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Paik J, Kim D, Kim H, Kim HS. Numerical study on the three-dimensional temperature distribution according to laser conditions in photothermal therapy of peri-implantitis. Int J Implant Dent 2024; 10:19. [PMID: 38656614 PMCID: PMC11043321 DOI: 10.1186/s40729-024-00537-y] [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: 01/25/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024] Open
Abstract
PURPOSE Dental implants have been successfully implemented as a treatment for tooth loss. However, peri-implantitis, an inflammatory reaction owing to microbial deposition around the implant, can lead to implant failure. So, it is necessary to treat peri-implantitis. Therefore, this numerical study is aimed at investigating conditions for treating peri-implantitis. METHODS Photothermal therapy, a laser treatment method, utilizes photothermal effect, in which light is converted to heat. This technique has advantage of selectively curing inflamed tissues by increasing their temperature. Accordingly, herein, photothermal effect on peri-implantitis is studied through numerical analysis with using Arrhenius damage integral and Arrhenius thermal damage ratio. RESULTS Through numerical analysis on peri-implantitis treatment, we explored temperature changes under varied laser settings (laser power, radius, irradiation time). We obtained the temperature distribution on interface of artificial tooth root and inflammation and determined whether temperature exceeds or does not exceed 47℃ to know which laser power affects alveolar bone indirectly. We defined the Arrhenius thermal damage ratio as a variable and determined that the maximum laser power that does not exceed 47℃ at the AA' line is 1.0 W. Additionally, we found that the value of the Arrhenius thermal damage ratio is 0.26 for a laser irradiation time of 100 s and 0.50 for 500 s. CONCLUSION The result of this numerical study indicates that the Arrhenius thermal damage ratio can be used as a standard for determining the treatment conditions to help assisted laser treatment for peri-implantitis in each numerical analysis scenario.
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Affiliation(s)
- Jeeyong Paik
- Department of Mechanical Engineering, Ajou University, 16499, Suwon-si, Gyeonggi-do, Korea
| | - Donghyuk Kim
- Department of Mechanical Engineering, Ajou University, 16499, Suwon-si, Gyeonggi-do, Korea
| | - Hyunjung Kim
- Department of Mechanical Engineering, Ajou University, 16499, Suwon-si, Gyeonggi-do, Korea.
| | - Hee-Sun Kim
- Department of Dentistry, SMG_SNU Boramae Medical Center, 07061, Seoul, Korea.
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Lu T, Khampang P, Beydoun A, Berezovsky A, Rohde R, Hong W, Yu B, Kerschner JE. Continuous monitoring of endotracheal tube position with near infrared light. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:035001. [PMID: 38476221 PMCID: PMC10928496 DOI: 10.1117/1.jbo.29.3.035001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/15/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024]
Abstract
Significance Endotracheal intubation is a common approach for airway management in critically ill patients. However, the position of the endotracheal tube (ETT) may be altered during the procedure due to head movements. Accidental displacement or dislodge of the ETT may reduce the airflow, leading to moderate to severe complications, and in some cases even fatality. Therefore, timely detection of changes in ETT position in the trachea is critical to ensure immediate and intermediate interventions to maintain the ETT in the proper position. Currently, there are no widely utilized tools for real-time monitoring of ETT positions. Aim The goal of this study is to develop a cost-effective and easy-to-use near-infrared (NIR) device, named Opt-ETT, capable of continuously monitoring the ETT position in the trachea of a patient. Approach A side-firing fiber is attached to the side of the ETT to illuminate the trachea tissue with NIR light, and a detector board containing five phototransistors is affixed to the chest skin to measure the intensity of diffusely transmitted light. Displacement of the ETT is estimated using second-order polynomial fitting to the ratios of the phototransistor readings. Monte Carlo simulations, ex vivo experiment on porcine tissue, and in vivo experiments using a swine model have been conducted to assess the feasibility of the device. Results The design of the Opt-ETT device has been verified by the Monte Carlo simulations and ex vivo experiment. The estimation of displacement from in vivo experiments using the Opt-ETT exhibited a high degree of agreement with that measured by a reference sensor, with a discrepancy between - 1.0 to + 1.5 mm within a displacement range from - 15 to + 15 mm . Conclusions The Opt-ETT device provides a potentially cost-effective solution for real-time and continuous monitoring of ETT position in patient during an intubation procedure.
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Affiliation(s)
- Tongtong Lu
- Marquette University, Medical College of Wisconsin, Joint Department of Biomedical Engineering, Milwaukee, Wisconsin, United States
| | - Pawjai Khampang
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
| | - Ahmed Beydoun
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
| | - Anna Berezovsky
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
| | - Rebecca Rohde
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
| | - Wenzhou Hong
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
| | - Bing Yu
- Marquette University, Medical College of Wisconsin, Joint Department of Biomedical Engineering, Milwaukee, Wisconsin, United States
| | - Joseph E. Kerschner
- Medical College of Wisconsin, Department of Otolaryngology and Communication Sciences, Milwaukee, Wisconsin, United States
- Medical College of Wisconsin, Department of Microbiology and Immunology, Milwaukee, Wisconsin, United States
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Li K, Wu Q, Feng S, Zhao H, Jin W, Qiu H, Gu Y, Chen D. In situ detection of human glioma based on tissue optical properties using diffuse reflectance spectroscopy. JOURNAL OF BIOPHOTONICS 2023; 16:e202300195. [PMID: 37589177 DOI: 10.1002/jbio.202300195] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/18/2023] [Accepted: 08/15/2023] [Indexed: 08/18/2023]
Abstract
Safely maximizing brain cancer removal without injuring adjacent healthy tissue is crucial for optimal treatment outcomes. However, it is challenging to distinguish cancer from noncancer intraoperatively. This study aimed to explore the feasibility of diffuse reflectance spectroscopy (DRS) as a label-free and real-time detection technology for discrimination between brain cancer and noncancer tissues. Fifty-five fresh cancer and noncancer specimens from 19 brain surgeries were measured with DRS, and the results were compared with co-registered clinical standard histopathology. Tissue optical properties were quantitatively obtained from the diffuse reflectance spectra and compared among different types of brain tissues. A machine learning-based classifier was trained to differentiate cancerous versus noncancerous tissues. Our method could achieve a sensitivity of 93% and specificity of 95% for discriminating high-grade glioma from normal white matter. Our results showed that DRS has the potential to be used for label-free, real-time in vivo cancer detection during brain surgery.
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Affiliation(s)
- Kerui Li
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
| | - Qijia Wu
- Department of Neurosurgery, First Medical Center of PLA General Hospital, Beijing, China
| | - Shiyu Feng
- Department of Neurosurgery, First Medical Center of PLA General Hospital, Beijing, China
| | - Hongyou Zhao
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
| | - Wei Jin
- Department of Pathology, Chinese PLA General Hospital, Beijing, China
| | - Haixia Qiu
- Department of Laser Medicine, First Medical Center of PLA General Hospital, Beijing, China
| | - Ying Gu
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
- Department of Laser Medicine, First Medical Center of PLA General Hospital, Beijing, China
- Precision Laser Medical Diagnosis and Treatment Innovation Unit, Chinese Academy of Medical Sciences, Beijing, China
| | - Defu Chen
- School of Medical Technology, Beijing Institute of Technology, Beijing, China
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Minakawa M, Wares MA, Nakano K, Haneishi H, Aizu Y, Hayasaki Y, Ikeda T, Nagahara H, Nishidate I. Measuring and imaging of transcutaneous bilirubin, hemoglobin, and melanin based on diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:107001. [PMID: 37915398 PMCID: PMC10616887 DOI: 10.1117/1.jbo.28.10.107001] [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: 07/11/2023] [Revised: 09/19/2023] [Accepted: 10/13/2023] [Indexed: 11/03/2023]
Abstract
Significance Evaluation of biological chromophore levels is useful for detection of various skin diseases, including cancer, monitoring of health status and tissue metabolism, and assessment of clinical and physiological vascular functions. Clinically, it is useful to assess multiple different chromophores in vivo with a single technique or instrument. Aim To investigate the possibility of estimating the concentration of four chromophores, bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin from diffuse reflectance spectra in the visible region. Approach A new diffuse reflectance spectroscopic method based on the multiple regression analysis aided by Monte Carlo simulations for light transport was developed to quantify bilirubin, oxygenated hemoglobin, deoxygenated hemoglobin, and melanin. Three different experimental animal models were used to induce hyperbilirubinemia, hypoxemia, and melanogenesis in rats. Results The estimated bilirubin concentration increased after ligation of the bile duct and reached around 18 mg / dl at 50 h after the onset of ligation, which corresponds to the reference value of bilirubin measured by a commercially available transcutaneous bilirubin meter. The concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin decreased and increased, respectively, as the fraction of inspired oxygen decreased. Consequently, the tissue oxygen saturation dramatically decreased. The time course of melanin concentration after depilation of skin on the back of rats was indicative of the supply of melanosomes produced by melanocytes of hair follicles to the growing hair shaft. Conclusions The results of our study showed that the proposed method is capable of the in vivo evaluation of percutaneous bilirubin level, skin hemodynamics, and melanogenesis in rats, and that it has potential as a tool for the diagnosis and management of hyperbilirubinemia, hypoxemia, and pigmented skin lesions.
