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Sun Y, Dumont AP, Arefin MS, Patil CA. Model-based characterization platform of fiber optic extended-wavelength diffuse reflectance spectroscopy for identification of neurovascular bundles. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:095002. [PMID: 36088529 PMCID: PMC9463544 DOI: 10.1117/1.jbo.27.9.095002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Fiber-optic extended-wavelength diffuse reflectance spectroscopy (EWDRS) using both visible/near-infrared and shortwave-infrared detectors enables improved detection of spectral absorbances arising from lipids, water, and collagen and has demonstrated promise in a variety of applications, including detection of nerves and neurovascular bundles (NVB). Development of future applications of EWDRS for nerve detection could benefit from the use of model-based analyses including Monte Carlo (MC) simulations and evaluation of agreement between model systems and empirical measurements. AIM The aim of this work is to characterize agreement between EWDRS measurements and simulations and inform future applications of model-based studies of nerve-detecting applications. APPROACH A model-based platform consisting of an ex vivo microsurgical nerve dissection model, unique two-layer optical phantoms, and MC model simulations of fiber-optic EWDRS spectroscopic measurements were used to characterize EWDRS and compare agreement across models. In addition, MC simulations of an EWDRS measurement scenario are performed to provide a representative example of future analyses. RESULTS EWDRS studies performed in the common chicken thigh femoral nerve microsurgical dissection model indicate similar spectral features for classification of NVB versus adjacent tissues as reported in porcine models and human subjects. A comparison of measurements from unique EWDRS issue mimicking optical phantoms and MC simulations indicates high agreement between the two in homogeneous and two-layer optical phantoms, as well as in dissected tissues. Finally, MC simulations of measurement over a simulated NVB indicate the potential of future applications for measurement of nerve plexus. CONCLUSIONS Characterization of agreement between fiber-optic EWDRS measurements and MC simulations demonstrates strong agreement across a variety of tissues and optical phantoms, offering promise for further use to guide the continued development of EWDRS for translational applications.
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Affiliation(s)
- Yu Sun
- Temple University, Department of Bioengineering, Philadelphia, Pennsylvania, United States
| | - Alexander P. Dumont
- Temple University, Department of Bioengineering, Philadelphia, Pennsylvania, United States
| | | | - Chetan A. Patil
- Temple University, Department of Bioengineering, Philadelphia, Pennsylvania, United States
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2
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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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3
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Zhang A, Wu J, Suo J, Fang L, Qiao H, Li DDU, Zhang S, Fan J, Qi D, Dai Q, Pei C. Single-shot compressed ultrafast photography based on U-net network. OPTICS EXPRESS 2020; 28:39299-39310. [PMID: 33379483 DOI: 10.1364/oe.398083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/01/2020] [Indexed: 06/12/2023]
Abstract
The compressive ultrafast photography (CUP) has achieved real-time femtosecond imaging based on the compressive-sensing methods. However, the reconstruction performance usually suffers from artifacts brought by strong noise, aberration, and distortion, which prevents its applications. We propose a deep compressive ultrafast photography (DeepCUP) method. Various numerical simulations have been demonstrated on both the MNIST and UCF-101 datasets and compared with other state-of-the-art algorithms. The result shows that our DeepCUP has a superior performance in both PSNR and SSIM compared to previous compressed-sensing methods. We also illustrate the outstanding performance of the proposed method under system errors and noise in comparison to other methods.
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Kamanli AF, Çetinel G. Comparison of pulse and super pulse radiation modes’ singlet oxygen production effect in antimicrobial photodynamic therapy (AmPDT). Photodiagnosis Photodyn Ther 2020; 30:101706. [DOI: 10.1016/j.pdpdt.2020.101706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/08/2020] [Accepted: 02/28/2020] [Indexed: 10/24/2022]
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Time-Gated Single-Photon Detection in Time-Domain Diffuse Optics: A Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10031101] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This work reviews physical concepts, technologies and applications of time-domain diffuse optics based on time-gated single-photon detection. This particular photon detection strategy is of the utmost importance in the diffuse optics field as it unleashes the full power of the time-domain approach by maximizing performances in terms of contrast produced by a localized perturbation inside the scattering medium, signal-to-noise ratio, measurement time and dynamic range, penetration depth and spatial resolution. The review covers 15 years of theoretical studies, technological progresses, proof of concepts and design of laboratory systems based on time-gated single-photon detection with also few hints on other fields where the time-gated detection strategy produced and will produce further impact.
