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Nouizi F, Algarawi M, Erkol H, Gulsen G. Gold nanoparticle-mediated photothermal therapy guidance with multi-wavelength photomagnetic imaging. Photodiagnosis Photodyn Ther 2024; 45:103956. [PMID: 38159834 PMCID: PMC11396545 DOI: 10.1016/j.pdpdt.2023.103956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/11/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
Difficulty in heating tumors with high spatial selectivity while protecting surrounding healthy tissues from thermal harm is a challenge for cancer photothermal treatment (PTT). To mitigate this problem, PTT mediated by photothermal agents (PTAs) has been established as a potential therapeutic technique to boost selectivity and reduce damage to surrounding healthy tissues. Various gold nanoparticles (AuNP) have been effectively utilized as PTAs, mainly using strategies to target cancerous tissue and increase selective thermal damage. Meanwhile, imaging can be used in tandem to monitor the AuNP distribution and guide the PTT. Mainly, the parameters impacting the induced temperature can be determined using simulation tools before treatment for effective PTT. However, accurate simulations can only be performed if the amount of AuNPs accumulated in the tumor is known. This study introduces Photo-Magnetic Imaging (PMI), which can appropriately recover the AuNP concentration to guide the PTT. Using multi-wavelength measurements, PMI can provide AuNP concentration based on their distinct absorption spectra. Tissue-simulating phantom studies are conducted to demonstrate the potential of PMI in recovering AuNP concentration for PTT planning. The recovered AuNP concentration is used to model the temperature increase accurately in a small inclusion representing tumor using a multiphysics solver that takes into account the light propagation and heat diffusion in turbid media.
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Affiliation(s)
- Farouk Nouizi
- Department of Radiological Sciences, University of California Irvine, USA
| | - Maha Algarawi
- Department of Physics, Imam Mohammad Ibn Saud Islamic University (IMSIU), Saudi Arabia
| | - Hakan Erkol
- Department of Physics, Bogazici University, Turkey
| | - Gultekin Gulsen
- Department of Radiological Sciences, University of California Irvine, USA.
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Algarawi M, Saraswatula JS, Pathare RR, Zhang Y, Shah GA, Eresen A, Gulsen G, Nouizi F. Self-Guided Algorithm for Fast Image Reconstruction in Photo-Magnetic Imaging: Artificial Intelligence-Assisted Approach. Bioengineering (Basel) 2024; 11:126. [PMID: 38391612 PMCID: PMC10886351 DOI: 10.3390/bioengineering11020126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/16/2024] [Accepted: 01/25/2024] [Indexed: 02/24/2024] Open
Abstract
Previously, we introduced photomagnetic imaging (PMI) that synergistically utilizes laser light to slightly elevate the tissue temperature and magnetic resonance thermometry (MRT) to measure the induced temperature. The MRT temperature maps are then converted into absorption maps using a dedicated PMI image reconstruction algorithm. In the MRT maps, the presence of abnormalities such as tumors would create a notable high contrast due to their higher hemoglobin levels. In this study, we present a new artificial intelligence-based image reconstruction algorithm that improves the accuracy and spatial resolution of the recovered absorption maps while reducing the recovery time. Technically, a supervised machine learning approach was used to detect and delineate the boundary of tumors directly from the MRT maps based on their temperature contrast to the background. This information was further utilized as a soft functional a priori in the standard PMI algorithm to enhance the absorption recovery. Our new method was evaluated on a tissue-like phantom with two inclusions representing tumors. The reconstructed absorption map showed that the well-trained neural network not only increased the PMI spatial resolution but also improved the accuracy of the recovered absorption to as low as a 2% percentage error, reduced the artifacts by 15%, and accelerated the image reconstruction process approximately 9-fold.
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Affiliation(s)
- Maha Algarawi
- Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13318, Saudi Arabia
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Janaki S Saraswatula
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Rajas R Pathare
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Yang Zhang
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Gyanesh A Shah
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Aydin Eresen
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Gultekin Gulsen
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
- Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA 92697, USA
| | - Farouk Nouizi
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California Irvine, Irvine, CA 92697, USA
- Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA 92697, USA
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Nouizi F, Algarawi M, Erkol H, Luk A, Gulsen G. Multiwavelength photo-magnetic imaging algorithm improved for direct chromophore concentration recovery using spectral constraints. APPLIED OPTICS 2021; 60:10855-10861. [PMID: 35200850 DOI: 10.1364/ao.439250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/12/2021] [Indexed: 06/14/2023]
Abstract
Multiwavelength photo-magnetic imaging (PMI) is a novel combination of diffuse optics and magnetic resonance imaging, to the best of our knowledge, that yields tissue chromophore concentration maps with high resolution and quantitative accuracy. Here, we present the first experimental results, to the best of our knowledge, obtained using a spectrally constrained PMI image reconstruction method, where chromophore concentration maps are directly recovered, unlike the conventional two-step approach that requires an intermediate step of reconstructing wavelength-dependent absorption coefficient maps. The imposition of the prior spectral information into the PMI inverse problem improves the reconstructed image quality and allows recovery of highly quantitative concentration maps, which are crucial for effective cancer detection and characterization. The obtained results demonstrate the higher performance of the direct reconstruction method. Indeed, the reconstructed concentration maps are not only of higher quality but also obtained approximately 2 times faster than the conventional method.
