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Vega JD, Hara D, Schmidt RM, Abuhaija MB, Tao W, Dogan N, Pollack A, Ford JC, Shi J. In vivo active-targeting fluorescence molecular imaging with adaptive background fluorescence subtraction. Front Oncol 2023; 13:1130155. [PMID: 36998445 PMCID: PMC10043309 DOI: 10.3389/fonc.2023.1130155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/28/2023] [Indexed: 03/18/2023] Open
Abstract
Using active tumor-targeting nanoparticles, fluorescence imaging can provide highly sensitive and specific tumor detection, and precisely guide radiation in translational radiotherapy study. However, the inevitable presence of non-specific nanoparticle uptake throughout the body can result in high levels of heterogeneous background fluorescence, which limits the detection sensitivity of fluorescence imaging and further complicates the early detection of small cancers. In this study, background fluorescence emanating from the baseline fluorophores was estimated from the distribution of excitation light transmitting through tissues, by using linear mean square error estimation. An adaptive masked-based background subtraction strategy was then implemented to selectively refine the background fluorescence subtraction. First, an in vivo experiment was performed on a mouse intratumorally injected with passively targeted fluorescent nanoparticles, to validate the reliability and robustness of the proposed method in a stringent situation wherein the target fluorescence was overlapped with the strong background. Then, we conducted in vivo studies on 10 mice which were inoculated with orthotopic breast tumors and intravenously injected with actively targeted fluorescent nanoparticles. Results demonstrated that active targeting combined with the proposed background subtraction method synergistically increased the accuracy of fluorescence molecular imaging, affording sensitive tumor detection.
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Affiliation(s)
- Jorge D. Vega
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Daiki Hara
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Ryder M. Schmidt
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Marwan B. Abuhaija
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Wensi Tao
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Nesrin Dogan
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Alan Pollack
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - John C. Ford
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
- *Correspondence: John C. Ford, ; Junwei Shi,
| | - Junwei Shi
- Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, United States
- *Correspondence: John C. Ford, ; Junwei Shi,
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2
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Ochoa M, Rudkouskaya A, Smith JT, Intes X, Barroso M. Macroscopic Fluorescence Lifetime Imaging for Monitoring of Drug-Target Engagement. Methods Mol Biol 2022; 2394:837-856. [PMID: 35094361 PMCID: PMC8941982 DOI: 10.1007/978-1-0716-1811-0_44] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Precision medicine promises to improve therapeutic efficacy while reducing adverse effects, especially in oncology. However, despite great progresses in recent years, precision medicine for cancer treatment is not always part of routine care. Indeed, the ability to specifically tailor therapies to distinct patient profiles requires still significant improvements in targeted therapy development as well as decreases in drug treatment failures. In this regard, preclinical animal research is fundamental to advance our understanding of tumor biology, and diagnostic and therapeutic response. Most importantly, the ability to measure drug-target engagement accurately in live and intact animals is critical in guiding the development and optimization of targeted therapy. However, a major limitation of preclinical molecular imaging modalities is their lack of capability to directly and quantitatively discriminate between drug accumulation and drug-target engagement at the pathological site. Recently, we have developed Macroscopic Fluorescence Lifetime Imaging (MFLI) as a unique feature of optical imaging to quantitate in vivo drug-target engagement. MFLI quantitatively reports on nanoscale interactions via lifetime-sensing of Förster Resonance Energy Transfer (FRET) in live, intact animals. Hence, MFLI FRET acts as a direct reporter of receptor dimerization and target engagement via the measurement of the fraction of labeled-donor entity undergoing binding to its respective receptor. MFLI is expected to greatly impact preclinical imaging and also adjacent fields such as image-guided surgery and drug development.
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Affiliation(s)
- Marien Ochoa
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alena Rudkouskaya
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY, USA
| | - Jason T Smith
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Margarida Barroso
- Department of Cellular and Molecular Physiology, Albany Medical College, Albany, NY, USA.
