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Ting W, Chong Y, Xu J, Huang J, Yu N, Liu Z. Treatment of Keloids Using Plasma Skin Regeneration Combined with Radiation Therapy Under the Evaluation of Patient and Observer Scar Assessment Scale. Clin Cosmet Investig Dermatol 2021; 14:981-989. [PMID: 34385829 PMCID: PMC8353170 DOI: 10.2147/ccid.s321348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 07/21/2021] [Indexed: 02/03/2023]
Abstract
Purpose Keloids are caused by uncontrolled excessive proliferation of fibrous tissue. Multiple treatment strategies including steroid injection, surgical excision, laser therapy and radiation therapy have been reported. Few studies have evaluated the performance of plasma skin regeneration (PSR) in the treatment of keloid. This study aimed to evaluate the effectiveness of PSR combined with radiation therapy for keloids on different body parts. Patients and Methods A total of 71 patients with 98 keloids were enrolled in this study. Keloids <4 mm thick underwent single-dose PSR, while keloids ≥4 mm thick were administered compound betamethasone injection beforehand. Radiation therapy was administered after 24 hours and again 7 days later after PSR. The outcome was evaluated using the patient and observer scar assessment scale at 12 months post-treatment. Results Patient-reported average scores for all keloids significantly decreased from 35.05±9.94 to 21.84±7.04 (p < 0.05). Keloids on face and neck, chest, and back responded better than those on shoulders and limbs. The recurrence rate was observed to be 15.3% (15 out of 98). Adverse effects were mild. Conclusion PSR combined with radiation therapy is an effective and safe strategy to treat keloids. Location could be a factor that affects curative effects.
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Affiliation(s)
- Wenyun Ting
- Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Yuming Chong
- Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China.,Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Jing Xu
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Jiuzuo Huang
- Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Nanze Yu
- Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Zhifei Liu
- Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
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Pal R, Edward K, Ma L, Qiu S, Vargas G. Spectroscopic characterization of oral epithelial dysplasia and squamous cell carcinoma using multiphoton autofluorescence micro-spectroscopy. Lasers Surg Med 2017; 49:866-873. [PMID: 28677822 DOI: 10.1002/lsm.22697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2017] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Multiphoton autofluorescence microscopy (MPAM) has shown potential in identifying features that are directly related to tissue microstructural and biochemical changes throughout epithelial neoplasia. In this study, we evaluate the autofluorescence spectral characteristics of neoplastic epithelium in dysplasia and oral squamous cell carcinoma (OSCC) using multiphoton autofluorescence spectroscopy (MPAS) in an in vivo hamster model of oral neoplasia in order to identify unique signatures that could be used to delineate normal oral mucosa from neoplasia. MATERIALS/METHODS A 9,10-dimethyl-1,2-benzanthracene (DMBA) hamster model of oral precancer and OSCC was used for in vivo MPAM and MPAS. Multiphoton Imaging and spectroscopy were performed with 780 nm excitation while a bandpass emission 450-650 nm was used for MPAM. Autofluorescence spectra was collected in the spectral window of 400-650 nm. RESULTS MPAS with fluorescence excitation at 780 nm revealed an overall red shift of a primary blue-green peak (480-520 nm) that is attributed to NADH and FAD. In the case of oral squamous cell carcinoma (OSCC) and some high-grade dysplasia an additional prominent peak at 635 nm, attributed to PpIX was observed. The fluorescence intensity at 635 nm and an intensity ratio of the primary blue-green peak versus 635 nm peak, showed statistically significant difference between control and neoplastic tissue. DISCUSSION Neoplastic transformation in the epithelium is known to alter the intracellular homeostasis of important tissue metabolites such as NADH, FAD, and PpIX, which was observed by MPAS in their native environment. A combination of deep tissue microscopy owing to higher penetration depth of multiphoton excitation and depth resolved spectroscopy could prove to be invaluable in identification of cytologic as well as biomolecular spectral characteristic of oral epithelial neoplasia. Lasers Surg. Med. 49:866-873, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Rahul Pal
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, Texas, 77555.,Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, 77555
| | - Kert Edward
- Department of Physics, University of the West Indies, UWI Mona, Kingston 7, Mona, Jamaica
| | - Liang Ma
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, Texas, 77555
| | - Suimin Qiu
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, 77555
| | - Gracie Vargas
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, Texas, 77555.,Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, Texas, 77555
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Watté R, Aernouts B, Van Beers R, Postelmans A, Saeys W. Computational optimization of the configuration of a spatially resolved spectroscopy sensor for milk analysis. Anal Chim Acta 2016; 917:53-63. [PMID: 27026600 DOI: 10.1016/j.aca.2016.02.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/23/2016] [Accepted: 02/28/2016] [Indexed: 11/17/2022]
Abstract
A global optimizer has been developed, capable of computing the optimal configuration in a probe for spatially resolved reflectance spectroscopy (SRS). The main objective is to minimize the number of detection fibers, while maintaining an accurate estimation of both absorption and scattering profiles. Multiple fibers are necessary to robustify the estimation of optical properties against noise, which is typically present in the measured signals and influences the accuracy of the inverse estimation. The optimizer is based on a robust metamodel-based inverse estimation of the absorption coefficient and a reduced scattering coefficient from the acquired SRS signals. A genetic algorithm is used to evaluate the effect of the fiber placement on the performance of the inverse estimator to find the bulk optical properties of raw milk. The algorithm to find the optimal fiber placement was repeatedly executed for cases with a different number of detection fibers, ranging from 3 to 30. Afterwards, the optimal designs for each considered number of fibers were compared based on their performance in separating the absorption and scattering properties, and the significance of the differences was tested. A sensor configuration with 13 detection fibers was found to be the combination with the lowest number of fibers which provided an estimation performance which was not significantly worse than the one obtained with the best design (30 detection fibers). This design resulted in the root mean squared error of prediction (RMSEP) of 1.411 cm(-1) (R(2) = 0.965) for the estimation of the bulk absorption coefficient values, and 0.382 cm(-1) (R(2) = 0.996) for the reduced scattering coefficient values.
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Affiliation(s)
- Rodrigo Watté
- KU Leuven Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
| | - Ben Aernouts
- KU Leuven Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
| | - Robbe Van Beers
- KU Leuven Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
| | - Annelies Postelmans
- KU Leuven Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
| | - Wouter Saeys
- KU Leuven Department of Biosystems, MeBioS, Kasteelpark Arenberg 30, 3001 Leuven, Belgium.
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Ebenezar J, Aruna PR, Ganesan S. Native fluorescence spectroscopic characterization of DMBA induced carcinogenesis in mice skin for the early detection of tissue transformation. Analyst 2015; 140:4170-81. [DOI: 10.1039/c4an00650j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The objective of the study is to characterize the endogenous porphyrin fluorescence in a dimethylbenz(a)anthracene (DMBA) induced mouse skin tumor model using native fluorescence emission and excitation spectroscopy.
