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Zhao X, Liu W, Hu Z, Duan L, Zhang X, Li F, Hong B. Rapid prototyping of a retinal multivascular network phantom for optical retinal vascular imaging equipment evaluation. BIOMEDICAL OPTICS EXPRESS 2024; 15:4253-4263. [PMID: 39022546 PMCID: PMC11249693 DOI: 10.1364/boe.523115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/12/2024] [Accepted: 05/30/2024] [Indexed: 07/20/2024]
Abstract
Retinal vascular health holds paramount importance for healthy vision. Many technologies have been developed to examine retinal vasculature non-destructively, including fundus cameras, optical coherence tomography angiography (OCTA), fluorescein angiography (FA), and so on. However, there is a lack of a proper phantom simulating the critical features of the real human retina to calibrate and evaluate the performance of these technologies. In this work, we present a rapid, high-resolution, and economical technology based on 3D printed mold-based soft lithography and spin coating for the fabrication of a multivascular network and multilayer structural retinal phantom with the appropriate optical properties. The feasibility of the retinal phantom as a test device was demonstrated with an OCTA system and a confocal retinal ophthalmoscope. Experiment results prove that the retinal phantom could provide an objective evaluation of the OCTA and confocal retinal ophthalmoscope. Furthermore, the microfluidic phantoms enabled by this fabrication technology may support the development and evaluation of other techniques.
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Affiliation(s)
- Xiaowei Zhao
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
| | - Wenli Liu
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
| | - Zhixiong Hu
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
| | - Liangcheng Duan
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
| | - Xiao Zhang
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Fei Li
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
| | - Baoyu Hong
- Center for Medical Metrology, National Institute of Metrology, 18 North 3rd Ring East Rd., Chaoyang, Beijing 100029, China
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Tran MH, Fei B. Compact and ultracompact spectral imagers: technology and applications in biomedical imaging. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:040901. [PMID: 37035031 PMCID: PMC10075274 DOI: 10.1117/1.jbo.28.4.040901] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 02/27/2023] [Indexed: 05/18/2023]
Abstract
Significance Spectral imaging, which includes hyperspectral and multispectral imaging, can provide images in numerous wavelength bands within and beyond the visible light spectrum. Emerging technologies that enable compact, portable spectral imaging cameras can facilitate new applications in biomedical imaging. Aim With this review paper, researchers will (1) understand the technological trends of upcoming spectral cameras, (2) understand new specific applications that portable spectral imaging unlocked, and (3) evaluate proper spectral imaging systems for their specific applications. Approach We performed a comprehensive literature review in three databases (Scopus, PubMed, and Web of Science). We included only fully realized systems with definable dimensions. To best accommodate many different definitions of "compact," we included a table of dimensions and weights for systems that met our definition. Results There is a wide variety of contributions from industry, academic, and hobbyist spaces. A variety of new engineering approaches, such as Fabry-Perot interferometers, spectrally resolved detector array (mosaic array), microelectro-mechanical systems, 3D printing, light-emitting diodes, and smartphones, were used in the construction of compact spectral imaging cameras. In bioimaging applications, these compact devices were used for in vivo and ex vivo diagnosis and surgical settings. Conclusions Compact and ultracompact spectral imagers are the future of spectral imaging systems. Researchers in the bioimaging fields are building systems that are low-cost, fast in acquisition time, and mobile enough to be handheld.
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Affiliation(s)
- Minh H. Tran
- University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, United States
| | - Baowei Fei
- University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, United States
- University of Texas Southwestern Medical Center, Department of Radiology, Dallas, Texas, United States
- University of Texas at Dallas, Center for Imaging and Surgical Innovation, Richardson, Texas, United States
- Address all correspondence to Baowei Fei,
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Schädel-Ebner S, Hirsch O, Gladytz T, Gutkelch D, Licha K, Berger J, Grosenick D. 3D-printed tissue-simulating phantoms for near-infrared fluorescence imaging of rheumatoid diseases. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:074702. [PMID: 35711096 PMCID: PMC9201974 DOI: 10.1117/1.jbo.27.7.074702] [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: 08/26/2021] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Fluorescence imaging of rheumatoid diseases with indocyanine green (ICG) is an emerging technique with unique potential for diagnosis and therapy. Device characterization, monitoring of the performance, and further developments of the technique require tissue-equivalent fluorescent phantoms of high stability with appropriate anatomical shapes. AIM Our investigations aim at the development of a three-dimensional (3D) printing technique to fabricate hand and finger models with appropriate optical properties in the near-infrared spectral range. These phantoms should have fluorescence properties similar to ICG, and excellent photostability and durability over years. APPROACH We modified a 3D printing methacrylate photopolymer by adding the fluorescent dye Lumogen IR 765 to the raw material. Reduced scattering and absorption coefficients were adjusted to values representative of the human hand by incorporating titanium dioxide powder and black ink. The properties of printed phantoms of various compositions were characterized using UV/Vis and fluorescence spectroscopy, and time-resolved measurements. Photostability and bleaching were investigated with a hand imager. For comparison, several phantoms with ICG as fluorescent dye were printed and characterized as well. RESULTS The spectral properties of Lumogen IR 765 are very similar to those of ICG. By optimizing the concentrations of Lumogen, titanium dioxide, and ink, anatomically shaped hand and vessel models with properties equivalent to in vivo investigations with a fluorescence hand imager could be printed. Phantoms with Lumogen IR 765 had an excellent photostability over up to 4 years. In contrast, phantoms printed with ICG showed significant bleaching and degradation of fluorescence over time. CONCLUSIONS 3D printing of phantoms with Lumogen IR 765 is a promising method for fabricating anatomically shaped fluorescent tissue models of excellent stability with spectral properties similar to ICG. The phantoms are well-suited to monitor the performance of hand imagers. Concepts can easily be transferred to other fluorescence imaging applications of ICG.