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3
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Pian Q, Yao R, Intes X. Hyperspectral wide-field time domain single-pixel diffuse optical tomography platform. BIOMEDICAL OPTICS EXPRESS 2018; 9:6258-6272. [PMID: 31065427 PMCID: PMC6491017 DOI: 10.1364/boe.9.006258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/27/2018] [Accepted: 09/09/2018] [Indexed: 05/18/2023]
Abstract
We present the design and comprehensive instrumental characterization of a time domain diffuse optical tomography (TD-DOT) platform based on wide-field illumination and wide-field hyperspectral time-resolved single-pixel detection for functional and molecular imaging in turbid media. The proposed platform combines two digital micro-mirror devices (DMDs) to generate structured light and a spectrally resolved multi-anode photomultiplier tube (PMT) detector in time domain for hyperspectral data acquisition over 16 wavelength channels based on the time-correlated single-photon counting (TCSPC) technique. The design of the proposed platform is described in detail and its characteristics in spatial, temporal and spectral dimensions are calibrated and presented. The performance of the system is further validated through a phantom study where two absorbers in glass tubes with spectral contrast are mapped in a turbid medium of ~20 mm thickness. The method presented here offers the potential of accelerating the imaging process and improving reconstruction results in TD-DOT and thus facilitates its wide spread use in preclinical and clinical in vivo imaging scenarios.
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Affiliation(s)
- Qi Pian
- Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
- Currently with Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Ruoyang Yao
- Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Xavier Intes
- Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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4
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Yao R, Intes X, Fang Q. Direct approach to compute Jacobians for diffuse optical tomography using perturbation Monte Carlo-based photon "replay". BIOMEDICAL OPTICS EXPRESS 2018; 9:4588-4603. [PMID: 30319888 PMCID: PMC6179418 DOI: 10.1364/boe.9.004588] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/02/2018] [Accepted: 08/08/2018] [Indexed: 05/21/2023]
Abstract
Perturbation Monte Carlo (pMC) has been previously proposed to rapidly recompute optical measurements when small perturbations of optical properties are considered, but it was largely restricted to changes associated with prior tissue segments or regions-of-interest. In this work, we expand pMC to compute spatially and temporally resolved sensitivity profiles, i.e. the Jacobians, for diffuse optical tomography (DOT) applications. By recording the pseudo random number generator (PRNG) seeds of each detected photon, we are able to "replay" all detected photons to directly create the 3D sensitivity profiles for both absorption and scattering coefficients. We validate the replay-based Jacobians against the traditional adjoint Monte Carlo (aMC) method, and demonstrate the feasibility of using this approach for efficient 3D image reconstructions using in vitro hyperspectral wide-field DOT measurements. The strengths and limitations of the replay approach regarding its computational efficiency and accuracy are discussed, in comparison with aMC, for point-detector systems as well as wide-field pattern-based and hyperspectral imaging systems. The replay approach has been implemented in both of our open-source MC simulators - MCX and MMC (http://mcx.space).
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Affiliation(s)
- Ruoyang Yao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180,
USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180,
USA
| | - Qianqian Fang
- Department of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, MA 02115,
USA
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5
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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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6
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Kumar ATN, Hou SS. Tomographic phosphorescence lifetime multiplexing. OPTICS LETTERS 2018; 43:3104-3107. [PMID: 29957792 PMCID: PMC6129473 DOI: 10.1364/ol.43.003104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/28/2018] [Indexed: 06/08/2023]
Abstract
We present a tomographic reconstruction algorithm for recovering distributions of multiple phosphorescent dyes within turbid media from time-resolved measurements, using either point or spatially patterned sources and detectors. The algorithm employs a multi-exponential analysis of time-resolved data, followed by tomographic inversion of the decay amplitudes to recover independent yield distributions for each lifetime present in the medium. Using Monte Carlo simulations, we computationally demonstrate that this two-step inversion approach provides several-fold improvement in quantitative and localization accuracy compared to a direct inversion of the time domain phosphorescence. We also demonstrate the tomographic reconstruction of up to three phosphorescent lifetimes embedded in thick tissue. The proposed algorithm can allow quantitative multiplexed tomography of luminescent and phosphorescent dyes for a wide range of in vivo applications.
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Affiliation(s)
- Anand T. N. Kumar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Steven S. Hou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
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7
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Kumar ATN, Hou SS, Rice WL. Tomographic fluorescence lifetime multiplexing in the spatial frequency domain. OPTICA 2018; 5:624-627. [PMID: 30984803 PMCID: PMC6457659 DOI: 10.1364/optica.5.000624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/20/2018] [Indexed: 05/03/2023]
Abstract
The ability to simultaneously recover multiple fluorophores within biological tissue (multiplexing) can have important applications for tracking parallel disease processes in vivo. Here we present a novel method for rapid and quantitative multiplexing within a scattering medium, such as biological tissue, based on fluorescence lifetime contrast. This method employs a tomographic inversion of the asymptotic (late) portion of time-resolved spatial frequency (SF) domain measurements. Using Monte Carlo simulations and phantom experiments, we show that the SF-asymptotic time domain (SF-ATD) approach provides a several-fold improvement in relative quantitation and localization accuracy over conventional SF-time domain inversion. We also show that the SF-ATD approach can exploit selective filtering of high spatial frequencies to dramatically improve reconstruction accuracy for fluorophores with subnanosecond lifetimes, which is typical of most near-infrared fluorophores. These results suggest that the SF-ATD approach will serve as a powerful new tool for whole-body lifetime multiplexing.