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Gamm UA, Hoy CL, van Leeuwen - van Zaane F, Sterenborg HJCM, Kanick SC, Robinson DJ, Amelink A. Extraction of intrinsic fluorescence from single fiber fluorescence measurements on a turbid medium: experimental validation. BIOMEDICAL OPTICS EXPRESS 2014; 5:1913-25. [PMID: 24940549 PMCID: PMC4052919 DOI: 10.1364/boe.5.001913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/09/2014] [Accepted: 02/10/2014] [Indexed: 05/21/2023]
Abstract
The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is demonstrated using a set of fluorescent phantoms with varying concentrations of Intralipid to vary the scattering properties, yielding a wide range of reduced scattering coefficients (μ's = 0-7 mm (-1)). We also introduce a small modification to the model to account for the case of μ's = 0 mm (-1) and show its relation to the experimental, simulated and theoretically calculated value of SFF intensity in the absence of scattering. Finally, we show that our method is also accurate in the presence of absorbers by performing measurements on phantoms containing red blood cells and correcting for their absorption properties.
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Affiliation(s)
- U. A. Gamm
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
| | - C. L. Hoy
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
| | - F. van Leeuwen - van Zaane
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
| | - H. J. C. M. Sterenborg
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
| | - S. C. Kanick
- Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, New Hampshire 03755,
USA
| | - D. J. Robinson
- Department of Otorhinolaryngology-Head and Neck Surgery, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
| | - A. Amelink
- Center for Optical Diagnostics and Therapy, Department of Radiation Oncology, Postgraduate school Molecular Medicine, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam,
The Netherlands
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Pery E, Blondel WCPM, Tindel S, Ghribi M, Leroux A, Guillemin F. Spectral Features Selection and Classification for Bimodal Optical Spectroscopy Applied to Bladder Cancer In Vivo Diagnosis. IEEE Trans Biomed Eng 2014; 61:207-16. [DOI: 10.1109/tbme.2010.2103559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gomes AJ, Backman V. Analytical light reflectance models for overlapping illumination and collection area geometries. APPLIED OPTICS 2012. [PMID: 23207312 PMCID: PMC3655705 DOI: 10.1364/ao.51.008013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Several biomedical applications, such as detection of dysplasia, require selective interrogation of superficial tissue structures less than a few hundred micrometers thick. Techniques and methods have been developed to limit the penetration depth of light in tissue, including the design of systems such as fiber-optic probes that have overlapping illumination and collection areas on the tissue surface. For such geometries, the diffusion approximation to the light-transport equation typically does not apply, and as a result there is no general model to extract tissue optical properties from reflectance measurements. In the current study, we employ Monte Carlo (MC) simulations to develop simple and compact analytical models for the light reflectance from these overlapping geometries. These models incorporate the size of the illumination and collection areas, the collection angle, the polarization of the incident light, and the optical properties of the sample. Moreover, these MC simulations use the Whittle-Matérn model to describe scattering from spatially continuous refractive index media such as tissue, which is more general than models based on the conventionally used Henyey-Greenstein model. We validated these models on tissue-simulating phantoms. The models developed herein will facilitate the extraction of optical properties and aid in the design of optical systems employing overlapping illumination and collection areas, including fiber-optic probes for in vivo tissue diagnosis.
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Adur J, Pelegati VB, de Thomaz AA, Baratti MO, Almeida DB, Andrade LALA, Bottcher-Luiz F, Carvalho HF, Cesar CL. Optical biomarkers of serous and mucinous human ovarian tumor assessed with nonlinear optics microscopies. PLoS One 2012; 7:e47007. [PMID: 23056557 PMCID: PMC3466244 DOI: 10.1371/journal.pone.0047007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 09/11/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Nonlinear optical (NLO) microscopy techniques have potential to improve the early detection of epithelial ovarian cancer. In this study we showed that multimodal NLO microscopies, including two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG), third-harmonic generation (THG) and fluorescence lifetime imaging microscopy (FLIM) can detect morphological and metabolic changes associated with ovarian cancer progression. METHODOLOGY/PRINCIPAL FINDINGS We obtained strong TPEF + SHG + THG signals from fixed samples stained with Hematoxylin & Eosin (H&E) and robust FLIM signal from fixed unstained samples. Particularly, we imaged 34 ovarian biopsies from different patients (median age, 49 years) including 5 normal ovarian tissue, 18 serous tumors and 11 mucinous tumors with the multimodal NLO platform developed in our laboratory. We have been able to distinguish adenomas, borderline, and adenocarcinomas specimens. Using a complete set of scoring methods we found significant differences in the content, distribution and organization of collagen fibrils in the stroma as well as in the morphology and fluorescence lifetime from epithelial ovarian cells. CONCLUSIONS/SIGNIFICANCE NLO microscopes provide complementary information about tissue microstructure, showing distinctive patterns for serous and mucinous ovarian tumors. The results provide a basis to interpret future NLO images of ovarian tissue and lay the foundation for future in vivo optical evaluation of premature ovarian lesions.
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MESH Headings
- Adenocarcinoma, Mucinous/diagnosis
- Adenocarcinoma, Mucinous/metabolism
- Adenocarcinoma, Mucinous/pathology
- Biomarkers, Tumor/metabolism
- Carcinoma, Ovarian Epithelial
- Female
- Humans
- Microscopy
- Microscopy, Fluorescence, Multiphoton
- Middle Aged
- Neoplasms, Glandular and Epithelial/diagnosis
- Neoplasms, Glandular and Epithelial/metabolism
- Neoplasms, Glandular and Epithelial/pathology
- Ovarian Neoplasms/diagnosis
- Ovarian Neoplasms/metabolism
- Ovarian Neoplasms/pathology
- Ovary/metabolism
- Ovary/pathology
- Serum/metabolism
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Affiliation(s)
- Javier Adur
- Biophotonic Group, Optics and Photonics Research Center (CEPOF), Institute of Physics Gleb Wataghin, State University of Campinas - UNICAMP, Campinas, São Paulo, Brazil.
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9
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Gomes AJ, Turzhitsky V, Ruderman S, Backman V. Monte Carlo model of the penetration depth for polarization gating spectroscopy: influence of illumination-collection geometry and sample optical properties. APPLIED OPTICS 2012; 51:4627-37. [PMID: 22781238 PMCID: PMC3557942 DOI: 10.1364/ao.51.004627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Polarization-gating has been widely used to probe superficial tissue structures, but the penetration depth properties of this method have not been completely elucidated. This study employs a polarization-sensitive Monte Carlo method to characterize the penetration depth statistics of polarization-gating. The analysis demonstrates that the penetration depth depends on both the illumination-collection geometry [illumination-collection area (R) and collection angle (θ(c))] and on the optical properties of the sample, which include the scattering coefficient (μ(s)), absorption coefficient (μ(a)), anisotropy factor (g), and the type of the phase function. We develop a mathematical expression relating the average penetration depth to the illumination-collection beam properties and optical properties of the medium. Finally, we quantify the sensitivity of the average penetration depth to changes in optical properties for different geometries of illumination and collection. The penetration depth model derived in this study can be applied to optimizing application-specific fiber-optic probes to target a sampling depth of interest with minimal sensitivity to the optical properties of the sample.