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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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Kamanli AF, Çetinel G, Yıldız MZ. A New handheld singlet oxygen detection system (SODS) and NIR light source based phantom environment for photodynamic therapy applications. Photodiagnosis Photodyn Ther 2019; 29:101577. [PMID: 31711998 DOI: 10.1016/j.pdpdt.2019.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/02/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
Photodynamic therapy (PDT) is an emerging treatment modality in various areas such as cancer treatment and disinfection. The photosensitizer and oxygen have crucial roles for effective PDT treatment. The quantitative evaluation of singlet oxygen, which is a gold standard for monitoring effective treatment, remains as an important problem for PDT. However, low quantum yield and low life span of the singlet oxygen make the system expensive, unnecessarily large and unadaptable for clinical usage. In our study, a new mobile singlet oxygen detection system (SODS) was designed to detect singlet oxygen illumination during PDT and a new singlet oxygen phantom environment was constituted to test the designed SODS system. The singlet oxygen phantom environment composed of fast switching led driver & microcontroller and led light source (1200-1300 nm radiation). The elements of the singlet oxygen detection system are optic filter and collimation, avalanche photodiode transimpedance amplifier, differential amplifier and a signal processing block. According to the performance evaluation of the system on the phantom environment, the presented SODS can measure the illuminations at 1270 nm wavelength between 10 ns and 15 µs timespans. The results showed that the proposed system might be a good candidate for clinical PDT applications.
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Affiliation(s)
- Ali Furkan Kamanli
- Sakarya University of Applied Sciences, Faculty of Technology, Electrical and Electronics Engineering, Turkey.
| | - Gökçen Çetinel
- Sakarya University, Faculty of Engineering, Electrical and Electronics Engineering, Turkey
| | - Mustafa Zahid Yıldız
- Sakarya University of Applied Sciences, Faculty of Technology, Electrical and Electronics Engineering, Turkey
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8
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Abstract
Time-domain diffuse optical measurement systems determine depth-resolved absorption changes by using the time of flight distribution of the detected photons. It is well known that certain feature data, such as the Laplace transform of the temporal point spread function, is sufficient for image reconstruction and diffuse optical sensing. Conventional time-domain systems require the acquisition of full temporal profiles of diffusive photons and then numerically compute the feature dataset, for example, Laplace transformed intensities for imaging applications. We have proposed a novel method for directly obtaining the Laplace transform data. Our approach can significantly improve the data acquisition speed for time-domain diffuse optical imaging. We also demonstrated that the use of negative Laplace parameters can provide enhanced sensitivity to perturbations located in deep regions.
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Cao S, Zhao Y, ur Rehman S, Feng S, Zuo Y, Li C, Zhang L, Cheng B, Wang Q. Theoretical Studies on InGaAs/InAlAs SAGCM Avalanche Photodiodes. NANOSCALE RESEARCH LETTERS 2018; 13:158. [PMID: 29785568 PMCID: PMC5962483 DOI: 10.1186/s11671-018-2559-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/29/2018] [Indexed: 06/08/2023]
Abstract
In this paper, we provide a detailed insight on InGaAs/InAlAs separate absorption, grading, charge, and multiplication avalanche photodiodes (SAGCM APDs) and a theoretical model of APDs is built. Through theoretical analysis and two-dimensional (2D) simulation, the influence of charge layer and tunneling effect on the APDs is fully understood. The design of charge layer (including doping level and thickness) can be calculated by our predictive model for different multiplication thickness. We find that as the thickness of charge layer increases, the suitable doping level range in charge layer decreases. Compared to thinner charge layer, performance of APD varies significantly via several percent deviations of doping concentrations in thicker charge layer. Moreover, the generation rate (G btt ) of band-to-band tunnel is calculated, and the influence of tunneling effect on avalanche field was analyzed. We confirm that avalanche field and multiplication factor (M n ) in multiplication will decrease by the tunneling effect. The theoretical model and analysis are based on InGaAs/InAlAs APD; however, they are applicable to other APD material systems as well.