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Affiliation(s)
- Anand T. N. Kumar
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Steven S. Hou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, 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
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8
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Farina A, Betcke M, di Sieno L, Bassi A, Ducros N, Pifferi A, Valentini G, Arridge S, D'Andrea C. Multiple-view diffuse optical tomography system based on time-domain compressive measurements. OPTICS LETTERS 2017; 42:2822-2825. [PMID: 28708178 DOI: 10.1364/ol.42.002822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Compressive sensing is a powerful tool to efficiently acquire and reconstruct an image even in diffuse optical tomography (DOT) applications. In this work, a time-resolved DOT system based on structured light illumination, compressive detection, and multiple view acquisition has been proposed and experimentally validated on a biological tissue-mimicking phantom. The experimental scheme is based on two digital micromirror devices for illumination and detection modulation, in combination with a time-resolved single element detector. We fully validated the method and demonstrated both the imaging and tomographic capabilities of the system, providing state-of-the-art reconstruction quality.
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9
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Yao R, Intes X, Fang Q. Generalized mesh-based Monte Carlo for wide-field illumination and detection via mesh retessellation. BIOMEDICAL OPTICS EXPRESS 2016; 7:171-84. [PMID: 26819826 PMCID: PMC4722901 DOI: 10.1364/boe.7.000171] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/12/2015] [Accepted: 12/12/2015] [Indexed: 05/18/2023]
Abstract
Monte Carlo methods are commonly used as the gold standard in modeling photon transport through turbid media. With the rapid development of structured light applications, an accurate and efficient method capable of simulating arbitrary illumination patterns and complex detection schemes over large surface area is in great need. Here we report a generalized mesh-based Monte Carlo algorithm to support a variety of wide-field illumination methods, including spatial-frequency-domain imaging (SFDI) patterns and arbitrary 2-D patterns. The extended algorithm can also model wide-field detectors such as a free-space CCD camera. The significantly enhanced flexibility of source and detector modeling is achieved via a fast mesh retessellation process that combines the target domain and the source/detector space in a single tetrahedral mesh. Both simulations of complex domains and comparisons with phantom measurements are included to demonstrate the flexibility, efficiency and accuracy of the extended algorithm. Our updated open-source software is provided at http://mcx.space/mmc.
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Affiliation(s)
- Ruoyang Yao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Qianqian Fang
- Department of Bioengineering, Northeastern University, 360 Huntington Ave, Boston, MA 02115, USA
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10
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Chen SJ, Sinsuebphon N, Intes X. Assessment of Gate Width Size on Lifetime-Based Förster Resonance Energy Transfer Parameter Estimation. PHOTONICS 2015; 2:1027-1042. [PMID: 26557647 PMCID: PMC4636205 DOI: 10.3390/photonics2041027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Förster Resonance Energy Transfer (FRET) enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity) can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.
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Affiliation(s)
| | | | - Xavier Intes
- Author to whom correspondence should be addressed; ; Tel.: +1-518-276-6964
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11
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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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12
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Pian Q, Yao R, Zhao L, Intes X. Hyperspectral time-resolved wide-field fluorescence molecular tomography based on structured light and single-pixel detection. OPTICS LETTERS 2015; 40:431-4. [PMID: 25680065 PMCID: PMC4638422 DOI: 10.1364/ol.40.000431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We present a time-resolved fluorescence diffuse optical tomography platform that is based on wide-field structured illumination, single-pixel detection, and hyperspectral acquisition. Two spatial light modulators (digital micro-mirror devices) are employed to generate independently wide-field illumination and detection patterns, coupled with a 16-channel spectrophotometer detection module to capture hyperspectral time-resolved tomographic data sets. The main system characteristics are reported, and we demonstrate the feasibility of acquiring dense 4D tomographic data sets (space, time, spectra) for time domain 3D quantitative multiplexed fluorophore concentration mapping in turbid media.
