1
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Matheson AB, Hopkinson C, Tanner MG, Henderson RK. Fluorescence lifetime imaging with distance and ranging using a miniaturised SPAD system. Sci Rep 2024; 14:13285. [PMID: 38858419 PMCID: PMC11164884 DOI: 10.1038/s41598-024-63409-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/28/2024] [Indexed: 06/12/2024] Open
Abstract
In this work we demonstrate a miniaturised imaging system based around a time-gated SPAD array operating in a "chip-on-tip" manner. Two versions of the system are demonstrated, each measuring 23 mm × 23 mm × 28 mm with differing fields of view and working distances. Initial tests demonstrate contrast between materials in widefield fluorescence imaging (WFLIm) mode, with frame rates of > 2 Hz achievable. Following this, WFLIm images of autofluorescence in ovine lung tissue are obtained at frame rates of ~ 1 Hz. Finally, the ability of the second system to perform simultaneous WFLIm and time of flight (aka Flourescence Lifetime Imaging Distance and Ranging, FLImDAR) is also tested. This shows that the system is capable of 4 mm resolution of object separation when tested on 3D printed samples. It is further demonstrated as being able to perform scene reconstruction on autofluorescent lung tissue. This system is, to date, the smallest chip on tip WFLIm system published, and is the first demonstration of the FLImDAR technique in a compact, portable system.
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Affiliation(s)
- Andrew B Matheson
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, EH9 3FF, UK.
| | - Charlotte Hopkinson
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Michael G Tanner
- School of Engineering and Physical Sciences, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Robert K Henderson
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, EH9 3FF, UK
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2
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Hopkinson C, Matheson AB, Finlayson N, Tanner MG, Akram AR, Henderson RK. Combined fluorescence lifetime and surface topographical imaging of biological tissue. BIOMEDICAL OPTICS EXPRESS 2024; 15:212-221. [PMID: 38223190 PMCID: PMC10783922 DOI: 10.1364/boe.504309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 11/03/2023] [Accepted: 11/05/2023] [Indexed: 01/16/2024]
Abstract
In this work a combined fluorescence lifetime and surface topographical imaging system is demonstrated. Based around a 126 × 192 time resolved single photon avalanche diode (SPAD) array operating in time correlated single-photon counting (TCSPC) mode, both the fluorescence lifetime and time of flight (ToF) can be calculated on a pixel by pixel basis. Initial tests on fluorescent samples show it is able to provide 4 mm resolution in distance and 0.4 ns resolution in lifetime. This combined modality has potential biomedical applications such as surgical guidance, endoscopy, and diagnostic imaging. The system is demonstrated on both ovine and human pulmonary tissue samples, where it offers excellent fluorescence lifetime contrast whilst also giving a measure of the distance to the sample surface.
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Affiliation(s)
- Charlotte Hopkinson
- Institute for Integrated Micro and Nano
Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Andrew B. Matheson
- Institute for Integrated Micro and Nano
Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Neil Finlayson
- Institute for Integrated Micro and Nano
Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Michael G. Tanner
- Institute of Photonics and Quantum
Sciences, School of Engineering and Physical Sciences,
Heriot-Watt University, Edinburgh EH14 4AS,
UK
| | - Ahsan R. Akram
- Centre for Inflammation Research, Institute
of Regeneration and Repair, University of Edinburgh, Edinburgh BioQuarter, Edinburgh EH16 4UU,
UK
| | - Robert K. Henderson
- Institute for Integrated Micro and Nano
Systems, School of Engineering, University of Edinburgh, Edinburgh EH9 3FF, UK
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3
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Smith JT, Aguénounon E, Gioux S, Intes X. Macroscopic fluorescence lifetime topography enhanced via spatial frequency domain imaging. OPTICS LETTERS 2020; 45:4232-4235. [PMID: 32735266 PMCID: PMC7935427 DOI: 10.1364/ol.397605] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report on a macroscopic fluorescence lifetime imaging (MFLI) topography computational framework based around machine learning with the main goal of retrieving the depth of fluorescent inclusions deeply seated in bio-tissues. This approach leverages the depth-resolved information inherent to time-resolved fluorescence data sets coupled with the retrieval of in situ optical properties as obtained via spatial frequency domain imaging (SFDI). Specifically, a Siamese network architecture is proposed with optical properties (OPs) and time-resolved fluorescence decays as input followed by simultaneous retrieval of lifetime maps and depth profiles. We validate our approach using comprehensive in silico data sets as well as with a phantom experiment. Overall, our results demonstrate that our approach can retrieve the depth of fluorescence inclusions, especially when coupled with optical properties estimation, with high accuracy. We expect the presented computational approach to find great utility in applications such as optical-guided surgery.
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Affiliation(s)
- Jason T. Smith
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Enagnon Aguénounon
- University of Strasbourg, ICube Laboratory, 300 Boulevard Sebastien Brant, 67412 Illkirch, France
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, 300 Boulevard Sebastien Brant, 67412 Illkirch, France
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Corresponding author:
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Etrych T, Janoušková O, Chytil P. Fluorescence Imaging as a Tool in Preclinical Evaluation of Polymer-Based Nano-DDS Systems Intended for Cancer Treatment. Pharmaceutics 2019; 11:E471. [PMID: 31547308 PMCID: PMC6781319 DOI: 10.3390/pharmaceutics11090471] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/29/2019] [Accepted: 09/04/2019] [Indexed: 01/04/2023] Open
Abstract
Targeted drug delivery using nano-sized carrier systems with targeting functions to malignant and inflammatory tissue and tailored controlled drug release inside targeted tissues or cells has been and is still intensively studied. A detailed understanding of the correlation between the pharmacokinetic properties and structure of the nano-sized carrier is crucial for the successful transition of targeted drug delivery nanomedicines into clinical practice. In preclinical research in particular, fluorescence imaging has become one of the most commonly used powerful imaging tools. Increasing numbers of suitable fluorescent dyes that are excitable in the visible to near-infrared (NIR) wavelengths of the spectrum and the non-invasive nature of the method have significantly expanded the applicability of fluorescence imaging. This chapter summarizes non-invasive fluorescence-based imaging methods and discusses their potential advantages and limitations in the field of drug delivery, especially in anticancer therapy. This chapter focuses on fluorescent imaging from the cellular level up to the highly sophisticated three-dimensional imaging modality at a systemic level. Moreover, we describe the possibility for simultaneous treatment and imaging using fluorescence theranostics and the combination of different imaging techniques, e.g., fluorescence imaging with computed tomography.
