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Fan S, Yu H, Guan Z, Lv F, Zhou Z, Dai C. Diagnosis of dental caries based on attenuation coefficients analysis of optical coherence tomography images. JOURNAL OF BIOPHOTONICS 2024; 17:e202400031. [PMID: 38877707 DOI: 10.1002/jbio.202400031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 06/16/2024]
Abstract
Quantitative analysis of optical attenuation based on optical coherence tomography images will offer an effective method to enhance diagnostic capabilities. In this paper, the optical attenuation in demineralized caries specimens was calculated to distinguish between normal teeth and carious teeth and further to differentiate the severity of caries, and thus come to the half-automated diagnosis of dental caries. Results show that the attenuation coefficient in carious regions is approximately 4.97 mm - 1 ± 0.206 , while that of normal teeth is about 3.69 mm - 1 ± 0.231 . Attenuation coefficient of carious regions is 35% higher than that of normal teeth. Moreover, five classes of caries were qualified and classified based on the optical attenuation coefficient. Compared with the healthy teeth, there is a noticeable disparity in the attenuation coefficients of carious teeth, both on the surface and at the dentinoenamel junction. This study provides a method for accurate caries diagnosis, particularly in detection of early lesions and subtle structural changes.
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Affiliation(s)
- Shuhao Fan
- Shanghai Institute of Technology, College of Sciences, Shanghai, China
| | - Huanhuan Yu
- Shanghai Institute of Technology, College of Sciences, Shanghai, China
| | - Zehua Guan
- Shanghai Institute of Technology, College of Sciences, Shanghai, China
| | - Fukang Lv
- Shanghai Institute of Technology, College of Sciences, Shanghai, China
| | - Zhuojun Zhou
- Department of General Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Shanghai, China
| | - Cuixia Dai
- Shanghai Institute of Technology, College of Sciences, Shanghai, China
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Wolff LI, Hachgenei E, Goßmann P, Druzenko M, Frye M, König N, Schmitt RH, Chrysos A, Jöchle K, Truhn D, Kather JN, Lambertz A, Gaisa NT, Jonigk D, Ulmer TF, Neumann UP, Lang SA, Amygdalos I. Optical coherence tomography combined with convolutional neural networks can differentiate between intrahepatic cholangiocarcinoma and liver parenchyma ex vivo. J Cancer Res Clin Oncol 2023; 149:7877-7885. [PMID: 37046121 PMCID: PMC10374764 DOI: 10.1007/s00432-023-04742-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/02/2023] [Indexed: 04/14/2023]
Abstract
PURPOSE Surgical resection with complete tumor excision (R0) provides the best chance of long-term survival for patients with intrahepatic cholangiocarcinoma (iCCA). A non-invasive imaging technology, which could provide quick intraoperative assessment of resection margins, as an adjunct to histological examination, is optical coherence tomography (OCT). In this study, we investigated the ability of OCT combined with convolutional neural networks (CNN), to differentiate iCCA from normal liver parenchyma ex vivo. METHODS Consecutive adult patients undergoing elective liver resections for iCCA between June 2020 and April 2021 (n = 11) were included in this study. Areas of interest from resection specimens were scanned ex vivo, before formalin fixation, using a table-top OCT device at 1310 nm wavelength. Scanned areas were marked and histologically examined, providing a diagnosis for each scan. An Xception CNN was trained, validated, and tested in matching OCT scans to their corresponding histological diagnoses, through a 5 × 5 stratified cross-validation process. RESULTS Twenty-four three-dimensional scans (corresponding to approx. 85,603 individual) from ten patients were included in the analysis. In 5 × 5 cross-validation, the model achieved a mean F1-score, sensitivity, and specificity of 0.94, 0.94, and 0.93, respectively. CONCLUSION Optical coherence tomography combined with CNN can differentiate iCCA from liver parenchyma ex vivo. Further studies are necessary to expand on these results and lead to innovative in vivo OCT applications, such as intraoperative or endoscopic scanning.
