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The Use of Supercontinuum Laser Sources in Biomedical Diffuse Optics: Unlocking the Power of Multispectral Imaging. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Optical techniques based on diffuse optics have been around for decades now and are making their way into the day-to-day medical applications. Even though the physics foundations of these techniques have been known for many years, practical implementation of these technique were hindered by technological limitations, mainly from the light sources and/or detection electronics. In the past 20 years, the developments of supercontinuum laser (SCL) enabled to unlock some of these limitations, enabling the development of system and methodologies relevant for medical use, notably in terms of spectral monitoring. In this review, we focus on the use of SCL in biomedical diffuse optics, from instrumentation and methods developments to their use for medical applications. A total of 95 publications were identified, from 1993 to 2021. We discuss the advantages of the SCL to cover a large spectral bandwidth with a high spectral power and fast switching against the disadvantages of cost, bulkiness, and long warm up times. Finally, we summarize the utility of using such light sources in the development and application of diffuse optics in biomedical sciences and clinical applications.
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2
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Broadband Time Domain Diffuse Optical Reflectance Spectroscopy: A Review of Systems, Methods, and Applications. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245465] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review presents recent developments and a wide overview of broadband time domain diffuse optical spectroscopy (TD-DOS). Various topics including physics of photon migration, advanced instrumentation, methods of analysis, applications covering multiple domains (tissue chromophore, in vivo studies, food, wood, pharmaceutical industry) are elaborated. The key role of standardization and recent studies in that direction are discussed. Towards the end, a brief outlook is presented on the current status and future trends in broadband TD-DOS.
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Baruch D, Abookasis D. Multimodal optical setup based on spectrometer and cameras combination for biological tissue characterization with spatially modulated illumination. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:46007. [PMID: 28425559 DOI: 10.1117/1.jbo.22.4.046007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
The application of optical techniques as tools for biomedical research has generated substantial interest for the ability of such methodologies to simultaneously measure biochemical and morphological parameters of tissue. Ongoing optimization of optical techniques may introduce such tools as alternative or complementary to conventional methodologies. The common approach shared by current optical techniques lies in the independent acquisition of tissue’s optical properties (i.e., absorption and reduced scattering coefficients) from reflected or transmitted light. Such optical parameters, in turn, provide detailed information regarding both the concentrations of clinically relevant chromophores and macroscopic structural variations in tissue. We couple a noncontact optical setup with a simple analysis algorithm to obtain absorption and scattering coefficients of biological samples under test. Technically, a portable picoprojector projects serial sinusoidal patterns at low and high spatial frequencies, while a spectrometer and two independent CCD cameras simultaneously acquire the reflected diffuse light through a single spectrometer and two separate CCD cameras having different bandpass filters at nonisosbestic and isosbestic wavelengths in front of each. This configuration fills the gaps in each other’s capabilities for acquiring optical properties of tissue at high spectral and spatial resolution. Experiments were performed on both tissue-mimicking phantoms as well as hands of healthy human volunteers to quantify their optical properties as proof of concept for the present technique. In a separate experiment, we derived the optical properties of the hand skin from the measured diffuse reflectance, based on a recently developed camera model. Additionally, oxygen saturation levels of tissue measured by the system were found to agree well with reference values. Taken together, the present results demonstrate the potential of this integrated setup for diagnostic and research applications.
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Affiliation(s)
- Daniel Baruch
- Ariel University, Department of Electrical and Electronics Engineering, Ariel, IsraelbAriel University, Department of Physics, Ariel, Israel
| | - David Abookasis
- Ariel University, Department of Electrical and Electronics Engineering, Ariel, Israel
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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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Wilson RH, Vishwanath K, Mycek MA. Optical methods for quantitative and label-free sensing in living human tissues: principles, techniques, and applications. ADVANCES IN PHYSICS 2016; 1:523-543. [PMID: 28824194 PMCID: PMC5560608 DOI: 10.1080/23746149.2016.1221739] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We present an overview of quantitative and label-free optical methods used to characterize living biological tissues, with an emphasis on emerging applications in clinical tissue diagnostics. Specifically, this review focuses on diffuse optical spectroscopy, imaging, and tomography, optical coherence-based techniques, and non-linear optical methods for molecular imaging. The potential for non- or minimally-invasive assessment, quantitative diagnostics, and continuous monitoring enabled by these tissue-optics technologies provides significant promise for continued clinical translation.
