  Conventional haematoxylin, eosin and saffron (HES) histopathology, currently
the gold-standard for pathological diagnosis of cancer, requires extensive
sample preparations that are achieved within time scales that are not
compatible with intra-operative situations where quick decisions must be taken.
Providing to pathologists a close to real-time technology revealing tissue
structures at the cellular level with HES histologic quality would provide an
invaluable tool for surgery guidance with evident clinical benefit. Here, we
specifically develop a stimulated Raman imaging based framework that
demonstrates gastro-intestinal (GI) cancer detection of unprocessed human
surgical specimens. The generated stimulated Raman histology (SRH) images
combine chemical and collagen information to mimic conventional HES
histopathology staining. We report excellent agreements between SRH and HES
images acquire on the same patients for healthy, pre-cancerous and cancerous
colon and pancreas tissue sections. We also develop a novel fast SRH imaging
modality that captures at the pixel level all the information necessary to
provide instantaneous SRH images. These developments pave the way for
instantaneous label free GI histology in an intra-operative context.
