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Giacalone G, Zanoletti M, Contini D, Re R, Spinelli L, Roveri L, Torricelli A. Cerebral time domain-NIRS: reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects. BIOMEDICAL OPTICS EXPRESS 2017; 8:4987-5000. [PMID: 29188096 PMCID: PMC5695946 DOI: 10.1364/boe.8.004987] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/14/2017] [Accepted: 09/22/2017] [Indexed: 05/20/2023]
Abstract
The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO2) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted with the diffusion model for semi-infinite homogenous media. Reproducibility, performed on 3 measurements at 5 minutes intervals, ranges from 1.8 to 6.9% for each of the hemoglobin species. The mean ± SD global values of HbR, HbO, HbT, StO2 are respectively 24 ± 7 μM, 33.3 ± 9.5 μM, 57.4 ± 15.8 μM, 58 ± 4.2%. StO2 displays the narrowest range of variability across brain regions.
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Affiliation(s)
- Giacomo Giacalone
- San Raffaele Scientific Institute, Neurology Department, Via Olgettina 60, 20132, Milan, Italy
- University “Vita-Salute” San Raffaele, Via Olgettina 60, 20132, Milan, Italy
| | - Marta Zanoletti
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Rebecca Re
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Luisa Roveri
- San Raffaele Scientific Institute, Neurology Department, Via Olgettina 60, 20132, Milan, Italy
- University “Vita-Salute” San Raffaele, Via Olgettina 60, 20132, Milan, Italy
- These authors contributed equally to this paper
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
- These authors contributed equally to this paper
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52
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Zouaoui J, Di Sieno L, Hervé L, Pifferi A, Farina A, Mora AD, Derouard J, Dinten JM. Chromophore decomposition in multispectral time-resolved diffuse optical tomography. BIOMEDICAL OPTICS EXPRESS 2017; 8:4772-4787. [PMID: 29082101 PMCID: PMC5654816 DOI: 10.1364/boe.8.004772] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/10/2017] [Accepted: 08/31/2017] [Indexed: 05/04/2023]
Abstract
Multicomponent phantom measurements are carried out to evaluate the ability of multispectral time domain diffuse optical tomography in reflectance geometry to quantify the position and the composition of small heterogeneities at depths of 1-1.5 cm in turbid media. Time-resolved data were analyzed with the Mellin-Laplace transform. Results show good localization and correct composition gradation of objects but still a lack of absolute material composition accuracy when no a priori geometry information is known.
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Affiliation(s)
- Judy Zouaoui
- Univ. Grenoble Alpes, F-38000 Grenoble, France, CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - Laura Di Sieno
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Lionel Hervé
- Univ. Grenoble Alpes, F-38000 Grenoble, France, CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Alberto Dalla Mora
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | | | - Jean-Marc Dinten
- Univ. Grenoble Alpes, F-38000 Grenoble, France, CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
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Time-Resolved Diffuse Optical Spectroscopy and Imaging Using Solid-State Detectors: Characteristics, Present Status, and Research Challenges. SENSORS 2017; 17:s17092115. [PMID: 28906462 PMCID: PMC5621067 DOI: 10.3390/s17092115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 09/03/2017] [Accepted: 09/06/2017] [Indexed: 02/06/2023]
Abstract
Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are emerging non-invasive imaging modalities that have wide spread potential applications in many fields, particularly for structural and functional imaging in medicine. In this article, we review time-resolved diffuse optical imaging (TR-DOI) systems using solid-state detectors with a special focus on Single-Photon Avalanche Diodes (SPADs) and Silicon Photomultipliers (SiPMs). These TR-DOI systems can be categorized into two types based on the operation mode of the detector (free-running or time-gated). For the TR-DOI prototypes, the physical concepts, main components, figures-of-merit of detectors, and evaluation parameters are described. The performance of TR-DOI prototypes is evaluated according to the parameters used in common protocols to test DOI systems particularly basic instrumental performance (BIP). In addition, the potential features of SPADs and SiPMs to improve TR-DOI systems and expand their applications in the foreseeable future are discussed. Lastly, research challenges and future developments for TR-DOI are discussed for each component in the prototype separately and also for the entire system.
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54
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Di Sieno L, Nissinen J, Hallman L, Martinenghi E, Contini D, Pifferi A, Kostamovaara J, Mora AD. Miniaturized pulsed laser source for time-domain diffuse optics routes to wearable devices. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-9. [PMID: 28823112 DOI: 10.1117/1.jbo.22.8.085004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/27/2017] [Indexed: 05/23/2023]
Abstract
We validate a miniaturized pulsed laser source for use in time-domain (TD) diffuse optics, following rigorous and shared protocols for performance assessment of this class of devices. This compact source (12×6 mm2) has been previously developed for range finding applications and is able to provide short, high energy (∼100 ps, ∼0.5 nJ) optical pulses at up to 1 MHz repetition rate. Here, we start with a basic level laser characterization with an analysis of suitability of this laser for the diffuse optics application. Then, we present a TD optical system using this source and its performances in both recovering optical properties of tissue-mimicking homogeneous phantoms and in detecting localized absorption perturbations. Finally, as a proof of concept of in vivo application, we demonstrate that the system is able to detect hemodynamic changes occurring in the arm of healthy volunteers during a venous occlusion. Squeezing the laser source in a small footprint removes a key technological bottleneck that has hampered so far the realization of a miniaturized TD diffuse optics system, able to compete with already assessed continuous-wave devices in terms of size and cost, but with wider performance potentialities, as demonstrated by research over the last two decades.
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Affiliation(s)
- Laura Di Sieno
- Politecnico di Milano, Dipartimento di Fisica, Milan, Italy
| | - Jan Nissinen
- University of Oulu, Circuits and Systems Research Unit, Oulu, Finland
| | - Lauri Hallman
- University of Oulu, Circuits and Systems Research Unit, Oulu, Finland
| | | | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Milan, Italy
| | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Milan, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Milano, Italy
| | - Juha Kostamovaara
- University of Oulu, Circuits and Systems Research Unit, Oulu, Finland
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Konugolu Venkata Sekar S, Beh JS, Farina A, Dalla Mora A, Pifferi A, Taroni P. Broadband diffuse optical characterization of elastin for biomedical applications. Biophys Chem 2017; 229:130-134. [PMID: 28733103 DOI: 10.1016/j.bpc.2017.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/06/2017] [Accepted: 07/11/2017] [Indexed: 12/21/2022]
Abstract
Elastin is a key structural protein of dynamic connective tissues widely found in the extracellular matrix of skin, arteries, lungs and ligaments. It is responsible for a range of diseases related to aging of biological tissues. The optical characterization of elastin can open new opportunities for its investigation in biomedical studies. In this work, we present the absorption spectra of elastin using a broadband (550-1350nm) diffuse optical spectrometer. Distortions caused by fluorescence and finite bandwidth of the laser source on estimated absorption were effectively accounted for in measurements and data analysis and compensated. A comprehensive summary and comparison between collagen and elastin is presented, highlighting distinct features for its accurate quantification in biological applications.
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Affiliation(s)
| | - Joo Sin Beh
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alberto Dalla Mora
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Antonio Pifferi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Paola Taroni
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy; Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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56
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Re R, Martinenghi E, Mora AD, Contini D, Pifferi A, Torricelli A. Probe-hosted silicon photomultipliers for time-domain functional near-infrared spectroscopy: phantom and in vivo tests. NEUROPHOTONICS 2016; 3:045004. [PMID: 27752520 PMCID: PMC5061109 DOI: 10.1117/1.nph.3.4.045004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/19/2016] [Indexed: 05/23/2023]
Abstract
We report the development of a compact probe for time-domain (TD) functional near-infrared spectroscopy (fNIRS) based on a fast silicon photomultiplier (SiPM) that can be put directly in contact with the sample without the need of optical fibers for light collection. We directly integrated an avalanche signal amplification stage close to the SiPM, thus reducing the size of the detection channel and optimizing the signal immunity to electromagnetic interferences. The whole detection electronics was placed in a plastic screw holder compatible with the electroencephalography standard cap for measurement on brain or with custom probe holders. The SiPM is inserted into a transparent and insulating resin to avoid the direct contact of the scalp with the 100-V bias voltage. The probe was integrated in an instrument for TD fNIRS spectroscopy. The system was characterized on tissue phantoms in terms of temporal resolution, responsivity, linearity, and capability to detect deep absorption changes. Preliminary in vivo tests on adult volunteers were performed to monitor hemodynamic changes in the arm during a cuff occlusion and in the brain cortex during a motor task.