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Affiliation(s)
- Laura I Wolff
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Enno Hachgenei
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Paul Goßmann
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Mariia Druzenko
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Maik Frye
- Department of Production Quality, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Niels König
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Robert H Schmitt
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
- Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, Aachen, Germany
| | - Alexandros Chrysos
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Katharina Jöchle
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Daniel Truhn
- Department of Diagnostic and Interventional Radiology, University Hospital RWTH Aachen, Aachen, Germany
| | - Jakob Nikolas Kather
- Department of Internal Medicine III, University Hospital RWTH Aachen, Aachen, Germany
- Else Kroener Fresenius Center for Digital Health, Medical Faculty Carl Gustav, Carus Technical University Dresden, Dresden, Germany
| | - Andreas Lambertz
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Nadine T Gaisa
- Institute for Pathology, University Hospital RWTH Aachen, Aachen, Germany
| | - Danny Jonigk
- Institute for Pathology, University Hospital RWTH Aachen, Aachen, Germany
- German Center of Lungs Research (DZL, BREATH), Gießen, Germany
| | - Tom F Ulmer
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Ulf P Neumann
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Sven A Lang
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Iakovos Amygdalos
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Aachen, Germany.
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Amygdalos I, Hachgenei E, Burkl L, Vargas D, Goßmann P, Wolff LI, Druzenko M, Frye M, König N, Schmitt RH, Chrysos A, Jöchle K, Ulmer TF, Lambertz A, Knüchel-Clarke R, Neumann UP, Lang SA. Optical coherence tomography and convolutional neural networks can differentiate colorectal liver metastases from liver parenchyma ex vivo. J Cancer Res Clin Oncol 2022:10.1007/s00432-022-04263-z. [PMID: 35960377 DOI: 10.1007/s00432-022-04263-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/02/2022] [Indexed: 12/24/2022]
Abstract
PURPOSE Optical coherence tomography (OCT) is an imaging technology based on low-coherence interferometry, which provides non-invasive, high-resolution cross-sectional images of biological tissues. A potential clinical application is the intraoperative examination of resection margins, as a real-time adjunct to histological examination. In this ex vivo study, we investigated the ability of OCT to differentiate colorectal liver metastases (CRLM) from healthy liver parenchyma, when combined with convolutional neural networks (CNN). METHODS Between June and August 2020, consecutive adult patients undergoing elective liver resections for CRLM were included in this study. Fresh resection specimens were scanned ex vivo, before fixation in formalin, using a table-top OCT device at 1310 nm wavelength. Scanned areas were marked and histologically examined. A pre-trained CNN (Xception) was used to match OCT scans to their corresponding histological diagnoses. To validate the results, a stratified k-fold cross-validation (CV) was carried out. RESULTS A total of 26 scans (containing approx. 26,500 images in total) were obtained from 15 patients. Of these, 13 were of normal liver parenchyma and 13 of CRLM. The CNN distinguished CRLM from healthy liver parenchyma with an F1-score of 0.93 (0.03), and a sensitivity and specificity of 0.94 (0.04) and 0.93 (0.04), respectively. CONCLUSION Optical coherence tomography combined with CNN can distinguish between healthy liver and CRLM with great accuracy ex vivo. Further studies are needed to improve upon these results and develop in vivo diagnostic technologies, such as intraoperative scanning of resection margins.
