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Konovalov AB, Vlasov VV, Uglov AS. Early-photon reflectance fluorescence molecular tomography for small animal imaging: Mathematical model and numerical experiment. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e03408. [PMID: 33094558 DOI: 10.1002/cnm.3408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 10/04/2020] [Accepted: 10/17/2020] [Indexed: 06/11/2023]
Abstract
The paper presents an original approach to time-domain reflectance fluorescence molecular tomography (FMT) of small animals. It is based on the use of early arriving photons and state-of-the-art compressed-sensing-like reconstruction algorithms and aims to improve the spatial resolution of fluorescent images. We deduce the fundamental equation that models the imaging operator and derive analytical representations for the sensitivity functions which are responsible for the reconstruction of the fluorophore absorption coefficient. The idea of fluorescence lifetime tomography with our approach is also discussed. We conduct a numerical experiment on 3D reconstruction of box phantoms with spherical fluorescent inclusions of small diameters. For modeling measurement data and constructing the sensitivity matrix we assume a virtual fluorescence tomograph with a scanning fiber probe that illuminates and collects light in reflectance geometry. It provides for large source-receiver separations which correspond to the macroscopic regime. Two compressed-sensing-like reconstruction algorithms are used to solve the inverse problem. These are the algebraic reconstruction technique with total variation regularization and our modification of the fast iterative shrinkage-thresholding algorithm. Results of our numerical experiment show that our approach is capable of achieving as good spatial resolution as 0.2 mm and even better at depths to 9 mm inclusive.
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Affiliation(s)
- Alexander B Konovalov
- Computational Center, Federal State Unitary Enterprise "Russian Federal Nuclear Center - Zababakhin All-Russia Research Institute of Technical Physics,", Snezhinsk, Russia
- Laboratory of Molecular Imaging, Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Vitaly V Vlasov
- Computational Center, Federal State Unitary Enterprise "Russian Federal Nuclear Center - Zababakhin All-Russia Research Institute of Technical Physics,", Snezhinsk, Russia
- Laboratory of Molecular Imaging, Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Alexander S Uglov
- Computational Center, Federal State Unitary Enterprise "Russian Federal Nuclear Center - Zababakhin All-Russia Research Institute of Technical Physics,", Snezhinsk, Russia
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Angelo JP, Chen SJ, Ochoa M, Sunar U, Gioux S, Intes X. Review of structured light in diffuse optical imaging. JOURNAL OF BIOMEDICAL OPTICS 2018; 24:1-20. [PMID: 30218503 PMCID: PMC6676045 DOI: 10.1117/1.jbo.24.7.071602] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/31/2018] [Indexed: 05/11/2023]
Abstract
Diffuse optical imaging probes deep living tissue enabling structural, functional, metabolic, and molecular imaging. Recently, due to the availability of spatial light modulators, wide-field quantitative diffuse optical techniques have been implemented, which benefit greatly from structured light methodologies. Such implementations facilitate the quantification and characterization of depth-resolved optical and physiological properties of thick and deep tissue at fast acquisition speeds. We summarize the current state of work and applications in the three main techniques leveraging structured light: spatial frequency-domain imaging, optical tomography, and single-pixel imaging. The theory, measurement, and analysis of spatial frequency-domain imaging are described. Then, advanced theories, processing, and imaging systems are summarized. Preclinical and clinical applications on physiological measurements for guidance and diagnosis are summarized. General theory and method development of tomographic approaches as well as applications including fluorescence molecular tomography are introduced. Lastly, recent developments of single-pixel imaging methodologies and applications are reviewed.
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Affiliation(s)
- Joseph P. Angelo
- National Institute of Standards and Technology, Sensor Science Division, Gaithersburg, Maryland, United States
- Address all correspondence to: Joseph P. Angelo, E-mail: ; Sez-Jade Chen, E-mail:
| | - Sez-Jade Chen
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
- Address all correspondence to: Joseph P. Angelo, E-mail: ; Sez-Jade Chen, E-mail:
| | - Marien Ochoa
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
| | - Ulas Sunar
- Wright State University, Department of Biomedical Industrial and Human Factor Engineering, Dayton, Ohio, United States
| | - Sylvain Gioux
- University of Strasbourg, ICube Laboratory, Strasbourg, France
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, Troy, New York, United States
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Near-Infrared Fluorescence-Enhanced Optical Tomography. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5040814. [PMID: 27803924 PMCID: PMC5075630 DOI: 10.1155/2016/5040814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/25/2016] [Indexed: 11/18/2022]
Abstract
Fluorescence-enhanced optical imaging using near-infrared (NIR) light developed for in vivo molecular targeting and reporting of cancer provides promising opportunities for diagnostic imaging. The current state of the art of NIR fluorescence-enhanced optical tomography is reviewed in the context of the principle of fluorescence, the different measurement schemes employed, and the mathematical tools established to tomographically reconstruct the fluorescence optical properties in various tissue domains. Finally, we discuss the recent advances in forward modeling and distributed memory parallel computation to provide robust, accurate, and fast fluorescence-enhanced optical tomography.
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Brůža P, Lin H, Vinogradov SA, Jarvis LA, Gladstone DJ, Pogue BW. Light sheet luminescence imaging with Cherenkov excitation in thick scattering media. OPTICS LETTERS 2016; 41:2986-9. [PMID: 27367082 DOI: 10.1364/ol.41.002986] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Light scattering leads to a severe loss of axial and transverse resolution with depth into tissue, limiting accuracy and value of biomedical luminescence imaging techniques. High-resolution imaging beyond a few-millimeter depth is prohibited because diffusive transport dominates beyond a few scattering distances. In this study, light sheet imaging through scattering media is demonstrated using a radiotherapy linear accelerator to deliver well-defined thin scanned sheets of x-rays. These sheets produce Cherenkov light within the medium, which in turn excites luminescence of an optical probe across the sheet plane. This luminescence can then be imaged by an intensified camera positioned perpendicular to the sheet plane. The precise knowledge of the light sheet position within the medium allowed for efficient attenuation correction of the signal with depth as well as spatial deconvolution of the excitation light. Together these methods allowed for the first time, to the best of our knowledge, high-resolution imaging of tissue-equivalent phantoms up to 3 cm thick, yielding the precise position and shape of luminescent lesions located deep in tissue without the need for nonlinear image reconstruction.