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Affiliation(s)
- Rebecca Re
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Edoardo Martinenghi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Alberto Dalla Mora
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
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57
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Zouaoui J, Di Sieno L, Hervé L, Pifferi A, Farina A, Mora AD, Derouard J, Dinten JM. Quantification in time-domain diffuse optical tomography using Mellin-Laplace transforms. BIOMEDICAL OPTICS EXPRESS 2016; 7:4346-4363. [PMID: 27867736 PMCID: PMC5102524 DOI: 10.1364/boe.7.004346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/14/2016] [Accepted: 08/28/2016] [Indexed: 05/21/2023]
Abstract
Simulations and phantom measurements are used to evaluate the ability of time-domain diffuse optical tomography using Mellin-Laplace transforms to quantify the absorption perturbation of centimetric objects immersed at depth 1-2 cm in turbid media. We find that the estimated absorption coefficient varies almost linearly with the absorption change in the range of 0-0.15 cm-1 but is underestimated by a factor that depends on the inclusion depth (~2, 3 and 6 for depths of 1.0, 1.5 and 2.0 cm respectively). For larger absorption changes, the variation is sublinear with ~20% decrease for δμa = 0.37 cm-1. By contrast, constraining the absorption change to the actual volume of the inclusion may considerably improve the accuracy and linearity of the reconstructed absorption.
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Affiliation(s)
- Judy Zouaoui
- Univ. Grenoble Alpes, F-38000 Grenoble, France CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - Laura Di Sieno
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Lionel Hervé
- Univ. Grenoble Alpes, F-38000 Grenoble, France CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Andrea Farina
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | - Alberto Dalla Mora
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano I-20133, Italy
| | | | - Jean-Marc Dinten
- Univ. Grenoble Alpes, F-38000 Grenoble, France CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
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58
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Pifferi A, Contini D, Mora AD, Farina A, Spinelli L, Torricelli A. New frontiers in time-domain diffuse optics, a review. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:091310. [PMID: 27311627 DOI: 10.1117/1.jbo.21.9.091310] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/24/2016] [Indexed: 05/20/2023]
Abstract
The recent developments in time-domain diffuse optics that rely on physical concepts (e.g., time-gating and null distance) and advanced photonic components (e.g., vertical cavity source-emitting laser as light sources, single photon avalanche diode, and silicon photomultipliers as detectors, fast-gating circuits, and time-to-digital converters for acquisition) are focused. This study shows how these tools could lead on one hand to compact and wearable time-domain devices for point-of-care diagnostics down to the consumer level and on the other hand to powerful systems with exceptional depth penetration and sensitivity.
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Affiliation(s)
- Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milan I-20133, ItalybIstituto di Fotonica e Nanotecnologie, Consiglio Nazionale per le Ricerche, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
| | - Alberto Dalla Mora
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale per le Ricerche, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale per le Ricerche, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milan I-20133, ItalybIstituto di Fotonica e Nanotecnologie, Consiglio Nazionale per le Ricerche, Piazza Leonardo da Vinci 32, Milan I-20133, Italy
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59
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Pifferi A, Torricelli A, Cubeddu R, Quarto G, Re R, Sekar SKV, Spinelli L, Farina A, Martelli F, Wabnitz H. Mechanically switchable solid inhomogeneous phantom for performance tests in diffuse imaging and spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2015. [PMID: 26220211 DOI: 10.1117/1.jbo.20.12.121304] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A mechanically switchable solid inhomogeneous phantom simulating localized absorption changes was developed and characterized. The homogeneous host phantom was made of epoxy resin with black toner and titanium dioxide particles added as absorbing and scattering components, respectively. A cylindrical rod, movable along a hole in the block and made of the same material, has a black polyvinyl chloride cylinder embedded in its center. By varying the volume and position of the black inclusion, absorption perturbations can be generated over a large range of magnitudes. The phantom has been characterized by various time-domain diffuse optics instruments in terms of absorption and scattering spectra, transmittance images, and reflectance contrast. Addressing a major application of the phantom for performance characterization for functional near-infrared spectroscopy of the brain, the contrast was measured in reflectance mode while black cylinders of volumes from ≈20 mm3 to ≈270 mm3 were moved in lateral and depth directions, respectively. The new type of solid inhomogeneous phantom is expected to become a useful tool for routine quality check of clinical instruments or implementation of industrial standards provided an experimental characterization of the phantom is performed in advance.
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Affiliation(s)
- Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Rinaldo Cubeddu
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, ItalybIstituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Giovanna Quarto
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Rebecca Re
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Sanathana K V Sekar
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - Fabrizio Martelli
- Università degli Studi di Firenze, Dipartimento di Fisica e Astronomia, Via G. Sansone 1, Firenze, Sesto Fiorentino 50019, Italy
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, Berlin 10587, Germany
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60
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Krauter P, Nothelfer S, Bodenschatz N, Simon E, Stocker S, Foschum F, Kienle A. Optical phantoms with adjustable subdiffusive scattering parameters. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:105008. [PMID: 26473589 DOI: 10.1117/1.jbo.20.10.105008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/24/2015] [Indexed: 05/03/2023]
Abstract
A new epoxy-resin-based optical phantom system with adjustable subdiffusive scattering parameters is presented along with measurements of the intrinsic absorption, scattering, fluorescence, and refractive index of the matrix material. Both an aluminium oxide powder and a titanium dioxide dispersion were used as scattering agents and we present measurements of their scattering and reduced scattering coefficients. A method is theoretically described for a mixture of both scattering agents to obtain continuously adjustable anisotropy values g between 0.65 and 0.9 and values of the phase function parameter γ in the range of 1.4 to 2.2. Furthermore, we show absorption spectra for a set of pigments that can be added to achieve particular absorption characteristics. By additional analysis of the aging, a fully characterized phantom system is obtained with the novelty of g and γ parameter adjustment.
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61
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Lemaillet P, Bouchard JP, Allen DW. Development of traceable measurement of the diffuse optical properties of solid reference standards for biomedical optics at National Institute of Standards and Technology. APPLIED OPTICS 2015; 54:6118-27. [PMID: 26193162 DOI: 10.1364/ao.54.006118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The development of a national reference instrument dedicated to the measurement of the scattering and absorption properties of solid tissue-mimicking phantoms used as reference standards is presented. The optical properties of the phantoms are measured with a double-integrating sphere setup in the steady-state domain, coupled with an inversion routine of the adding-doubling procedure that allows for the computation of the uncertainty budget for the measurements. The results are compared to the phantom manufacturer's values obtained by a time-resolved approach. The results suggest that the agreement between these two independent methods is within the estimated uncertainties. This new reference instrument will provide optical biomedical research laboratories with reference values for absolute diffuse optical properties of phantom materials.
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62
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Mora AD, Martinenghi E, Contini D, Tosi A, Boso G, Durduran T, Arridge S, Martelli F, Farina A, Torricelli A, Pifferi A. Fast silicon photomultiplier improves signal harvesting and reduces complexity in time-domain diffuse optics. OPTICS EXPRESS 2015; 23:13937-46. [PMID: 26072763 DOI: 10.1364/oe.23.013937] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We present a proof of concept prototype of a time-domain diffuse optics probe exploiting a fast Silicon PhotoMultiplier (SiPM), featuring a timing resolution better than 80 ps, a fast tail with just 90 ps decay time-constant and a wide active area of 1 mm2. The detector is hosted into the probe and used in direct contact with the sample under investigation, thus providing high harvesting efficiency by exploiting the whole SiPM numerical aperture and also reducing complexity by avoiding the use of cumbersome fiber bundles. Our tests also demonstrate high accuracy and linearity in retrieving the optical properties and suitable contrast and depth sensitivity for detecting localized inhomogeneities. In addition to a strong improvement in both instrumentation cost and size with respect to legacy solutions, the setup performances are comparable to those of state-of-the-art time-domain instrumentation, thus opening a new way to compact, low-cost and high-performance time-resolved devices for diffuse optical imaging and spectroscopy.