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Affiliation(s)
- Iakovos Amygdalos
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Enno Hachgenei
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Luisa Burkl
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - David Vargas
- Institute for Histopathology, University Hospital RWTH Aachen, Aachen, Germany
| | - Paul Goßmann
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Laura I Wolff
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Mariia Druzenko
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Maik Frye
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Niels König
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany
| | - Robert H Schmitt
- Department of Production Metrology, Fraunhofer Institute for Production Technology IPT, Aachen, Germany.,Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, Aachen, Germany
| | - Alexandros Chrysos
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Katharina Jöchle
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Tom F Ulmer
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Andreas Lambertz
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Ruth Knüchel-Clarke
- Institute for Histopathology, University Hospital RWTH Aachen, Aachen, Germany
| | - Ulf P Neumann
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Sven A Lang
- Department of General, Visceral and Transplantation Surgery, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
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Maciel MJ, Pereira HM, Pimenta S, Miranda A, Nunes-Pereira EJ, Correia JH. Differentiation between normal and tumor mammary glands with depth-resolved attenuation coefficient from optical coherence tomography. Biomed Phys Eng Express 2021; 8. [PMID: 34753120 DOI: 10.1088/2057-1976/ac37ca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/09/2021] [Indexed: 11/11/2022]
Abstract
Optical coherence tomography (OCT) is a well-established imaging technology for high-resolution, cross-sectional imaging of biological tissues. Imaging processing and light attenuation coefficient estimation allows to further improve the OCT diagnostic capability. In this paper we use a commercial OCT system, Telesto II-1325LR from Thorlabs, and demonstrate its ability to differentiate normal and tumor mammary mouse glands with the OCT attenuation coefficient. Using several OCT images of normal and tumor mammary mouse glands (n = 26), a statistical analysis was performed. The attenuation coefficient was calculated in depth, considering a slope of 0.5 mm. The normal glands present a median attenuation coefficient of 0.403 mm-1, comparatively to 0.561 mm-1obtained for tumor mammary glands. This translates in an attenuation coefficient approximately 39% higher for tumor mammary glands when compared to normal mammary glands. The OCT attenuation coefficient estimation eliminates the subjective analysis provided by direct visualization of the OCT images.
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Affiliation(s)
| | | | - Sara Pimenta
- CMEMS-UMinho, University of Minho, Guimarães, Portugal
| | - Alice Miranda
- ICVS, School of Medicine, University of Minho, ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Eduardo J Nunes-Pereira
- Centre of Physics of Minho and Porto Universities (CF-UM-UP), University of Minho, Braga, Portugal
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Li Y, Song J, Xia H, Liu G. The experimental study of mouse liver in magneto-acousto-electrical tomography by scan mode. ACTA ACUST UNITED AC 2020; 65:215024. [DOI: 10.1088/1361-6560/abb4bb] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tabish TA, Dey P, Mosca S, Salimi M, Palombo F, Matousek P, Stone N. Smart Gold Nanostructures for Light Mediated Cancer Theranostics: Combining Optical Diagnostics with Photothermal Therapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1903441. [PMID: 32775148 PMCID: PMC7404179 DOI: 10.1002/advs.201903441] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/24/2020] [Indexed: 05/13/2023]
Abstract
Nanotheranostics, which combines optical multiplexed disease detection with therapeutic monitoring in a single modality, has the potential to propel the field of nanomedicine toward genuine personalized medicine. Currently employed mainstream modalities using gold nanoparticles (AuNPs) in diagnosis and treatment are limited by a lack of specificity and potential issues associated with systemic toxicity. Light-mediated nanotheranostics offers a relatively non-invasive alternative for cancer diagnosis and treatment by using AuNPs of specific shapes and sizes that absorb near infrared (NIR) light, inducing plasmon resonance for enhanced tumor detection and generating localized heat for tumor ablation. Over the last decade, significant progress has been made in the field of nanotheranostics, however the main biological and translational barriers to nanotheranostics leading to a new paradigm in anti-cancer nanomedicine stem from the molecular complexities of cancer and an incomplete mechanistic understanding of utilization of Au-NPs in living systems. This work provides a comprehensive overview on the biological, physical and translational barriers facing the development of nanotheranostics. It will also summarise the recent advances in engineering specific AuNPs, their unique characteristics and, importantly, tunability to achieve the desired optical/photothermal properties.