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Wang D, He J, Qiao H, Li P, Fan Y, Li D. Noncontact full-angle fluorescence molecular tomography system based on rotary mirrors. APPLIED OPTICS 2015; 54:7062-70. [PMID: 26368376 DOI: 10.1364/ao.54.007062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We propose a novel noncontact fluorescence molecular tomography system that achieves full-angle capacity with the use of a new rotary-mirrors-based imaging head. In the imaging head, four plane mirrors are mounted on a rotating gantry to enable illumination and detection over 360°. In comparison with existing full-angle systems, our system does not require rotation of the specimen animal, a large and heavy light source (with scanning head), or a bulky camera (with filters and lens). The system design and implementation are described in detail. Both physical phantom and in vivo experiments are performed to verify the performance of the proposed system.
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Yi X, Wang B, Wan W, Wang Y, Zhang Y, Zhao H, Gao F. Full time-resolved diffuse fluorescence tomography accelerated with parallelized Fourier-series truncated diffusion approximation. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:56003. [PMID: 25965088 DOI: 10.1117/1.jbo.20.5.056003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 04/17/2015] [Indexed: 06/04/2023]
Abstract
Of the three measurement schemes established for diffuse fluorescence tomography (DFT), the time-domain scheme is well known to provide the richest information about the distribution of the targeting fluorophore in living tissues. However, the explicit use of the full time-resolved data usually leads to a considerably lengthy time for image reconstruction, limiting its applications to three-dimensional or small-volume imaging. To cope with the adversity, we propose herein a computationally efficient scheme for DFT image reconstruction where the time-dependent photon density is expanded to a Fourier-series and calculated by solving the independent frequency-domain diffusion equations at multiple sampling frequencies with the support of a combined multicore CPU-based coarse-grain and multithread GPU-based fine-grain parallelization strategy. With such a parallelized Fourier-series truncated diffusion approximation, both the time- and frequency-domain inversion procedures are developed and validated for their effectiveness and accuracy using simulative and phantom experiments. The results show that the proposed method can generate reconstructions comparable to the explicit time-domain scheme, with significantly reduced computational time.
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Affiliation(s)
- Xi Yi
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, China
| | - Bingyuan Wang
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, China
| | - Wenbo Wan
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, China
| | - Yihan Wang
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, China
| | - Yanqi Zhang
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, China
| | - Huijuan Zhao
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, ChinabTianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin 300072, China
| | - Feng Gao
- Tianjin University, College of Precision Instrument and Optoelectronics Engineering, Weijinlu Avenue #92, Tianjin 300072, ChinabTianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin 300072, China
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Li B, Berti R, Abran M, Lesage F. Ultrasound guided fluorescence molecular tomography with improved quantification by an attenuation compensated Born-normalization and in vivo preclinical study of cancer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:053703. [PMID: 24880378 DOI: 10.1063/1.4875256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ultrasound imaging, having the advantages of low-cost and non-invasiveness over MRI and X-ray CT, was reported by several studies as an adequate complement to fluorescence molecular tomography with the perspective of improving localization and quantification of fluorescent molecular targets in vivo. Based on the previous work, an improved dual-modality Fluorescence-Ultrasound imaging system was developed and then validated in imaging study with preclinical tumor model. Ultrasound imaging and a profilometer were used to obtain the anatomical prior information and 3D surface, separately, to precisely extract the tissue boundary on both sides of sample in order to achieve improved fluorescence reconstruction. Furthermore, a pattern-based fluorescence reconstruction on the detection side was incorporated to enable dimensional reduction of the dataset while keeping the useful information for reconstruction. Due to its putative role in the current imaging geometry and the chosen reconstruction technique, we developed an attenuation compensated Born-normalization method to reduce the attenuation effects and cancel off experimental factors when collecting quantitative fluorescence datasets over large area. Results of both simulation and phantom study demonstrated that fluorescent targets could be recovered accurately and quantitatively using this reconstruction mechanism. Finally, in vivo experiment confirms that the imaging system associated with the proposed image reconstruction approach was able to extract both functional and anatomical information, thereby improving quantification and localization of molecular targets.
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Affiliation(s)
- Baoqiang Li
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7, Canada
| | - Romain Berti
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7, Canada
| | - Maxime Abran
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7, Canada
| | - Frédéric Lesage
- Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, Quebec H3C 3A7, Canada
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Hou SS, Rice WL, Bacskai BJ, Kumar ATN. Tomographic lifetime imaging using combined early- and late-arriving photons. OPTICS LETTERS 2014; 39:1165-8. [PMID: 24690697 PMCID: PMC4087160 DOI: 10.1364/ol.39.001165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We present a novel, hybrid approach for time domain fluorescence tomography that efficiently combines lifetime multiplexing using late-arriving or asymptotic photons, with the high spatial resolution capability of early photon tomography. We also show that a decay amplitude-based asymptotic approach is superior to direct inversion of late-arriving photons for tomographic lifetime imaging within turbid media. The hybrid reconstruction approach is experimentally shown to recover fluorescent inclusions separated as close as 1.4 mm, with improved resolution and reduced cross talk compared to just using early photons or the asymptotic approach alone.
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Affiliation(s)
- Steven S. Hou
- Alzheimer’s Disease Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - William L. Rice
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Brian J. Bacskai
- Alzheimer’s Disease Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Anand T. N. Kumar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Corresponding author:
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Ma G. Background-free in vivo time domain optical molecular imaging using colloidal quantum dots. ACS APPLIED MATERIALS & INTERFACES 2013; 5:2835-2844. [PMID: 23448359 DOI: 10.1021/am3028519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The interest in optical molecular imaging of small animals in vivo has been steadily increased in the last two decades as it is being adopted by not only academic laboratories but also the biotechnical and pharmaceutical industries. In this Spotlight paper, the elements for in vivo optical molecular imaging are briefly reviewed, including contrast agents, i.e., various fluorescent reporters, and the most commonly used technologies to detect the reporters. The challenges particularly for in vivo fluorescence imaging are discussed and solutions to overcome the said-challenges are presented. An advanced imaging technique, in vivo fluorescence lifetime imaging, is introduced together with a few application examples. Taking advantage of the long fluorescence lifetime of quantum dots, a method to achieve background-free in vivo fluorescence small animal imaging is demonstrated.
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Affiliation(s)
- Guobin Ma
- ART Advanced Research Technologies Inc., 2300 Alfred-Nobel Boulevard, Montreal, Quebec, Canada H4S 2A4.