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63
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Seifert B, Zude M, Spinelli L, Torricelli A. Optical properties of developing pip and stone fruit reveal underlying structural changes. PHYSIOLOGIA PLANTARUM 2015; 153:327-336. [PMID: 24853358 DOI: 10.1111/ppl.12232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 03/18/2014] [Accepted: 04/24/2014] [Indexed: 06/03/2023]
Abstract
Analyzing the optical properties of fruits represents a powerful approach for non-destructive observations of fruit development. With classical spectroscopy in the visible and near-infrared wavelength ranges, the apparent attenuation of light results from its absorption or scattering. In horticultural applications, frequently, the normalized difference vegetation index (NDVI) is employed to reduce the effects of varying scattering properties on the apparent signal. However, this simple approach appears to be limited. In the laboratory, with time-resolved reflectance spectroscopy, the absorption coefficient, μa , and the reduced scattering coefficient, μs ', can be analyzed separately. In this study, these differentiated optical properties were recorded (540-940 nm), probing fruit tissue from the skin up to 2 cm depth in apple (Malus × domestica 'Elstar') and plum (Prunus domestica 'Tophit plus') harvested four times (65-145 days after full bloom). The μa spectra showed typical peak at 670 nm of the chlorophyll absorption. The μs ' at 670 nm in apple changed by 14.7% (18.2-15.5 cm(-1) ), while in plum differences of 41.5% (8.5-5.0 cm(-1) ) were found. The scattering power, the relative change of μs ', was zero in apple, but enhanced in plum over the fruit development period. This mirrors more isotropic and constant structures in apple compared with plum. For horticultural applications, the larger variability in scattering properties of plum explains the discrepancy between commercially assessed NDVI values or similar indices and the absolute μa values in plum (R < 0.05), while the NDVI approach appeared reasonable in apple (R ≥ 0.80).
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Affiliation(s)
- Birgit Seifert
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim, 14469, Potsdam, Germany
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Kolste KK, Kanick SC, Valdés PA, Jermyn M, Wilson BC, Roberts DW, Paulsen KD, Leblond F. Macroscopic optical imaging technique for wide-field estimation of fluorescence depth in optically turbid media for application in brain tumor surgical guidance. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:26002. [PMID: 25652704 PMCID: PMC4405086 DOI: 10.1117/1.jbo.20.2.026002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/05/2015] [Indexed: 05/13/2023]
Abstract
A diffuse imaging method is presented that enables wide-field estimation of the depth of fluorescent molecular markers in turbid media by quantifying the deformation of the detected fluorescence spectra due to the wavelength-dependent light attenuation by overlying tissue. This is achieved by measuring the ratio of the fluorescence at two wavelengths in combination with normalization techniques based on diffuse reflectance measurements to evaluate tissue attenuation variations for different depths. It is demonstrated that fluorescence topography can be achieved up to a 5 mm depth using a near-infrared dye with millimeter depth accuracy in turbid media having optical properties representative of normal brain tissue. Wide-field depth estimates are made using optical technology integrated onto a commercial surgical microscope, making this approach feasible for real-world applications.
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Affiliation(s)
- Kolbein K. Kolste
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Stephen C. Kanick
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Pablo A. Valdés
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
- Dartmouth College, Geisel School of Medicine, Hanover, 1 Rope Ferry Road, New Hampshire 03755, United States
| | - Michael Jermyn
- Polytechnique Montreal, Engineering Physics Department, Montreal, Québec H3C 3A7, Canada
| | - Brian C. Wilson
- University of Toronto, Ontario Cancer Institute, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada
| | - David W. Roberts
- Dartmouth-Hitchcock Medical Center, Section of Neurosurgery, 1 Medical Center Drive, Lebanon, New Hampshire 03756, United States
| | - Keith D. Paulsen
- Dartmouth College, Thayer School of Engineering, Hanover, 14 Engineering Drive, New Hampshire 03755, United States
| | - Frederic Leblond
- Polytechnique Montreal, Engineering Physics Department, Montreal, Québec H3C 3A7, Canada
- Address all correspondence to: Frederic Leblond, E-mail:
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65
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Wu Q, Ren W, Yu Z, Dong E, Zhang S, Xu RX. Microfabrication of polydimethylsiloxane phantoms to simulate tumor hypoxia and vascular anomaly. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:121308. [PMID: 26456687 DOI: 10.1117/1.jbo.20.12.121308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 08/31/2015] [Indexed: 06/05/2023]
Abstract
We introduce a microfluidic approach to simulate tumor hypoxia and vascular anomaly. Polydimethylsiloxane (PDMS) phantoms with embedded microchannel networks were fabricated by a soft lithography process. A dialysis membrane was sandwiched between two PDMS slabs to simulate the controlled mass transport and oxygen metabolism. A tortuous microchannel network was fabricated to simulate tumor microvasculature. A dual-modal multispectral and laser speckle imaging system was used for oxygen and blood flow imaging in the tumor-simulating phantom. The imaging results were compared with those of the normal vasculature. Our experiments demonstrated the technical feasibility of simulating tumor hypoxia and vascular anomalies using the proposed PDMS phantom. Such a phantom fabrication technique may be potentially used to calibrate optical imaging devices, to study the mechanisms for tumor hypoxia and angiogenesis, and to optimize the drug delivery strategies.
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Affiliation(s)
- Qiang Wu
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, China
| | - Wenqi Ren
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, ChinabThe Ohio State University, Department of Biomedical Engineering, 1080 Carmack Road, Columbus, Ohio
| | - Zelin Yu
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, China
| | - Erbao Dong
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, China
| | - Shiwu Zhang
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, China
| | - Ronald X Xu
- University of Science and Technology of China, Department of Precision Machinery and Precision Instrumentation, 96 Jinzhai Road, Hefei, Anhui 230027, ChinabThe Ohio State University, Department of Biomedical Engineering, 1080 Carmack Road, Columbus, Ohio
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66
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Sieno LD, Mora AD, Boso G, Tosi A, Pifferi A, Cubeddu R, Contini D. Diffuse optics using a dual window fast-gated counter. APPLIED OPTICS 2014; 53:7394-401. [PMID: 25402904 DOI: 10.1364/ao.53.007394] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In this paper we demonstrate the advantages of a fast-gated counter in achieving high count-rate and reducing costs of timing equipment in a time-resolved diffuse optical spectroscopy setup. We experimentally prove the equivalence between the fast-gated counter we developed and a traditional time-correlated single-photon counting setup in terms of depth sensitivity and signal-to-noise ratio. Additionally, we show the suitability of this device for bilayer analysis and to estimate the absorption coefficient of homogeneous diffusing media. Finally, we present a proof-of-principle arterial occlusion measurement on a healthy volunteer to validate the proposed approach in a real application. Fast-gated counters can dramatically reduce both costs and complexity in time-resolved multichannel systems, while achieving high count-rate, thus offering a great advantage in applications like brain and muscle functional imaging.
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67
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Wabnitz H, Jelzow A, Mazurenka M, Steinkellner O, Macdonald R, Milej D, Żołek N, Kacprzak M, Sawosz P, Maniewski R, Liebert A, Magazov S, Hebden J, Martelli F, Di Ninni P, Zaccanti G, Torricelli A, Contini D, Re R, Zucchelli L, Spinelli L, Cubeddu R, Pifferi A. Performance assessment of time-domain optical brain imagers, part 2: nEUROPt protocol. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086012. [PMID: 25121480 DOI: 10.1117/1.jbo.19.8.086012] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/21/2014] [Indexed: 05/18/2023]
Abstract
The nEUROPt protocol is one of two new protocols developed within the European project nEUROPt to characterize the performances of time-domain systems for optical imaging of the brain. It was applied in joint measurement campaigns to compare the various instruments and to assess the impact of technical improvements. This protocol addresses the characteristic of optical brain imaging to detect, localize, and quantify absorption changes in the brain. It was implemented with two types of inhomogeneous liquid phantoms based on Intralipid and India ink with well-defined optical properties. First, small black inclusions were used to mimic localized changes of the absorption coefficient. The position of the inclusions was varied in depth and lateral direction to investigate contrast and spatial resolution. Second, two-layered liquid phantoms with variable absorption coefficients were employed to study the quantification of layer-wide changes and, in particular, to determine depth selectivity, i.e., the ratio of sensitivities for deep and superficial absorption changes. We introduce the tests of the nEUROPt protocol and present examples of results obtained with different instruments and methods of data analysis. This protocol could be a useful step toward performance tests for future standards in diffuse optical imaging.