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Affiliation(s)
- Masafumi Minakawa
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications and Systems Engineering, Tokyo, Japan
| | - Md. Abdul Wares
- Government of Bangladesh, Ministry of Fisheries and Livestock, Department of Livestock Services, Dhaka, Bangladesh
| | - Kazuya Nakano
- Seikei University, Department of Science and Technology, Faculty of Science and Technology, Tokyo, Japan
| | - Hideaki Haneishi
- Chiba University, Center for Frontier Medical Engineering, Chiba, Japan
| | - Yoshihisa Aizu
- Muroran Institute of Technology, College of Design and Manufacturing Technology, Hokkaido, Japan
| | - Yoshio Hayasaki
- Utsunomiya University, Center for Optical Research and Education, Tochigi, Japan
| | - Tetsuo Ikeda
- Fukuoka Dental College, Section of General Surgery, Division of Oral and Medical Management, Department of Medicine, Fukuoka, Japan
| | - Hajime Nagahara
- Osaka University, Institute for Datability Science, Osaka, Japan
| | - Izumi Nishidate
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications and Systems Engineering, Tokyo, Japan
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Urban BE, Subhash HM, Kilpatrick-Liverman L. Measuring changes in blood volume fraction during induced gingivitis of healthy and unhealthy populations using hyperspectral spatial frequency domain imaging: a clinical study. Sci Rep 2022; 12:18357. [PMID: 36319677 PMCID: PMC9626635 DOI: 10.1038/s41598-022-23115-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/25/2022] [Indexed: 12/31/2022] Open
Abstract
This investigation aimed to quantitatively measure the changes in inflammation of subjects with healthy and unhealthy gums during a period of induced gingivitis. A total of 30 subjects (15 healthy, 15 with gum inflammation) were enlisted and given oral exams by a dental hygienist. Baseline measurements were acquired before a 3-week period of oral hygiene abstinence. The lobene modified gingival index scoring was used for inflammation scoring and hyperspectral spatial frequency domain imaging was used to quantitatively measure oxy- and deoxygenated blood volume fraction at two time points: at Baseline and after 3 weeks of oral hygiene abstinence. We found that abstaining from oral hygiene causes a near proportional increase in oxygenated and deoxygenated blood volume fraction for healthy individuals. For individuals who started the study with mild to moderate gingivitis, increases in blood volume were mainly due to deoxygenated blood.
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Affiliation(s)
- Ben E. Urban
- grid.418753.c0000 0004 4685 452XGlobal Technology and Design Center, Colgate Palmolive Technology Center Campus, Piscataway, NJ 08854 USA
| | - Hrebesh M. Subhash
- grid.418753.c0000 0004 4685 452XGlobal Technology and Design Center, Colgate Palmolive Technology Center Campus, Piscataway, NJ 08854 USA
| | - LaTonya Kilpatrick-Liverman
- grid.418753.c0000 0004 4685 452XGlobal Technology and Design Center, Colgate Palmolive Technology Center Campus, Piscataway, NJ 08854 USA
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Fisher C, Harty J, Yee A, Li CL, Komolibus K, Grygoryev K, Lu H, Burke R, Wilson BC, Andersson-Engels S. Perspective on the integration of optical sensing into orthopedic surgical devices. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:010601. [PMID: 34984863 PMCID: PMC8727454 DOI: 10.1117/1.jbo.27.1.010601] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/23/2021] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Orthopedic surgery currently comprises over 1.5 million cases annually in the United States alone and is growing rapidly with aging populations. Emerging optical sensing techniques promise fewer side effects with new, more effective approaches aimed at improving patient outcomes following orthopedic surgery. AIM The aim of this perspective paper is to outline potential applications where fiberoptic-based approaches can complement ongoing development of minimally invasive surgical procedures for use in orthopedic applications. APPROACH Several procedures involving orthopedic and spinal surgery, along with the clinical challenge associated with each, are considered. The current and potential applications of optical sensing within these procedures are discussed and future opportunities, challenges, and competing technologies are presented for each surgical application. RESULTS Strong research efforts involving sensor miniaturization and integration of optics into existing surgical devices, including K-wires and cranial perforators, provided the impetus for this perspective analysis. These advances have made it possible to envision a next-generation set of devices that can be rigorously evaluated in controlled clinical trials to become routine tools for orthopedic surgery. CONCLUSIONS Integration of optical devices into surgical drills and burrs to discern bone/tissue interfaces could be used to reduce complication rates across a spectrum of orthopedic surgery procedures or to aid less-experienced surgeons in complex techniques, such as laminoplasty or osteotomy. These developments present both opportunities and challenges for the biomedical optics community.
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Affiliation(s)
- Carl Fisher
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - James Harty
- Cork University Hospital and South Infirmary Victoria University Hospital, Department of Orthopaedic Surgery, Cork, Ireland
| | - Albert Yee
- University of Toronto, Sunnybrook Research Institute, Department of Surgery, Holland Bone and Joint Program, Division of Orthopaedic Surgery, Sunnybrook Health Sciences; Orthopaedic Biomechanics Laboratory, Physical Sciences Platform, Toronto, Canada
| | - Celina L. Li
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - Katarzyna Komolibus
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - Konstantin Grygoryev
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - Huihui Lu
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - Ray Burke
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
| | - Brian C. Wilson
- University of Toronto, Princess Margaret Cancer Centre/University Health Network, Department of Medical Biophysics, Toronto, Canada
| | - Stefan Andersson-Engels
- Biophotonics@Tyndall, IPIC, Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland
- University College Cork, Department of Physics, Cork, Ireland
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Hohmann M, Karabayir A, Herzler P, Späth M, Klämpfl F, Schmidt M. Analysis of diffuse reflectance spectroscopy by means of Bayesian inference and separation of the parameters for scattering strength and spectral dependence of the scattering. JOURNAL OF BIOPHOTONICS 2021; 14:e202100205. [PMID: 34505403 DOI: 10.1002/jbio.202100205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/12/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
For many applications in tissue optics, knowledge of the scattering coefficient or at least the reduced scattering coefficient is essential. In addition, its spectral dependence is also an important feature, as this provides information about scatterer sizes. While the characterization of the spectral dependence should be a simple fit, experimental results show strong fluctuations even for the same tissue type. For in-vivo measurements, this problem is even greater. Therefore, it is the aim of this study to analyze the instabilities of the scattering characterizations and find a solution for it by means of Bayesian inference. In this study, this behavior is investigated using the example of diffuse reflectance spectroscopy. It can be shown that the currently used fitting functions are unstable for the fitting as both parameters for characterizing the reduced scattering coefficient describe the spectral dependence as well as the scattering strength. However, by a simple coordinate transform, a stable mathematical description of the scattering is derived. By the fact that a posteriori probability of the reduced scattering coefficient narrows down significantly with the Bayesian inference, the new fitting function is verified.
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Affiliation(s)
- Martin Hohmann
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
| | - Ayse Karabayir
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
| | - Paul Herzler
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
| | - Moritz Späth
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
| | - Florian Klämpfl
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
| | - Michael Schmidt
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Bavaria, Germany
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Affiliation(s)
- Hui Liu
- Shanxi Eye Hospital 100 Fudong St, Liu Xiang Shang Quan Xinghualing District, Taiyuan 030002, China
| | - Juan Cheng
- Shanxi Eye Hospital 100 Fudong St, Liu Xiang Shang Quan Xinghualing District, Taiyuan 030002, China
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Abdlaty R, Fang Q. Skin erythema assessment techniques. Clin Dermatol 2021; 39:591-604. [PMID: 34809765 DOI: 10.1016/j.clindermatol.2021.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Skin erythema may present owing to many causes. One of the common causes is prolonged exposure to sunrays. Other than sun exposure, skin erythema is an accompanying sign of dermatologic diseases, such as psoriasis and acne. Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Quantitative assessment of skin erythema has been the focus of several studies. The clinical standard for erythema evaluation is visual assessment; however, this standard has some deficiencies. For instance, visual assessment is subjective and ineffectual for precise color information exchange. To overcome these limitations, in the past three decades various methodologies have been developed in an attempt to achieve objective erythema assessments, such as diffuse reflectance spectroscopy and both optical and nonoptical systems. This review considers the studies published during the past three decades and discusses the performance, the mathematical tactics for computation, and the limited capabilities of erythema assessment techniques for cutaneous diseases. The achievements and limitations of the current techniques in erythema assessment are presented. The advantages and development trends of optical and nonoptical methods are presented to make the reader aware of the present technological advances and their potential for dermatological disease research.
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Affiliation(s)
- Ramy Abdlaty
- Biomedical Engineering, Military Technical College, Kobry-Elkobba, Cairo, Egypt
| | - Qiyin Fang
- Department of Engineering Physics, McMaster University, Hamilton, ONT, Canada.