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Affiliation(s)
- Andrew J. Gomes
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60218, USA
| | - Vladimir Turzhitsky
- Biomedical Imaging and Spectroscopy Laboratory, Departments of Medicine and Obstetrics and Gynecology and Reproductive Biology, Beth Israel Deaconess Medical Center, Harvard University, Boston, Massachusetts 02215, USA
| | - Sarah Ruderman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60218, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60218, USA
- Corresponding author:
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10
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Edward K, Qiu S, Resto V, McCammon S, Vargas G. In vivo layer-resolved characterization of oral dysplasia via nonlinear optical micro-spectroscopy. BIOMEDICAL OPTICS EXPRESS 2012; 3:1579-93. [PMID: 22808430 PMCID: PMC3395483 DOI: 10.1364/boe.3.001579] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 05/13/2023]
Abstract
Optical spectroscopy has proven to be a powerful technique for studying neoplastic transformation in epithelial tissue. Since specific intra-layer precancerous changes originate in the stratified layers of the oral mucosa, layer-resolved analysis will likely improve both our understanding of the mechanism of premalignant transformation, and clinical diagnostic outcomes. However, the native fluorescence signal in linear spectroscopy typically originates from a multi-layered focal volume. In this study, nonlinear spectroscopy was exploited for in vivo layer-resolved discrimination between normal and dysplastic tissue for the first time. Our results revealed numerous intra-layer specific differences.
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Affiliation(s)
- Kert Edward
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Suimin Qiu
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Cancers of the Head and Neck, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Vicente Resto
- Department of Otolaryngology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Cancers of the Head and Neck, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Susan McCammon
- Department of Otolaryngology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Cancers of the Head and Neck, The University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Gracie Vargas
- Center for Biomedical Engineering, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Center for Cancers of the Head and Neck, The University of Texas Medical Branch, Galveston, TX 77555, USA
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11
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Pfefer TJ, Wang Q, Drezek RA. Monte Carlo modeling of time-resolved fluorescence for depth-selective interrogation of layered tissue. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2011; 104:161-7. [PMID: 21111507 DOI: 10.1016/j.cmpb.2010.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 09/23/2010] [Accepted: 10/17/2010] [Indexed: 05/05/2023]
Abstract
Computational approaches for simulation of light-tissue interactions have provided extensive insight into biophotonic procedures for diagnosis and therapy. However, few studies have addressed simulation of time-resolved fluorescence (TRF) in tissue and none have combined Monte Carlo simulations with standard TRF processing algorithms to elucidate approaches for cancer detection in layered biological tissue. In this study, we investigate how illumination-collection parameters (e.g., collection angle and source-detector separation) influence the ability to measure fluorophore lifetime and tissue layer thickness. Decay curves are simulated with a Monte Carlo TRF light propagation model. Multi-exponential iterative deconvolution is used to determine lifetimes and fractional signal contributions. The ability to detect changes in mucosal thickness is optimized by probes that selectively interrogate regions superficial to the mucosal-submucosal boundary. Optimal accuracy in simultaneous determination of lifetimes in both layers is achieved when each layer contributes 40-60% of the signal. These results indicate that depth-selective approaches to TRF have the potential to enhance disease detection in layered biological tissue and that modeling can play an important role in probe design optimization.
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Affiliation(s)
- T Joshua Pfefer
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD 20993, United States.
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Vishwanath K, Chang K, Klein D, Deng YF, Chang V, Phelps JE, Ramanujam N. Portable, Fiber-Based, Diffuse Reflection Spectroscopy (DRS) Systems for Estimating Tissue Optical Properties. APPLIED SPECTROSCOPY 2011; 62:206-215. [PMID: 21499501 PMCID: PMC3074566 DOI: 10.1366/10-06052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Steady-state diffuse reflection spectroscopy is a well-studied optical technique that can provide a noninvasive and quantitative method for characterizing the absorption and scattering properties of biological tissues. Here, we compare three fiber-based diffuse reflection spectroscopy systems that were assembled to create a light-weight, portable, and robust optical spectrometer that could be easily translated for repeated and reliable use in mobile settings. The three systems were built using a broadband light source and a compact, commercially available spectrograph. We tested two different light sources and two spectrographs (manufactured by two different vendors). The assembled systems were characterized by their signal-to-noise ratios, the source-intensity drifts, and detector linearity. We quantified the performance of these instruments in extracting optical properties from diffuse reflectance spectra in tissue-mimicking liquid phantoms with well-controlled optical absorption and scattering coefficients. We show that all assembled systems were able to extract the optical absorption and scattering properties with errors less than 10%, while providing greater than ten-fold decrease in footprint and cost (relative to a previously well-characterized and widely used commercial system). Finally, we demonstrate the use of these small systems to measure optical biomarkers in vivo in a small-animal model cancer therapy study. We show that optical measurements from the simple portable system provide estimates of tumor oxygen saturation similar to those detected using the commercial system in murine tumor models of head and neck cancer.
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Turzhitsky V, Radosevich A, Rogers JD, Taflove A, Backman V. A predictive model of backscattering at subdiffusion length scales. BIOMEDICAL OPTICS EXPRESS 2010; 1:1034-1046. [PMID: 21258528 PMCID: PMC3018048 DOI: 10.1364/boe.1.001034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/27/2010] [Accepted: 09/26/2010] [Indexed: 05/04/2023]
Abstract
We provide a methodology for accurately predicting elastic backscattering radial distributions from random media with two simple empirical models. We apply these models to predict the backscattering based on two classes of scattering phase functions: the Henyey-Greenstein phase function and a generalized two parameter phase function that is derived from the Whittle-Matérn correlation function. We demonstrate that the model has excellent agreement over all length scales and has less than 1% error for backscattering at subdiffusion length scales for tissue-relevant optical properties. The presented model is the first available approach for accurately predicting backscattering at length scales significantly smaller than the transport mean free path.
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Affiliation(s)
- Vladimir Turzhitsky
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Andrew Radosevich
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Jeremy D. Rogers
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Allen Taflove
- Department of Electrical Engineering and Computer, Northwestern University, Evanston, IL 60208, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
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Sivabalan S, Vedeswari CP, Jayachandran S, Koteeswaran D, Pravda C, Aruna PR, Ganesan S. In vivo native fluorescence spectroscopy and nicotinamide adinine dinucleotide/flavin adenine dinucleotide reduction and oxidation states of oral submucous fibrosis for chemopreventive drug monitoring. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:017010. [PMID: 20210484 DOI: 10.1117/1.3324771] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Native fluorescence spectroscopy has shown potential to characterize and diagnose oral malignancy. We aim at extending the native fluorescence spectroscopy technique to characterize normal and oral submucous fibrosis (OSF) patients under pre- and post-treated conditions, and verify whether this method could also be considered in the monitoring of therapeutic prognosis noninvasively. In this study, 28 normal subjects and 28 clinically proven cases of OSF in the age group of 20 to 40 years are diagnosed using native fluorescence spectroscopy. The OSF patients are given dexamethasone sodium phosphate and hyaluronidase twice a week for 6 weeks, and the therapeutic response is monitored using fluorescence spectroscopy. The fluorescence emission spectra of normal and OSF cases of both pre- and post-treated conditions are recorded in the wavelength region of 350 to 600 nm at an excitation wavelength of 330 nm. The statistical significance is verified using discriminant analysis. The oxidation-reduction ratio of the tissue is also calculated using the fluorescence emission intensities of flavin adenine dinucleotide and nicotinamide adinine dinucleotide at 530 and 440 nm, respectively, and they are compared with conventional physical clinical examinations. This study suggests that native fluorescence spectroscopy could also be extended to OSF diagnosis and therapeutic prognosis.