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Affiliation(s)
- Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Alexander Jelzow
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Mikhail Mazurenka
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Oliver Steinkellner
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Rainer Macdonald
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Daniel Milej
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Norbert Żołek
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Michal Kacprzak
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Piotr Sawosz
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Roman Maniewski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Adam Liebert
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Salavat Magazov
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London WC1E 6BT, United Kingdom
| | - Jeremy Hebden
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London WC1E 6BT, United Kingdom
| | - Fabrizio Martelli
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Paola Di Ninni
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Giovanni Zaccanti
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Alessandro Torricelli
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Davide Contini
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Rebecca Re
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lucia Zucchelli
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Rinaldo Cubeddu
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, ItalyfIstituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Antonio Pifferi
- Politecnico di Milano-Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, ItalyfIstituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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68
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Wabnitz H, Taubert DR, Mazurenka M, Steinkellner O, Jelzow A, Macdonald R, Milej D, Sawosz P, Kacprzak M, Liebert A, Cooper R, Hebden J, Pifferi A, Farina A, Bargigia I, Contini D, Caffini M, Zucchelli L, Spinelli L, Cubeddu R, Torricelli A. Performance assessment of time-domain optical brain imagers, part 1: basic instrumental performance protocol. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086010. [PMID: 25121479 DOI: 10.1117/1.jbo.19.8.086010] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/21/2014] [Indexed: 05/20/2023]
Abstract
Performance assessment of instruments devised for clinical applications is of key importance for validation and quality assurance. Two new protocols were developed and applied to facilitate the design and optimization of instruments for time-domain optical brain imaging within the European project nEUROPt. Here, we present the "Basic Instrumental Performance" protocol for direct measurement of relevant characteristics. Two tests are discussed in detail. First, the responsivity of the detection system is a measure of the overall efficiency to detect light emerging from tissue. For the related test, dedicated solid slab phantoms were developed and quantitatively spectrally characterized to provide sources of known radiance with nearly Lambertian angular characteristics. The responsivity of four time-domain optical brain imagers was found to be of the order of 0.1 m² sr. The relevance of the responsivity measure is demonstrated by simulations of diffuse reflectance as a function of source-detector separation and optical properties. Second, the temporal instrument response function (IRF) is a critically important factor in determining the performance of time-domain systems. Measurements of the IRF for various instruments were combined with simulations to illustrate the impact of the width and shape of the IRF on contrast for a deep absorption change mimicking brain activation.
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Affiliation(s)
- Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | | | - Mikhail Mazurenka
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Oliver Steinkellner
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Alexander Jelzow
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Rainer Macdonald
- Physikalisch-Technische Bundesanstalt (PTB), Abbestraße 2-12, 10587 Berlin, Germany
| | - Daniel Milej
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Piotr Sawosz
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Michał Kacprzak
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Adam Liebert
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Robert Cooper
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London WC1E 6BT, United Kingdom
| | - Jeremy Hebden
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London WC1E 6BT, United Kingdom
| | - Antonio Pifferi
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, ItalyeIstituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Ilaria Bargigia
- Istituto Italiano di Tecnologia, Center for Nano Science and Technology @ PoliMi, via Pascoli 70/3, 20133 Milano, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Matteo Caffini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lucia Zucchelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Rinaldo Cubeddu
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, ItalyeIstituto di Fotonica e Nanotecnologie, CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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69
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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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70
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Martelli F, Di Ninni P, Zaccanti G, Contini D, Spinelli L, Torricelli A, Cubeddu R, Wabnitz H, Mazurenka M, Macdonald R, Sassaroli A, Pifferi A. Phantoms for diffuse optical imaging based on totally absorbing objects, part 2: experimental implementation. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:076011. [PMID: 25023415 DOI: 10.1117/1.jbo.19.7.076011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/05/2014] [Indexed: 05/19/2023]
Abstract
We present the experimental implementation and validation of a phantom for diffuse optical imaging based on totally absorbing objects for which, in the previous paper [J. Biomed. Opt.18(6), 066014, (2013)], we have provided the basic theory. Totally absorbing objects have been manufactured as black polyvinyl chloride (PVC) cylinders and the phantom is a water dilution of intralipid-20% as the diffusive medium and India ink as the absorber, filled into a black scattering cell made of PVC. By means of time-domain measurements and of Monte Carlo simulations, we have shown the reliability, the accuracy, and the robustness of such a phantom in mimicking typical absorbing perturbations of diffuse optical imaging. In particular, we show that such a phantom can be used to generate any absorption perturbation by changing the volume and position of the totally absorbing inclusion.
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Affiliation(s)
- Fabrizio Martelli
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Paola Di Ninni
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Giovanni Zaccanti
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
| | - Davide Contini
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Lorenzo Spinelli
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Alessandro Torricelli
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Rinaldo Cubeddu
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, ItalycIstituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin, Germany
| | - Mikhail Mazurenka
- Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin, Germany
| | - Rainer Macdonald
- Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin, Germany
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, Massachusetts 02155, United States
| | - Antonio Pifferi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, ItalycIstituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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71
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Torricelli A, Contini D, Pifferi A, Caffini M, Re R, Zucchelli L, Spinelli L. Time domain functional NIRS imaging for human brain mapping. Neuroimage 2014; 85 Pt 1:28-50. [DOI: 10.1016/j.neuroimage.2013.05.106] [Citation(s) in RCA: 294] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 04/25/2013] [Accepted: 05/21/2013] [Indexed: 02/02/2023] Open
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72
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Watté R, Do Trong NN, Aernouts B, Erkinbaev C, De Baerdemaeker J, Nicolaï B, Saeys W. Metamodeling approach for efficient estimation of optical properties of turbid media from spatially resolved diffuse reflectance measurements. OPTICS EXPRESS 2013; 21:32630-42. [PMID: 24514857 DOI: 10.1364/oe.21.032630] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A metamodeling approach is introduced and applied to efficiently estimate the bulk optical properties of turbid media from spatially resolved spectroscopy (SRS) measurements. The model has been trained on a set of liquid phantoms covering a wide range of optical properties representative for food and agricultural products and was successfully validated in forward and inverse mode on phantoms not used for training the model. With relative prediction errors of 10% for the estimated bulk optical properties the potential of this metamodeling approach for the estimation of the optical properties of turbid media from spatially resolved spectroscopy measurements has been demonstrated.
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73
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Re R, Contini D, Turola M, Spinelli L, Zucchelli L, Caffini M, Cubeddu R, Torricelli A. Multi-channel medical device for time domain functional near infrared spectroscopy based on wavelength space multiplexing. BIOMEDICAL OPTICS EXPRESS 2013; 4:2231-46. [PMID: 24156079 PMCID: PMC3799681 DOI: 10.1364/boe.4.002231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/12/2013] [Accepted: 09/17/2013] [Indexed: 05/03/2023]
Abstract
We have designed a compact dual wavelength (687 nm, 826 nm) multi-channel (16 sources, 8 detectors) medical device for muscle and brain imaging based on time domain functional near infrared spectroscopy. The system employs the wavelength space multiplexing approach to reduce wavelength cross-talk and increase signal-to-noise ratio. System performances have been tested on homogeneous and heterogeneous tissue phantoms following specifically designed protocols for photon migration instruments. Preliminary in vivo measurements have been performed to validate the instrument capability to monitor hemodynamic parameters changes in the arm muscle during arterial occlusion and in the adult head during a motor task experiment.