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Affiliation(s)
- Tomáš Etrych
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic.
| | - Olga Janoušková
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Petr Chytil
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
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5
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Miller JP, Maji D, Lam J, Tromberg BJ, Achilefu S. Noninvasive depth estimation using tissue optical properties and a dual-wavelength fluorescent molecular probe in vivo. BIOMEDICAL OPTICS EXPRESS 2017; 8:3095-3109. [PMID: 28663929 PMCID: PMC5480452 DOI: 10.1364/boe.8.003095] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/21/2017] [Accepted: 05/25/2017] [Indexed: 05/28/2023]
Abstract
Translation of fluorescence imaging using molecularly targeted imaging agents for real-time assessment of surgical margins in the operating room requires a fast and reliable method to predict tumor depth from planar optical imaging. Here, we developed a dual-wavelength fluorescent molecular probe with distinct visible and near-infrared excitation and emission spectra for depth estimation in mice and a method to predict the optical properties of the imaging medium such that the technique is applicable to a range of medium types. Imaging was conducted at two wavelengths in a simulated blood vessel and an in vivo tumor model. Although the depth estimation method was insensitive to changes in the molecular probe concentration, it was responsive to the optical parameters of the medium. Results of the intra-tumor fluorescent probe injection showed that the average measured tumor sub-surface depths were 1.31 ± 0.442 mm, 1.07 ± 0.187 mm, and 1.42 ± 0.182 mm, and the average estimated sub-surface depths were 0.97 ± 0.308 mm, 1.11 ± 0.428 mm, 1.21 ± 0.492 mm, respectively. Intravenous injection of the molecular probe allowed for selective tumor accumulation, with measured tumor sub-surface depths of 1.28 ± 0.168 mm, and 1.50 ± 0.394 mm, and the estimated depths were 1.46 ± 0.314 mm, and 1.60 ± 0.409 mm, respectively. Expansion of our technique by using material optical properties and mouse skin optical parameters to estimate the sub-surface depth of a tumor demonstrated an agreement between measured and estimated depth within 0.38 mm and 0.63 mm for intra-tumor and intravenous dye injections, respectively. Our results demonstrate the feasibility of dual-wavelength imaging for determining the depth of blood vessels and characterizing the sub-surface depth of tumors in vivo.
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Affiliation(s)
- Jessica P. Miller
- Optical Radiology Lab, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 4515 McKinley Ave, St. Louis, Missouri 63110, USA
- Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
- Co-contributing first authors contributed equally
| | - Dolonchampa Maji
- Optical Radiology Lab, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 4515 McKinley Ave, St. Louis, Missouri 63110, USA
- Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
- Co-contributing first authors contributed equally
| | - Jesse Lam
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Bruce J. Tromberg
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Samuel Achilefu
- Optical Radiology Lab, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 4515 McKinley Ave, St. Louis, Missouri 63110, USA
- Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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6
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Fluorescence optical imaging in anticancer drug delivery. J Control Release 2016; 226:168-81. [PMID: 26892751 DOI: 10.1016/j.jconrel.2016.02.022] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 02/10/2016] [Accepted: 02/11/2016] [Indexed: 12/21/2022]
Abstract
In the past several decades, nanosized drug delivery systems with various targeting functions and controlled drug release capabilities inside targeted tissues or cells have been intensively studied. Understanding their pharmacokinetic properties is crucial for the successful transition of this research into clinical practice. Among others, fluorescence imaging has become one of the most commonly used imaging tools in pre-clinical research. The development of increasing numbers of suitable fluorescent dyes excitable in the visible to near-infrared wavelengths of the spectrum has significantly expanded the applicability of fluorescence imaging. This paper focuses on the potential applications and limitations of non-invasive imaging techniques in the field of drug delivery, especially in anticancer therapy. Fluorescent imaging at both the cellular and systemic levels is discussed in detail. Additionally, we explore the possibility for simultaneous treatment and imaging using theranostics and combinations of different imaging techniques, e.g., fluorescence imaging with computed tomography.
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7
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Mu Y, Niedre M. Fast single photon avalanche photodiode-based time-resolved diffuse optical tomography scanner. BIOMEDICAL OPTICS EXPRESS 2015; 6:3596-3609. [PMID: 26417526 PMCID: PMC4574682 DOI: 10.1364/boe.6.003596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
Resolution in diffuse optical tomography (DOT) is a persistent problem and is primarily limited by high degree of light scatter in biological tissue. We showed previously that the reduction in photon scatter between a source and detector pair at early time points following a laser pulse in time-resolved DOT is highly dependent on the temporal response of the instrument. To this end, we developed a new single-photon avalanche photodiode (SPAD) based time-resolved DOT scanner. This instrument uses an array of fast SPADs, a femto-second Titanium Sapphire laser and single photon counting electronics. In combination, the overall instrument temporal impulse response function width was 59 ps. In this paper, we report the design of this instrument and validate its operation in symmetrical and irregularly shaped optical phantoms of approximately small animal size. We were able to accurately reconstruct the size and position of up to 4 absorbing inclusions, with increasing image quality at earlier time windows. We attribute these results primarily to the rapid response time of our instrument. These data illustrate the potential utility of fast SPAD detectors in time-resolved DOT.
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Affiliation(s)
- Ying Mu
- Department of Electrical and Computer Engineering, Dana Research Center, Northeastern University, Boston, MA, 02115, USA
| | - Mark Niedre
- Department of Electrical and Computer Engineering, Dana Research Center, Northeastern University, Boston, MA, 02115, USA
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8
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Kolste KK, Kanick SC, Valdés PA, Jermyn M, Wilson BC, Roberts DW, Paulsen KD, Leblond F. Macroscopic optical imaging technique for wide-field estimation of fluorescence depth in optically turbid media for application in brain tumor surgical guidance. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:26002. [PMID: 25652704 PMCID: PMC4405086 DOI: 10.1117/1.jbo.20.2.026002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/05/2015] [Indexed: 05/13/2023]
Abstract
A diffuse imaging method is presented that enables wide-field estimation of the depth of fluorescent molecular markers in turbid media by quantifying the deformation of the detected fluorescence spectra due to the wavelength-dependent light attenuation by overlying tissue. This is achieved by measuring the ratio of the fluorescence at two wavelengths in combination with normalization techniques based on diffuse reflectance measurements to evaluate tissue attenuation variations for different depths. It is demonstrated that fluorescence topography can be achieved up to a 5 mm depth using a near-infrared dye with millimeter depth accuracy in turbid media having optical properties representative of normal brain tissue. Wide-field depth estimates are made using optical technology integrated onto a commercial surgical microscope, making this approach feasible for real-world applications.
