Abstract

We have applied fluorescence lifetime imaging (FLIM) to the autofluorescence of different kinds of biological tissue in vitro, including animal tissue sections and knee joints as well as human teeth, obtaining two-dimensional maps with functional contrast. We find that fluorescence decay profiles of biological tissue are well described by the stretched exponential function (StrEF), which can represent the complex nature of tissue. The StrEF yields a continuous distribution of fluorescence lifetimes, which can be extracted with an inverse Laplace transformation, and additional information is provided by the width of the distribution. Our experimental results from FLIM microscopy in combination with the StrEF analysis indicate that this technique is ready for clinical deployment, including portability that is through the use of a compact picosecond diode laser as the excitation source. The results obtained with our FLIM endoscope successfully demonstrated the viability of this modality, though they need further optimization. We expect a custom-designed endoscope with optimized illumination and detection efficiencies to provide significantly improved performance.

© 2003 Optical Society of America

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  1. G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).
  2. N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
    [CrossRef] [PubMed]
  3. R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
    [CrossRef] [PubMed]
  4. R. Y. Tsien, M. Poenie, “Fluorescence ratio imaging: a new window into intracellular ionic signalling,” Trends Biochem. Sci. 11, 450–455 (1986).
    [CrossRef]
  5. M. Sinaasappel, H. J. C. M. Sterenborg, “Quantification of the hematoporphyrin derivative by fluorescence measurement using dual-wavelength excitation and dual-wavelength detection,” Appl. Opt. 32, 541–548 (1993).
    [CrossRef] [PubMed]
  6. K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
    [CrossRef]
  7. P. I. H. Bastiaens, A. Squire, “Fluorescence lifetime imaging microscopy: spatial resolution of biochemical processes in the cell,” Trends Cell Biol. 9, 48–52 (1999).
    [CrossRef] [PubMed]
  8. R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
    [CrossRef]
  9. W. Becker, A. Bergmann, G. Weiss, “Lifetime imaging with the Zeiss LSM-510,” in Multiphoton Microscopy in the Biomedical Sciences II, A. Periasamy, W. M. Keck, P. T. C. So, eds., Proc. SPIE4620, 30–35 (2002).
    [CrossRef]
  10. See, for instance, P. C. Schneider, R. M. Clegg, “Rapid acquisition analysis and display of fluorescence lifetime-resolved images for real-time applications,” Rev. Sci. Instrum. 68, 4107–4119 (1997).
    [CrossRef]
  11. See, for instance,G. Valentini, C. D’Andrea, D. Comelli, A. Pifferi, P. Taroni, A. Torricelli, R. Cubbeddu, C. Battaglia, C. Consolandi, G. Salani, L. Rossi-Bernardi, G. De Bellis, “Time-resolved DNA-microarray reading by an intensified CCD for ultimate sensitivity,” Opt. Lett. 25, 1648–1650 (2000).
    [CrossRef]
  12. J. R. Lakowicz, Principles of Fluorescence Spectroscopy (Kluwer, New York, 1999).
    [CrossRef]
  13. K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
    [CrossRef]
  14. H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
    [CrossRef] [PubMed]
  15. J. Y. Qu, J. W. Hua, Z. J. Huang, “Correction of geometrical effects on fluorescence imaging of tissue,” Opt. Commun. 176, 319–326 (2000).
    [CrossRef]
  16. J. Y. Qu, “Real time calibrated fluorescence imaging of tissue in vivo by using the combination of fluorescence and cross-polarized reflection,” in Biomedical Topical Meetings, Vol. 71 of OSA Trends in Optics and Photonics Series (Optical Society of America, Washington, D.C., 2002), pp. 485–487.
  17. H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
    [CrossRef]
  18. T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
    [CrossRef]
  19. Y. S. Sabharwal, A. R. Rouse, L. Donaldson, M. F. Hopkins, A. F. Gmitro, “Slit-scanning confocal microendoscope for high-resolution in vivo imaging,” Appl. Opt. 38, 7133–7144 (1999).
    [CrossRef]
  20. G. J. Tearney, R. H. Webb, B. E. Bouma, “Spectrally encoded confocal microscopy,” Opt. Lett. 23, 1152–1154 (1998).
    [CrossRef]
  21. J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
    [CrossRef]
  22. D. R. James, W. R. Ware, “A fallacy in the interpretation of fluorescence decay parameters,” Chem. Phys. Lett. 120, 455–459 (1985).
    [CrossRef]
  23. J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
    [CrossRef] [PubMed]
  24. J. R. Alcala, “The effect of harmonic conformational trajectories on protein fluorescence and lifetime distributions,” J. Chem. Phys. 101, 4578–4584 (1994).
    [CrossRef]
  25. F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
    [CrossRef]
  26. D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
    [CrossRef]
  27. Spatial image quality is a measure of lifetime variability between connected pixels within regions of the same average lifetime; image contrast measures lifetime variation between averaged regions.
  28. S. W. Provencher, “contin: a general purpose constrained regularization program for inverting noisy linear algebraic and integral equations,” Comput. Phys. Commun. 27, 229–242 (1982).
    [CrossRef]
  29. K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

