Physics of Photodynamic Therapy



Photodynamic therapy (PDT) uses light-activated drugs (photosensitizers) for the treatment of neoplastic and non-neoplastic diseases. Administration of the photosensitizer constitutes the first step in the PDT process. Then, following a waiting period (minutes to days) to allow for selective accumulation in the target tissue, the sensitizer is activated via light (usually from a laser) of a wavelength matching a prominent absorption resonance in the red or near-infrared part of the visible spectrum. Absorption of this light by the photosensitizer results in photochemical processes which ultimately produce the cytotoxic species (e.g., singlet molecular oxygen) responsible for the biological damage.


Photodynamic therapy Radiation transport Diffusion approximation Monte Carlo simulation PDT dosimetry 


  1. 1.
    Raab O. Über die Wirkung fluoreszierender Stoffe and Infusorien. Z Biol. 1900;39:524–46.Google Scholar
  2. 2.
    Dougherty TJ, Kaufman JE, Goldfarb A, Weisshaupt KR, Boyle D, Mittleman A. Photoradiation therapy for the treatment of malignant tumors. Cancer Res. 1978;38:2628–35.PubMedGoogle Scholar
  3. 3.
    Dougherty TJ, Lawrence G, Kaufman JH. Photoradiation in the treatment of recurrent breast carcinoma. J Natl Cancer Inst. 1979;62:231–7.PubMedGoogle Scholar
  4. 4.
    Wilson BC, Patterson MS. The physics of photodynamic therapy. Phys Med Biol. 1986;31:327–60.CrossRefPubMedGoogle Scholar
  5. 5.
    Wilson BC, Patterson MS. The physics, biophysics and technology of photodynamic therapy. Phys Med Biol. 2008;53:R61–109.CrossRefPubMedGoogle Scholar
  6. 6.
    Hecht E. Optics. Reading, MA: Addison-Wesley; 1987.Google Scholar
  7. 7.
    Cheong W, Prahl SA, Welch AJ. A review of the optical properties of biological tissues. IEEE J Quant Electron. 1990;26:2166–85.CrossRefGoogle Scholar
  8. 8.
    van de Hulst HC. Light scattering by small particles. New York: Dover; 1981.Google Scholar
  9. 9.
    Beer A, Lambert J. Einleitung in die höhere Optik. 1854.Google Scholar
  10. 10.
    Huppert TJ. History of diffuse optical spectroscopy of human tissue. In: Madsen SJ, editor. Optical methods and instrumentation in brain imaging and therapy. New York: Springer; 2013. p. 23–56.CrossRefGoogle Scholar
  11. 11.
    Ishimaru A. Wave propagation and scattering in random media. New York: Academic; 1979. Ch 7 and 9.Google Scholar
  12. 12.
    Star WM. Diffusion theory of light transport. In: Welch AJ, van Gemert MJC, editors. Optical thermal response of laser-irradiated tissue. New York: Plenum; 1995. p. 131–206.CrossRefGoogle Scholar
  13. 13.
    Henyey LG, Greenstein JL. Diffuse radiation in the galaxy. Astrophys J. 1941;93:70–83.CrossRefGoogle Scholar
  14. 14.
    Chandrasekhar S. Radiative transfer. London: Oxford University Press; 1950.Google Scholar
  15. 15.
    Rybicki G. The searchlight problem with isotropic scattering. J Quant Spectros Radiat Transf. 1971;11:827–49.CrossRefGoogle Scholar
  16. 16.
    Metropolis N, Ulam S. The Monte Carlo method. J Am Stat Assoc. 1949;44:335–41.CrossRefPubMedGoogle Scholar
  17. 17.
    Wilson BC, Adam G. A Monte Carlo model for the absorption and flux distributions of light in tissue. Med Phys. 1983;10:824–30.CrossRefPubMedGoogle Scholar
  18. 18.
    Flock ST, Patterson MS, Wilson BC, Wyman DR. Monte-Carlo modeling of light-propagation in highly scattering tissues. I. Model predictions and comparison with diffusion theory. IEEE Trans Biomed Eng. 1989;36:1162–8.CrossRefPubMedGoogle Scholar
  19. 19.
    Farrell TJ, Patterson MS, Wilson BC. A diffusion theory model of spatially resolved, steady-state diffuse reflectance for the noninvasive determination of tissue optical properties in vivo. Med Phys. 1992;19:879–88.CrossRefPubMedGoogle Scholar
  20. 20.