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Affiliation(s)
- Kolbein K. Kolste
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Stephen C. Kanick
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Pablo A. Valdés
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
- Dartmouth College, Geisel School of Medicine, Hanover, 1 Rope Ferry Road, New Hampshire 03755, United States
| | - Michael Jermyn
- Polytechnique Montreal, Engineering Physics Department, Montreal, Québec H3C 3A7, Canada
| | - Brian C. Wilson
- University of Toronto, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada
| | - David W. Roberts
- Dartmouth-Hitchcock Medical Center, Section of Neurosurgery, 1 Medical Center Drive, Lebanon, New Hampshire 03756, United States
| | - Keith D. Paulsen
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Frederic Leblond
- Polytechnique Montreal, Engineering Physics Department, Montreal, Québec H3C 3A7, Canada
- Address all correspondence to: Frederic Leblond, E-mail:
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Harbater O, Gannot I. Fluorescent probes concentration estimation in vitro and ex vivo as a model for early detection of Alzheimer's disease. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:127007. [PMID: 25545342 DOI: 10.1117/1.jbo.19.12.127007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 12/01/2014] [Indexed: 05/12/2023]
Abstract
The pathogenic process of Alzheimer's disease (AD) begins years before clinical diagnosis. Here, we suggest a method that may detect AD several years earlier than current exams. The method is based on previous reports that relate the concentration ratio of biomarkers (amyloid-beta and tau) in the cerebrospinal fluid (CSF) to the development of AD. Our method replaces the lumbar puncture process required for CSF drawing by using fluorescence measurements. The system uses an optical fiber coupled to a laser source and a detector. The laser radiation excites two fluorescent probes which may bond to the CSF biomarkers. Their concentration ratio is extracted from the fluorescence intensities and can be used for future AD detection. First, we present a theoretical model for fluorescence concentration ratio estimation. The method's feasibility was validated using Monte Carlo simulations. Its accuracy was then tested using multilayered tissue phantoms simulating the epidural fat, CSF, and bone. These phantoms have various optical properties, thicknesses, and fluorescence concentrations in order to simulate human anatomy variations and different fiber locations. The method was further tested using ex vivo chicken tissue. The average errors of the estimated concentration ratios were low both in vitro (4.4%) and ex vivo (10.9%), demonstrating high accuracy.
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Affiliation(s)
- Osnat Harbater
- Tel-Aviv University, Department of Biomedical Engineering, Ramat Aviv, Tel-Aviv 69978, Israel
| | - Israel Gannot
- Tel-Aviv University, Department of Biomedical Engineering, Ramat Aviv, Tel-Aviv 69978, IsraelbJohns Hopkins University, Department of Electrical and Computer Engineering, School Engineering, Baltimore, Maryland 21218, United States
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10
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Abstract
Diffuse optical imaging is highly versatile and has a very broad range of applications in biology and medicine. It covers diffuse optical tomography, fluorescence diffuse optical tomography, bioluminescence, and a number of other new imaging methods. These methods of diffuse optical imaging have diversified instrument configurations but share the same core physical principle – light propagation in highly diffusive media, i.e., the biological tissue. In this review, the author summarizes the latest development in instrumentation and methodology available to diffuse optical imaging in terms of system architecture, light source, photo-detection, spectral separation, signal modulation, and lastly imaging contrast.
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Pichette J, Domínguez JB, Bérubé-Lauzière Y. Time-domain geometrical localization of point-like fluorescence inclusions in turbid media with early photon arrival times. APPLIED OPTICS 2013; 52:5985-5999. [PMID: 24085003 DOI: 10.1364/ao.52.005985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/23/2013] [Indexed: 06/02/2023]
Abstract
We introduce a novel approach for localizing a plurality of discrete point-like fluorescent inclusions embedded in a thick turbid medium using time-domain measurements. The approach uses early photon information contained in measured time-of-flight distributions originating from fluorescence emission. Fluorescence time point-spread functions (FTPSFs) are acquired with ultrafast time-correlated single photon counting after short pulse laser excitation. Early photon arrival times are extracted from the FTPSFs obtained from several source-detector positions. Each source-detector measurement allows defining a geometrical locus where an inclusion is to be found. These loci take the form of ovals in 2D or ovoids in 3D. From these loci a map can be built, with the maxima thereof corresponding to positions of inclusions. This geometrical approach is supported by Monte Carlo simulations performed for biological tissue-like media with embedded fluorescent inclusions. To validate the approach, several experiments are conducted with a homogeneous phantom mimicking tissue optical properties. In the experiments, inclusions filled with indocyanine green are embedded in the phantom and the fluorescence response to a short pulse of excitation laser is recorded. With our approach, several inclusions can be localized with low millimeter positional error. Our results support the approach as an accurate, efficient, and fast method for localizing fluorescent inclusions embedded in highly turbid media mimicking biological tissues. Further Monte Carlo simulations on a realistic mouse model show the feasibility of the technique for small animal imaging.
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Mo W, Rohrbach D, Sunar U. Imaging a photodynamic therapy photosensitizer in vivo with a time-gated fluorescence tomography system. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:071306. [PMID: 22894467 PMCID: PMC3381019 DOI: 10.1117/1.jbo.17.7.071306] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 02/20/2012] [Accepted: 03/05/2012] [Indexed: 05/29/2023]
Abstract
We report the tomographic imaging of a photodynamic therapy (PDT) photosensitizer, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) in vivo with time-domain fluorescence diffuse optical tomography (TD-FDOT). Simultaneous reconstruction of fluorescence yield and lifetime of HPPH was performed before and after PDT. The methodology was validated in phantom experiments, and depth-resolved in vivo imaging was achieved through simultaneous three-dimensional (3-D) mappings of fluorescence yield and lifetime contrasts. The tomographic images of a human head-and-neck xenograft in a mouse confirmed the preferential uptake and retention of HPPH by the tumor 24-h post-injection. HPPH-mediated PDT induced significant changes in fluorescence yield and lifetime. This pilot study demonstrates that TD-FDOT may be a good imaging modality for assessing photosensitizer distributions in deep tissue during PDT monitoring.
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Affiliation(s)
- Weirong Mo
- Roswell Park Cancer Institute, Department of Cell Stress Biology and PDT Center, Elm and Carlton Streets, Buffalo, New York, 14263
| | - Daniel Rohrbach
- Roswell Park Cancer Institute, Department of Cell Stress Biology and PDT Center, Elm and Carlton Streets, Buffalo, New York, 14263
| | - Ulas Sunar
- Roswell Park Cancer Institute, Department of Cell Stress Biology and PDT Center, Elm and Carlton Streets, Buffalo, New York, 14263
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In vivo fluorescence lifetime imaging monitors binding of specific probes to cancer biomarkers. PLoS One 2012; 7:e31881. [PMID: 22384092 PMCID: PMC3285647 DOI: 10.1371/journal.pone.0031881] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 01/19/2012] [Indexed: 11/19/2022] Open
Abstract
One of the most important factors in choosing a treatment strategy for cancer is characterization of biomarkers in cancer cells. Particularly, recent advances in Monoclonal Antibodies (MAB) as primary-specific drugs targeting tumor receptors show that their efficacy depends strongly on characterization of tumor biomarkers. Assessment of their status in individual patients would facilitate selection of an optimal treatment strategy, and the continuous monitoring of those biomarkers and their binding process to the therapy would provide a means for early evaluation of the efficacy of therapeutic intervention. In this study we have demonstrated for the first time in live animals that the fluorescence lifetime can be used to detect the binding of targeted optical probes to the extracellular receptors on tumor cells in vivo. The rationale was that fluorescence lifetime of a specific probe is sensitive to local environment and/or affinity to other molecules. We attached Near-InfraRed (NIR) fluorescent probes to Human Epidermal Growth Factor 2 (HER2/neu)-specific Affibody molecules and used our time-resolved optical system to compare the fluorescence lifetime of the optical probes that were bound and unbound to tumor cells in live mice. Our results show that the fluorescence lifetime changes in our model system delineate HER2 receptor bound from the unbound probe in vivo. Thus, this method is useful as a specific marker of the receptor binding process, which can open a new paradigm in the “image and treat” concept, especially for early evaluation of the efficacy of the therapy.