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Ren S, Chen X, Wang H, Qu X, Wang G, Liang J, Tian J. Molecular Optical Simulation Environment (MOSE): a platform for the simulation of light propagation in turbid media. PLoS One 2013; 8:e61304. [PMID: 23577215 PMCID: PMC3620115 DOI: 10.1371/journal.pone.0061304] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/06/2013] [Indexed: 01/28/2023] Open
Abstract
The study of light propagation in turbid media has attracted extensive attention in the field of biomedical optical molecular imaging. In this paper, we present a software platform for the simulation of light propagation in turbid media named the “Molecular Optical Simulation Environment (MOSE)”. Based on the gold standard of the Monte Carlo method, MOSE simulates light propagation both in tissues with complicated structures and through free-space. In particular, MOSE synthesizes realistic data for bioluminescence tomography (BLT), fluorescence molecular tomography (FMT), and diffuse optical tomography (DOT). The user-friendly interface and powerful visualization tools facilitate data analysis and system evaluation. As a major measure for resource sharing and reproducible research, MOSE aims to provide freeware for research and educational institutions, which can be downloaded at http://www.mosetm.net.
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Affiliation(s)
- Shenghan Ren
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Xueli Chen
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Hailong Wang
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Xiaochao Qu
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
| | - Ge Wang
- Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- * E-mail: (GW); (JL); (JT)
| | - Jimin Liang
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
- * E-mail: (GW); (JL); (JT)
| | - Jie Tian
- School of Life Sciences and Technology, Xidian University, Xi’an, Shaanxi, China
- Institute of Automation, Chinese Academy of Sciences, Beijing, China
- * E-mail: (GW); (JL); (JT)
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Okawa S, Yano A, Uchida K, Mitsui Y, Yoshida M, Takekoshi M, Marjono A, Gao F, Hoshi Y, Kida I, Masamoto K, Yamada Y. Phantom and mouse experiments of time-domain fluorescence tomography using total light approach. BIOMEDICAL OPTICS EXPRESS 2013; 4:635-651. [PMID: 23577297 PMCID: PMC3617724 DOI: 10.1364/boe.4.000635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/12/2013] [Accepted: 02/14/2013] [Indexed: 06/02/2023]
Abstract
Phantom and mouse experiments of time-domain fluorescence tomography were conducted to demonstrate the total light approach which was previously proposed by authors. The total light approach reduces the computation time to solve the forward model for light propagation. Time-resolved temporal profiles were acquired for cylindrical phantoms having single or double targets containing indocyanine green (ICG) solutions. The reconstructed images of ICG concentration reflected the true distributions of ICG concentration with a spatial resolution of about 10 mm. In vivo experiments were conducted using a mouse in which an ICG capsule was embedded beneath the skin in the abdomen. The reconstructed image of the ICG concentration again reflected the true distribution of ICG although artifacts due to autofluorescence appeared in the vicinity of the skin. The effectiveness of the total light approach was demonstrated by the phantom and mouse experiments.
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Affiliation(s)
- Shinpei Okawa
- Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
- Currently with the Department of Medical Engineering, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Akira Yano
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Kazuki Uchida
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Yohei Mitsui
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Masaki Yoshida
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Masashi Takekoshi
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Andhi Marjono
- Graduate students of the Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Feng Gao
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Yoko Hoshi
- Integrated Neuroscience Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kami-kitazawa, Setagaya, Tokyo 156-8506, Japan
| | - Ikuhiro Kida
- Integrated Neuroscience Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kami-kitazawa, Setagaya, Tokyo 156-8506, Japan
| | - Kazuto Masamoto
- Center for Frontier Science and Engineering, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
| | - Yukio Yamada
- Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1 Chofuga-oka, Chofu, Tokyo 182-8585, Japan
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Venugopal V, Intes X. Adaptive wide-field optical tomography. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:036006. [PMID: 23475290 PMCID: PMC3591745 DOI: 10.1117/1.jbo.18.3.036006] [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: 11/17/2012] [Revised: 02/02/2013] [Accepted: 02/05/2013] [Indexed: 05/20/2023]
Abstract
We describe a wide-field optical tomography technique, which allows the measurement-guided optimization of illumination patterns for enhanced reconstruction performances. The iterative optimization of the excitation pattern aims at reducing the dynamic range in photons transmitted through biological tissue. It increases the number of measurements collected with high photon counts resulting in a dataset with improved tomographic information. Herein, this imaging technique is applied to time-resolved fluorescence molecular tomography for preclinical studies. First, the merit of this approach is tested by in silico studies in a synthetic small animal model for typical illumination patterns. Second, the applicability of this approach in tomographic imaging is validated in vitro using a small animal phantom with two fluorescent capillaries occluded by a highly absorbing inclusion. The simulation study demonstrates an improvement of signal transmitted (∼2 orders of magnitude) through the central portion of the small animal model for all patterns considered. A corresponding improvement in the signal at the emission wavelength by 1.6 orders of magnitude demonstrates the applicability of this technique for fluorescence molecular tomography. The successful discrimination and localization (∼1 mm error) of the two objects with higher resolution using the optimized patterns compared with nonoptimized illumination establishes the improvement in reconstruction performance when using this technique.
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Affiliation(s)
- Vivek Venugopal
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180
- Address all correspondence to: Xavier Intes, Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180. Tel: (518) 276-6964; E-mail:
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13
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In vivo tracking of murine adipose tissue-derived multipotent adult stem cells and ex vivo cross-validation. INTERNATIONAL JOURNAL OF MOLECULAR IMAGING 2013; 2013:426961. [PMID: 23401767 PMCID: PMC3562659 DOI: 10.1155/2013/426961] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/23/2012] [Indexed: 01/13/2023]
Abstract
Stem cells are characterized by the ability to renew themselves and to differentiate into specialized cell types, while stem cell therapy is believed to treat a number of different human diseases through either cell regeneration or paracrine effects. Herein, an in vivo and ex vivo near infrared time domain (NIR TD) optical imaging study was undertaken to evaluate the migratory ability of murine adipose tissue-derived multipotent adult stem cells [mAT-MASC] after intramuscular injection in mice. In vivo NIR TD optical imaging data analysis showed a migration of DiD-labelled mAT-MASC in the leg opposite the injection site, which was confirmed by a fibered confocal microendoscopy system. Ex vivo NIR TD optical imaging results showed a systemic distribution of labelled cells. Considering a potential microenvironmental contamination, a cross-validation study by multimodality approaches was followed: mAT-MASC were isolated from male mice expressing constitutively eGFP, which was detectable using techniques of immunofluorescence and qPCR. Y-chromosome positive cells, injected into wild-type female recipients, were detected by FISH. Cross-validation confirmed the data obtained by in vivo/ex vivo TD optical imaging analysis. In summary, our data demonstrates the usefulness of NIR TD optical imaging in tracking delivered cells, giving insights into the migratory properties of the injected cells.