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Affiliation(s)
- Shanmugam Sivabalan
- Anna University Chennai, Department of Physics, Division of Medical Physics and Lasers, Chennai, India
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Thilwind RE, 't Hooft G, Uzunbajakava NE. Improved depth resolution in near-infrared diffuse reflectance spectroscopy using obliquely oriented fibers. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:024026. [PMID: 19405755 DOI: 10.1117/1.3103339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We demonstrate a significant improvement of depth selectivity when using obliquely oriented fibers for near-infrared (NIR) diffuse reflectance spectroscopy. This is confirmed by diffuse reflectance measurements of a two-layer tissue-mimicking phantom across the spectral range from 1,000 to 1,940 nm. The experimental proof is supported by Monte Carlo simulations. The results reveal up to fourfold reduction in the mean optical penetration depth, twofold reduction in its variation, and a decrease in the number of scattering events when a single fiber is oriented at an angle of 60 deg. The effect of reducing the mean optical penetration depth is enhanced by orienting both fibers inwardly. Using outwardly oriented fibers enables more selective probing of deeper layers, while reducing the contribution from surface layers. We further demonstrate that the effect of an inward oblique arrangement can be approximated to a decrease in fiber-to-fiber separation in the case of a perpendicular fiber arrangement. This approximation is valid in the weak- or absorption-free regime. Our results assert the advantages of using obliquely oriented fibers when attempting to specifically address superficial tissue layers, for example, for skin cancer detection, or in noninvasive glucose monitoring. Such flexibility could be further advantageous in a range of minimally invasive applications, including catheter-based interventions.
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Hillman EMC, Burgess SA. Sub-millimeter resolution 3D optical imaging of living tissue using laminar optical tomography. LASER & PHOTONICS REVIEWS 2009; 3:159-179. [PMID: 19844595 PMCID: PMC2763333 DOI: 10.1002/lpor.200810031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In-vivo imaging of optical contrast in living tissues can allow measurement of functional parameters such as blood oxygenation and detection of targeted and active fluorescent contrast agents. However, optical imaging must overcome the effects of light scattering, which limit the penetration depth and can affect quantitation and sensitivity. This article focuses on a technique for high-resolution, high-speed depth-resolved optical imaging of superficial living tissues called laminar optical tomography (LOT), which is capable of imaging absorbing and fluorescent contrast in living tissues to depths of 2-3 mm with 100-200 micron resolution. An overview of the advantages and challenges of in-vivo optical imaging is followed by a review of currently available techniques for high-resolution optical imaging of tissues. LOT is then described, including a description of the imaging system design and discussion of data analysis and image reconstruction approaches. Examples of recent applications of LOT are then provided and compared to other existing technologies.By measuring multiply-scattered light, Laminar Optical Tomography can probe beneath the surface of living tissues such as the skin and brain.
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Turzhitsky VM, Gomes AJ, Kim YL, Liu Y, Kromine A, Rogers JD, Jameel M, Roy HK, Backman V. Measuring mucosal blood supply in vivo with a polarization-gating probe. APPLIED OPTICS 2008; 47:6046-57. [PMID: 19002229 PMCID: PMC2728617 DOI: 10.1364/ao.47.006046] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
There has been significant interest in developing depth-selective optical interrogation of biological tissue in general and of superficial (e.g., mucosal) tissue in particular. We report an in vivo polarization-gating fiber-optic probe that obtains backscattering spectroscopic measurements from a range of near-surface depths (100-200 microm). The design and testing was performed with polarized light Monte Carlo simulations and in tissue model experiments. We used the probe to investigate mucosal changes in early carcinogenesis. Measurements performed in the colonic mucosa of 125 human subjects provide the first in vivo evidence that mucosal blood supply is increased early in carcinogenesis, not only in precancerous adenomatous lesions, but also in the histologically normal-appearing tissue surrounding these lesions. This effect was primarily limited to the mucosal microcirculation and was not present in the larger blood vessels located deeper in colonic tissue.
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Affiliation(s)
- Vladimir M Turzhitsky
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60201, USA.
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Kortun C, Hijazi YR, Arifler D. Combined Monte Carlo and finite-difference time-domain modeling for biophotonic analysis: implications on reflectance-based diagnosis of epithelial precancer. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:034014. [PMID: 18601559 DOI: 10.1117/1.2939405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Monte Carlo (MC) modeling of photon transport in tissues is generally performed using simplified functions that only approximate the angular scattering properties of tissue constituents. However, such approximations may not be sufficient for fully characterizing tissue scatterers such as cells. Finite-difference time-domain (FDTD) modeling provides a flexible approach to compute realistic tissue phase functions that describe probability of scattering at different angles. We describe a computational framework that combines MC and FDTD modeling, and allows random sampling of scattering directions from FDTD phase functions. We carry out simulations to assess the influence of incorporating realistic FDTD phase functions on modeling spectroscopic reflectance signals obtained from normal and precancerous epithelial tissues. Simulations employ various fiber optic probe designs to analyze the sensitivity of different probe geometries to FDTD-generated phase functions. Combined MC/FDTD modeling results indicate that the form of the phase function used is an important factor in determining the reflectance profile of tissues, and detected reflectance intensity can change up to approximately 30% when a realistic FDTD phase function is used instead of an approximating function. The results presented need to be taken into account when developing photon propagation models or implementing inverse algorithms to extract optical properties from measurements.
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Affiliation(s)
- Cemre Kortun
- University College London, Department of Medical Physics and Bioengineering, London WC1E 6BT, United Kingdom
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Schwarz RA, Gao W, Daye D, Williams MD, Richards-Kortum R, Gillenwater AM. Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe. APPLIED OPTICS 2008; 47:825-34. [PMID: 18288232 PMCID: PMC2773166 DOI: 10.1364/ao.47.000825] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Optical spectroscopy can provide useful diagnostic information about the morphological and biochemical changes related to the progression of precancer in epithelial tissue. As precancerous lesions develop, the optical properties of both the superficial epithelium and underlying stroma are altered; measuring spectral data as a function of depth has the potential to improve diagnostic performance. We describe a clinical spectroscopy system with a depth-sensitive, ball lens coupled fiber-optic probe for noninvasive in vivo measurement of oral autofluorescence and diffuse reflectance spectra. We report results of spectroscopic measurements from oral sites in normal volunteers and in patients with neoplastic lesions of the oral mucosa; results indicate that the addition of depth selectivity can enhance the detection of optical changes associated with precancer.
