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Pham T, Wei LL, Roblyer D. Cross-wavelength calibrating method for real-time imaging of tissue optical properties using frequency-domain diffuse optical spectroscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:4963-4979. [PMID: 39346994 PMCID: PMC11427195 DOI: 10.1364/boe.529551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 07/18/2024] [Accepted: 07/19/2024] [Indexed: 10/01/2024]
Abstract
Frequency-domain diffuse optical spectroscopy (FD-DOS) is a powerful non-invasive technique for assessing tissue optical properties, with applications ranging from basic research to clinical diagnosis. In this study, we introduce and validate a novel approach termed the cross-wavelength calibrating (CWC) method within the framework of TrackDOSI, a real-time FD-DOS imaging system for tissue characterization. The CWC method aims to mitigate the effects of changing optical coupling and motion artifacts encountered during probe scanning, thus enhancing the accuracy and reliability of optical property measurements. Notably, the CWC method also allows for a simpler geometry with fewer sources than traditional self-calibrating (SC) methods, reducing instrumental complexity and cost while maintaining robustness in estimating optical properties. We first validate the CWC method on solid silicone phantoms, demonstrating strong agreement with the gold standard SC method with an error of -10% and 1% for absorption and reduced scattering coefficients, respectively. Furthermore, experiments on phantom and human tissue reveal the CWC approach's ability to suppress motion artifacts and optical coupling variations, thereby improving measurement repeatability, signal fidelity, and artifact correction in dynamic imaging scenarios. Our findings underscore the potential of the CWC method to enhance the clinical utility of DOSI techniques by enabling real-time artifact correction and improving the accuracy of tissue optical property measurements.
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Affiliation(s)
- Thao Pham
- Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, USA
| | - Lina Lin Wei
- Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, USA
| | - Darren Roblyer
- Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston, MA 02215, USA
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2
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Galve P, Arias-Valcayo F, Villa-Abaunza A, Ibáñez P, Udías JM. UMC-PET: a fast and flexible Monte Carlo PET simulator. Phys Med Biol 2024; 69:035018. [PMID: 38198727 DOI: 10.1088/1361-6560/ad1cf9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 01/10/2024] [Indexed: 01/12/2024]
Abstract
Objective.The GPU-based Ultra-fast Monte Carlo positron emission tomography simulator (UMC-PET) incorporates the physics of the emission, transport and detection of radiation in PET scanners. It includes positron range, non-colinearity, scatter and attenuation, as well as detector response. The objective of this work is to present and validate UMC-PET as a a multi-purpose, accurate, fast and flexible PET simulator.Approach.We compared UMC-PET against PeneloPET, a well-validated MC PET simulator, both in preclinical and clinical scenarios. Different phantoms for scatter fraction (SF) assessment following NEMA protocols were simulated in a 6R-SuperArgus and a Biograph mMR scanner, comparing energy histograms, NEMA SF, and sensitivity for different energy windows. A comparison with real data reported in the literature on the Biograph scanner is also shown.Main results.NEMA SF and sensitivity estimated by UMC-PET where within few percent of PeneloPET predictions. The discrepancies can be attributed to small differences in the physics modeling. Running in a 11 GB GeForce RTX 2080 Ti GPU, UMC-PET is ∼1500 to ∼2000 times faster than PeneloPET executing in a single core Intel(R) Xeon(R) CPU W-2155 @ 3.30 GHz.Significance.UMC-PET employs a voxelized scheme for the scanner, patient adjacent objects (such as shieldings or the patient bed), and the activity distribution. This makes UMC-PET extremely flexible. Its high simulation speed allows applications such as MC scatter correction, faster SRM estimation for complex scanners, or even MC iterative image reconstruction.
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Affiliation(s)
- Pablo Galve
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
- Université Paris Cité, Inserm, PARCC, F-75015 Paris, France
- Health Research Institute of the Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Fernando Arias-Valcayo
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Amaia Villa-Abaunza
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
| | - Paula Ibáñez
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - José Manuel Udías
- Grupo de Física Nuclear, EMFTEL & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clínico San Carlos (IdISSC), Madrid, Spain
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Walter AB, Jansen ED. Development of a platform for broadband, spectra-fitted, tissue optical phantoms. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:025001. [PMID: 36814953 PMCID: PMC9940728 DOI: 10.1117/1.jbo.28.2.025001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
SIGNIFICANCE Current methods of producing optical phantoms are incapable of accurately capturing the wavelength-dependent properties of tissue critical for many optical modalities. AIM We aim to introduce a method of producing solid, inorganic phantoms whose wavelength-dependent optical properties can be matched to those of tissue over the wavelength range of 370 to 950 nm. APPROACH The concentration-dependent optical properties of 20 pigments were characterized and used to determine combinations that result in optimal fits compared to the target properties over the full spectrum. Phantoms matching the optical properties of muscle and nerve, the diffuse reflectance of pale and melanistic skin, and the chromophore concentrations of a computational skin model with varying oxygen saturation ( StO 2 ) were made with this method. RESULTS Both optical property phantoms were found to accurately mimic their respective tissues' absorption and scattering properties across the entire spectrum. The diffuse reflectance phantoms were able to closely approximate skin reflectance regardless of skin type. All three computational skin phantoms were found to have emulated chromophore concentrations close to the model, with an average percent error for the StO 2 of 4.31%. CONCLUSIONS This multipigment phantom platform represents a powerful tool for creating spectrally accurate tissue phantoms, which should increase the availability of standards for many optical techniques.
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Affiliation(s)
- Alec B. Walter
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
- Vanderbilt University, Biophotonics Center, Nashville, Tennessee, United States
| | - E. Duco Jansen
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
- Vanderbilt University, Biophotonics Center, Nashville, Tennessee, United States
- Vanderbilt University Medical Center, Department of Neurosurgery, Nashville, Tennessee, United States
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Parilov E, Beeson K, Potasek M, Zhu T, Sun H, Sourvanos D. A Monte Carlo simulation for Moving Light Source in Intracavity PDT. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12359:1235903. [PMID: 37206985 PMCID: PMC10194003 DOI: 10.1117/12.2649538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We developed a simulation method for modeling the light fluence delivery in intracavity Photodynamic Therapy (icav-PDT) for pleural lung cancer using a moving light source. Due to the large surface area of the pleural lung cavity, the light source needs to be moved to deliver a uniform dose around the entire cavity. While multiple fixed detectors are used for dosimetry at a few locations, an accurate simulation of light fluence and fluence rate is still needed for the rest of the cavity. We extended an existing Monte Carlo (MC) based light propagation solver to support moving light sources by densely sampling the continuous light source trajectory and assigning the proper number of photon packages launched along the way. The performance of Simphotek GPU CUDA-based implementation of the method - PEDSy-MC - has been demonstrated on a life-size lung-shaped phantom, custom printed for testing icav-PDT navigation system at the Perlman School of Medicine (PSM) - calculations completed under a minute (for some cases) and within minutes have been achieved. We demonstrate results within a 5% error of the analytic solution for multiple detectors in the phantom. PEDSy-MC is accompanied by a dose-cavity visualization tool that allows real-time inspection of dose values of the treated cavity in 2D and 3D, which will be expanded to ongoing clinical trials at PSM. PSM has developed a technology to measure 8-detectors in a pleural cavity phantom using Photofrin-mediated PDT that has been used during validation.
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Affiliation(s)
| | - Karl Beeson
- Simphotek, Inc., 211 Warren St., Newark, NJ 07103
| | - Mary Potasek
- Simphotek, Inc., 211 Warren St., Newark, NJ 07103
| | - Timothy Zhu
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hongjing Sun
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dennis Sourvanos
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Pattelli L, Mazzamuto G. Experimental imaging and Monte Carlo modeling of ultrafast pulse propagation in thin scattering slabs. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:083020. [PMID: 35655345 PMCID: PMC9162504 DOI: 10.1117/1.jbo.27.8.083020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Most radiative transport problems in turbid media are typically associated with mm or cm scales, leading to typical time scales in the range of hundreds of ps or more. In certain cases, however, much thinner layers can also be relevant, which can dramatically alter the overall transport properties of a scattering medium. Studying scattering in these thin layers requires ultrafast detection techniques and adaptations to the common Monte Carlo (MC) approach. AIM We aim to discuss a few relevant aspects for the simulation of light transport in thin scattering membranes, and compare the obtained numerical results with experimental measurements based on an all-optical gating technique. APPROACH A thin membrane with controlled scattering properties based on polymer-dispersed TiO2 nanoparticles is fabricated for experimental validation. Transmittance measurements are compared against a custom open-source MC implementation including specific pulse profiles for tightly focused femtosecond laser pulses. RESULTS Experimental transmittance data of ultrafast pulses through a thin scattering sample are compared with MC simulations in the spatiotemporal domain to retrieve its scattering properties. The results show good agreement also at short distances and time scales. CONCLUSIONS When simulating light transport in scattering membranes with thicknesses in the orders of tens of micrometer, care has to be taken when describing the temporal, spatial, and divergence profiles of the source term, as well as the possible truncation of step length distributions, which could be introduced by simple strategies for the generation of random exponentially distributed variables.
