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Rodriguez AJ, Vasudevan S, Farahmand M, Weininger S, Vogt WC, Scully CG, Ramella-Roman J, Pfefer TJ. Tissue mimicking materials and finger phantom design for pulse oximetry. BIOMEDICAL OPTICS EXPRESS 2024; 15:2308-2327. [PMID: 38633081 PMCID: PMC11019708 DOI: 10.1364/boe.518967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/03/2024] [Accepted: 03/03/2024] [Indexed: 04/19/2024]
Abstract
Pulse oximetry represents a ubiquitous clinical application of optics in modern medicine. Recent studies have raised concerns regarding the potential impact of confounders, such as variable skin pigmentation and perfusion, on blood oxygen saturation measurement accuracy in pulse oximeters. Tissue-mimicking phantom testing offers a low-cost, well-controlled solution for characterizing device performance and studying potential error sources, which may thus reduce the need for costly in vivo trials. The purpose of this study was to develop realistic phantom-based test methods for pulse oximetry. Material optical and mechanical properties were reviewed, selected, and tuned for optimal biological relevance, e.g., oxygenated tissue absorption and scattering, strength, elasticity, hardness, and other parameters representing the human finger's geometry and composition, such as blood vessel size and distribution, and perfusion. Relevant anatomical and physiological properties are summarized and implemented toward the creation of a preliminary finger phantom. To create a preliminary finger phantom, we synthesized a high-compliance silicone matrix with scatterers for embedding flexible tubing and investigated the addition of these scatterers to novel 3D printing resins for optical property control without altering mechanical stability, streamlining the production of phantoms with biologically relevant characteristics. Phantom utility was demonstrated by applying dynamic, pressure waveforms to produce tube volume change and resultant photoplethysmography (PPG) signals. 3D printed phantoms achieved more biologically relevant conditions compared to molded phantoms. These preliminary results indicate that the phantoms show strong potential to be developed into tools for evaluating pulse oximetry performance. Gaps, recommendations, and strategies are presented for continued phantom development.
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Affiliation(s)
- Andres J. Rodriguez
- Department of Biomedical Engineering, Florida International University, Miami. Florida, 33174, USA
| | - Sandhya Vasudevan
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Masoud Farahmand
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Sandy Weininger
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - William C. Vogt
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Christopher G. Scully
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Jessica Ramella-Roman
- Department of Biomedical Engineering, Florida International University, Miami. Florida, 33174, USA
| | - T. Joshua Pfefer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, USA
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Nanotechnology as a Versatile Tool for 19F-MRI Agent’s Formulation: A Glimpse into the Use of Perfluorinated and Fluorinated Compounds in Nanoparticles. Pharmaceutics 2022; 14:pharmaceutics14020382. [PMID: 35214114 PMCID: PMC8874484 DOI: 10.3390/pharmaceutics14020382] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 02/04/2023] Open
Abstract
Simultaneously being a non-radiative and non-invasive technique makes magnetic resonance imaging (MRI) one of the highly sought imaging techniques for the early diagnosis and treatment of diseases. Despite more than four decades of research on finding a suitable imaging agent from fluorine for clinical applications, it still lingers as a challenge to get the regulatory approval compared to its hydrogen counterpart. The pertinent hurdle is the simultaneous intrinsic hydrophobicity and lipophobicity of fluorine and its derivatives that make them insoluble in any liquids, strongly limiting their application in areas such as targeted delivery. A blossoming technique to circumvent the unfavorable physicochemical characteristics of perfluorocarbon compounds (PFCs) and guarantee a high local concentration of fluorine in the desired body part is to encapsulate them in nanosystems. In this review, we will be emphasizing different types of nanocarrier systems studied to encapsulate various PFCs and fluorinated compounds, headway to be applied as a contrast agent (CA) in fluorine-19 MRI (19F MRI). We would also scrutinize, especially from studies over the last decade, the different types of PFCs and their specific applications and limitations concerning the nanoparticle (NP) system used to encapsulate them. A critical evaluation for future opportunities would be speculated.
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Chen C, Ahmed M, Häfner T, Klämpfl F, Stelzle F, Schmidt M. Fabrication of a turbid optofluidic phantom device with tunable μa and μ's to simulate cutaneous vascular perfusion. Sci Rep 2016; 6:30567. [PMID: 27457535 PMCID: PMC4960568 DOI: 10.1038/srep30567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/27/2016] [Indexed: 11/15/2022] Open
Abstract
Microfluidic devices are oftenly used to calibrate the imaging reconstruction, because they simulate the morphology of microvasculature. However, for lack of optical properties in microfluidics, the functional recovery of oximetry information cannot be verified. In this work, we describe the fabrication of a novel turbid optofluidic tissue phantom. It is designed to mimic the vascular perfusion and the turbid nature of cutaneous tissue. This phantom contains an interior hollow microfluidic structure with a diameter of ϕave = 50 μm. The microfluidic structure includes the geometry of an inlet, a river-like assay and an outlet. This structure can be perfused by hemoglobin solution to mimic the cutaneous micro-circulation. The multiple-layered phantom matrices exhibit the representative optical parameters of human skin cutis, namely the absorption coefficient μa and the reduced scattering coefficient . The geometry of the generated microfluidic structure is investigated by using Spectral-Domain Optical Coherence Tomography. This optofluidic phantom bridges the gap between tissue equivalent phantoms and Lab-On-Chip devices. Perspectively, this device can be used to calibrate a variety of optical angiographic imaging approaches.
