Estimation of depth of fluorescing lesions in tissue from changes in fluorescence spectra

Swartling, Johannes; Bengtsson, Daniel; Terike, Khaled; Svensson, Johannes; Andersson‐Engels, Stefan

doi:10.1117/12.590145

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…Fluorescence registered at different emission wavelengths can help to evaluate the distribution of fluorophores [11]. It was also shown [12][13][14] that, for fluorophores with a wide emission spectrum, the ratio of fluorescence signals registered at different emission wavelengths can serve as a criterion of a fluorescent object localization depth. However, most PSs exhibit narrowband emission spectra (usually below 100 nm) that limit the possibilities of this approach in the evaluation of PS penetration depth.…”

Section: Introductionmentioning

confidence: 99%

Estimation of chlorin-based photosensitizer penetration depth prior to photodynamic therapy procedure with dual-wavelength fluorescence imaging

Khilov¹,

Kirillin²,

Loginova³

et al. 2018

Laser Phys. Lett.

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Photodynamic therapy (PDT) is a modern treatment technique employed as an antitumor, antibacterial, or rejuvenation aid in superficial tissues. The use of fluorescent photosensitizers (PSs) implements the principles of theranostics when the applied medical agents serve both for diagnostic and treatment purposes. For efficient PDT performance it is important to evaluate the in-depth distribution of PSs in tissues prior to irradiation. Fluorescence imaging is a common technique to monitor the distribution of PSs in tissue. However, in-depth resolution is challenging. Chlorin-based PSs reveal two narrow fluorescence excitation peaks at 405 and 660 nm providing additional diagnostic opportunities. We demonstrate that the ratio of the fluorescence signals upon excitation at these wavelengths provides the evaluation of the PS penetration depth after topical application. The study is based on Monte Carlo simulations that are in agreement with phantom experiments. The effect of medium optical properties on the depth-dependent fluorescence signal ratio is analyzed.

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Section: Introductionmentioning

confidence: 99%

Estimation of chlorin-based photosensitizer penetration depth prior to photodynamic therapy procedure with dual-wavelength fluorescence imaging

Khilov¹,

Kirillin²,

Loginova³

et al. 2018

Laser Phys. Lett.

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“…Estimation of PS penetration depth. Estimation of PS penetration depth was carried out using the approach previously proposed in [17,18]. It is based on the development of numerical model for fluorescent response of biological tissue in the presence of PS.…”

Section: Experimental Investigationsmentioning

confidence: 99%

“…Simultaneous use of different PS absorption bands provides additional opportunities for both monitoring and performance of a PDT procedure. In particular, the registration of the fluorescence signal at different excitation wavelengths allows for noninvasive evaluation of PS penetration depth into tissues [17,18].…”

mentioning

confidence: 99%

Two-Wavelength Fluorescence Monitoring and Planning of Photodynamic Therapy

Khilov¹,

Loginova²,

Сергеева³

et al. 2017

Sovrem Tehnol Med

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The aim of the study is to develop approaches for fluorescence monitoring and planning of photodynamic therapy employing chlorine series photosensitizers. Materials and Methods. The study included numerical simulations and experiments with optical agar phantoms of biotissue and human skin in vivo. Fluorescence imaging was used as a method of optical monitoring. Chlorine series photosensitizer Photoditazin (Veta Grand, Russia) was employed. Numerical simulation of light propagation was performed with Monte-Carlo technique for a multilayer skin model. Results. It was demonstrated that in the case of two-wavelength fluorescence monitoring of photosensitizer penetration into the tissue the ratio of fluorescence signals excited at wavelengths of 405 and 660 nm can be used as a characteristic of photosensitizer penetration depth in biological tissue. The results of numerical simulations are in good agreement with the results of model experiments on agar phantoms and pilot in vivo experiment. Radiant exposure and absorbed light dose maps at the wavelengths of 405 and 660 nm were calculated employing Monte-Carlo technique; the dependencies of the characteristic dose values on the optical properties of the medium were analyzed. Conclusion. Two-wave fluorescence imaging technique allows for non-invasive estimation of chlorine series photosensitizer penetration depth into the biotissue after topical application, while numerical simulation by Monte-Carlo method allows for more accurate choice of the light exposure dose for photodynamic therapy depending on optical properties of the tissue and the radiation wavelength.

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“…Therefore, the diffusive optical imaging requires an interpretation on measurements performed from sources and detectors spaced over the boundaries of the interrogated tissue. In this way, relevant parameters linked to the localization of fluorescent inclusions in homogeneous media have been reported by different groups [10][11][12][13][14][15][16][17][18][19]. Optimizing analysis of these types of data is an area of very active research in order to improve depth sensitivity [20][21][22][23][24] and quantify fluorescence rate [25,26] in the human brain.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved optical fluorescence spectroscopy of heterogeneous turbid media with special emphasis on brain tissue structures including diseased regions: A sensitivity analysis

Vaudelle

L’Huillier

2013

Optics Communications

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. b s t r a c tFluorescence-enhanced optical imaging based on near-infrared light provides a promising tool to differentiate diseased lesions from normal tissue. However, the measurement sensitivity of the fluorescence signals acquired at the output surface of the tissue is greatly influenced by the tissue structure, the optical properties, the location and the size of the target. In this paper, we present a numerical model based on the Monte Carlo method that allows to simulate time-resolved reflectance signals acquired on the surface of the scalp of a human head model bearing a fluorescent diseased region (tumor, glioma). The influence of tumor depth, tumor size and tumor shape evolution on the computed signals are analyzed by taking into account the multi-layered tissue structure. The simulations show that the mean-time-of-flight and the difference between two mean-times acquired at two source-detector distances are both relevant to this problem type. Furthermore, the simulations suggest that the use of the difference between mean-flight-times may be interesting to probe scattering changes that occur in the cerebrospinal fluid (CSF).

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Estimation of depth of fluorescing lesions in tissue from changes in fluorescence spectra

Cited by 3 publications

References 9 publications

Estimation of chlorin-based photosensitizer penetration depth prior to photodynamic therapy procedure with dual-wavelength fluorescence imaging

Estimation of chlorin-based photosensitizer penetration depth prior to photodynamic therapy procedure with dual-wavelength fluorescence imaging

Two-Wavelength Fluorescence Monitoring and Planning of Photodynamic Therapy

Time-resolved optical fluorescence spectroscopy of heterogeneous turbid media with special emphasis on brain tissue structures including diseased regions: A sensitivity analysis

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