Side‐Viewing Endoscopic Raman Spectroscopy for Angle‐Resolved Analysis of Luminal Organs

Abstract

AbstractThere are many medical applications requiring angle‐resolved analysis of luminal organs. One example is lung cancer detection. Early diagnosis is the most effective way to tackle this disease. This, however, remains a challenge due to the lack of accurate detection technology. The problem is exacerbated in cases of peripheral lung cancer growing on narrow bronchi that are difficult to probe. Here, an endoscopic Raman spectroscopy device is demonstrated with a side‐viewing functionality that enables circumferential scanning spectral measurements inside thin conduits. A tubular micro rotary stepping actuator is custom‐designed and integrated with a Raman probe, for the first time, to scan a probing laser beam sideways for angle‐resolved local Raman analysis with no aid of tissue labeling, toward enabling detection of lesion‐induced biochemical changes in vivo and in real time. A microfabricated prototype is evaluated using test chemicals, harvested animal lung tissue ex vivo, as well as a murine colon model in situ and human skin in vivo. All the test results show excellent agreements with reported reference data while revealing >99% wavenumber accuracies. The study indicates that microactuator‐assisted endoscopic Raman spectroscopy is a promising technology for luminal tissue analysis and encourages further studies of its sensitivity in lesion detection.