(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose: Although mammography is the gold standard for early screening for breast cancer, there is a need in improving its specificity. X-ray diffraction (XRD) has shown the ability to detect cancer based on its molecular properties; however, most commercial XRD systems focus on very thin targets using very low x-ray energies. To improve the imaging capabilities for thicker targets, we have developed XRD imaging systems capable of running at diagnostic X-ray energies. In this work, we evaluate the performance of our XRD system at two source configurations: 20 keV (mammography) and 60 keV (radiography).
Methods: An XRD system was built using a Bremsstrahlung X-ray source, an energy discriminating X-ray detector, and customizable geometry. XRD scans were performed using adipose, fibroglandular, and carcinoma surrogate targets at two mean energies – 20 keV and 60 keV. The low energy configuration used a molybdenum filter and 2-mm collimated beam, whereas the high energy configuration used a 1-mm diameter X-ray beam. Each target was scanned 5-10 times to evaluate measurement uncertainty. XRD spectra, normalized to mAs, were extracted from the detected signal and compared against known diffraction data for each material. System performance was evaluated using signal-to-noise ratio (SNR), root-mean-squared error (RMSE), and uncertainty in each measurement.
Results: The 20 keV configuration showed 5.7 SNR, 4.9% RMSE, and 4% uncertainty. The 60 keV configuration showed 4.9 SNR, 5.4% RMSE, and 3% uncertainty. Overall, the 20 keV configuration showed 24% improvement in SNR compared to the 60 keV configuration.
Conclusion: We demonstrated the viability of low-energy XRD imaging for characterizing breast tissues. The low energy configuration presents a viable method to characterize breast tissues at energies relevant to mammography, representing a potential method to improve specificity in mammography.
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