Exploration of utility of combined optical photothermal infrared and Raman imaging for investigating the chemical composition of microcalcifications in breast cancer

Microcalcifications play an important role in cancer detection. They are evaluated by their radiological and histological characteristics but it is challenging to find a link between their morphology, their composition and the nature of a specific type of breast lesion. Whilst there are some mammographic features that are either typically benign or typically malignant often the appearances are indeterminate. Here, we explore a large range of vibrational spectroscopic and multiphoton imaging techniques in order to gain more information about the composition of the microcalcifications. For the first time, we validated the presence of carbonate ions in the microcalcifications by O-PTIR and Raman spectroscopy at the same time, the same location and the same high resolution (0.5 mu m). Furthermore, the use of multiphoton imaging allowed us to create stimulated Raman histology (SRH) images which mimic histological images with all chemical information. In conclusion, we established a protocol for efficiently analysing the microcalcifications by iteratively refining the area of interest.

Automated summary

Microcalcifications play a key role in cancer detection, but linking their morphology, composition, and the nature of a specific breast lesion is challenging. By utilizing vibrational spectroscopy and multiphoton imaging techniques, we explored the composition of microcalcifications in depth. Through O-PTIR and Raman spectroscopy, we confirmed the presence of carbonate ions in microcalcifications for the first time, and multiphoton imaging allowed us to create stimulated Raman histology (SRH) images that provide chemical information similar to histological images. In conclusion, we established an efficient protocol for analyzing microcalcifications through iterative refinement of the area of interest.