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Pleskow DK, Zhang L, Turzhitsky V, Coughlan MF, Khan U, Zhang X, Sheil CJ, Glyavina M, Chen L, Shinagare S, Zakharov YN, Vitkin E, Itzkan I, Perelman LT, Qiu L. Coherent confocal light scattering spectroscopic microscopy evaluates cancer progression and aggressiveness in live cells and tissue. ACS PHOTONICS 2021; 8:2050-2059. [PMID: 34485615 PMCID: PMC8411902 DOI: 10.1021/acsphotonics.1c00217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The observation of biological structures in live cells beyond the diffraction limit with super-resolution fluorescence microscopy is limited by the ability of fluorescence probes to permeate live cells and the effect of these probes, which are often toxic, on cellular behavior. Here we present a coherent confocal light scattering and absorption spectroscopic microscopy that for the first time enables the use of large numerical aperture optics to characterize structures in live cells down to 10 nm spatial scales, well beyond the diffraction limit. Not only does this new capability allow high resolution microscopy with light scattering contrast, but it can also be used with almost any light scattering spectroscopic application which employs lenses. We demonstrate that the coherent light scattering contrast based technique allows continuous temporal tracking of the transition from non-cancerous to an early cancerous state in live cells, without exogenous markers. We also use the technique to sense differences in the aggressiveness of cancer in live cells and for label free identification of different grades of cancer in resected tumor tissues.
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Affiliation(s)
- Douglas K. Pleskow
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
- Center for Advanced Endoscopy, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Lei Zhang
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Vladimir Turzhitsky
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Mark F. Coughlan
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Umar Khan
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Xuejun Zhang
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Conor J. Sheil
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Maria Glyavina
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Liming Chen
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Shweta Shinagare
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard University
| | - Yuri N. Zakharov
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Edward Vitkin
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Irving Itzkan
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
| | - Lev T. Perelman
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
- Biological and Biomedical Sciences Program, Harvard University
| | - Le Qiu
- Center for Advanced Biomedical Imaging and Photonics, Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard University
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Algorri JF, Ochoa M, Roldán-Varona P, Rodríguez-Cobo L, López-Higuera JM. Light Technology for Efficient and Effective Photodynamic Therapy: A Critical Review. Cancers (Basel) 2021; 13:3484. [PMID: 34298707 PMCID: PMC8307713 DOI: 10.3390/cancers13143484] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/17/2021] [Accepted: 07/07/2021] [Indexed: 12/18/2022] Open
Abstract
Photodynamic therapy (PDT) is a cancer treatment with strong potential over well-established standard therapies in certain cases. Non-ionising radiation, localisation, possible repeated treatments, and stimulation of immunological response are some of the main beneficial features of PDT. Despite the great potential, its application remains challenging. Limited light penetration depth, non-ideal photosensitisers, complex dosimetry, and complicated implementations in the clinic are some limiting factors hindering the extended use of PDT. To surpass actual technological paradigms, radically new sources, light-based devices, advanced photosensitisers, measurement devices, and innovative application strategies are under extensive investigation. The main aim of this review is to highlight the advantages/pitfalls, technical challenges and opportunities of PDT, with a focus on technologies for light activation of photosensitisers, such as light sources, delivery devices, and systems. In this vein, a broad overview of the current status of superficial, interstitial, and deep PDT modalities-and a critical review of light sources and their effects on the PDT process-are presented. Insight into the technical advancements and remaining challenges of optical sources and light devices is provided from a physical and bioengineering perspective.
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Affiliation(s)
- José Francisco Algorri
- Photonics Engineering Group, University of Cantabria, 39005 Santander, Spain; (M.O.); (P.R.-V.); (J.M.L.-H.)
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL), 39011 Santander, Spain
| | - Mario Ochoa
- Photonics Engineering Group, University of Cantabria, 39005 Santander, Spain; (M.O.); (P.R.-V.); (J.M.L.-H.)
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL), 39011 Santander, Spain
| | - Pablo Roldán-Varona
- Photonics Engineering Group, University of Cantabria, 39005 Santander, Spain; (M.O.); (P.R.-V.); (J.M.L.-H.)
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL), 39011 Santander, Spain
- CIBER-bbn, Institute of Health Carlos III, 28029 Madrid, Spain;
| | | | - José Miguel López-Higuera
- Photonics Engineering Group, University of Cantabria, 39005 Santander, Spain; (M.O.); (P.R.-V.); (J.M.L.-H.)
- Instituto de Investigación Sanitaria Valdecilla (IDIVAL), 39011 Santander, Spain
- CIBER-bbn, Institute of Health Carlos III, 28029 Madrid, Spain;
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Hohmann M, Lengenfelder B, Muhr D, Späth M, Hauptkorn M, Klämpfl F, Schmidt M. Direct measurement of the scattering coefficient. BIOMEDICAL OPTICS EXPRESS 2021; 12:320-335. [PMID: 33659078 PMCID: PMC7899499 DOI: 10.1364/boe.410248] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 05/11/2023]
Abstract
In general, the measurement of the main three optical properties (µ a , µ s and g) in turbid media requires a very precise measurement of the total transmission (TT), the total reflection (TR) and the collimated transmission (CT). Furthermore, an inverse algorithm such as inverse adding doubling or inverse Monte-Carlo-simulations is required for the reconstruction of the optical properties. Despite many available methods, the error free measurement of the scattering coefficient or the g-factor still remains challenging. In this study, we present a way to directly calculate the scattering coefficient from the total and collimated transmission. To allow this, it can be shown thatT T C T is proportional to e μ s ⋅ d for a wide range of optical properties if the sample is thick enough. Moreover, a set-up is developed and validated to measure the collimated transmission precisely.
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Affiliation(s)
- Martin Hohmann
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Benjamin Lengenfelder
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Daniel Muhr
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
| | - Moritz Späth
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Maximilian Hauptkorn
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
| | - Florian Klämpfl
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
| | - Michael Schmidt
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordan-Straße 6, 91052 Erlangen, Germany
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Abdlaty R, Hayward J, Farrell T, Fang Q. Skin erythema and pigmentation: a review of optical assessment techniques. Photodiagnosis Photodyn Ther 2020; 33:102127. [PMID: 33276114 DOI: 10.1016/j.pdpdt.2020.102127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/28/2020] [Accepted: 11/23/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Skin erythema may present due to many causes. One of the common causes is prolonged exposure to sun rays. Other than sun exposure, skin erythema is an accompanying sign of dermatological diseases such as acne, psoriasis, melasma, post inflammatory hyperpigmentation, fever, as well as exposure to specific electromagnetic wave bands. METHODS Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Therefore, quantitative assessment of skin erythema was the target of several studies. The clinical standard for erythema evaluation is visual assessment. However, the former standard has some imperfections. For instance, it is subjective, and unqualified for precise color information exchange. To overcome these shortcomings, the past three decades witnessed various methodologies that aimed to achieve erythema objective assessment, such as diffuse reflectance spectroscopy (DRS), and both optical and non-optical systems. DISCUSSION This review article reports on the studies published in the past three decades where the performance, the mathematical tactics for computation, and the capabilities of erythema assessment techniques for cutaneous diseases are discussed. In particular, the achievements and limitations of the current techniques in erythema assessment are presented. CONCLUSION The profits and development trends of optical and non-optical methods are displayed to provide the researcher with awareness into the present technological advances and its potential for dermatological diseases research.
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Affiliation(s)
| | - Joseph Hayward
- Juravinski Cancer Centre, Hamilton Health Sciences, Ontario, Canada
| | - Thomas Farrell
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Ontario, Canada
| | - Qiyin Fang
- Engineering Physics, McMaster University, Ontario, Canada
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Fredriksson I, Larsson M, Strömberg T. Machine learning for direct oxygen saturation and hemoglobin concentration assessment using diffuse reflectance spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200177SSR. [PMID: 33205635 PMCID: PMC7670094 DOI: 10.1117/1.jbo.25.11.112905] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/28/2020] [Indexed: 05/13/2023]
Abstract
SIGNIFICANCE Diffuse reflectance spectroscopy (DRS) is frequently used to assess oxygen saturation and hemoglobin concentration in living tissue. Methods solving the inverse problem may include time-consuming nonlinear optimization or artificial neural networks (ANN) determining the absorption coefficient one wavelength at a time. AIM To present an ANN-based method that directly outputs the oxygen saturation and the hemoglobin concentration using the shape of the measured spectra as input. APPROACH A probe-based DRS setup with dual source-detector separations in the visible wavelength range was used. ANNs were trained on spectra generated from a three-layer tissue model with oxygen saturation and hemoglobin concentration as target. RESULTS Modeled evaluation data with realistic measurement noise showed an absolute root-mean-square (RMS) deviation of 5.1% units for oxygen saturation estimation. The relative RMS deviation for hemoglobin concentration was 13%. This accuracy is at least twice as good as our previous nonlinear optimization method. On blood-intralipid phantoms, the RMS deviation from the oxygen saturation derived from partial oxygen pressure measurements was 5.3% and 1.6% in two separate measurement series. Results during brachial occlusion showed expected patterns. CONCLUSIONS The presented method, directly assessing oxygen saturation and hemoglobin concentration, is fast, accurate, and robust to noise.
