micro-CT applied in the medical field would be a step change in the efforts to transform three-dimensional images into absolute measurements, where the instrument's bias, precision, and accuracy are known and characterised.

4) Alignment to EPSRC's strategies and research areas

This program aligns well with the EPSRC research areas of light matter interaction, medical imaging and sensors and instrumentation; contributing to the strategic priorities of frontiers in engineering and technology, ai and transforming health and healthcare.

5) Any companies or collaborators involved

This project will merge unique and UCL proprietary XPCI technology, state-of-the-art metrology know-how of NPL and the expertise of industrial partner Nikon. We believe this will provide a terrific platform for a PhD program, where the student will learn the fundamental physics within an excellent Academic research environment, they will work in close collaboration with world-leading experts within the NPL and will also be exposed to industry with hands-on experience of commercial exploitation.