2002 (1)

2001 (2)

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

2000 (2)

1999 (5)

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

Y. S. Sabharwal, A. R. Rouse, L. Donaldson, M. F. Hopkins, A. F. Gmitro, “Slit-scanning confocal microendoscope for high-resolution in vivo imaging,” Appl. Opt. 38, 7133–7144 (1999).
[CrossRef]

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

P. I. H. Bastiaens, A. Squire, “Fluorescence lifetime imaging microscopy: spatial resolution of biochemical processes in the cell,” Trends Cell Biol. 9, 48–52 (1999).
[CrossRef] [PubMed]

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

1998 (5)

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).

G. J. Tearney, R. H. Webb, B. E. Bouma, “Spectrally encoded confocal microscopy,” Opt. Lett. 23, 1152–1154 (1998).
[CrossRef]

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

1997 (2)

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

See, for instance, P. C. Schneider, R. M. Clegg, “Rapid acquisition analysis and display of fluorescence lifetime-resolved images for real-time applications,” Rev. Sci. Instrum. 68, 4107–4119 (1997).
[CrossRef]

1994 (2)

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

J. R. Alcala, “The effect of harmonic conformational trajectories on protein fluorescence and lifetime distributions,” J. Chem. Phys. 101, 4578–4584 (1994).
[CrossRef]

1993 (1)

1991 (1)

F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
[CrossRef]

1987 (1)

J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
[CrossRef] [PubMed]

1986 (1)

R. Y. Tsien, M. Poenie, “Fluorescence ratio imaging: a new window into intracellular ionic signalling,” Trends Biochem. Sci. 11, 450–455 (1986).
[CrossRef]

1985 (1)

D. R. James, W. R. Ware, “A fallacy in the interpretation of fluorescence decay parameters,” Chem. Phys. Lett. 120, 455–459 (1985).
[CrossRef]

1982 (1)

S. W. Provencher, “contin: a general purpose constrained regularization program for inverting noisy linear algebraic and integral equations,” Comput. Phys. Commun. 27, 229–242 (1982).
[CrossRef]

Ackroyd, R.

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

Alcala, J. R.

J. R. Alcala, “The effect of harmonic conformational trajectories on protein fluorescence and lifetime distributions,” J. Chem. Phys. 101, 4578–4584 (1994).
[CrossRef]

J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
[CrossRef] [PubMed]

Alegría, A.

F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
[CrossRef]

Alvarez, F.

F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
[CrossRef]

Bastiaens, P. I. H.

P. I. H. Bastiaens, A. Squire, “Fluorescence lifetime imaging microscopy: spatial resolution of biochemical processes in the cell,” Trends Cell Biol. 9, 48–52 (1999).
[CrossRef] [PubMed]

Battaglia, C.

Becker, W.

W. Becker, A. Bergmann, G. Weiss, “Lifetime imaging with the Zeiss LSM-510,” in Multiphoton Microscopy in the Biomedical Sciences II, A. Periasamy, W. M. Keck, P. T. C. So, eds., Proc. SPIE4620, 30–35 (2002).
[CrossRef]

Benny Lee, K. C.

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Bergmann, A.

W. Becker, A. Bergmann, G. Weiss, “Lifetime imaging with the Zeiss LSM-510,” in Multiphoton Microscopy in the Biomedical Sciences II, A. Periasamy, W. M. Keck, P. T. C. So, eds., Proc. SPIE4620, 30–35 (2002).
[CrossRef]

Bouma, B. E.

Brown, N.

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

Clegg, R. M.

