Quantifying the Sensitivity in X-Ray Diffraction Measurements in Thick Tissue Samples

Abstract

Previous studies have shown different tissue types and manifestations of diseases result in different X-ray diffraction (XRD) signatures. Earlier efforts by our group have demonstrated the uses and benefits of XRD imaging of thin tissue samples; however, additional questions remain about the ability for XRD-based tissue analysis to provide useful and quantitative data for thicker samples. Thicker samples, up to several centimeters, are representative of real diagnostic scenarios and freshly excised biospecimens in need of further analysis. The goal of our new experimental set-up is to demonstrate that there is a useful signal in XRD imaging that can be extracted from a target composed of thicker materials. My testbed system uses a pencil beam and a Kromek D-matrix detector. This detector has a 2D array, which allows for energy independent and angle dispersive XRD measurements with a very short acquisition time. This study utilizes biologically-relevant phantoms to quantify detection limits in terms of signal-to-noise. Theoretical calculations using Beer’s law are compared to my experimental measurements. The results show the impact of self-attenuation and scatter on signal strength for narrow (10 mm x 10 mm) and wide (50 mm x 50 mm) phantom of varying thicknesses. Ultimately, this new system will provide the quantitative and experimental results to support future studies on in-vivo and ex-vivo XRD diagnostic techniques in the medical community.