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Affiliation(s)
- Lorenzo Pattelli
- Istituto Nazionale di Ricerca Metrologica (INRiM), Torino, Italy
- European Laboratory for Nonlinear Spectroscopy (LENS), Sesto Fiorentino, Italy
| | - Giacomo Mazzamuto
- European Laboratory for Nonlinear Spectroscopy (LENS), Sesto Fiorentino, Italy
- Istituto Nazionale di Ottica (INO), CNR, Sesto Fiorentino, Italy
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Abstract
Diffuse optical tomography using deep learning is an emerging technology that has found impressive medical diagnostic applications. However, creating an optical imaging system that uses visible and near-infrared (NIR) light is not straightforward due to photon absorption and multi-scattering by tissues. The high distortion levels caused due to these effects make the image reconstruction incredibly challenging. To overcome these challenges, various techniques have been proposed in the past, with varying success. One of the most successful techniques is the application of deep learning algorithms in diffuse optical tomography. This article discusses the current state-of-the-art diffuse optical tomography systems and comprehensively reviews the deep learning algorithms used in image reconstruction. This article attempts to provide researchers with the necessary background and tools to implement deep learning methods to solve diffuse optical tomography.
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Spatial-Frequency Domain Imaging: An Emerging Depth-Varying and Wide-Field Technique for Optical Property Measurement of Biological Tissues. PHOTONICS 2021. [DOI: 10.3390/photonics8050162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Measurement of optical properties is critical for understanding light-tissue interaction, properly interpreting measurement data, and gaining better knowledge of tissue physicochemical properties. However, conventional optical measuring techniques are limited in point measurement, which partly hinders the applications on characterizing spatial distribution and inhomogeneity of optical properties of biological tissues. Spatial-frequency domain imaging (SFDI), as an emerging non-contact, depth-varying and wide-field optical imaging technique, is capable of measuring the optical properties in a wide field-of-view on a pixel-by-pixel basis. This review first describes the typical SFDI system and the principle for estimating optical properties using the SFDI technique. Then, the applications of SFDI in the fields of biomedicine, as well as food and agriculture, are reviewed, including burn assessment, skin tissue evaluation, tumor tissue detection, brain tissue monitoring, and quality evaluation of agro-products. Finally, a discussion on the challenges and future perspectives of SFDI for optical property estimation is presented.
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Yang L, Wabnitz H, Gladytz T, Sudakou A, Macdonald R, Grosenick D. Space-enhanced time-domain diffuse optics for determination of tissue optical properties in two-layered structures. BIOMEDICAL OPTICS EXPRESS 2020; 11:6570-6589. [PMID: 33282509 PMCID: PMC7687957 DOI: 10.1364/boe.402181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 05/05/2023]
Abstract
A novel methodology for solving the inverse problem of diffuse optics for two-layered structures is proposed to retrieve the absolute quantities of optical absorption and reduced scattering coefficients of the layers simultaneously. A liquid phantom with various optical absorption properties in the deep layer is prepared and experimentally investigated using the space-enhanced time-domain method. Monte-Carlo simulations are applied to analyze the different measurements in time domain, space domain, and by the new methodology. The deviations of retrieved values from nominal values of both layers' optical properties are simultaneously reduced to a very low extent compared to the single-domain methods. The reliability and uncertainty of the retrieval performance are also considerably improved by the new methodology. It is observed in time-domain analyses that for the deep layer the retrieval of absorption coefficient is almost not affected by the scattering properties and this kind of "deep scattering neutrality" is investigated and overcome as well.
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Affiliation(s)
- Lin Yang
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Thomas Gladytz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Aleh Sudakou
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 02-109 Warsaw, Poland
| | - Rainer Macdonald
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
- Institute of Optics and Atomic Physics, Technical University of Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Dirk Grosenick
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
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Leino AA, Lunttila T, Mozumder M, Pulkkinen A, Tarvainen T. Perturbation Monte Carlo Method for Quantitative Photoacoustic Tomography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:2985-2995. [PMID: 32217473 DOI: 10.1109/tmi.2020.2983129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Quantitative photoacoustic tomography aims at estimating optical parameters from photoacoustic images that are formed utilizing the photoacoustic effect caused by the absorption of an externally introduced light pulse. This optical parameter estimation is an ill-posed inverse problem, and thus it is sensitive to measurement and modeling errors. In this work, we propose a novel way to solve the inverse problem of quantitative photoacoustic tomography based on the perturbation Monte Carlo method. Monte Carlo method for light propagation is a stochastic approach for simulating photon trajectories in a medium with scattering particles. It is widely accepted as an accurate method to simulate light propagation in tissues. Furthermore, it is numerically robust and easy to implement. Perturbation Monte Carlo maintains this robustness and enables forming gradients for the solution of the inverse problem. We validate the method and apply it in the framework of Bayesian inverse problems. The simulations show that the perturbation Monte Carlo method can be used to estimate spatial distributions of both absorption and scattering parameters simultaneously. These estimates are qualitatively good and quantitatively accurate also in parameter scales that are realistic for biological tissues.
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10
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Hu D, Sun T, Yao L, Yang Z, Wang A, Ying Y. Monte Carlo: A flexible and accurate technique for modeling light transport in food and agricultural products. Trends Food Sci Technol 2020. [DOI: 10.1016/j.tifs.2020.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Foschum F, Bergmann F, Kienle A. Precise determination of the optical properties of turbid media using an optimized integrating sphere and advanced Monte Carlo simulations. Part 1: theory. APPLIED OPTICS 2020; 59:3203-3215. [PMID: 32400605 DOI: 10.1364/ao.386011] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper, we describe a method used to determine the optical properties, namely, the effective scattering and absorption coefficients, employing an optimized three-dimensional-printed single integrating sphere. The paper consists of two parts, and in Part 1, the theoretical investigation of an optimized measurement and the evaluation routine are presented. Using an analytical and a numerical model for the optical characterization of the integrating sphere, errors caused by the application of a non-ideal sphere (the one with ports or baffles) were investigated. Considering this research, a procedure for the precise determination of the optical properties, based on Monte Carlo simulations of the light distribution within the sample, was developed. In Part 2, we present the experimental validation of this procedure.
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12
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Broadband Time Domain Diffuse Optical Reflectance Spectroscopy: A Review of Systems, Methods, and Applications. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245465] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review presents recent developments and a wide overview of broadband time domain diffuse optical spectroscopy (TD-DOS). Various topics including physics of photon migration, advanced instrumentation, methods of analysis, applications covering multiple domains (tissue chromophore, in vivo studies, food, wood, pharmaceutical industry) are elaborated. The key role of standardization and recent studies in that direction are discussed. Towards the end, a brief outlook is presented on the current status and future trends in broadband TD-DOS.
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13
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Bengtsson A, Hill D, Li M, Di M, Cinthio M, Erlöv T, Andersson-Engels S, Reistad N, Walther A, Rippe L, Kröll S. Characterization and modeling of acousto-optic signal strengths in highly scattering media. BIOMEDICAL OPTICS EXPRESS 2019; 10:5565-5584. [PMID: 31799031 PMCID: PMC6865126 DOI: 10.1364/boe.10.005565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/20/2019] [Accepted: 09/04/2019] [Indexed: 05/31/2023]
Abstract
Ultrasound optical tomography (UOT) is an imaging technique based on the acousto-optic effect that can perform optical imaging with ultrasound resolution inside turbid media, and is thus interesting for biomedical applications, e.g. for assessing tissue blood oxygenation. In this paper, we present near background free measurements of UOT signal strengths using slow light filter signal detection. We carefully analyze each part of our experimental setup and match measured signal strengths with calculations based on diffusion theory. This agreement between experiment and theory allows us to assert the deep tissue imaging potential of ∼ 5 cm for UOT of real human tissues predicted by previous theoretical studies [Biomed. Opt. Express8, 4523 (2017)] with greater confidence, and indicate that future theoretical analysis of optimized UOT systems can be expected to be reliable.