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Affiliation(s)
- Qi Pian
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Ruoyang Yao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Lingling Zhao
- 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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13
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Omer T, Zhao L, Intes X, Hahn J. Reduced temporal sampling effect on accuracy of time-domain fluorescence lifetime Förster resonance energy transfer. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086023. [PMID: 25166472 PMCID: PMC4147194 DOI: 10.1117/1.jbo.19.8.086023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/30/2014] [Indexed: 05/04/2023]
Abstract
Fluorescence lifetime imaging (FLIM) aims at quantifying the exponential decay rate of fluorophores to yield lifetime maps over the imaged sample. When combined with Förster resonance energy transfer (FRET), the technique can be used to indirectly sense interactions at the nanoscale such as protein–protein interactions, protein–DNA interactions, and protein conformational changes. In the case of FLIM-FRET, the fluorescence intensity decays are fitted to a biexponential model in order to estimate the lifetime and fractional amplitude coefficients of each component of the population of the donor fluorophore (quenched and nonquenched). Numerous time data points, also called temporal or time gates, are typically employed for accurately estimating the model parameters, leading to lengthy acquisition times and significant computational demands. This work investigates the effect of the number and location of time gates on model parameter estimation accuracy. A detailed model of a FLIM-FRET imaging system is used for the investigation, and the simulation outcomes are validated with in vitro and in vivo experimental data. In all cases investigated, it is found that 10 equally spaced time gates allow robust estimation of model-based parameters with accuracy similar to that of full temporal datasets (90 gates).
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Affiliation(s)
- Travis Omer
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Lingling Zhao
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Xavier Intes
- Rensselaer Polytechnic Institute, Department of Biomedical Engineering, 110 8th Street, Troy, New York 12180, United States
| | - Juergen Hahn
- Rensselaer Polytechnic Institute, Departments of Biomedical Engineering and Chemical & Biological Engineering, 110 8th Street, Troy, New York 12180, United States
- Address all correspondence to: Juergen Hahn, E-mail:
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14
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Behrooz A, Eftekhar AA, Adibi A. Hadamard multiplexed fluorescence tomography. BIOMEDICAL OPTICS EXPRESS 2014; 5:763-77. [PMID: 24688812 PMCID: PMC3959853 DOI: 10.1364/boe.5.000763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/10/2014] [Accepted: 02/05/2014] [Indexed: 05/22/2023]
Abstract
Depth-resolved three-dimensional (3D) reconstruction of fluorophore-tagged inclusions in fluorescence tomography (FT) poses a highly ill-conditioned problem as depth information must be extracted from boundary data. Due to the ill-posed nature of the FT inverse problem, noise and errors in the data can severely impair the accuracy of the 3D reconstructions. The signal-to-noise ratio (SNR) of the FT data strongly affects the quality of the reconstructions. Additionally, in FT scenarios where the fluorescent signal is weak, data acquisition requires lengthy integration times that result in excessive FT scan periods. Enhancing the SNR of FT data contributes to the robustness of the 3D reconstructions as well as the speed of FT scans. A major deciding factor in the SNR of the FT data is the power of the radiation illuminating the subject to excite the administered fluorescent reagents. In existing single-point illumination FT systems, the source power level is limited by the skin maximum radiation exposure levels. In this paper, we introduce and study the performance of a multiplexed fluorescence tomography system with orders-of-magnitude enhanced data SNR over existing systems. The proposed system allows for multi-point illumination of the subject without jeopardizing the information content of the FT measurements and results in highly robust reconstructions of fluorescent inclusions from noisy FT data. Improvements offered by the proposed system are validated by numerical and experimental studies.
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15
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Zhao L, Abe K, Rajoria S, Pian Q, Barroso M, Intes X. Spatial light modulator based active wide-field illumination for ex vivo and in vivo quantitative NIR FRET imaging. BIOMEDICAL OPTICS EXPRESS 2014; 5:944-60. [PMID: 24688826 PMCID: PMC3959842 DOI: 10.1364/boe.5.000944] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/20/2014] [Accepted: 01/31/2014] [Indexed: 05/20/2023]
Abstract
Fluorescence lifetime imaging is playing an increasing role in drug development by providing a sensitive method to monitor drug delivery and receptor-ligand interactions. However, the wide dynamic range of fluorescence intensity emitted by ex vivo and in vivo samples presents challenges in retrieving information over the whole subject accurately and quantitatively. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy based on a spatial light modulator that acquires optimal fluorescence signals by enhancing the dynamic range, signal to noise ratio, and estimation of lifetime-based parameters. We demonstrate the ability of AWFI to estimate Förster resonance energy transfer (FRET) donor fraction from dissected organs with high accuracy (standard deviation <6%) over the whole field of view, in contrast with the homogenous wide-field illumination. We further report its successful application to quantitative FRET imaging in a live mouse. AWFI allows improved detection of weak signals and enhanced quantitative accuracy in ex vivo and in vivo molecular fluorescence quantitative imaging. The technique allows for robust quantitative estimation of the bio-distribution of molecular probes and lifetime-based parameters over an extended imaging field exhibiting a large range of fluorescence intensities and at a high acquisition speed (less than 1 min).