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Affiliation(s)
| | - Ole Hirsch
- Hochschule für angewandte Wissenschaft und Kunst Hildesheim/Holzminden/Göttingen (HAWK), Fakultät Ingenieurwissenschaften und Gesundheit, Göttingen, Germany
| | - Thomas Gladytz
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft (MDC), Berlin, Germany
| | - Dirk Gutkelch
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Kai Licha
- FEW Chemicals GmbH, Bitterfeld-Wolfen, Germany
| | | | - Dirk Grosenick
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
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4
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Akitegetse C, Landry P, Robidoux J, Lapointe N, Brouard D, Sauvageau D. Monte-Carlo simulation and tissue-phantom model for validation of ocular oximetry. BIOMEDICAL OPTICS EXPRESS 2022; 13:2929-2946. [PMID: 35774309 PMCID: PMC9203094 DOI: 10.1364/boe.458079] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/27/2022] [Accepted: 04/11/2022] [Indexed: 06/15/2023]
Abstract
Ocular oximetry, in which blood oxygen saturation is evaluated in retinal tissues, is a promising technique for the prevention, diagnosis and management of many diseases and conditions. However, the development of new tools for evaluating oxygen saturation in the eye fundus has often been limited by the lack of reference tools or techniques for such measurements. In this study, we describe a two-step validation method. The impact of scattering, blood volume fraction and lens yellowing on the oximetry model is investigated using a tissue phantom, while a Monte Carlo model of the light propagation in the eye fundus is used to study the effect of the fundus layered-structure. With this method, we were able to assess the performance of an ocular oximetry technique in the presence of confounding factors and to quantify the impact of the choroidal circulation on the accuracy of the measurements. The presented strategy will be useful to anyone involved in studies based on the eye fundus diffuse reflectance.
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Affiliation(s)
| | - Patricia Landry
- Affaires médicales et innovation, Héma-Québec, Québec, QC, G1V 5C3, Canada
| | - Jonathan Robidoux
- Affaires médicales et innovation, Héma-Québec, Québec, QC, G1V 5C3, Canada
| | | | - Danny Brouard
- Affaires médicales et innovation, Héma-Québec, Québec, QC, G1V 5C3, Canada
| | - Dominic Sauvageau
- Zilia inc., Québec, QC, G1K 3G5, Canada
- Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
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Hacker L, Wabnitz H, Pifferi A, Pfefer TJ, Pogue BW, Bohndiek SE. Criteria for the design of tissue-mimicking phantoms for the standardization of biophotonic instrumentation. Nat Biomed Eng 2022; 6:541-558. [PMID: 35624150 DOI: 10.1038/s41551-022-00890-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 02/07/2022] [Indexed: 01/08/2023]
Abstract
A lack of accepted standards and standardized phantoms suitable for the technical validation of biophotonic instrumentation hinders the reliability and reproducibility of its experimental outputs. In this Perspective, we discuss general criteria for the design of tissue-mimicking biophotonic phantoms, and use these criteria and state-of-the-art developments to critically review the literature on phantom materials and on the fabrication of phantoms. By focusing on representative examples of standardization in diffuse optical imaging and spectroscopy, fluorescence-guided surgery and photoacoustic imaging, we identify unmet needs in the development of phantoms and a set of criteria (leveraging characterization, collaboration, communication and commitment) for the standardization of biophotonic instrumentation.
