Design, Optimization, and Testing of a Combined Tri-Axial Polarized Energy Dispersive X-Ray Fluorescence and Energy Dispersive X-Ray Diffraction System for Biological Sample Classification

Abstract

The examination of biological samples yields information regarding the function and structure of the sample tissue. Many non-destructive methods are employed to interrogate biological samples, helping to further our understanding of these complex systems.

A combined Polarized Energy Dispersive X-Ray Fluorescence and Energy Dispersive X-Ray Diffraction system was designed, tested, and optimized for the purpose of classifying biological samples. This system is capable of determining the elemental composition and structural components present within a biological sample. Using two energy dispersive techniques allowed for decreased data acquisition times, and a single x-ray source to be used by both setups.

The system was optimized to improve its performance when measuring biological samples. The x-ray fluorescence spectrometer uses metallic secondary targets that allow for low minimum detection limits in transition metals, which are usually very important to biological tissue function. The x-ray diffraction spectrometer was also optimized to examine structures commonly found in biological samples, while still providing an adjustable range of measurable momentum transfers. Other optimizations performed on both systems provided significant improvements when measuring biological samples.

The functionality of the combined system was tested by measuring several sets of tissue samples. Two sets of cancerous breast tissues, were examined to determine measurable differences between healthy and abnormal tissue. A set of rat organs overloaded with iron were also measured to examine the high customizability and sensitivity of the x-ray fluorescence spectrometer. Lastly, a series of calibration samples were measured to determine minimum detection limits of commonly found elements. All measurements agreed with published literature, and the combined spectrometers showed an improvement in both accuracy and speed over other available spectrometers when measuring biological samples.