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Affiliation(s)
- Robert H. Wilson
- Beckman Laser Institute, University of California, Irvine, Irvine, CA, USA
| | | | - Mary-Ann Mycek
- Department of Biomedical Engineering, Applied Physics Program, University of Michigan, Ann Arbor, MI, USA
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Mora AD, Contini D, Arridge S, Martelli F, Tosi A, Boso G, Farina A, Durduran T, Martinenghi E, Torricelli A, Pifferi A. Towards next-generation time-domain diffuse optics for extreme depth penetration and sensitivity. BIOMEDICAL OPTICS EXPRESS 2015; 6:1749-60. [PMID: 26137377 PMCID: PMC4467698 DOI: 10.1364/boe.6.001749] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 03/20/2015] [Accepted: 03/20/2015] [Indexed: 05/18/2023]
Abstract
Light is a powerful tool to non-invasively probe highly scattering media for clinical applications ranging from oncology to neurology, but also for molecular imaging, and quality assessment of food, wood and pharmaceuticals. Here we show that, for a paradigmatic case of diffuse optical imaging, ideal yet realistic time-domain systems yield more than 2-fold higher depth penetration and many decades higher contrast as compared to ideal continuous-wave systems, by adopting a dense source-detector distribution with picosecond time-gating. Towards this aim, we demonstrate the first building block made of a source-detector pair directly embedded into the probe based on a pulsed Vertical-Cavity Surface-Emitting Laser (VCSEL) to allow parallelization for dense coverage, a Silicon Photomultiplier (SiPM) to maximize light harvesting, and a Single-Photon Avalanche Diode (SPAD) to demonstrate the time-gating capability on the basic SiPM element. This paves the way to a dramatic advancement in terms of increased performances, new high impact applications, and availability of devices with orders of magnitude reduction in size and cost for widespread use, including quantitative wearable imaging.
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Affiliation(s)
- Alberto Dalla Mora
- Dipartimento di Fisica, Politecnico di Milano,
Italy
- These authors contributed equally to this work
| | - Davide Contini
- Dipartimento di Fisica, Politecnico di Milano,
Italy
- These authors contributed equally to this work
| | - Simon Arridge
- Department of Computer Science, University College London,
United Kingdom
| | - Fabrizio Martelli
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze,
Italy
| | - Alberto Tosi
- Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano,
Italy
| | - Gianluca Boso
- Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano,
Italy
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche,
Italy
| | | | | | | | - Antonio Pifferi
- Dipartimento di Fisica, Politecnico di Milano,
Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche,
Italy
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Sun Y, Phipps JE, Meier J, Hatami N, Poirier B, Elson DS, Farwell DG, Marcu L. Endoscopic fluorescence lifetime imaging for in vivo intraoperative diagnosis of oral carcinoma. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:791-8. [PMID: 23702007 PMCID: PMC4128621 DOI: 10.1017/s1431927613001530] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A clinically compatible fluorescence lifetime imaging microscopy (FLIM) system was developed. The system was applied to intraoperative in vivo imaging of head and neck squamous cell carcinoma (HNSCC). The endoscopic FLIM prototype integrates a gated (down to 0.2 ns) intensifier imaging system and a fiber-bundle endoscope (0.5-mm-diameter, 10,000 fibers with a gradient index lens objective 0.5 NA, 4-mm field of view), which provides intraoperative access to the surgical field. Tissue autofluorescence was induced by a pulsed laser (337 nm, 700 ps pulse width) and collected in the 460 ± 25 nm spectral band. FLIM experiments were conducted at 26 anatomic sites in ten patients during head and neck cancer surgery. HNSCC exhibited a weaker florescence intensity (~50% less) when compared with healthy tissue and a shorter average lifetime (τ(HNSCC) = 1.21 ± 0.04 ns) than the surrounding normal tissue (τN = 1.49 ± 0.06 ns). This work demonstrates the potential of FLIM for label-free head and neck tumor demarcation during intraoperative surgical procedures.