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Affiliation(s)
- Lina Hacker
- Department of Physics, University of Cambridge, Cambridge, UK.,Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | | | | | - Brian W Pogue
- Thayer School of Engineering, Dartmouth, Hanover, NH, USA
| | - Sarah E Bohndiek
- Department of Physics, University of Cambridge, Cambridge, UK. .,Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
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6
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Hariri A, Palma-Chavez J, Wear KA, Pfefer TJ, Jokerst JV, Vogt WC. Polyacrylamide hydrogel phantoms for performance evaluation of multispectral photoacoustic imaging systems. PHOTOACOUSTICS 2021; 22:100245. [PMID: 33747787 PMCID: PMC7972966 DOI: 10.1016/j.pacs.2021.100245] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/09/2020] [Accepted: 02/12/2021] [Indexed: 05/21/2023]
Abstract
As photoacoustic imaging (PAI) begins to mature and undergo clinical translation, there is a need for well-validated, standardized performance test methods to support device development, quality control, and regulatory evaluation. Despite recent progress, current PAI phantoms may not adequately replicate tissue light and sound transport over the full range of optical wavelengths and acoustic frequencies employed by reported PAI devices. Here we introduce polyacrylamide (PAA) hydrogel as a candidate material for fabricating stable phantoms with well-characterized optical and acoustic properties that are biologically relevant over a broad range of system design parameters. We evaluated suitability of PAA phantoms for conducting image quality assessment of three PAI systems with substantially different operating parameters including two commercial systems and a custom system. Imaging results indicated that appropriately tuned PAA phantoms are useful tools for assessing and comparing PAI system image quality. These phantoms may also facilitate future standardization of performance test methodology.
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Affiliation(s)
- Ali Hariri
- Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Jorge Palma-Chavez
- Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Keith A Wear
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Jesse V Jokerst
- Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
- Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA 92093, USA
| | - William C Vogt
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
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Fales AM, Strobbia P, Vo-Dinh T, Ilev IK, Pfefer TJ. 3D-printed phantoms for characterizing SERS nanoparticle detectability in turbid media. Analyst 2021; 145:6045-6053. [PMID: 32766656 DOI: 10.1039/d0an01295e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent advances in plasmonic nanoparticle synthesis have enabled extremely high per-particle surface-enhanced Raman scattering (SERS) efficiencies. This has led to the development of SERS tags for in vivo applications (e.g. tumor targeting and detection), providing high sensitivity and fingerprint-like molecular specificity. While the SERS enhancement factor is a major contributor to SERS tag performance, in practice the throughput and excitation-collection geometry of the optical system can significantly impact detectability. Test methods to objectively quantify SERS particle performance under realistic conditions are necessary to facilitate clinical translation. Towards this goal, we have developed 3D-printed phantoms with tunable, biologically-relevant optical properties. Phantoms were designed to include 1 mm-diameter channels at different depths, which can be filled with SERS tag solutions. The effects of channel depth and particle concentration on the detectability of three different SERS tags were evaluated using 785 nm laser excitation at the maximum permissible exposure for skin. Two of these tags were commercially available, featuring gold nanorods as the SERS particle, while the third tag was prepared in-house using silver-coated gold nanostars. Our findings revealed that the measured SERS intensity of tags in solution is not always a reliable predictor of detectability when applied in a turbid medium such as tissue. The phantoms developed in this work can be used to assess the suitability of specific SERS tags and instruments for their intended clinical applications and provide a means of optimizing new SERS device-tag combination products.
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Affiliation(s)
- Andrew M Fales
- Division of Biomedical Physics, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, USA.
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Horng H, O'Brien K, Lamont A, Sochol RD, Pfefer TJ, Chen Y. 3D printed vascular phantoms for high-resolution biophotonic image quality assessment via direct laser writing. OPTICS LETTERS 2021; 46:1987-1990. [PMID: 33857123 DOI: 10.1364/ol.412849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/13/2021] [Indexed: 06/12/2023]
Abstract
Fluorescence imaging techniques such as fluorescein angiography and fundus autofluorescence are often used to diagnose retinal pathologies; however, there are currently no standardized test methods for evaluating device performance. Here we present microstructured fluorescent phantoms fabricated using a submicron-scale three-dimensional printing technology, direct laser writing (DLW). We employ an in situ DLW technique to print 10 µm diameter microfluidic channels that support perfusions of fluorescent dyes. We then demonstrate how broadband photoresist fluorescence can be exploited to generate resolution targets and biomimetic models of retinal vasculature using standard DLW processes. The results indicate that these approaches show significant promise for generating better performance evaluation tools for fluorescence microscopy and imaging devices.