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Affiliation(s)
- Rebecca Re
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Davide Contini
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Massimo Turola
- Division of Optometry and Visual Sciences, City University London, Northampton Square, EC1V 0HB London, UK
| | | | - Lucia Zucchelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Matteo Caffini
- Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Via Golgi 39, 20133 Milan, Italy
| | - Rinaldo Cubeddu
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
| | - Alessandro Torricelli
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan, Italy
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74
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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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75
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Martelli F, Pifferi A, Contini D, Spinelli L, Torricelli A, Wabnitz H, Macdonald R, Sassaroli A, Zaccanti G. Phantoms for diffuse optical imaging based on totally absorbing objects, part 1: Basic concepts. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:066014. [PMID: 23778947 PMCID: PMC4023647 DOI: 10.1117/1.jbo.18.6.066014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/17/2013] [Accepted: 05/06/2013] [Indexed: 05/20/2023]
Abstract
The design of inhomogeneous phantoms for diffuse optical imaging purposes using totally absorbing objects embedded in a diffusive medium is proposed and validated. From time-resolved and continuous-wave Monte Carlo simulations, it is shown that a given or desired perturbation strength caused by a realistic absorbing inhomogeneity of a certain absorption and volume can be approximately mimicked by a small totally absorbing object of a so-called equivalent black volume (equivalence relation). This concept can be useful in two ways. First, it can be exploited to design realistic inhomogeneous phantoms with different perturbation strengths simply using a set of black objects with different volumes. Further, it permits one to grade physiological or pathological changes on a reproducible scale of perturbation strengths given as equivalent black volumes, thus facilitating the performance assessment of clinical instruments. A set of plots and interpolating functions to derive the equivalent black volume corresponding to a given absorption change is provided. The application of the equivalent black volume concept for grading different optical perturbations is demonstrated for some examples.
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Affiliation(s)
- Fabrizio Martelli
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy.
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76
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Herremans E, Bongaers E, Estrade P, Gondek E, Hertog M, Jakubczyk E, Nguyen Do Trong N, Rizzolo A, Saeys W, Spinelli L, Torricelli A, Vanoli M, Verboven P, Nicolaï B. Microstructure–texture relationships of aerated sugar gels: Novel measurement techniques for analysis and control. INNOV FOOD SCI EMERG 2013. [DOI: 10.1016/j.ifset.2013.02.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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77
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Cerussi AE, Warren R, Hill B, Roblyer D, Leproux A, Durkin AF, O’Sullivan TD, Keene S, Haghany H, Quang T, Mantulin WM, Tromberg BJ. Tissue phantoms in multicenter clinical trials for diffuse optical technologies. BIOMEDICAL OPTICS EXPRESS 2012; 3:966-71. [PMID: 22567589 PMCID: PMC3342201 DOI: 10.1364/boe.3.000966] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 03/27/2012] [Indexed: 05/03/2023]
Abstract
Tissue simulating phantoms are an important part of instrumentation validation, standardization/training and clinical translation. Properly used, phantoms form the backbone of sound quality control procedures. We describe the development and testing of a series of optically turbid phantoms used in a multi-center American College of Radiology Imaging Network (ACRIN) clinical trial of Diffuse Optical Spectroscopic Imaging (DOSI). The ACRIN trial is designed to measure the response of breast tumors to neoadjuvant chemotherapy. Phantom measurements are used to determine absolute instrument response functions during each measurement session and assess both long and short-term operator and instrument reliability.
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Affiliation(s)
- Albert E. Cerussi
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Robert Warren
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Brian Hill
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Darren Roblyer
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Anaїs Leproux
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Amanda F. Durkin
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Thomas D. O’Sullivan
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Sam Keene
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Hosain Haghany
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Timothy Quang
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - William M. Mantulin
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
| | - Bruce J. Tromberg
- Beckman Laser Institute, University of California Irvine, Irvine, California 92617, USA
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78
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Martelli F, Bianco SD, Zaccanti G. Retrieval procedure for time-resolved near-infrared tissue spectroscopy based on the optimal estimation method. Phys Med Biol 2012; 57:2915-29. [DOI: 10.1088/0031-9155/57/10/2915] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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79
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Di Ninni P, Martelli F, Zaccanti G. Effect of dependent scattering on the optical properties of Intralipid tissue phantoms. BIOMEDICAL OPTICS EXPRESS 2011; 2:2265-78. [PMID: 21833363 PMCID: PMC3149524 DOI: 10.1364/boe.2.002265] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 06/29/2011] [Accepted: 07/06/2011] [Indexed: 05/21/2023]
Abstract
The calibration of optical tissue-simulating phantoms remains an open question in spite of the many techniques proposed for accurate measurements of optical properties. As a consequence, a reference phantom with well known optical properties is still missing. As a first step towards a reference phantom we have recently proposed to use dilutions of Intralipid 20%. In this paper we discuss a matter that is commonly ignored when dilutions are prepared, i.e., the possibility of deviations from the simple linear relationships between the optical properties of the dilution and the Intralipid concentration due to the effects of dependent scattering. The results of an experimental investigation showed that dependent scattering does not affect absorption. As for the reduced scattering coefficient the effect can be described adding a term proportional to the square of the concentration. However, for concentrations of interest for tissue optics deviations from linearity remain within about 2%. The experimental investigation also showed that the microphysical properties of Intralipid are not affected by dilution. These results show the possibility to easily obtain a liquid diffusive phantom whose optical properties are known with error smaller than about 1%. Due to the intrinsic limitations of the different techniques proposed for measuring the optical properties it seems difficult to obtain a similar accuracy for solid phantoms.
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80
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Dehaes M, Grant PE, Sliva DD, Roche-Labarbe N, Pienaar R, Boas DA, Franceschini MA, Selb J. Assessment of the frequency-domain multi-distance method to evaluate the brain optical properties: Monte Carlo simulations from neonate to adult. BIOMEDICAL OPTICS EXPRESS 2011; 2:552-67. [PMID: 21412461 PMCID: PMC3047361 DOI: 10.1364/boe.2.000552] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/03/2011] [Accepted: 02/04/2011] [Indexed: 05/18/2023]
Abstract
The near infrared spectroscopy (NIRS) frequency-domain multi-distance (FD-MD) method allows for the estimation of optical properties in biological tissue using the phase and intensity of radiofrequency modulated light at different source-detector separations. In this study, we evaluated the accuracy of this method to retrieve the absorption coefficient of the brain at different ages. Synthetic measurements were generated with Monte Carlo simulations in magnetic resonance imaging (MRI)-based heterogeneous head models for four ages: newborn, 6 and 12 month old infants, and adult. For each age, we determined the optimal set of source-detector separations and estimated the corresponding errors. Errors arise from different origins: methodological (FD-MD) and anatomical (curvature, head size and contamination by extra-cerebral tissues). We found that the brain optical absorption could be retrieved with an error between 8-24% in neonates and infants, while the error increased to 19-44% in adults over all source-detector distances. The dominant contribution to the error was found to be the head curvature in neonates and infants, and the extra-cerebral tissues in adults.
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Affiliation(s)
- Mathieu Dehaes
- Fetal-Neonatal Neuroimaging & Development Science Center, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - P. Ellen Grant
- Fetal-Neonatal Neuroimaging & Development Science Center, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Danielle D. Sliva
- Fetal-Neonatal Neuroimaging & Development Science Center, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Nadège Roche-Labarbe
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Rudolph Pienaar
- Fetal-Neonatal Neuroimaging & Development Science Center, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Maria Angela Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Juliette Selb
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA
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81
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Ninni PD, Martelli F, Zaccanti G. Intralipid: towards a diffusive reference standard for optical tissue phantoms. Phys Med Biol 2010; 56:N21-8. [PMID: 21160111 DOI: 10.1088/0031-9155/56/2/n01] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Measurements of optical properties carried out at visible and NIR wavelengths on many samples of Intralipid 20% showed a high stability and surprisingly small batch-to-batch variations. Measurements have been carried out in a short time interval using samples from nine different batches with expiry dates spreading over ten years. For the specific reduced scattering coefficient, the values we have obtained, averaged over the nine batches, are 25.9, 21.2, and 18.4 mm(-1) at λ = 632.8, 751, and 833 nm, respectively, and the corresponding maximum deviations from the average were 2.2%, 1.1%, and 1.4%. For the absorption coefficient, we obtained values slightly smaller with respect to the absorption coefficient of pure water at 751 and 833 nm, and slightly larger at 632.8 nm. These results suggest that Intralipid 20% can be the first step towards a diffusive reference standard for tissue-simulating phantoms.