    Wang LH, Jacques SL, Zheng LQ. MCML—Monte Carlo modeling of light transport in multilayered tissues. Comput Methods Programs Biomed. 1995;47:131–46.CrossRefPubMedGoogle Scholar
  21. 21.
    Zhu C, Liu Q. Review of Monte Carlo modeling of light transport in tissues. J Biomed Opt. 2013;18:050902.CrossRefGoogle Scholar
  22. 22.
    Colasanti A, Guida G, Kisslinger A, Liuzzi R, Quarto M, Riccio P, Roberti G, Villani F. Multiple processor version of a Monte Carlo code for photon transport in turbid media. Comput Phys Commun. 2000;132:84–93.CrossRefGoogle Scholar
  23. 23.
    Alerstam E, Svensson T, Andersson-Engels S. Parallel computing with graphic processing units for high-speed Monte Carlo simulation of photon migration. J Biomed Opt. 2008;13:060504.CrossRefPubMedGoogle Scholar
  24. 24.
    Lo WCY, Redmond K, Lilge L, Luu J, Chow P, Rose J. Hardware acceleration of a Monte Carlo simulation for photodynamic therapy treatment planning. J Biomed Opt. 2009;14:014019.CrossRefPubMedGoogle Scholar
  25. 25.
    Pratx G, Xing L. Monte Carlo simulation of photon migration in a cloud computing environment with MapReduce. J Biomed Opt. 2011;16:125003.CrossRefPubMedPubMedCentralGoogle Scholar
  26. 26.
    Barajas O, Ballangrud AM, Miller GG, Moore RB, Tulip J. Monte Carlo modeling of angular radiance in tissue phantoms and human prostate: PDT light dosimetry. Phys Med Biol. 1997;42:1675–87.CrossRefPubMedGoogle Scholar
  27. 27.
    Liu B, Farrell TJ, Patterson MS. A dynamic model for ALA-PDT of skin: simulation of temporal and spatial distributions of ground-state oxygen, photosensitizer and singlet oxygen. Phys Med Biol. 2010;55:5913–32.CrossRefPubMedGoogle Scholar
  28. 28.
    Valentine RM, Brown CTA, Moseley H, Ibbotson SH, Wood K. Monte Carlo modeling of in vivo protoporphyrin IX fluorescence and singlet oxygen production during photodynamic therapy for patients presenting with superficial basal cell carcinomas. J Biomed Opt. 2011;16:048002.CrossRefPubMedGoogle Scholar
  29. 29.
    Valentine RM, Wood K, Brown CTA, Ibbotson SH, Moseley H. Monte Carlo simulations for optimal light delivery in photodynamic therapy of non-melanoma skin cancer. Phys Med Biol. 2012;57:6327–45.CrossRefPubMedGoogle Scholar
  30. 30.
    Wyman DR, Patterson MS, Wilson BC. Similarity relations for the interaction parameters in radiation transport. Appl Opt. 1989;28:5243–9.CrossRefPubMedGoogle Scholar
  31. 31.
    Star WM. Light dosimetry in vivo. Phys Med Biol. 1997;42:763–87.CrossRefPubMedGoogle Scholar
  32. 32.
    Hull EL, Foster TH. Steady-state reflectance spectroscopy in the P3 approximation. J Opt Soc Am A. 2001;18:584–99.CrossRefGoogle Scholar
  33. 33.
    Patterson MS, Wilson BC, Wyman DR. The propagation of optical radiation in tissue. 1. Models of radiation transport and their application. Lasers Med Sci. 1991;6:155–68.CrossRefGoogle Scholar
  34. 34.
    Kubelka P, Munk F. Ein beitrag zur optic der farbanstriche. Z Tech Phys. 1931;12:593–601.Google Scholar
  35. 35.
    Kubelka P. New contributions to the optics of intensely light scattering materials. J Opt Soc Am. 1948;38:448–57.CrossRefPubMedGoogle Scholar
  36. 36.
    Prahl SA, van Gemert MJC, Welch AJ. Determining the optical properties of turbid media using the adding-doubling method. Appl Opt. 1993;32:559–68.CrossRefPubMedGoogle Scholar
  37. 37.
    Pickering JW, Prahl SA, van Wieringen N, Beek JF, Sterenborg HJ, van Gemert MJC. Double-integrating-sphere system for measuring the optical properties of tissue. Appl Opt. 1993;32:339–410.CrossRefGoogle Scholar
  38. 38.
