Article

Multiple-Fiber Probe Design for Fluorescence Spectroscopy in Tissue

Harvard University, Cambridge, Massachusetts, United States
Applied Optics (Impact Factor: 1.78). 09/2002; 41(22):4712-21. DOI: 10.1364/AO.41.004712
Source: PubMed

ABSTRACT The fiber-optic probe is an essential component of many quantitative fluorescence spectroscopy systems, enabling delivery of excitation light and collection of remitted fluorescence in a wide variety of clinical and laboratory situations. However, there is little information available on the role of illumination--collection geometry to guide the design of these components. Therefore we used a Monte Carlo model to investigate the effect of multifiber probe design parameters--numerical aperture, fiber diameter, source--collection fiber separation distance, and fiber-tissue spacer thickness--on light propagation and the origin of detected fluorescence. An excitation wavelength of 400 nm and an emission wavelength of 630 nm were simulated. Noteworthy effects included an increase in axial selectivity with decreasing fiber size and a transition with increasing fiber-tissue spacer size from a subsurface peak in fluorophore sensitivity to a nearly monotonic decrease typical of single-fiber probes. We provide theoretical evidence that probe design strongly affects tissue interrogation. Therefore application-specific customization of probe design may lead to improvements in the efficacy of fluorescence-based diagnostic devices.

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    • "Fluorescence measurements are non-destructive, fast, and less expensive in instrumentation. Recently the fluorescence technique was used to investigate biological materials (Kim et al., 2003; Pfefer et al., 2002), detect environmental, chemical, and biological stresses in plants (Gavel and Marsalek, 2004; Kim et al., 2001) and monitor food quality and safety (Kong et al., 2004; Vargas et al., 2004). Chlorophyll fluorescence has been researched for measuring fruit postharvest quality and condition such as defects and ripeness (Bodria et al., 2002; Mir et al., 2001). "
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