See, for instance, P. C. Schneider, R. M. Clegg, “Rapid acquisition analysis and display of fluorescence lifetime-resolved images for real-time applications,” Rev. Sci. Instrum. 68, 4107–4119 (1997).
[CrossRef]

Cline, R.

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

Cole, M. J.

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Colmenero, J.

F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
[CrossRef]

Comelli, D.

Consolandi, C.

Cubbeddu, R.

Cubeddu, R.

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Cuschieri, A.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

D’Andrea, C.

Dayel, M. J.

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

De Bellis, G.

Donaldson, L.

Dowling, K.

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

Dymoke-Bradshaw, A. K. L.

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

Elson, D. S.

Erdmann, R.

Forrer, M.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

French, P. M. W.

D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
[CrossRef]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

Gmitro, A. F.

Gratton, E.

J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
[CrossRef] [PubMed]

Guillou, L.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Hares, J. D.

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

Hopkins, M. F.

Hua, J. W.

J. Y. Qu, J. W. Hua, Z. J. Huang, “Correction of geometrical effects on fluorescence imaging of tissue,” Opt. Commun. 176, 319–326 (2000).
[CrossRef]

Huang, Z. J.

J. Y. Qu, J. W. Hua, Z. J. Huang, “Correction of geometrical effects on fluorescence imaging of tissue,” Opt. Commun. 176, 319–326 (2000).
[CrossRef]

Hyde, S. C. W.

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

Ina, H.

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

Jahan, A.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

James, D. R.

D. R. James, W. R. Ware, “A fallacy in the interpretation of fluorescence decay parameters,” Chem. Phys. Lett. 120, 455–459 (1985).
[CrossRef]

Jichlinski, P.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Jones, R.

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Kelty, C.

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

Kitagawa, M.

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

Kucera, P.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Lakowicz, J. R.

J. R. Lakowicz, Principles of Fluorescence Spectroscopy (Kluwer, New York, 1999).
[CrossRef]

Lange, N.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Lauritsen, K.

Lévêque-Fort, S.

D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
[CrossRef]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Lever, M. J.

D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
[CrossRef]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

K. Dowling, M. J. Dayel, M. J. Lever, P. M. W. French, J. D. Hares, A. K. L. Dymoke-Bradshaw, “Fluorescence lifetime imaging with picosecond resolution for biomedical applications,” Opt. Lett. 23, 810–812 (1998).
[CrossRef]

MacAuley, C. E.

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

Marti, A.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

McKechnie, T.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

Mizeret, J.

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

Ohashi, I.

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

Padgett, M.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

Pifferi, A.

See, for instance,G. Valentini, C. D’Andrea, D. Comelli, A. Pifferi, P. Taroni, A. Torricelli, R. Cubbeddu, C. Battaglia, C. Consolandi, G. Salani, L. Rossi-Bernardi, G. De Bellis, “Time-resolved DNA-microarray reading by an intensified CCD for ultimate sensitivity,” Opt. Lett. 25, 1648–1650 (2000).
[CrossRef]

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Poenie, M.

R. Y. Tsien, M. Poenie, “Fluorescence ratio imaging: a new window into intracellular ionic signalling,” Trends Biochem. Sci. 11, 450–455 (1986).
[CrossRef]

Prendergast, F. G.

J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
[CrossRef] [PubMed]

Provencher, S. W.

S. W. Provencher, “contin: a general purpose constrained regularization program for inverting noisy linear algebraic and integral equations,” Comput. Phys. Commun. 27, 229–242 (1982).
[CrossRef]

Qu, J. Y.

J. Y. Qu, J. W. Hua, Z. J. Huang, “Correction of geometrical effects on fluorescence imaging of tissue,” Opt. Commun. 176, 319–326 (2000).
[CrossRef]

J. Y. Qu, “Real time calibrated fluorescence imaging of tissue in vivo by using the combination of fluorescence and cross-polarized reflection,” in Biomedical Topical Meetings, Vol. 71 of OSA Trends in Optics and Photonics Series (Optical Society of America, Washington, D.C., 2002), pp. 485–487.

Reed, M.

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

Rinaldi, F.

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Rossi-Bernardi, L.

Rouse, A. R.

Sabharwal, Y. S.

Salani, G.

Schneider, P. C.

See, for instance, P. C. Schneider, R. M. Clegg, “Rapid acquisition analysis and display of fluorescence lifetime-resolved images for real-time applications,” Rev. Sci. Instrum. 68, 4107–4119 (1997).
[CrossRef]

Shibuya, H.