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Affiliation(s)
- Yinghua Sun
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Jennifer E. Phipps
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Jeremy Meier
- Department of Otolaryngology-Head and Neck Surgery, University of California Davis, Sacramento, CA 95817, USA
| | - Nisa Hatami
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
| | - Brian Poirier
- Department of Pathology, University of California Davis, Sacramento, CA 95817, USA
| | - Daniel S. Elson
- Department of Surgery, Hamlyn Centre, Imperial College London, London SW7 2AZ, UK
| | - D. Gregory Farwell
- Department of Otolaryngology-Head and Neck Surgery, University of California Davis, Sacramento, CA 95817, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA
- Corresponding author.
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Bargigia I, Tosi A, Bahgat Shehata A, Della Frera A, Farina A, Bassi A, Taroni P, Dalla Mora A, Zappa F, Cubeddu R, Pifferi A. Time-resolved diffuse optical spectroscopy up to 1700 nm by means of a time-gated InGaAs/InP single-photon avalanche diode. APPLIED SPECTROSCOPY 2012; 66:944-50. [PMID: 22800436 DOI: 10.1366/11-06461] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We present a new compact system for time-domain diffuse optical spectroscopy of highly scattering media operating in the wavelength range from 1100 nm to 1700 nm. So far, this technique has been exploited mostly up to 1100 nm: we extended the spectral range by means of a pulsed supercontinuum light source at a high repetition rate, a prism to spectrally disperse the radiation, and a time-gated InGaAs/InP single-photon avalanche diode working up to 1700 nm. A time-correlated single-photon counting board was used as processing electronics. The system is characterized by linear behavior up to absorption values of about 3.4 cm(-1) where the relative error is 17%. A first measurement performed on lipids is presented: the absorption spectrum shows three major peaks at 1200 nm, 1400 nm, and 1700 nm.
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Affiliation(s)
- Ilaria Bargigia
- Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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Nachabé R, Hendriks BHW, van der Voort M, Desjardins AE, Sterenborg HJCM. Estimation of biological chromophores using diffuse optical spectroscopy: benefit of extending the UV-VIS wavelength range to include 1000 to 1600 nm. BIOMEDICAL OPTICS EXPRESS 2010; 1:1432-1442. [PMID: 21258560 PMCID: PMC3018130 DOI: 10.1364/boe.1.001432] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 10/28/2010] [Accepted: 11/16/2010] [Indexed: 05/19/2023]
Abstract
With an optical fiber probe, we acquired spectra from swine tissue between 500 and 1600 nm by combining a silicon and an InGaAs spectrometer. The concentrations of the biological chromophores were estimated by fitting a mathematical model derived from diffusion theory. The advantage of our technique relative to those presented in previous studies is that we extended the commonly-used wavelength ranges of 500 and 1000 nm to include the range of 1000 to 1600 nm, where additional water and lipid absorption features exist. Hence, a more accurate estimation of these two chromophores is expected when spectra are fitted between 500 and 1600 nm than between 500 and 1000 nm. When extending the UV-VIS wavelength range, the estimated total amount of chromophores approached 100% of the total as present in the probed volume. The confidence levels of the water and lipid related parameters increases by a factor of four.
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Affiliation(s)
- Rami Nachabé
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Benno H. W. Hendriks
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Marjolein van der Voort
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Adrien E. Desjardins
- Department of Minimally Invasive Healthcare, Philips Research, 5656 AE Eindhoven,The Netherlands
| | - Henricus J. C. M. Sterenborg
- Department of Radiation Oncology,Center of Optical Diagnostics and Therapy,Erasmus Medical Center,3008 AE Rotterdam,The Netherlands
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10
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Guan Z, Lundin P, Svanberg S. Assessment of photon migration in scattering media using heterodyning techniques with a frequency modulated diode laser. OPTICS EXPRESS 2009; 17:16291-9. [PMID: 19724628 DOI: 10.1364/oe.17.016291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A novel technique for studying photon propagation in scattering media is proposed and demonstrated, as is believed, for the first time. Photons propagating through the medium, from a frequency-ramped single-mode diode laser, meet a reference beam from the same source, at a common detector, and beat frequencies corresponding to various temporal delays are observed by heterodyne techniques. Fourier transformation directly yields the temporal dispersion curve. Proof-of-principle experiments on polystyrene foam and a tissue phantom suggest, that the new method, when fully developed, may favorably compete with the more complex time-correlated single-photon counting (TCSPC) and the phase-shift methods, now much employed.