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Ex vivo fluorescence molecular tomography of the spine. Int J Biomed Imaging 2012; 2012:942326. [PMID: 23197973 PMCID: PMC3503328 DOI: 10.1155/2012/942326] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/26/2012] [Indexed: 11/17/2022] Open
Abstract
We investigated the potential of fluorescence molecular tomography to image ex vivo samples collected from a large animal model, in this case, a dog spine. Wide-field time-gated fluorescence tomography was employed to assess the impact of multiview acquisition, data type, and intrinsic optical properties on the localization and quantification accuracy in imaging a fluorescent inclusion in the intervertebral disk. As expected, the TG data sets, when combining early and late gates, provide significantly better performances than the CW data sets in terms of localization and quantification. Moreover, the use of multiview imaging protocols led to more accurate localization. Additionally, the incorporation of the heterogeneous nature of the tissue in the model to compute the Jacobians led to improved imaging performances. This preliminary imaging study provides a proof of concept of the feasibility of quantitatively imaging complex ex vivo samples nondestructively and with short acquisition times. This work is the first step towards employing optical molecular imaging of the spine to detect and characterize disc degeneration based on targeted fluorescent probes.
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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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16
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Zhu Q, Dehghani H, Tichauer KM, Holt RW, Vishwanath K, Leblond F, Pogue BW. A three-dimensional finite element model and image reconstruction algorithm for time-domain fluorescence imaging in highly scattering media. Phys Med Biol 2011; 56:7419-34. [PMID: 22056913 DOI: 10.1088/0031-9155/56/23/006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this work, development and evaluation of a three-dimensional (3D) finite element model (FEM) based on the diffusion approximation of time-domain (TD) near-infrared fluorescence light transport in biological tissue is presented. This model allows both excitation and fluorescence temporal point-spread function (TPSF) data to be generated for heterogeneous scattering and absorbing media of arbitrary geometry. The TD FEM is evaluated via comparisons with analytical and Monte Carlo (MC) calculations and is shown to provide a quantitative accuracy which has less than 0.72% error in intensity and less than 37 ps error for mean time. The use of the Born-Ratio normalized data is demonstrated to reduce data mismatch between MC and FEM to less than 0.22% for intensity and less than 22 ps in mean time. An image reconstruction framework, based on a 3D FEM formulation, is outlined and simulation results based on a heterogeneous mouse model with a source of fluorescence in the pancreas is presented. It is shown that using early photons (i.e. the photons detected within the first 200 ps of the TPSF) improves the spatial resolution compared to using continuous-wave signals. It is also demonstrated, as expected, that the utilization of two time gates (early and latest photons) can improve the accuracy both in terms of spatial resolution and recovered contrast.
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Affiliation(s)
- Q Zhu
- School of Computer Science, University of Birmingham, Birmingham, B15 2TT, UK
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17
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Abstract
Abstract
In vitro studies have documented β2 glycoprotein I (β2GPI) binding to endothelial cells (ECs) and trophoblast using antiphospholipid antibodies. The in vivo binding of β2GPI to these cells and the conditions that favor their interaction have not been investigated. We analyzed the in vivo distribution of cyanine 5.5-labeled β2GPI in mice and evaluated the effect of pregnancy and circulating antibodies on its tissue localization. The signal was detected in the liver by whole body scan and ex vivo analysis. The β2GPI failed to bind to the vascular endothelium and reacted only with the ECs of uterine vessels. In pregnant mice the protein was localized on ECs and trophoblast at the embryo implantation sites. Immunized mice showed a similar β2GPI biodistribution to naive mice but the immunized pregnant animals exhibited a significant increase in fetal loss associated with C3 and C9 deposition at the implantation sites. Treatment of mice with LPS after β2GPI-Cy5.5 injection promoted protein localization on gut and brain ECs associated with IgG, C1q, and C9 deposition in immunized mice. These findings indicate that β2GPI binding to EC requires priming with pro-inflammatory factors which is not needed for uterine and placental localization probably dependent on hormonal changes.
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18
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Ducros N, D’Andrea C, Bassi A, Peyrin F. Fluorescence diffuse optical tomography: Time-resolved versus continuous-wave in the reflectance configuration. Ing Rech Biomed 2011. [DOI: 10.1016/j.irbm.2011.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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19
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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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20
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Larusson F, Fantini S, Miller EL. Hyperspectral image reconstruction for diffuse optical tomography. BIOMEDICAL OPTICS EXPRESS 2011; 2:946-65. [PMID: 21483616 PMCID: PMC3072133 DOI: 10.1364/boe.2.000946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/10/2011] [Accepted: 03/10/2011] [Indexed: 05/25/2023]
Abstract
We explore the development and performance of algorithms for hyperspectral diffuse optical tomography (DOT) for which data from hundreds of wavelengths are collected and used to determine the concentration distribution of chromophores in the medium under investigation. An efficient method is detailed for forming the images using iterative algorithms applied to a linearized Born approximation model assuming the scattering coefficient is spatially constant and known. The L-surface framework is employed to select optimal regularization parameters for the inverse problem. We report image reconstructions using 126 wavelengths with estimation error in simulations as low as 0.05 and mean square error of experimental data of 0.18 and 0.29 for ink and dye concentrations, respectively, an improvement over reconstructions using fewer specifically chosen wavelengths.
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Affiliation(s)
- Fridrik Larusson
- Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155,
USA
| | - Sergio Fantini
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155,
USA
| | - Eric L. Miller
- Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155,
USA
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21
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Chen J, Venugopal V, Intes X. Monte Carlo based method for fluorescence tomographic imaging with lifetime multiplexing using time gates. BIOMEDICAL OPTICS EXPRESS 2011; 2:871-86. [PMID: 21483610 PMCID: PMC3072127 DOI: 10.1364/boe.2.000871] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 02/25/2011] [Accepted: 02/26/2011] [Indexed: 05/04/2023]
Abstract
Time-resolved fluorescence optical tomography allows 3-dimensional localization of multiple fluorophores based on lifetime contrast while providing a unique data set for improved resolution. However, to employ the full fluorescence time measurements, a light propagation model that accurately simulates weakly diffused and multiple scattered photons is required. In this article, we derive a computationally efficient Monte Carlo based method to compute time-gated fluorescence Jacobians for the simultaneous imaging of two fluorophores with lifetime contrast. The Monte Carlo based formulation is validated on a synthetic murine model simulating the uptake in the kidneys of two distinct fluorophores with lifetime contrast. Experimentally, the method is validated using capillaries filled with 2.5nmol of ICG and IRDye™800CW respectively embedded in a diffuse media mimicking the average optical properties of mice. Combining multiple time gates in one inverse problem allows the simultaneous reconstruction of multiple fluorophores with increased resolution and minimal crosstalk using the proposed formulation.
