Probe pressure effects on human skin diffuse reflectance and fluorescence spectroscopy measurements

摘要

Abstract. Diffuse reflectance and fluorescence spectroscopy are popular research techniques for noninvasivendisease diagnostics. Most systems include an optical fiber probe that transmits and collects optical spectra inncontact with the suspected lesion. The purpose of this study is to investigate probe pressure effects on human skinnspectroscopicmeasurements.We conduct an in-vivo experiment on human skin tissue to study the short-term(<2s)nand long-term (>30 s) effects of probe pressure on diffuse reflectance and fluorescence measurements. Short-termnlight probe pressure (P0 < 9mN/mm2) effects are within 0 ± 10% on all physiological properties extractednfrom diffuse reflectance and fluorescence measurements, and less than 0 ± 5% for diagnostically significantnphysiological properties. Absorption decreases with site-specific variations due to blood being compressed outnof the sampled volume. Reduced scattering coefficient variation is site specific. Intrinsic fluorescence shows anlarge standard error, although no specific pressure-related trend is observed. Differences in tissue structure andnmorphology contribute to site-specific probe pressure effects. Therefore, the effects of pressure can be minimizednwhen the pressure is small and applied for a short amount of time; however, long-term and large pressures inducensignificant distortions in measured spectra. C u00022011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3525288]