Advances in quantitative UV-visible spectroscopy for clinical and pre-clinical application in cancer

Current Opinion in Biotechnology

Volumn 20, Issue 1, 2009, Pages 119-131

  Brown, J Quincy ^a   Vishwanath, Karthik ^a   Palmer, Gregory M ^b   Ramanujam, Nirmala ^a  

^a USA   (United States)

^b DUKE UNIVERSITY MEDICAL CENTER   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CELLULAR PROLIFERATIONS; CLINICAL APPLICATIONS; EXTRA CELLULAR MATRICES; FLUORESCENCE SPECTRUM; IMMUNOHISTOCHEMISTRY; MEASURED PARAMETERS; OPTICAL SPECTROSCOPIES; REDOX STATE; TISSUE PROPERTIES; TISSUE SPECTROSCOPIES; UV-VISIBLE; UV-VISIBLE SPECTROSCOPIES;

CELL PROLIFERATION; OXYGENATION; ULTRAVIOLET SPECTROSCOPY;

DIAGNOSIS;

ALGORITHM; ANGIOGENESIS; BLOOD VOLUME; CALIBRATION; CANCER DIAGNOSIS; HYPOXIA; IMMUNOHISTOCHEMISTRY; OXIDATION; OXYGENATION; PRIORITY JOURNAL; REVIEW; SPECTRAL SENSITIVITY; ULTRAVIOLET SPECTROSCOPY;

ANIMALS; BREAST NEOPLASMS; FEMALE; HUMANS; SPECTROMETRY, FLUORESCENCE; SPECTROPHOTOMETRY, ULTRAVIOLET; SPECTROSCOPY, NEAR-INFRARED; UTERINE CERVICAL NEOPLASMS;

EID: 65449127117     PISSN: 09581669     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.copbio.2009.02.004     Document Type: Review

References (100)