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Affiliation(s)
- Jin Chen
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Vivek Venugopal
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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22
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Li M, Zhang Y, Bai J. In Vivo Diffuse Optical Tomography and Fluorescence Molecular Tomography. JOURNAL OF HEALTHCARE ENGINEERING 2010. [DOI: 10.1260/2040-2295.1.3.477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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23
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Davis SC, Samkoe KS, O'Hara JA, Gibbs-Strauss SL, Paulsen KD, Pogue BW. Comparing implementations of magnetic-resonance-guided fluorescence molecular tomography for diagnostic classification of brain tumors. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:051602. [PMID: 21054076 PMCID: PMC2951993 DOI: 10.1117/1.3483902] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 05/10/2010] [Accepted: 05/17/2010] [Indexed: 05/25/2023]
Abstract
Fluorescence molecular tomography (FMT) systems coupled to conventional imaging modalities such as magnetic resonance imaging (MRI) and computed tomography provide unique opportunities to combine data sets and improve image quality and content. Yet, the ideal approach to combine these complementary data is still not obvious. This preclinical study compares several methods for incorporating MRI spatial prior information into FMT imaging algorithms in the context of in vivo tissue diagnosis. Populations of mice inoculated with brain tumors that expressed either high or low levels of epidermal growth factor receptor (EGFR) were imaged using an EGF-bound near-infrared dye and a spectrometer-based MRI-FMT scanner. All data were spectrally unmixed to extract the dye fluorescence from the tissue autofluorescence. Methods to combine the two data sets were compared using student's t-tests and receiver operating characteristic analysis. Bulk fluorescence measurements that made up the optical imaging data set were also considered in the comparison. While most techniques were able to distinguish EGFR(+) tumors from EGFR(-) tumors and control animals, with area-under-the-curve values=1, only a handful were able to distinguish EGFR(-) tumors from controls. Bulk fluorescence spectroscopy techniques performed as well as most imaging techniques, suggesting that complex imaging algorithms may be unnecessary to diagnose EGFR status in these tissue volumes.
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Affiliation(s)
- Scott C Davis
- Dartmouth College, Thayer School of Engineering, HB 8000, Hanover, New Hampshire 03755, USA.
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24
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Raymond SB, Boas DA, Bacskai BJ, Kumar ATN. Lifetime-based tomographic multiplexing. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:046011. [PMID: 20799813 PMCID: PMC2929260 DOI: 10.1117/1.3469797] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Revised: 05/16/2010] [Accepted: 06/01/2010] [Indexed: 05/18/2023]
Abstract
Near-infrared (NIR) fluorescence tomography of multiple fluorophores has previously been limited by the bandwidth of the NIR spectral regime and the broad emission spectra of most NIR fluorophores. We describe in vivo tomography of three spectrally overlapping fluorophores using fluorescence lifetime-based separation. Time-domain images are acquired using a voltage-gated, intensified charge-coupled device (CCD) in free-space transmission geometry with 750 nm Ti:sapphire laser excitation. Lifetime components are fit from the asymptotic portion of fluorescence decay curve and reconstructed separately with a lifetime-adjusted forward model. We use this system to test the in vivo lifetime multiplexing suitability of commercially available fluorophores, and demonstrate lifetime multiplexing in solution mixtures and in nude mice. All of the fluorophores tested exhibit nearly monoexponential decays, with narrow in vivo lifetime distributions suitable for lifetime multiplexing. Quantitative separation of two fluorophores with lifetimes of 1.1 and 1.37 ns is demonstrated for relative concentrations of 1:5. Finally, we demonstrate tomographic imaging of two and three fluorophores in nude mice with fluorophores that localize to distinct organ systems. This technique should be widely applicable to imaging multiple NIR fluorophores in 3-D.
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Affiliation(s)
- Scott B Raymond
- The Harvard-MIT Division of Health Sciences and Technology, Charlestown, Massachusetts 02129, USA
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25
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Gao F, Li J, Zhang L, Poulet P, Zhao H, Yamada Y. Simultaneous fluorescence yield and lifetime tomography from time-resolved transmittances of small-animal-sized phantom. APPLIED OPTICS 2010; 49:3163-72. [PMID: 20517387 DOI: 10.1364/ao.49.003163] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
There has been recently a considerable interest in simultaneously reconstructing yield and lifetime distributions of fluorescent imaging agents inside a bulky tissue, since combined monitoring of these two parameters provides a potential means of in vivo interrogating quantitative and environmental information of specific molecules, as well as accessing interactions among them. It is widely accepted that an advantageous way of accomplishing the task in the context of small-animal imaging is to use a time-domain (TD) modality. In this paper, we present a full three-dimensional, featured-data algorithm for TD diffuse fluorescence tomography, which inverts the Laplace-transformed TD coupled photon diffusion equations and employs a pair of real-domain transform-factors to effectively separate the fluorescent yield and lifetime parameters. By use of a specifically designed 16x16 channel time-correlated single photon counting system and a normalized Born formulation for the inversion, the proposed scheme in a transmission mode is experimentally validated to achieve simultaneous reconstruction of the fluorescent yield and lifetime distributions with reasonable accuracy.
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Affiliation(s)
- Feng Gao
- College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China.
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26
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Ducros N, Da Silva A, Dinten JM, Seelamantula CS, Unser M, Peyrin F. A time-domain wavelet-based approach for fluorescence diffuse optical tomography. Med Phys 2010; 37:2890-900. [DOI: 10.1118/1.3431571] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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27
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de la Zerda A, Bodapati S, Teed R, Schipper ML, Keren S, Smith BR, Ng JST, Gambhir SS. A comparison between time domain and spectral imaging systems for imaging quantum dots in small living animals. Mol Imaging Biol 2009; 12:500-8. [PMID: 20012220 DOI: 10.1007/s11307-009-0290-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 07/06/2009] [Accepted: 07/29/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE We quantified the performance of time-domain imaging (TDI) and spectral imaging (SI) for fluorescence imaging of quantum dots (QDs) in three distinct imaging instruments: eXplore Optix (TDI, Advanced Research Technologies Inc.), Maestro (SI, CRi Inc.), and IVIS-Spectrum (SI, Caliper Life Sciences Inc.). PROCEDURE The instruments were compared for their sensitivity in phantoms and living mice, multiplexing capabilities (ability to resolve the signal of one QD type in the presence of another), and the dependence of contrast and spatial resolution as a function of depth. RESULTS In phantoms, eXplore Optix had an order of magnitude better sensitivity compared to the SI systems, detecting QD concentrations of ~40 pM in vitro. Maestro was the best instrument for multiplexing QDs. Reduction of contrast and resolution as a function of depth was smallest with eXplore Optix for depth of 2-6 mm, while other depths gave comparable results in all systems. Sensitivity experiments in living mice showed that the eXplore Optix and Maestro systems outperformed the IVIS-Spectrum. CONCLUSION TDI was found to be an order of magnitude more sensitive than SI at the expense of speed and very limited multiplexing capabilities. For deep tissue QD imaging, TDI is most applicable for depths between 2 and 6 mm, as its contrast and resolution degrade the least at these depths.