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Affiliation(s)
| | - David Hill
- Department of Physics, Lund University, 221
00 Lund, Sweden
- SpectraCure AB, 222 29 Lund, Sweden
| | - Meng Li
- Department of Physics, Lund University, 221
00 Lund, Sweden
| | - Mengqiao Di
- Department of Physics, Lund University, 221
00 Lund, Sweden
- Department of Chemistry and Chemical
Engineering, Chalmers University of Technology, 412 96 Gothenburg,
Sweden
| | - Magnus Cinthio
- Department of Biomedical Engineering, Lund
University, 221 00 Lund, Sweden
| | - Tobias Erlöv
- Department of Biomedical Engineering, Lund
University, 221 00 Lund, Sweden
| | - Stefan Andersson-Engels
- Tyndall National Institute, Lee Maltings,
Dyke Parade, Cork, T12 R5CP, Ireland
- Department of Physics, University College
Cork, Cork, Ireland
| | - Nina Reistad
- Department of Physics, Lund University, 221
00 Lund, Sweden
| | | | - Lars Rippe
- Department of Physics, Lund University, 221
00 Lund, Sweden
| | - Stefan Kröll
- Department of Physics, Lund University, 221
00 Lund, Sweden
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Yang L, Wabnitz H, Gladytz T, Macdonald R, Grosenick D. Spatially-enhanced time-domain NIRS for accurate determination of tissue optical properties. OPTICS EXPRESS 2019; 27:26415-26431. [PMID: 31674524 DOI: 10.1364/oe.27.026415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A multivariate method integrating time and space resolved techniques of near-infrared spectroscopy is proposed for simultaneously retrieving the absolute quantities of optical absorption and scattering properties in tissues. The time-domain feature of photon migration is advantageously constrained and regularized by its spatially-resolved amplitude patterns in the inverse procedure. Measurements of tissue-mimicking phantoms with various optical properties are analyzed with Monte-Carlo simulations to validate the method performance. The uniqueness, stability, and uncertainty of the method are discussed.
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15
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Mahmoodkalayeh S, Ansari MA, Tuchin VV. Head model based on the shape of the subject's head for optical brain imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:2795-2808. [PMID: 31259052 PMCID: PMC6583357 DOI: 10.1364/boe.10.002795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 05/05/2023]
Abstract
Optical imaging methods such as near-infrared spectroscopy and diffuse optical tomography rely on models to solve the inverse problem. Imaging an adult human head also requires a head model. Using a model, which makes describing the structure of the head better, leads to acquiring a more accurate absorption map. Here, by combining the key features of layered slab models and head atlases, we introduce a new two-layered head model that is based on the surface geometry of the subject's head with variable thickness of the superficial layer. Using the Monte Carlo approach, we assess the performance of our model for fitting the optical properties from simulated time-resolved data of the adult head in a null distance source-detector configuration. Using our model, we observed improved results at 70 percent of the locations on the head and an overall 20 percent reduction in relative error compared to layered slab model.
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Affiliation(s)
- Sadreddin Mahmoodkalayeh
- Department of Physics, Shahid Beheshti University, Velenjak, Tehran, Iran
- Laser and Plasma Research Institute, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Mohammad Ali Ansari
- Laser and Plasma Research Institute, Shahid Beheshti University, 1983969411, Tehran, Iran
| | - Valery V. Tuchin
- Research-Educational Institute of Optics and Biophotonics, Saratov State University, Saratov, Russia
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
- Laboratory of Laser Diagnostics of Technical and Living Systems, Institute of Precision Mechanics and Control of the Russian Academy of Sciences, Saratov, Russia
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Abstract
This article reviews the past and current statuses of time-domain near-infrared spectroscopy (TD-NIRS) and imaging. Although time-domain technology is not yet widely employed due to its drawbacks of being cumbersome, bulky, and very expensive compared to commercial continuous wave (CW) and frequency-domain (FD) fNIRS systems, TD-NIRS has great advantages over CW and FD systems because time-resolved data measured by TD systems contain the richest information about optical properties inside measured objects. This article focuses on reviewing the theoretical background, advanced theories and methods, instruments, and studies on clinical applications for TD-NIRS including some clinical studies which used TD-NIRS systems. Major events in the development of TD-NIRS and imaging are identified and summarized in chronological tables and figures. Finally, prospects for TD-NIRS in the near future are briefly described.
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17
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Zoller C, Kienle A. Fast and precise image generation of blood vessels embedded in skin. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-9. [PMID: 30693701 PMCID: PMC6985685 DOI: 10.1117/1.jbo.24.1.015002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/09/2019] [Indexed: 05/12/2023]
Abstract
A software for fast rendering the visual appearance of a blood vessel located in human skin was developed based on a numerical solution of the radiative transfer equation. The user can specify geometrical properties, such as the depth and the diameter of the vessel, and physiological properties, such as the oxygen saturation of the vessel or the blood concentration in the skin. From these data, the spatially and spectrally resolved reflectance from the skin containing the blood vessel is calculated via Monte Carlo simulations, by which a two-dimensional image is generated. The short calculation time of about a second is achieved by precalculating and storing the spatially resolved reflectance for a variety of combinations of the optical and geometrical properties. This concept gives the user the opportunity to rapidly explore the influence of the physiological and geometrical properties of the investigated blood vessel on its visual appearance. The correctness of the lookup table was validated by comparison with independent Monte Carlo simulations. Rendering examples of different blood vessels in human skins are given. The current version of the software can be downloaded at https://www.ilm-ulm.de/software.
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Affiliation(s)
- Christian Zoller
- Institute for Laser Technologies in Medicine and Metrology, Ulm, Germany
| | - Alwin Kienle
- Institute for Laser Technologies in Medicine and Metrology, Ulm, Germany
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18
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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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19
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A New Method Based on Graphics Processing Units for Fast Near-Infrared Optical Tomography. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 977:191-197. [PMID: 28685445 DOI: 10.1007/978-3-319-55231-6_26] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
The accuracy of images obtained by Diffuse Optical Tomography (DOT) could be substantially increased by the newly developed time resolved (TR) cameras. These devices result in unprecedented data volumes, which present a challenge to conventional image reconstruction techniques. In addition, many clinical applications require taking photons in air regions like the trachea into account, where the diffusion model fails. Image reconstruction techniques based on photon tracking are mandatory in those cases but have not been implemented so far due to computing demands. We aimed at designing an inversion algorithm which could be implemented on commercial graphics processing units (GPUs) by making use of information obtained with other imaging modalities. The method requires a segmented volume and an approximately uniform value for the reduced scattering coefficient in the volume under study. The complex photon path is reduced to a small number of partial path lengths within each segment resulting in drastically reduced memory usage and computation time. Our approach takes advantage of wavelength normalized data which renders it robust against instrumental biases and skin irregularities which is critical for realistic clinical applications. The accuracy of this method has been assessed with both simulated and experimental inhomogeneous phantoms showing good agreement with target values. The simulation study analyzed a phantom containing a tumor next to an air region. For the experimental test, a segmented cuboid phantom was illuminated by a supercontinuum laser and data were gathered by a state of the art TR camera. Reconstructions were obtained on a GPU-installed computer in less than 2 h. To our knowledge, it is the first time Monte Carlo methods have been successfully used for DOT based on TR cameras. This opens the door to applications such as accurate measurements of oxygenation in neck tumors where the presence of air regions is a problem for conventional approaches.
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20
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Levine ZH, Streater RH, Lieberson AMR, Pintar AL, Cooksey CC, Lemaillet P. Algorithm for rapid determination of optical scattering parameters. OPTICS EXPRESS 2017; 25:26728-26746. [PMID: 29092156 PMCID: PMC5894000 DOI: 10.1364/oe.25.026728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/11/2017] [Indexed: 05/16/2023]
Abstract
Preliminary experiments at the NIST Spectral Tri-function Automated Reference Reflectometer (STARR) facility have been conducted with the goal of providing the diffuse optical properties of a solid reference standard with optical properties similar to human skin. Here, we describe an algorithm for determining the best-fit parameters and the statistical uncertainty associated with the measurement. The objective function is determined from the profile log likelihood, including both experimental and Monte Carlo uncertainties. Initially, the log likelihood is determined over a large parameter search box using a relatively small number of Monte Carlo samples such as 2·104. The search area is iteratively reduced to include the 99.9999% confidence region, while doubling the number of samples at each iteration until the experimental uncertainty dominates over the Monte Carlo uncertainty. Typically this occurs by 1.28·106 samples. The log likelihood is then fit to determine a 95% confidence ellipse. The inverse problem requires the values of the log likelihood on many points. Our implementation uses importance sampling to calculate these points on a grid in an efficient manner. Ultimately, the time-to-solution is approximately six times the cost of a Monte Carlo simulation of the radiation transport problem for a single set of parameters with the largest number of photons required. The results are found to be 64 times faster than our implementation of Particle Swarm Optimization.