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Clancy NT, Jones G, Maier-Hein L, Elson DS, Stoyanov D. Surgical spectral imaging. Med Image Anal 2020; 63:101699. [PMID: 32375102 PMCID: PMC7903143 DOI: 10.1016/j.media.2020.101699] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 03/30/2020] [Accepted: 04/06/2020] [Indexed: 12/24/2022]
Abstract
Recent technological developments have resulted in the availability of miniaturised spectral imaging sensors capable of operating in the multi- (MSI) and hyperspectral imaging (HSI) regimes. Simultaneous advances in image-processing techniques and artificial intelligence (AI), especially in machine learning and deep learning, have made these data-rich modalities highly attractive as a means of extracting biological information non-destructively. Surgery in particular is poised to benefit from this, as spectrally-resolved tissue optical properties can offer enhanced contrast as well as diagnostic and guidance information during interventions. This is particularly relevant for procedures where inherent contrast is low under standard white light visualisation. This review summarises recent work in surgical spectral imaging (SSI) techniques, taken from Pubmed, Google Scholar and arXiv searches spanning the period 2013-2019. New hardware, optimised for use in both open and minimally-invasive surgery (MIS), is described, and recent commercial activity is summarised. Computational approaches to extract spectral information from conventional colour images are reviewed, as tip-mounted cameras become more commonplace in MIS. Model-based and machine learning methods of data analysis are discussed in addition to simulation, phantom and clinical validation experiments. A wide variety of surgical pilot studies are reported but it is apparent that further work is needed to quantify the clinical value of MSI/HSI. The current trend toward data-driven analysis emphasises the importance of widely-available, standardised spectral imaging datasets, which will aid understanding of variability across organs and patients, and drive clinical translation.
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Affiliation(s)
- Neil T Clancy
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), University College London, United Kingdom; Centre for Medical Image Computing (CMIC), Department of Medical Physics and Biomedical Engineering, University College London, United Kingdom.
| | - Geoffrey Jones
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), University College London, United Kingdom; Centre for Medical Image Computing (CMIC), Department of Computer Science, University College London, United Kingdom
| | | | - Daniel S Elson
- Hamlyn Centre for Robotic Surgery, Institute of Global Health Innovation, Imperial College London, United Kingdom; Department of Surgery and Cancer, Imperial College London, United Kingdom
| | - Danail Stoyanov
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences (WEISS), University College London, United Kingdom; Centre for Medical Image Computing (CMIC), Department of Computer Science, University College London, United Kingdom
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Naglič P, Zelinskyi Y, Rogelj L, Stergar J, Milanič M, Novak J, Kumperščak B, Bürmen M. Optical properties of PlatSil SiliGlass tissue-mimicking phantoms. BIOMEDICAL OPTICS EXPRESS 2020; 11:3753-3768. [PMID: 33014564 PMCID: PMC7510920 DOI: 10.1364/boe.391720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/08/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
In this work, we revise the preparation procedure and conduct an in depth characterization of optical properties for the recently proposed silicone-based tissue-mimicking optical phantoms in the spectral range from 475 to 925 nm. The optical properties are characterized in terms of refractive index and its temperature dependence, absorption and reduced scattering coefficients and scattering phase function related quantifiers. The scattering phase function and related quantifiers of the optical phantoms are first assessed within the framework of the Mie theory by using the measured refractive index of SiliGlass and size distribution of the hollow silica spherical particles that serve as scatterers. A set of purely absorbing optical phantoms in cuvettes is used to evaluate the linearity of the absorption coefficient with respect to the concentration of black pigment that serves as the absorber. Finally, the optical properties in terms of the absorption and reduced scattering coefficients and the subdiffusive scattering phase function quantifier γ are estimated for a subset of phantoms from spatially resolved reflectance using deep learning aided inverse models. To this end, an optical fiber probe with six linearly arranged optical fibers is used to collect the backscattered light at small and large distances from the source fiber. The underlying light propagation modeling is based on the stochastic Monte Carlo method that accounts for all the details of the optical fiber probe.
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Affiliation(s)
- Peter Naglič
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Yevhen Zelinskyi
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Luka Rogelj
- University of Ljubljana, Faculty of Mathematics and Physics, Jadranska ulica 19, 1000 Ljubljana, Slovenia
| | - Jošt Stergar
- University of Ljubljana, Faculty of Mathematics and Physics, Jadranska ulica 19, 1000 Ljubljana, Slovenia
| | - Matija Milanič
- University of Ljubljana, Faculty of Mathematics and Physics, Jadranska ulica 19, 1000 Ljubljana, Slovenia
- Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Jure Novak
- Dia-Vit d.o.o., Litijska cesta 186e, 1000 Ljubljana, Slovenia
| | | | - Miran Bürmen
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
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Kanniyappan U, Wang B, Yang C, Ghassemi P, Litorja M, Suresh N, Wang Q, Chen Y, Pfefer TJ. Performance test methods for near-infrared fluorescence imaging. Med Phys 2020; 47:3389-3401. [PMID: 32304583 PMCID: PMC7496362 DOI: 10.1002/mp.14189] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/03/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Near-infrared fluorescence (NIRF) imaging using exogenous contrast has gained much attention as a technique for enhancing visualization of vasculature using untargeted agents, as well as for the detection and localization of cancer with targeted agents. In order to address the emerging need for standardization of NIRF imaging technologies, it is necessary to identify the best practices suitable for objective, quantitative testing of key image quality characteristics. Toward the development of a battery of test methods that are rigorous yet applicable to a wide variety of devices, we have evaluated techniques for phantom design, measurement, and calculation of specific performance metrics. METHODS Using a NIRF imaging system for indocyanine green imaging, providing excitation at 780 nm and detection above 830 nm, we explored methods to evaluate uniformity, field of view, spectral crosstalk, spatial resolution, depth of field, sensitivity, linearity, and penetration depth. These measurements were performed using fluorophore-doped multiwell plate and high turbidity planar phantoms, as well as a 3D-printed multichannel phantom and a USAF 1951 resolution target. RESULTS AND CONCLUSIONS Based on a wide range of approaches described in medical and fluorescence imaging literature, we have developed and demonstrated a cohesive battery of test methods for evaluation of fluorescence image quality in wide-field imagers. We also propose a number of key metrics that can facilitate direct, quantitative comparison of device performance. These methods have the potential to facilitate more uniform evaluation and inter-comparison of clinical and preclinical imaging systems than is typically achieved, with the long-term goal of establishing international standards for fluorescence image quality assessment.
