Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

Figure 5

Decay of silicon wafer’s characteristic peak and increase of intralipid’s one characteristic peak while the distance between the silicon wafer and the probe end tip increases in the phantom measurement as shown in Figure 3. The laser power was fixed to 28.7 mW. Notice that from full contact to 100 μm separation, the Raman characteristic peak of the silicon increases and it might happen in the combination of the mismatch of refractive indices between intralipid, silicon wafer, and the probe and the effect of the plano-convex lens in front of the excitation and detection fibers. Mixture of characteristic peaks of the silicon and intralipid still exists till the distance of 800 μm, and it implies that when measuring highly scattering medium in near-infrared (NIR) range such as the biological tissues, the working distance of the probe would be longer than the one described in the specification.

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