Photodynamic tumor therapy and on-line fluorescence spectroscopy after ALA administration using 633-nm light as therapeutic and fluorescence excitation radiation

Koenig, Karsten; Kienle, Alwin; Boehncke, Wolf‐Henning; Kaufmann, Roland; Rueck, Angelika C.; Meier, Thomas; Steiner, Rudolf

doi:10.1117/12.177511

Cited by 25 publications

(5 citation statements)

References 1 publication

(1 reference statement)

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“…No weighting schemes were applied. The calculation of the fluorescence light propagation was implemented directly as described earlier 25 . Thus, convolution algorithms were avoided.…”

Section: Theorymentioning

confidence: 99%

Analytical solutions of the radiative transport equation for turbid and fluorescent layered media

Liemert

Reitzle

Kienle

2017

Sci Rep

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Accurate and efficient solutions of the three dimensional radiative transport equation were derived in all domains for the case of layered scattering media. Index mismatched boundary conditions based on Fresnel’s equations were implemented. Arbitrary rotationally symmetric phase functions can be applied to characterize the scattering in the turbid media. Solutions were derived for an obliquely incident beam having arbitrary spatial profiles. The derived solutions were successfully validated with Monte Carlo simulations and partly compared with analytical solutions of the diffusion equation.

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“…No weighting schemes were applied. The calculation of the fluorescence light propagation was implemented directly as described earlier 25 . Thus, convolution algorithms were avoided.…”

Section: Theorymentioning

confidence: 99%

Analytical solutions of the radiative transport equation for turbid and fluorescent layered media

Liemert

Reitzle

Kienle

2017

Sci Rep

Self Cite

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“…For both excitations, the maximum fluorescence intensity occurs at 5 J/cm2, after which the photodegradation of the fluorophore is observed. Photoproducts are also susceptible to photobleaching 21 , 24 . Thus, the decrease in the fluorescence intensity of the pellet observed around 10 J/cm2 exposure could be caused by both PpIX and photoproduct photobleaching.…”

Section: Resultsmentioning

confidence: 99%

“…Photoproducts are also susceptible to photobleaching. 21 , 24 Thus, the decrease in the fluorescence intensity of the pellet observed around

exposure could be caused by both PpIX and photoproduct photobleaching.…”

Section: Resultsmentioning

confidence: 99%

“…The PpIX fluorescence spectrum shape and its maximum peak at 633 nm obtained in our study are consistent with other studies. [20][21][22]24,30 The higher initial fluorescence intensity of I G than I B observed in the PpIX solution [Fig. 3(a)] is expected because the absorption band of PpIX is higher at 505 nm than at 450 nm.…”

Section: Discussionmentioning

confidence: 96%

“…Light irradiation of PpIX in solution, in vitro , and in vivo forms photoproducts having absorption bands in the red spectral region 18 – 21 The dominant photoproduct formed from PpIX irradiation is photoprotoporphyrin (Ppp). Ppp, in itself, is a fluorophore and emits fluorescence when excited 22 .…”

Section: Introductionmentioning

confidence: 99%

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Increased fluorescence observation intensity during the photodynamic diagnosis of deeply located tumors by fluorescence photoswitching of protoporphyrin IX

et al. 2023

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Significance: Photobleaching of the photosensitizer reduces fluorescence observation time and the intensity of fluorescence emitted for tumor detection during 5-aminolevulinic acid-based photodynamic diagnosis.Aim: This study aims to utilize the concept of fluorescence photoswitching, which uses the fluorescence emission from photosensitizer excitation followed by the simultaneous excitation of the photosensitizer and its photoproduct to increase the fluorescence detection intensity during PDD of deeply located tumors. Approach:The fluorescence photobleaching of protoporphyrin IX (PpIX) and the formation of its photoproduct, photoprotoporhyrin (Ppp), caused by exposure to 505 nm light were investigated in solution, ex vivo, and in vivo, and the fluorescence photoswitching was analyzed. The fluorescence observations of PpIX and Ppp were performed with 505 and 450 or 455 nm excitation, respectively, which is the suited wavelength for the primary excitation of each fluorophore.Results: Fluorescence photoswitching was observed in all forms of PpIX investigated, and the fluorescence photoswitching time, fluorescence intensity relative to the initial PpIX and Ppp intensity, and fluorescence intensity relative to PpIX after photobleaching were obtained. The dependence of the fluorescence photoswitching time and intensity on the irradiation power density was noted. A fluorescence intensity increase between 1.6 and 3.9 times was achieved with simultaneous excitation of PpIX and Ppp after fluorescence photoswitching, compared with the excitation of PpIX alone. Conclusions:We have demonstrated the potential of fluorescence photoswitching for the improvement of the fluorescence observation intensity for the PDD of deeply located tumors.

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Photodynamic effects on human and chicken erythrocytes studied with microirradiation and confocal laser scanning microscopy

1996

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Photodynamic tumor therapy and on-line fluorescence spectroscopy after ALA administration using 633-nm light as therapeutic and fluorescence excitation radiation

Cited by 25 publications

References 1 publication

Analytical solutions of the radiative transport equation for turbid and fluorescent layered media

Analytical solutions of the radiative transport equation for turbid and fluorescent layered media

Increased fluorescence observation intensity during the photodynamic diagnosis of deeply located tumors by fluorescence photoswitching of protoporphyrin IX

Photodynamic effects on human and chicken erythrocytes studied with microirradiation and confocal laser scanning microscopy

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