1. Duffy M.J., and Crown J. A personalized approach to cancer treatment: how biomarkers can help. Clin Chem 54 (2008) 1770-1779
2. Hockel M., and Vaupel P. Tumor hypoxia: definitions and current clinical, biologic, and molecular aspects. J Natl Cancer Inst 93 (2001) 266-276
3. Vaupel P., and Mayer A. Hypoxia in cancer: significance and impact on clinical outcome. Cancer Metastasis Rev 26 (2007) 225-239
4. Evans S.M., and Koch C.J. Prognostic significance of tumor oxygenation in humans. Cancer Lett 195 (2003) 1-16
5. Tatum J.L., Kelloff G.J., Gillies R.J., Arbeit J.M., Brown J.M., Chao K.S., Chapman J.D., Eckelman W.C., Fyles A.W., Giaccia A.J., et al. Hypoxia: importance in tumor biology, noninvasive measurement by imaging, and value of its measurement in the management of cancer therapy. Int J Radiat Biol 82 (2006) 699-757
6. Dewhirst M.W., Richardson R., Cardenas-Navia I., and Cao Y. The relationship between the tumor physiologic microenvironment and angiogenesis. Hematol Oncol Clin North Am 18 (2004) 973-990 vii
7. Hanahan D., and Weinberg R.A. The hallmarks of cancer. Cell 100 (2000) 57-70
8. Rajendran J.G., and Krohn K.A. Imaging hypoxia and angiogenesis in tumors. Radiol Clin North Am 43 (2005) 169-187
9. Cook J.A., Gius D., Wink D.A., Krishna M.C., Russo A., and Mitchell J.B. Oxidative stress, redox, and the tumor microenvironment. Semin Radiat Oncol 14 (2004) 259-266
10. Poptani H., Bansal N., Jenkins W.T., Blessington D., Mancuso A., Nelson D.S., Feldman M., Delikatny E.J., Chance B., and Glickson J.D. Cyclophosphamide treatment modifies tumor oxygenation and glycolytic rates of RIF-1 tumors: 13C magnetic resonance spectroscopy, Eppendorf electrode, and redox scanning. Cancer Res 63 (2003) 8813-8820
11. Hyodo F., Matsumoto K., Matsumoto A., Mitchell J.B., and Krishna M.C. Probing the intracellular redox status of tumors with magnetic resonance imaging and redox-sensitive contrast agents. Cancer Res 66 (2006) 9921-9928
12. Matsumoto K., Hyodo F., Matsumoto A., Koretsky A.P., Sowers A.L., Mitchell J.B., and Krishna M.C. High-resolution mapping of tumor redox status by magnetic resonance imaging using nitroxides as redox-sensitive contrast agents. Clin Cancer Res 12 (2006) 2455-2462
13. He S., Dunn K.L., Espino P.S., Drobic B., Li L., Yu J., Sun J.M., Chen H.Y., Pritchard S., and Davie J.R. Chromatin organization and nuclear microenvironments in cancer cells. J Cell Biochem 104 (2008) 2004-2015
14. Brooksby B., Pogue B., Jiang S., Dehghani H., Srinivasan S., Kogel C., Tosteson T., Weaver J., Poplack S., and Paulsen K. Imaging breast adipose and fibroglandular tissue molecular signatures by using hybrid MRI-guided near-infrared spectral tomography. PNAS 103 (2006) 8828-8833
15. Cerussi A.E., Shah N., Hsiang D., Durkin A., Butler J., and Tromberg B. In vivo absorption, scattering, and physiologic properties of 58 malignant breast tumors determined by broadband diffuse optical spectroscopy. J Biomed Opt 11 (2006) 044005
16. Liotta L.A., and Kohn E.C. The microenvironment of the tumour-host interface. Nature 411 (2001) 375-379
17. Torigian D.A., Huang S.S., Houseni M., and Alavi A. Functional imaging of cancer with emphasis on molecular techniques. CA Cancer J Clin 57 (2007) 206-224
18. Neves A.A., and Brindle K.M. Assessing responses to cancer therapy using molecular imaging. Biochim Biophys Acta 1766 (2006) 242-261
19. Sokolov K., Follen M., and Richards-Kortum R. Optical spectroscopy for detection of neoplasia. Curr Opin Chem Biol 6 (2002) 651-658
20. Bigio I.J., and Bown S.G. Spectroscopic sensing of cancer and cancer therapy: current status of translational research. Cancer Biol Ther 3 (2004) 259-267
21. Chang S., Mirabal Y., Atkinson E., Cox D., Malpica A., Follen M., and Richards-Kortum R. Combined reflectance and fluorescence spectroscopy for in vivo detection of cervical pre-cancer. J Biomed Opt 10 (2005) 024031
22. Xu R.X., and Povoski S.P. Diffuse optical imaging and spectroscopy for cancer. Expert Rev Med Devices 4 (2007) 83-95