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Affiliation(s)
- Ingemar Fredriksson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
- Perimed AB, Stockholm, Sweden
- Address all correspondence to Ingemar Fredriksson,
| | - Marcus Larsson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Tomas Strömberg
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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15
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Nishidate I, Minakawa M, McDuff D, Wares MDA, Nakano K, Haneishi H, Aizu Y, Niizeki K. Simple and affordable imaging of multiple physiological parameters with RGB camera-based diffuse reflectance spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:1073-1091. [PMID: 32133238 PMCID: PMC7041446 DOI: 10.1364/boe.382270] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/15/2020] [Accepted: 01/15/2020] [Indexed: 05/11/2023]
Abstract
We propose a simple and affordable imaging technique to evaluate transcutaneously multiple physiological parameters by using a digital red-green-blue camera. In this method, the RGB-values were converted into tristimulus values in the CIE (Commission Internationale de l'Eclairage) XYZ color space, which is compatible with the common color spaces. Monte Carlo simulation for light transport in biological tissue was then performed to specify the relationship among the XYZ-values and the concentrations of oxygenated hemoglobin, deoxygenated hemoglobin, bilirubin, and melanin. The concentration of total hemoglobin and tissue oxygen saturation were also calculated from the estimated concentrations of oxygenated and deoxygenated hemoglobin. In vivo experiments with bile duct ligation in rats demonstrated that the estimated bilirubin concentration increased after ligation of the bile duct and reached around 22 mg/dl at 116 h after the onset of ligation, which corresponds to the ground truth value of bilirubin measured by a commercially available transcutaneous bilirubinometer. Experiments with rats while varying the fraction of inspired oxygen demonstrated that oxygenated hemoglobin and deoxygenated hemoglobin decreased and increased, respectively, as the fraction of inspired oxygen decreased. Consequently, tissue oxygen saturation dramatically decreased. We further extended the method to a non-contact imaging photo-plethysmograph and estimation of the percutaneous oxygen saturation. An empirical formula to estimate percutaneous oxygen saturation was derived from the pulse wave amplitudes of oxygenated and deoxygenated hemoglobin. The estimated percutaneous oxygen saturation dropped remarkably when a faction of inspired oxygen was below 19%, indicating the onset of hypoxemia due to hypoxia, whereas the tissue oxygen saturation decreased gradually according to the reduction of the faction of inspired oxygen. The results in this study indicate the potential of this method for imaging of multiple physiological parameters in skin tissue and evaluating an optical biomedical imaging technique that enables cost-effective, easy-to-use, portable, remotely administered, and/or point-of-care solutions.
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Affiliation(s)
- Izumi Nishidate
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications & Systems Engineering, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Masashi Minakawa
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications & Systems Engineering, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Daniel McDuff
- Microsoft Research, 4820 NE 36th Street, Building 99, Redmond, Washington 98052, USA
| | - MD. Abdul Wares
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Applications & Systems Engineering, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
- Government of Bangladesh, Ministry of Fisheries and Livestock, Department of Livestock Services, Khamar Bari Road, Farmgate, Dhaka, 1209, Bangladesh
| | - Kazuya Nakano
- Chiba University, Center for Frontier Medical Engineering, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Hideaki Haneishi
- Chiba University, Center for Frontier Medical Engineering, 1-33, Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Yoshihisa Aizu
- Muroran Institute of Technology, College of Design and Manufacturing Technology, 27-1 Mizumoto-cho, Muroran, Hokkaido, 050-8585, Japan
| | - Kyuichi Niizeki
- Yamagata University, Graduate School of Bio-System Engineering, Jonan, Yonezawa-shi, Yamagata, 992-8510, Japan
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LaRiviere B, Ferguson NL, Garman KS, Fisher DA, Jokerst NM. Methods of extraction of optical properties from diffuse reflectance measurements of ex-vivo human colon tissue using thin film silicon photodetector arrays. BIOMEDICAL OPTICS EXPRESS 2019; 10:5703-5715. [PMID: 31799041 PMCID: PMC6865100 DOI: 10.1364/boe.10.005703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/23/2019] [Accepted: 09/23/2019] [Indexed: 05/03/2023]
Abstract
Spatially resolved diffuse reflectance spectroscopy (SRDRS) is a promising technique for characterization of colon tissue. Herein, two methods for extracting the reduced scattering and absorption coefficients ( μ s ' ( λ ) and μ a ( λ ) ) from SRDRS data using lookup tables of simulated diffuse reflectance are reported. Experimental measurements of liquid tissue phantoms performed with a custom multi-pixel silicon SRDRS sensor spanning the 450 - 750 nm wavelength range were used to evaluate the extraction methods, demonstrating that the combined use of spatial and spectral data reduces extraction error compared to use of spectral data alone. Additionally, SRDRS measurements of normal and tumor ex-vivo human colon tissue are presented along with μ s ' ( λ ) and μ a ( λ ) extracted from these measurements.
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Affiliation(s)
- Ben LaRiviere
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
| | | | | | | | - Nan M. Jokerst
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA
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17
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Sweer JA, Chen T, Salimian K, Battafarano RJ, Durr NJ. Wide-field optical property mapping and structured light imaging of the esophagus with spatial frequency domain imaging. JOURNAL OF BIOPHOTONICS 2019; 12:e201900005. [PMID: 31056845 PMCID: PMC6721984 DOI: 10.1002/jbio.201900005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/31/2019] [Accepted: 05/02/2019] [Indexed: 05/18/2023]
Abstract
As the incidence of esophageal adenocarcinoma continues to rise, there is a need for improved imaging technologies with contrast to abnormal esophageal tissues. To inform the design of optical technologies that meet this need, we characterize the spatial distribution of the scattering and absorption properties from 471 to 851 nm of eight resected human esophagi tissues using Spatial Frequency Domain Imaging. Histopathology was used to categorize tissue types, including normal, inflammation, fibrotic, ulceration, Barrett's Esophagus and squamous cell carcinoma. Average absorption and reduced scattering coefficients of normal tissues were 0.211 ± 0.051 and 1.20 ± 0.18 mm-1 , respectively at 471 nm, and both values decreased monotonically with increasing wavelength. Fibrotic tissue exhibited at least 68% larger scattering signal across all wavelengths, while squamous cell carcinoma exhibited a 36% decrease in scattering at 471 nm. We additionally image the esophagus with high spatial frequencies up to 0.5 mm-1 and show strong reflectance contrast to tissue treated with radiation. Lastly, we observe that esophageal absorption and scattering values change by an average of 9.4% and 2.7% respectively over a 30 minute duration post-resection. These results may guide system design for the diagnosis, prevention and monitoring of esophageal pathologies.
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Affiliation(s)
- Jordan A. Sweer
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Tianyi Chen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Kevan Salimian
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Richard J. Battafarano
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nicholas J. Durr
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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18
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Yariv I, Duadi H, Chakraborty R, Fixler D. Algorithm for in vivo detection of tissue type from multiple scattering light phase images. BIOMEDICAL OPTICS EXPRESS 2019; 10:2909-2917. [PMID: 31259061 PMCID: PMC6583353 DOI: 10.1364/boe.10.002909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 05/30/2023]
Abstract
In vivo physiological assessments are typically done by either imaging techniques or by sensing changes in the attenuation coefficient. Using visible or near-infrared (NIR), imaging is mainly possible for thin tissues. On the other hand, clinical information can also be detected by examining changes in tissue optical properties. The most challenging aspect in sensing techniques is the spectral dependent scattering, which varies with the physiological state and tissue type. We have previously published our novel noninvasive nanophotonics technique for detecting tissue scattering based on reflectance measurements: the iterative multi-plane optical property extraction (IMOPE). The IMOPE reconstructs the reemitted light phase using an iterative algorithm and extracts the scattering properties based on a theoretical model. This paper presents the in vivo application of distinguishing between different mouse tissue areas. The reconstructed phase images reveal different areas in the inner thigh of a mouse, which are related to the muscle, bone, and skin. The IMOPE uses the reconstructed phases for sensing and detecting unseen components beneath the skin surface. This technique could be further applied to the diagnosis of various physiological states.
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19
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Yariv I, Duadi H, Fixler D. Optical method to extract the reduced scattering coefficient from tissue: theory and experiments. OPTICS LETTERS 2018; 43:5299-5302. [PMID: 30382992 DOI: 10.1364/ol.43.005299] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/24/2018] [Indexed: 06/08/2023]
Abstract
Tissues are considered challenging in terms of structure and composition analysis due to their tendency to multiple scatter the incident light. One of the most common theories for extracting optical properties of tissue is diffusion reflection (DR). In this Letter, we propose a new paradigm for estimating the reduced scattering coefficient of a medium from the reflected light phase. The technique is a modified DR theory wherein the phase is calculated by the product of the wavenumber and the average pathlength. This theory is supported by the reconstructed phase of tissue-like phantom experiments from an iterative algorithm.