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Affiliation(s)
- Siyu Cao
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yue Zhao
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Sajid ur Rehman
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Shuai Feng
- School of Science, Minzu University of China, Beijing, 100081 China
| | - Yuhua Zuo
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Chuanbo Li
- School of Science, Minzu University of China, Beijing, 100081 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Lichun Zhang
- School of Physics and Optoelectronic Engineering, Ludong University, Yantai, 264025 China
| | - Buwen Cheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qiming Wang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083 China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049 China
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Mehta K, Hasnain A, Zhou X, Luo J, Penney TB, Chen N. Spread spectrum time-resolved diffuse optical measurement system for enhanced sensitivity in detecting human brain activity. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:45005. [PMID: 28384708 DOI: 10.1117/1.jbo.22.4.045005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 03/15/2017] [Indexed: 06/07/2023]
Abstract
Diffuse optical spectroscopy (DOS) and imaging methods have been widely applied to noninvasive detection of brain activity. We have designed and implemented a low cost, portable, real-time one-channel time-resolved DOS system for neuroscience studies. Phantom experiments were carried out to test the performance of the system. We further conducted preliminary human experiments and demonstrated that enhanced sensitivity in detecting neural activity in the cortex could be achieved by the use of late arriving photons.
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Affiliation(s)
- Kalpesh Mehta
- National University of Singapore, Department of Biomedical Engineering, Singapore, Singapore
| | - Ali Hasnain
- National University of Singapore, Department of Biomedical Engineering, Singapore, Singapore
| | - Xiaowei Zhou
- National University of Singapore, Department of Biomedical Engineering, Singapore, Singapore
| | - Jianwen Luo
- Tsinghua University, School of Medicine, Department of Biomedical Engineering, Beijing, China
| | - Trevor B Penney
- National University of Singapore, Department of Psychology, Singapore, Singapore
| | - Nanguang Chen
- National University of Singapore, Department of Biomedical Engineering, Singapore, Singapore
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11
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Liang J, Ma C, Zhu L, Chen Y, Gao L, Wang LV. Single-shot real-time video recording of a photonic Mach cone induced by a scattered light pulse. SCIENCE ADVANCES 2017; 3:e1601814. [PMID: 28116357 PMCID: PMC5249257 DOI: 10.1126/sciadv.1601814] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/15/2016] [Indexed: 05/12/2023]
Abstract
Ultrafast video recording of spatiotemporal light distribution in a scattering medium has a significant impact in biomedicine. Although many simulation tools have been implemented to model light propagation in scattering media, existing experimental instruments still lack sufficient imaging speed to record transient light-scattering events in real time. We report single-shot ultrafast video recording of a light-induced photonic Mach cone propagating in an engineered scattering plate assembly. This dynamic light-scattering event was captured in a single camera exposure by lossless-encoding compressed ultrafast photography at 100 billion frames per second. Our experimental results are in excellent agreement with theoretical predictions by time-resolved Monte Carlo simulation. This technology holds great promise for next-generation biomedical imaging instrumentation.
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12
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Amri E, Boso G, Korzh B, Zbinden H. Temporal jitter in free-running InGaAs/InP single-photon avalanche detectors. OPTICS LETTERS 2016; 41:5728-5731. [PMID: 27973517 DOI: 10.1364/ol.41.005728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Negative-feedback avalanche diodes (NFADs) provide a practical solution for different single-photon counting applications requiring free-running mode operation with low afterpulsing probability. Unfortunately, the timing jitter has never been as good as for gated InGaAs/InP single-photon avalanche diodes. Here we report on the timing jitter characterization of InGaAs/InP based NFADs with particular focus on the temperature dependence and the effect of carrier transport between the absorption and multiplication regions. Values as low as 52 ps full-width at half-maximum were obtained at an excess bias voltage of 3.5 V and an operating temperature of around -100°C.