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Affiliation(s)
- Zachary H. Levine
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Richelle H. Streater
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - Anne-Michelle R. Lieberson
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Sherwood High School, Sandy Spring, Maryland 20860, USA
| | - Adam L. Pintar
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Catherine C. Cooksey
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Paul Lemaillet
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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21
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Hu D, Lu R, Ying Y. Finite element simulation of light transfer in turbid media under structured illumination. APPLIED OPTICS 2017; 56:6035-6042. [PMID: 29047929 DOI: 10.1364/ao.56.006035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
The spatial-frequency domain (SFD) imaging technique allows us to estimate the optical properties of biological tissues in a wide field of view. The technique is, however, prone to error in measurement because the two crucial assumptions used for deriving the analytical solution to the diffusion approximation cannot be met perfectly in practical applications. This research mainly focused on modeling light transfer in turbid media under the normal incidence of structured illumination using the finite element method (FEM). Finite element simulations were performed for 50 simulation samples with different combinations of optical absorption and scattering coefficients for varying spatial frequencies, and the results were then compared with the analytical method and Monte Carlo simulation. Relationships between diffuse reflectance and dimensionless absorption and dimensionless scattering coefficients were investigated. The results indicated that the FEM provided reasonable results for diffuse reflectance, compared with the analytical method. Both the FEM and the analytical method overestimated the reflectance for μtr/fx values of greater than 2 and underestimated the reflectance for μtr/fx values of smaller than 2. Larger values of μs'/μa yielded better diffuse reflectance estimations than did those of smaller than 10. The reflectance increased nonlinearly with the dimensionless scattering, whereas the reflectance decreased linearly with the dimensionless absorption. It was also observed that diffuse reflectance was relatively stable and insensitive to μs' when the dimensionless scattering was larger than 50. Overall results demonstrate that the FEM is effective for modeling light transfer in turbid media and can be used to explore the effects of crucial parameters for the SFD imaging technique.
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22
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Guggenheim JA, Bargigia I, Farina A, Pifferi A, Dehghani H. Time resolved diffuse optical spectroscopy with geometrically accurate models for bulk parameter recovery. BIOMEDICAL OPTICS EXPRESS 2016; 7:3784-3794. [PMID: 27699137 PMCID: PMC5030049 DOI: 10.1364/boe.7.003784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 05/04/2023]
Abstract
A novel straightforward, accessible and efficient approach is presented for performing hyperspectral time-domain diffuse optical spectroscopy to determine the optical properties of samples accurately using geometry specific models. To allow bulk parameter recovery from measured spectra, a set of libraries based on a numerical model of the domain being investigated is developed as opposed to the conventional approach of using an analytical semi-infinite slab approximation, which is known and shown to introduce boundary effects. Results demonstrate that the method improves the accuracy of derived spectrally varying optical properties over the use of the semi-infinite approximation.
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Affiliation(s)
- James A. Guggenheim
- PSIBS Doctoral Training Centre, University of Birmingham, Birmingham, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Ilaria Bargigia
- Center for Nano-Science and Technology @POLIMI, Istituto Italiano di Tecnologia, Milano, Italy
| | - Andrea Farina
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Milano, Italy
| | - Antonio Pifferi
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Milano, Italy
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
| | - Hamid Dehghani
- PSIBS Doctoral Training Centre, University of Birmingham, Birmingham, UK
- School of Computer Science, University of Birmingham, Birmingham, UK
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23
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Pattelli L, Savo R, Burresi M, Wiersma DS. Spatio-temporal visualization of light transport in complex photonic structures. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16090. [PMID: 30167167 PMCID: PMC6059935 DOI: 10.1038/lsa.2016.90] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/13/2016] [Accepted: 02/02/2016] [Indexed: 06/06/2023]
Abstract
Spatio-temporal imaging of light propagation is very important in photonics because it provides the most direct tool available to study the interaction between light and its host environment. Sub-ps time resolution is needed to investigate the fine and complex structural features that characterize disordered and heterogeneous structures, which are responsible for a rich array of transport physics that have not yet been fully explored. A newly developed wide-field imaging system enables us to present a spatio-temporal study on light transport in various disordered media, revealing properties that could not be properly assessed using standard techniques. By extending our investigation to an almost transparent membrane, a configuration that has been difficult to characterize until now, we unveil the peculiar physics exhibited by such thin scattering systems with transport features that go beyond mainstream diffusion modeling, despite the occurrence of multiple scattering.
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Affiliation(s)
- Lorenzo Pattelli
- European Laboratory for Non-linear Spectroscopy (LENS), Università di Firenze, Sesto Fiorentino (FI) 50019, Italy
| | - Romolo Savo
- European Laboratory for Non-linear Spectroscopy (LENS), Università di Firenze, Sesto Fiorentino (FI) 50019, Italy
| | - Matteo Burresi
- Istituto Nazionale di Ottica (CNR-INO), Firenze (FI) 50125, Italy
| | - Diederik S Wiersma
- European Laboratory for Non-linear Spectroscopy (LENS), Università di Firenze, Sesto Fiorentino (FI) 50019, Italy
- Dipartimento di Fisica e Astronomia, Università di Firenze, Sesto Fiorentino (FI) 50019, Italy
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24
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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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25
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Kamran F, Abildgaard OHA, Subash AA, Andersen PE, Andersson-Engels S, Khoptyar D. Computationally effective solution of the inverse problem in time-of-flight spectroscopy. OPTICS EXPRESS 2015; 23:6937-6945. [PMID: 25836913 DOI: 10.1364/oe.23.006937] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Photon time-of-flight (PTOF) spectroscopy enables the estimation of absorption and reduced scattering coefficients of turbid media by measuring the propagation time of short light pulses through turbid medium. The present investigation provides a comparison of the assessed absorption and reduced scattering coefficients from PTOF measurements of intralipid 20% and India ink-based optical phantoms covering a wide range of optical properties relevant for biological tissues and dairy products. Three different models are used to obtain the optical properties by fitting to measured temporal profiles: the Liemert-Kienle model (LKM), the diffusion model (DM) and a white Monte-Carlo (WMC) simulation-based algorithm. For the infinite space geometry, a very good agreement is found between the LKM and WMC, while the results obtained by the DM differ, indicating that the LKM can provide accurate estimation of the optical parameters beyond the limits of the diffusion approximation in a computational effective and accurate manner. This result increases the potential range of applications for PTOF spectroscopy within industrial and biomedical applications.
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26
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Glennie DL, Hayward JE, Farrell TJ. Modeling changes in the hemoglobin concentration of skin with total diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:035002. [PMID: 25751028 DOI: 10.1117/1.jbo.20.3.035002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 02/16/2015] [Indexed: 05/20/2023]
Abstract
The ability to monitor changes in the concentration of hemoglobin in the blood of the skin in real time is a key component to personalized patient care. Since hemoglobin has a unique absorption spectrum in the visible light range, diffuse reflectance spectroscopy is the most common approach. Although the collection of the diffuse reflectance spectrum with an integrating sphere (IS) has several calibration challenges, this collection method is sufficiently user-friendly that it may be worth overcoming the initial difficulty. Once the spectrum is obtained, it is commonly interpreted with a log-inverse-reflectance (LIR) or “absorbance” analysis that can only accurately monitor changes in the hemoglobin concentration when there are no changes to the nonhemoglobin chromophore concentrations which is not always the case. We address the difficulties associated with collection of the diffuse reflectance spectrum with an IS and propose a model capable of retrieving relative changes in hemoglobin concentration from the visible light spectrum. The model is capable of accounting for concentration changes in the nonhemoglobin chromophores and is first characterized with theoretical spectra and liquid phantoms. The model is then used in comparison with a common LIR analysis on temporal measurements from blanched and reddened human skin.
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Affiliation(s)
- Diana L Glennie
- McMaster University, Department of Medical Physics and Applied Radiation Sciences, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada
| | - Joseph E Hayward
- McMaster University, Department of Medical Physics and Applied Radiation Sciences, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, CanadabJuravinski Cancer Centre, Department of Medical Physics, 699 Concession Street, Hamilton, Ontario, L8V 5C2, Canada
| | - Thomas J Farrell
- McMaster University, Department of Medical Physics and Applied Radiation Sciences, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, CanadabJuravinski Cancer Centre, Department of Medical Physics, 699 Concession Street, Hamilton, Ontario, L8V 5C2, Canada
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27
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Xie H, Svenmarker P, Axelsson J, Gräfe S, Kyriazi M, Bendsoe N, Andersson-Engels S, Svanberg K. Pharmacokinetic and biodistribution study following systemic administration of Fospeg®--a Pegylated liposomal mTHPC formulation in a murine model. JOURNAL OF BIOPHOTONICS 2015; 8:142-152. [PMID: 24375973 DOI: 10.1002/jbio.201300133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/01/2013] [Accepted: 11/15/2013] [Indexed: 06/03/2023]
Abstract
Fospeg® is a newly developed photosensitizer formulation based on meso-tetra(hydroxyphenyl)chlorin (mTHPC), with hydrophilic liposomes to carry the hydrophobic photosensitizer to the target tissue. In this study the pharmacokinetics and biodistribution of Fospeg® were investigated by high performance liquid chromatography at various times (0.5-18 hours) following systemic i.v. administration. As a model an experimental HT29 colon tumor in NMRI nu/nu mice was employed. Our study indicates a higher plasma peak concentration, a longer circulation time and a better tumor-to-skin ratio than those of Foslip®, another liposomal mTHPC formulation. Data from ex vivo tissue fluorescence and reflectance imaging exhibit good correlation with chemical extraction. Our results have shown that optical imaging provides the potential for fluorophore quantification in biological tissues.
