The aim of the present study is to evaluate the capability of a miniaturized Raman endoscope (mRE) system to monitor the advancement of colorectal tumors in model mice as a method that is noninvasive to the tumor itself. Nevertheless, the endoscope is narrow enough to observe the inside of the mouse colon in such a way that is semi-noninvasive to the animal. However, the mRE system allowed the visualization and Raman spectral measurement of any targeted point within the colorectal tumor in model mice under anesthesia, without damaging the tissue (i.e., noninvasively). Continuous monitoring of the same tumor allowed the observation of alterations in its molecular composition and size, along with its advancement. The tumor lesion was discriminated from normal tissues of the control mouse with an accuracy of 86.8%. We succeeded in visualizing and performing Raman spectral observations on a shrinking polyp type tumor. The Raman analysis suggested that it was not cured but supposedly transformed to another tumor type.

要旨 臨床で実用的に利用できる分光診断技術，すなわち光バイオプシー技術を実現する為には，光ファイバーを利用し た in situ 計測が実現できる必要がある．現在の分光計測技術の中で，光ファイバー計測への応用が可能で，かつ高い 分析能力を持つものがラマン分光分析技術である． しかし， ラマン分光分析技術はイメージ計測への応用が困難であり， 病理検査などの形態観測がゴールドスタンダードである臨床医学において有効な技術とするためには，自家蛍光ハイ パースペクトルイメージなどの新しい技術との併用が必要である．本稿ではラマン分光分析を基礎とした光バイオプ シー技術の展望を議論する． キーワード：ラマン分光，光バイオプシー，がん診断，無標識画像化，無・低侵襲 AbstractAn optical biopsy technique based on optical spectroscopy attracts keen interest of clinicians. The instrument for the optical biopsy needs to have optical fiber probes for in situ measurement in the body. Raman spectroscopy which is suitable for fiber optic applications has high potential in analysis of biological materials. On the other hand, it is difficult to extend Raman spectroscopy into image application. It needs supporting new techniques such as autofluorescence hyper-spectral image to process the Raman data more familiar and useful for the clinicians. The present manuscript discusses prospect and potential of Raman spectroscopy in the practical clinical use.