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Katan M, Pearl O, Tzroya A, Duadi H, Fixler D. A Self-Calibrated Single Wavelength Biosensor for Measuring Oxygen Saturation. BIOSENSORS 2024; 14:132. [PMID: 38534239 DOI: 10.3390/bios14030132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/24/2024] [Accepted: 03/01/2024] [Indexed: 03/28/2024]
Abstract
Traditional methods for measuring blood oxygen use multiple wavelengths, which produce an intrinsic error due to ratiometric measurements. These methods assume that the absorption changes with the wavelength, but in fact the scattering changes as well and cannot be neglected. We found that if one measures in a specific angle around a cylindrical tissue, called the iso-pathlength (IPL) point, the reemitted light intensity is unaffected by the tissue's scattering. Therefore, the absorption can be isolated from the scattering, which allows the extraction of the subject's oxygen saturation. In this work, we designed an optical biosensor for reading the light intensity reemitted from the tissue, using a single light source and multiple photodetectors (PDs), with one of them in the IPL point's location. Using this bio-device, we developed a methodology to extract the arterial oxygen saturation using a single wavelength light source. We proved this method is not dependent on the light source and is applicable to different measurement locations on the body, with an error of 0.5%. Moreover, we tested thirty-eight males and females with the biosensor under normal conditions. Finally, we show the results of measuring subjects in a hypoxic chamber that simulates extreme conditions with low oxygen.
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Affiliation(s)
- Michal Katan
- Faculty of Engineering, Bar Ilan University, Ramat Gan 5290002, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Ori Pearl
- Faculty of Engineering, Bar Ilan University, Ramat Gan 5290002, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Alon Tzroya
- Faculty of Engineering, Bar Ilan University, Ramat Gan 5290002, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Hamootal Duadi
- Faculty of Engineering, Bar Ilan University, Ramat Gan 5290002, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Dror Fixler
- Faculty of Engineering, Bar Ilan University, Ramat Gan 5290002, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
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2
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Porous Phantoms Mimicking Tissues-Investigation of Optical Parameters Stability Over Time. MATERIALS 2021; 14:ma14020423. [PMID: 33467152 PMCID: PMC7829841 DOI: 10.3390/ma14020423] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 11/17/2022]
Abstract
Optical phantoms are used to validate optical measurement methods. The stability of their optical parameters over time allows them to be used and stored over long-term periods, while maintaining their optical parameters. The aim of the presented research was to investigate the stability of fabricated porous phantoms, which can be used as a lung phantom in optical system. Measurements were performed in multiple series with an interval of 6 months, recreating the same conditions and using the same measuring system consisting of an integrating sphere, a coherent light source with a wavelength of 635 nm and a detector. Scattering and absorption parameters were determined on the basis of the measured reflectance and transmittance. The tested samples were made of silicone and glycerol in various proportions.
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3
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Feder I, Duadi H, Fixler D. Single wavelength measurements of absorption coefficients based on iso-pathlength point. BIOMEDICAL OPTICS EXPRESS 2020; 11:5760-5771. [PMID: 33149984 PMCID: PMC7587282 DOI: 10.1364/boe.401591] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 05/31/2023]
Abstract
In optical sensing, to reveal the chemical composition of tissues, the main challenge is isolating absorption from scattering. Most techniques use multiple wavelengths, which adds an error due to the optical pathlength differences. We suggest using a unique measurement angle for cylindrical tissues, the iso-pathlength (IPL) point, which depends on tissue geometry only (specifically the effective radius). We present a method for absorption assessment from a single wavelength at multiple measurement angles. The IPL point presented similar optical pathlengths for different tissues, both in simulation and experiments, hence it is optimal. Finally, in vivo measurements validated our proposed method.