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Affiliation(s)
- Adam de la Zerda
- Department of Radiology, Molecular Imaging Program at Stanford (MIPS), The Bio-X Program, Stanford, CA 94305, USA
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28
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Leblond F, Davis SC, Valdés PA, Pogue BW. Pre-clinical whole-body fluorescence imaging: Review of instruments, methods and applications. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 98:77-94. [PMID: 20031443 DOI: 10.1016/j.jphotobiol.2009.11.007] [Citation(s) in RCA: 358] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 11/16/2009] [Accepted: 11/20/2009] [Indexed: 01/07/2023]
Abstract
Fluorescence sampling of cellular function is widely used in all aspects of biology, allowing the visualization of cellular and sub-cellular biological processes with spatial resolutions in the range from nanometers up to centimeters. Imaging of fluorescence in vivo has become the most commonly used radiological tool in all pre-clinical work. In the last decade, full-body pre-clinical imaging systems have emerged with a wide range of utilities and niche application areas. The range of fluorescent probes that can be excited in the visible to near-infrared part of the electromagnetic spectrum continues to expand, with the most value for in vivo use being beyond the 630 nm wavelength, because the absorption of light sharply decreases. Whole-body in vivo fluorescence imaging has not yet reached a state of maturity that allows its routine use in the scope of large-scale pre-clinical studies. This is in part due to an incomplete understanding of what the actual fundamental capabilities and limitations of this imaging modality are. However, progress is continuously being made in research laboratories pushing the limits of the approach to consistently improve its performance in terms of spatial resolution, sensitivity and quantification. This paper reviews this imaging technology with a particular emphasis on its potential uses and limitations, the required instrumentation, and the possible imaging geometries and applications. A detailed account of the main commercially available systems is provided as well as some perspective relating to the future of the technology development. Although the vast majority of applications of in vivo small animal imaging are based on epi-illumination planar imaging, the future success of the method relies heavily on the design of novel imaging systems based on state-of-the-art optical technology used in conjunction with high spatial resolution structural modalities such as MRI, CT or ultrasound.
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Affiliation(s)
- Frederic Leblond
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
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29
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Ducros N, Da Silva A, Hervé L, Dinten JM, Peyrin F. A comprehensive study of the use of temporal moments in time-resolved diffuse optical tomography: part II. Three-dimensional reconstructions. Phys Med Biol 2009; 54:7107-19. [DOI: 10.1088/0031-9155/54/23/005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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30
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Ducros N, Hervé L, Da Silva A, Dinten JM, Peyrin F. A comprehensive study of the use of temporal moments in time-resolved diffuse optical tomography: part I. Theoretical material. Phys Med Biol 2009; 54:7089-105. [DOI: 10.1088/0031-9155/54/23/004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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31
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Chen J, Intes X. Time-gated perturbation Monte Carlo for whole body functional imaging in small animals. OPTICS EXPRESS 2009; 17:19566-79. [PMID: 19997176 PMCID: PMC4640470 DOI: 10.1364/oe.17.019566] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This paper explores a time-resolved functional imaging method based on Monte Carlo model for whole-body functional imaging of small animals. To improve the spatial resolution and quantitative accuracy of the functional map, a Bayesian hierarchical method with a high resolution spatial prior is applied to guide the optical reconstructions. Simulated data using the proposed approach are employed on an anatomically accurate mouse model where the optical properties range and volume limitations of the diffusion equation model exist. We investigate the performances of using time-gated data type and spatial priors to quantitatively image the functional parameters of multiple organs. Accurate reconstructions of the two main functional parameters of the blood volume and the relative oxygenation are demonstrated by using our method. Moreover, nonlinear optode settings guided by anatomical prior is proved to be critical to imaging small organs such as the heart.
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32
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Leblond F, Dehghani H, Kepshire D, Pogue BW. Early-photon fluorescence tomography: spatial resolution improvements and noise stability considerations. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2009; 26:1444-57. [PMID: 19488184 PMCID: PMC3801162 DOI: 10.1364/josaa.26.001444] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In vivo tissue imaging using near-infrared light suffers from low spatial resolution and poor contrast recovery because of highly scattered photon transport. For diffuse optical tomography (DOT) and fluorescence molecular tomography (FMT), the resolution is limited to about 5-10% of the diameter of the tissue being imaged, which puts it in the range of performance seen in nuclear medicine. This paper introduces the mathematical formalism explaining why the resolution of FMT can be significantly improved when using instruments acquiring fast time-domain optical signals. This is achieved through singular-value analysis of the time-gated inverse problem based on weakly diffused photons. Simulations relevant to mouse imaging are presented showing that, in stark contrast to steady-state imaging, early time-gated intensities (within 200 ps or 400 ps) can in principle be used to resolve small fluorescent targets (radii from 1.5 to 2.5 mm) separated by less than 1.5 mm.
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Affiliation(s)
- Frederic Leblond
- Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover New Hampshire 03755, USA.
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33
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Alvarez D, Medina P, Moscoso M. Fluorescence lifetime imaging from time resolved measurements using a shape-based approach. OPTICS EXPRESS 2009; 17:8843-8855. [PMID: 19466134 DOI: 10.1364/oe.17.008843] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a novel fluorescent tomography algorithm to estimate the spatial distribution of fluorophores and the fluorescence lifetimes from surface time resolved measurements. The algorithm is a hybridization of the level set technique for recovering the distributions of distinct fluorescent markers with a gradient method for estimating their lifetimes. This imaging method offers several advantages compared to more traditional pixel-based techniques as, for example, well defined boundaries and a better resolution of the images. The numerical experiments show that our imaging method gives rise to accurate reconstructions in the presence of data noise and fluorescence background even for complicated fluorophore distributions in several-centimiter-thick biological tissue.