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

Sibbett, W.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

Siegel, J.

D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
[CrossRef]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Sinaasappel, M.

Sorbellini, E.

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Squire, A.

P. I. H. Bastiaens, A. Squire, “Fluorescence lifetime imaging microscopy: spatial resolution of biochemical processes in the cell,” Trends Cell Biol. 9, 48–52 (1999).
[CrossRef] [PubMed]

Star, W. M.

G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).

Stepinac, T.

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

Sterenborg, H. J. C. M.

Tait, I.

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

Taroni, P.

See, for instance,G. Valentini, C. D’Andrea, D. Comelli, A. Pifferi, P. Taroni, A. Torricelli, R. Cubbeddu, C. Battaglia, C. Consolandi, G. Salani, L. Rossi-Bernardi, G. De Bellis, “Time-resolved DNA-microarray reading by an intensified CCD for ultimate sensitivity,” Opt. Lett. 25, 1648–1650 (2000).
[CrossRef]

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Tearney, G. J.

Torricelli, A.

See, for instance,G. Valentini, C. D’Andrea, D. Comelli, A. Pifferi, P. Taroni, A. Torricelli, R. Cubbeddu, C. Battaglia, C. Consolandi, G. Salani, L. Rossi-Bernardi, G. De Bellis, “Time-resolved DNA-microarray reading by an intensified CCD for ultimate sensitivity,” Opt. Lett. 25, 1648–1650 (2000).
[CrossRef]

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

Tsien, R. Y.

R. Y. Tsien, M. Poenie, “Fluorescence ratio imaging: a new window into intracellular ionic signalling,” Trends Biochem. Sci. 11, 450–455 (1986).
[CrossRef]

Valentini, G.

See, for instance,G. Valentini, C. D’Andrea, D. Comelli, A. Pifferi, P. Taroni, A. Torricelli, R. Cubbeddu, C. Battaglia, C. Consolandi, G. Salani, L. Rossi-Bernardi, G. De Bellis, “Time-resolved DNA-microarray reading by an intensified CCD for ultimate sensitivity,” Opt. Lett. 25, 1648–1650 (2000).
[CrossRef]

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

van den Bergh, H.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

Wagnieres, G.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

Wagnieres, G. A.

G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).

Wahl, M.

Ware, W. R.

D. R. James, W. R. Ware, “A fallacy in the interpretation of fluorescence decay parameters,” Chem. Phys. Lett. 120, 455–459 (1985).
[CrossRef]

Webb, R. H.

Webb, S. E. D.

D. S. Elson, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Lever, P. M. W. French, K. Lauritsen, M. Wahl, R. Erdmann, “Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser,” Opt. Lett. 27, 1409–1411 (2002).
[CrossRef]

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

Weiss, A.

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

Weiss, G.

W. Becker, A. Bergmann, G. Weiss, “Lifetime imaging with the Zeiss LSM-510,” in Multiphoton Microscopy in the Biomedical Sciences II, A. Periasamy, W. M. Keck, P. T. C. So, eds., Proc. SPIE4620, 30–35 (2002).
[CrossRef]

Wilson, B. C.

G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).

Zellweger, M.

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Zeng, H.

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

Appl. Opt. (2)

Bioimaging (1)

H. Zeng, A. Weiss, R. Cline, C. E. MacAuley, “Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract,” Bioimaging 6, 151–165 (1998).
[CrossRef]

Biophys. J. (2)

K. C. Benny Lee, J. Siegel, S. E. D. Webb, S. Lévêque-Fort, M. J. Cole, R. Jones, K. Dowling, M. J. Lever, P. M. W. French, “Application of the stretched exponential function to fluorescence lifetime imaging,” Biophys. J. 81, 1265–1274 (2001).
[CrossRef]

J. R. Alcala, E. Gratton, F. G. Prendergast, “Fluorescence lifetime distributions in proteins,” Biophys. J. 51, 597–604 (1987).
[CrossRef] [PubMed]

Br. J. Cancer (1)

N. Lange, P. Jichlinski, M. Zellweger, M. Forrer, A. Marti, L. Guillou, P. Kucera, G. Wagnieres, H. van den Bergh, “Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study,” Br. J. Cancer 80, 185–193 (1999).
[CrossRef] [PubMed]

Cancer (1)