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Ardeshirpour Y, Chernomordik V, Capala J, Hassan M, Zielinsky R, Griffiths G, Achilefu S, Smith P, Gandjbakhckhe A. Using in-vivo fluorescence imaging in personalized cancer diagnostics and therapy, an image and treat paradigm. Technol Cancer Res Treat 2011; 10:549-60. [PMID: 22066595 PMCID: PMC3718028 DOI: 10.1177/153303461101000605] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The major goal in developing drugs targeting specific tumor receptors, such as Monoclonal AntiBodies (MAB), is to make a drug compound that targets selectively the cancer-causing biomarkers, inhibits their functionality, and/or delivers the toxin specifically to the malignant cells. Recent advances in MABs show that their efficacy depends strongly on characterization of tumor biomarkers. Therefore, one of the main tasks in cancer diagnostics and treatment is to develop non-invasive in-vivo imaging techniques for detection of cancer biomarkers and monitoring their down regulation during the treatment. Such methods can potentially result in a new imaging and treatment paradigm for cancer therapy. In this article we have reviewed fluorescence imaging approaches, including those developed in our group, to detect and monitor Human Epidermal Growth Factor 2 (HER2) receptors before and during therapy. Transition of these techniques from the bench to bedside is the ultimate goal of our project. Similar approaches can be used potentially for characterization of other cancer related cell biomarkers.
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Affiliation(s)
- Yasaman Ardeshirpour
- NIH/National Institute of Child Health and Human Development, Building 9, 9 Memorial Dr., Bethesda, MD, 20892
| | - Victor Chernomordik
- NIH/National Institute of Child Health and Human Development, Building 9, 9 Memorial Dr., Bethesda, MD, 20892
| | - Jacek Capala
- NIH/National Cancer Institute, Building 10-Magnuson Clinical Center, 10 Center Dr, Bethesda, MD, 20892
| | - Moinuddin Hassan
- NIH/National Institute of Child Health and Human Development, Building 9, 9 Memorial Dr., Bethesda, MD, 20892
| | - Rafal Zielinsky
- NIH/National Cancer Institute, Building 10-Magnuson Clinical Center, 10 Center Dr, Bethesda, MD, 20892
| | - Gary Griffiths
- NIH/Imaging Probe Development Center, Building 9800, Medical Center Dr., Rockville, MD, 20850
| | - Samuel Achilefu
- Optical Radiology Lab, Department of Radiology, Washington University, 4525 Scott Avenue, St. Louis, MO 63110
| | - Paul Smith
- NIH/National Institute of Biomedical Imaging and Bioengineering, Building 13, 3N18A 13 South Dr, Bethesda, MD, 20892
| | - Amir Gandjbakhckhe
- NIH/National Institute of Child Health and Human Development, Building 9, 9 Memorial Dr., Bethesda, MD, 20892
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Leblond F, Ovanesyan Z, Davis SC, Valdés PA, Kim A, Hartov A, Wilson BC, Pogue BW, Paulsen KD, Roberts DW. Analytic expression of fluorescence ratio detection correlates with depth in multi-spectral sub-surface imaging. Phys Med Biol 2011; 56:6823-37. [PMID: 21971201 DOI: 10.1088/0031-9155/56/21/005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Here we derived analytical solutions to diffuse light transport in biological tissue based on spectral deformation of diffused near-infrared measurements. These solutions provide a closed-form mathematical expression which predicts that the depth of a fluorescent molecule distribution is linearly related to the logarithm of the ratio of fluorescence at two different wavelengths. The slope and intercept values of the equation depend on the intrinsic values of absorption and reduced scattering of tissue. This linear behavior occurs if the following two conditions are satisfied: the depth is beyond a few millimeters and the tissue is relatively homogeneous. We present experimental measurements acquired with a broad-beam non-contact multi-spectral fluorescence imaging system using a hemoglobin-containing diffusive phantom. Preliminary results confirm that a significant correlation exists between the predicted depth of a distribution of protoporphyrin IX molecules and the measured ratio of fluorescence at two different wavelengths. These results suggest that depth assessment of fluorescence contrast can be achieved in fluorescence-guided surgery to allow improved intra-operative delineation of tumor margins.
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Affiliation(s)
- F Leblond
- Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755, USA.
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Tichauer KM, Migueis M, Leblond F, Elliott JT, Diop M, St Lawrence K, Lee TY. Depth resolution and multiexponential lifetime analyses of reflectance-based time-domain fluorescence data. APPLIED OPTICS 2011; 50:3962-3972. [PMID: 21772380 DOI: 10.1364/ao.50.003962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Time-domain fluorescence imaging is a powerful new technique that adds a rich amount of information to conventional fluorescence imaging. Specifically, time-domain fluorescence can be used to remove autofluorescence from signals, resolve multiple fluorophore concentrations, provide information about tissue microenvironments, and, for reflectance-based imaging systems, resolve inclusion depth. The present study provides the theory behind an improved method of analyzing reflectance-based time-domain data that is capable of accurately recovering mixed concentration ratios of multiple fluorescent agents while also recovering the depth of the inclusion. The utility of the approach was demonstrated in a number of simulations and in tissuelike phantom experiments using a short source-detector separation system. The major findings of this study were (1) both depth of an inclusion and accurate ratios of two-fluorophore concentrations can be recovered accurately up to depths of approximately 1 cm with only the optical properties of the medium as prior knowledge, (2) resolving the depth and accounting for the dispersion effects on fluorescent lifetimes is crucial to the accuracy of recovered ratios, and (3) ratios of three-fluorophore concentrations can be resolved at depth but only if the lifetimes of the three fluorophores are used as prior knowledge. By accurately resolving the concentration ratios of two to three fluorophores, it may be possible to remove autofluorescence or carry out quantitative techniques, such as reference tracer kinetic modeling or ratiometric approaches, to determine receptor binding or microenvironment parameters in point-based time-domain fluorescence applications.
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Affiliation(s)
- Kenneth M Tichauer
- Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario N6A 4V2, Canada.
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17
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Boffety M, Allain M, Sentenac A, Massonneau M, Carminati R. Cramer-Rao analysis of steady-state and time-domain fluorescence diffuse optical imaging. BIOMEDICAL OPTICS EXPRESS 2011; 2:1626-36. [PMID: 21698024 PMCID: PMC3114229 DOI: 10.1364/boe.2.001626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 05/13/2011] [Accepted: 05/15/2011] [Indexed: 05/21/2023]
Abstract
Using a Cramer-Rao analysis, we study the theoretical performances of a time and spatially resolved fDOT imaging system for jointly estimating the position and the concentration of a point-wide fluorescent volume in a diffusive sample. We show that the fluorescence lifetime is a critical parameter for the precision of the technique. A time resolved fDOT system that does not use spatial information is also considered. In certain cases, a simple steady-state configuration may be as efficient as this time resolved fDOT system.