    Pickering JW, Bosman S, Posthumus P, Blokland P, Beek JF, van Gemert MJC. Changes in the optical properties (at 632.8 nm) of slowly heated myocardium. Appl Opt. 1993;32:367–71.CrossRefPubMedGoogle Scholar
  39. 39.
    Press WH, Teukolsky SA, Vetterling WT, Flannery BP. Numerical recipes in C: the art of scientific computing. New York: Cambridge University Press; 1992. p. 213–4.Google Scholar
  40. 40.
    Haskell RC, Svaasand LO, Tsay T-T, Feng T-C, McAdams MS, Tromberg BJ. Boundary conditions for the diffusion equation in radiative transfer. J Opt Soc Am A. 1994;11:2727–41.CrossRefGoogle Scholar
  41. 41.
    Kienle A, Patterson MS. Improved solutions of the steady-state and time-resolved diffusion equations or reflectance from a semi-infinite turbid medium. J Opt Soc Am A. 1997;14:246–54.CrossRefGoogle Scholar
  42. 42.
    Hull EL, Nichols MG, Foster TH. Quantitative near-infrared spectroscopy of tissue-simulating phantoms containing erythrocytes. Phys Med Biol. 1998;43:3381–404.CrossRefPubMedGoogle Scholar
  43. 43.
    Kienle A, Patterson MS, Dognitz N, Bays R, Wagnieres G, van den Bergh H. Noninvasive determination of the optical properties of two-layered turbid media. Appl Opt. 1998;37:779–91.CrossRefPubMedGoogle Scholar
  44. 44.
    Driver I, Lowdell CP, Ash DV. In vivo measurements of the optical interaction coefficients of human tumours at 630 nm. Phys Med Biol. 1991;36:805–13.CrossRefPubMedGoogle Scholar
  45. 45.
    Li J, Zhu TC. Determination of in vivo light fluence distribution in a heterogeneous prostate during photodynamic therapy. Phys Med Biol. 2008;53:2103–14.CrossRefPubMedPubMedCentralGoogle Scholar
  46. 46.
    Patterson MS, Chance B, Wilson BC. Time resolved reflectance and transmittance for the non-invasive measurement of tissue optical properties. Appl Opt. 1989;28:2331–6.CrossRefPubMedGoogle Scholar
  47. 47.
    Moulton JD. Diffusion theory modelling of picosecond laser pulse propagation in turbid media. M. Eng. Thesis, McMaster University, Hamilton, ON, Canada; 1990.Google Scholar
  48. 48.
    Madsen SJ, Wilson BC, Patterson MS, Park YD, Jacques SL, Hefetz Y. Experimental tests of a simple diffusion model for the estimation of scattering and absorption coefficients of turbid media from time resolved diffuse reflectance measurements. Appl Opt. 1992;31:3509–17.CrossRefPubMedGoogle Scholar
  49. 49.
    Fishkin J, Gratton E, vandeVen MJ, Mantulin WW. Diffusion of intensity modulated near-infrared light in turbid media. Proc SPIE. 1991;1431:122–35.CrossRefGoogle Scholar
  50. 50.
    O’Leary MA, Boas DA, Chance B, Yodh AG. Refraction of diffuse photon density waves. Phys Rev Lett. 1992;69:2658–61.CrossRefPubMedGoogle Scholar
  51. 51.
    Tromberg BJ, Svaasand LO, Tsay T-T, Haskell RC. Properties of photon density waves in multiple-scattering media. Appl Opt. 1993;32:607–16.CrossRefPubMedGoogle Scholar
  52. 52.
    Patterson MS, Moulton JD, Wilson BC, Berndt KW, Lakowicz JR. Frequency-domain reflectance for the determination of the scattering and absorption properties of tissue. Appl Opt. 1991;30:4474–6.CrossRefPubMedGoogle Scholar
  53. 53.
    Madsen SJ, Anderson ER, Haskell RC, Tromberg BJ. Portable, high-bandwidth frequency-domain photon migration instrument for tissue spectroscopy. Opt Lett. 1994;19:1934–6.CrossRefPubMedGoogle Scholar
  54. 54.
    Pham TH, Coquoz O, Fishkin JB, Anderson E, Tromberg BJ. Broad bandwidth frequency domain instrument for quantitative tissue optical spectroscopy. Rev Sci Inst. 2000;71:2500–13.CrossRefGoogle Scholar
  55. 55.
    Redmond RW, Gamlin JN. A compilation of singlet oxygen yields from biologically relevant molecules. Photochem Photobiol. 1999;70:391–475.CrossRefPubMedGoogle Scholar
  56. 56.