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20
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Balthasar AJR, Bydlon TM, Ippel H, van der Voort M, Hendriks BHW, Lucassen GW, van Geffen GJ, van Kleef M, van Dijk P, Lataster A. Optical signature of nerve tissue-Exploratory ex vivo study comparing optical, histological, and molecular characteristics of different adipose and nerve tissues. Lasers Surg Med 2018; 50:948-960. [PMID: 29756651 PMCID: PMC6220981 DOI: 10.1002/lsm.22938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2018] [Indexed: 02/02/2023]
Abstract
Background During several anesthesiological procedures, needles are inserted through the skin of a patient to target nerves. In most cases, the needle traverses several tissues—skin, subcutaneous adipose tissue, muscles, nerves, and blood vessels—to reach the target nerve. A clear identification of the target nerve can improve the success of the nerve block and reduce the rate of complications. This may be accomplished with diffuse reflectance spectroscopy (DRS) which can provide a quantitative measure of the tissue composition. The goal of the current study was to further explore the morphological, biological, chemical, and optical characteristics of the tissues encountered during needle insertion to improve future DRS classification algorithms. Methods To compare characteristics of nerve tissue (sciatic nerve) and adipose tissues, the following techniques were used: histology, DRS, absorption spectrophotometry, high‐resolution magic‐angle spinning nuclear magnetic resonance (HR‐MAS NMR) spectroscopy, and solution 2D 13C‐1H heteronuclear single‐quantum coherence spectroscopy. Tissues from five human freshly frozen cadavers were examined. Results Histology clearly highlights a higher density of cellular nuclei, collagen, and cytoplasm in fascicular nerve tissue (IFAS). IFAS showed lower absorption of light around 1200 nm and 1750 nm, higher absorption around 1500 nm and 2000 nm, and a shift in the peak observed around 1000 nm. DRS measurements showed a higher water percentage and collagen concentration in IFAS and a lower fat percentage compared to all other tissues. The scattering parameter (b) was highest in IFAS. The HR‐MAS NMR data showed three extra chemical peak shifts in IFAS tissue. Conclusion Collagen, water, and cellular nuclei concentration are clearly different between nerve fascicular tissue and other adipose tissue and explain some of the differences observed in the optical absorption, DRS, and HR‐NMR spectra of these tissues. Some differences observed between fascicular nerve tissue and adipose tissues cannot yet be explained but may be helpful in improving the discriminatory capabilities of DRS in anesthesiology procedures. Lasers Surg. Med. 50:948–960, 2018. © 2018 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Andrea J R Balthasar
- Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Hans Ippel
- Department of Biochemistry, Faculty of Health Medicine and Life Science, Maastricht University, Maastricht, The Netherlands
| | | | - Benno H W Hendriks
- Philips Research, Eindhoven, The Netherlands.,Delft University of Technology, Department of BioMechanical Engineering, Delft, The Netherlands
| | | | - Geert-Jan van Geffen
- Department of Anesthesiology, University Medical Center St. Radboud, Nijmegen, The Netherlands
| | - Maarten van Kleef
- Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Paul van Dijk
- Department of Anatomy and Embryology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Arno Lataster
- Department of Anatomy and Embryology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
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Martinez AF, McCachren SS, Lee M, Murphy HA, Zhu C, Crouch BT, Martin HL, Erkanli A, Rajaram N, Ashcraft KA, Fontanella AN, Dewhirst MW, Ramanujam N. Metaboloptics: Visualization of the tumor functional landscape via metabolic and vascular imaging. Sci Rep 2018. [PMID: 29520098 PMCID: PMC5843602 DOI: 10.1038/s41598-018-22480-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Many cancers adeptly modulate metabolism to thrive in fluctuating oxygen conditions; however, current tools fail to image metabolic and vascular endpoints at spatial resolutions needed to visualize these adaptations in vivo. We demonstrate a high-resolution intravital microscopy technique to quantify glucose uptake, mitochondrial membrane potential (MMP), and SO2 to characterize the in vivo phentoypes of three distinct murine breast cancer lines. Tetramethyl rhodamine, ethyl ester (TMRE) was thoroughly validated to report on MMP in normal and tumor-bearing mice. Imaging MMP or glucose uptake together with vascular endpoints revealed that metastatic 4T1 tumors maintained increased glucose uptake across all SO2 (“Warburg effect”), and also showed increased MMP relative to normal tissue. Non-metastatic 67NR and 4T07 tumor lines both displayed increased MMP, but comparable glucose uptake, relative to normal tissue. The 4T1 peritumoral areas also showed a significant glycolytic shift relative to the tumor regions. During a hypoxic stress test, 4T1 tumors showed significant increases in MMP with corresponding significant drops in SO2, indicative of intensified mitochondrial metabolism. Conversely, 4T07 and 67NR tumors shifted toward glycolysis during hypoxia. Our findings underscore the importance of imaging metabolic endpoints within the context of a living microenvironment to gain insight into a tumor’s adaptive behavior.
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Affiliation(s)
- Amy F Martinez
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
| | | | - Marianne Lee
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Helen A Murphy
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Brian T Crouch
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Hannah L Martin
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Alaattin Erkanli
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC, USA
| | | | | | | | | | - Nirmala Ramanujam
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
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22
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In Vivo Evaluation of Cerebral Hemodynamics and Tissue Morphology in Rats during Changing Fraction of Inspired Oxygen Based on Spectrocolorimetric Imaging Technique. Int J Mol Sci 2018; 19:ijms19020491. [PMID: 29415505 PMCID: PMC5855713 DOI: 10.3390/ijms19020491] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/30/2017] [Accepted: 01/22/2018] [Indexed: 11/24/2022] Open
Abstract
During surgical treatment for cerebrovascular diseases, cortical hemodynamics are often controlled by bypass graft surgery, temporary occlusion of arteries, and surgical removal of veins. Since the brain is vulnerable to hypoxemia and ischemia, interruption of cerebral blood flow reduces the oxygen supply to tissues and induces irreversible damage to cells and tissues. Monitoring of cerebral hemodynamics and alteration of cellular structure during neurosurgery is thus crucial. Sequential recordings of red-green-blue (RGB) images of in vivo exposed rat brains were made during hyperoxia, normoxia, hypoxia, and anoxia. Monte Carlo simulation of light transport in brain tissue was used to specify relationships among RGB-values and oxygenated hemoglobin concentration (CHbO), deoxygenated hemoglobin concentration (CHbR), total hemoglobin concentration (CHbT), hemoglobin oxygen saturation (StO2), and scattering power b. Temporal courses of CHbO, CHbR, CHbT, and StO2 indicated physiological responses to reduced oxygen delivery to cerebral tissue. A rapid decrease in light scattering power b was observed after respiratory arrest, similar to the negative deflection of the extracellular direct current (DC) potential in so-called anoxic depolarization. These results suggest the potential of this method for evaluating pathophysiological conditions and loss of tissue viability.
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Jelvehgaran P, Alderliesten T, Weda JJA, de Bruin M, Faber DJ, Hulshof MCCM, van Leeuwen TG, van Herk M, de Boer JF. Visibility of fiducial markers used for image-guided radiation therapy on optical coherence tomography for registration with CT: An esophageal phantom study. Med Phys 2017; 44:6570-6582. [DOI: 10.1002/mp.12624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/14/2017] [Accepted: 10/03/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Pouya Jelvehgaran
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
- Department of Radiation Oncology; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
- Institute for Laser Life and Biophotonics Amsterdam; Physics and Astronomy; VU University Amsterdam; Amsterdam HV 1081 The Netherlands
| | - Tanja Alderliesten
- Department of Radiation Oncology; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
| | - Jelmer J. A. Weda
- Institute for Laser Life and Biophotonics Amsterdam; Physics and Astronomy; VU University Amsterdam; Amsterdam HV 1081 The Netherlands
| | - Martijn de Bruin
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
- Department of Urology; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
| | - Dirk J. Faber
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
| | - Maarten C. C. M. Hulshof
- Department of Radiation Oncology; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
| | - Ton G. van Leeuwen
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
| | - Marcel van Herk
- Department of Biomedical Engineering and Physics; Academic Medical Center; University of Amsterdam; Amsterdam AZ 1105 The Netherlands
- Institute of Cancer Sciences; University of Manchester; Manchester UK
| | - Johannes F. de Boer
- Institute for Laser Life and Biophotonics Amsterdam; Physics and Astronomy; VU University Amsterdam; Amsterdam HV 1081 The Netherlands
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Liu L, Wan W, Qin Z, Zhang L, Jiang J, Wang Y, Gao F, Zhao H. Determination of optical properties of turbid medium from relative interstitial CW radiance measurements using the incomplete P3 approximation. OPTICS EXPRESS 2017; 25:25295-25309. [PMID: 29041198 DOI: 10.1364/oe.25.025295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Interstitial determination of the tissue optical properties is important in biomedicine, especially for interstitial laser therapies. Continuous wave (CW) radiance techniques which examine light from multiple directions have been proposed as minimally invasive methods for determining the optical properties under an interstitial probe arrangement. However, both the fitting algorithm based on the P3 approximation and the analytical method based on the diffusion approximation (DA), which are currently used recovery algorithms, cannot extract the optical properties of tissue with low transport albedos accurately from radiance measurements. In this paper, we proposed an incomplete P3 approximation for the radiance, the P3in for short, which is the asymptotic part of the solution for the P3 approximation. The relative differences between the P3in and the P3 were within 0.48% over a wide range of clinically relevant optical properties for measurements at source detector separations (SDS) from 5 mm to 10 mm and angles from 0° to 160°. Based on the P3in, we developed an analytical method for extracting the optical properties directly using simple expressions constructed from the radiance measurements at only two SDSs and four angles. The developed recovery algorithm was verified by simulated and experimental radiance data. The results show that both the absorption and reduced scattering coefficients were recovered accurately with relative errors within 5.28% and 3.86%, respectively, from the simulated data and with relative errors within 10.82% and 10.67%, respectively, from the experimental data over a wide range of albedos from 0.5 to 0.99. Since the developed P3in-based radiance technique can obtain the optical properties rapidly from the measurements at only two SDSs and four angles, it is expected to be used for in vivo and in situ determination of the optical properties in online treatment planning during laser therapies.