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Affiliation(s)
- Richard A Schwarz
- Department of Bioengineering MS 142, Rice University, 6100 Main Street, Keck Hall Suite 116, Houston, Texas 77005, USA.
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Jaillon F, Zheng W, Huang Z. Beveled fiber-optic probe couples a ball lens for improving depth-resolved fluorescence measurements of layered tissue: Monte Carlo simulations. Phys Med Biol 2008; 53:937-51. [DOI: 10.1088/0031-9155/53/4/008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Combined Endoscopic Optical Coherence Tomography and Laser Induced Fluorescence. OPTICAL COHERENCE TOMOGRAPHY 2008. [DOI: 10.1007/978-3-540-77550-8_26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia. Proc Natl Acad Sci U S A 2007; 104:19494-9. [PMID: 18042710 DOI: 10.1073/pnas.0708425104] [Citation(s) in RCA: 636] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Metabolic imaging of the relative amounts of reduced NADH and FAD and the microenvironment of these metabolic electron carriers can be used to noninvasively monitor changes in metabolism, which is one of the hallmarks of carcinogenesis. This study combines cellular redox ratio, NADH and FAD lifetime, and subcellular morphology imaging in three dimensions to identify intrinsic sources of metabolic and structural contrast in vivo at the earliest stages of cancer development. There was a significant (P < 0.05) increase in the nuclear to cytoplasmic ratio (NCR) with depth within the epithelium in normal tissues; however, there was no significant change in NCR with depth in precancerous tissues. The redox ratio significantly decreased in the less differentiated basal epithelial cells compared with the more mature cells in the superficial layer of the normal stratified squamous epithelium, indicating an increase in metabolic activity in cells with increased NCR. However, the redox ratio was not significantly different between the superficial and basal cells in precancerous tissues. A significant decrease was observed in the contribution and lifetime of protein-bound NADH (averaged over the entire epithelium) in both low- and high-grade epithelial precancers compared with normal epithelial tissues. In addition, a significant increase in the protein-bound FAD lifetime and a decrease in the contribution of protein-bound FAD are observed in high-grade precancers only. Increased intracellular variability in the redox ratio, NADH, and FAD fluorescence lifetimes were observed in precancerous cells compared with normal cells.
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Wang A, Nammalavar V, Drezek R. Targeting spectral signatures of progressively dysplastic stratified epithelia using angularly variable fiber geometry in reflectance Monte Carlo simulations. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:044012. [PMID: 17867816 DOI: 10.1117/1.2769328] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A key component of accurate spectroscopic-based cancer diagnostics is the ability to differentiate spectral variations resulting from epithelial tissue dysplasia. Such measurement may be enhanced by discretely probing the optical properties of the epithelial tissue where the morphological and biochemical features vary according to tissue depths. More precisely, layer-specific changes in tissue optical properties correlated to cellular dysplasia can be determined by conventional reflectance spectroscopy when it is coupled with angularly variable fiber geometry. Thus, this study addresses how angularly variable fiber geometry can resolve spatially specific spectral signatures of tissue pathology by interpreting and analyzing the reflectance spectra of increasingly dysplastic epithelial tissue in reflectance-mode Monte Carlo simulation. Specifically, by increasing the obliquity of the collection fibers from 0 to 40 deg in the direction facing toward the illumination fiber, the spectral sensitivity to tissue abnormalities in the epithelial layer is thereby improved, whereas orthogonal fibers are more sensitive to the changes in the stromal layer.
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Affiliation(s)
- Adrien Wang
- Rice University, Department of Bioengineering, Houston, Texas 77251-1892, USA
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Wang A, Nammalavar V, Drezek R. Experimental evaluation of angularly variable fiber geometry for targeting depth-resolved reflectance from layered epithelial tissue phantoms. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:044011. [PMID: 17867815 DOI: 10.1117/1.2769331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The present study focuses on enhancing the sensitivity and specificity of spectral diagnosis in a stratified architecture that models human cervical epithelia by experimentally demonstrating the efficacy of using angularly variable fiber geometry to achieve the desired layer selection and probing depths. The morphological and biochemical features of epithelial tissue vary in accordance with tissue depths; consequently, the accuracy of spectroscopic diagnosis of epithelial dysplasia may be enhanced by probing the optical properties of this tissue. In the case of cellular dysplasia, layer-specific changes in tissue optical properties may be optimally determined by reflectance spectroscopy when specifically coupled with angularly variable fiber geometry. This study addresses the utility of using such angularly variable fiber geometry for resolving spatially specific spectra of a two-layer epithelial tissue phantom. Spectral sensitivity to the scattering particles embedded in the epithelial phantom layer is shown to significantly improve as the obliquity of the collection fibers increases from 0 to 40 deg. Conversely, the orthogonal fibers are found to be more sensitive to changes in the stromal phantom layer.
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Affiliation(s)
- Adrien Wang
- Rice University, Department of Bioengineering, Houston, Texas 77251-1892, USA
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Skala MC, Palmer GM, Vrotsos KM, Gendron-Fitzpatrick A, Ramanujam N. Comparison of a physical model and principal component analysis for the diagnosis of epithelial neoplasias in vivo using diffuse reflectance spectroscopy. OPTICS EXPRESS 2007; 15:7863-75. [PMID: 17912337 PMCID: PMC1999391 DOI: 10.1364/oe.15.007863] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We explored the use of diffuse reflectance spectroscopy in the ultraviolet-visible (UV-VIS) spectrum for the diagnosis of epithelial precancers and cancers in vivo. A physical model (Monte Carlo inverse model) and an empirical model (principal component analysis, (PCA)) based approach were compared for extracting diagnostic features from diffuse reflectance spectra measured in vivo from the dimethylbenz[alpha]anthracene-treated hamster cheek pouch model of oral carcinogenesis. These diagnostic features were input into a support vector machine algorithm to classify each tissue sample as normal (n=10) or neoplastic (dysplasia to carcinoma, n=10) and cross-validated using a leave one out method. There was a statistically significant decrease in the absorption and reduced scattering coefficient at 460 nm in neoplastic compared to normal tissues, and these two features provided 90% classification accuracy. The first two principal components extracted from PCA provided a classification accuracy of 95%. The first principal component was highly correlated with the wavelength-averaged reduced scattering coefficient. Although both methods show similar classification accuracy, the physical model provides insight into the physiological and structural features that discriminate between normal and neoplastic tissues and does not require a priori, a representative set of spectral data from which to derive the principal components.