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Algarawi M, Erkol H, Luk A, Ha S, Unlu MB, Gulsen G, Nouizi F. Multi-Wavelength Photo-Magnetic Imaging System for Photothermal Therapy Guidance. Lasers Surg Med 2021; 53:713-721. [PMID: 33169857 PMCID: PMC8107183 DOI: 10.1002/lsm.23350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 09/24/2020] [Accepted: 10/26/2020] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVES In photothermal therapy, cancerous tissue is treated by the heat generated from absorbed light energy. For effective photothermal therapy, the parameters affecting the induced temperature should be determined before the treatment by modeling the increase in temperature via numerical simulations. However, accurate simulations can only be achieved when utilizing the accurate optical, thermal, and physiological properties of the treated tissue. Here, we propose a multi-wavelength photo-magnetic imaging (PMI) technique that provides quantitative and spatially resolved tissue optical absorption maps at any wavelength within the near-infrared (NIR) window to assist accurate photothermal therapy planning. STUDY DESIGN/MATERIALS AND METHODS The study was conducted using our recently developed multi-wavelength PMI system, which operates at four laser wavelengths (760, 808, 860, and 980 nm). An agar tissue-simulating phantom containing water, lipid, and ink was illuminated using these wavelengths, and the slight internal laser-induced temperature rise was measured using magnetic resonance thermometry (MRT). The phantom optical absorption was recovered at the used wavelengths using our dedicated PMI image reconstruction algorithm. These absorption maps were then used to resolve the concentration of the tissue chromophores, and thus deduce its optical absorption spectrum in the NIR region based on the Beer-Lambert law. RESULTS The optical absorption of the phantom was successfully recovered at the used four wavelengths with an average error of ~1.9%. The recovered absorption coefficient was then used to simulate temperature variations inside the phantom. A comparison between the modeled temperature maps and the MRT measured ones showed that these maps are in a good agreement with an average pseudo R2 statistic of 0.992. These absorption values were used to successfully recover the concentration of the used chromophores. Finally, these concentrations are used to accurately calculate the total absorption spectrum of the phantom in the NIR spectral window with an average error as low as ~2.3%. CONCLUSIONS Multi-wavelength PMI demonstrated a great ability to assess the distribution of tissue chromophores, thus providing its total absorption at any wavelength within the NIR spectral range. Therefore, applications of photothermal therapy applied at NIR wavelengths can benefit from the absorption spectrum recovered by PMI to determine important parameters such as laser power as well as the laser exposure time needed to attain a specific increase in temperature prior to treatment. Lasers Surg. Med. 00:00-00, 2020. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Maha Algarawi
- Center for Functional Onco-Imaging, University of California Irvine, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
| | - Hakan Erkol
- Department of Physics, Bogazici University, Istanbul, 34342, Turkey
| | - Alex Luk
- Center for Functional Onco-Imaging, University of California Irvine, Irvine, California 92697, USA
| | - Seunghoon Ha
- Philips Healthcare, Pewaukee, Wisconsin 53072, USA
| | | | - Gultekin Gulsen
- Center for Functional Onco-Imaging, University of California Irvine, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
- Department of Radiological Sciences, University of California Irvine, Irvine, California 92697, USA
| | - Farouk Nouizi
- Center for Functional Onco-Imaging, University of California Irvine, Irvine, California 92697, USA
- Department of Radiological Sciences, University of California Irvine, Irvine, California 92697, USA
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Algarawi M, Erkol H, Luk A, Ha S, Ünlü MB, Gulsen G, Nouizi F. Resolving tissue chromophore concentration at MRI resolution using multi-wavelength photo-magnetic imaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:4244-4254. [PMID: 32923039 PMCID: PMC7449711 DOI: 10.1364/boe.397538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/24/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Photo-magnetic imaging (PMI) is an emerging optical imaging modality that showed great performance on providing absorption maps with high resolution and quantitative accuracy. As a multi-modality technology, PMI warms up the imaged object using a near infrared laser while temperature variation is measured using magnetic resonance imaging. By probing tissue at multiple wavelengths, concentration of the main tissue chromophores such as oxy- and deoxy-hemoglobin, lipid, and water are obtained then used to derive functional parameters such as total hemoglobin concentration and relative oxygen saturation. In this paper, we present a multi-wavelength PMI system that was custom-built to host five different laser wavelengths. After recovering the high-resolution absorption maps, a least-squared minimization process was used to resolve the different chromophore concentration. The performance of the system was experimentally tested on a phantom with two different dyes. Their concentrations were successfully assessed with high spatial resolution and average accuracy of nearly 80%.