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Piazena H, Meffert H, Uebelhack R. Spectral Remittance and Transmittance of Visible and Infrared-A Radiation in Human Skin-Comparison Betweenin vivoMeasurements and Model Calculations. Photochem Photobiol 2017; 93:1449-1461. [DOI: 10.1111/php.12785] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 04/04/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Helmut Piazena
- Medical Photobiology Group; Charité - University Medicine Berlin; Berlin Germany
| | | | - Ralf Uebelhack
- Medical Photobiology Group; Charité - University Medicine Berlin; Berlin Germany
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26
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Lim L, Mastragostino R, Ng K, Zheng G, Wilson BC. Can photoacoustic imaging quantify surface-localized J-aggregating nanoparticles? JOURNAL OF BIOMEDICAL OPTICS 2017; 22:76008. [PMID: 28703256 DOI: 10.1117/1.jbo.22.7.076008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 06/21/2017] [Indexed: 05/07/2023]
Abstract
We investigate the feasibility of photoacoustic (PA) imaging to quantify the concentration of surface-localized nanoparticles, using tissue-mimicking phantoms and imaging with a commercial PA instrument at 815 nm and a linear-array transducer at a center frequency of 40 MHz. The nanoparticles were J-aggregating porphysomes (JNP) comprising self-assembling, all-organic porphyrin-lipid micelles with a molar absorption coefficient of 8.7×108 cm−1 M−1 at this wavelength. The PA signal intensity versus JNP areal concentration followed a sigmoidal curve with a reproducible linear range of ∼17 fmol/mm2 to 11 pmol/mm2, i.e., ∼3 orders of magnitude with ±34% error. For physiologically-relevant conditions (i.e., optical scattering-dominated tissues: transport albedo >0.8) and JNP concentrations above ∼330 fmol/mm2, the PA signal depends only on the nanoparticle concentration. Otherwise, independent measurement of the optical absorption and scattering properties of the underlying tissue is required for accurate quantification. The implications for surface PA imaging, such as in the use of targeted nanoparticles applied topically to tissue as in endoscopic diagnosis, are considered.
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Affiliation(s)
- Liang Lim
- University Health Network, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Robert Mastragostino
- University Health Network, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Kenneth Ng
- University of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada
| | - Gang Zheng
- University Health Network, Princess Margaret Cancer Centre, Toronto, Ontario, CanadabUniversity of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada
| | - Brian C Wilson
- University Health Network, Princess Margaret Cancer Centre, Toronto, Ontario, CanadabUniversity of Toronto, Department of Medical Biophysics, Toronto, Ontario, Canada
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Stringasci MD, Fortunato TC, Moriyama LT, Filho JDV, Bagnato VS, Kurachi C. Interstitial PDT using diffuser fiber-investigation in phantom and in vivo models. Lasers Med Sci 2017; 32:1009-1016. [PMID: 28474212 DOI: 10.1007/s10103-017-2225-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 04/27/2017] [Indexed: 11/30/2022]
Abstract
Photodynamic therapy (PDT) has been used for local treatment of several types of tumors. Light penetration of biological tissue is one limiting factor in PDT, decreasing the success rates of the treatment of invasive and solid tumors. In those cases, a possible solution is to use interstitial PDT, in which both diffuser optical fibers are inserted into the tumor. The uniformity of the diffuser emission plays a crucial role in planning the delivery of the appropriate light fluence and in ensuring treatment success. In this study, we characterized a diffuser optical fiber concerning its homogeneity. We showed that the diffuser emission can be inhomogeneous and that the necrosis generated by interstitial PDT using such a diffuser for illumination is asymmetrical in volume as a result. This observation has relevant consequences in achieving success in PDT and phototherapies in general, as the delivered light fluence depends on adequate previous knowledge of the irradiation profile.
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Affiliation(s)
- Mirian D Stringasci
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil.
| | - Thereza C Fortunato
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Lilian T Moriyama
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - José Dirceu Vollet Filho
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Vanderlei S Bagnato
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
| | - Cristina Kurachi
- Sao Carlos Institute of Physics, University of São Paulo, Trabalhador Sao-Carlense Street, Number 400, São Carlos, São Paulo, CEP: 13566-590, Brazil
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Nishidate I, Ishizuka T, Mustari A, Yoshida K, Kawauchi S, Sato S, Sato M. Evaluation of Cerebral Hemodynamics and Tissue Morphology of In Vivo Rat Brain Using Spectral Diffuse Reflectance Imaging. APPLIED SPECTROSCOPY 2017; 71:866-878. [PMID: 27381353 DOI: 10.1177/0003702816657569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We investigated a quantitative imaging of reduced scattering coefficients μs'( λ) and the absorption coefficients μa( λ) of in vivo cortical tissues in the range from visible to near-infrared (NIR) wavelengths based on diffuse reflectance spectral imaging technique. In this method, diffuse reflectance images of in vivo cortical tissue are acquired at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm). A multiple regression analysis aided by the Monte Carlo simulation for the absorbance spectra is then utilized to estimate the optical coefficients of cortical tissue. This analysis calculates the concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin, the scattering amplitude a and the scattering power b. The spectrum of absorption coefficient is deduced from the estimated concentrations of oxygenated hemoglobin and deoxygenated hemoglobin. The spectrum of reduced scattering coefficient is determined by the estimated scattering amplitude and scattering power. The particle size distribution of microstructure is calculated from the estimated scattering power b for evaluating the morphological change in brain tissue quantitatively. Animal experiments with in vivo exposed brain of rats demonstrated that the responses of the absorption properties to hyperoxic and anoxic conditions are in agreement with the expected well-known cortical hemodynamics. The average particle size was significantly reduced immediately after the onset of anoxia and then it was changed into an increase, which implied the swelling and shrinkage of the cellular and subcellular structures induced by loss of tissue viability in brain tissue.
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Affiliation(s)
- Izumi Nishidate
- 1 Tokyo University of Agriculture & Technology, Graduate School of Bio-application & Systems Engineering, Koganei, Tokyo, Japan
| | - Tomohiro Ishizuka
- 1 Tokyo University of Agriculture & Technology, Graduate School of Bio-application & Systems Engineering, Koganei, Tokyo, Japan
| | - Afrina Mustari
- 1 Tokyo University of Agriculture & Technology, Graduate School of Bio-application & Systems Engineering, Koganei, Tokyo, Japan
| | - Keiichiro Yoshida
- 1 Tokyo University of Agriculture & Technology, Graduate School of Bio-application & Systems Engineering, Koganei, Tokyo, Japan
| | - Satoko Kawauchi
- 2 National Defense Medical College Research Institute, Division of Biomedical Information Sciences, Tokorozawa, Saitama, Japan
| | - Shunichi Sato
- 2 National Defense Medical College Research Institute, Division of Biomedical Information Sciences, Tokorozawa, Saitama, Japan
| | - Manabu Sato
- 3 Yamagata University, Graduate School of Science and Engineering, Yonezawa, Yamagata, Japan
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29
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Du Le VN, Provias J, Murty N, Patterson MS, Nie Z, Hayward JE, Farrell TJ, McMillan W, Zhang W, Fang Q. Dual-modality optical biopsy of glioblastomas multiforme with diffuse reflectance and fluorescence: ex vivo retrieval of optical properties. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:27002. [PMID: 28157245 DOI: 10.1117/1.jbo.22.2.027002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 01/12/2017] [Indexed: 05/23/2023]
Abstract
Glioma itself accounts for 80% of all malignant primary brain tumors, and glioblastoma multiforme (GBM) accounts for 55% of such tumors. Diffuse reflectance and fluorescence spectroscopy have the potential to discriminate healthy tissues from abnormal tissues and therefore are promising noninvasive methods for improving the accuracy of brain tissue resection. Optical properties were retrieved using an experimentally evaluated inverse solution. On average, the scattering coefficient is 2.4 times higher in GBM than in low grade glioma (LGG), and the absorption coefficient is 48% higher. In addition, the ratio of fluorescence to diffuse reflectance at the emission peak of 460 nm is 2.6 times higher for LGG while reflectance at 650 nm is 2.7 times higher for GBM. The results reported also show that the combination of diffuse reflectance and fluorescence spectroscopy could achieve sensitivity of 100% and specificity of 90% in discriminating GBM from LGG during ex vivo measurements of 22 sites from seven glioma specimens. Therefore, the current technique might be a promising tool for aiding neurosurgeons in determining the extent of surgical resection of glioma and, thus, improving intraoperative tumor identification for guiding surgical intervention.