H. Ina, H. Shibuya, I. Ohashi, M. Kitagawa, “The frequency of a concomitant early esophageal cancer in male patients with oral and oropharyngeal cancer. Screening results using Lugol dye endoscopy,” Cancer 73, 2038–2041 (1994).
[CrossRef] [PubMed]

Chem. Phys. Lett. (1)

D. R. James, W. R. Ware, “A fallacy in the interpretation of fluorescence decay parameters,” Chem. Phys. Lett. 120, 455–459 (1985).
[CrossRef]

Comput. Phys. Commun. (1)

S. W. Provencher, “contin: a general purpose constrained regularization program for inverting noisy linear algebraic and integral equations,” Comput. Phys. Commun. 27, 229–242 (1982).
[CrossRef]

IEEE J. Sel. Top. Quantum Electron. (1)

R. Cubeddu, A. Pifferi, P. Taroni, A. Torricelli, G. Valentini, F. Rinaldi, E. Sorbellini, “Fluorescence lifetime imaging: an application to the detection of skin tumors,” IEEE J. Sel. Top. Quantum Electron. 5, 923–929 (1999).
[CrossRef]

J. Chem. Phys. (1)

J. R. Alcala, “The effect of harmonic conformational trajectories on protein fluorescence and lifetime distributions,” J. Chem. Phys. 101, 4578–4584 (1994).
[CrossRef]

J. Mod. Opt. (1)

K. Dowling, M. J. Dayel, S. C. W. Hyde, P. M. W. French, M. J. Lever, J. D. Hares, A. K. L. Dymoke-Bradshaw, “High resolution time-domain fluorescence lifetime imaging for biomedical applications,” J. Mod. Opt. 46(2), 199–209 (1999).

Las. Med. Sci. (1)

J. Mizeret, G. Wagnieres, T. Stepinac, H. Van Den Bergh, “Endoscopic tissue characterization by frequency-domain fluorescence lifetime imaging (FD-FLIM),” Las. Med. Sci. 12, 209–217 (1997).
[CrossRef]

Opt. Commun. (1)

J. Y. Qu, J. W. Hua, Z. J. Huang, “Correction of geometrical effects on fluorescence imaging of tissue,” Opt. Commun. 176, 319–326 (2000).
[CrossRef]

Opt. Lett. (4)

Photochem. Photobiol. (2)

R. Ackroyd, C. Kelty, N. Brown, M. Reed, “The history of photodetection and photodynamic therapy,” Photochem. Photobiol. 74, 656–669 (2001).
[CrossRef] [PubMed]

G. A. Wagnieres, W. M. Star, B. C. Wilson, “In vivo fluorescence spectroscopy and imaging for oncological applications,” Photochem. Photobiol. 68, 603–632 (1998).

Phys. Rev. B (1)

F. Alvarez, A. Alegría, J. Colmenero, “Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions,” Phys. Rev. B 44, 7306–7312 (1991).
[CrossRef]

Rev. Sci. Instrum. (2)

See, for instance, P. C. Schneider, R. M. Clegg, “Rapid acquisition analysis and display of fluorescence lifetime-resolved images for real-time applications,” Rev. Sci. Instrum. 68, 4107–4119 (1997).
[CrossRef]

T. McKechnie, A. Jahan, I. Tait, A. Cuschieri, W. Sibbett, M. Padgett, “An endoscopic system for the early detection of cancers of the gastrointestinal tract,” Rev. Sci. Instrum. 69, 2521–2523 (1998).
[CrossRef]

Trends Biochem. Sci. (1)

R. Y. Tsien, M. Poenie, “Fluorescence ratio imaging: a new window into intracellular ionic signalling,” Trends Biochem. Sci. 11, 450–455 (1986).
[CrossRef]

Trends Cell Biol. (1)

P. I. H. Bastiaens, A. Squire, “Fluorescence lifetime imaging microscopy: spatial resolution of biochemical processes in the cell,” Trends Cell Biol. 9, 48–52 (1999).
[CrossRef] [PubMed]

Other (4)

W. Becker, A. Bergmann, G. Weiss, “Lifetime imaging with the Zeiss LSM-510,” in Multiphoton Microscopy in the Biomedical Sciences II, A. Periasamy, W. M. Keck, P. T. C. So, eds., Proc. SPIE4620, 30–35 (2002).
[CrossRef]

J. R. Lakowicz, Principles of Fluorescence Spectroscopy (Kluwer, New York, 1999).
[CrossRef]

J. Y. Qu, “Real time calibrated fluorescence imaging of tissue in vivo by using the combination of fluorescence and cross-polarized reflection,” in Biomedical Topical Meetings, Vol. 71 of OSA Trends in Optics and Photonics Series (Optical Society of America, Washington, D.C., 2002), pp. 485–487.