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13
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Zhang H, Salo D, Kim DM, Komarov S, Tai YC, Berezin MY. Penetration depth of photons in biological tissues from hyperspectral imaging in shortwave infrared in transmission and reflection geometries. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:126006. [PMID: 27930773 PMCID: PMC5147011 DOI: 10.1117/1.jbo.21.12.126006] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/11/2016] [Indexed: 05/20/2023]
Abstract
Measurement of photon penetration in biological tissues is a central theme in optical imaging. A great number of endogenous tissue factors such as absorption, scattering, and anisotropy affect the path of photons in tissue, making it difficult to predict the penetration depth at different wavelengths. Traditional studies evaluating photon penetration at different wavelengths are focused on tissue spectroscopy that does not take into account the heterogeneity within the sample. This is especially critical in shortwave infrared where the individual vibration-based absorption properties of the tissue molecules are affected by nearby tissue components. We have explored the depth penetration in biological tissues from 900 to 1650 nm using Monte–Carlo simulation and a hyperspectral imaging system with Michelson spatial contrast as a metric of light penetration. Chromatic aberration-free hyperspectral images in transmission and reflection geometries were collected with a spectral resolution of 5.27 nm and a total acquisition time of 3 min. Relatively short recording time minimized artifacts from sample drying. Results from both transmission and reflection geometries consistently revealed that the highest spatial contrast in the wavelength range for deep tissue lies within 1300 to 1375 nm; however, in heavily pigmented tissue such as the liver, the range 1550 to 1600 nm is also prominent.
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Affiliation(s)
- Hairong Zhang
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Daniel Salo
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - David M. Kim
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Sergey Komarov
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Yuan-Chuan Tai
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Mikhail Y. Berezin
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Address all correspondence to: Mikhail Y. Berezin, E-mail:
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14
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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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15
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Guggenheim JA, Bargigia I, Farina A, Pifferi A, Dehghani H. Time resolved diffuse optical spectroscopy with geometrically accurate models for bulk parameter recovery. BIOMEDICAL OPTICS EXPRESS 2016; 7:3784-3794. [PMID: 27699137 PMCID: PMC5030049 DOI: 10.1364/boe.7.003784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 05/04/2023]
Abstract
A novel straightforward, accessible and efficient approach is presented for performing hyperspectral time-domain diffuse optical spectroscopy to determine the optical properties of samples accurately using geometry specific models. To allow bulk parameter recovery from measured spectra, a set of libraries based on a numerical model of the domain being investigated is developed as opposed to the conventional approach of using an analytical semi-infinite slab approximation, which is known and shown to introduce boundary effects. Results demonstrate that the method improves the accuracy of derived spectrally varying optical properties over the use of the semi-infinite approximation.
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Affiliation(s)
- James A. Guggenheim
- PSIBS Doctoral Training Centre, University of Birmingham, Birmingham, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Ilaria Bargigia
- Center for Nano-Science and Technology @POLIMI, Istituto Italiano di Tecnologia, Milano, Italy
| | - Andrea Farina
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Milano, Italy
| | - Antonio Pifferi
- Consiglio Nazionale delle Ricerche, Istituto di Fotonica e Nanotecnologie, Milano, Italy
- Politecnico di Milano, Dipartimento di Fisica, Milano, Italy
| | - Hamid Dehghani
- PSIBS Doctoral Training Centre, University of Birmingham, Birmingham, UK
- School of Computer Science, University of Birmingham, Birmingham, UK
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16
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Martinenghi E, Di Sieno L, Contini D, Sanzaro M, Pifferi A, Dalla Mora A. Time-resolved single-photon detection module based on silicon photomultiplier: A novel building block for time-correlated measurement systems. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:073101. [PMID: 27475542 DOI: 10.1063/1.4954968] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 06/16/2016] [Indexed: 05/20/2023]
Abstract
We present the design and preliminary characterization of the first detection module based on Silicon Photomultiplier (SiPM) tailored for single-photon timing applications. The aim of this work is to demonstrate, thanks to the design of a suitable module, the possibility to easily exploit SiPM in many applications as an interesting detector featuring large active area, similarly to photomultipliers tubes, but keeping the advantages of solid state detectors (high quantum efficiency, low cost, compactness, robustness, low bias voltage, and insensitiveness to magnetic field). The module integrates a cooled SiPM with a total photosensitive area of 1 mm(2) together with the suitable avalanche signal read-out circuit, the signal conditioning, the biasing electronics, and a Peltier cooler driver for thermal stabilization. It is able to extract the single-photon timing information with resolution better than 100 ps full-width at half maximum. We verified the effective stabilization in response to external thermal perturbations, thus proving the complete insensitivity of the module to environment temperature variations, which represents a fundamental parameter to profitably use the instrument for real-field applications. We also characterized the single-photon timing resolution, the background noise due to both primary dark count generation and afterpulsing, the single-photon detection efficiency, and the instrument response function shape. The proposed module can become a reliable and cost-effective building block for time-correlated single-photon counting instruments in applications requiring high collection capability of isotropic light and detection efficiency (e.g., fluorescence decay measurements or time-domain diffuse optics systems).
