Principles of fluorescence laser tomography of strongly scattering media

Lyubimov, V. V.

doi:10.1134/1.626793

Cited by 10 publications

(12 citation statements)

References 3 publications

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“…We begin with a number of simplifying assumptions. First, in case of early arriving photons, the time dependence φ e ( r , t ) is dominated by the factor exp(−| r | 2 /4 D e c e t ) 63 and then for source function (5) we can use its asymptotic approximation 67 (See Appendix A). Second, we will assume that fluorophore is spread within a local region of a homogeneous object and hence, in first approximation, we can neglect the attenuation of φ e ( r , t ) due to exiting radiation absorption by the fluorophore.…”

Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

“…With Equations (7) and (8), the equation relating solutions φ e ( r , t ) and φ f ( r , t ) is written as 63

φ^{f} ((), boldr, t) = c^{f} γ \int_{t_{s}}^{t} d t^{'} \int_{V} \frac{μ_{af} ((), {boldr}^{'}) \cdot 4 D^{e} c^{e} {t^{'}}^{2}}{τ {|r^{'}|}^{2} + 4 D^{e} c^{e} {t^{'}}^{2}} φ^{e} ((),, {boldr}^{'}, t^{'}) G^{f} ((),, boldr - r^{'}, t - t^{'}) d^{3} r^{'},

where G f ( r − r ′ , t − t ′ ) is the Green function of diffusion Equation (7) for fluorescence.…”

Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

“…For further consideration we need to decide which measurement data we will use for fluorescent image reconstruction. We will follow the study 63 where Lyubimov was among the first to suggest using the ratio of fluorescence and exiting radiation fluxes measured on the boundary of the object for a selected time‐gating delay of receiver,

g ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t_{d}) = \frac{{(|, Γ^{f} ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t))}_{t = t_{d}}}{{(|, Γ^{e} ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t))}_{t = t_{d}}},

where Γ e ( r s , t s , r d , t ) and Γ f ( r s , t s , r d , t ) are temporal responses TPSF and TFR, respectively, and t d is the time‐gating delay of receiver (or time gate). The measurement datum g ( r s , t s , r d , t d ) will hereafter be referred to as time‐resolved normalized (TRN) datum.…”

Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

“…In our further consideration we will follow in part an approach presented many years ago by Dr. Vladimir Lyubimov. 63 Lyubimov dealt with the photon average trajectory method -an approximate method of DOT and FMT, which solves the inverse problem in real time. [63][64][65][66] It reduces the problem to the inversion of the integral equation with integration over the photon average trajectory.…”

Section: Fundamental Equation Of Ep-fmtmentioning

confidence: 99%

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Early‐photon reflectance fluorescence molecular tomography for small animal imaging: Mathematical model and numerical experiment

Konovalov

Vlasov

Uglov

2020

Numer Methods Biomed Eng

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The paper presents an original approach to time‐domain reflectance fluorescence molecular tomography (FMT) of small animals. It is based on the use of early arriving photons and state‐of‐the‐art compressed‐sensing‐like reconstruction algorithms and aims to improve the spatial resolution of fluorescent images. We deduce the fundamental equation that models the imaging operator and derive analytical representations for the sensitivity functions which are responsible for the reconstruction of the fluorophore absorption coefficient. The idea of fluorescence lifetime tomography with our approach is also discussed. We conduct a numerical experiment on 3D reconstruction of box phantoms with spherical fluorescent inclusions of small diameters. For modeling measurement data and constructing the sensitivity matrix we assume a virtual fluorescence tomograph with a scanning fiber probe that illuminates and collects light in reflectance geometry. It provides for large source‐receiver separations which correspond to the macroscopic regime. Two compressed‐sensing‐like reconstruction algorithms are used to solve the inverse problem. These are the algebraic reconstruction technique with total variation regularization and our modification of the fast iterative shrinkage‐thresholding algorithm. Results of our numerical experiment show that our approach is capable of achieving as good spatial resolution as 0.2 mm and even better at depths to 9 mm inclusive.

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Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

“…With Equations (7) and (8), the equation relating solutions φ e ( r , t ) and φ f ( r , t ) is written as 63

φ^{f} ((), boldr, t) = c^{f} γ \int_{t_{s}}^{t} d t^{'} \int_{V} \frac{μ_{af} ((), {boldr}^{'}) \cdot 4 D^{e} c^{e} {t^{'}}^{2}}{τ {|r^{'}|}^{2} + 4 D^{e} c^{e} {t^{'}}^{2}} φ^{e} ((),, {boldr}^{'}, t^{'}) G^{f} ((),, boldr - r^{'}, t - t^{'}) d^{3} r^{'},

where G f ( r − r ′ , t − t ′ ) is the Green function of diffusion Equation (7) for fluorescence.…”

Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

g ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t_{d}) = \frac{{(|, Γ^{f} ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t))}_{t = t_{d}}}{{(|, Γ^{e} ((),,,, {boldr}_{s}, t_{s}, {boldr}_{d}, t))}_{t = t_{d}}},

Section: Mathematical Model Of the Ep‐fmt Forward Problemmentioning

confidence: 99%

Section: Fundamental Equation Of Ep-fmtmentioning

confidence: 99%

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Early‐photon reflectance fluorescence molecular tomography for small animal imaging: Mathematical model and numerical experiment