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Affiliation(s)
- M. Boffety
- Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, 75231 Paris Cedex 05,
France
- Laboratoire EM2C - Ecole Centrale Paris, CNRS, Grande Voie des Vignes, 92295 Châtenay-Malabry Cedex,
France
- Quidd S.A.S., 50 rue Ettore Bugatti, 76800 Saint Etienne du Rouvray,
France
| | - M. Allain
- Institut Fresnel - Université Aix Marseille, CNRS, Faculté de St Jérôme, 13397 Marseille Cedex 20,
France
| | - A. Sentenac
- Institut Fresnel - Université Aix Marseille, CNRS, Faculté de St Jérôme, 13397 Marseille Cedex 20,
France
| | - M. Massonneau
- Quidd S.A.S., 50 rue Ettore Bugatti, 76800 Saint Etienne du Rouvray,
France
| | - R. Carminati
- Institut Langevin, ESPCI ParisTech, CNRS UMR 7587, 10 rue Vauquelin, 75231 Paris Cedex 05,
France
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18
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Klose AD, Pöschinger T. Excitation-resolved fluorescence tomography with simplified spherical harmonics equations. Phys Med Biol 2011; 56:1443-69. [PMID: 21321388 DOI: 10.1088/0031-9155/56/5/015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescence tomography (FT) reconstructs the three-dimensional (3D) fluorescent reporter probe distribution inside biological tissue. These probes target molecules of biological function, e.g. cell surface receptors or enzymes, and emit fluorescence light upon illumination with an external light source. The fluorescence light is detected on the tissue surface and a source reconstruction algorithm based on the simplified spherical harmonics (SP(N)) equations calculates the unknown 3D probe distribution inside tissue. While current FT approaches require multiple external sources at a defined wavelength range, the proposed FT method uses only a white light source with tunable wavelength selection for fluorescence stimulation and further exploits the spectral dependence of tissue absorption for the purpose of 3D tomographic reconstruction. We will show the feasibility of the proposed hyperspectral excitation-resolved fluorescence tomography method with experimental data. In addition, we will demonstrate the performance and limitations of such a method under ideal and controlled conditions by means of a digital mouse model and synthetic measurement data. Moreover, we will address issues regarding the required amount of wavelength intervals for fluorescent source reconstruction. We will explore the impact of assumed spatially uniform and nonuniform optical parameter maps on the accuracy of the fluorescence source reconstruction. Last, we propose a spectral re-scaling method for overcoming the observed limitations in reconstructing accurate source distributions in optically non-uniform tissue when assuming only uniform optical property maps for the source reconstruction process.
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Affiliation(s)
- Alexander D Klose
- Department of Radiology, Columbia University Medical Center, New York, NY 10032, USA.
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19
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Han SH, Farshchi-Heydari S, Hall DJ. Analytical method for the fast time-domain reconstruction of fluorescent inclusions in vitro and in vivo. Biophys J 2010; 98:350-7. [PMID: 20338857 DOI: 10.1016/j.bpj.2009.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 09/16/2009] [Accepted: 10/07/2009] [Indexed: 10/19/2022] Open
Abstract
A novel time-domain optical method to reconstruct the relative concentration, lifetime, and depth of a fluorescent inclusion is described. We establish an analytical method for the estimations of these parameters for a localized fluorescent object directly from the simple evaluations of continuous wave intensity, exponential decay, and temporal position of the maximum of the fluorescence temporal point-spread function. Since the more complex full inversion process is not involved, this method permits a robust and fast processing in exploring the properties of a fluorescent inclusion. This method is confirmed by in vitro and in vivo experiments.
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Affiliation(s)
- Sung-Ho Han
- Department of Radiology and Moores UCSD Cancer Center, University of California at San Diego, La Jolla, California, USA.
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20
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Da Silva A, Djaker N, Ducros N, Dinten JM, Rizo P. Real time optical method for localization of inclusions embedded in turbid media. OPTICS EXPRESS 2010; 18:7753-7762. [PMID: 20588616 DOI: 10.1364/oe.18.007753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A simple and fast time-domain method for localizing inclusions, fluorescent optical probes or absorbers, is presented. The method offers new possibilities for situations where complete tomographic measurements are not permitted by the examined object, for example in endoscopic examination of the human prostate or the oesophagus. Feasibility has been envisioned with a phantom study conducted on a point-like fluorochrome embedded in a diffusing medium mimicking the optical properties of biological tissues.
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Affiliation(s)
- Anabela Da Silva
- CEA, LETI, micro-Technologies for Biology and Healthcare Division, 17 rue des Martyrs, F38054 Grenoble Cedex 9, France.
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21
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Hall DJ, Sunar U, Farshchi-Heydari S, Han SH. In vivo simultaneous monitoring of two fluorophores with lifetime contrast using a full-field time domain system. APPLIED OPTICS 2009; 48:D74-8. [PMID: 19340126 DOI: 10.1364/ao.48.000d74] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Optical molecular imaging of small animals in vivo has witnessed dramatic growth during the past decade. Most commercial systems are based on continuous wave technology and measure solely bioluminescence or fluorescence intensity. Time domain (TD) technology enables the measurement of both intensity and fluorescence lifetime as an additional imaging metric. We have developed a novel, in-house, full-field TD system with dramatically faster acquisition times than available from a commercial TD system. Recent in vivo data from a mouse imaged with the full-field TD system has demonstrated the potential to monitor and discriminate two fluorophores injected simultaneously based on their fluorescence lifetime contrast.
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Affiliation(s)
- David J Hall
- Department of Radiology, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, California 92093, USA.
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22
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Nothdurft RE, Patwardhan SV, Akers W, Ye Y, Achilefu S, Culver JP. In vivo fluorescence lifetime tomography. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:024004. [PMID: 19405734 DOI: 10.1117/1.3086607] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Local molecular and physiological processes can be imaged in vivo through perturbations in the fluorescence lifetime (FLT) of optical imaging agents. In addition to providing functional information, FLT methods can quantify specific molecular events and multiplex diagnostic and prognostic information. We have developed a fluorescence lifetime diffuse optical tomography (DOT) system for in vivo preclinical imaging. Data is captured using a time-resolved intensified charge coupled device (ICCD) system to measure fluorescence excitation and emission in the time domain. Data is then converted to the frequency domain, and we simultaneously reconstruct images of yield and lifetime using an extension to the normalized Born approach. By using differential phase measurements, we demonstrate DOT imaging of short lifetimes (from 350 ps) with high precision (+/-5 ps). Furthermore, this system retains the efficiency, speed, and flexibility of transmission geometry DOT. We demonstrate feasibility of FLT-DOT through a progressive series of experiments. Lifetime range and repeatability are first measured in phantoms. Imaging of subcutaneous implants then verifies the FLT-DOT approach in vivo in the presence of inhomogeneous optical properties. Use in a common research scenario is ultimately demonstrated by imaging accumulation of a targeted near-infrared (NIR) fluorescent-labeled peptide probe (cypate-RGD) in a mouse with a subcutaneous tumor.