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Affiliation(s)
- Melissa C Skala
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
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Millon SR, Roldan-Perez KM, Riching KM, Palmer GM, Ramanujam N. Effect of optical clearing agents on the in vivo optical properties of squamous epithelial tissue. Lasers Surg Med 2007; 38:920-7. [PMID: 17163473 DOI: 10.1002/lsm.20451] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVES Optical clearing agents (OCAs) have previously been shown to increase depth penetration within turbid tissue ex vivo. This paper quantifies tissue optical properties of the hamster cheek pouch model in order to provide a means to assess the effect of OCAs quantitatively in vivo. STUDY DESIGN/MATERIALS AND METHODS Diffuse reflectance spectra were obtained from both cheeks of 12 hamsters before and after immersion in dimethyl sulfoxide (DMSO), glycerol or a phosphate buffer saline (PBS) control for 20 minutes. A Monte Carlo model was then utilized to derive the wavelength dependent reduced scattering and absorption coefficients. RESULTS DMSO caused a statistically significant decrease in the absorption and reduced scattering coefficients derived by the model. Glycerol caused a statistically significant increase in the wavelength dependent absorption coefficient, but no statistically significant changes in the reduced scattering coefficient. CONCLUSIONS DMSO and glycerol act upon tissues differently as reflected by the tissue optical properties, implying that not all OCAs are equally effective in optically clearing tissues.
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Affiliation(s)
- Stacy R Millon
- Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA
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27
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Skala MC, Riching KM, Bird DK, Gendron-Fitzpatrick A, Eickhoff J, Eliceiri KW, Keely PJ, Ramanujam N. In vivo multiphoton fluorescence lifetime imaging of protein-bound and free nicotinamide adenine dinucleotide in normal and precancerous epithelia. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:024014. [PMID: 17477729 PMCID: PMC2743958 DOI: 10.1117/1.2717503] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Multiphoton fluorescence lifetime imaging microscopy (FLIM) is a noninvasive, cellular resolution, 3-D functional imaging technique. We investigate the potential for in vivo precancer diagnosis with metabolic imaging via multiphoton FLIM of the endogenous metabolic cofactor nicotinamide adenine dinucleotide (NADH). The dimethylbenz[alpha]anthracene (DMBA)-treated hamster cheek pouch model of oral carcinogenesis and MCF10A cell monolayers are imaged using multiphoton FLIM at 780-nm excitation. The cytoplasm of normal hamster cheek pouch epithelial cells has short (0.29+/-0.03 ns) and long lifetime components (2.03+/-0.06 ns), attributed to free and protein-bound NADH, respectively. Low-grade precancers (mild to moderate dysplasia) and high-grade precancers (severe dysplasia and carcinoma in situ) are discriminated from normal tissues by their decreased protein-bound NADH lifetime (p<0.05). Inhibition of cellular glycolysis and oxidative phosphorylation in cell monolayers produces an increase and decrease, respectively, in the protein-bound NADH lifetime (p<0.05). Results indicate that the decrease in protein-bound NADH lifetime with dysplasia is due to a shift from oxidative phosphorylation to glycolysis, consistent with the predictions of neoplastic metabolism. We demonstrate that multiphoton FLIM is a powerful tool for the noninvasive characterization and detection of epithelial precancers in vivo.
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Affiliation(s)
- Melissa C. Skala
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Kristin M. Riching
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706
| | - Damian K. Bird
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI 53706
| | | | - Jens Eickhoff
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI 53706
| | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI 53706
| | - Patricia J. Keely
- Department of Pharmacology, University of Wisconsin, Madison, WI 53706
| | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
- For Correspondence: Nirmala Ramanujam, Dept. Biomedical Engineering, Duke University, Rm. 2575 CIEMAS, Durham, NC 27708-0281, Phone: 660-5307, Fax:(919) 684-4488,
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Arifler D, Pavlova I, Gillenwater A, Richards-Kortum R. Light scattering from collagen fiber networks: micro-optical properties of normal and neoplastic stroma. Biophys J 2007; 92:3260-74. [PMID: 17307834 PMCID: PMC1852360 DOI: 10.1529/biophysj.106.089839] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development of epithelial precancer and cancer leads to well-documented molecular and structural changes in the epithelium. Recently, it has been recognized that stromal biology is also altered significantly with preinvasive disease. We used the finite-difference time-domain method, a popular technique in computational electromagnetics, to model light scattering from heterogeneous collagen fiber networks and to analyze how neoplastic changes alter stromal scattering properties. Three-dimensional optical images from the stroma of fresh normal and neoplastic oral-cavity biopsies were acquired using fluorescence confocal microscopy. These optical sections were then processed to create realistic three-dimensional collagen networks as model input. Image analysis revealed that the volume fraction of collagen fibers in the stroma decreases with precancer and cancer progression, and fibers tend to be shorter and more disconnected in neoplastic stroma. The finite-difference time-domain modeling results showed that neoplastic fiber networks have smaller scattering cross sections compared to normal networks. Computed scattering-phase functions indicate that high-angle scattering probabilities tend to be higher for neoplastic networks. These results provide valuable insight into the micro-optical properties of normal and neoplastic stroma. Characterization of optical signals obtained from epithelial tissues can aid in development of optical spectroscopic and imaging techniques for noninvasive monitoring of early neoplastic changes.
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Affiliation(s)
- Dizem Arifler
- Department of Physics, Eastern Mediterranean University, Famagusta, Cyprus
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Seo I, You JS, Hayakawa CK, Venugopalan V. Perturbation and differential Monte Carlo methods for measurement of optical properties in a layered epithelial tissue model. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:014030. [PMID: 17343505 DOI: 10.1117/1.2697735] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The use of perturbation and differential Monte Carlo (pMC/dMC) methods in conjunction with nonlinear optimization algorithms were proposed recently as a means to solve inverse photon migration problems in regionwise heterogeneous turbid media. We demonstrate the application of pMC/dMC methods for the recovery of optical properties in a two-layer extended epithelial tissue model from experimental measurements of spatially resolved diffuse reflectance. The results demonstrate that pMC/dMC methods provide a rapid and accurate approach to solve two-region inverse photon migration problems in the transport regime, that is, on spatial scales smaller than a transport mean free path and in media where optical scattering need not dominate absorption. The pMC/dMC approach is found to be effective over a broad range of absorption (50 to 400%) and scattering (70 to 130%) perturbations. The recovery of optical properties from spatially resolved diffuse reflectance measurements is examined for different sets of source-detector separation. These results provide some guidance for the design of compact fiber-based probes to determine and isolate optical properties from both epithelial and stromal layers of superficial tissues.
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Affiliation(s)
- InSeok Seo
- University of California, Irvine, Department of Chemical Engineering and Materials Science, Irvine, California 92697, USA
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Arifler D, MacAulay C, Follen M, Richards-Kortum R. Spatially resolved reflectance spectroscopy for diagnosis of cervical precancer: Monte Carlo modeling and comparison to clinical measurements. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:064027. [PMID: 17212550 DOI: 10.1117/1.2398932] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present Monte Carlo modeling studies to provide a quantitative understanding of contrast observed in spatially resolved reflectance spectra of normal and highly dysplastic cervical tissue. Simulations have been carried out to analyze the sensitivity of spectral measurements to a range of changes in epithelial and stromal optical properties that are reported to occur as dysplasia develops and to predict reflectance spectra of normal and highly dysplastic tissue at six different source-detector separations. Simulation results provide important insights into specific contributions of different optical parameters to the overall spectral response. Predictions from simulations agree well with in vivo measurements from cervical tissue and successfully describe spectral differences observed in reflectance measurements from normal and precancerous tissue sites. Penetration depth statistics of photons detected at the six source-detector separations are also presented to reveal the sampling depth profile of the fiber-optic probe geometry simulated. The modeling studies presented provide a framework to meaningfully interpret optical signals obtained from epithelial tissues and to optimize design of optical sensors for in vivo reflectance measurements for precancer detection. Results from this study can facilitate development of analytical photon propagation models that enable inverse estimation of diagnostically relevant optical parameters from in vivo reflectance measurements.