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Affiliation(s)
- Zuguang Guan
- Atomic Physics Division, Lund University, P.O. Box 118, S-22100 Lund, Sweden.
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11
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Farina A, Bassi A, Pifferi A, Taroni P, Comelli D, Spinelli L, Cubeddu R. Bandpass effects in time-resolved diffuse spectroscopy. APPLIED SPECTROSCOPY 2009; 63:48-56. [PMID: 19146718 DOI: 10.1366/000370209787169795] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
This paper discusses the spectral distortions occurring when time-resolved spectroscopy of diffusive media is performed illuminating with a wide bandpass. It is shown that the spectral region within the bandpass that exhibits the lowest absorption will dominate the resulting time-resolved curve, leading to significant underestimations of absorption as well as distortions in the spectral shape (including shifts in peak positions). Due to the nonlinear behavior of absorption, this effect becomes even more pronounced when including longer and longer photon path lengths. First, a theoretical treatment of the problem is given, and then the distortion is described by time-resolved reflectance simulations and experimental measurements of lipid and water samples. A spectrally constrained data analysis is proposed that takes into account the spectrum of the light injected into the sample, used to overcome the distortion and improve the accuracy of the estimation of chromophore concentrations from absorption spectra. Measurements on a lipid sample show a reduction of the error from 30% to 6%.
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Affiliation(s)
- A Farina
- IIT, CNR-INFM and CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
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12
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Johansson J, Berg R, Pifferi A, Svanberg S, Björn LO. Time-Resolved Studies of Light Propagation in Crassula and Phaseolus Leaves. Photochem Photobiol 2008; 69:242-247. [DOI: 10.1111/j.1751-1097.1999.tb03281.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Zhu D, Lu W, Zeng S, Luo Q. Effect of light losses of sample between two integrating spheres on optical properties estimation. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:064004. [PMID: 18163820 DOI: 10.1117/1.2815691] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A Monte Carlo algorithm is applied to simulate the measurements of a sample with glass slides sandwiched between the double integrating sphere (DIS) setup. The effects caused by various parameters, such as the sample port of integrating sphere, thicknesses, and optical properties of the sample, on light losses and optical properties estimated by the inverse adding-doubling method (IAD) have been investigated. The results show that the light loss greatly increases the estimated error of absorption coefficient and slightly affects the estimated scattering coefficient. When the increase of apparent absorption of the sample induced by the light loss is 59%, the relative error of the scattering coefficient is less than 2% and that of the absorption coefficient reaches 28%. Enhancing the sample port diameter or decreasing the thickness of the sample can reduce the error effectively, and the effect of the former is much greater than that of the latter. In addition, the IAD method is proved to be valid for estimating the optical properties of a highly scattering or highly absorbing sample. This study can not only evaluate the error of optical properties estimation, but also provide optimal ways for the design of DIS and a scheme for acquiring accurate optical properties of tissue.
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Affiliation(s)
- Dan Zhu
- Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, 430074, China
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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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15
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Chauchard F, Roussel S, Roger JM, Bellon-Maurel V, Abrahamsson C, Svensson T, Andersson-Engels S, Svanberg S. Least-squares support vector machines modelization for time-resolved spectroscopy. APPLIED OPTICS 2005; 44:7091-7. [PMID: 16318179 DOI: 10.1364/ao.44.007091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
By use of time-resolved spectroscopy it is possible to separate light scattering effects from chemical absorption effects in samples. In the study of propagation of short light pulses in turbid samples the reduced scattering coefficient and the absorption coefficient are usually obtained by fitting diffusion or Monte Carlo models to the measured data by use of numerical optimization techniques. In this study we propose a prediction model obtained with a semiparametric modeling technique: the least-squares support vector machines. The main advantage of this technique is that it uses theoretical time dispersion curves during the calibration step. Predictions can then be performed by use of data measured on different kinds of sample, such as apples.
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Affiliation(s)
- Fabien Chauchard
- Information and Technologies for Agro-processes Cemagref, BP 5095, 34033 Montpellier, Cedex 1, France.