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Affiliation(s)
- Diego Alvarez
- Gregorio Millán Institute, Universidad Carlos III de Madrid, Avda. de Universidad 30, 28911 Leganés, Spain. jdiego,pmedina,
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Biffi S, Garrovo C, Macor P, Tripodo C, Zorzet S, Secco E, Tedesco F, Lorusso V. In Vivo Biodistribution and Lifetime Analysis of Cy5.5-Conjugated Rituximab in Mice Bearing Lymphoid Tumor Xenograft Using Time-Domain Near-Infrared Optical Imaging. Mol Imaging 2008. [DOI: 10.2310/7290.2008.00028] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rituximab is a chimeric monoclonal antibody directed against human CD20 antigen, which is expressed on B-cell lymphocytes and on the majority of B-cell lymphoid malignancies. Herein we report the conjugate of rituximab with the near-infrared (NIR) fluorophore Cy5.5 (RI-Cy5.5) as a tool for in vitro, in vivo, and ex vivo NIR time-domain (TD) optical imaging. In vitro, RI-Cy5.5 retained biologic activity and led to elevated cell-associated fluorescence on tumor cells. In vivo, TD optical imaging analysis of RI-Cy5.5 injected into lymphoma-bearing mice revealed a slow tumor uptake and a specific long-lasting persistence of the probe within the tumor. Biodistribution studies after intraperitoneal and endovenous administration were undertaken to evaluate differences in the tumor uptake. RI-Cy5.5 concentration in the organs after intraperitoneal injection was not as high as after endovenous injection. Ex vivo analysis of biologic tissues and organs by both TD optical imaging and immunohistochemistry confirmed the probe distribution, as demonstrated by imaging experiment in vivo, showing that RI-Cy5.5 selectively accumulated in the tumor tissue and major excretion organs. In summary, the study indicates that NIR TD optical imaging is a powerful tool for rituximab-targeting investigation, furthering understanding of its administration outcome in lymphoma treatment.
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Affiliation(s)
- Stefania Biffi
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Chiara Garrovo
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Paolo Macor
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Claudio Tripodo
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Sonia Zorzet
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Erika Secco
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Francesco Tedesco
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
| | - Vito Lorusso
- From the Optical Imaging Laboratory, CBM, Area Science Park, Trieste, Italy; Department of Life Sciences, University of Trieste, Trieste, Italy; Department of Human Pathology, University of Palermo, Palermo, Italy; and Bracco Research Centre, Bracco Imaging S.p.a., Colleretto Giacosa, Torino, Italy
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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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36
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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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37
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Gao F, Zhao H, Zhang L, Tanikawa Y, Marjono A, Yamada Y. A self-normalized, full time-resolved method for fluorescence diffuse optical tomography. OPTICS EXPRESS 2008; 16:13104-13121. [PMID: 18711549 DOI: 10.1364/oe.16.013104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A full time-resolved scheme that has been previously applied in diffuse optical tomography is extended to time-domain fluorescence diffuse optical tomography regime, based on a finite-element-finite-time-difference photon diffusion modeling and a Newton-Raphson inversion framework. The merits of using full time-resolved data are twofold: it helps evaluate the intrinsic performance of time-domain mode for improvement of image quality and set up a valuable reference to the assessment of computationally efficient featured-data-based algorithms, and provides a self-normalized implementation to preclude the necessity of the scaling-factor calibration and spectroscopic-feature assessments of the system as well as to overcome the adversity of system instability. We validate the proposed methodology using simulated data, and evaluate its performances of simultaneous recovery of the fluorescent yield and lifetime as well as its superiority to the featured-data one in the fidelity of image reconstruction.
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Affiliation(s)
- Feng Gao
- College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tianjin 300072, China.
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38
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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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39
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Janunts E, Pöschinger T, Brünner H, Langenbucher A. Linear method of fluorescent source reconstruction in a diffusion medium. Z Med Phys 2008; 18:189-96. [DOI: 10.1016/j.zemedi.2008.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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40
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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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41
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Zhang L, Gao F, He H, Zhao H. Three-dimensional scheme for time-domain fluorescence molecular tomography based on Laplace transforms with noise-robust factors. OPTICS EXPRESS 2008; 16:7214-23. [PMID: 18545426 DOI: 10.1364/oe.16.007214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
As a visualizing and quantitative method, Fluorescence Molecular Tomography (FMT) has many potential applications in biomedical field and its three-dimensional (3D) implementation is needed in both theory and practice. In this paper, we propose a 3D scheme for time-domain FMT within the normalized Born-ratio formulation. A finite element method solution to the Laplace transformed time-domain coupled diffusion equations is employed as the forward model, and the resultant linear inversions at two distinct transform-factors are solved with an algebraic reconstruction technique to separate fluorescent yield and lifetime images. The algorithm is validated using simulated data for 3D cylinder phantoms, and the spatial resolution and quantitativeness of the reconstruction assessed. We demonstrate that the proposed approach can accurately retrieve the positions and shapes of the targets with high spatial resolution and quantitative accuracy, and tolerate a signal-to-noise ratio down to 25dB by appropriately choosing the transform factors.
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Affiliation(s)
- Limin Zhang
- College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tianjin 300072, China.
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42
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Keren S, Gheysens O, Levin CS, Gambhir SS. A comparison between a time domain and continuous wave small animal optical imaging system. IEEE TRANSACTIONS ON MEDICAL IMAGING 2008; 27:58-63. [PMID: 18270062 PMCID: PMC4143158 DOI: 10.1109/tmi.2007.902800] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a phantom study to evaluate the performance of the eXplore Optix (Advanced Research Technologies-GE Healthcare), the first commercially available time-domain tomography system for small animal fluorescence imaging, and compare its capabilities with the widely used IVIS 200 (Xenogen Corporation-Caliper) continuous wave planar imaging system. The eXplore Optix, based on point-wise illumination and collection scheme, is found to be a log order more sensitive with significantly higher detection depth and spatial resolution as compared with the wide-area illumination IVIS 200 under the conditions tested. A time-resolved detection system allows the eXplore Optix to measure the arrival time distribution of fluorescence photons. This enables fluorescence lifetime measurement, absorption mapping, and estimation of fluorescent inclusion depth, which in turn is used by a reconstruction algorithm to calculate the volumetric distribution of the fluorophore concentration. An increased acquisition time and lack of ability to image multiple animals simultaneously are the main drawbacks of the eXplore Optix as compared with the IVIS 200.