    Weishaupt KR, Gomer CJ, Dougherty TJ. Identification of singlet oxygen as cytotoxic agent in photoinactivation of a murine tumor. Cancer Res. 1976;36:2326–9.PubMedGoogle Scholar
  57. 57.
    Niedre M, Patterson MS, Wilson BC. Direct near-infrared luminescence detection of singlet oxygen generated by photodynamic therapy in cells in vitro and tissues in vivo. Photochem Photobiol. 2002;75:382–91.CrossRefPubMedGoogle Scholar
  58. 58.
    Foote CS. Definition of type-I and type-II photosensitized oxidation. Photochem Photobiol. 1991;54:659.CrossRefPubMedGoogle Scholar
  59. 59.
    Farrell TJ, Wilson BC, Patterson MS, Olivo MC. Comparison of the in vivo photodynamic threshold dose for Photofrin, mono- and tetrasulfonated aluminum phthalocyanine using a rat liver model. Photochem Photobiol. 1998;68:394–9.CrossRefPubMedGoogle Scholar
  60. 60.
    Wilson BC, Patterson MS, Lilge L. Implicit and explicit dosimetry in photodynamic therapy: a new paradigm. Lasers Med Sci. 1997;12:182–99.CrossRefGoogle Scholar
  61. 61.
    Weersink RA, Bogaards A, Gertner M, Davidson SR, Zhang K, Netchev G, Trachtenberg J, Wilson BC. Techniques for delivery and monitoring of TOOKAD (WST09)-mediated photodynamic therapy of the prostate: clinical experience and practicalities. J Photochem Photobiol B. 2005;79:211–22.CrossRefPubMedGoogle Scholar
  62. 62.
    Thompson MS, Johansson A, Johansson T, Andersson-Engels S, Svanberg S, Bendsoe N, Svanberg K. Clinical system for interstitial photodynamic therapy with combined on-line dosimetry measurements. Appl Opt. 2005;44:4023–31.CrossRefPubMedGoogle Scholar
  63. 63.
    Zhu TC, Finlay JC, Hahn SM. Determination of the distribution of light, optical properties, drug concentration, and tissue oxygenation in vivo in human prostate during motexafin lutetium-mediated photodynamic therapy. J Photochem Photobiol B. 2005;79:231–41.CrossRefPubMedGoogle Scholar
  64. 64.
    Zeng H, Korbelik M, McLean DI, MacAulay C, Lui H. Monitoring photoproduct formation and photobleaching by fluorescence spectroscopy has the potential to improve PDT dosimetry with a verteporfin-like photosensitizer. Photochem Photobiol. 2002;75:398–405.CrossRefPubMedGoogle Scholar
  65. 65.
    Georgakoudi I, Nichols MG, Foster TH. The mechanism of Photofrin photobleaching and its consequences for photodynamic dosimetry. Photochem Photobiol. 1997;65:135–44.CrossRefPubMedGoogle Scholar
  66. 66.
    Robinson DJ, de Bruijn HS, van der Veen N, Stringer MR, Brown SB, Star WM. Fluorescence photobleaching of ALA-induced protoporphyrin IX during photodynamic therapy of normal hairless mouse skin: the effect of light dose and irradiance and the resulting biological effect. Photochem Photobiol. 1998;67:140–9.CrossRefPubMedGoogle Scholar
  67. 67.
    Diamond KR, Patterson MS, Farrell TJ. Quantification of fluorophore concentration in tissue-simulating media by fluorescence measurements with a single optical fiber. Appl Opt. 2003;42:2436–42.CrossRefPubMedGoogle Scholar
  68. 68.
    Pogue BW, Burke G. Fiber-optic bundle design for quantitative fluorescence measurement from tissue. Appl Opt. 1998;37:7429–36.CrossRefPubMedGoogle Scholar
  69. 69.
    Farrell TJ, Patterson MS, Hayward JE, Wilson BC, Beck ER. A CCD and neural network based instrument for the non-invasive determination of tissue optical properties in vivo. Proc SPIE. 1994;2135:117–28.CrossRefGoogle Scholar
  70. 70.
    Synytsya A, Kral V, Matejka P, Pouckova P, Volka K, Sessler JL. Biodistribution assessment of a lutetium (III) texaphyrin analogue in tumor-bearing mice using NIR Fourier-transform Raman spectroscopy. Photochem Photobiol. 2004;79:453–60.CrossRefPubMedGoogle Scholar
  71. 71.
