Discriminating Model Microcalcifications Immersed and Under Varying Depths of Wax Using Deep Low-Frequency Raman Spectroscopy

Breast microcalcifications are crucial clinical features for breast cancer that remain poorly understood with many present contradicting findings and views. Prior research, which utilized Raman spectroscopy (RS), only focused on the mid-frequency spectral region. In this work, we applied low-frequency RS to three experimental setups, with synthetic calcium oxalate and hydroxyapatite in amorphous and crystalline forms immersed and under varying depths of paraffin wax. When comparing the full spectra at all offsets for the three experimental setups, we found that the defocused microspatially offset setup performed the best with an area under the curve (AUC) of 0.87. Furthermore, it was found that the low-frequency spectral region was optimal for this setup with an AUC of 0.94. Overall, the low-frequency region outperformed the mid-frequency spectral regions for two out of the three experimental setups with the AUC improving by up to 13% from 0.81 to 0.94. This is attributed to the low-frequency Raman region containing order information of the probed solids allowing the amorphous and crystalline forms to be more accurately classified.