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Affiliation(s)
- Dizem Arifler
- Eastern Mediterranean University, Department of Physics, Famagusta, Cyprus
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Sharma D, Agrawal A, Matchette LS, Pfefer TJ. Evaluation of a fiberoptic-based system for measurement of optical properties in highly attenuating turbid media. Biomed Eng Online 2006; 5:49. [PMID: 16928274 PMCID: PMC1570472 DOI: 10.1186/1475-925x-5-49] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Accepted: 08/23/2006] [Indexed: 11/27/2022] Open
Abstract
Background Accurate measurements of the optical properties of biological tissue in the ultraviolet A and short visible wavelengths are needed to achieve a quantitative understanding of novel optical diagnostic devices. Currently, there is minimal information on optical property measurement approaches that are appropriate for in vivo measurements in highly absorbing and scattering tissues. We describe a novel fiberoptic-based reflectance system for measurement of optical properties in highly attenuating turbid media and provide an extensive in vitro evaluation of its accuracy. The influence of collecting reflectance at the illumination fiber on estimation accuracy is also investigated. Methods A neural network algorithm and reflectance distributions from Monte Carlo simulations were used to generate predictive models based on the two geometries. Absolute measurements of diffuse reflectance were enabled through calibration of the reflectance system. Spatially-resolved reflectance distributions were measured in tissue phantoms at 405 nm for absorption coefficients (μa) from 1 to 25 cm-1 and reduced scattering coefficients (μ′s
MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuaH8oqBgaqbamaaBaaaleaacqqGZbWCaeqaaaaa@3007@) from 5 to 25 cm-1. These data and predictive models were used to estimate the optical properties of tissue-simulating phantoms. Results By comparing predicted and known optical properties, the average errors for μa and μ′s
MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuaH8oqBgaqbamaaBaaaleaacqqGZbWCaeqaaaaa@3007@ were found to be 3.0% and 4.6%, respectively, for a linear probe approach. When bifurcated probe data was included and samples with μa values less than 5 cm-1 were excluded, predictive errors for μa and μ′s
MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuaH8oqBgaqbamaaBaaaleaacqqGZbWCaeqaaaaa@3007@ were further reduced to 1.8% and 3.5%. Conclusion Improvements in system design have led to significant reductions in optical property estimation error. While the incorporation of a bifurcated illumination fiber shows promise for improving the accuracy of μ′s
MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuaH8oqBgaqbamaaBaaaleaacqqGZbWCaeqaaaaa@3007@ estimates, further study of this approach is needed to elucidate the source of discrepancies between measurements and simulation results at low μa values.
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Affiliation(s)
- Divyesh Sharma
- Food and Drug Administration, Center for Devices and Radiological Health, Rockville, Maryland, USA
| | - Anant Agrawal
- Food and Drug Administration, Center for Devices and Radiological Health, Rockville, Maryland, USA
| | - L Stephanie Matchette
- Food and Drug Administration, Center for Devices and Radiological Health, Rockville, Maryland, USA
| | - T Joshua Pfefer
- Food and Drug Administration, Center for Devices and Radiological Health, Rockville, Maryland, USA
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Fletcher KA, Fakayode SO, Lowry M, Tucker SA, Neal SL, Kimaru IW, McCarroll ME, Patonay G, Oldham PB, Rusin O, Strongin RM, Warner IM. Molecular fluorescence, phosphorescence, and chemiluminescence spectrometry. Anal Chem 2006; 78:4047-68. [PMID: 16771540 PMCID: PMC2662353 DOI: 10.1021/ac060683m] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Hsu ER, Gillenwater AM, Hasan MQ, Williams MD, El-Naggar AK, Richards-Kortum RR. Real-time detection of epidermal growth factor receptor expression in fresh oral cavity biopsies using a molecular-specific contrast agent. Int J Cancer 2006; 118:3062-71. [PMID: 16395711 DOI: 10.1002/ijc.21720] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Early diagnosis of individuals with high risk of developing head and neck squamous carcinoma should lead to decreased morbidity and increased survival. To aid in noninvasive early detection of oral neoplasia in vivo, we have developed a molecular-specific fluorescent contrast agent, consisting of a far-red fluorescent dye coupled to a monoclonal antibody targeted against the epidermal growth factor receptor. In our study, we used organ cultures of normal and neoplastic human oral tissue to evaluate the capabilities of using this contrast agent to enhance clinical diagnosis. Fresh tissue sections were prepared from 34 biopsies of clinically normal and abnormal oral mucosa from 17 consenting patients. Samples were exposed to contrast agent, rinsed and the presence of bound agent was detected using fluorescence confocal microscopy. Simple assays to assess cytotoxicity of the dye used in the agent and to determine labeling efficacy at physiologic temperatures were also performed. Results indicate that the mean fluorescence intensity (MFI) of samples with dysplasia and cancer are higher than that of the normal sample from the same patient, and that this increase in fluorescence could potentially be used in the early detection and delineation of premalignant lesions. Normal tissue could be distinguished from cancer or moderate dysplasia, using either the ratio of the MFI of abnormal to normal tissue or the MFI obtained from the epithelial surface. No detrimental effects from the dye were observed over a 4-day period. These results indicate that the use of this optical contrast agent could yield important clinical advantages for noninvasive early detection and molecular characterization of oral mucosa.
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Affiliation(s)
- Elizabeth R Hsu
- Department of Biomedical Engineering, The University of Texas at Austin, 77251, USA
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Arifler D, Schwarz RA, Chang SK, Richards-Kortum R. Reflectance spectroscopy for diagnosis of epithelial precancer: model-based analysis of fiber-optic probe designs to resolve spectral information from epithelium and stroma. APPLIED OPTICS 2005; 44:4291-305. [PMID: 16045217 PMCID: PMC2773164 DOI: 10.1364/ao.44.004291] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Reflectance spectroscopy is a promising technology for detection of epithelial precancer. Fiber-optic probes that selectively collect scattered light from both the epithelium and the underlying stroma are likely to improve diagnostic performance of in vivo reflectance spectroscopy by revealing diagnostic features unique to each layer. We present Monte Carlo models with which to evaluate fiber-optic probe geometries with respect to sampling depth and depth resolution. We propose a probe design that utilizes half-ball lens coupled source and detector fibers to isolate epithelial scattering from stromal scattering and hence to resolve spectral information from the two layers. The probe is extremely compact and can provide easy access to different organ sites.