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Affiliation(s)
- Haiyan Xie
- Department of Physics, Lund University, P.O. Box 118, 22100, Lund, Sweden.
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28
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Yoshida K, Nishidate I. Rapid calculation of diffuse reflectance from a multilayered model by combination of the white Monte Carlo and adding-doubling methods. BIOMEDICAL OPTICS EXPRESS 2014; 5:3901-20. [PMID: 25426319 PMCID: PMC4242026 DOI: 10.1364/boe.5.003901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/08/2014] [Accepted: 10/09/2014] [Indexed: 05/13/2023]
Abstract
To rapidly derive a result for diffuse reflectance from a multilayered model that is equivalent to that of a Monte-Carlo simulation (MCS), we propose a combination of a layered white MCS and the adding-doubling method. For slabs with various scattering coefficients assuming a certain anisotropy factor and without absorption, we calculate the transition matrices for light flow with respect to the incident and exit angles. From this series of precalculated transition matrices, we can calculate the transition matrices for the multilayered model with the specific anisotropy factor. The relative errors of the results of this method compared to a conventional MCS were less than 1%. We successfully used this method to estimate the chromophore concentration from the reflectance spectrum of a numerical model of skin and in vivo human skin tissue.
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29
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Spinelli L, Botwicz M, Zolek N, Kacprzak M, Milej D, Sawosz P, Liebert A, Weigel U, Durduran T, Foschum F, Kienle A, Baribeau F, Leclair S, Bouchard JP, Noiseux I, Gallant P, Mermut O, Farina A, Pifferi A, Torricelli A, Cubeddu R, Ho HC, Mazurenka M, Wabnitz H, Klauenberg K, Bodnar O, Elster C, Bénazech-Lavoué M, Bérubé-Lauzière Y, Lesage F, Khoptyar D, Subash AA, Andersson-Engels S, Di Ninni P, Martelli F, Zaccanti G. Determination of reference values for optical properties of liquid phantoms based on Intralipid and India ink. BIOMEDICAL OPTICS EXPRESS 2014; 5:2037-53. [PMID: 25071947 PMCID: PMC4102347 DOI: 10.1364/boe.5.002037] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/23/2014] [Accepted: 05/25/2014] [Indexed: 05/18/2023]
Abstract
A multi-center study has been set up to accurately characterize the optical properties of diffusive liquid phantoms based on Intralipid and India ink at near-infrared (NIR) wavelengths. Nine research laboratories from six countries adopting different measurement techniques, instrumental set-ups, and data analysis methods determined at their best the optical properties and relative uncertainties of diffusive dilutions prepared with common samples of the two compounds. By exploiting a suitable statistical model, comprehensive reference values at three NIR wavelengths for the intrinsic absorption coefficient of India ink and the intrinsic reduced scattering coefficient of Intralipid-20% were determined with an uncertainty of about 2% or better, depending on the wavelength considered, and 1%, respectively. Even if in this study we focused on particular batches of India ink and Intralipid, the reference values determined here represent a solid and useful starting point for preparing diffusive liquid phantoms with accurately defined optical properties. Furthermore, due to the ready availability, low cost, long-term stability and batch-to-batch reproducibility of these compounds, they provide a unique fundamental tool for the calibration and performance assessment of diffuse optical spectroscopy instrumentation intended to be used in laboratory or clinical environment. Finally, the collaborative work presented here demonstrates that the accuracy level attained in this work for optical properties of diffusive phantoms is reliable.
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Affiliation(s)
- L. Spinelli
- Consiglio Nazionale delle Ricerche–Istituto di Fotonica e Nanotecnologie, Milano,
Italy
| | - M. Botwicz
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - N. Zolek
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - M. Kacprzak
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - D. Milej
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - P. Sawosz
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - A. Liebert
- IBIB, Nalecz Instutute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - U. Weigel
- ICFO, Institut de Ciències Fotòniques, Parc Mediterrani de la Tecnologia, Castelldefels,
Spain
| | - T. Durduran
- ICFO, Institut de Ciències Fotòniques, Parc Mediterrani de la Tecnologia, Castelldefels,
Spain
| | - F. Foschum
- ILM, Institut für Lasertechnologien in der Medizin und Messtechnik an der Universität Ulm,
Germany
| | - A. Kienle
- ILM, Institut für Lasertechnologien in der Medizin und Messtechnik an der Universität Ulm,
Germany
| | - F. Baribeau
- INO, National Optics Institute, Québec,
Canada
| | - S. Leclair
- INO, National Optics Institute, Québec,
Canada
| | | | - I. Noiseux
- INO, National Optics Institute, Québec,
Canada
| | - P. Gallant
- INO, National Optics Institute, Québec,
Canada
| | - O. Mermut
- INO, National Optics Institute, Québec,
Canada
| | - A. Farina
- Consiglio Nazionale delle Ricerche–Istituto di Fotonica e Nanotecnologie, Milano,
Italy
| | - A. Pifferi
- Consiglio Nazionale delle Ricerche–Istituto di Fotonica e Nanotecnologie, Milano,
Italy
- POLIMI, Politecnico di Milano–Dipartimento di Fisica, Milano,
Italy
| | - A. Torricelli
- POLIMI, Politecnico di Milano–Dipartimento di Fisica, Milano,
Italy
| | - R. Cubeddu
- Consiglio Nazionale delle Ricerche–Istituto di Fotonica e Nanotecnologie, Milano,
Italy
- POLIMI, Politecnico di Milano–Dipartimento di Fisica, Milano,
Italy
| | - H.-C. Ho
- ITRI, Industrial Technology Research Institute, Hsinchu, Taiwan
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - M. Mazurenka
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - H. Wabnitz
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - K. Klauenberg
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - O. Bodnar
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - C. Elster
- PTB, Physikalisch-Technische Bundesanstalt, Braunschweig und Berlin,
Germany
| | - M. Bénazech-Lavoué
- TomOptUS, Département de génieélectrique, Université de Sherbrooke,
Canada
| | - Y. Bérubé-Lauzière
- TomOptUS, Département de génieélectrique, Université de Sherbrooke,
Canada
| | - F. Lesage
- Département de génieélectrique, École Polytechnique de Montréal,
Canada
| | - D. Khoptyar
- ULUND, Department of Physics, Lund University,
Sweden
| | - A. A. Subash
- ULUND, Department of Physics, Lund University,
Sweden
| | | | - P. Di Ninni
- UNIFI, Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze,
Italy
| | - F. Martelli
- UNIFI, Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze,
Italy
| | - G. Zaccanti
- UNIFI, Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze,
Italy
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30
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Xie H, Xie Z, Mousavi M, Bendsoe N, Brydegaard M, Axelsson J, Andersson-Engels S. Design and validation of a fiber optic point probe instrument for therapy guidance and monitoring. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:71408. [PMID: 24623193 DOI: 10.1117/1.jbo.19.7.071408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 02/11/2014] [Indexed: 05/21/2023]
Abstract
Optical techniques for tissue diagnostics currently are experiencing tremendous growth in biomedical applications, mainly due to their noninvasive, inexpensive, and real-time functionality. Here, we demonstrate a hand-held fiber optic probe instrument based on fluorescence/reflectance spectroscopy for precise tumor delineation. It is mainly aimed for brain tumor resection guidance with clinical adaptation to minimize the disruption of the standard surgical workflow and is meant as a complement to the state-of-the-art fluorescence surgical microscopy technique. Multiple light sources with fast pulse modulation and detection enable precise quantification of protoporphyrin IX (PpIX), tissue optical properties, and ambient light suppression. Laboratory measurements show the system is insensitive to strong ambient light. Validation measurements of tissue phantoms using nonlinear least squares support vector machines (LS-SVM) regression analysis demonstrate an error of <5% for PpIX concentration ranging from 400 to 1000 nM, even in the presence of large variations in phantom optical properties. The mean error is 3% for reduced scattering coefficient and 5% for blood concentration. Diagnostic precision of 100% was obtained by LS-SVM classification for in vivo skin tumors with topically applied 5-aminolevulinic acid during photodynamic therapy. The probe could easily be generalized to other tissue types and fluorophores for therapy guidance and monitoring.