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Affiliation(s)
- Maha Algarawi
- Center for Functional Onco-Imaging, University of California Irvine, CA 92697, USA
- Department of Physics and Astronomy, University of California Irvine, CA 92697, USA
| | - Hakan Erkol
- Department of Physics, Bogazici University, Istanbul, Turkey
| | - Alex Luk
- Center for Functional Onco-Imaging, University of California Irvine, CA 92697, USA
| | | | - Mehmet B. Ünlü
- Department of Physics, Bogazici University, Istanbul, Turkey
| | - Gultekin Gulsen
- Center for Functional Onco-Imaging, University of California Irvine, CA 92697, USA
- Department of Physics and Astronomy, University of California Irvine, CA 92697, USA
- Department of Radiological Sciences, University of California Irvine, CA 92697, USA
| | - Farouk Nouizi
- Center for Functional Onco-Imaging, University of California Irvine, CA 92697, USA
- Department of Radiological Sciences, University of California Irvine, CA 92697, USA
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Luk A, Nouizi F, Erkol H, Unlu MB, Gulsen G. Ex vivo validation of photo-magnetic imaging. OPTICS LETTERS 2017; 42:4171-4174. [PMID: 29028040 PMCID: PMC6855589 DOI: 10.1364/ol.42.004171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/14/2017] [Indexed: 05/18/2023]
Abstract
We recently introduced a new high-resolution diffuse optical imaging technique termed photo-magnetic imaging (PMI), which utilizes magnetic resonance thermometry (MRT) to monitor the 3D temperature distribution induced in a medium illuminated with a near-infrared light. The spatiotemporal temperature distribution due to light absorption can be accurately estimated using a combined photon propagation and heat diffusion model. High-resolution optical absorption images are then obtained by iteratively minimizing the error between the measured and modeled temperature distributions. We have previously demonstrated the feasibility of PMI with experimental studies using tissue simulating agarose phantoms. In this Letter, we present the preliminary ex vivo PMI results obtained with a chicken breast sample. Similarly to the results obtained on phantoms, the reconstructed images reveal that PMI can quantitatively resolve an inclusion with a 3 mm diameter embedded deep in a biological tissue sample with only 10% error. These encouraging results demonstrate the high performance of PMI in ex vivo biological tissue and its potential for in vivo imaging.
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Affiliation(s)
- Alex Luk
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, California 92697, USA
| | - Farouk Nouizi
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, California 92697, USA
| | - Hakan Erkol
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, California 92697, USA
| | - Mehmet B. Unlu
- Department of Physics, Bogazici University, Bebek, Istanbul, Turkey
| | - Gultekin Gulsen
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, California 92697, USA
- Department of Biomedical Engineering, University of California, Irvine, California 92697, USA
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Orza A, Yang Y, Feng T, Wang X, Wu H, Li Y, Yang L, Tang X, Mao H. A nanocomposite of Au-AgI core/shell dimer as a dual-modality contrast agent for x-ray computed tomography and photoacoustic imaging. Med Phys 2016; 43:589. [PMID: 26745951 DOI: 10.1118/1.4939062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop a core/shell nanodimer of gold (core) and silver iodine (shell) as a dual-modal contrast-enhancing agent for biomarker targeted x-ray computed tomography (CT) and photoacoustic imaging (PAI) applications. METHODS The gold and silver iodine core/shell nanodimer (Au/AgICSD) was prepared by fusing together components of gold, silver, and iodine. The physicochemical properties of Au/AgICSD were then characterized using different optical and imaging techniques (e.g., HR- transmission electron microscope, scanning transmission electron microscope, x-ray photoelectron spectroscopy, energy-dispersive x-ray spectroscopy, Z-potential, and UV-vis). The CT and PAI contrast-enhancing effects were tested and then compared with a clinically used CT contrast agent and Au nanoparticles. To confer biocompatibility and the capability for efficient biomarker targeting, the surface of the Au/AgICSD nanodimer was modified with the amphiphilic diblock polymer and then functionalized with transferrin for targeting transferrin receptor that is overexpressed in various cancer cells. Cytotoxicity of the prepared Au/AgICSD nanodimer was also tested with both normal and cancer cell lines. RESULTS The characterizations of prepared Au/AgI core/shell nanostructure confirmed the formation of Au/AgICSD nanodimers. Au/AgICSD nanodimer is stable in physiological conditions for in vivo applications. Au/AgICSD nanodimer exhibited higher contrast enhancement in both CT and PAI for dual-modality imaging. Moreover, transferrin functionalized Au/AgICSD nanodimer showed specific binding to the tumor cells that have a high level of expression of the transferrin receptor. CONCLUSIONS The developed Au/AgICSD nanodimer can be used as a potential biomarker targeted dual-modal contrast agent for both or combined CT and PAI molecular imaging.