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Affiliation(s)
- Udayakumar Kanniyappan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Bohan Wang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Charles Yang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Pejhman Ghassemi
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Maritoni Litorja
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Nitin Suresh
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Quanzeng Wang
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Department of Biomedical Engineering, University of Massachusetts Amherst, MA, USA
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
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Ruiz AJ, Wu M, LaRochelle EPM, Gorpas D, Ntziachristos V, Pfefer TJ, Pogue BW. Indocyanine green matching phantom for fluorescence-guided surgery imaging system characterization and performance assessment. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-15. [PMID: 32441066 PMCID: PMC7240319 DOI: 10.1117/1.jbo.25.5.056003] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 05/11/2020] [Indexed: 05/13/2023]
Abstract
SIGNIFICANCE Expanded use of fluorescence-guided surgery with devices approved for use with indocyanine green (ICG) has led to a range of commercial systems available. There is a compelling need to be able to independently characterize system performance and allow for cross-system comparisons. AIM The goal of this work is to expand on previous proposed fluorescence imaging standard designs to develop a long-term stable phantom that spectrally matches ICG characteristics and utilizes 3D printing technology for incorporating tissue-equivalent materials. APPROACH A batch of test targets was created to assess ICG concentration sensitivity in the 0.3- to 1000-nM range, tissue-equivalent depth sensitivity down to 6 mm, and spatial resolution with a USAF test chart. Comparisons were completed with a range of systems that have significantly different imaging capabilities and applications, including the Li-Cor® Odyssey, Li-Cor® Pearl, PerkinElmer® Solaris, and Stryker® Spy Elite. RESULTS Imaging of the ICG-matching phantoms with all four commercially available systems showed the ability to benchmark system performance and allow for cross-system comparisons. The fluorescence tests were able to assess differences in the detectable concentrations of ICG with sensitivity differences >10× for preclinical and clinical systems. Furthermore, the tests successfully assessed system differences in the depth-signal decay rate, as well as resolution performance and image artifacts. The manufacturing variations, photostability, and mechanical design of the tests showed promise in providing long-term stable standards for fluorescence imaging. CONCLUSIONS The presented ICG-matching phantom provides a major step toward standardizing performance characterization and cross-system comparisons for devices approved for use with ICG. The developed hybrid manufacturing platform can incorporate long-term stable fluorescing agents with 3D printed tissue-equivalent material. Further, long-term testing of the phantom and refinements to the manufacturing process are necessary for future implementation as a widely adopted fluorescence imaging standard.
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Affiliation(s)
- Alberto J. Ruiz
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Address all correspondence to Alberto J. Ruiz, E-mail: ; Brian W. Pogue, E-mail:
| | - Mindy Wu
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | | | - Dimitris Gorpas
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Munich, Germany
- Technical University Munich, Helmholtz Zentrum Munich, Munich, Germany
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Munich, Germany
- Technical University Munich, Helmholtz Zentrum Munich, Munich, Germany
| | - T. Joshua Pfefer
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Rockville, Maryland, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Geisel School of Medicine, Department of Surgery, Hanover, New Hampshire, United States
- Address all correspondence to Alberto J. Ruiz, E-mail: ; Brian W. Pogue, E-mail:
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Afshari A, Ghassemi P, Lin J, Halprin M, Wang J, Mendoza G, Weininger S, Pfefer TJ. Cerebral oximetry performance testing with a 3D-printed vascular array phantom. BIOMEDICAL OPTICS EXPRESS 2019; 10:3731-3746. [PMID: 31452971 PMCID: PMC6701524 DOI: 10.1364/boe.10.003731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 05/13/2023]
Abstract
Cerebral oximetry based on near-infrared spectroscopy represents a unique noninvasive tool for real-time surgical monitoring, yet studies have shown a significant discrepancy in accuracy among commercial systems. Towards the establishment of a standardized method for performance testing, we have studied a solid phantom approach - based on a 3D-printed cerebrovascular module (CVM) incorporating an array of 148 cylindrical channels - that has several advantages over liquid phantoms. Development and characterization of a CVM prototype are described, including high-resolution imaging and spectrophotometry measurements. The CVM was filled with whole bovine blood tuned over an oxygen saturation range of 30-90% and molded-silicone layers simulating extracerebral tissues were used to evaluate penetration depth. Saturation measurement accuracy was assessed in two commercially-available clinical cerebral oximeters. For one oximeter, both neonatal and pediatric sensors showed a high degree of precision, whereas accuracy was strongly dependent on saturation level and extracerebral geometry. The second oximeter showed worse precision, yet greater robustness to variations in extracerebral layers. These results indicate that 3D-printed channel array phantoms represent a promising new approach for standardized testing of clinical oximeters.