Konovalov

Vlasov

Uglov

2020

Numer Methods Biomed Eng

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“…In this case, the role of the time-resolved optical projection (23) can be played by the ratio of fluorescence and incident radiation fluxes, measured for individual counts of temporal fluorescence response and the TPSF, respectively [282].…”

Section: Perturbation Semianalytic Methodsmentioning

confidence: 99%

Diffuse optical mammotomography: state-of-the-art and prospects

Konovalov

Genina

Bashkatov

2016

JBPE

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Abstract:The principles of diffuse optical tomography (DOT) of tissues are presented. The DOT capabilities as a method of breast cancer diagnostics are analysed. The state-ofthe-art of the DOT instrumentation and methodological base in application to solving the mammography problems are described. The significant contribution of Russian scientists to the development of the DOT methodology is emphasised. Basing on the results of the analysis, the authors expect the possibility of soonest entry of diffuse optical mammotomographs to the market of medical imaging instrumentation, and the capability of Russian researchers to take part in the competition for this market. © 2016 Journal of Biomedical Photonics & Engineering.Key words: diffuse optical tomography, breast, optical and functional parameters, methods of determining optical parameters, methods of image reconstruction, perturbation model of reconstruction, temporal point spread function, spatial resolution, reconstruction time. University Press, Cambridge (2016). 7. S. R. Arridge, and M. Schweiger, "Inverse methods for optical tomography," in Information Processing in Medical Imaging, H.H. Barrett (ed.), Springer-Verlag, Flagstaff, 259-277 (1993). 8. J. C. Hebden, S. R. Arridge, and D. T. Delpy, "Optical imaging in medicine: I. Experimental techniques,"Phys. Med. Biol. 42, 825-840 (1997). 9. S. R. Arridge, and J. C. Hebden, "Optical imaging in medicine: II. Modelling and reconstruction," Phys. Med. Biol. 42, 841-853 (1997). 10. B. B. Das, F. Liu, and R. R. Alfano, "Time-resolved fluorescence and photon migration studies in biomedical and random media," Rep. Prog. Phys. 60, 227-292 (1997). 11. K. Michielsen, H. De'Raedt, J. Przeslawski, and N. Garcia, "Computer simulation of time-resolved optical imaging of objects hidden in turbid media," Phys. Rep. 304, 89-144 (1998). 12. S. R. Arridge, "Optical tomography in medical imaging," Inverse Problems 15, R41-R93 (1999). Darzi, "Diffuse optical imaging of the healthy and diseased breast: a systematic review," Breast Cancer Research and Treatment 108, 9-22 (2008). 19. S. L. Jacques, and B. W. Pogue, "Tutorial on diffuse light transport," J. Biomed. Opt. 13, 041302 (2008 Biol. 361, 171-179 (1994). 31. A. Yodh, and B. Chance, "Spectroscopy and imaging with diffusing light," Phys. Today 48, 34-40 (1995). 32. J. C. Hebden, S. R. Arridge, "Imaging through scattering media by the use of an analytical model of perturbation amplitudes in the time domain," Appl. Opt. 35, 6788-6796 (1996). 33. K. D. Paulsen, and H. Jiang, "Enhanced frequency-domain optical image reconstruction in tissues through total-variation minimization," Appl. Opt. 35, 3447-3458 (1996). 34. R. J. Grable, "Optical tomography improves mammography," Laser Focus World 32, 113-118 (1996). 35. V. V. Lyubimov, "The physical foundation of the strongly scattering media laser tomography," Proc. SPIE 2769SPIE , 107-110 (1996. 36. V. V. Lyubimov, "Optical tomography of highly scattering media by using the first transmitted photons of ultrashort pulses," Optics a...

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Imaging of QDs-labeled tumors in small animals by fluorescence diffuse tomography

Turchin¹,

Balalaeva²,

Васильев³

et al. 2005

Laser Phys. Lett.

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Quantum dots (QD) are a new class of fluorescence labels with properties and biomedical applications that are not available with traditional organic dyes and fluorescent proteins. The unique optical properties of QDs (high absorption, quantum yield and emission spanning to near IR) make them attractive as in vivo markers for deep-tissue imaging. Different types of optical tomography allow imaging of fluorescent-labeled tumors located deep in human or animal tissue. In this work, preliminary results of the fluorescent diffuse tomography (FDT) method in application to CdTe/CdSe-core/shell fluorescing nanocrystals are reported. In our experiments we utilized low-frequency amplitude modulation (1 kHz) of the second harmonic of Nd:YAG laser (532 nm). The transilluminative configuration was used in the setup. Results of post mortem experiments with capsules containing QDs placed into esophagus of small animals to simulate labeled tumor are shown. An algorithm of processing fluorescent image based on calculating zero of maximum curvature has been applied to detect fluorescent inclusions boundaries on the image. This work demonstrates potential capabilities of the FDT method for imaging of deep fluorescent tumors in human tissue or animal models of human cancer.Intensity, a.u.

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Principles of fluorescence laser tomography of strongly scattering media

Cited by 10 publications

References 3 publications

Early‐photon reflectance fluorescence molecular tomography for small animal imaging: Mathematical model and numerical experiment

Early‐photon reflectance fluorescence molecular tomography for small animal imaging: Mathematical model and numerical experiment

Diffuse optical mammotomography: state-of-the-art and prospects

Imaging of QDs-labeled tumors in small animals by fluorescence diffuse tomography

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