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Wang AMJ, Bender JE, Pfefer J, Utzinger U, Drezek RA. Depth-sensitive reflectance measurements using obliquely oriented fiber probes. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:44017. [PMID: 16178650 DOI: 10.1117/1.1989335] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Computer simulation is used to facilitate the design of fiber-probe geometries that enable enhanced detection of optical signals arising from specific tissue depths. Obtaining understanding of the relationship between fiber-probe design and tissue interrogation is critical when developing strategies for optical detection of epithelial precancers that originate at known depths from the tissue surface. The accuracy of spectroscopic diagnostics may be enhanced by discretely probing the optical properties of epithelium and underlying stroma, within which the morphological and biochemical features vary as a function of depth. While previous studies have investigated controlling tissue-probing depth for fluorescence-based modalities, in this study we focus on the detection of reflected light scattered by tissue. We investigate how the depth of optical interrogation may be controlled through combinations of collection angles, source-detector separations, and numerical apertures. We find that increasing the obliquity of collection fibers at a given source-detector separation can effectively enhance the detection of superficially scattered signals. Fiber numerical aperture provides additional depth selectivity; however, the perturbations in sampling depth achieved through this means are modest relative to the changes generated by modifying the angle of collection and source-detection separation.
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Pfefer TJ, Agrawal A, Drezek RA. Oblique-incidence illumination and collection for depth-selective fluorescence spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:44016. [PMID: 16178649 DOI: 10.1117/1.1989308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Optimization of device-tissue interface parameters may lead to an improvement in the efficacy of fluorescence spectroscopy for minimally invasive disease detection. Although illumination-collection geometry has been shown to have a strong influence on the spatial origin of detected fluorescence, devices that deliver and/or collect light at oblique incidence are not well understood. Simulations are performed using a Monte Carlo model of light propagation in homogeneous tissue to characterize general trends in the intensity and spatial origin of fluorescence detected by angled geometries. Specifically, the influence of illumination angle, collection angle, and illumination-collection spot separation distance are investigated for low and high attenuation tissue cases. Results indicate that oblique-incidence geometries have the potential to enhance the selective interrogation of superficial or subsurface fluorophores at user-selectable depths up to about 0.5 mm. Detected fluorescence intensity is shown to increase significantly with illumination and collection angle. Improved selectivity and signal intensity over normal-incidence geometries result from the overlap of illumination and collection cones within the tissue. Cases involving highly attenuating tissue produce a moderate reduction in the depth of signal origin. While Monte Carlo modeling indicates that oblique-incidence designs can facilitate depth-selective fluorescence spectroscopy, optimization of device performance will require application-specific consideration of optical and biological parameters.
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Affiliation(s)
- T Joshua Pfefer
- Food and Drug Administration FDA/CDRH/HFZ-130, Center for Devices and Radiological Health, 12725 Twinbrook Parkway, Rockville, Maryland 20852, USA.
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Schwarz RA, Arifler D, Chang SK, Pavlova I, Hussain IA, Mack V, Knight B, Richards-Kortum R, Gillenwater AM. Ball lens coupled fiber-optic probe for depth-resolved spectroscopy of epithelial tissue. OPTICS LETTERS 2005; 30:1159-61. [PMID: 15945140 PMCID: PMC2773162 DOI: 10.1364/ol.30.001159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A ball lens coupled fiber-optic probe design is described for depth-resolved measurements of the fluorescence and reflectance properties of epithelial tissue. A reflectance target, fluorescence targets, and a two-layer tissue phantom consisting of fluorescent microspheres suspended in collagen are used to characterize the performance of the probe. Localization of the signal to within 300 microm of the probe tip is observed by use of reflectance and fluorescence targets in air. Differential enhancement of the fluorescence signal from the top layer of the two-layer tissue phantom is observed.
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Affiliation(s)
- Richard A Schwarz
- Department of Biomedical Engineering, University of Texas at Austin, 1 University Station, C0800, Austin, Texas 78712, USA
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Skala MC, Squirrell JM, Vrotsos KM, Eickhoff JC, Gendron-Fitzpatrick A, Eliceiri KW, Ramanujam N. Multiphoton microscopy of endogenous fluorescence differentiates normal, precancerous, and cancerous squamous epithelial tissues. Cancer Res 2005; 65:1180-6. [PMID: 15735001 PMCID: PMC4189807 DOI: 10.1158/0008-5472.can-04-3031] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study characterizes the morphologic features and the endogenous fluorescence in the stratified squamous epithelia of the 7,12-dimethylbenz(a)anthracene-treated hamster cheek pouch model of carcinogenesis using multiphoton laser scanning microscopy (MPLSM). MPLSM allows high-resolution, three-dimensional image data to be collected deeper within thick tissue samples with reduced phototoxicity compared with single-photon imaging. Three-dimensional image stacks of normal (n = 13), precancerous (dysplasia, n = 12; carcinoma in situ, n = 9) and cancerous tissue [nonpapillary squamous cell carcinoma (SCC), n = 10, and papillary SCC, n = 7] sites in the hamster cheek pouch were collected in viable, unsectioned tissue biopsies at a two-photon excitation wavelength of 780 nm. Five features were quantified from the MPLSM images. These included nuclear density versus depth, keratin layer thickness, epithelial thickness, and the fluorescence per voxel in the keratin and epithelial layers. Statistically significant differences in all five features were found between normal and both precancerous and cancerous tissues. The only exception to this was a lack of statistically significant differences in the keratin fluorescence between normal tissues and papillary SCCs. Statistically significant differences were also observed in the epithelial thickness of dysplasia and carcinoma in situ, and in the keratin layer thickness of dysplasia and SCCs (both nonpapillary and papillary). This work clearly shows that three-dimensional images from MPLSM of endogenous tissue fluorescence can effectively distinguish between normal, precancerous, and cancerous epithelial tissues. This study provides the groundwork for further exploration into the application of multiphoton fluorescence endoscopy in a clinical setting.
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Affiliation(s)
- Melissa C. Skala
- Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin
| | - Jayne M. Squirrell
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, Wisconsin
| | - Kristin M. Vrotsos
- Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin
| | - Jens C. Eickhoff
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin
| | | | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, Wisconsin
| | - Nirmala Ramanujam
- Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin
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Liu Q, Ramanujam N. Experimental proof of the feasibility of using an angled fiber-optic probe for depth-sensitive fluorescence spectroscopy of turbid media. OPTICS LETTERS 2004; 29:2034-2036. [PMID: 15455771 DOI: 10.1364/ol.29.002034] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An angled fiber-optic probe that facilitates depth-sensitive fluorescence measurements was developed for enhancing detection of epithelial precancers. The probe was tested on solid, two-layered phantoms and proved to be effective in selectively detecting fluorescence from different layers. Specifically, a larger illumination angle provides greater sensitivity to fluorescence from the top layer as well as yielding an overall higher fluorescence signal. Monte Carlo simulations of a theoretical model of the phantoms demonstrate that increasing the illumination angle results in an increased excitation photon density and, thus, in increased fluorescence generated in the top layer.
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Affiliation(s)
- Quan Liu
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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