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16
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Ramstein S, Vignal C, Mathevon N, Mottin S. In vivo and noninvasive measurement of a songbird head's optical properties. APPLIED OPTICS 2005; 44:6197-204. [PMID: 16237935 DOI: 10.1364/ao.44.006197] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
By assessing the cerebral blood volume and the hemoglobin oxygen saturation level, near-infrared spectroscopy (NIRS) probes brain oxygenation, which reflects cerebral activity. To develop a noninvasive method monitoring the brain of a songbird, we use an original NIRS device, i.e., a white laser coupled with an ultrafast spectrotemporal detector of optical signals without wavelength scanning. We perform in vivo measurements of the absorption coefficient and the reduced scattering coefficient of the caudal nidopallium area of the head of a songbird (the zebra finch).
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Affiliation(s)
- Stéphane Ramstein
- Laboratoire Traitement du Signal et Instrumentation, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5516, Université Jean Monnet, Saint-Etienne, France
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17
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Swartling J, Bassi A, D'Andrea C, Pifferi A, Torricelli A, Cubeddu R. Dynamic time-resolved diffuse spectroscopy based on supercontinuum light pulses. APPLIED OPTICS 2005; 44:4684-92. [PMID: 16075881 DOI: 10.1364/ao.44.004684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We present a detailed characterization of a system for fast time-resolved spectroscopy of turbid media based on supercontinuum generation in a photonic crystal fiber. The light source provides subpicosecond pulses in the 550-1000-nm spectral range, at 85 MHz, at an average power of up to 50 mW. Wavelength-resolved detection is accomplished by means of a spectrometer coupled to a 16-channel, multianode photomultiplier tube, giving a resolution of 4.5-35 nm/channel, depending on the grating. Time-dispersion curves are acquired with time-correlated single-photon counting, and absorption and reduced scattering coefficients are determined by fitting the data to the diffusion equation. We characterized the system by measuring the time-resolved diffuse reflectance of epoxy phantoms and by assessing the performance in terms of accuracy, linearity, noise sensitivity, stability, and reproducibility. The results were similar to those from previous systems, whereas the full-spectrum (610-810 nm) acquisition time was as short as 1 s owing to the parallel acquisition. We also present the first in vivo real-time dynamic spectral measurements showing tissue oxygenation changes in the arm of a human subject.
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Affiliation(s)
- Johannes Swartling
- ULTRAS-INFM, IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, P. L. da Vinci 32, I-20133 Milano, Italy.
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18
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Bargo PR, Prahl SA, Goodell TT, Sleven RA, Koval G, Blair G, Jacques SL. In vivo determination of optical properties of normal and tumor tissue with white light reflectance and an empirical light transport model during endoscopy. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:034018. [PMID: 16229662 DOI: 10.1117/1.1921907] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Determination of tissue optical properties is fundamental for application of light in either therapeutical or diagnostics procedures. In the present work we implemented a spatially resolved steady-state diffuse reflectance method where only two fibers (one source and one detector) spaced 2.5 mm apart are used for the determination of the optical properties. The method relies on the spectral characteristics of the tissue chromophores (water, dry tissue, and blood) and the assumption of a simple wavelength dependent expression for the determination of the reduced scattering coefficient. Because of the probe dimensions the method is suited for endoscopic measurements. The method was validated against more traditional models, such as the diffusion theory combined with adding doubling for in vitro measurements of bovine muscle. Mean and standard deviation of the absorption coefficient and the reduced scattering coefficient at 630 nm for normal mucosa were 0.87+/-0.22 cm(-1) and 7.8+/-2.3 cm(-1), respectively. Cancerous mucosa had values 1.87+/-1.10 cm(-1) and 8.4+/-2.3 cm(-1), respectively. These values are similar to data presented by other authors. Blood perfusion was the main variable accounting for differences in the absorption coefficient between the studied tissues.
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Affiliation(s)
- P R Bargo
- Oregon Health and Science University, Biomedical Engineering Department, 20000 NW Walker Road,Beaverton, Oregon 97006, USA.
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af Klinteberg C, Pifferi A, Andersson-Engels S, Cubeddu R, Svanberg S. In vivo absorption spectroscopy of tumor sensitizers with femtosecond white light. APPLIED OPTICS 2005; 44:2213-20. [PMID: 15835366 DOI: 10.1364/ao.44.002213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A system based on a femtosecond white-light continuum and a streak camera was used for recordings of the in vivo absorption spectra of the tumor-seeking agent disulphonated aluminum phthalocyanine. Measurements for different drug doses were performed on tumor tissue (muscle-implanted adenocarcinoma) and normal muscle tissue in rats. It was found that the shape of the spectrum is tissue dependent. The peak of the absorption spectrum is blueshifted in tumor tissue as compared with the muscle. Thus the contrast in the drug-related absorption can be altered by up to a factor of 2 from the primary drug molecular-concentration contrast between normal muscle and tumor by the proper selection of the illumination wavelength.