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4
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Optical Characterization of Homogeneous and Heterogeneous Intralipid-Based Samples. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10186234] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Different scattering processes take place when photons propagate inside turbid media. Many powerful experimental techniques exploiting these processes have been developed and applied over the years in a large variety of situations from fundamental and applied research to industrial applications. In the present paper, we intend to take advantage of Static Light Scattering (SLS), Dynamic Light Scattering (DLS), and Time-Resolved Transmittance (TRT) for investigating all the different scattering regimes by using scattering suspensions in a very large range of scatterer concentrations. The suspensions were prepared using Intralipid 20%, a material largely employed in studies of the optical properties of turbid media, with concentrations from 10−5% to 50%. By the analysis of the angular and temporal dependence of the scattered light, a more reliable description of the scattering process occurring in these samples can be obtained. TRT measurements allowed us to obtain information on the reduced scattering coefficient, an important parameter largely used in the description of the optical properties of turbid media. TRT was also employed for the detection of inclusions embedded in Intralipid suspensions, by using a properly designed data analysis. The present study allowed us to better elucidate the dependence of scattering properties of Intralipid suspensions in a very large concentration range and the occurrence of the different scattering processes involved in the propagation of light in turbid media for the first time to our knowledge. In so doing, the complementary contribution of SLS, DLS, and TRT in the characterization of turbid media from an optical and structural point of view is strongly evidenced.
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Nanodiamond phantoms mimicking human liver: perspective to calibration of T1 relaxation time in magnetic resonance imaging. Sci Rep 2020; 10:6446. [PMID: 32296116 PMCID: PMC7160200 DOI: 10.1038/s41598-020-63581-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 03/30/2020] [Indexed: 11/21/2022] Open
Abstract
Phantoms of biological tissues are materials that mimic the properties of real tissues. This study shows the development of phantoms with nanodiamond particles for calibration of T1 relaxation time in magnetic resonance imaging. Magnetic resonance imaging (MRI) is a commonly used and non-invasive method of detecting pathological changes inside the human body. Nevertheless, before a new MRI device is approved for use, it is necessary to calibrate it properly and to check its technical parameters. In this article, we present phantoms of tissue with diamond nanoparticles dedicated to magnetic resonance calibration. The method of producing phantoms has been described. As a result of our research, we obtained phantoms that were characterized by the relaxation time T1 the same as the relaxation time of the human tissue T1 = 810.5 ms. Furthermore, the use of diamond nanoparticles in phantoms allowed us to tune the T1 value of the phantoms which open the way to elaborated phantoms of other tissues in the future.
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Duadi H, Feder I, Fixler D. Near-infrared human finger measurements based on self-calibration point: Simulation and in vivo experiments. JOURNAL OF BIOPHOTONICS 2018; 11:e201700208. [PMID: 29131520 DOI: 10.1002/jbio.201700208] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 11/09/2017] [Indexed: 05/26/2023]
Abstract
Near-infrared light allows measuring tissue oxygenation. These measurements relay on oxygenation-dependent absorption spectral changes. However, the tissue scattering, which is also spectral dependent, introduces an intrinsic error. Most methods focus on the volume reflectance from a semi-infinite sample. We have proposed examining the full scattering profile (FSP), which is the angular intensity distribution. A point was found, that is, the iso-path length (IPL) point, which is not dependent on the tissue scattering, and can serve for self-calibration. This point is geometric dependent, hence in cylindrical tissues depends solely on the diameter. In this work, we examine an elliptic tissue cross section via Monte Carlo simulation. We have found that the IPL point of an elliptic tissue cross section is indifferent to the input illumination orientation. Furthermore, the IPL point is the same as in a circular cross section with a radius equal to the effective ellipse radius. This is despite the fact that the FSPs of the circular and elliptical cross sections are different. Hence, changing the orientation of the input illumination reveals the IPL point. In order to demonstrate this experimentally, the FSPs of a few female fingers were measured at 2 perpendicular orientations. The crossing point between these FSPs was found equivalent to the IPL point of a cylindrical phantom with a radius similar to the effective radius. The findings of this work will allow accurate pulse oximetry assessment of blood saturation.