23. Badizadegan K., Backman V., Boone C., Crum C., Dasari R., Georgakoudi I., Keefe K., Munger K., Shapshay S., Sheetse E., et al. Spectroscopic diagnosis and imaging of invisible pre-cancer. Faraday Discuss 126 (2004) 265-279
24. Cerussi A., Hsiang D., Shah N., Mehta R., Durkin A., Butler J., and Tromberg B.J. Predicting response to breast cancer neoadjuvant chemotherapy using diffuse optical spectroscopy. Proc Natl Acad Sci U S A 104 (2007) 4014-4019. This NIR study showed the potential of optical spectroscopy as an early indicator of response to chemotherapy in 11 patients, and is an example of the therapeutic utility of optical spectroscopy in breast cancer.
25. Jakubowski D.B., Cerussi A.E., Bevilacqua F., Shah N., Hsiang D., Butler J., and Tromberg B.J. Monitoring neoadjuvant chemotherapy in breast cancer using quantitative diffuse optical spectroscopy: a case study. J Biomed Opt 9 (2004) 230-238
26. Choe R., Corlu A., Lee K., Durduran T., Konecky S.D., Grosicka-Koptyra M., Arridge S.R., Czerniecki B.J., Fraker D.L., DeMichele A., et al. Diffuse optical tomography of breast cancer during neoadjuvant chemotherapy: a case study with comparison to MRI. Med Phys 32 (2005) 1128-1139
27. Sunar U., Quon H., Durduran T., Zhang J., Du J., Zhou C., Yu G., Choe R., Kilger A., Lustig R., et al. Noninvasive diffuse optical measurement of blood flow and blood oxygenation for monitoring radiation therapy in patients with head and neck tumors: a pilot study. J Biomed Opt 11 (2006) 064021
28. Welch A.J., and Gemert M.J.C.V. Optical-thermal Response of Laser-irradiated Tissue (1995), Plenum Press, New York
29. In: Vo-Dinh T. (Ed). Biomedical Photonics Handbook (2003), CRC Press, New York
30. Arridge S. Optical tomography in medical imaging. Inverse Problems 15 (1999) R41-R93
31. Hielscher A.H., Bluestone A.Y., Abdoulaev G.S., Klose A.D., Lasker J., Stewart M., Netz U., and Beuthan J. Near-infrared diffuse optical tomography. Dis Markers 18 (2002) 313-337
32. Richards-Kortum R., and Sevick-Muraca E. Quantitative optical spectroscopy for tissue diagnosis. Annu Rev Phys Chem 47 (1996) 555-606
33. Tuchin V.V. Handbook of Optical Biomedical Diagnostics (2002), SPIE Press, Bellingham, Washington
34. In: Mycek M.-A., and Pogue B.W. (Eds). Handbook of Biomedical Fluorescence (2003), Marcel Dekker, Inc., New York
35. Bigio I., and Mourant J. Ultraviolet and visible spectroscopies for tissue diagnostics: fluorescence spectroscopy and elastic-scattering spectroscopy. Phys Med Biol 42 (1997) 803-814
36. Zuzak K.J., Schaeberle M.D., Gladwin M.T., Cannon III R.O., and Levin I.W. Noninvasive determination of spatially resolved and time-resolved tissue perfusion in humans during nitric oxide inhibition and inhalation by use of a visible-reflectance hyperspectral imaging technique. Circulation 104 (2001) 2905-2910
37. Srinivasan S., Pogue B.W., Jiang S., Dehghani H., Kogel C., Soho S., Gibson J.J., Tosteson T.D., Poplack S.P., and Paulsen K.D. Interpreting hemoglobin and water concentration, oxygen saturation, and scattering measured in vivo by near-infrared breast tomography. PNAS 100 (2003) 12349-12354
38. Bigio I.J., Bown S.G., Briggs G., Kelley C., Lakhani S., Pickard D., Ripley P.M., Rose I.G., and Saunders C. Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results. J Biomed Opt 5 (2000) 221-228
39. Bohren C.F., and Huffman D.A. Absorption and Scattering of Light by Small Particles (1983), John Wiley & Sons, New York
40. Georgakoudi I., and Feld M.S. The combined use of fluorescence, reflectance, and light-scattering spectroscopy for evaluating dysplasia in Barrett's esophagus. Gastrointest Endosc Clin N Am 14 (2004) 519-537
41. Andersson-Engels S., Klinteberg C., Svanberg K., and Svanberg S. In vivo fluorescence imaging for tissue diagnostics. Phys Med Biol 42 (1997) 815-824
42. Ramanujam N. Fluorescence spectroscopy of neoplastic and non-neoplastic tissues. Neoplasia 2 (2000) 89-117
43. Georgakoudi I., Jacobson B.C., Van Dam J., Backman V., Wallace M.B., Muller M.G., Zhang Q., Badizadegan K., Sun D., Thomas G.A., et al. Fluorescence, reflectance, and light-scattering spectroscopy for evaluating dysplasia in patients with Barrett's esophagus. Gastroenterology 120 (2001) 1620-1629