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Affiliation(s)
- Vinh Nguyen Du Le
- McMaster University, Radiation Sciences Graduate Program, Hamilton, Ontario, Canada
| | - John Provias
- McMaster University, Department of Anatomical Pathology, Hamilton, Ontario, Canada
| | - Naresh Murty
- McMaster University, Department of Surgery, Hamilton, Ontario, Canada
| | | | - Zhaojun Nie
- McMaster University, School of Biomedical Engineering, Hamilton, Ontario, Canada
| | - Joseph E Hayward
- Juravinski Cancer Centre, Hamilton, Ontario, CanadafMcMaster University, School of Interdisciplinary Science, Hamilton, Ontario, Canada
| | - Thomas J Farrell
- Juravinski Cancer Centre, Hamilton, Ontario, CanadafMcMaster University, School of Interdisciplinary Science, Hamilton, Ontario, Canada
| | - William McMillan
- Juravinski Cancer Centre, Hamilton, Ontario, CanadagMcMaster University, Department of Oncology, Hamilton, Ontario, Canada
| | - Wenbin Zhang
- Shanghai Jiaotong University Medical School, Shanghai 9th People's Hospital, Shanghai, China
| | - Qiyin Fang
- McMaster University, School of Biomedical Engineering, Hamilton, Ontario, CanadaiMcMaster University, Department of Engineering Physics, Hamilton, Ontario, Canada
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30
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Rohrbach DJ, Rigual N, Arshad H, Tracy EC, Cooper MT, Shafirstein G, Wilding G, Merzianu M, Baumann H, Henderson BW, Sunar U. Intraoperative optical assessment of photodynamic therapy response of superficial oral squamous cell carcinoma. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:18002. [PMID: 26780226 PMCID: PMC5996863 DOI: 10.1117/1.jbo.21.1.018002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/11/2015] [Indexed: 06/05/2023]
Abstract
This study investigated whether diffuse optical spectroscopy (DOS) measurements could assess clinical response to photodynamic therapy (PDT) in patients with head and neck squamous cell carcinoma (HNSCC). In addition, the correlation between parameters measured with DOS and the crosslinking of signal transducer and activator of transcription 3 (STAT3), a molecular marker for PDT-induced photoreaction, was investigated. Thirteen patients with early stage HNSCC received the photosensitizer 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and DOS measurements were performed before and after PDT in the operating room (OR). In addition, biopsies were acquired after PDT to assess the STAT3 crosslinking. Parameters measured with DOS, including blood volume fraction, blood oxygen saturation (StO2), HPPH concentration (cHPPH), HPPH fluorescence, and blood flow index (BFI), were compared to the pathologic response and the STAT3 crosslinking. The best individual predictor of pathological response was a change in cHPPH (sensitivity=60%, specificity=100%), while discrimination analysis using a two-parameter classifier (change in cHPPH and change in StO2) classified pathological response with 100% sensitivity and 100% specificity. BFI showed the best correlation with the crosslinking of STAT3. These results indicate that DOS-derived parameters can assess the clinical response in the OR, allowing for earlier reintervention if needed.
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Affiliation(s)
- Daniel J. Rohrbach
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
- Wright State University, Department of Biomedical, Industrial and Human Factors Engineering, 207 Russ Center, Dayton, Ohio 45435, United States
| | - Nestor Rigual
- Roswell Park Cancer Institute, Department of Head and Neck Surgery, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Hassan Arshad
- Roswell Park Cancer Institute, Department of Head and Neck Surgery, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Erin C. Tracy
- Roswell Park Cancer Institute, Department of Cellular and Molecular Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Michelle T. Cooper
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Gal Shafirstein
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Gregory Wilding
- Roswell Park Cancer Institute, Department of Biostatistics and Bioinformatics, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Mihai Merzianu
- Roswell Park Cancer Institute, Department of Pathology and Laboratory Medicine, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Heinz Baumann
- Roswell Park Cancer Institute, Department of Cellular and Molecular Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Barbara W. Henderson
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
| | - Ulas Sunar
- Roswell Park Cancer Institute, Department of Cell Stress Biology, Elm and Carlton Streets, Buffalo, New York 14263, United States
- Wright State University, Department of Biomedical, Industrial and Human Factors Engineering, 207 Russ Center, Dayton, Ohio 45435, United States
- State University of New York at Buffalo, Department of Biomedical Engineering, 332 Bonner Hall, Buffalo, New York 14228, United States
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31
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Radrich K, Ntziachristos V. Quantitative multi-spectral oxygen saturation measurements independent of tissue optical properties. JOURNAL OF BIOPHOTONICS 2016; 9:83-99. [PMID: 25765987 DOI: 10.1002/jbio.201400092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/19/2014] [Accepted: 01/26/2015] [Indexed: 06/04/2023]
Abstract
Imaging of tissue oxygenation is important in several applications associated with patient care. Optical sensing is commonly applied for assessing oxygen saturation but is often restricted to local measurements or else it requires spectral and spatial information at the expense of time. Many methods proposed so far require assumptions on the properties of measured tissue. In this study we investigated a computational method that uses only multispectral information and quantitatively computes tissue oxygen saturation independently of tissue optical properties. The method is based on linear transformations of measurements in three isosbestic points. We investigated the ideal isosbestic point combination out of six isosbestic points available for measurement in the visible and near-infrared region that enable accurate oxygen saturation computation. We demonstrate this method on controlled tissue mimicking phantoms having different optical properties and validated the measurements using a gas analyzer. A mean error of 2.9 ± 2.8% O2 Sat was achieved. Finally, we performed pilot studies in tissues in-vivo by measuring dynamic changes in fingers subjected to vascular occlusion, the vasculature of mouse ears and exposed mouse organs.
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Affiliation(s)
- Karin Radrich
- Technische Universität München, Chair for Biological Imaging, Munich, Germany
- Helmholtz Zentrum München, Institute for Biological and Medical Imaging, Neuherberg, Germany
| | - Vasilis Ntziachristos
- Technische Universität München, Chair for Biological Imaging, Munich, Germany
- Helmholtz Zentrum München, Institute for Biological and Medical Imaging, Neuherberg, Germany
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Gonzalez-Andrades M, Cardona JDLC, Ionescu AM, Mosse CA, Brown RA. Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method. PLoS One 2015; 10:e0142099. [PMID: 26566050 PMCID: PMC4643926 DOI: 10.1371/journal.pone.0142099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 10/16/2015] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Tissues and biomaterials used for corneal surface repair require fulfilling specific optical standards prior to implantation in the patient. However, there is not a feasible evaluation method to be applied in clinical or Good Manufacturing Practice settings. In this study, we describe and assess an innovative easy-applied photographic-based method (PBM) for measuring functional optical blurring and transparency in corneal surface grafts. METHODS Plastic compressed collagen scaffolds (PCCS) and multilayered amniotic membranes (AM) samples were optically and histologically evaluated. Transparency and image blurring measures were obtained by PBM, analyzing photographic images of a standardized band pattern taken through the samples. These measures were compared and correlated to those obtained applying the Inverse Adding-Doubling (IAD) technique, which is the gold standard method. RESULTS All the samples used for optical evaluation by PBM or IAD were histological suitable. PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD. The PBM indicated that PCCS had a transparency ratio (TR) value of 80.3 ± 2.8%, with a blurring index (BI) of 50.6 ± 4.2%. TR and BI obtained from the PBM showed a high correlation (ρ>|0.6|) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005). The AM optical properties showed that there was a largely linear relationship between the blurring and the number of amnion layers, with more layers producing greater blurring. CONCLUSIONS This innovative proposed method represents an easy-applied technique for evaluating transparency and blurriness of tissues and biomaterials used for corneal surface repair.
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Affiliation(s)
- Miguel Gonzalez-Andrades
- Tissue Repair & Engineering Centre, University College of London, London, United Kingdom
- Tissue Engineering Group, Department of Histology, University of Granada, Granada, Spain
- Ophthalmology Department, San Cecilio University Hospital, Granada, Spain
- * E-mail:
| | - Juan de la Cruz Cardona
- Laboratory of Biomaterials and Optics—Optics Department, University of Granada, Granada, Spain
| | - Ana Maria Ionescu
- Laboratory of Biomaterials and Optics—Optics Department, University of Granada, Granada, Spain
| | - Charles A. Mosse
- Optics Department, University College of London, London, United Kingdom
| | - Robert A. Brown
- Tissue Repair & Engineering Centre, University College of London, London, United Kingdom
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Vinckenbosch L, Lacaux C, Tindel S, Thomassin M, Obara T. Monte Carlo methods for light propagation in biological tissues. Math Biosci 2015; 269:48-60. [PMID: 26362232 DOI: 10.1016/j.mbs.2015.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 07/09/2015] [Accepted: 08/28/2015] [Indexed: 11/15/2022]
Affiliation(s)
- Laura Vinckenbosch
- Inria, BIGS, Villers-lès-Nancy, F-54600, France; Université de Fribourg, Département de Mathématiques, chemin du Musée 23, Fribourg CH-1700, Switzerland.
| | - Céline Lacaux
- Inria, BIGS, Villers-lès-Nancy, F-54600, France; Université de Lorraine, Institut Élie Cartan de Lorraine, UMR 7502, Vandœuvre-lès-Nancy, F-54506, France
| | - Samy Tindel
- Inria, BIGS, Villers-lès-Nancy, F-54600, France; Université de Lorraine, Institut Élie Cartan de Lorraine, UMR 7502, Vandœuvre-lès-Nancy, F-54506, France
| | - Magalie Thomassin
- Université de Lorraine, CRAN, UMR 7039, 9, avenue de la forêt de Haye, Vandœuvre-lès-Nancy, F-54516, France
| | - Tiphaine Obara
- Université de Lorraine, CRAN, UMR 7039, 9, avenue de la forêt de Haye, Vandœuvre-lès-Nancy, F-54516, France
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Naglič P, Pernuš F, Likar B, Bürmen M. Limitations of the commonly used simplified laterally uniform optical fiber probe-tissue interface in Monte Carlo simulations of diffuse reflectance. BIOMEDICAL OPTICS EXPRESS 2015; 6:3973-88. [PMID: 26504647 PMCID: PMC4605056 DOI: 10.1364/boe.6.003973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 05/20/2023]
Abstract
Light propagation models often simplify the interface between the optical fiber probe tip and tissue to a laterally uniform boundary with mismatched refractive indices. Such simplification neglects the precise optical properties of the commonly used probe tip materials, e.g. stainless steel or black epoxy. In this paper, we investigate the limitations of the laterally uniform probe-tissue interface in Monte Carlo simulations of diffuse reflectance. In comparison to a realistic probe-tissue interface that accounts for the layout and properties of the probe tip materials, the simplified laterally uniform interface is shown to introduce significant errors into the simulated diffuse reflectance.