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14
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Hornberger C, Wabnitz H. Approaches for calibration and validation of near-infrared optical methods for oxygenation monitoring. ACTA ACUST UNITED AC 2019; 63:537-546. [PMID: 29425103 DOI: 10.1515/bmt-2017-0116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/10/2017] [Indexed: 11/15/2022]
Abstract
Pulse oximetry for arterial oxygenation monitoring and tissue oximetry for monitoring of cerebral oxygenation or muscle oxygenation are based on quantitative in vivo diffuse optical spectroscopy. However, in both cases the information on absolute or relative concentration of human tissue constituents and especially on hemoglobin oxygenation can often not be retrieved by model-based analysis. An in vivo calibration against an accepted reference measurement can be a practical alternative. Pulse oximeters and most of commercial cerebral tissue oximeters rely on empirical calibration based on invasive controlled human desaturation studies. As invasive in vivo tests on healthy subjects are ethically disputable and should be limited to exceptional cases this calibration practice is unsatisfactory. We present the current status and problems of calibration and validation in pulse oximetry and cerebral tissue oximetry including the pros and cons of in vivo as well as in vitro methods. We emphasize various digital and physical phantom approaches and discuss the prospects of their application and possible further developments.
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Affiliation(s)
- Christoph Hornberger
- Faculty of Engineering, Wismar University of Applied Sciences, 23966 Wismar, Germany
| | - Heidrun Wabnitz
- Physikalisch-Technische Bundesanstalt (PTB), 10587 Berlin, Germany
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15
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Chen H, Liu G, Zhang S, Shen S, Luo Y, Li J, Roberts CJ, Sun M, Xu RX. Fundus-simulating phantom for calibration of retinal vessel oximetry devices. APPLIED OPTICS 2019; 58:3877-3885. [PMID: 31158206 DOI: 10.1364/ao.58.003877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/10/2019] [Indexed: 06/09/2023]
Abstract
Retinal vessel oxygen supply is important for retinal tissue metabolism. Commonly used retinal vessel oximetry devices are based on dual-wavelength spectral measurement of oxyhemoglobin and deoxyhemoglobin. However, there is no traceable standard for reliable calibration of these devices. In this study, we developed a fundus-simulating phantom that closely mimicked the optical properties of human fundus tissues. Microchannels of precisely controlled topological structures were produced by soft lithography to simulate the retinal vasculature. Optical properties of the phantom were adjusted by adding scattering and absorption agents to simulate different concentrations of fundus pigments. The developed phantom was used to calibrate the linear correlation between oxygen saturation (SO2) level and optical density ratio in a dual-wavelength oximetry device. The obtained calibration factors were used to calculate the retinal vessel SO2 in both eyes of five volunteers aged between 24 and 27 years old. The test results showed that the mean arterial and venous SO2 levels after phantom calibration were coincident with those after empirical value calibration, indicating the potential clinical utility of the produced phantom as a calibration standard.
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16
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Kedia N, Liu Z, Sochol RD, Tam J, Hammer DX, Agrawal A. 3-D printed photoreceptor phantoms for evaluating lateral resolution of adaptive optics imaging systems. OPTICS LETTERS 2019; 44:1825-1828. [PMID: 30933157 DOI: 10.1364/ol.44.001825] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
With adaptive optics (AO), optical coherence tomography and scanning laser ophthalmoscopy imaging systems can resolve individual photoreceptor cells in living eyes, due to enhanced lateral spatial resolution. However, no standard test method exists for experimentally quantifying this parameter in ophthalmic AO imagers. Here, we present three-dimensional (3-D) printed phantoms, which enable the measurement of lateral resolution in an anatomically relevant manner. We used two-photon polymerization to fabricate two phantoms, which mimic the mosaic of cone photoreceptor outer segments at multiple retinal eccentricities. With these phantoms, we demonstrated that the resolution of two multimodal AO systems is similar to theoretical predictions, with some intriguing speckle effects.