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Affiliation(s)
- Chen Chen
- Chair of Photonic Technologies, Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, D-91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Str. 6, D-91052 Erlangen, Germany
| | - Midhat Ahmed
- Chair of Photonic Technologies, Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, D-91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Str. 6, D-91052 Erlangen, Germany
| | - Tom Häfner
- Chair of Photonic Technologies, Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, D-91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Str. 6, D-91052 Erlangen, Germany
| | - Florian Klämpfl
- Chair of Photonic Technologies, Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, D-91052 Erlangen, Germany
| | - Florian Stelzle
- Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Str. 6, D-91052 Erlangen, Germany
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander Universität Erlangen-Nürnberg, Glückstr. 11, D-91054 Erlangen, Germany
| | - Michael Schmidt
- Chair of Photonic Technologies, Friedrich-Alexander Universität Erlangen-Nürnberg, Konrad-Zuse-Str. 3/5, D-91052 Erlangen, Germany
- Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Str. 6, D-91052 Erlangen, Germany
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Hallac RR, Zhou H, Pidikiti R, Song K, Stojadinovic S, Zhao D, Solberg T, Peschke P, Mason RP. Correlations of noninvasive BOLD and TOLD MRI with pO2 and relevance to tumor radiation response. Magn Reson Med 2013; 71:1863-73. [PMID: 23813468 DOI: 10.1002/mrm.24846] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 05/21/2013] [Accepted: 05/24/2013] [Indexed: 12/21/2022]
Abstract
PURPOSE To examine the potential use of blood oxygenation level dependent (BOLD) and tissue oxygenation level dependent (TOLD) contrast MRI to assess tumor oxygenation and predict radiation response. METHODS BOLD and TOLD MRI were performed on Dunning R3327-AT1 rat prostate tumors during hyperoxic gas breathing challenge at 4.7 T. Animals were divided into two groups. In Group 1 (n = 9), subsequent (19) F MRI based on spin lattice relaxation of hexafluorobenzene reporter molecule provided quantitative oximetry for comparison. For Group 2 rats (n = 13) growth delay following a single dose of 30 Gy was compared with preirradiation BOLD and TOLD assessments. RESULTS Oxygen (100%O2 ) and carbogen (95%O2 /5%CO2 ) challenge elicited similar BOLD, TOLD and pO2 responses. Strong correlations were observed between BOLD or R2* response and quantitative (19) F pO2 measurements. TOLD response showed a general trend with weaker correlation. Irradiation caused a significant tumor growth delay and tumors with larger changes in TOLD and R1 values upon oxygen breathing exhibited significantly increased tumor growth delay. CONCLUSION These results provide further insight into the relationships between oxygen sensitive (BOLD/TOLD) MRI and tumor pO2 . Moreover, a larger increase in R1 response to hyperoxic gas challenge coincided with greater tumor growth delay following irradiation.
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Affiliation(s)
- Rami R Hallac
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Yu JX, Hallac RR, Chiguru S, Mason RP. New frontiers and developing applications in 19F NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 70:25-49. [PMID: 23540575 PMCID: PMC3613763 DOI: 10.1016/j.pnmrs.2012.10.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/23/2012] [Indexed: 05/06/2023]
Affiliation(s)
- Jian-Xin Yu
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Rami R. Hallac
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Srinivas Chiguru
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
| | - Ralph P. Mason
- Laboratory of Prognostic Radiology, Division of Advanced Radiological Sciences, Department of Radiology, UT Southwestern Medical Center, Dallas, Texas
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Baete SH, Vandecasteele J, De Deene Y. 19F MRI oximetry: simulation of perfluorocarbon distribution impact. Phys Med Biol 2011; 56:2535-57. [PMID: 21444970 DOI: 10.1088/0031-9155/56/8/013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In (19)F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in (19)F MRI oximetry through a computer simulation. The simulation studies the correspondence between (19)F measured (pO(FNMR)(2)) and actual tissue oxygen tension (pO(2)) for several tissue perfluorocarbon distributions. For this, a Krogh tissue model is implemented which incorporates the presence of perfluorocarbons in blood and tissue. That is, in tissue the perfluorocarbons are distributed homogeneously according to Gaussian diffusion profiles, or the perfluorocarbons are concentrated in the capillary wall. Using these distributions, the oxygen tension in the simulation volume is calculated. The simulated mean oxygen tension is then compared with pO(FNMR)(2), the (19)F MRI-based measure of pO(2) and with pO(0)(2), pO(2) in the absence of perfluorocarbons. The agreement between pO(FNMR)(2) and actual pO(2) is influenced by vascular density and perfluorocarbon distribution. The presence of perfluorocarbons generally gives rise to a pO(2) increase in tissue. This effect is enhanced when perfluorocarbons are also present in blood. Only the homogeneous perfluorocarbon distribution in tissue with no perfluorocarbons in blood guarantees small deviations of pO(FNMR)(2) from pO(2). Hence, perfluorocarbon distribution in tissue and blood has a serious impact on the reliability of (19)F MRI-based measures of oxygen tension. In addition, the presence of perfluorocarbons influences the actual oxygen tension. This finding may be of great importance for further development of (19)F MRI oximetry.
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Affiliation(s)
- S H Baete
- Department of Radiation Oncology and Experimental Cancer Research, Ghent University, De Pintelaan 185, 9000 Gent, Belgium.
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