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Affiliation(s)
- E Martinenghi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - L Di Sieno
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - D Contini
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - M Sanzaro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - A Pifferi
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - A Dalla Mora
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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Boso G, Ke D, Korzh B, Bouilloux J, Lange N, Zbinden H. Time-resolved singlet-oxygen luminescence detection with an efficient and practical semiconductor single-photon detector. BIOMEDICAL OPTICS EXPRESS 2016; 7:211-24. [PMID: 26819830 PMCID: PMC4722905 DOI: 10.1364/boe.7.000211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/17/2015] [Accepted: 12/17/2015] [Indexed: 05/03/2023]
Abstract
In clinical applications, such as PhotoDynamic Therapy, direct singlet-oxygen detection through its luminescence in the near-infrared range (1270 nm) has been a challenging task due to its low emission probability and the lack of suitable single-photon detectors. Here, we propose a practical setup based on a negative-feedback avalanche diode detector that is a viable alternative to the current state-of-the art for different clinical scenarios, especially where geometric collection efficiency is limited (e.g. fiber-based systems, confocal microscopy, scanning systems etc.). The proposed setup is characterized with Rose Bengal as a standard photosensitizer and it is used to measure the singlet-oxygen quantum yield of a new set of photosensitizers for site-selective photodynamic therapy.
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Affiliation(s)
- Gianluca Boso
- Group of Applied Physics, University of Geneva, Chemin de Pinchat 22, Genève 4, CH-1211, Switzerland
| | - Damei Ke
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest Ansermet 30, Genève 4, CH-1211, Switzerland
| | - Boris Korzh
- Group of Applied Physics, University of Geneva, Chemin de Pinchat 22, Genève 4, CH-1211, Switzerland
| | - Jordan Bouilloux
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest Ansermet 30, Genève 4, CH-1211, Switzerland
| | - Norbert Lange
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest Ansermet 30, Genève 4, CH-1211, Switzerland
| | - Hugo Zbinden
- Group of Applied Physics, University of Geneva, Chemin de Pinchat 22, Genève 4, CH-1211, Switzerland
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Zhang B, Jin A, Ma P, Chen S, Hou J. High-power near-infrared linearly-polarized supercontinuum generation in a polarization-maintaining Yb-doped fiber amplifier. OPTICS EXPRESS 2015; 23:28683-28690. [PMID: 26561136 DOI: 10.1364/oe.23.028683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report an all-fiber linearly-polarized (LP) supercontinuum (SC) source with high average power generated in a polarization-maintaining (PM) master-oscillation power-amplifier (MOPA). The experimental configuration comprises an LP picosecond pulsed laser and three PM Yd-doped fiber amplifiers (YDFA). The output has the average power of 124.8 W with the spectrum covering from 850 to 1900 nm. The measured polarization extinction ratio (PER) of the whole SC source is about 85% which verifies the SC an LP source. This work is, to our best knowledge, the highest output average power of an LP SC source that ever reported. The influence of PM fiber splicing method on the LP SC property is investigated by splicing the PM fibers with slow axis parallel or perpendicularly aligned, and also an LP SC with low output power is demonstrated.