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Affiliation(s)
- Shay Keren
- Molecular Imaging Program at Stanford (MIPS), Radiology Department, Stanford University, Stanford, CA 94305 USA
| | - Olivier Gheysens
- Molecular Imaging Program at Stanford (MIPS), Radiology Department, Stanford University, Stanford, CA 94305 USA
| | - Craig S. Levin
- Molecular Imaging Program at Stanford (MIPS), Radiology Department, Stanford University, Stanford, CA 94305 USA
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43
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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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44
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Soloviev VY, Tahir KB, McGinty J, Elson DS, Neil MAA, French PMW, Arridge SR. Fluorescence lifetime imaging by using time-gated data acquisition. APPLIED OPTICS 2007; 46:7384-91. [PMID: 17952172 DOI: 10.1364/ao.46.007384] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The use of the time gating technique for lifetime reconstruction in the Fourier domain is a novel technique. Time gating provides sufficient data points in the time domain for reliable application of the Fourier transform, which is essential for the time deconvolution of the system of the integral equations employed in the reconstruction. The Fourier domain telegraph equation is employed to model the light transport, which allows a sufficiently broad interval of frequencies to be covered. Reconstructed images contain enough information needed for recovering the lifetime distribution in a sample for any given frequency within the megahertz-gigahertz band. The use of this technique is essential for recovering time-dependent information in fluorescence imaging. This technique was applied in reconstruction of the lifetime distribution of four tubes filled with Rhodamine 6G embedded inside a highly scattering slab. Relatively accurate fluorescence lifetime reconstruction demonstrates the effectiveness and the potential of the proposed technique.
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45
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Abulrob A, Brunette E, Slinn J, Baumann E, Stanimirovic D. In Vivo Time Domain Optical Imaging of Renal Ischemia-Reperfusion Injury: Discrimination Based on Fluorescence Lifetime. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Fluorescence lifetime is an intrinsic parameter of the fluorescent probe, independent of the probe concentration but sensitive to changes in the surrounding microenvironment. Therefore, fluorescence lifetime imaging could potentially be applied to in vivo diagnostic assessment of changes in the tissue microenvironment caused by disease, such as ischemia. The aim of this study was to evaluate the utility of noninvasive fluorescence lifetime imaging in distinguishing between normal and ischemic kidney tissue in vivo. Mice were subjected to 60-minute unilateral kidney ischemia followed by 6-hour reperfusion. Animals were then injected with the near-infrared fluorescence probe Cy5.5 or saline and imaged using a time-domain small-animal optical imaging system. Both fluorescence intensity and lifetime were acquired. The fluorescence intensity of Cy5.5 was clearly reduced in the ischemic compared with the contralateral kidney, and the fluorescence lifetime of Cy5.5 was not detected in the ischemic kidney, suggesting reduced kidney clearance. Interestingly, the two-component lifetime analysis of endogenous fluorescence at 700 nm distinguished renal ischemia in vivo without the need for Cy5.5 injection for contrast enhancement. The average fluorescence lifetime of endogenous tissue fluorophores was a sensitive indicator of kidney ischemia ex vivo. The study suggests that fluorescence lifetime analysis of endogenous tissue fluorophores could be used to discriminate ischemic or necrotic tissues by noninvasive in vivo or ex vivo organ imaging.
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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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46
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Akers W, Lesage F, Holten D, Achilefu S. In Vivo Resolution of Multiexponential Decays of Multiple Near-Infrared Molecular Probes by Fluorescence Lifetime-Gated Whole-Body Time-Resolved Diffuse Optical Imaging. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The biodistribution of two near-infrared fluorescent agents was assessed in vivo by time-resolved diffuse optical imaging. Bacteriochlorophyll a (BC) and cypate-glysine-arginine-aspartic acid-serine-proline-lysine-OH (Cyp-GRD) were administered separately or combined to mice with subcutaneous xenografts of human breast adenocarcinoma and slow-release estradiol pellets for improved tumor growth. The same excitation (780 nm) and emission (830 nm) wavelengths were used to image the distinct fluorescence lifetime distribution of the fluorescent molecular probes in the mouse cancer model. Fluorescence intensity and lifetime maps were reconstructed after raster-scanning whole-body regions of interest by time-correlated single-photon counting. Each captured temporal point-spread function (TPSF) was deconvolved using both a single and a multiexponental decay model to best determine the measured fluorescence lifetimes. The relative signal from each fluorophore was estimated for any region of interest included in the scanned area. Deconvolution of the individual TPSFs from whole-body fluorescence intensity scans provided corresponding lifetime images for comparing individual component biodistribution. In vivo fluorescence lifetimes were determined to be 0.8 ns (Cyp-GRD) and 2 ns (BC). This study demonstrates that the relative biodistribution of individual fluorophores with similar spectral characteristics can be compartmentalized by using the time-domain fluorescence lifetime gating method.
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Affiliation(s)
- Walter Akers
- From the Optical Radiology Lab, Department of Radiology, and Department of Chemistry, Washington University School of Medicine, St. Louis, MO; and the Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC
| | - Frederic Lesage
- From the Optical Radiology Lab, Department of Radiology, and Department of Chemistry, Washington University School of Medicine, St. Louis, MO; and the Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC
| | - Dewey Holten
- From the Optical Radiology Lab, Department of Radiology, and Department of Chemistry, Washington University School of Medicine, St. Louis, MO; and the Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC
| | - Samuel Achilefu
- From the Optical Radiology Lab, Department of Radiology, and Department of Chemistry, Washington University School of Medicine, St. Louis, MO; and the Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, QC
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47
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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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48
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Ducros N, Da Silva A, Dinten JM, Peyrin F. A simulation-based study of reconstruction in time-resolved fluorescence diffuse optical tomography in cylindrical geometry. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2007; 2007:2639-2642. [PMID: 18002537 DOI: 10.1109/iembs.2007.4352871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The present paper is devoted to fluorescence diffuse optical tomography by using time resolved signals for the reconstruction of the 3D biodistribution of fluorescent probes embedded in biological tissues. The focus is made on the reconstruction of a methodology for an efficient exploitation of the time resolved data. The study is restricted to the examination of the three first moments of signals acquired in cylindrical geometry. The interest of temporal information upon CW information has been shown especially when only a limited number of views is available.
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Affiliation(s)
- Nicolas Ducros
- Micro Technologies for Biology and Healthcare Division, CEA-LETI MINATEC, 17 rue des Martyrs, 38054 Grenoble, France.
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