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17
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Hernandez-Quintanar L, Rodriguez-Salvador M. Discovering new 3D bioprinting applications: Analyzing the case of optical tissue phantoms. Int J Bioprint 2018; 5:178. [PMID: 32596533 PMCID: PMC7294689 DOI: 10.18063/ijb.v5i1.178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 12/18/2018] [Indexed: 11/25/2022] Open
Abstract
Optical tissue phantoms enable to mimic the optical properties of biological tissues for biomedical device calibration, new equipment validation, and clinical training for the detection, and treatment of diseases. Unfortunately, current methods for their development present some problems, such as a lack of repeatability in their optical properties. Where the use of three-dimensional (3D) printing or 3D bioprinting could address these issues. This paper aims to evaluate the use of this technology in the development of optical tissue phantoms. A competitive technology intelligence methodology was applied by analyzing Scopus, Web of Science, and patents from January 1, 2000, to July 31, 2018. The main trends regarding methods, materials, and uses, as well as predominant countries, institutions, and journals, were determined. The results revealed that, while 3D printing is already employed (in total, 108 scientific papers and 18 patent families were identified), 3D bioprinting is not yet applied for optical tissue phantoms. Nevertheless, it is expected to have significant growth. This research gives biomedical scientists a new window of opportunity for exploring the use of 3D bioprinting in a new area that may support testing of new equipment and development of techniques for the diagnosis and treatment of diseases.
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18
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Liu Y, Ghassemi P, Depkon A, Iacono MI, Lin J, Mendoza G, Wang J, Tang Q, Chen Y, Pfefer TJ. Biomimetic 3D-printed neurovascular phantoms for near-infrared fluorescence imaging. BIOMEDICAL OPTICS EXPRESS 2018; 9:2810-2824. [PMID: 30258692 PMCID: PMC6154206 DOI: 10.1364/boe.9.002810] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 05/03/2023]
Abstract
Emerging three-dimensional (3D) printing technology enables the fabrication of optically realistic and morphologically complex tissue-simulating phantoms for the development and evaluation of novel optical imaging products. In this study, we assess the potential to print image-defined neurovascular phantoms with patent channels for contrast-enhanced near-infrared fluorescence (NIRF) imaging. An anatomical map defined from clinical magnetic resonance imaging (MRI) was segmented and processed into files suitable for printing a forebrain vessel network in rectangular and curved-surface biomimetic phantoms. Methods for effectively cleaning samples with complex vasculature were determined. A final set of phantoms were imaged with a custom NIRF system at 785 nm excitation using two NIRF contrast agents. In addition to demonstrating the strong potential of 3D printing for creating highly realistic, patient-specific biophotonic phantoms, our work provides insight into optimal methods for accomplishing this goal and elucidates current limitations of this approach.
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Affiliation(s)
- Yi Liu
- Department of Bioengineering, University of Maryland, Silver Spring, MD, USA
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
- Authors contributed equally to this work
| | - Pejhman Ghassemi
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
- Authors contributed equally to this work
| | - Andrew Depkon
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
- Marquette University, Milwaukee, WI, USA
| | - Maria Ida Iacono
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Jonathan Lin
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Gonzalo Mendoza
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Jianting Wang
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Qinggong Tang
- Department of Bioengineering, University of Maryland, Silver Spring, MD, USA
| | - Yu Chen
- Department of Bioengineering, University of Maryland, Silver Spring, MD, USA
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, USA
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19
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Lv X, Chen H, Liu G, Shen S, Wu Q, Hu C, Li J, Dong E, Xu RX. Design of a portable phantom device to simulate tissue oxygenation and blood perfusion. APPLIED OPTICS 2018; 57:3938-3946. [PMID: 29791363 DOI: 10.1364/ao.57.003938] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
We propose a portable phantom system for calibration and validation of medical optical devices in a clinical setting. The phantom system comprises a perfusion module and an exchangeable tissue-simulating phantom that simulates tissue oxygenation and blood perfusion. The perfusion module consists of a peristaltic pump, two liquid storage units, and two pressure suppressors. The tissue-simulating phantom is fabricated by a three-dimensional (3D) printing process with microchannels embedded to simulate blood vessels. Optical scattering and absorption properties of biologic tissue are simulated by mixing graphite powder and titanium dioxide powder with clear photoreactive resin at specific ratios. Tissue oxygen saturation (StO2) and blood perfusion are simulated by circulating the mixture of blood and intralipid at different oxygenation levels and flow rates. A house-made multimodal imaging system that combines multispectral imaging and laser speckle imaging are used for non-invasive detection of phantom oxygenation and perfusion, and the measurements are compared with those of a commercial Moor device as well as numerical simulation. By acquiring multimodal imaging data from one phantom and applying the calibration factors in different settings, we demonstrate the technical feasibility to calibrate optical devices for consistent measurements. By simulating retina tissue vasculature and acquiring functional images at different tissue oxygenation and blood perfusion levels, we demonstrate the clinical potential to simulate tissue anomalies. Our experiments imply the clinical potential of a portable, low-cost, and traceable phantom standard to calibrate and validate medical optical devices for improved performance.
