Depth-sensitive Raman spectroscopy combined with optical coherence tomography for layered tissue analysis.
Complete characterization of a layered tissue requires probing both the biochemical and the morphological information from its different layers at various depths. We report the development of a combined Raman spectroscopy (RS) and optical coherence tomography (OCT) system that is capable of measuring depth-sensitive Raman signal from the tissue layers imaged by the OCT. The sample arm of a real-time time-domain OCT system was modified to allow for co-alignment of the OCT with the Raman probe beam. The depth sensitivity of Raman was obtained by incorporating confocal Raman configuration that minimized out-of-focus Raman scattered light. The system was first validated using a layered phantom prepared by depositing a thin layer of paraffin over acetaminophen. A good correlation was observed between the OCT images and the Raman signal. The system was also used to record OCT and Raman images of a resected mucosal tissue sample. While OCT image showed the presence of epithelial and stromal layers, Raman spectra measured from these layers confirmed the biochemical difference between the two.
Laser Biomedical Applications and Instrumentation Division, Raja Ramanna Centre for Advanced Technology, R & D Block-D, Indore 452 013, India.
Khan M
KM
Khan
Hemant
H
Krishna
Shovan K
SK
Majumder
K Divakar
KD
Rao
Pradeep K
PK
Gupta
D000082:Acetaminophen; D003238:Connective Tissue; D004848:Epithelium; D006801:Humans; D010232:Paraffin; D019047:Phantoms, Imaging; D013059:Spectrum Analysis, Raman / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*
D000082:Acetaminophen; D010232:Paraffin
FWHM; NA; combined RS-OCT; depth-sensitive Raman spectra