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19
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Farina A, Torricelli A, Bargigia I, Spinelli L, Cubeddu R, Foschum F, Jäger M, Simon E, Fugger O, Kienle A, Martelli F, Di Ninni P, Zaccanti G, Milej D, Sawosz P, Kacprzak M, Liebert A, Pifferi A. In-vivo multilaboratory investigation of the optical properties of the human head. BIOMEDICAL OPTICS EXPRESS 2015. [PMID: 26203385 PMCID: PMC4505713 DOI: 10.1364/boe.6.002609] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The in-vivo optical properties of the human head are investigated in the 600-1100 nm range on different subjects using continuous wave and time domain diffuse optical spectroscopy. The work was performed in collaboration with different research groups and the different techniques were applied to the same subject. Data analysis was carried out using homogeneous and layered models and final results were also confirmed by Monte Carlo simulations. The depth sensitivity of each technique was investigated and related to the probed region of the cerebral tissue. This work, based on different validated instruments, is a contribution to fill the existing gap between the present knowledge and the actual in-vivo values of the head optical properties.
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Affiliation(s)
- Andrea Farina
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
| | - Alessandro Torricelli
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
| | - Ilaria Bargigia
- Center for Nano-Science and Technology @POLIMI, Istituto Italiano di Tecnologia, via G. Pascoli 70/3, 20133 Milano,
Italy
| | - Lorenzo Spinelli
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
| | - Rinaldo Cubeddu
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
| | - Florian Foschum
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Marion Jäger
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Emanuel Simon
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Oliver Fugger
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Alwin Kienle
- ILM, Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, Helmholtzstraße 12, D-89081 Ulm,
Germany
| | - Fabrizio Martelli
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Paola Di Ninni
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Giovanni Zaccanti
- UNIFI, Università degli Studi di Firenze - Dipartimento di Fisica e Astronomia, Via G. Sansone, N. 1, 50019 Sesto Fiorentino, Firenze,
Italy
| | - Daniel Milej
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Piotr Sawosz
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Michał Kacprzak
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Adam Liebert
- IBIB, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw,
Poland
| | - Antonio Pifferi
- Consiglio Nazionale delle Ricerche - Istituto di Fotonica e Nanotecnologie, Piazza L. da Vinci 32, I-20133 Milano,
Italy
- POLIMI, Politecnico di Milano, Dipartimento di Fisica, Piazza L. Da Vinci 32, I-20133 Milano,
Italy
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20
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Wilson RH, Nadeau KP, Jaworski FB, Tromberg BJ, Durkin AJ. Review of short-wave infrared spectroscopy and imaging methods for biological tissue characterization. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:030901. [PMID: 25803186 PMCID: PMC4370890 DOI: 10.1117/1.jbo.20.3.030901] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/24/2015] [Indexed: 05/18/2023]
Abstract
We present a review of short-wave infrared (SWIR, defined here as ∼1000 to 2000 nm) spectroscopy and imaging techniques for biological tissue optical property characterization. Studies indicate notable SWIR absorption features of tissue constituents including water (near 1150, 1450, and 1900 nm), lipids (near 1040, 1200, 1400, and 1700 nm), and collagen (near 1200 and 1500 nm) that are much more prominent than corresponding features observed in the visible and near-infrared (VIS-NIR, defined here as ∼400 to 1000 nm). Furthermore, the wavelength dependence of the scattering coefficient has been observed to follow a power-law decay from the VIS-NIR to the SWIR region. Thus, the magnitude of tissue scattering is lower at SWIR wavelengths than that observed at VIS or NIR wavelengths, potentially enabling increased penetration depth of incident light at SWIR wavelengths that are not highly absorbed by the aforementioned chromophores. These aspects of SWIR suggest that the tissue spectroscopy and imaging in this range of wavelengths have the potential to provide enhanced sensitivity (relative to VIS-NIR measurements) to chromophores such as water and lipids, thereby helping to characterize changes in the concentrations of these chromophores due to conditions such as atherosclerotic plaque, breast cancer, and burns.