    Buerk DG. Measuring tissue PO2 with microelectrodes. Methods Enzymol. 2004;381:665–90.CrossRefPubMedGoogle Scholar
  72. 72.
    Papkovsky DB. Methods in optical oxygen sensing: protocols and critical analyses. Methods Enzymol. 2004;381:715–35.CrossRefPubMedGoogle Scholar
  73. 73.
    Braun RD, Lanzen JL, Snyder SA, Dewhirst MW. Comparison of tumor and normal tissue oxygen tension measurements using OxyLite or microelectrodes in rodents. Am J Physiol Heart Circ Physiol. 2001;280:H2533–44.PubMedGoogle Scholar
  74. 74.
    Dysart JS, Patterson MS. Characterization of Photofrin photobleaching for singlet oxygen dose estimation during photodynamic therapy of MLL cells in vitro. Phys Med Biol. 2005;50:2597–616.CrossRefPubMedGoogle Scholar
  75. 75.
    Jarvi MT, Patterson MS, Wilson BC. Insights into photodynamic therapy dosimetry: simultaneous singlet oxygen luminescence and photosensitizer photobleaching measurements. Biophys J. 2012;102:661–71.CrossRefPubMedPubMedCentralGoogle Scholar
  76. 76.
    Finlay JC, Mitra S, Patterson MS, Foster TH. Photobleaching kinetics of Photofrin in vivo and in multicell tumor spheroids indicate two simultaneous bleaching mechanisms. Phys Med Biol. 2004;49:4837–60.CrossRefPubMedGoogle Scholar
  77. 77.
    Dysart JS, Patterson MS. Photobleaching kinetics, photoproduct formation, and dose estimation during ALA induced PpIX PDT of MLL cells under well oxygenated and hypoxic conditions. Photochem Photobiol Sci. 2006;5:73–81.CrossRefPubMedGoogle Scholar
  78. 78.
    Rodgers MAJ. On the problem involved in detecting the luminescence from singlet oxygen in biological specimens. J Photochem Photobiol B Biol. 1988;1:371–3.CrossRefGoogle Scholar
  79. 79.
    Patterson MS, Madsen SJ, Wilson BC. Experimental tests of the feasibility of singlet oxygen luminescence monitoring in vivo during photodynamic therapy. J Photochem Photobiol. 1990;5:69–84.CrossRefGoogle Scholar
  80. 80.
    Gorman AA, Rodgers MAJ. Current perspectives of singlet oxygen detection in biological environments. J Photochem Photobiol B Biol. 1992;14:159–76.CrossRefGoogle Scholar
  81. 81.
    Hirano T, Kohno E, Nishiwaki M. Detection of near infrared emission from singlet oxygen in PDT with an experimental tumor bearing mouse. J Jpn Soc Laser Surg Med. 2002;22:99–108.Google Scholar
  82. 82.
    Niedre MJ, Secord AJ, Patterson MS, Wilson BC. In vitro tests of the validity of singlet oxygen luminescence measurements as a dose metric in photodynamic therapy. Cancer Res. 2003;63:7986–94.PubMedGoogle Scholar
  83. 83.
    Niedre MJ, Yu CS, Patterson MS, Wilson BC. Singlet oxygen luminescence as an in vivo photodynamic therapy dose metric: validation in normal mouse skin with topical amino-levulinic acid. Br J Cancer. 2005;92:298–304.PubMedPubMedCentralGoogle Scholar
  84. 84.
    Jimenez-Banzo A, Ragas X, et al. Time-resolved methods in biophysics. 7. Photon counting vs. analog time-resolved singlet oxygen phosphorescence detection. Photochem Photobiol Sci. 2008;7:1003–10.CrossRefPubMedGoogle Scholar
  85. 85.
    Luna MC, Wong S, Gomer CJ. Photodynamic therapy mediated induction of early response genes. Cancer Res. 1994;54:1374–80.PubMedGoogle Scholar
  86. 86.
    Oleinick NL, Evans HH. The photobiology of photodynamic therapy: cellular targets and mechanisms. Radiat Res. 1998;150:S146–56.CrossRefPubMedGoogle Scholar
  87. 87.
    Veenhuizen RB, Stewart FA. The importance of fluence rate in photodynamic therapy—is there a parallel with ionizing radiation dose-rate effects. Radiother Oncol. 1995;37:131–5.CrossRefPubMedGoogle Scholar
  88. 88.