Spatial image quality is a measure of lifetime variability between connected pixels within regions of the same average lifetime; image contrast measures lifetime variation between averaged regions.

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Figures (8)

Fig. 1
Fig. 1

Experimental setup for a compact FLIM microscopy system. The picosecond diode laser is fiber coupled, and its electronic trigger output is used to synchronize the gated optical intensifier (GOI) through an adjustable delay.

Fig. 2
Fig. 2

(a) Light microscopy image of a 15-μm-thick unstained section of rat tissue. The two marked regions indicate the locations where FLIM microscopy was performed [region A, Figs. 2(b)2(d); region B, Fig. 3] (b) Time-gated autofluorescence microscopy image of region A at ×20 magnification of the section, upon irradiation with a pulsed diode laser (35 ps, 405 nm, 40 MHz). (c) FLIM map obtained from a series of 21 images including (b), recorded at different delays with respect to the excitation pulse. A single-exponential decay was fitted, and the resulting fluorescence lifetime τ0 is represented in a false colour scale with the range indicated. Purple/blue colours represent fast fluorescence decays; yellow/red colors, slow decays. (d) Merged lifetime map formed by combining the lifetime (c) and intensity (b) images. This allows the functional lifetime information to be related to the anatomical intensity image without losing information from either parameter.

Fig. 3
Fig. 3

Comparison of the performance of different decay models applied to FLIM microscopy data acquired from region B of the unstained tissue section at ×100 magnification. (a) Time-gated fluorescence image (b) FLIM map obtained from a single exponential fit, displaying the lifetime τ0. [The arrow indicates the pixel used in (Fig. 4) to analyze the decay] (c) FLIM map obtained from a stretched exponential fit, displaying the mean lifetime 〈τ〉. (d) Heterogeneity map obtained from a stretched exponential fit, displaying the heterogeneity parameter h. (e)–(g) FLIM maps obtained from a double exponential fit, displaying (e) the fast decay constant τ1, (f) the slow decay constant τ2, and (g) the (physically meaningless) weighted average lifetime τav.

Fig. 4
Fig. 4

Shows the sampled fluorescence intensity decay (circles) of a single pixel of the artery wall [arrow in Fig. 3(b)] comparing the performance of the fitting models (curves). The lower part of this graph shows the residuals of the fits.

Fig. 5
Fig. 5

(a) Fluorescence lifetime distribution as extracted by the contin algorithm from experimental fluorescence decay data of a single pixel [marked by an arrow in Fig. 3(b)]. (b) Fluorescence decay data (circles) from this single pixel with fitted curves provided by the contin algorithm and by the StrEF. The residuals of the fits, given in the lower part of the figure, show a comparable goodness of fit.

Fig. 6
Fig. 6

Experimental setup for FLIM endoscopy.

Fig. 7
Fig. 7

(a) Temporal broadening of 100-fs pulses to 46 ps in the multimode imaging bundle of the endoscope, as measured with a Streak Camera (resolution, ∼35 ps). (b) FLIM endoscopy images of a multiwell plate sample containing the dye DASPI in solvents of different viscosity (ethanol/glycerol ratios from bottom to top: 20/80, 40/60, 60/40, 80/20, 100/0). As the viscosity increases from top to bottom, the lifetime increases. The false color scale spans from 0 ps (purple) to 700 ps (red).

Fig. 8
Fig. 8

Endoscopy images of a rabbit joint (a)–(c) and a longitudinal section of a human tooth (d)–(f): (a) and (d) dc white-light reflection images, (b) and (e) time-gated fluorescence intensity images (c) and (f) FLIM maps, contrasting the different regions according to their characteristic fluorescence lifetime. Rabbit joint (c): The region where the tendon attaches to the bone exhibits long lifetimes (red/yellow). Human tooth (f): The outer enamel layer has a much shorter lifetime (violet) than the dentine (green) or the root canal region (yellow/red).

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

It=I0 exp-tτ0+const.
It=in Ii exp-tτi+const., n=1, 2, 3,.
It=I0 exp-tτkww1/h+const.,
It=0exp-tτρτdτ.
τ=hτkwwΓh,

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