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Affiliation(s)
- Robert H. Wilson
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Kyle P. Nadeau
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Frank B. Jaworski
- Raytheon Vision Systems, 75 Coromar Drive, Goleta, California 93117, United Sates
| | - Bruce J. Tromberg
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Anthony J. Durkin
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, United States
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21
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Kamran F, Abildgaard OHA, Sparén A, Svensson O, Johansson J, Andersson-Engels S, Andersen PE, Khoptyar D. Transmission near-infrared (NIR) and photon time-of-flight (PTOF) spectroscopy in a comparative analysis of pharmaceuticals. APPLIED SPECTROSCOPY 2015; 69:389-397. [PMID: 25664562 DOI: 10.1366/14-07530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a comprehensive study of the application of photon time-of-flight spectroscopy (PTOFS) in the wavelength range 1050-1350 nm as a spectroscopic technique for the evaluation of the chemical composition and structural properties of pharmaceutical tablets. PTOFS is compared to transmission near-infrared spectroscopy (NIRS). In contrast to transmission NIRS, PTOFS is capable of directly and independently determining the absorption and reduced scattering coefficients of the medium. Chemometric models were built on the evaluated absorption spectra for predicting tablet drug concentration. Results are compared to corresponding predictions built on transmission NIRS measurements. The predictive ability of PTOFS and transmission NIRS is comparable when models are based on uniformly distributed tablet sets. For non-uniform distribution of tablets based on particle sizes, the prediction ability of PTOFS is better than that of transmission NIRS. Analysis of reduced scattering spectra shows that PTOFS is able to characterize tablet microstructure and manufacturing process parameters. In contrast to the chemometric pseudo-variables provided by transmission NIRS, PTOFS provides physically meaningful quantities such as scattering strength and slope of particle size. The ability of PTOFS to quantify the reduced scattering spectra, together with its robustness in predicting drug content, makes it suitable for such evaluations in the pharmaceutical industry.
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Affiliation(s)
- Faisal Kamran
- Department of Photonics Engineering, Technical University of Denmark, Frederiksborg 399, 4000 Denmark
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22
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Lemaillet P, Bouchard JP, Hwang J, Allen DW. Double-integrating-sphere system at the National Institute of Standards and Technology in support of measurement standards for the determination of optical properties of tissue-mimicking phantoms. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:121310. [PMID: 26505172 DOI: 10.1117/1.jbo.20.12.121310] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/29/2015] [Indexed: 05/22/2023]
Abstract
There is a need for a common reference point that will allow for the comparison of the optical properties of tissue-mimicking phantoms. After a brief review of the methods that have been used to measure the phantoms for a contextual backdrop to our approach, this paper reports on the establishment of a standardized double-integrating-sphere platform to measure absorption and reduced scattering coefficients of tissue-mimicking biomedical phantoms. The platform implements a user-friendly graphical user interface in which variations of experimental configurations and model-based analysis are implemented to compute the coefficients based on a modified inverse adding-doubling algorithm allowing a complete uncertainty evaluation. Repeatability and validation of the measurement results of solid phantoms are demonstrated for three samples of different thicknesses, d = 5.08 mm, 7.09 mm, and 9.92 mm, with an absolute error estimate of 4.0% to 5.0% for the absorption coefficient and 11% to 12% for the reduced scattering coefficient (k = 2). The results are in accordance with those provided by the manufacturer. Measurements with different polarization angles of the incident light are also presented, and the resulting optical properties were determined to be equivalent within the estimated uncertainties.
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Affiliation(s)
- Paul Lemaillet
- National Institute of Standards and Technology, Physical Measurement Laboratory, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
| | | | - Jeeseong Hwang
- National Institute of Standards and Technology, Physical Measurement Laboratory, 325 Broadway Street, Boulder, Colorado 80305, United States
| | - David W Allen
- National Institute of Standards and Technology, Physical Measurement Laboratory, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States
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23
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Wilson RH, Nadeau KP, Jaworski FB, Rowland R, Nguyen JQ, Crouzet C, Saager RB, Choi B, Tromberg BJ, Durkin AJ. Quantitative short-wave infrared multispectral imaging of in vivo tissue optical properties. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:086011. [PMID: 25120175 PMCID: PMC4407665 DOI: 10.1117/1.jbo.19.8.086011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/17/2014] [Indexed: 05/04/2023]
Abstract
Extending the wavelength range of spatial frequency domain imaging (SFDI) into the short-wave infrared (SWIR) has the potential to provide enhanced sensitivity to chromophores such as water and lipids that have prominent absorption features in the SWIR region. Here, we present, for the first time, a method combining SFDI with unstructured (zero spatial frequency) illumination to extract tissue absorption and scattering properties over a wavelength range (850 to 1800 nm) largely unexplored by previous tissue optics techniques. To obtain images over this wavelength range, we employ a SWIR camera in conjunction with an SFDI system. We use SFDI to obtain in vivo tissue reduced scattering coefficients at the wavelengths from 850 to 1050 nm, and then use unstructured wide-field illumination and an extrapolated power-law fit to this scattering spectrum to extract the absorption spectrum from 850 to 1800 nm. Our proof-of-principle experiment in a rat burn model illustrates that the combination of multispectral SWIR imaging, SFDI, and unstructured illumination can characterize in vivo changes in skin optical properties over a greatly expanded wavelength range. In the rat burn experiment, these changes (relative to normal, unburned skin) included increased absorption and increased scattering amplitude and slope, consistent with changes that we previously reported in the near-infrared using SFDI.