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Affiliation(s)
- Lewis. E. MacKenzie
- School of Biomedical Sciences, University of Leeds, Garstang Building Leeds, Leeds, UK
| | - Andy. R. Harvey
- School of Physics and Astronomy, Kelvin Building University of Glasgow University Avenue, Glasgow, UK
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21
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van der Putten MA, MacKenzie LE, Davies AL, Fernandez-Ramos J, Desai RA, Smith KJ, Harvey AR. A multispectral microscope for in vivo oximetry of rat dorsal spinal cord vasculature. Physiol Meas 2016; 38:205-218. [PMID: 28001129 DOI: 10.1088/1361-6579/aa5527] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Quantification of blood oxygen saturation (SO2) in vivo is essential for understanding the pathogenesis of diseases in which hypoxia is thought to play a role, including inflammatory disorders such as multiple sclerosis (MS) and rheumatoid arthritis (RA). We describe a low-cost multispectral microscope and oximetry technique for calibration-free absolute oximetry of surgically exposed blood vessels in vivo. We imaged the vasculature of the dorsal spinal cord in healthy rats, and varied inspired oxygen (FiO2) in order to evaluate the sensitivity of the imaging system to changes in SO2. The venous SO2 was calculated as 67.8 ± 10.4% (average ± standard deviation), increasing to 83.1 ± 11.6% under hyperoxic conditions (100% FiO2) and returning to 67.4 ± 10.9% for a second normoxic period; the venous SO2 was 50.9 ± 15.5% and 29.2 ± 24.6% during subsequent hypoxic states (18% and 15% FiO2 respectively). We discuss the design and performance of our multispectral imaging system, and the future scope for extending this oximetry technique to quantification of hypoxia in inflamed tissue.
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22
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Bentz BZ, Bowen AG, Lin D, Ysselstein D, Huston DH, Rochet JC, Webb KJ. Printed optics: phantoms for quantitative deep tissue fluorescence imaging. OPTICS LETTERS 2016; 41:5230-5233. [PMID: 27842100 PMCID: PMC5650700 DOI: 10.1364/ol.41.005230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Three-dimensional (3D) printing allows for complex or physiologically realistic phantoms, useful, for example, in developing biomedical imaging methods and for calibrating measured data. However, available 3D printing materials provide a limited range of static optical properties. We overcome this limitation with a new method using stereolithography that allows tuning of the printed phantom's optical properties to match that of target tissues, accomplished by printing a mixture of polystyrene microspheres and clear photopolymer resin. We show that Mie theory can be used to design the optical properties, and demonstrate the method by fabricating a mouse phantom and imaging it using fluorescence optical diffusion tomography.
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Affiliation(s)
- Brian Z. Bentz
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Anna G. Bowen
- School of Health and Human Sciences, Purdue University, West Lafayette, Indiana 47907, USA
| | - Dergan Lin
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Daniel Ysselstein
- School of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Davin H. Huston
- School of Engineering Technology, Purdue University, West Lafayette, Indiana 47907, USA
| | | | - Kevin J. Webb
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
- Corresponding author:
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23
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Ghassemi P, Wang B, Wang J, Wang Q, Chen Y, Joshua Pfefer T. Evaluation of Mobile Phone Performance for Near-Infrared Fluorescence Imaging. IEEE Trans Biomed Eng 2016; 64:1650-1653. [PMID: 28113231 DOI: 10.1109/tbme.2016.2601014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have investigated the potential for contrast-enhanced near-infrared fluorescence imaging of tissue on a mobile phone platform. Charge-coupled device- and phone-based cameras were used to image molded and three-dimensional-printed tissue phantoms, and an ex vivo animal model. Quantitative and qualitative evaluations of image quality demonstrate the viability of this approach and elucidate variations in performance due to wavelength, pixel color, and image processing.
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Affiliation(s)
- Pejhman Ghassemi
- Center for Devices and Radiological HealthFood and Drug Administration
| | - Bohan Wang
- Department of Electrical and Computer EngineeringUniversity of Maryland
| | - Jianting Wang
- Center for Devices and Radiological HealthFood and Drug Administration
| | - Quanzeng Wang
- Center for Devices and Radiological HealthFood and Drug Administration
| | - Yu Chen
- Fischell Department of BioengineeringUniversity of Maryland
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
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