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Affiliation(s)
- Ralph E Nothdurft
- Washington University School of Medicine, Department of Radiology, Mallinckrodt Institute of Radiology, St. Louis, Missouri 63110, USA
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23
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Abulrob A, Brunette E, Slinn J, Baumann E, Stanimirovic D. Dynamic Analysis of the Blood-Brain Barrier Disruption in Experimental Stroke Using Time Domain in Vivo Fluorescence Imaging. Mol Imaging 2008. [DOI: 10.2310/7290.2008.00025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The blood-brain barrier (BBB) disruption following cerebral ischemia can be exploited to deliver imaging agents and therapeutics into the brain. The aim of this study was (a) to establish novel in vivo optical imaging methods for longitudinal assessment of the BBB disruption and (b) to assess size selectivity and temporal patterns of the BBB disruption after a transient focal ischemia. The BBB permeability was assessed using in vivo time domain near-infrared optical imaging after contrast enhancement with either free Cy5.5 (1 kDa) or Cy5.5 conjugated with bovine serum albumin (BSA) (67 kDa) in mice subjected to either 60- or 20-minute transient middle cerebral artery occlusion (MCAO) and various times of reperfusion (up to 14 days). In vivo imaging observations were corroborated by ex vivo brain imaging and microscopic analyses of fluorescent tracer extravasation. The in vivo optical contrast enhancement with Cy5.5 was spatially larger than that observed with BSA-Cy5.5. Longitudinal studies after a transient 20-minute MCAO suggested a bilateral BBB disruption, more pronounced in the ipsilateral hemisphere, peaking at day 7 and resolving at day 14 after ischemia. The area differential between the BBB disruption for small and large molecules could potentially be useful as a surrogate imaging marker for assessing perinfarct tissues to which neuroprotective therapies of appropriate sizes could be delivered.
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Affiliation(s)
- Abedelnasser Abulrob
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Eric Brunette
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Jacqueline Slinn
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Ewa Baumann
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
| | - Danica Stanimirovic
- From the Cerebrovascular Research Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, ON
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24
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Han SH, Farshchi-Heydari S, Hall DJ. Analysis of the fluorescence temporal point-spread function in a turbid medium and its application to optical imaging. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:064038. [PMID: 19123684 DOI: 10.1117/1.3042271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A time-domain optical method to evaluate the concentration (n), lifetime (tau), and depth (d) of a fluorescent inclusion is described by the complete analysis of the fluorescence temporal point-spread function (TPSF). The behavior of parameters in the fluorescence TPSF is explored, and we demonstrate the method with experimental data from a localized fluorescent inclusion in scattering media to recover images of n, tau, and d. The method has potential application for in vivo fluorescence imaging.
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Affiliation(s)
- Sung-Ho Han
- University of California at San Diego, Moores Cancer Center and Department of Radiology, 3855 Health Sciences Drive, 0819, La Jolla, California 92093-0819, USA.
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25
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Abstract
A 3-chip CCD imaging system has been developed for quantitative in vivo fluorescence imaging. This incorporates a ratiometric algorithm to correct for the effects of tissue optical absorption and scattering, imaging “geometry” and tissue autofluorescence background. The performance was characterized, and the algorithm was validated in tissue-simulating optical phantoms for quantitative measurement of the fluorescent molecule protoporphyrin IX (PpIX). The technical feasibility to use this system for fluorescence-guided surgical resection of malignant brain tumor tissue was assessed in an animal model in which PpIX was induced exogenously in the tumor cells by systemic administration of aminolevulinic acid (ALA).
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26
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Marjono A, Yano A, Okawa S, Gao F, Yamada Y. Total light approach of time-domain fluorescence diffuse optical tomography. OPTICS EXPRESS 2008; 16:15268-85. [PMID: 18795065 DOI: 10.1364/oe.16.015268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In this study, time-domain fluorescence diffuse optical tomography in biological tissue is numerically investigated using a total light approach. Total light is a summation of excitation light and zero-lifetime emission light divided by quantum yield. The zero-lifetime emission light is an emitted fluorescence light calculated by assuming that the fluorescence lifetime is zero. The zero-lifetime emission light is calculated by deconvolving the actually measured emission light with a lifetime function, an exponential function for fluorescence decay. The object for numerical simulation is a 2-D 10 mm-radius circle with the optical properties simulating biological tissues for near infrared light, and contains regions with fluorophore. The inverse problem of fluorescence diffuse optical tomography is solved using time-resolved simulated measurement data of the excitation and total lights for reconstructing the bsorption coefficient and fluorophore concentration simultaneously. The mean time of flight is used as the featured data-type extracted from the time-resolved data. The reconstructed images of fluorophore concentration show good quantitativeness and spatial reproducibility. By use of the total light approach, computation is performed much faster than the conventional ones.
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Affiliation(s)
- Andhi Marjono
- Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, Chofu, Tokyo, Japan.
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27
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Akers WJ, Berezin MY, Lee H, Achilefu S. Predicting in vivo fluorescence lifetime behavior of near-infrared fluorescent contrast agents using in vitro measurements. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:054042. [PMID: 19021422 PMCID: PMC2744956 DOI: 10.1117/1.2982535] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Fluorescence lifetime (FLT) information is complementary to intensity measurement and can be used to improve signal-to-background contrast and provide environment sensing capability. In this study, we evaluate the FLTs of eight near-infrared fluorescent molecular probes in vitro in various solvent mediums and in vivo to establish the correlation between the in vitro and in vivo results. Compared with other mediums, two exponential fittings of the fluorescence decays of dyes dissolved in aqueous albumin solutions accurately predict the range of FLTs observed in vivo. We further demonstrate that the diffusion of a near-infrared (NIR) reporter from a dye-loaded gel can be detected by FLT change in mice as a model of controlled drug release. The mean FLT of the NIR probe increases as the dye diffuses from the highly polar gel interior to the more lipophilic tissue environment. The two-point analysis demonstrates an efficient in vitro method for screening new NIR fluorescent reporters for use as FLT probes in vivo, thereby minimizing the use of animals for FLT screening studies.
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Affiliation(s)
| | | | | | - Samuel Achilefu
- Address Correspondence to: Samuel Achilefu, PhD, Optical Radiology Lab, 4525 Scott Avenue, St. Louis, MO 63110, Telephone: 314-362-8599, Fax: 314-747-5191,
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28
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Riley J, Hassan M, Chernomordik V, Gandjbakhche A. Choice of data types in time resolved fluorescence enhanced diffuse optical tomography. Med Phys 2008; 34:4890-900. [PMID: 18196814 DOI: 10.1118/1.2804775] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In this paper we examine possible data types for time resolved fluorescence enhanced diffuse optical tomography (FDOT). FDOT is a particular case of diffuse optical tomography, where our goal is to analyze fluorophores deeply embedded in a turbid medium. We focus on the relative robustness of the different sets of data types to noise. We use an analytical model to generate the expected temporal point spread function (TPSF) and generate the data types from this. Varying levels of noise are applied to the TPSF before generating the data types. We show that local data types are more robust to noise than global data types, and should provide enhanced information to the inverse problem. We go on to show that with a simple reconstruction algorithm, depth and lifetime (the parameters of interest) of the fluorophore are better reconstructed using the local data types. Further we show that the relationship between depth and lifetime is better preserved for the local data types, suggesting they are in some way not only more robust, but also self-regularizing. We conclude that while the local data types may be more expensive to generate in the general case, they do offer clear advantages over the standard global data types.