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Affiliation(s)
- Hamootal Duadi
- Faculty of Engineering, Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
| | - Idit Feder
- Faculty of Engineering, Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
| | - Dror Fixler
- Faculty of Engineering, Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
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Feder I, Duadi H, Chakraborty R, Fixler D. Self-Calibration Phenomenon for Near-Infrared Clinical Measurements: Theory, Simulation, and Experiments. ACS OMEGA 2018; 3:2837-2844. [PMID: 30221222 PMCID: PMC6130783 DOI: 10.1021/acsomega.8b00018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/22/2018] [Indexed: 05/13/2023]
Abstract
An irradiated turbid medium scatters the light in accordance to its optical properties. Near-infrared (NIR) clinical methods, which are based on spectral-dependent absorption, suffer from an inherent error due to spectral-dependent scattering. We present here a unique spatial point, that is, iso-pathlength (IPL) point, on the surface of a tissue at which the intensity of re-emitted light remains constant. This scattering-indifferent point depends solely on the medium geometry. On the basis of this natural phenomenon, we suggest a novel optical method for self-calibrated clinical measurements. We found that the IPL point exists in both cylindrical and semi-infinite tissue geometries (Supporting Information, Video file). Finally, in vivo human finger and mice measurements are used to validate the crossing point between the intensity profiles of two wavelengths. Hence, measurements at the IPL point yield an accurate absorption assessment while eliminating the scattering dependence. This finding can be useful for oxygen saturation determination, NIR spectroscopy, photoplethysmography measurements, and a wide range of optical sensing methods for physiological aims.
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Affiliation(s)
- Idit Feder
- Faculty of Engineering and
the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Hamootal Duadi
- Faculty of Engineering and
the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Ruchira Chakraborty
- Faculty of Engineering and
the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Dror Fixler
- Faculty of Engineering and
the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
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8
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Analysis of Flow Cytometric Fluorescence Lifetime with Time-Delay Estimation of Pulse Signals. SENSORS 2018; 18:s18020442. [PMID: 29401636 PMCID: PMC5855028 DOI: 10.3390/s18020442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 02/03/2023]
Abstract
The measurement of fluorescence lifetimes emerged in flow cytometry because it is not impacted by the non-linearity, which occurs in fluorescence intensity measurements. However, this significantly increases the cost and complexity of a traditional flow cytometer. This work reports a simple method of fluorescence lifetime measurement of a flow cytometer based on the cytometric fluorescence pulse time-delay estimation and hardware time-delay calibration. The modified chirp Z-transform (MCZT) algorithm, combined with the algorithm of fine interpolation of correlation peak (FICP), is applied to improve the temporal resolution of the cross-correlation function of the scattering and fluorescence signals, which in turn improves the time-delay estimation accuracy. The estimation accuracy is verified by Gauss fitting. Cells that were labeled simultaneously with three-color reagents are measured; the statistical results of 5000 cells are compared with reference values and are verified with the pulse width variation. The results show the potential of fluorescence lifetime measurements in the traditional flow cytometer.
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Feder I, Wróbel M, Duadi H, Jędrzejewska-Szczerska M, Fixler D. Experimental results of full scattering profile from finger tissue-like phantom. BIOMEDICAL OPTICS EXPRESS 2016; 7:4695-4701. [PMID: 27896008 PMCID: PMC5119608 DOI: 10.1364/boe.7.004695] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/29/2016] [Accepted: 10/14/2016] [Indexed: 05/31/2023]
Abstract
Human tissue is one of the most complex optical media since it is turbid and nonhomogeneous. We suggest a new optical method for sensing physiological tissue state, based on the collection of the ejected light at all exit angles, to receive the full scattering profile. We built a unique set-up for noninvasive encircled measurement. We use a laser, a photodetector and finger tissues-mimicking phantoms presenting different optical properties. Our method reveals an isobaric point, which is independent of the optical properties. We compared the new finger tissues-like phantoms to others samples and found the linear dependence between the isobaric point's angle and the exact tissue geometry. These findings can be useful for biomedical applications such as non-invasive and simple diagnostic of the fingertip joint, ear lobe and pinched tissues.
