&lt;title&gt;Optical properties of human stomach mucosa in the spectral range from 400 to 2000 nm&lt;/title&gt;

Bashkatov, Alexey N.; Genina, Elina A.; Kochubey, Vyacheslav I.; Gavrilova, Anna A.; Капралов, С. В.; Grishaev, Veniamin A.; Tuchin, Valery V.

doi:10.1117/12.740966

Cited by 1 publication

(2 citation statements)

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“…This depth is within the depth suitable for the green light PDD reported 11 . The similarity between the light penetration depth in the human gastric mucosa and porcine gastric mucosa has been confirmed 11 , 35 . Our ex vivo investigation was performed using a similar porcine gastric mucosa as Ihara et al 11 .…”

Section: Discussionsupporting

confidence: 73%

“…11 The similarity between the light penetration depth in the human gastric mucosa and porcine gastric mucosa has been confirmed. 11,35 Our ex vivo investigation was performed using a similar porcine gastric mucosa as Ihara et al 11 With that stated, it is safe to follow the clinical applications reported in their study. Our result shows that the successive use of 505 nm followed by 450 nm excitation is advantageous for the ALA-PDD of deeply located lesions.…”

Section: Discussionmentioning

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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