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Affiliation(s)
- Jason Riley
- Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Building 9, Bethesda, Maryland 20892, USA.
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29
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Kumar ATN, Raymond SB, Dunn AK, Bacskai BJ, Boas DA. A time domain fluorescence tomography system for small animal imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2008; 27:1152-63. [PMID: 18672432 PMCID: PMC2920137 DOI: 10.1109/tmi.2008.918341] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We describe the application of a time domain diffuse fluorescence tomography system for whole body small animal imaging. The key features of the system are the use of point excitation in free space using ultrashort laser pulses and noncontact detection using a gated, intensified charge-coupled device (CCD) camera. Mouse shaped epoxy phantoms, with embedded fluorescent inclusions, were used to verify the performance of a recently developed asymptotic lifetime-based tomography algorithm. The asymptotic algorithm is based on a multiexponential analysis of the decay portion of the data. The multiexponential model is shown to enable the use of a global analysis approach for a robust recovery of the lifetime components present within the imaging medium. The surface boundaries of the imaging volume were acquired using a photogrammetric camera integrated with the imaging system, and implemented in a Monte-Carlo model of photon propagation in tissue. The tomography results show that the asymptotic approach is able to separate axially located fluorescent inclusions centered at depths of 4 and 10 mm from the surface of the mouse phantom. The fluorescent inclusions had distinct lifetimes of 0.5 and 0.95 ns. The inclusions were nearly overlapping along the measurement axis and shown to be not resolvable using continuous wave (CW) methods. These results suggest the practical feasibility and advantages of a time domain approach for whole body small animal fluorescence molecular imaging, particularly with the use of lifetime as a contrast mechanism.
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Affiliation(s)
- Anand T N Kumar
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
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30
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Han SH, Hall DJ. Estimating the depth and lifetime of a fluorescent inclusion in a turbid medium using a simple time-domain optical method. OPTICS LETTERS 2008; 33:1035-1037. [PMID: 18451978 DOI: 10.1364/ol.33.001035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A simple time-domain optical method for estimating the depth (d) and lifetime (tau) of fluorescent inclusions in a turbid medium is described. We demonstrate the method for depth and lifetime estimation of a fluorescent inclusion directly by fitting a monoexponential decay (tau(eff)) of the temporal position of the temporal point-spread function and the measurement of its maximum temporal position (t(max)). Since both of these measurements are intensity independent, this method provides a robust and efficient approach. This method is validated with experimental data.
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Affiliation(s)
- Sung-Ho Han
- Department of Radiology, University of California, San Diego, California 92093-0819, USA.
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31
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Chernomordik V, Hassan M, Amyot F, Riley J, Gandjbakhche A. Use of scaling relations to extract intrinsic fluorescence lifetime of targets embedded in turbid media. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:024025. [PMID: 18465988 DOI: 10.1117/1.2904660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a novel method for estimating the intrinsic fluorescence lifetime of deeply embedded localized fluorophores. It is based on scaling relations, characteristic for turbid media. The approach is experimentally substantiated by successfully reconstructing lifetimes for targets at depths up to 14.5 mm. A derived correction factor was determined from the product of the transport-corrected scattering coefficient mu(s) (') and the index of refraction n(r). In addition, data from an array of detectors (> or =2) can be used to estimate mu(s) (')n(r). The suggested algorithm is a promising tool for diagnostic fluorescence, since lifetime can be a sensitive indicator of the fluorophore environment.
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Affiliation(s)
- Victor Chernomordik
- National Institutes of Health, National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA.
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32
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Brambilla M, Spinelli L, Pifferi A, Torricelli A, Cubeddu R. Time-resolved scanning system for double reflectance and transmittance fluorescence imaging of diffusive media. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:013103. [PMID: 18248018 DOI: 10.1063/1.2828054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In this work we present a novel diffuse fluorescence imaging system, based on time-resolved two-wavelength double reflectance and transmittance setup for slab geometry samples. We describe the hardware setup, showing its compactness and versatility and show the results on preliminary measurements on phantoms. We fully assessed the performances and the dynamic ranges of the system. We validated its ability of recovering the optical properties of the bulk medium, for samples with scattering and absorption coefficients similar to those of biological tissues and with thicknesses of about 2 cm. Moreover we assess the linearity of the recorded signals against the fluorophore concentration, when it is homogeneously diffused in the phantom or concentrated inside a sealed inclusion. In both cases we observe again a fairly good linearity, over three orders of magnitude, from 10(-8)M to 10(-5)M. With the fluorescent inclusion we were also able to assess the imaging capabilities of the system, in terms of spatial resolution, which we appraise in about 3 mm, and in terms of imaging sensitivity (the smallest quantity of fluorescent dye distinguishable from the homogeneous background), settled to 200 fmol. Since the recorded data are time resolved, we could also estimate the dye fluorescence lifetime and build early and late time gate images. We finally discuss some of the criticalities of the proposed system and the developments we are currently carrying on in order to adapt it for in vivo measurements.
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Affiliation(s)
- Marco Brambilla
- IIT, ULTRAS-INFM-CNR and IFN-CNR, Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
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33
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Hassan M, Riley J, Chernomordik V, Smith P, Pursley R, Lee SB, Capala J, Amir H G. Fluorescence Lifetime Imaging System for in Vivo Studies. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00019] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this article, a fluorescence lifetime imaging system for small animals is presented. Data were collected by scanning a region of interest with a measurement head, a linear fiber array with fixed separations between a single source fiber and several detection fibers. The goal was to localize tumors and monitor their progression using specific fluorescent markers. We chose a near-infrared contrast agent, Alexa Fluor 750 (Invitrogen Corp., Carlsbad, CA). Preliminary results show that the fluorescence lifetime for this dye was sensitive to the immediate environment of the fluorophore (in particular, pH), making it a promising candidate for reporting physiologic changes around a fluorophore. To quantify the intrinsic lifetime of deeply embedded fluorophores, we performed phantom experiments to investigate the contribution of photon migration effects on observed lifetime by calculating the fluorescence intensity decay time. A previously proposed theoretical model of migration, based on random walk theory, is also substantiated by new experimental data. The developed experimental system has been used for in vivo mouse imaging with Alexa Fluor 750 contrast agent conjugated to tumor-specific antibodies (trastuzumab [Herceptin]). Three-dimensional mapping of the fluorescence lifetime indicates lower lifetime values in superficial breast cancer tumors in mice.
