Spectral Signatures from Small Angle X-ray Scattering for Breast Cancer Discrimination

The coherent nature of X-ray scattering at small angles produce scattering interference which generates a unique energy spectrum characteristic of the intra-molecular structure of the irradiated sample. The phase difference introduced by the scattering centers will depend upon the wavelength of the radiation and the scattering angle. The resulting interference effects can be studied very effectively using a mono energetic source and scanning an angular range. However, when using a poly energetic source the interference happen at different energies simultaneously, which generates a much more complex and obscured interference pattern due to the spread of wavelength. The spectral pattern still contains valuable information about the electron density distribution of materials of interest. In this study we propose the use of spectral x-ray measurements with an advanced photon counting detector Timepix3 (300 mu m Si) as well as an X-123 (1mm CdTe) Amptek spectrometer to measure the small angle x-ray scattering generated by samples illuminated by a polychromatic X-ray source. We show that the resultant scatter interference can be effectively characterized with this setting. In this study, we also examine the photon counting profiles obtained from different metals and plastics as well as normal and malignant breast tissue. The measured photon counting spectrum for different materials shows reproducible features. We were able to characterize benign and malignant breast tissue using spectral scatter signature. Momentum transfer when scattered from benign breast tissue is observed to be lower in comparison to that from carcinoma. These features could be used for reliable tissue discrimination and material identification. Future work will assess the potential and limitations of this method in improving mammographic diagnostic capabilities.