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Affiliation(s)
- Paola Di Ninni
- Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy
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82
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Re R, Contini D, Caffini M, Cubeddu R, Spinelli L, Torricelli A. A compact time-resolved system for near infrared spectroscopy based on wavelength space multiplexing. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:113101. [PMID: 21133455 DOI: 10.1063/1.3495957] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We designed and developed a compact dual-wavelength and dual-channel time-resolved system for near-infrared spectroscopy studies of muscle and brain. The system employs pulsed diode lasers as sources, compact photomultipliers, and time-correlated single photon counting boards for detection. To exploit the full temporal and dynamic range of the acquisition technique, we implemented an approach based on wavelength space multiplexing: laser pulses at the two wavelengths are alternatively injected into the two channels by means of an optical 2×2 switch. In each detection line (i.e., in each temporal window), the distribution of photon time-of-flights at one wavelength is acquired. The proposed approach increases the signal-to-noise ratio and avoids wavelength cross-talk with respect to the typical approach based on time multiplexing. The instrument was characterized on tissue phantoms to assess its properties in terms of linearity, stability, noise, and reproducibility. Finally, it was successfully tested in preliminary in vivo measurements on muscle during standard cuff occlusion and on the brain during a motor cortex response due to hand movements.
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Affiliation(s)
- Rebecca Re
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
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83
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Soloviev VY, D'Andrea C, Mohan PS, Valentini G, Cubeddu R, Arridge SR. Fluorescence lifetime optical tomography with Discontinuous Galerkin discretisation scheme. BIOMEDICAL OPTICS EXPRESS 2010; 1:998-1013. [PMID: 21258525 PMCID: PMC3018046 DOI: 10.1364/boe.1.000998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/07/2010] [Accepted: 09/12/2010] [Indexed: 05/23/2023]
Abstract
We develop discontinuous Galerkin framework for solving direct and inverse problems in fluorescence diffusion optical tomography in turbid media. We show the advantages and the disadvantages of this method by comparing it with previously developed framework based on the finite volume discretization. The reconstruction algorithm was used with time-gated experimental dataset acquired by imaging a highly scattering cylindrical phantom concealing small fluorescent tubes. Optical parameters, quantum yield and lifetime were simultaneously reconstructed. Reconstruction results are presented and discussed.
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Affiliation(s)
- Vadim Y. Soloviev
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Cosimo D'Andrea
- Centre for Nano Science and Technology of Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - P. Surya Mohan
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Gianluca Valentini
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Rinaldo Cubeddu
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Simon R. Arridge
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
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84
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Zarychta K, Tinet E, Azizi L, Avrillier S, Ettori D, Tualle JM. Time-resolved diffusing wave spectroscopy with a CCD camera. OPTICS EXPRESS 2010; 18:16289-301. [PMID: 20721015 DOI: 10.1364/oe.18.016289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We show how time-resolved measurements of the diffuse light transmitted through a thick scattering slab can be performed with a standard CCD camera, thanks to an interferometric protocol. Time-resolved correlations measured at a fixed photon transit time are also presented. The high number of pixels of the camera allows us to attain a quite good sensitivity for a reasonably low acquisition time.
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Affiliation(s)
- Katarzyna Zarychta
- Laboratoire de Physique des Lasers, Institut Galilée, Université Paris 13, 99 Ave JB Clément, F-93430 Villetaneuse, France
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85
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Cen H, Lu R. Optimization of the hyperspectral imaging-based spatially-resolved system for measuring the optical properties of biological materials. OPTICS EXPRESS 2010; 18:17412-32. [PMID: 20721128 DOI: 10.1364/oe.18.017412] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This paper reports on the optimization and assessment of a hyperspectral imaging-based spatially-resolved system for determination of the optical properties of biological materials over the wavelengths of 500-1,000 nm. Twelve model samples covering a wide range of absorption and reduced scattering coefficients were created to validate the hyperspectral imaging system, and their true values of absorption and reduced scattering coefficients were determined and then cross-validated using three commonly used methods (i.e., transmittance, integrating sphere, and empirical equation). Light beam and source-detector distance were optimized through Monte Carlo simulations and experiments for the model samples. The optimal light beam should be of Gaussian type with the diameter of less than 1 mm, and the optimal minimum and maximum source-detector distance should be 1.5 mm and 10-20 mean free paths, respectively. The optimized hyperspectral imaging-based spatially-resolved system achieved good estimation of the optical parameters.
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Affiliation(s)
- Haiyan Cen
- Department of Biosystems and Agricultural Engineering, 105A Farrall Hall, Michigan State University, East Lansing, Michigan 48824, USA
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86
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Bouchard JP, Veilleux I, Jedidi R, Noiseux I, Fortin M, Mermut O. Reference optical phantoms for diffuse optical spectroscopy. Part 1--Error analysis of a time resolved transmittance characterization method. OPTICS EXPRESS 2010; 18:11495-507. [PMID: 20589010 DOI: 10.1364/oe.18.011495] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Development, production quality control and calibration of optical tissue-mimicking phantoms require a convenient and robust characterization method with known absolute accuracy. We present a solid phantom characterization technique based on time resolved transmittance measurement of light through a relatively small phantom sample. The small size of the sample enables characterization of every material batch produced in a routine phantoms production. Time resolved transmittance data are pre-processed to correct for dark noise, sample thickness and instrument response function. Pre-processed data are then compared to a forward model based on the radiative transfer equation solved through Monte Carlo simulations accurately taking into account the finite geometry of the sample. The computational burden of the Monte-Carlo technique was alleviated by building a lookup table of pre-computed results and using interpolation to obtain modeled transmittance traces at intermediate values of the optical properties. Near perfect fit residuals are obtained with a fit window using all data above 1% of the maximum value of the time resolved transmittance trace. Absolute accuracy of the method is estimated through a thorough error analysis which takes into account the following contributions: measurement noise, system repeatability, instrument response function stability, sample thickness variation refractive index inaccuracy, time correlated single photon counting system time based inaccuracy and forward model inaccuracy. Two sigma absolute error estimates of 0.01 cm(-1) (11.3%) and 0.67 cm(-1) (6.8%) are obtained for the absorption coefficient and reduced scattering coefficient respectively.
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87
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Guyon L, da Silva A, Planat-Chrétien A, Rizo P, Dinten JM. Chi2 analysis for estimating the accuracy of optical properties derived from time resolved diffuse-reflectance. OPTICS EXPRESS 2009; 17:20521-20537. [PMID: 19997281 DOI: 10.1364/oe.17.020521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Weighted residuals and the reduced chi(2) (chi(R) (2)) value are investigated with regard to their relevance for assessing optical property estimates using the diffusion equation for time-resolved measurements in turbid media. It is shown and explained, for all photon counting experiments including lifetime estimation, why chi(R) (2) increases linearly with the number of photons when there is a model bias. Only when a sufficient number of photons has been acquired, chi(R) (2) is a pertinent value for assessing the accuracy of mu(a) and mu(s)' estimates. It was concluded that chi(R) (2) is of particular interest for cases of small interfiber separation, low-level scattering, strong absorption and incorrect measurement of instrument response function. It was also found that chi(R) (2) is less pertinent for judging mu(a) in case of air boundary effects.
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Affiliation(s)
- Laurent Guyon
- CEA, LETI, Département Technologies pour la Biologie et la Santé, F-38054 Grenoble, France.