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Affiliation(s)
- Moinuddin Hassan
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Jason Riley
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Victor Chernomordik
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Paul Smith
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Randall Pursley
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Sang Bong Lee
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Jacek Capala
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Gandjbakhche Amir H
- From the Laboratory of Integrative and Medical Biophysics, National Institute of Child Health and Human Development; Office of Research Services; Center for Information Technology; and National Cancer Institute, National Institutes of Health, Bethesda, MD
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McCormack E, Micklem DR, Pindard LE, Silden E, Gallant P, Belenkov A, Lorens JB, Gjertsen BT. In Vivo Optical Imaging of Acute Myeloid Leukemia by Green Fluorescent Protein: Time-Domain Autofluorescence Decoupling, Fluorophore Quantification, and Localization. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Emmet McCormack
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - David R. Micklem
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - Lars-Erik Pindard
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - Elisabeth Silden
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - Pascal Gallant
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - Alexandre Belenkov
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - James B. Lorens
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
| | - Bjørn Tore Gjertsen
- From the Institute of Medicine, Haematology Section, Haukeland University Hospital, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; and ART Advanced Research Technologies Inc., Saint-Laurent, QC
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Laidevant A, Da Silva A, Berger M, Boutet J, Dinten JM, Boccara AC. Analytical method for localizing a fluorescent inclusion in a turbid medium. APPLIED OPTICS 2007; 46:2131-7. [PMID: 17384730 DOI: 10.1364/ao.46.002131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We describe a novel method for localizing a fluorescent inclusion in a homogeneous turbid medium through the use of time-resolved techniques. Based on the calculation of the mean time of the fluorescence curves, the method does not require a priori knowledge of either the fluorescence lifetime or the mean time of the instrument response function since it adopts a differential processing approach. Theoretical expressions were validated and experiments for assessing the accuracy of localization were carried out on liquid optical phantoms with a small fluorescent inclusion. The illumination and detection optical fibers were immersed in the medium to achieve infinite medium geometry as required by the model used. The experimental setup consisted of a time-correlated single-photon counting system. Submillimeter accuracy was achieved for the localization of the inclusion.
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Affiliation(s)
- A Laidevant
- Département micro Technologies pour la Biologie et la Santé, CEA-LETI Recherche Technologique Grenoble, Grenoble, France.
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Ma G, Delorme JF, Gallant P, Boas DA. Comparison of simplified Monte Carlo simulation and diffusion approximation for the fluorescence signal from phantoms with typical mouse tissue optical properties. APPLIED OPTICS 2007; 46:1686-92. [PMID: 17356611 DOI: 10.1364/ao.46.001686] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A simplified approach is proposed to simulate the fluorescence signal from a fluorophore submerged inside a turbid medium using the Monte Carlo method. Based on the reversibility of photon propagation, the fluorescence signal can be obtained from a single Monte Carlo simulation of the excitation light. This is computationally less expensive and also allows for the direct use of well-validated nonfluorescence photon migration Monte Carlo codes. Fluorescence signals from a mouse tissuelike phantom were computed using both the simplified Monte Carlo simulation and the diffusion approximation. The relative difference of signal intensity was found to be at most 30% for a fluorophore placed in the medium at various depths and horizontally midway between a source-detector pair separated by 3 mm. The difference in time characteristics of the signal is also examined.
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Affiliation(s)
- Guobin Ma
- Advance Research Technologies, Incorporated (ART), Canada.
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Ma G, Gallant P, McIntosh L. Sensitivity characterization of a time-domain fluorescence imager: eXplore Optix. APPLIED OPTICS 2007; 46:1650-7. [PMID: 17356607 DOI: 10.1364/ao.46.001650] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A key issue in the practical application of fluorescence imaging is the presence of a background signal detected during data acquisition when no target fluorescent material is present. Regardless of the technology employed, background signals cannot be completely eliminated, which limits the detection sensitivity of fluorescence imaging systems, especially for in vivo applications. We present a methodology to characterize the sensitivity of fluorescence imaging devices by taking the background effect into account through the fluorescent signal-to-background ratio (SBR). In an initial application of the methodology, tissuelike liquid phantoms with Cy5.5 fluorescent inclusions were investigated experimentally over a wide range of varying parameters, such as tissue absorption coefficient, scattering coefficient, fluorophore concentration, and inclusion location. By defining detectable and quantifiable SBR thresholds, empirical relations are established, and the sensitivity performance of Advanced Research Technologies's eXplore Optix using Cy5.5 is characterized.
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Affiliation(s)
- Guobin Ma
- Advanced Research Technologies, Incorporated, Canada.
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Abstract
There is a wealth of new fluorescent reporter technologies for tagging of many cellular and subcellular processes in vivo. This imposed contrast is now captured with an increasing number of available imaging methods that offer new ways to visualize and quantify fluorescent markers distributed in tissues. This is an evolving field of imaging sciences that has already achieved major advances but is also facing important challenges. It is nevertheless well poised to significantly impact the ways of biological research, drug discovery, and clinical practice in the years to come. Herein, the most pertinent technologies associated with in vivo noninvasive or minimally invasive fluorescence imaging of tissues are summarized. Focus is given to small-animal imaging. However, while a broad spectrum of fluorescence reporter technologies and imaging methods are outlined, as necessary for biomedical research, and clinical translation as well.
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Affiliation(s)
- Vasilis Ntziachristos
- Laboratory for Bio-Optics and Molecular Imaging, Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, 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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40
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Bloch S, Lesage F, McIntosh L, Gandjbakhche A, Liang K, Achilefu S. Whole-body fluorescence lifetime imaging of a tumor-targeted near-infrared molecular probe in mice. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:054003. [PMID: 16292963 DOI: 10.1117/1.2070148] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fluorescence lifetime imaging can provide valuable diagnostic information relating to the functional status of diseases. In this study, a near-infrared (NIR) dye-labeled hexapeptide (abbreviated Cyp-GRD) was synthesized. In vitro, Cyp-GRD internalized in nonsmall cell lung cancer cells (A549) without observable cytotoxic or proliferative effects to the cells at a concentration up to 1x10(-4) M. Time-domain fluorescence intensity and lifetime imaging of Cyp-GRD injected into A549 tumor-bearing mice revealed that the probe preferentially accumulated in the tumor and the major excretion organs. The fluorescence lifetime of the conjugate at the tumor site was mapped, showing the spatial distribution of the lifetime related to its environment. Additionally, fluorescence intensity image reconstruction obtained by integrating the time-resolved intensities enabled the contrast ratios of tumor-to-kidney or liver in slices at different depths to be displayed. The mean lifetime was 1.03 ns for the tumor and 0.80 ns for the liver when averaging those pixels exhibiting adequate signal-to-noise ratio, showing the tumor had a higher lifetime average and reflecting the altered physiopathology of the tumor. This study clearly demonstrated the feasibility of whole-body NIR fluorescence lifetime imaging for tumor localization and its spatial functional status in living small animals.
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Affiliation(s)
- Sharon Bloch
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri 63110, USA
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