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Bassi A, Swartling J, D'Andrea C, Pifferi A, Torricelli A, Cubeddu R. Time-resolved spectrophotometer for turbid media based on supercontinuum generation in a photonic crystal fiber. OPTICS LETTERS 2004; 29:2405-7. [PMID: 15534962 DOI: 10.1364/ol.29.002405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We describe an instrument for the time-resolved spectroscopy of turbid media that is based on supercontinuum generation in a photonic crystal fiber. The light injected into the sample consists of subpicosecond pulses that cover 550-1000 nm at 85 MHz at an average power of as much as 40 mW. A spectrometer coupled to a multianode photomultiplier tube is used to detect the light simultaneously in 16 wavelength channels, with a resolution of 5-20 nm/channel, depending on the grating. Time-correlated single-photon counting is used to produce time-dispersion curves, which one fits to the diffusion equation to determine absorption and reduced scattering coefficients. We tested the instrument by measuring the time-resolved diffuse reflectance of epoxy phantoms and by performing in vivo measurements on volunteers. The results were similar to those obtained with previous discrete wavelength systems, whereas the full spectrum (610-810 nm) acquisition time was as short as 1 s owing to the parallel acquisition.
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Affiliation(s)
- Andrea Bassi
- National Laboratory for Ultrafast and Ultraintense Optical Science, I-20133 Milan, Italy.
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Torricelli A, Quaresima V, Pifferi A, Biscotti G, Spinelli L, Taroni P, Ferrari M, Cubeddu R. Mapping of calf muscle oxygenation and haemoglobin content during dynamic plantar flexion exercise by multi-channel time-resolved near-infrared spectroscopy. Phys Med Biol 2004; 49:685-99. [PMID: 15070196 DOI: 10.1088/0031-9155/49/5/003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A compact and fast multi-channel time-resolved near-infrared spectroscopy system for tissue oximetry was developed. It employs semiconductor laser and fibre optics for delivery of optical signals. Photons are collected by eight 1 mm fibres and detected by a multianode photomultiplier. A time-correlated single photon counting board is used for the parallel acquisition of time-resolved reflectance curves. Estimate of the reduced scattering coefficient is achieved by fitting with a standard model of diffusion theory, while the modified Lambert-Beer law is used to assess the absorption coefficient. In vivo measurements were performed on five healthy volunteers to monitor spatial changes in calf muscle (medial and lateral gastrocnemius; MG, LG) oxygen saturation (SmO2) and total haemoglobin concentration (tHb) during dynamic plantar flexion exercise performed at 50% of the maximal voluntary contraction. At rest SmO2 was 73.0 +/- 0.9 and 70.5 +/- 1.7% in MG and LG, respectively (P = 0.045). At the end of the exercise, SmO2 decreased (69.1 +/- 1.8 and 63.8 +/- 2.1% in MG and LG, respectively; P < 0.01). The LG desaturation was greater than the MG desaturation (P < 0.02). These results strengthen the role of time-resolved near-infrared spectroscopy as a powerful tool for investigating the spatial and temporal features of muscle SmO2 and tHb.
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Affiliation(s)
- Alessandro Torricelli
- INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, 1-20133 Milan, Italy
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Taroni P, Pifferi A, Torricelli A, Comelli D, Cubeddu R. In vivo absorption and scattering spectroscopy of biological tissues. Photochem Photobiol Sci 2003; 2:124-9. [PMID: 12664972 DOI: 10.1039/b209651j] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Different approaches for absorption and scattering spectroscopy of living tissues are discussed. In particular, a unique system for time-resolved reflectance and transmittance spectroscopy is presented, capable of acquiring in vivo absorption and scattering spectra of diffusive media between 600 and 1000 nm. A review of typical spectra obtained from a variety of tissue structures is shown, including female breast, forearm, abdomen, and forehead. A second-level analysis of the measured spectra permits an estimation of the concentrations of the key tissue absorbers, as well as of the Mie-equivalent scattering radii. Further, absorption and scattering spectra can be used to estimate the penetration depth of light in tissues as a function of wavelength, which is a crucial parameter in view of the possible application of optical in vivo molecular imaging in clinical diagnosis. Finally, an example of the applicability of the methodology to other biological media such as fruits and vegetables is shown.