44. Skala M.C., Riching K.M., Gendron-Fitzpatrick A., Eickhoff J., Eliceiri K.W., White J.G., and Ramanujam N. In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia. Proc Natl Acad Sci U S A 104 (2007) 19494-19499
45. Taroni P., Pifferi A., Torricelli A., Comelli D., and Cubeddu R. In vivo absorption and scattering spectroscopy of biological tissues. Photochem Photobiol Sci 2 (2003) 124-129
46. Zhu C., Liu Q., and Ramanujam N. Effect of fiber optic probe geometry on depth-resolved fluorescence measurements from epithelial tissues: a Monte Carlo simulation. J Biomed Opt 8 (2003) 237-247
47. Liu Q., and Ramanujam N. Experimental proof of the feasibility of using an angled fiber-optic probe for depth-sensitive fluorescence spectroscopy of turbid media. Optics Lett 29 (2004) 2034-2036
48. Pfefer T.J., Agrawal A., and Drezek R.A. Oblique-incidence illumination and collection for depth-selective fluorescence spectroscopy. J Biomed Opt 10 (2005) 044016
49. Liu Q., and Ramanujam N. Sequential estimation of optical properties of a two-layered epithelial tissue model from depth-resolved ultraviolet-visible diffuse reflectance spectra. Appl Opt 45 (2006) 4776-4790
50. Amelink A., Sterenborg H.J.C.M., Bard M.P.L., and Burgers S.A. In vivo measurement of the local optical properties of tissue by use of differential path-length spectroscopy. Opt Lett 29 (2004) 1087-1089
51. Ohno Y. Improved photometric standards and calibration procedures at NIST. J Res Natl Inst Standards Technol 102 (1997) 323-331
52. DeCusatis C., and Optical Society of America. Handbook of Applied Photometry (1997), AIP Press; Optical Society of America, Woodbury, N.Y. Washington, DC
53. Pogue B.W., and Patterson M.S. Review of tissue simulating phantoms for optical spectroscopy, imaging and dosimetry. J Biomed Opt 11 (2006) 041102
54. Resch-Genger U., Hoffmann K., Nietfeld W., Engel A., Neukammer J., Nitschke R., Ebert B., and Macdonald R. How to improve quality assurance in fluorometry: fluorescence-inherent sources of error and suited fluorescence standards. J Fluorescence 15 (2005) 337-362
55. Baeten J., Niedre M., Dunham J., and Ntziachristos V. Development of fluorescent materials for Diffuse Fluorescence Tomography standards and phantoms. Opt Express 15 (2007) 8681-8694
56. Les C.B. Spectroscopy focus: NIST develops calibration tools for fluorescent instruments. Photonics Spectra 41 (2007) 99-100
57. Gaigalas A.K., Li L., Henderson O., Vogt R., Barr J., Marti G., Weaver J., and Schwartz A. The development of fluorescence intensity standards. J Res Natl Inst Standards Technol 106 (2001) 381-389
58. DeRose P.C., Early E.A., and Kramer G.W. Qualification of a fluorescence spectrometer for measuring true fluorescence spectra. Rev Scientific Instrum 78 (2007) 033107
59. Marin N.M., MacKinnon N., MacAulay C., Chang S.K., Atkinson E.N., Cox D., Serachitopol D., Pikkula B., Follen M., and Richards-Kortum R. Calibration standards for multicenter clinical trials of fluorescence spectroscopy for in vivo diagnosis. Journal of Biomedical Optics 11 (2006) 14010-14011
60. Palmer G.M., and Ramanujam N. Monte-Carlo-based model for the extraction of intrinsic fluorescence from turbid media. J Biomed Opt 13 (2008) 024017. Describes the application of an inverse Monte Carlo model for extraction of tissue optical properties allowing recovery of intrinsic fluorescence spectra unfettered by tissue absorption and scattering.
61. Kienle A., and Patterson M.S. Determination of the optical properties of turbid media from a single Monte Carlo simulation. Phys Med Biol 41 (1996) 2221-2227
62. Thueler P., Charvet I., Bevilacqua F., Ghislain M.S., Ory G., Marquet P., Meda P., Vermeulen B., and Depeursinge C. In vivo endoscopic tissue diagnostics based on spectroscopic absorption, scattering, and phase function properties. J Biomed Opt 8 (2003) 495-503
63. Palmer G.M., and Ramanujam N. Monte Carlo-based inverse model for calculating tissue optical properties. Part I: theory and validation on synthetic phantoms. Appl Opt 45 (2006) 1062-1071