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Affiliation(s)
- Idit Feder
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Israel
| | - Maciej Wróbel
- Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Metrology and Optoelectronics, Gabriela Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Hamootal Duadi
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Israel
| | - Małgorzata Jędrzejewska-Szczerska
- Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Metrology and Optoelectronics, Gabriela Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
- Senior authors contributed equally
| | - Dror Fixler
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Israel
- Senior authors contributed equally
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Feder I, Duadi H, Dreifuss T, Fixler D. The influence of the blood vessel diameter on the full scattering profile from cylindrical tissues: experimental evidence for the shielding effect. JOURNAL OF BIOPHOTONICS 2016; 9:1001-1008. [PMID: 26663658 DOI: 10.1002/jbio.201500218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/20/2015] [Accepted: 11/10/2015] [Indexed: 06/05/2023]
Abstract
Optical methods for detecting physiological state based on light-tissue interaction are noninvasive, inexpensive, simplistic, and thus very useful. The blood vessels in human tissue are the main cause of light absorbing and scattering. Therefore, the effect of blood vessels on light-tissue interactions is essential for optically detecting physiological tissue state, such as oxygen saturation, blood perfusion and blood pressure. We have previously suggested a new theoretical and experimental method for measuring the full scattering profile, which is the angular distribution of light intensity, of cylindrical tissues. In this work we will present experimental measurements of the full scattering profile of heterogenic cylindrical phantoms that include blood vessels. We show, for the first time that the vessel diameter influences the full scattering profile, and found higher reflection intensity for larger vessel diameters accordance to the shielding effect. For an increase of 60% in the vessel diameter the light intensity in the full scattering profile above 90° is between 9% to 40% higher, depending on the angle. By these results we claim that during respiration, when the blood-vessel diameter changes, it is essential to consider the blood-vessel diameter distribution in order to determine the optical path in tissues. A CT scan of the measured silicon-based phantoms. The phantoms contain the same blood volume in different blood-vessel diameters.
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Affiliation(s)
- Idit Feder
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Hamootal Duadi
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Tamar Dreifuss
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Dror Fixler
- Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, 5290002, Israel.
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Wróbel MS, Popov AP, Bykov AV, Tuchin VV, Jędrzejewska-Szczerska M. Nanoparticle-free tissue-mimicking phantoms with intrinsic scattering. BIOMEDICAL OPTICS EXPRESS 2016; 7:2088-94. [PMID: 27375928 PMCID: PMC4918566 DOI: 10.1364/boe.7.002088] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/16/2016] [Accepted: 04/28/2016] [Indexed: 05/03/2023]
Abstract
We present an alternative to the conventional approach, phantoms without scattering nanoparticles, where scattering is achieved by the material itself: spherical cavities trapped in a silicone matrix. We describe the properties and fabrication of novel optical phantoms based on a silicone elastomer polydimethylsiloxane (PDMS) and glycerol mixture. Optical properties (absorption coefficient µa , reduced scattering coefficient µs' , and anisotropy factor g) of the fabricated phantoms were retrieved from spectrophotometric measurements (in the 400-1100 nm wavelength range) using the inverse adding-doubling method. The internal structure of the phantoms was studied under a scanning electron microscope, and the chemical composition was assessed by Raman spectroscopy. Composition of the phantom material is reported along with the full characterization of the produced phantoms and ways to control their parameters.
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Affiliation(s)
- Maciej S. Wróbel
- Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Metrology and Optoelectronics, Gabriela Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
| | - Alexey P. Popov
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, FI-90014 Oulu, Finland
| | - Alexander V. Bykov
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, FI-90014 Oulu, Finland
| | - Valery V. Tuchin
- University of Oulu, Faculty of Information Technology and Electrical Engineering, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, FI-90014 Oulu, Finland
- Saratov National Research State University, Research-Education Institute of Optics and Biophotonics, 410012 Saratov, Russia
- Institute of Precision Mechanics and Control of Russian Academy of Sciences, 410028 Saratov, Russia
- National Research Tomsk State University, Laboratory of Biophotonics, 634050 Tomsk, Russia
| | - Małgorzata Jędrzejewska-Szczerska
- Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics, Department of Metrology and Optoelectronics, Gabriela Narutowicza Str. 11/12, 80-233 Gdańsk, Poland
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