Based on compelling epidemiologic and corroboratory in vitro studies, carotenoids are thought to
have great potential as dietary prevention against cancer. Yet, carotenoid-based chemopreventive trials
have found very contradictory results. Definitive conclusions from these trials are hampered by an
inability to accurately and safely measure carotenoids in specific tissues at risk of cancer development.
Raman spectroscopy has been proposed as an optical technology with which to analyze various molecules
in live tissues. One major obstacle that impedes the clinical use of this powerful technology is
the lack of a fiberoptic Raman probe suitable for endoscopic tissue evaluation. A single-fiber resonance
Raman Spectroscope capable of noninvasive “optical biopsies” to measure carotenoid concentrations
in live tissues has been developed. The accuracy of this Raman instrument was confirmed by
comparison with more standard methods of spectrophotometry and high-pressure liquid chromatography
using solubilized β-carotene (BC) and BC-loaded cells before use in a small patient cohort. This
Raman instrument detected intact BC as well as BC oxidative breakdown as a decrement of its Raman
signal in cells. Use of the Raman instrument in our small cohort study showed its feasibility for measuring
human tissues and raised some potentially intriguing possibilities about BC tissue pharmacokinetics
and oxidative biology. Based on these results, our newly developed single fiberoptic resonance
Raman instrument may provide a very useful method of measuring carotenoids and their oxidative
breakdown within live tissue during future carotenoid chemopreventive trials. This proof-of-concept
study provides the foundation to justify future validation of our Raman prototype