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Affiliation(s)
- Robert H. Wilson
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Kyle P. Nadeau
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Frank B. Jaworski
- Raytheon Vision Systems, 75 Coromar Drive, Goleta, California 93117, United States
| | - Rebecca Rowland
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - John Q. Nguyen
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Christian Crouzet
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Rolf B. Saager
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Bernard Choi
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Bruce J. Tromberg
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
| | - Anthony J. Durkin
- University of California, Beckman Laser Institute, Irvine, 1002 Health Sciences Road, Irvine, California 92612, United States
- Address all correspondence to: Anthony J. Durkin, E-mail:
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24
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Abstract
Diffuse optical imaging is highly versatile and has a very broad range of applications in biology and medicine. It covers diffuse optical tomography, fluorescence diffuse optical tomography, bioluminescence, and a number of other new imaging methods. These methods of diffuse optical imaging have diversified instrument configurations but share the same core physical principle – light propagation in highly diffusive media, i.e., the biological tissue. In this review, the author summarizes the latest development in instrumentation and methodology available to diffuse optical imaging in terms of system architecture, light source, photo-detection, spectral separation, signal modulation, and lastly imaging contrast.
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25
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Svensson T, Vynck K, Adolfsson E, Farina A, Pifferi A, Wiersma DS. Light diffusion in quenched disorder: role of step correlations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:022141. [PMID: 25353456 DOI: 10.1103/physreve.89.022141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Indexed: 06/04/2023]
Abstract
We present a theoretical and experimental study of light transport in disordered media with strongly heterogeneous distribution of scatterers formed via nonscattering regions. Step correlations induced by quenched disorder are found to prevent diffusivity from diverging with increasing heterogeneity scale, contrary to expectations from annealed models. Spectral diffusivity is measured for a porous ceramic where nanopores act as scatterers and macropores render their distribution heterogeneous. Results agree well with Monte Carlo simulations and a proposed analytical model.
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Affiliation(s)
- Tomas Svensson
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Kevin Vynck
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy and Institut Langevin, ESPCI ParisTech, CNRS, 1 rue Jussieu, 75238 Paris Cedex 05, France
| | - Erik Adolfsson
- Ceramic Materials, SWEREA IVF, Post Office Box 104, SE- 431 22 Mölndal, Sweden
| | - Andrea Farina
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Piazza Leonardo da Vinci 32, Milan 20133, Italy
| | - Antonio Pifferi
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Piazza Leonardo da Vinci 32, Milan 20133, Italy and Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan 20133, Italy
| | - Diederik S Wiersma
- European Laboratory for Non-linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy and Istituto Nazionale di Ottica (CNR-INO), Largo Fermi 6, 50125 Firenze, Italy
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26
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Farina A, Bargigia I, Janeček ER, Walsh Z, D'Andrea C, Nevin A, Ramage M, Scherman OA, Pifferi A. Nondestructive optical detection of monomer uptake in wood polymer composites. OPTICS LETTERS 2014; 39:228-31. [PMID: 24562113 DOI: 10.1364/ol.39.000228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A noninvasive method to assess the local monomer concentration within a wooden matrix, post monomer impregnation, by time-resolved diffuse optical spectroscopy is demonstrated. A data analysis technique for improving accuracy, which takes account of changes in the refractive index during the monomer uptake, has been employed. This technique can be potentially applied in the wood industry for the study of polymer composites as well as in cultural heritage science for noninvasively monitoring the penetration of chemical compounds used for consolidation or conservation purposes.
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27
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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: 7] [Impact Index Per Article: 0.6] [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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