Multi-modal endoscopy: OCT and fluorescence

Optical Coherence Tomography (OCT) is a recently developed and still fast evolving biomedical imaging modality based on the technique of low-coherence interferometry. OCT fills the gap between the scales of high-frequency ultrasound and confocal microscopy with an axial resolution from 1 to 15 um. OCT imaging contrast relies on tissue morphology and is governed by tissue optical absorption and scattering, and intrinsically OCT carries little molecular information. In contrast, fluorescence imaging is well known for providing tissue biochemical or molecular information. The concept of combing of OCT and fluorescence imaging has been attractive due to the fact that OCT and fluorescence imaging are complementary. Thus, in this chapter we will discuss the potential of combining OCT and single- or multi-photon fluorescence imaging endoscopically with an emphasis on system and probe design.