Ultra-low spatial resolution Raman mapping using a novel fibre optic probe

Ultra-low spatial resolution Raman (ULSRR) mapping using fibre probes has been performed on mammalian and human tissues. This will provide an understanding of the potential for in vivo surveillance of the lining of organs using such a technique and for identifying abnormal tissues such as residual tumours within a surgical field. The aim of the study was to create Raman probe map images of excised oesophageal specimens following radical and palliative oesophagectomy procedures. A reproducible mapping grid was placed over the excised tissue surface and Raman mapping at 830nm performed at regular intervals to provide images of 200 pixels over the region of interest. Principal component analysis was used to create pseudocolour score images of both porcine phantoms and a human resected oesophagus. A principal component fed linear discriminant (LD) classification model of 72 biopsy samples from 35 patients was created using a novel single fibre Raman probe. A subset of the training dataset was used to populate a matrix of 200 pixels to simulate a Raman probe map. Spectra from the simulated map were then projected onto the LD model and a pseudocolour LD pathology map created. Delineation of clinically significant pathology groups was demonstrated therefore this study has shown the feasibility of in vivo ULSRR for margin assessment using a Raman probe.