Utilization of Raman spectroscopy to identify breast cancer from the water content in surgical samples containing blue dye

Abstract

Breast conserving surgery (BCS) for breast cancer aims for optimal oncological results with minimal tissue excision. Positive margins due to insufficient resection results in significant numbers of patients requiring re‐excision, which could be resolved with intra‐operative margin analysis (IMA). High wavenumber (HWN) Raman Spectroscopy (RS) examines the difference in protein/lipid environment and water content in tissues. Fluorescence from haemoglobin and blue dye surgical pigments (commonly present in excised breast tissue) can confound HWN RS. We present a Raman system with 785 nm excitation laser and indium gallium arsenide camera capable of quantifying changes in water content in different environments (protein‐rich and lipid‐rich) by measuring the water/total area ratio (W/TAR) of the HWN spectrum. We demonstrate that haemoglobin and blue dye do not adversely affect water content analysis by the W/TAR calculation. Measurement of paired tumour/non‐tumour human breast tissue specimens showed the biochemical differences between tissues, and spectral analysis with W/TAR demonstrated large differences in water content and that our Raman system can accurately differentiate between tumour and non‐tumour tissue, even in the presence of surgical pigments. This provides proof of principle that this Raman system is suitable for further investigation with a view to providing IMA in the clinical environment.