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Affiliation(s)
- Haiyan Xie
- Lund University, Department of Physics, P.O. Box 118, SE-221 00 Lund, Sweden
| | - Zhiyuan Xie
- Lund University, Department of Physics, P.O. Box 118, SE-221 00 Lund, Sweden
| | | | - Niels Bendsoe
- Skåne University Hospital, Department of Dermatology and Venereology, Lasarettsgatan 15, SE-221 85 Lund, Sweden
| | - Mikkel Brydegaard
- Lund University, Department of Physics, P.O. Box 118, SE-221 00 Lund, Sweden
| | - Johan Axelsson
- Lund University, Department of Physics, P.O. Box 118, SE-221 00 Lund, Sweden
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31
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Selb J, Ogden TM, Dubb J, Fang Q, Boas DA. Comparison of a layered slab and an atlas head model for Monte Carlo fitting of time-domain near-infrared spectroscopy data of the adult head. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:16010. [PMID: 24407503 PMCID: PMC3886581 DOI: 10.1117/1.jbo.19.1.016010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/11/2013] [Accepted: 12/13/2013] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy (NIRS) estimations of the adult brain baseline optical properties based on a homogeneous model of the head are known to introduce significant contamination from extracerebral layers. More complex models have been proposed and occasionally applied to in vivo data, but their performances have never been characterized on realistic head structures. Here we implement a flexible fitting routine of time-domain NIRS data using graphics processing unit based Monte Carlo simulations. We compare the results for two different geometries: a two-layer slab with variable thickness of the first layer and a template atlas head registered to the subject's head surface. We characterize the performance of the Monte Carlo approaches for fitting the optical properties from simulated time-resolved data of the adult head. We show that both geometries provide better results than the commonly used homogeneous model, and we quantify the improvement in terms of accuracy, linearity, and cross-talk from extracerebral layers.
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Affiliation(s)
- Juliette Selb
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
- Address all correspondence to: Juliette Selb, E-mail:
| | - Tyler M. Ogden
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - Jay Dubb
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - Qianqian Fang
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
| | - David A. Boas
- Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Optics Division, Building 149, 13th Street, Charlestown, Massachusetts 02129
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32
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Yang O, Choi B. Accelerated rescaling of single Monte Carlo simulation runs with the Graphics Processing Unit (GPU). BIOMEDICAL OPTICS EXPRESS 2013; 4:2667-72. [PMID: 24298424 PMCID: PMC3829559 DOI: 10.1364/boe.4.002667] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/14/2013] [Accepted: 10/18/2013] [Indexed: 05/25/2023]
Abstract
To interpret fiber-based and camera-based measurements of remitted light from biological tissues, researchers typically use analytical models, such as the diffusion approximation to light transport theory, or stochastic models, such as Monte Carlo modeling. To achieve rapid (ideally real-time) measurement of tissue optical properties, especially in clinical situations, there is a critical need to accelerate Monte Carlo simulation runs. In this manuscript, we report on our approach using the Graphics Processing Unit (GPU) to accelerate rescaling of single Monte Carlo runs to calculate rapidly diffuse reflectance values for different sets of tissue optical properties. We selected MATLAB to enable non-specialists in C and CUDA-based programming to use the generated open-source code. We developed a software package with four abstraction layers. To calculate a set of diffuse reflectance values from a simulated tissue with homogeneous optical properties, our rescaling GPU-based approach achieves a reduction in computation time of several orders of magnitude as compared to other GPU-based approaches. Specifically, our GPU-based approach generated a diffuse reflectance value in 0.08ms. The transfer time from CPU to GPU memory currently is a limiting factor with GPU-based calculations. However, for calculation of multiple diffuse reflectance values, our GPU-based approach still can lead to processing that is ~3400 times faster than other GPU-based approaches.
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Affiliation(s)
- Owen Yang
- Department of Biomedical Engineering, University of California, Irvine, 3120 Natural Sciences II, Irvine, CA 92697-2715, (949) 824-9196, Fax: 949-824-8413 USA
- Beckman Laser Institute and Medical Clinic, Department of Surgery, University of California, Irvine, 1002 Health Sciences Rd., Irvine, CA 92612, Tel: 949-824-9491, Fax: 949-824-6969 USA
| | - Bernard Choi
- Department of Biomedical Engineering, University of California, Irvine, 3120 Natural Sciences II, Irvine, CA 92697-2715, (949) 824-9196, Fax: 949-824-8413 USA
- Beckman Laser Institute and Medical Clinic, Department of Surgery, University of California, Irvine, 1002 Health Sciences Rd., Irvine, CA 92612, Tel: 949-824-9491, Fax: 949-824-6969 USA
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33
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Khoptyar D, Subash AA, Johansson S, Saleem M, Sparén A, Johansson J, Andersson-Engels S. Broadband photon time-of-flight spectroscopy of pharmaceuticals and highly scattering plastics in the VIS and close NIR spectral ranges. OPTICS EXPRESS 2013; 21:20941-53. [PMID: 24103967 DOI: 10.1364/oe.21.020941] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We present extended spectroscopic analysis of pharmaceutical tablets in the close near infrared spectral range performed using broadband photon time-of-flight (PTOF) absorption and scattering spectra measurements. We show that the absorption spectra can be used to perform evaluation of the chemical composition of pharmaceutical tablets without need for chemo-metric calibration. The spectroscopic analysis was performed using an advanced PTOF spectrometer operating in the 650 to 1400 nm spectral range. By employing temporal stabilization of the system we achieve the high precision of 0.5% required to evaluate the concentration of tablet ingredients. In order to further illustrate the performance of the system, we present the first ever reported broadband evaluation of absorption and scattering spectra from pure and doped Spectralon®.
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34
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Zhan Q, He S, Qian J, Cheng H, Cai F. Optimization of optical excitation of upconversion nanoparticles for rapid microscopy and deeper tissue imaging with higher quantum yield. Theranostics 2013; 3:306-16. [PMID: 23650478 PMCID: PMC3645057 DOI: 10.7150/thno.6007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/27/2013] [Indexed: 12/04/2022] Open
Abstract
Relatively low quantum yield (QY), time-consuming scanning and strong absorption of light in tissue are some of the issues present in the development of upconversion nanoparticles (UCNPs) for biomedical applications. In this paper we systematically optimize several aspects of optical excitation of UCNPs to improve their applicability in bioimaging and biotherapy. A novel multi-photon evanescent wave (EW) excitation modality is proposed for UCNP-based microscopy. The scanning-free, ultrahigh contrast and high spatiotemporal resolution method could simultaneously track a few particles in a large area with a speed of ³⁺up to 350 frames per second. The HeLa cancer cell membrane imaging was successfully performed using NaYF₄: 20% Yb³⁺/2Er³⁺ targeting nanoparticles. Studies with different tissues were made to illustrate the impact of optical property parameters on the deep imaging ability of 920-nm band excitation. In the experiments a semiconductor laser with a 920 nm wavelength was used to excite UCNPs in tissue phantom at five depths. Our experimental and computational results have shown that in UCNP-based diffusion optical imaging with 920-nm laser excitation could lead to larger imaging depth range compared to traditional 974-nm excitation in a wide dynamic range of tissue species. As the QY is power density dependent, a pulsed laser is proposed to improve the QY of UCNPs. This proposal is promising in drastically increasing the imaging depth and efficiency of photodynamic therapy.
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Affiliation(s)
- Qiuqiang Zhan
- 1. ZJU-SCNU Joint Research Center of Photonics, Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), 510006 Guangzhou, P. R. China
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Sailing He
- 1. ZJU-SCNU Joint Research Center of Photonics, Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), 510006 Guangzhou, P. R. China
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
- 3. Department of Electromagnetic Engineering, Royal Institute of Technology, 10044 Stockholm, Sweden
| | - Jun Qian
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Hao Cheng
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
| | - Fuhong Cai
- 2. Centre for Optical and Electromagnetic Research, JORCEP, Zhejiang Provincial Key Laboratory for Sensing Technologies, Zijingang campus, Zhejiang University (ZJU), 310058 Hangzhou, P. R. China
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Svensson T, Savo R, Alerstam E, Vynck K, Burresi M, Wiersma DS. Exploiting breakdown of the similarity relation for diffuse light transport: simultaneous retrieval of scattering anisotropy and diffusion constant. OPTICS LETTERS 2013; 38:437-9. [PMID: 23455094 DOI: 10.1364/ol.38.000437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
As manifested in the similarity relation of diffuse light transport, it is difficult to assess single scattering characteristics from multiply scattered light. We take advantage of the limited validity of the diffusion approximation of light transport and demonstrate, experimentally and numerically, that even deep into the multiple scattering regime, time-resolved detection of transmitted light allows simultaneous assessment of both single scattering anisotropy and scattering mean free path, and therefore also macroscopic parameters like the diffusion constant and the transport mean free path. This is achieved via careful assessment of early light and matching against Monte Carlo simulations of radiative transfer.
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Affiliation(s)
- T Svensson
- European Laboratory for Non-linear Spectroscopy, University of Florence, Via Nello Carrara 1, Sesto Fiorentino 50019, Italy.
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36
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Sassaroli A, Martelli F. Equivalence of four Monte Carlo methods for photon migration in turbid media. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2012. [PMID: 23201658 DOI: 10.1364/josaa.29.002110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In the field of photon migration in turbid media, different Monte Carlo methods are usually employed to solve the radiative transfer equation. We consider four different Monte Carlo methods, widely used in the field of tissue optics, that are based on four different ways to build photons' trajectories. We provide both theoretical arguments and numerical results showing the statistical equivalence of the four methods. In the numerical results we compare the temporal point spread functions calculated by the four methods for a wide range of the optical properties in the slab and semi-infinite medium geometry. The convergence of the methods is also briefly discussed.