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88
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Svensson T, Alerstam E, Khoptyar D, Johansson J, Folestad S, Andersson-Engels S. Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2009; 80:063105. [PMID: 19566194 DOI: 10.1063/1.3156047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Photon time-of-flight spectroscopy (PTOFS) is a powerful tool for analysis of turbid materials. We have constructed a time-of-flight spectrometer based on a supercontinuum fiber laser, acousto-optical tunable filtering, and an InP/InGaAsP microchannel plate photomultiplier tube. The system is capable of performing PTOFS up to 1400 nm, and thus covers an important region for vibrational spectroscopy of solid samples. The development significantly increases the applicability of PTOFS for analysis of chemical content and physical properties of turbid media. The great value of the proposed approach is illustrated by revealing the distinct absorption features of turbid epoxy resin. Promising future applications of the approach are discussed, including quantitative assessment of pharmaceuticals, powder analysis, and calibration-free near-infrared spectroscopy.
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Affiliation(s)
- Tomas Svensson
- Department of Physics, Lund University, P.O. Box 118, S-221 00 Lund, Sweden
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89
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Cletus B, Künnemeyer R, Martinsen P, McGlone A, Jordan R. Characterizing liquid turbid media by frequency-domain photon-migration spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:024041. [PMID: 19405769 DOI: 10.1117/1.3119282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a wavelength-tunable frequency-domain instrument for the characterization of liquid turbid media. The instrument employs a tunable titanium-sapphire laser modulated by an acousto-optic modulator. The absorption and reduced scattering coefficient of Intralipid(R) 20%, diluted to concentrations of 0.94 to 4.00%, are measured over the wavelength range 710 to 850 nm at 10-nm intervals. The standard measurement errors for the absorption and reduced scattering coefficients are 1 and 2.5%, respectively. Extrapolation to 0% Intralipid(R) concentration gives an absorption coefficient that closely follows that of water, overestimating the absorption of pure water by less than 10%. The reduced scattering coefficient is compared at 750 nm with published results and is found consistent within the experimental error. We compare the reduced scattering coefficient to an estimate based on Mie theory and find the reduced scattering coefficient underestimated the Mie theory result by about 9%.
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Affiliation(s)
- Biju Cletus
- The University of Waikato, Hillcrest Road, Hamilton, Waikato 3210, New Zealand.
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90
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Fang Q, Carp SA, Selb J, Boverman G, Zhang Q, Kopans DB, Moore RH, Miller EL, Brooks DH, Boas DA. Combined optical imaging and mammography of the healthy breast: optical contrast derived from breast structure and compression. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:30-42. [PMID: 19116186 PMCID: PMC2642986 DOI: 10.1109/tmi.2008.925082] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In this paper, we report new progress in developing the instrument and software platform of a combined X-ray mammography/diffuse optical breast imaging system. Particularly, we focus on system validation using a series of balloon phantom experiments and the optical image analysis of 49 healthy patients. Using the finite-element method for forward modeling and a regularized Gauss-Newton method for parameter reconstruction, we recovered the inclusions inside the phantom and the hemoglobin images of the human breasts. An enhanced coupling coefficient estimation scheme was also incorporated to improve the accuracy and robustness of the reconstructions. The recovered average total hemoglobin concentration (HbT) and oxygen saturation (SO2) from 68 breast measurements are 16.2 microm and 71%, respectively, where the HbT presents a linear trend with breast density. The low HbT value compared to literature is likely due to the associated mammographic compression. From the spatially co-registered optical/X-ray images, we can identify the chest-wall muscle, fatty tissue, and fibroglandular regions with an average HbT of 20.1+/-6.1 microm for fibroglandular tissue, 15.4+/-5.0 microm for adipose, and 22.2+/-7.3 microm for muscle tissue. The differences between fibroglandular tissue and the corresponding adipose tissue are significant (p < 0.0001). At the same time, we recognize that the optical images are influenced, to a certain extent, by mammographical compression. The optical images from a subset of patients show composite features from both tissue structure and pressure distribution. We present mechanical simulations which further confirm this hypothesis.
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Affiliation(s)
- Qianqian Fang
- Massachusetts General Hospital, Charlestown, MA 02148 USA.
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91
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Soloviev VY, D'Andrea C, Valentini G, Cubeddu R, Arridge SR. Combined reconstruction of fluorescent and optical parameters using time-resolved data. APPLIED OPTICS 2009; 48:28-36. [PMID: 19107168 DOI: 10.1364/ao.48.000028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We present an algorithm for simultaneous reconstruction of optical parameters, quantum yield, and lifetime in turbid media with embedded fluorescent inclusions. This algorithm is designed in the Fourier domain as an iterative solution of a system of differential equations of the Helmholtz type and does not involve full ill-conditioned matrix computations. The approach is based on allowing the unknown optical parameters, quantum yield, and lifetime to depend on the Fourier spectral parameter. The algorithm was applied to a time-gated experimental data set acquired by imaging a highly scattering cylindrical phantom concealing small fluorescent tubes. Relatively accurate reconstruction demonstrates the potential of the method.
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Affiliation(s)
- Vadim Y Soloviev
- Department of Computer Science, University College London, Gower Street, London WC1E 6BT, UK.
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92
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Alerstam E, Andersson-Engels S, Svensson T. White Monte Carlo for time-resolved photon migration. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:041304. [PMID: 19021312 DOI: 10.1117/1.2950319] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A novel scheme for fully scalable White Monte Carlo (WMC) has been developed and is used as a forward solver in the evaluation of experimental time-resolved spectroscopy. Previously reported scaling problems are avoided by storing detection events individually, turning spatial and temporal binning into post-simulation activities. The approach is suitable for modeling of both interstitial and noninvasive settings (i.e., infinite and semi-infinite geometries). Motivated by an interest in in vivo optical properties of human prostate tissue, we utilize WMC to explore the low albedo regime of time-domain photon migration--a regime where the diffusion approximation of radiative transport theory breaks down, leading to the risk of overestimating both reduced scattering (mu(s)') and absorption (mu(a)). Experimental work supports our findings and establishes the advantages of Monte Carlo-based evaluation.
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93
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D'Andrea C, Farina A, Comelli D, Pifferi A, Taroni P, Valentini G, Cubeddu R, Zoia L, Orlandi M, Kienle A. Time-resolved optical spectroscopy of wood. APPLIED SPECTROSCOPY 2008; 62:569-574. [PMID: 18498699 DOI: 10.1366/000370208784344424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We have proposed and experimentally demonstrated that picosecond time-resolved optical spectroscopy in the visible/near-infrared (NIR) region (700-1040 nm) is a useful technique for noninvasive characterization of wood. This technique has been demonstrated on both softwood and hardwood samples treated in different ways simulating the aging process suffered by waterlogged woods. In all the cases, alterations of absorption and scattering spectra were observed, revealing changes of chemical and structural composition.
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Affiliation(s)
- C D'Andrea
- CNR-INFM and CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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94
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Pifferi A, Torricelli A, Taroni P, Comelli D, Bassi A, Cubeddu R. Fully automated time domain spectrometer for the absorption and scattering characterization of diffusive media. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:053103. [PMID: 17552808 DOI: 10.1063/1.2735567] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We describe a system for absorption and scattering spectroscopy of diffusive media based on time-resolved reflectance and transmittance measurements. The system is operated with mode-locked lasers tunable in the 550-1050 nm spectral range and on a detection chain based on time-correlated single-photon counting. All measurement procedures such as laser tuning and optimization, signal conditioning, data acquisition, and analysis are completely automated, permitting spectral measurements over the whole range in a few minutes. The criticalities of the system are discussed together with the strategies to compensate them. The Medphot protocol devised for the characterization of photon migration instruments was applied to assess the system performances in terms of accuracy, linearity, noise, stability, and reproducibility. Finally, an example of application of the instrument to the spectroscopy of powders is presented.
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Affiliation(s)
- Antonio Pifferi
- ULTRAS-CNR-INFM and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan, Italy.