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Affiliation(s)
| | - Priyanka Dey
- School of Physics and AstronomyUniversity of ExeterExeterEX4 4QLUK
| | - Sara Mosca
- Central Laser FacilitySTFC Rutherford Appleton LaboratoryOxfordOX11 0QXUK
| | - Marzieh Salimi
- School of Physics and AstronomyUniversity of ExeterExeterEX4 4QLUK
| | | | - Pavel Matousek
- Central Laser FacilitySTFC Rutherford Appleton LaboratoryOxfordOX11 0QXUK
| | - Nicholas Stone
- School of Physics and AstronomyUniversity of ExeterExeterEX4 4QLUK
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7
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Assessment of tomato soluble solids content and pH by spatially-resolved and conventional Vis/NIR spectroscopy. J FOOD ENG 2018. [DOI: 10.1016/j.jfoodeng.2018.05.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Potentials and pitfalls of gold-silica nanoshell as the exogenous contrast agent for optical diagnosis of cancers: a numerical parametric study. Lasers Med Sci 2018; 34:615-628. [PMID: 30350124 DOI: 10.1007/s10103-018-2639-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
Abstract
For nanoshell-assisted optical detection of cancers, gold shell, silica core (gold-silica) nanoshells are engineered to be the exogenous contrast agent. This work has performed systematic numerical parametric study to investigate the nonlinear dependences of the hemisphere diffuse reflectance on gold-silica nanoshells, laser irradiance, and hosting biology tissue. Planar phantom based tissue models have been constructed as platforms for study. The radiant transport equation (RTE) has been applied to mathematically describe the interactions among laser lights, hosting tissues, and hosted nanoshells. The diffuse reflectance signal under various combinations of parametric conditions has been computed and analyzed. Parametric parameters whose effects on the diffuse reflectance signal have been investigated are: (1) optical properties of a nanoshell generic, (2) nanoshell volume fraction, which is an indicator of nanoshell accumulation in the target tissue site, (3) the width of irradiating laser beam, and (4) thickness of the tissue slab. Seven nanoshell generics have been tested as the exogenous contrast agent including the R[50, 10] (radius of silica core is 50 nm and thickness of gold shell is 10 nm), R[55, 25], R[40, 15], R[40, 40], R[104, 23], R[75, 40] and R[154, 24] nanoshells. It has been found the R[55, 25] nanoshell works best as the exogenous contrast agent, the R[75, 40] and R[104, 23] nanoshells show good potentials as well while the R[50, 10] and R[40, 15] nanoshells should be avoided for diagnostic usage. The practice of neglecting the absorption characteristic of the exogenous contrast agent, which is quite common among the bio-nano community, has been proven to end up with an over-prediction of the effectiveness of the exogenous contrast agent. Such practice therefore is not well justified and should be avoided in future research. Interactions among laser lights, the tissue and nanoshells are highly nonlinear, demonstrated by that nanoshell generics with totally different optical properties might have similar effects on the diffuse reflectance signal and vice versa. Prior to any bench experiment, preliminary numerical investigation as this work has showcased is highly recommended.