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Affiliation(s)
- Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, Medford, Massachusetts 02155, USA.
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37
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Xu CT, Svenmarker P, Andersson-Engels S, Krohn J. Transscleral visible/near-infrared spectroscopy for quantitative assessment of haemoglobin in experimental choroidal tumours. Acta Ophthalmol 2012; 90:350-6. [PMID: 21155981 DOI: 10.1111/j.1755-3768.2010.02037.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To study the feasibility of using transscleral visible/near-infrared spectroscopy (Vis/NIRS) to estimate the content of haemoglobin in choroidal tumour phantoms of ex vivo porcine eyes. METHODS Thirty enucleated porcine eyes were prepared with a tumour phantom made by injecting a suspension of gelatine, titanium dioxide and human blood into the suprachoroidal space. The blood concentrations used were 2.5%, 25% and 50%, with 10 eyes in each group. Alternating Vis/NIRS measurements were taken over the phantom inclusion and on the opposite (normal) side of each eye. For statistical analysis, a genetic algorithm was utilized to suppress insignificant wavelengths in the spectra. The processed spectra were then used to build a regression model based on partial least squares regression and evaluated by twofold cross-validation. RESULTS Ultrasonography revealed that all phantoms were localized within the suprachoroidal space with no penetration through the retina. The largest mean diameters of the phantoms with 2.5%, 25% and 50% blood were 15.5, 15.2 and 15.7 mm, respectively (p > 0.05). The largest mean thicknesses were 4.5, 4.5 and 4.8 mm, respectively (p > 0.05). Statistical analysis of the spectral data showed that it was possible to correctly discriminate between the normal side and the tumour phantom side of the eyes in 99.88% of cases. The phantoms could be correctly classified according to their blood concentrations in 99.42% of cases. CONCLUSIONS This study demonstrates that transscleral Vis/NIRS is a feasible and accurate method for the detection of choroidal tumours and to assess the haemoglobin content in such lesions.
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Affiliation(s)
- Can T Xu
- Department of Physics, Lund University, Lund, Sweden
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38
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Fredriksson I, Larsson M, Strömberg T. Inverse Monte Carlo method in a multilayered tissue model for diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:047004. [PMID: 22559695 DOI: 10.1117/1.jbo.17.4.047004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Model based data analysis of diffuse reflectance spectroscopy data enables the estimation of optical and structural tissue parameters. The aim of this study was to present an inverse Monte Carlo method based on spectra from two source-detector distances (0.4 and 1.2 mm), using a multilayered tissue model. The tissue model variables include geometrical properties, light scattering properties, tissue chromophores such as melanin and hemoglobin, oxygen saturation and average vessel diameter. The method utilizes a small set of presimulated Monte Carlo data for combinations of different levels of epidermal thickness and tissue scattering. The path length distributions in the different layers are stored and the effect of the other parameters is added in the post-processing. The accuracy of the method was evaluated using Monte Carlo simulations of tissue-like models containing discrete blood vessels, evaluating blood tissue fraction and oxygenation. It was also compared to a homogeneous model. The multilayer model performed better than the homogeneous model and all tissue parameters significantly improved spectral fitting. Recorded in vivo spectra were fitted well at both distances, which we previously found was not possible with a homogeneous model. No absolute intensity calibration is needed and the algorithm is fast enough for real-time processing.
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Affiliation(s)
- Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, University Hospital, 581 85 Linköping, Sweden.
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39
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Chuang CC, Lee CY, Chen CM, Hsieh YS, Liu TC, Sun CW. Diffuser-aided diffuse optical imaging for breast tumor: a feasibility study based on time-resolved three-dimensional Monte Carlo modeling. IEEE Trans Biomed Eng 2012; 59:1454-61. [PMID: 22394571 DOI: 10.1109/tbme.2012.2187900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This study proposed diffuser-aided diffuse optical imaging (DADOI) as a new approach to improve the performance of the conventional diffuse optical tomography (DOT) approach for breast imaging. The 3-D breast model for Monte Carlo simulation is remodeled from clinical MRI image. The modified Beer-Lambert's law is adopted with the DADOI approach to substitute the complex algorithms of inverse problem for mapping of spatial distribution, and the depth information is obtained based on the time-of-flight estimation. The simulation results demonstrate that the time-resolved Monte Carlo method can be capable of performing source-detector separations analysis. The dynamics of photon migration with various source-detector separations are analyzed for the characterization of breast tissue and estimation of optode arrangement. The source-detector separations should be less than 4 cm for breast imaging in DOT system. Meanwhile, the feasibility of DADOI was manifested in this study. In the results, DADOI approach can provide better imaging contrast and faster imaging than conventional DOT measurement. The DADOI approach possesses great potential to detect the breast tumor in early stage and chemotherapy monitoring that implies a good feasibility for clinical application.
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Affiliation(s)
- Ching-Cheng Chuang
- Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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40
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Chen J, Intes X. Comparison of Monte Carlo methods for fluorescence molecular tomography-computational efficiency. Med Phys 2011; 38:5788-98. [PMID: 21992393 DOI: 10.1118/1.3641827] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The Monte Carlo method is an accurate model for time-resolved quantitative fluorescence tomography. However, this method suffers from low computational efficiency due to the large number of photons required for reliable statistics. This paper presents a comparison study on the computational efficiency of three Monte Carlo-based methods for time-domain fluorescence molecular tomography. METHODS The methods investigated to generate time-gated Jacobians were the perturbation Monte Carlo (pMC) method, the adjoint Monte Carlo (aMC) method and the mid-way Monte Carlo (mMC) method. The effects of the different parameters that affect the computation time and statistics reliability were evaluated. Also, the methods were applied to a set of experimental data for tomographic application. RESULTS In silico results establish that, the investigated parameters affect the computational time for the three methods differently (linearly, quadratically, or not significantly). Moreover, the noise level of the Jacobian varies when these parameters change. The experimental results in preclinical settings demonstrates the feasibility of using both aMC and pMC methods for time-resolved whole body studies in small animals within a few hours. CONCLUSIONS Among the three Monte Carlo methods, the mMC method is a computationally prohibitive technique that is not well suited for time-domain fluorescence tomography applications. The pMC method is advantageous over the aMC method when the early gates are employed and large number of detectors is present. Alternatively, the aMC method is the method of choice when a small number of source-detector pairs are used.
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Affiliation(s)
- Jin Chen
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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41
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Pogue BW, Davis SC, Leblond F, Mastanduno MA, Dehghani H, Paulsen KD. Implicit and explicit prior information in near-infrared spectral imaging: accuracy, quantification and diagnostic value. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4531-57. [PMID: 22006905 PMCID: PMC3263784 DOI: 10.1098/rsta.2011.0228] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Near-infrared spectroscopy (NIRS) of tissue provides quantification of absorbers, scattering and luminescent agents in bulk tissue through the use of measurement data and assumptions. Prior knowledge can be critical about things such as (i) the tissue shape and/or structure, (ii) spectral constituents, (iii) limits on parameters, (iv) demographic or biomarker data, and (v) biophysical models of the temporal signal shapes. A general framework of NIRS imaging with prior information is presented, showing that prior information datasets could be incorporated at any step in the NIRS process, with the general workflow being: (i) data acquisition, (ii) pre-processing, (iii) forward model, (iv) inversion/reconstruction, (v) post-processing, and (vi) interpretation/diagnosis. Most of the development in NIRS has used ad hoc or empirical implementations of prior information such as pre-measured absorber or fluorophore spectra, or tissue shapes as estimated by additional imaging tools. A comprehensive analysis would examine what prior information maximizes the accuracy in recovery and value for medical diagnosis, when implemented at separate stages of the NIRS sequence. Individual applications of prior information can show increases in accuracy or improved ability to estimate biochemical features of tissue, while other approaches may not. Most beneficial inclusion of prior information has been in the inversion/reconstruction process, because it solves the mathematical intractability. However, it is not clear that this is always the most beneficial stage.
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Affiliation(s)
- Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
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42
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Martinelli M, Gardner A, Cuccia D, Hayakawa C, Spanier J, Venugopalan V. Analysis of single Monte Carlo methods for prediction of reflectance from turbid media. OPTICS EXPRESS 2011; 19:19627-42. [PMID: 21996904 PMCID: PMC3347703 DOI: 10.1364/oe.19.019627] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Starting from the radiative transport equation we derive the scaling relationships that enable a single Monte Carlo (MC) simulation to predict the spatially- and temporally-resolved reflectance from homogeneous semi-infinite media with arbitrary scattering and absorption coefficients. This derivation shows that a rigorous application of this single Monte Carlo (sMC) approach requires the rescaling to be done individually for each photon biography. We examine the accuracy of the sMC method when processing simulations on an individual photon basis and also demonstrate the use of adaptive binning and interpolation using non-uniform rational B-splines (NURBS) to achieve order of magnitude reductions in the relative error as compared to the use of uniform binning and linear interpolation. This improved implementation for sMC simulation serves as a fast and accurate solver to address both forward and inverse problems and is available for use at http://www.virtualphotonics.org/.
