Influence of illumination-collection geometry on fluorescence spectroscopy in multilayer tissue
Device-tissue interface geometry influences both the intensity of detected fluorescence and the extent of tissue sampled. Previous modelling studies have often investigated fluorescent light propagation using generalised tissue and illumination-collection geometries. However, the implementation of approaches that incorporate a greater degree of realism may provide more accurate estimates of light propagation. In this study, Monte Carlo modelling was performed to predict how illumination-collection parameters affect signal detection in multilayer tissue. Using the geometry and optical properties of normal and atherosclerotic aortas, results for realistic probe designs and a semi-infinite source-detection scheme were generated and compared. As illumination-collection parameters, including single-fibre probe diameter and fibre separation distance in multifibre probes, were varied, the signal origin deviated significantly from that predicted using the semi-infinite geometry. The semi-infinite case under-predicted the fraction of fluorescence originating from the superficial layer by up to 23% for a 0.2 mm diameter single-fibre probe and over-predicted by 10% for a multifibre probe. These results demonstrate the importance of specifying realistic illumination-collection parameters in theoretical studies and indicate that targeting of specific tissue regions may be achievable through customisation of the illumination-collection interface. The device- and tissue-specific approach presented has the potential to facilitate the optimisation of minimally invasive optical systems for a wide variety of applications.
KeywordsFibre-optic probe Fluorescence spectroscopy Light-tissue interaction Monte Carlo modelling Optical diagnostics
Unable to display preview. Download preview PDF.
- Arakawa, K., Isoda, K., Ito, T., Nakajima, K., Shibuya, T., andOhsuzu, F. (2002): ‘Fluorescence analysis of biochemical constituents identifies atherosclerotic plaque with a thin fibrous cap’,Arterioscler. Thromb. Vasc. Biol.,22, pp. 1002–1007Google Scholar
- Avrillier, S., Tinet, E., Ettori, D., Tualle, J. M., andGelebart, B. (1998): ‘Influence of the emission-reception geometry in laser-induced fluorescence spectra from turbid media’,Appl. Opt.,37, pp. 2781–2787Google Scholar
- DaCosta, R. S., Lilge, L. D., Kost, J., Cirroco, M., Hassaram, S., Marcon, N., andWilson, B. C. (1997). ‘Confocal fluorescence microscopy, microspectrofluorimetry, and modeling studies of laser-induced fluorescence endoscopy (LIFE) of human colon tissue’,Proc. SPIE,2975, pp. 98–107Google Scholar
- Gmitro, A. F., Cutruzzola, F. W., Stetz, M. L., andDeckelbaum, L. I. (1988): ‘Measurement depth of laser-induced fluorescence with application to laser angioplasty’,Appl. Opt.,27, pp. 1844–1849Google Scholar
- Jacques, S. L., andWang, L. (1995): ‘Monte Carlo modeling of light transport in tissues’, inWelch, A. J., andvan Gemert, A. J. (Eds): ‘Optical-thermal response of laser-irradiated tissue’ (Plenum Press, New York, 1995)Google Scholar
- Keijzer, M., Richards-Kortum, R. R., Jacques, S. L., andFeld, M. S. (1989): ‘Fluorescence spectroscopy of turbid media: auto-fluorescence of the human aorta’,Appl. Opt.,28, pp. 4286–4292Google Scholar
- Pfefer, T. J., Schomacker, K. T., Ediger, M. N., andNishioka, N. S. (2001): ‘Light propagation in tissue during fluorescence spectroscopy with single-fiber probes’,IEEE J. Sel. Top. Quant. Elect.,7, pp. 1004–1012Google Scholar
- Pfefer, T. J., Schomacker, K. T., Ediger, M. N., andNishioka, N. S. (2002): ‘Multiple-fiber probe design for fluorescence spectroscopy in tissue’,Appl. Opt.,41, pp. 4712–4721Google Scholar
- Pfefer, T. J., Matchette, L. S., Ross, A. M., andEdiger, M. N. (2003): ‘Selective detection of fluorophore layers in turbid media: the role of fiberoptic probe design’,Opt. Lett.,28, pp. 120–122Google Scholar
- Quan, L., andRamanujam, N. (2002): ‘Relationship between depth of a target in a turbid medium and fluorescence measured by a variable-aperture method’,Opt. Lett.,27, pp. 104–106Google Scholar
- Richards-Kortum, R. (1995). ‘Fluorescence spectroscopy of turbid media’, inWelch, A. J., andvan Gemert, M. J. C. (Eds): ‘Optical-thermal response of laser-irradiated tissue’ (Plenum Press, 1995)Google Scholar
- Zonios, G. I., Cothren, R. M., Arendt, J. T., Wu, J., Van Dam, J., Crawford, J. M., Manoharan, R., andFeld, M. S. (1996): ‘Morphological model of human colon tissue fluorescence’,IEEE Trans. Biomed. Eng.,43, pp. 113–122Google Scholar