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Stohanzlova P, Kolar R. Tissue perfusion modelling in optical coherence tomography. Biomed Eng Online 2017; 16:27. [PMID: 28178998 PMCID: PMC5299764 DOI: 10.1186/s12938-017-0320-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/31/2017] [Indexed: 11/30/2022] Open
Abstract
Background Optical coherence tomography (OCT) is a well established imaging technique with different applications in preclinical research and clinical practice. The main potential for its application lies in the possibility of noninvasively performing “optical biopsy”. Nevertheless, functional OCT imaging is also developing, in which perfusion imaging is an important approach in tissue function study. In spite of its great potential in preclinical research, advanced perfusion imaging using OCT has not been studied. Perfusion analysis is based on administration of a contrast agent (nanoparticles in the case of OCT) into the bloodstream, where during time it specifically changes the image contrast. Through analysing the concentration-intensity curves we are then able to find out further information about the examined tissue. Methods We have designed and manufactured a tissue mimicking phantom that provides the possibility of measuring dilution curves in OCT sequence with flow rates 200, 500, 1000 and 2000 μL/min. The methodology comprised of using bolus of 50 μL of gold nanorods as a contrast agent (with flow rate 5000 μL/min) and continuous imaging by an OCT system. After data acquisition, dilution curves were extracted from OCT intensity images and were subjected to a deconvolution method using an input–output system description. The aim of this was to obtain impulse response characteristics for our model phantom within the tissue mimicking environment. Four mathematical tissue models were used and compared: exponential, gamma, lagged and LDRW. Results We have shown that every model has a linearly dependent parameter on flow (\documentclass[12pt]{minimal}
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\begin{document}$$R^2$$\end{document}R2 values from 0.4914 to 0.9996). We have also shown that using different models can lead to a better understanding of the examined model or tissue. The lagged model surpassed other models in terms of the minimisation criterion and \documentclass[12pt]{minimal}
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\begin{document}$$R^2$$\end{document}R2 value. Conclusions We used a tissue mimicking phantom in our study and showed that OCT can be used for advanced perfusion analysis using mathematical model and deconvolution approach. The lagged model with three parameters is the most appropriate model. Nevertheless, further research have to be performed, particularly with real tissue. Electronic supplementary material The online version of this article (doi:10.1186/s12938-017-0320-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Petra Stohanzlova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 61600, Brno, Czech Republic.
| | - Radim Kolar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 61600, Brno, Czech Republic
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Oldenburg AL, Blackmon RL, Sierchio JM. Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2016; 22:6803913. [PMID: 27429543 PMCID: PMC4941814 DOI: 10.1109/jstqe.2016.2553084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Optical coherence tomography (OCT) has gained widespread application for many biomedical applications, yet the traditional array of contrast agents used in incoherent imaging modalities do not provide contrast in OCT. Owing to the high biocompatibility of iron oxides and noble metals, magnetic and plasmonic nanoparticles, respectively, have been developed as OCT contrast agents to enable a range of biological and pre-clinical studies. Here we provide a review of these developments within the past decade, including an overview of the physical contrast mechanisms and classes of OCT system hardware addons needed for magnetic and plasmonic nanoparticle contrast. A comparison of the wide variety of nanoparticle systems is also presented, where the figures of merit depend strongly upon the choice of biological application.
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Affiliation(s)
- Amy L. Oldenburg
- Department of Physics and Astronomy, the Department of Biomedical Engineering, and the Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 USA
| | - Richard L. Blackmon
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 USA
| | - Justin M. Sierchio
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 USA
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Nader CA, Nassif R, Pellen F, Le Jeune B, Le Brun G, Abboud M. Influence of size, proportion, and absorption coefficient of spherical scatterers on the degree of light polarization and the grain size of speckle pattern. APPLIED OPTICS 2015; 54:10369-10375. [PMID: 26836860 DOI: 10.1364/ao.54.010369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper, we present the evolution of speckle pattern polarimetric parameters in response to controlled changes in scatterer sizes, proportions, and the absorption coefficient in media. The experimental study was performed on mixtures of polystyrene microspheres with dye in order to ensure biological medium-like properties. The speckle grain sizes and degrees of polarization for linear and circular light were monitored. We observed helicity flipping in the degree of circular polarization for small scatterer proportion around 25%. Furthermore, linear depolarization decreased slightly for media containing more small particles. Good agreement was shown with numerical results computed using a Monte Carlo simulation of polarized light taking into account our experimental configuration. Speckle grain size also evolves with the increase of small scatterers as well as the media absorption coefficient. Such variations of properties are encountered during fruit maturation, in tissues in precancerous stages, and any transformation that causes a modification in particle proportions and absorption coefficient in biological media. The computed parameters proved to be sensitive to these changes.
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