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Affiliation(s)
- Michele Martinelli
- Dipartimento di Fisica, Politecnico di Milano, Milan, 20133,
Italy
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA 92697-2575,
USA
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, CA 92697-3010,
USA
| | - Adam Gardner
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA 92697-2575,
USA
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, CA 92697-3010,
USA
| | - David Cuccia
- Modulated Imaging, Inc., 1002 Health Sciences Road, Irvine, CA 92612,
USA
| | - Carole Hayakawa
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA 92697-2575,
USA
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, CA 92697-3010,
USA
| | - Jerome Spanier
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, CA 92697-3010,
USA
| | - Vasan Venugopalan
- Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, CA 92697-2575,
USA
- Laser Microbeam and Medical Program, Beckman Laser Institute, University of California, Irvine, Irvine, CA 92697-3010,
USA
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Tseng SH, Hou MF. Efficient determination of the epidermal optical properties using a diffusion model-based approach: Monte Carlo studies. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:087007. [PMID: 21895334 DOI: 10.1117/1.3609821] [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
In our previous studies, we have shown that the diffusing probe geometry can be used in conjunction with a two-layer diffusion model to accurately recover the absorption and scattering properties of skin in vivo. By modifying the original design to the diffusing probe with planar source (DPPS) geometry, we have also demonstrated that the efficiency of the accompanying multilayer diffusion model is comparable to that of a standard semi-infinite diffusion model; thus, precise quantification of superficial tissue optical properties in real time using a diffusion model becomes possible. In this study, the performance of the DPPS diffusion model is evaluated using Monte Carlo simulations and phantom measurements. It is found that the DPPS geometry is advantageous over the conventional planar source illumination geometry in interrogating superficial volumes of samples. In addition, our simulation results have shown that the DPPS geometry is capable of accurately recovering the optical properties of 50-μm thick epidermis and could be very useful in detecting cutaneous melanoma that has a radius as small as 250 μm.
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Affiliation(s)
- Sheng-Hao Tseng
- National Cheng-Kung University, Department of Photonics, Tainan 701, Taiwan.
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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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45
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Chen P, Fernald B, Lin W. Estimation of regional hemoglobin concentration in biological tissues using diffuse reflectance spectroscopy with a novel spectral interpretation algorithm. Phys Med Biol 2011; 56:3985-4000. [DOI: 10.1088/0031-9155/56/13/015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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46
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Xie H, Liu H, Svenmarker P, Axelsson J, Xu CT, Gräfe S, Lundeman JH, Cheng HPH, Svanberg S, Bendsoe N, Andersen PE, Svanberg K, Andersson-Engels S. Drug quantification in turbid media by fluorescence imaging combined with light-absorption correction using white Monte Carlo simulations. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:066002. [PMID: 21721803 DOI: 10.1117/1.3585675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Accurate quantification of photosensitizers is in many cases a critical issue in photodynamic therapy. As a noninvasive and sensitive tool, fluorescence imaging has attracted particular interest for quantification in pre-clinical research. However, due to the absorption of excitation and emission light by turbid media, such as biological tissue, the detected fluorescence signal does not have a simple and unique dependence on the fluorophore concentration for different tissues, but depends in a complex way on other parameters as well. For this reason, little has been done on drug quantification in vivo by the fluorescence imaging technique. In this paper we present a novel approach to compensate for the light absorption in homogeneous turbid media both for the excitation and emission light, utilizing time-resolved fluorescence white Monte Carlo simulations combined with the Beer-Lambert law. This method shows that the corrected fluorescence intensity is almost proportional to the absolute fluorophore concentration. The results on controllable tissue phantoms and murine tissues are presented and show good correlations between the evaluated fluorescence intensities after the light-absorption correction and absolute fluorophore concentrations. These results suggest that the technique potentially provides the means to quantify the fluorophore concentration from fluorescence images.
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Affiliation(s)
- Haiyan Xie
- Lund University, Department of Physics, P.O. Box 118, SE-221 00, Lund, Sweden.
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Chen PC, Lin WC. Spectral-profile-based algorithm for hemoglobin oxygen saturation determination from diffuse reflectance spectra. BIOMEDICAL OPTICS EXPRESS 2011; 2:1082-96. [PMID: 21559121 PMCID: PMC3087566 DOI: 10.1364/boe.2.001082] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 03/29/2011] [Accepted: 04/01/2011] [Indexed: 05/26/2023]
Abstract
Variations of hemoglobin (Hb) oxygenation in tissue provide important indications concerning the physiological conditions of tissue, and the data related to these variations are of intense interest in medical research as well as in clinical care. In this study, we derived a new algorithm to estimate Hb oxygenation from diffuse reflectance spectra. The algorithm was developed based on the unique spectral profile differences between the extinction coefficient spectra of oxy-Hb and deoxy-Hb within the visible wavelength region. Using differential wavelet transformation, these differences were quantified using the locations of certain spectral features, and, then, they were related to the oxygenation saturation level of Hb. The applicability of the algorithm was evaluated using a set of diffuse reflectance spectra produced by a Monte Carlo simulation model of photon migration and by tissue phantoms experimentally. The algorithm was further applied to the diffuse reflectance spectra acquired from in vivo experiments to demonstrate its clinical utility. The validation and evaluation results concluded that the algorithm is applicable to various tissue types (i.e., scattering properties) and can be easily used in conjunction with a diverse range of probe geometries for real-time monitoring of Hb oxygenation.
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Affiliation(s)
- Po-Ching Chen
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EAS 2673, Miami, Florida 33176, USA
| | - Wei-Chiang Lin
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EAS 2673, Miami, Florida 33176, USA
- Brain Institute, Miami Children’s Hospital, 3100 SW 62 Ave, Miami, FL 33155, USA
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48
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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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Moore CM, Mosse CA, Allen C, Payne H, Emberton M, Bown SG. Light penetration in the human prostate: a whole prostate clinical study at 763 nm. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:015003. [PMID: 21280905 DOI: 10.1117/1.3528638] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Photodynamic therapy (PDT) is being investigated as a treatment for localized prostate cancer. Photodynamic therapy uses a photosensitizing drug which is activated by a specific wavelength of light, in the presence of oxygen. The activated drug reacts with tissue oxygen to produce reactive oxygen species which are responsible for localized tissue necrosis. One of the determinants of the PDT effect is the penetration of light in the prostate. This study assesses the penetration depth of 763 nm light throughout the prostate. Eight men undergoing multiple hollow needle insertion for high dose rate brachytherapy were recruited. 763 nm light, produced by a diode laser, was delivered to the prostate using cylindrically diffusing optical fibers within the plastic needles. Light was detected at different distances from the source, using an isotropic detector within nearby needles. Penetration depth was calculated using the Boltzmann approximation to the diffusion equation. Delivery detector fiber separation was measured on computed tomography. The mean penetration depth was 0.57 cm, but there was within patient variation of a mean factor of 4.3. Further work is ongoing to assess the effect of such variability in light penetration, on the PDT effect.
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Affiliation(s)
- Caroline M Moore
- National Medical Laser Centre, University College London, Department of Urology, University College London Hospitals Trust, London, NW1 2PG, United Kingdom.
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50
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Diop M, Tichauer KM, Elliott JT, Migueis M, Lee TY, St Lawrence K. Comparison of time-resolved and continuous-wave near-infrared techniques for measuring cerebral blood flow in piglets. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:057004. [PMID: 21054120 DOI: 10.1117/1.3488626] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A primary focus of neurointensive care is monitoring the injured brain to detect harmful events that can impair cerebral blood flow (CBF), resulting in further injury. Since current noninvasive methods used in the clinic can only assess blood flow indirectly, the goal of this research is to develop an optical technique for measuring absolute CBF. A time-resolved near-infrared (TR-NIR) apparatus is built and CBF is determined by a bolus-tracking method using indocyanine green as an intravascular flow tracer. As a first step in the validation of this technique, CBF is measured in newborn piglets to avoid signal contamination from extracerebral tissue. Measurements are acquired under three conditions: normocapnia, hypercapnia, and following carotid occlusion. For comparison, CBF is concurrently measured by a previously developed continuous-wave NIR method. A strong correlation between CBF measurements from the two techniques is revealed with a slope of 0.79±0.06, an intercept of -2.2±2.5 ml∕100 g∕min, and an R2 of 0.810±0.088. Results demonstrate that TR-NIR can measure CBF with reasonable accuracy and is sensitive to flow changes. The discrepancy between the two methods at higher CBF could be caused by differences in depth sensitivities between continuous-wave and time-resolved measurements.
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Affiliation(s)
- Mamadou Diop
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada N6A 4V2.
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