TITLE : Spatially offset Raman spectroscopy for surgical margin evaluation during breast conserving therapy

The risk of local recurrence for breast cancers is strongly correlated with the presence of a tumorwithin 1 to 2 mm of the surgical margin on the excised specimen. Previous experimental and theoretical resultssuggest that spatially offset Raman spectroscopy (SORS) holds much promise for intraoperative margin analysis.Based on simulation predictions for signal-to-noise ratio differences among varying spatial offsets, a SORS probewith multiple source-detector offsets was designed and tested. It was then employed to acquire spectra from 35frozen–thawed breast tissue samples in vitro. Spectra from each detector ring were averaged to create a compositespectrum with biochemical information covering the entire range from the tissue surface to ∼2 mm below thesurface, and a probabilistic classification scheme was used to classify these composite spectra as “negative” or“positive” margins. This discrimination was performed with 95% sensitivity and 100% specificity, or with 100%positive predictive value and 94% negative predictive value. C©2011 Society of Photo-Optical Instrumentation Engineers (SPIE).[DOI: 10.1117/1.3600708]