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Affiliation(s)
- Anamaria Orza
- Department of Radiology and Imaging Sciences and Center for Systems Imaging, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Yi Yang
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Ting Feng
- Department of Biomedical Engineering, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
| | - Xueding Wang
- Department of Biomedical Engineering, University of Michigan School of Medicine, Ann Arbor, Michigan 48109
| | - Hui Wu
- Department of Radiology and Imaging Sciences and Center for Systems Imaging, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Yuancheng Li
- Department of Radiology and Imaging Sciences and Center for Systems Imaging, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Lily Yang
- Department of Surgery, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Xiangyang Tang
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Hui Mao
- Department of Radiology and Imaging Sciences and Center for Systems Imaging, Emory University School of Medicine, Atlanta, Georgia 30322
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Nouizi F, Erkol H, Luk A, Marks M, Unlu MB, Gulsen G. An accelerated photo-magnetic imaging reconstruction algorithm based on an analytical forward solution and a fast Jacobian assembly method. Phys Med Biol 2016; 61:7448-7465. [PMID: 27694717 DOI: 10.1088/0031-9155/61/20/7448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We previously introduced photo-magnetic imaging (PMI), an imaging technique that illuminates the medium under investigation with near-infrared light and measures the induced temperature increase using magnetic resonance thermometry (MRT). Using a multiphysics solver combining photon migration and heat diffusion, PMI models the spatiotemporal distribution of temperature variation and recovers high resolution optical absorption images using these temperature maps. In this paper, we present a new fast non-iterative reconstruction algorithm for PMI. This new algorithm uses analytic methods during the resolution of the forward problem and the assembly of the sensitivity matrix. We validate our new analytic-based algorithm with the first generation finite element method (FEM) based reconstruction algorithm previously developed by our team. The validation is performed using, first synthetic data and afterwards, real MRT measured temperature maps. Our new method accelerates the reconstruction process 30-fold when compared to a single iteration of the FEM-based algorithm.
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Affiliation(s)
- F Nouizi
- Department of Radiological Sciences, Tu and Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA
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Nouizi F, Erkol H, Luk A, Unlu MB, Gulsen G. Real-time photo-magnetic imaging. BIOMEDICAL OPTICS EXPRESS 2016; 7:3899-3904. [PMID: 27867701 PMCID: PMC5102518 DOI: 10.1364/boe.7.003899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/07/2016] [Accepted: 08/08/2016] [Indexed: 05/25/2023]
Abstract
We previously introduced a new high resolution diffuse optical imaging modality termed, photo-magnetic imaging (PMI). PMI irradiates the object under investigation with near-infrared light and monitors the variations of temperature using magnetic resonance thermometry (MRT). In this paper, we present a real-time PMI image reconstruction algorithm that uses analytic methods to solve the forward problem and assemble the Jacobian matrix much faster. The new algorithm is validated using real MRT measured temperature maps. In fact, it accelerates the reconstruction process by more than 250 times compared to a single iteration of the FEM-based algorithm, which opens the possibility for the real-time PMI.
