Optical Imaging with Signal Processing for Non-invasive Diagnosis in Gastric Cancer: Nonlinear Optical Microscopy Modalities

Gastric cancer or stomach cancer has high incident rate and the leading cause of mortality worldwide. GC is usually undetected and asymptotic till the advanced chronic stages of its progression. Despite much advancement of technologies, still diagnosis is poor. This makes GC a fatal chronic disease. Over two decades of advancement in nonlinear optical (NLO) microscopy, it has become a powerful tool for laser-based imaging of tissue. Each of NLO modality is sensitive for specific molecule or structure. This may be useful for the understanding of the complex biological system in cancer detection. Here, we will discuss label-free, non-invasive endoscopy-based methods for morphological imaging by combining coherent anti-Stokes Raman scattering (CARS), Two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) methods of NLO microscopy.