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95
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Kacprzak M, Liebert A, Sawosz P, Zolek N, Maniewski R. Time-resolved optical imager for assessment of cerebral oxygenation. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:034019. [PMID: 17614727 DOI: 10.1117/1.2743964] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A time-resolved optical instrument allowing for noninvasive assessment of cerebral oxygenation is presented. The instrument is equipped with picosecond diode lasers, fast photodetectors, and time-correlated single photon counting electronics. This technology enables depth-resolved estimation of changes in absorption and, in consequence, assessment of changes in hemoglobin concentrations in the brain cortex. Changes in oxyhemoglobin (HbO(2)) and deoxyhemoglobin (Hb) can be evaluated selectively in extra- and intracerebral tissue compartments using the moments of distributions of times of flight of photons measured at two wavelengths in the near-infrared region. The combination of the data acquired from multiple sources and detectors located on the surface of the head with the depth-resolved analysis, based on the moments, enables imaging of cortex oxygenation. Results of the tests on physical phantoms as well as in vivo validation of the instrument during the motor stimulation experiment are presented.
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Affiliation(s)
- Michal Kacprzak
- Institute of Biocybernetics and Biomedical Engineering, Trojdena 4, 02-109 Warsaw, Poland.
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96
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Comelli D, Bassi A, Pifferi A, Taroni P, Torricelli A, Cubeddu R, Martelli F, Zaccanti G. In vivo time-resolved reflectance spectroscopy of the human forehead. APPLIED OPTICS 2007; 46:1717-25. [PMID: 17356614 DOI: 10.1364/ao.46.001717] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We present an in vivo broadband spectroscopic characterization of the human forehead. Absorption and scattering properties are measured on five healthy volunteers at five different interfiber distances, using time-resolved diffuse spectroscopy and interpreting data with a model of the diffusion equation for a homogeneous semi-infinite medium. A wavelength-tunable mode-locked laser and time-correlated single-photon counting detection are employed, enabling fully spectroscopic measurements in the range of 700-1000 nm. The results show a large variation in the absorption and scattering properties of the head depending on the subject, whereas intrasubject variations, assessed at different interfiber distances, appear less relevant, particularly for what concerns the absorption coefficient. The high intersubject variability observed indicates that a unique set of optical properties for modeling the human head cannot be used correctly. To better interpret the results of the analysis of in vivo measurements, we performed a set of four-layer model Monte Carlo simulations based on different data sets for the optical properties of the human head, partially derived from the literature. The analysis indicated that, when simulated time-resolved curves are fitted with a homogeneous model for the photon migration, the retrieved absorption and reduced scattering coefficients are much closer to superficial layer values (i.e., scalp and skull) than to deeper layer ones (white and gray matter). In particular, for the shorter interfiber distances, the recovered values can be assumed as a good estimate of the optical properties of the first layer.
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Affiliation(s)
- Daniela Comelli
- Centre of Ultrafast and Ultraintense Optical Science, Consiglio Nazionale delle Ricerche, Istituto Nazionale de Fisica della Materia, Politecnico di Milano, Milano, Italy.
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97
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Martelli F, Zaccanti G. Calibration of scattering and absorption properties of a liquid diffusive medium at NIR wavelengths. CW method. OPTICS EXPRESS 2007; 15:486-500. [PMID: 19532267 DOI: 10.1364/oe.15.000486] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In spite of many progresses achieved both with theories and with experiments in studying light propagation through diffusive media, a reliable method for accurate measurements of the optical properties of diffusive media at NIR wavelengths is, in our opinion, still missing. It is therefore difficult to create a diffusive medium with well known optical properties to be used as a reference. In this paper we describe a method to calibrate the reduced scattering coefficient, mu'(s) , of a liquid diffusive medium and the absorption coefficient, mu(a), of an absorbing medium with a standard error smaller than 2% both on mu'(s) and on mu(a). The method is based on multidistance measurements of fluence into an infinite medium illuminated by a CW source. The optical properties are retrieved with simple inversion procedures (linear fits) exploiting the knowledge of the absorption coefficient of the liquid into which the diffuser and the absorber are dispersed. In this study Intralipid diluted in water has been used as diffusive medium and Indian ink as absorber. For a full characterization of these media measurements of collimated transmittance have also been carried out, from which the asymmetry factor of the scattering function of Intralipid and the single scattering albedo of Indian ink have been determined.
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98
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Svensson T, Andersson-Engels S, Einarsdóttír M, Svanberg K. In vivo optical characterization of human prostate tissue using near-infrared time-resolved spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:014022. [PMID: 17343497 DOI: 10.1117/1.2435175] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The development of photodynamic therapy into a modality for treatment of prostate cancer calls for reliable optical dosimetry. We employ, for the first time, interstitial time-resolved spectroscopy to determine in vivo optical properties of human prostate tissue. Nine patients are included in the study, and measurements are conducted prior to primary brachytherapy treatment of prostate cancer. Intrasubject variability is examined by measuring across three tissue volumes within each prostate. The time-resolved instrumentation proves its usefulness by producing good signal levels in all measurements. We are able to present consistent values on reduced scattering coefficients (mu(s)'), absorption coefficients (mu(a)), and effective attenuation (mu(eff)) at the wavelengths 660, 786, and 916 nm. At 660 nm, mu(s)' is found to be 9+/-2 cm(-1), and mu(a) is 0.5+/-0.1 cm(-1). Derived values of mu(eff) are in the range of 3 to 4 cm(-1) at 660 nm, a result in good agreement with previously published steady state data. Total hemoglobin concentration (THC) and oxygen saturation are spectroscopically determined using derived absorption coefficients. Derived THC values are fairly variable (215+/-65 microM), while derived values of oxygen saturation are gathered around 75% (76+/-4%). Intrasubject variations in derived parameters correlate (qualitatively) with the heterogeneity exhibited in acquired ultrasound images.
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Affiliation(s)
- Tomas Svensson
- Lund University, Department of Physics, SE-221 00 Lund, Sweden.
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99
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Pogue BW, Patterson MS. Review of tissue simulating phantoms for optical spectroscopy, imaging and dosimetry. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:041102. [PMID: 16965130 DOI: 10.1117/1.2335429] [Citation(s) in RCA: 370] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Optical spectroscopy, imaging, and therapy tissue phantoms must have the scattering and absorption properties that are characteristic of human tissues, and over the past few decades, many useful models have been created. In this work, an overview of their composition and properties is outlined, by separating matrix, scattering, and absorbing materials, and discussing the benefits and weaknesses in each category. Matrix materials typically are water, gelatin, agar, polyester or epoxy and polyurethane resin, room-temperature vulcanizing (RTV) silicone, or polyvinyl alcohol gels. The water and hydrogel materials provide a soft medium that is biologically and biochemically compatible with addition of organic molecules, and are optimal for scientific laboratory studies. Polyester, polyurethane, and silicone phantoms are essentially permanent matrix compositions that are suitable for routine calibration and testing of established systems. The most common three choices for scatters have been: (1.) lipid based emulsions, (2.) titanium or aluminum oxide powders, and (3.) polymer microspheres. The choice of absorbers varies widely from hemoglobin and cells for biological simulation, to molecular dyes and ink as less biological but more stable absorbers. This review is an attempt to indicate which sets of phantoms are optimal for specific applications, and provide links to studies that characterize main phantom material properties and recipes.
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Affiliation(s)
- Brian W Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, USA.
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100
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Abrahamsson C, Löwgren A, Strömdahl B, Svensson T, Andersson-Engels S, Johansson J, Folestad S. Scatter correction of transmission near-infrared spectra by photon migration data: quantitative analysis of solids. APPLIED SPECTROSCOPY 2005; 59:1381-7. [PMID: 16316516 DOI: 10.1366/000370205774783269] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The scope of this work is a new methodology to correct conventional near-infrared (NIR) data for scattering effects. The technique aims at measuring the absorption coefficient of the samples rather than the total attenuation measured in conventional NIR spectroscopy. The main advantage of this is that the absorption coefficient is independent of the path length of the light inside the sample and therefore independent of the scattering effects. The method is based on time-resolved spectroscopy and modeling of light transport by diffusion theory. This provides an independent measure of the scattering properties of the samples and therefore of the path length of light. This yields a clear advantage over other preprocessing techniques, where scattering effects are estimated and corrected for by using the shape of the measured spectrum only. Partial least squares (PLS) calibration models show that, by using the proposed evaluation scheme, the predictive ability is improved by 50% as compared to a model based on conventional NIR data alone. The method also makes it possible to predict the concentration of active substance in samples with other physical properties than the samples included in the calibration model.
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