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Affiliation(s)
- Farouk Nouizi
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - Hakan Erkol
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
- Department of Physics, Bogazici University, Bebek, 34342, Istanbul, Turkey
| | - Alex Luk
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Mehmet B. Unlu
- Department of Physics, Bogazici University, Bebek, 34342, Istanbul, Turkey
| | - Gultekin Gulsen
- Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
- Department of Biomedical Engineering, University of California, Irvine, CA, USA
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Nouizi F, Luk A, Thayer D, Lin Y, Ha S, Gulsen G. Experimental validation of a high-resolution diffuse optical imaging modality: photomagnetic imaging. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:16009. [PMID: 26790644 PMCID: PMC4719037 DOI: 10.1117/1.jbo.21.1.016009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/11/2015] [Indexed: 05/25/2023]
Abstract
We present experimental results that validate our imaging technique termed photomagnetic imaging (PMI). PMI illuminates the medium under investigation with a near-infrared light and measures the induced temperature increase using magnetic resonance imaging. A multiphysics solver combining light and heat propagation is used to model spatiotemporal distribution of temperature increase. Furthermore, a dedicated PMI reconstruction algorithm has been developed to reveal high-resolution optical absorption maps from temperature measurements. Being able to perform measurements at any point within the medium, PMI overcomes the limitations of conventional diffuse optical imaging. We present experimental results obtained on agarose phantoms mimicking biological tissue with inclusions having either different sizes or absorption contrasts, located at various depths. The reconstructed images show that PMI can successfully resolve these inclusions with high resolution and recover their absorption coefficient with high-quantitative accuracy. Even a 1-mm inclusion located 6-mm deep is recovered successfully and its absorption coefficient is underestimated by only 32%. The improved PMI system presented here successfully operates under the maximum skin exposure limits defined by the American National Standards Institute, which opens up the exciting possibility of its future clinical use for diagnostic purposes.
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Affiliation(s)
- Farouk Nouizi
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
| | - Alex Luk
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
| | - Dave Thayer
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
- Washington University in St. Louis, Mallinckrodt Institute of Radiology, 510 South Kingshighway Boulevard, St. Louis, Missouri 63110, United States
| | - Yuting Lin
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
- Massachusetts General Hospital and Harvard Medical School, Department of Radiation Oncology, 55 Fruit Street, Boston, Massachusetts 02144, United States
| | - Seunghoon Ha
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
- Philips Healthcare, N27 West 23676 Paul Road, Pewaukee, Wisconsin 53072, United States
| | - Gultekin Gulsen
- University of California, Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, 164 Irvine Hall, Irvine, California, United States
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Erkol H, Nouizi F, Luk A, Unlu MB, Gulsen G. Comprehensive analytical model for CW laser induced heat in turbid media. OPTICS EXPRESS 2015; 23:31069-31084. [PMID: 26698736 PMCID: PMC4692257 DOI: 10.1364/oe.23.031069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/07/2015] [Accepted: 10/10/2015] [Indexed: 05/29/2023]
Abstract
In this work, we present a new analytical approach to model continuous wave laser induced temperature in highly homogeneous turbid media. First, the diffusion equation is used to model light transport and a comprehensive solution is derived analytically by obtaining a special Greens' function. Next, the time-dependent bio-heat equation is used to describe the induced heat increase and propagation within the medium. The bio-heat equation is solved analytically utilizing the separation of variables technique. Our theoretical model is successfully validated using numerical simulations and experimental studies with agarose phantoms and ex-vivo chicken breast samples. The encouraging results show that our method can be implemented as a simulation tool to determine important laser parameters that govern the magnitude of temperature rise within homogenous biological tissue or organs.
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Affiliation(s)
- Hakan Erkol
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA,
USA
| | - Farouk Nouizi
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA,
USA
| | - Alex Luk
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA,
USA
| | - Mehmet Burcin Unlu
- Department of Physics, Bogazici University, Bebek, 34342, Istanbul,
Turkey
| | - Gultekin Gulsen
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA,
USA
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Abstract
In this work, we introduce an analytical method to solve the diffusion equation in a cylindrical geometry. This method is based on an integral approach to derive the Green's function for specific boundary conditions. Using our approach, we obtain comprehensive analytical solutions with the Robin boundary condition for diffuse optical imaging in both two and three dimensions. The solutions are expressed in terms of the optical properties of tissue and the amplitude and position of the light source. Our method not only works well inside the tissue but provides very accurate results near the tissue boundaries as well. The results obtained by our method are first compared with those obtained by a conventional analytical method then validated using numerical simulations. Our new analytical method allows not only implementation of any boundary condition for a specific problem but also fast simulation of light propagation making it very suitable for iterative image reconstruction algorithms.
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Affiliation(s)
- H Erkol
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
- Department of Physics, Bogazici University, Bebek, 34342, Istanbul, Turkey
| | - F Nouizi
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
| | - M B Unlu
- Department of Physics, Bogazici University, Bebek, 34342, Istanbul, Turkey
| | - G Gulsen
- Center for Functional Onco Imaging, Department of Radiological Sciences, University of California, Irvine, CA, USA
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