    Sterenborg HJCM, vanGemert MJC. Photodynamic therapy with pulsed light sources: a theoretical analysis. Phys Med Biol. 1996;41:835–49.CrossRefPubMedGoogle Scholar
  89. 89.
    Tromberg BJ, Orenstein A, Kimel S, Barker SJ, Hyatt J, Nelson JS, Berns MW. In vivo tumor oxygen-tension measurements for the evaluation of the efficiency of photodynamic therapy. Photochem Photobiol. 1990;52:375–85.CrossRefPubMedGoogle Scholar
  90. 90.
    Foster TH, Murant RS, Bryant RG, Knox RS, Gibson SL, Hilf R. Oxygen consumption and diffusion effects in photodynamic therapy. Radiat Res. 1991;126:296–303.CrossRefPubMedGoogle Scholar
  91. 91.
    Foster TH, Gao L. Dosimetry in photodynamic therapy—oxygen and the critical importance of capillary density. Radiat Res. 1992;130:379–83.CrossRefPubMedGoogle Scholar
  92. 92.
    Busch TM. Local physiological changes during photodynamic therapy. Lasers Surg Med. 2006;38:494–9.CrossRefPubMedGoogle Scholar
  93. 93.
    Chen Q, Chen H, Hetzel FW. Tumor oxygenation changes post-photodynamic therapy. Photochem Photobiol. 1996;63:128–31.CrossRefPubMedGoogle Scholar
  94. 94.
    Chen Q, Huang Z, Chen H, Shapiro H, Beckers J, Hetzel FW. Improvement of tumor response by manipulation of tumor oxygenation during photodynamic therapy. Photochem Photobiol. 2002;76:197–203.CrossRefPubMedGoogle Scholar
  95. 95.
    Henderson BW, et al. Photofrin photodynamic therapy can significantly deplete or preserve oxygenation in human basal cell carcinomas during treatment depending on fluence rate. Cancer Res. 2000;60:525–9.PubMedGoogle Scholar
  96. 96.
    Coutier S, Bezdetnaya LN, Foster TH, Parache RM, Guillemin F. Effect of irradiation fluence rate on the efficacy of photodynamic therapy and tumor oxygenation in meta-tetra(hydroxyphenyl)chlorine (mTHPC)-sensitized HT29 xenografts in nude mice. Radiat Res. 2002;158:339–45.CrossRefPubMedGoogle Scholar
  97. 97.
    Henderson BW, Gollnick SO, Snyder JW, Busch TM, Kousis PC, Cheney RT, Morgan J. Choice of oxygen-conserving treatment regimen determines the inflammatory response and outcome of photodynamic therapy in tumors. Cancer Res. 2004;64:2120–6.CrossRefPubMedGoogle Scholar
  98. 98.
    Bisland SK, Lilge L, Lin A, Rusnov R, Wilson BC. Metronomic photodynamic therapy as a new paradigm for photodynamic therapy: rationale and pre-clinical evaluation of technical feasibility for treating malignant brain tumors. Photochem Photobiol. 2004;80:2–30.Google Scholar
  99. 99.
    Madsen SJ, Sun C-H, Tromberg BJ, Hirschberg H. Development of a novel indwelling balloon applicator for optimizing light delivery in photodynamic therapy. Lasers Surg Med. 2001;29:406–12.CrossRefPubMedGoogle Scholar
  100. 100.
    Madsen SJ, Sun C-H, Tromberg BJ, Hirschberg H. Repetitive 5-aminolevulinic acid-mediated photodynamic therapy on human glioma spheroids. J Neurooncol. 2003;62:243–50.CrossRefPubMedGoogle Scholar
  101. 101.
    Gemmell NR, McCarthy A, Liu B, Tanner MG, Dorenbos SD, Zwiller V, Patterson MS, Buller GS, Wilson BC, Hadfield RH. Singlet oxygen luminescence detection with a fiber-coupled superconducting nanowire single-photon detector. Opt Express. 2013;21:5005–13.CrossRefPubMedGoogle Scholar
  102. 102.
    Du KL, Mick R, Busch TM, Zhu TC, Finlay JC, Yu G, Yodh AG, Malkowicz SB, Smith D, Whittington R, Stripp D, Hahn SM. Preliminary results of interstitial motexafin lutetium-mediated PDT for prostate cancer. Lasers Surg Med. 2006;38:427–34.CrossRefGoogle Scholar

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© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Department of Health Physics and Diagnostic SciencesUniversity of Nevada, Las VegasLas VegasUSA

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