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Affiliation(s)
- Lingling Zhao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Ken Abe
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, NY 12208, USA
| | - Shilpi Rajoria
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, NY 12208, USA
| | - Qi Pian
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Margarida Barroso
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, NY 12208, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
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Zhao L, Abe K, Barroso M, Intes X. Active wide-field illumination for high-throughput fluorescence lifetime imaging. OPTICS LETTERS 2013; 38:3976-9. [PMID: 24081103 PMCID: PMC3933959 DOI: 10.1364/ol.38.003976] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Wide-field fluorescence lifetime imaging allows for fast imaging of large sample areas at the cost of low sensitivity to weak fluorescence signals. To overcome this challenge, we developed an active wide-field illumination (AWFI) strategy to optimize the impinging spatial intensity for acquiring optimal fluorescence signals over the whole sample. We demonstrated the ability of AWFI to accurately estimate lifetimes from a multiwell plate sample with concentrations ranging over two orders of magnitude. We further reported its successful application to a quantitative Förster resonance energy transfer lifetime cell-based assay. Overall, this method allows for enhanced accuracy in lifetime-based imaging at high acquisition speed over samples with large fluorescence intensity distributions.
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Affiliation(s)
- Lingling Zhao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Ken Abe
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, New York 12208, USA
| | - Margarida Barroso
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Avenue, Albany, New York 12208, USA
| | - Xavier Intes
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Corresponding author:
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Guggenheim JA, Basevi HRA, Frampton J, Styles IB, Dehghani H. Multi-modal molecular diffuse optical tomography system for small animal imaging. MEASUREMENT SCIENCE & TECHNOLOGY 2013; 24:105405. [PMID: 24954977 PMCID: PMC4061700 DOI: 10.1088/0957-0233/24/10/105405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A multi-modal optical imaging system for quantitative 3D bioluminescence and functional diffuse imaging is presented, which has no moving parts and uses mirrors to provide multi-view tomographic data for image reconstruction. It is demonstrated that through the use of trans-illuminated spectral near infrared measurements and spectrally constrained tomographic reconstruction, recovered concentrations of absorbing agents can be used as prior knowledge for bioluminescence imaging within the visible spectrum. Additionally, the first use of a recently developed multi-view optical surface capture technique is shown and its application to model-based image reconstruction and free-space light modelling is demonstrated. The benefits of model-based tomographic image recovery as compared to 2D planar imaging are highlighted in a number of scenarios where the internal luminescence source is not visible or is confounding in 2D images. The results presented show that the luminescence tomographic imaging method produces 3D reconstructions of individual light sources within a mouse-sized solid phantom that are accurately localised to within 1.5mm for a range of target locations and depths indicating sensitivity and accurate imaging throughout the phantom volume. Additionally the total reconstructed luminescence source intensity is consistent to within 15% which is a dramatic improvement upon standard bioluminescence imaging. Finally, results from a heterogeneous phantom with an absorbing anomaly are presented demonstrating the use and benefits of a multi-view, spectrally constrained coupled imaging system that provides accurate 3D luminescence images.
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Affiliation(s)
- James A Guggenheim
- Physical Science of Imaging in the Biomedical Sciences Doctoral Training Centre, College of Engineering and Physical Sciences, University of Birmingham, UK ; School of Computer Science, College of Engineering and Physical Sciences, University of Birmingham, UK
| | - Hector R A Basevi
- Physical Science of Imaging in the Biomedical Sciences Doctoral Training Centre, College of Engineering and Physical Sciences, University of Birmingham, UK ; School of Computer Science, College of Engineering and Physical Sciences, University of Birmingham, UK
| | - Jon Frampton
- School of Immunity and Infection, College of Medicine and Dentistry, University of Birmingham, UK
| | - Iain B Styles
- School of Computer Science, College of Engineering and Physical Sciences, University of Birmingham, UK
| | - Hamid Dehghani
- Physical Science of Imaging in the Biomedical Sciences Doctoral Training Centre, College of Engineering and Physical Sciences, University of Birmingham, UK ; School of Computer Science, College of Engineering and Physical Sciences, University of Birmingham, UK
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