64. Aerts J.G.J.V., Amelink A., van der Leest C., Hegmans J.P.J.J., Hemmes A., den Hamer B., Sterenborg H.C.J.M., Hoogsteden H.C., and Lambrecht B.N. HIF1a expression in bronchial biopsies correlates with tumor microvascular saturation determined using optical spectroscopy. Lung Cancer 57 (2007) 317-321. An example of clinical validation of quantitative spectroscopy, this study correlated in vivo hemoglobin saturation measurements in the lung with independent molecular markers for hypoxia.
65. Amelink A., Kaspers O.P., Sterenborg H.J.C.M., van der Wal J.E., Roodenburg J.L.N., and Witjes M.J.H. Non-invasive measurement of the morphology and physiology of oral mucosa by use of optical spectroscopy. Oral Oncol 44 (2008) 65-71
66. Bard M.P., Amelink A., Hegt V.N., Graveland W.J., Sterenborg H.J., Hoogsteden H.C., and Aerts J.G. Measurement of hypoxia-related parameters in bronchial mucosa by use of optical spectroscopy. Am J Respir Crit Care Med 171 (2005) 1178-1184
67. Chang S.K., Marin N., Follen M., and Richards-Kortum R. Model-based analysis of clinical fluorescence spectroscopy for in vivo detection of cervical intraepithelial dysplasia. J Biomed Opt (2006) 11. Describes the application of a two-layered tissue model for quantitative analysis of fluorescence remitted from the uterine cervix in vivo.
68. Fawzy Y.S., Petek M., Tercelj M., and Zeng H.S. In vivo assessment and evaluation of lung tissue morphologic and physiological changes from non-contact endoscopic reflectance spectroscopy for improving lung cancer detection. J Biomed Opt (2006) 11
69. Mourant J.R., Bocklage T.J., Powers T.M., Greene H.M., Bullock K.L., Marr-Lyon L.R., Dorin M.H., Waxman A.G., Zsemlye M.M., and Smith H.O. In vivo light scattering measurements for detection of precancerous conditions of the cervix. Gynecol Oncol 105 (2007) 439-445
70. Palmer G.M., Zhu C., Breslin T.M., Xu F., Gilchrist K.W., and Ramanujam N. Monte Carlo-based inverse model for calculating tissue optical properties. Part II: application to breast cancer diagnosis. Appl Opt 45 (2006) 1072-1078
71. Sun J., Fu K., Wang A., Lin A.W.H., Utzinger U., and Drezek R. Influence of fiber optic probe geometry on the applicability of inverse models of tissue reflectance spectroscopy: computational models and experimental measurements. Appl Opt 45 (2006) 8152-8162
72. van Veen R.L.P., Amelink A., Menke-Pluymers M., van der Pol C., and Sterenborg H.J.C.M. Optical biopsy of breast tissue using differential path-length spectroscopy. Phys Med Biol 50 (2005) 2573-2581
73. Volynskaya Z., Haka A.S., Bechtel K.L., Fitzmaurice M., Shenk R., Wang N., Nazemi J., Dasari R.R., and Feld M.S. Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy. J Biomed Opt 13 (2008) 024012
74. Zhu C.F., Palmer G.M., Breslin T.M., Harter J., and Ramanujam N. Diagnosis of breast cancer using diffuse reflectance spectroscopy: comparison of a Monte Carlo versus partial least squares analysis based feature extraction technique. Lasers Surg Med 38 (2006) 714-724
75. Zhu C.F., Palmer G.M., Breslin T.M., Harter J., and Ramanujam N. Diagnosis of breast cancer using fluorescence and diffuse reflectance spectroscopy: a Monte-Carlo-model-based approach. J Biomed Opt 13 (2008) 034015
76. Zonios G., and Dimou A. Modeling diffuse reflectance from semi-infinite turbid media: application to the study of skin optical properties. Opt Express 14 (2006) 8661-8674
77. Zonios G., Dimou A., and Galaris D. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy. Phys Med Biol 53 (2008) 269-278
78. Vishwanath K., Yuan H., Moore L., Bender J., Dewhirst M., and Ramanujam N. Longitudinal monitoring of 4T1-tumor physiology in vivo with Doxorubicin treatment via diffuse optical spectroscopy. Abstract number BTuC3, OSA Topical Meeting, Biomedical Optics, Washington DC (2008)
79. Vaupel P., Hockel M., and Mayer A. Detection and characterization of tumor hypoxia using pO2 histography. Antioxid Redox Signal 9 (2007) 1221-1235
80. Lundgren K., Holm C., and Landberg G. Hypoxia and breast cancer: prognostic and therapeutic implications. Cell Mol Life Sci 64 (2007) 3233-3247