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Affiliation(s)
- Paola Taroni
- INFM-Dipartimento di Fisica and IFN-CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan, Italy
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Kienle A. Non-invasive determination of muscle blood flow in the extremities from laser Doppler spectra. Phys Med Biol 2001; 46:1231-44. [PMID: 11324962 DOI: 10.1088/0031-9155/46/4/322] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We investigate theoretically the non-invasive determination of blood flow in muscles of the extremities using laser Doppler measurements. Laser Doppler spectra are calculated using Monte Carlo simulations and solutions of the correlation diffusion equation. The extremities are modelled as a two-layered turbid medium. The first layer represents the skin and subcutaneous fat layer and the second layer the muscle. It is shown that the absolute root-mean-square velocity of the blood in the muscle layer can be accurately derived in many practical cases if the laser Doppler spectra are measured at a distance which is sufficiently far from the source, and if the optical properties of the muscle are simultaneously determined.
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Affiliation(s)
- A Kienle
- Institut für Lasertechnologien in der Medizin und Messtechnik, Ulm, Germany
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Dam JS, Pedersen CB, Dalgaard T, Fabricius PE, Aruna P, Andersson-Engels S. Fiber-optic probe for noninvasive real-time determination of tissue optical properties at multiple wavelengths. APPLIED OPTICS 2001; 40:1155-64. [PMID: 18357101 DOI: 10.1364/ao.40.001155] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a compact, fast, and versatile fiber-optic probe system for real-time determination of tissue optical properties from spatially resolved continuous-wave diffuse reflectance measurements. The system collects one set of reflectance data from six source-detector distances at four arbitrary wavelengths with a maximum overall sampling rate of 100 Hz. Multivariate calibration techniques based on two-dimensional polynomial fitting are employed to extract and display the absorption and reduced scattering coefficients in real-time mode. The four wavelengths of the current configuration are 660, 785, 805, and 974 nm, respectively. Cross-validation tests on a 6 x 7 calibration matrix of Intralipid-dye phantoms showed that the mean prediction error at, e.g., 785 nm was 2.8% for the absorption coefficient and 1.3% for the reduced scattering coefficient. The errors are relative to the range of the optical properties of the phantoms at 785 nm, which were 0-0.3/cm for the absorption coefficient and 6-16/cm for the reduced scattering coefficient. Finally, we also present and discuss results from preliminary skin tissue measurements.
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Berg R, Andersson-Engels S, Jarlman O, Svanberg S. Time-gated viewing studies on tissuelike phantoms. APPLIED OPTICS 1996; 35:3432-3440. [PMID: 21102732 DOI: 10.1364/ao.35.003432] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A time-gated technique to enhance viewing through highly scattering media such as tissue is discussed. Experiments have been performed on tissuelike plastic phantoms to determine the possibilities and limitations of the technique. The effects of the time-gate width and the localization, size, and optical properties of hidden objects have been studied. A computer model to simulate light propagation in tissue is also presented. The predictions of the model are compared with experimental results.
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Carlsson J, Hellentin P, Malmqvist L, Persson A, Persson W, Wahlström CG. Time-resolved studies of light propagation in paper. APPLIED OPTICS 1995; 34:1528-1535. [PMID: 21037692 DOI: 10.1364/ao.34.001528] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A method for time-resolved recording of light scattering in thin, highly scattering media is described. Subpicosecond pulses from a high-power Ti:sapphire laser are used, and single-shot recordings of the scattered light are made with a fast streak camera. The method is applied to the study of light scattering in paper, and a 1-ps resolution is demonstrated. The dependence of the light scattering on the basis of weight and density of the paper has been studied. A white-light continuum generated from the high-power pulses by the use of self phase modulation in water is used to study the wavelength dependence of the scattering process. A model for the propagation of light in paper has been developed and used in Monte Carlo simulations. The experimental results are used for testing this model, and absorption and scattering parameters are determined from that comparison.
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