81. Brennan D.J., Jirstrom K., Kronblad A., Millikan R.C., Landberg G., Duffy M.J., Ryden L., Gallagher W.M., and O'Brien S.L. CA IX is an independent prognostic marker in premenopausal breast cancer patients with one to three positive lymph nodes and a putative marker of radiation resistance. Clin Cancer Res 12 (2006) 6421-6431
82. Ghosh N., Mohanty S.K., Majumder S.K., and Gupta P.K. Measurement of optical transport properties of normal and malignant human breast tissue. Appl Opt 40 (2001) 176-184
83. Brown JQ, Wilke LG, Geradts J, Kennedy SA, Palmer GM, Ramanujam N: Quantitative optical spectroscopy: A robust tool for direct measurement of breast cancer vascular oxygenation and total hemoglobin content in vivo. Cancer Res 2009, in press (April 1).
84. Dellas A., Moch H., Schultheiss E., Feichter G., Almendral A.C., Gudat F., and Torhorst J. Angiogenesis in cervical neoplasia: microvessel quantitation in precancerous lesions and invasive carcinomas with clinicopathological correlations. Gynecol Oncol 67 (1997) 27-33
85. Abulafia O., and Sherer D.M. Angiogenesis in the uterine cervix. Int J Gynecol Cancer 10 (2000) 349-357
86. Pavlova I., Sokolov K., Drezek R., Malpica A., Follen M., and Richards-Kortum R. Microanatomical and biochemical origins of normal and precancerous cervical autofluorescence using laser-scanning fluorescence confocal microscopy. Photochem Photobiol 77 (2003) 550-555
87. Collier T., Arifler D., Malpica A., Follen M., and Richards-Kortum R. Determination of epithelial tissue scattering coefficient using confocal microscopy. IEEE J Sel Top Quantum Electron 9 (2003) 307-313
88. Georgakoudi I., Jacobson B.C., Muller M.G., Sheets E.E., Badizadegan K., Carr-Locke D.L., Crum C.P., Boone C.W., Dasari R.R., Van Dam J., et al. NAD(P)H and collagen as in vivo quantitative fluorescent biomarkers of epithelial precancerous changes. Cancer Res 62 (2002) 682-687
89. Georgakoudi I., Sheets E.E., Muller M.G., Backman V., Crum C.P., Badizadegan K., Dasari R.R., and Feld M.S. Trimodal spectroscopy for the detection and characterization of cervical precancers in vivo. Am J Obstet Gynecol 186 (2002) 374-382
90. Ramanujam N., Mitchell M.F., Mahadevan A., Warren S., Thomsen S., Silva E., and Richards-Kortum R. In vivo diagnosis of cervical intraepithelial neoplasia using 337-nm-excited laser-induced fluorescence. Proc Natl Acad Sci U S A 91 (1994) 10193-10197
91. Mayevsky A., and Chance B. Intracellular oxidation-reduction state measured in situ by a multichannel fiber-optic surface fluorometer. Science 217 (1982) 537-540
92. Chang VT, Cartwright PS, Bean SM, Palmer GM, Bentley RC, Ramanujam N: Quantitative physiology of the precancerous cervix in vivo through optical spectroscopy. Neoplasia 2009, in press.
93. Chang S.K., Arifler D., Drezek R., Follen M., and Richards-Kortum R. Analytical model to describe fluorescence spectra of normal and preneoplastic epithelial tissue: comparison with Monte Carlo simulations and clinical measurements. J Biomed Opt 9 (2004) 511-522
94. Amelink A., Robinson D.J., and Sterenborg H.J.C.M. Confidence intervals on fit parameters derived from optical reflectance spectroscopy measurements. J Biomed Opt 13 (2008) 054044
95. Arridge S.R., and Lionheart W.R. Nonuniqueness in diffusion-based optical tomography. Opt Lett 23 (1998) 882-884
96. Finlay J.C., and Foster T.H. Effect of pigment packaging on diffuse reflectance spectroscopy ofsamples containing red blood cells. Opt Lett 29 (2004) 965-967
97. Nath A., Rivoire K., Chang S., Cox D., Atkinson E.N., Follen M., and Richards-Kortum R. Effect of probe pressure on cervical fluorescence spectroscopy measurements. J Biomed Opt 9 (2004) 523-533
98. Reif R., Amorosino M.S., Calabro K.W., A'Amar O., Singh S.K., and Bigio I.J. Analysis of changes in reflectance measurements on biological tissues subjected to different probe pressures. J Biomed Opt 13 (2008) 010502
99. Ti Y., and Lin W.-C. Effects of probe contact pressure on in vivo optical spectroscopy. Opt Express 16 (2008) 4250-4262
100. Yu B., Fu H., Bydlon T., Bender J.E., and Ramanujam N. Diffuse reflectance spectroscopy with a self-calibrating fiber optic probe. Opt Lett 33 (2008) 1783-1785