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Affiliation(s)
- Peter Naglič
- Laboratory of Imaging Technologies, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Franjo Pernuš
- Laboratory of Imaging Technologies, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Boštjan Likar
- Laboratory of Imaging Technologies, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000 Ljubljana, Slovenia
- Sensum, Computer Vision Systems d.o.o., Tehnološki park 21, 1000 Ljubljana, Slovenia
| | - Miran Bürmen
- Laboratory of Imaging Technologies, Faculty of Electrical Engineering, University of Ljubljana, Tržaška cesta 25, 1000 Ljubljana, Slovenia
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Akter S, Maejima S, Kawauchi S, Sato S, Hinoki A, Aosasa S, Yamamoto J, Nishidate I. Evaluation of light scattering and absorption properties of in vivo rat liver using a single-reflectance fiber probe during preischemia, ischemia-reperfusion, and postmortem. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:076010. [PMID: 26214615 DOI: 10.1117/1.jbo.20.7.076010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 06/25/2015] [Indexed: 05/23/2023]
Abstract
Diffuse reflectance spectroscopy (DRS) has been extensively used for characterization of biological tissues as a noninvasive optical technique to evaluate the optical properties of tissue. We investigated a method for evaluating the reduced scattering coefficient μ(s)', the absorption coefficient μ(a), the tissue oxygen saturation StO₂, and the reduction of heme aa3 in cytochrome c oxidase CcO of in vivo liver tissue using a single-reflectance fiber probe with two source-collector geometries. We performed in vivo recordings of diffuse reflectance spectra for exposed rat liver during the ischemia-reperfusion induced by the hepatic portal (hepatic artery, portal vein, and bile duct) occlusion. The time courses of μ a at 500, 530, 570, and 584 nm indicated the hemodynamic change in liver tissue as well as StO₂. Significant increase in μ(a)(605)/μ(a)(620) during ischemia and after euthanasia induced by nitrogen breathing was observed, which indicates the reduction of heme aa3, representing a sign of mitochondrial energy failure. The time courses of μ(s)' at 500, 530, 570, and 584 nm were well correlated with those of μ(a), which also reflect the scattering by red blood cells. On the other hand, at 700 and 800 nm, a temporary increase in μ(s)' and an irreversible decrease in μ(s)' were observed during ischemia-reperfusion and after euthanasia induced by nitrogen breathing, respectively. The change in μ(s)' in the near-infrared wavelength region during ischemia is indicative of the morphological changes in the cellular and subcellular structures induced by the ischemia, whereas that after euthanasia implies the hepatocyte vacuolation. The results of the present study indicate the potential application of the current DRS system for evaluating the pathophysiological conditions of in vivo liver tissue.
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Affiliation(s)
- Sharmin Akter
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Application and Systems Engineering, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Satoshi Maejima
- National Defense Medical College, Department of Surgery, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Satoko Kawauchi
- National Defense Medical College Research Institute, Division of Biomedical Information Sciences, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Shunichi Sato
- National Defense Medical College Research Institute, Division of Biomedical Information Sciences, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Akinari Hinoki
- National Defense Medical College, Department of Surgery, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Suefumi Aosasa
- National Defense Medical College, Department of Surgery, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Junji Yamamoto
- National Defense Medical College, Department of Surgery, 3-2, Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Izumi Nishidate
- Tokyo University of Agriculture and Technology, Graduate School of Bio-Application and Systems Engineering, 2-24-16, Naka-cho, Koganei, Tokyo 184-8588, Japan
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36
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Saito T, Yamaguchi H. Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:126011. [PMID: 26720878 DOI: 10.1117/1.jbo.20.12.126011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/30/2015] [Indexed: 05/06/2023]
Abstract
Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO2) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values.
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37
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Honda N, Kariyama Y, Hazama H, Ishii T, Kitajima Y, Inoue K, Ishizuka M, Tanaka T, Awazu K. Optical properties of tumor tissues grown on the chorioallantoic membrane of chicken eggs: tumor model to assay of tumor response to photodynamic therapy. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:125001. [PMID: 26662299 DOI: 10.1117/1.jbo.20.12.125001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 11/05/2015] [Indexed: 05/21/2023]
Abstract
Herein, the optical adequacy of a tumor model prepared with tumor cells grown on the chorioallantoic membrane (CAM) of a chicken egg is evaluated as an alternative to the mouse tumor model to assess the optimal irradiation conditions in photodynamic therapy (PDT). The optical properties of CAM and mouse tumor tissues were measured with a double integrating sphere and the inverse Monte Carlo technique in the 350- to 1000-nm wavelength range. The hemoglobin and water absorption bands observed in the CAM tumor tissue (10 eggs and 10 tumors) are equal to that of the mouse tumor tissue (8 animals and 8 tumors). The optical intersubject variability of the CAM tumor tissues meets or exceeds that of the mouse tumor tissues, and the reduced scattering coefficient spectra of CAM tumor tissues can be equated with those of mouse tumor tissues. These results confirm that the CAM tumor model is a viable alternative to the mouse tumor model, especially for deriving optimal irradiation conditions in PDT.
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Affiliation(s)
- Norihiro Honda
- Osaka University, Institute for Academic Initiatives, 1-1 Yamadaoka, Suita, Osaka 565-0871, JapanbOsaka University, Graduate School of Engineering, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yoichiro Kariyama
- Osaka University, Graduate School of Engineering, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hisanao Hazama
- Osaka University, Graduate School of Engineering, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takuya Ishii
- SBI Pharmaceuticals Co., Ltd., Izumi Garden Tower 20F, 1-6-1, Roppongi, Minato-ku, Tokyo 106-6020, Japan
| | - Yuya Kitajima
- SBI Pharmaceuticals Co., Ltd., Izumi Garden Tower 20F, 1-6-1, Roppongi, Minato-ku, Tokyo 106-6020, Japan
| | - Katsushi Inoue
- SBI Pharmaceuticals Co., Ltd., Izumi Garden Tower 20F, 1-6-1, Roppongi, Minato-ku, Tokyo 106-6020, Japan
| | - Masahiro Ishizuka
- SBI Pharmaceuticals Co., Ltd., Izumi Garden Tower 20F, 1-6-1, Roppongi, Minato-ku, Tokyo 106-6020, Japan
| | - Tohru Tanaka
- SBI Pharmaceuticals Co., Ltd., Izumi Garden Tower 20F, 1-6-1, Roppongi, Minato-ku, Tokyo 106-6020, Japan
| | - Kunio Awazu
- Osaka University, Graduate School of Engineering, 2-1 Yamadaoka, Suita, Osaka 565-0871, JapandOsaka University, Graduate School of Frontier Biosciences, 1-3 Yamadaoka, Suita, Osaka 565-0871, JapaneOsaka University, The Global Center for Medical Engineerin
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Bregar M, Cugmas B, Naglic P, Hartmann D, Pernuš F, Likar B, Bürmen M. Properties of contact pressure induced by manually operated fiber-optic probes. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:127002. [PMID: 26720880 DOI: 10.1117/1.jbo.20.12.127002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/17/2015] [Indexed: 05/13/2023]
Abstract
We assess the properties of contact pressure applied by manually operated fiber-optic probes as a function of the operator, probe contact area, and sample stiffness. First, the mechanical properties of human skin sites with different skin structures, thicknesses, and underlying tissues were studied by in vivo indentation tests. According to the obtained results, three different homogeneous silicone skin phantoms were created to encompass the observed range of mechanical properties. The silicon phantoms were subsequently used to characterize the properties of the contact pressure by 10 experienced probe operators employing fiber-optic probes with different contact areas. A custom measurement system was used to collect the time-lapse of diffuse reflectance and applied contact pressure. The measurements were characterized by a set of features describing the transient and steady-state properties of the contact pressure and diffuse reflectance in terms of rise time, optical coupling, average value, and variability. The average applied contact pressure and contact pressure variability were found to significantly depend on the probe operator, probe contact area, and surprisingly also on the sample stiffness. Based on the presented results, we propose a set of practical guidelines for operators of manual probes.
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Affiliation(s)
- Maksimilijan Bregar
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Blaž Cugmas
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Peter Naglic
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Daniela Hartmann
- Ludwig-Maximilian University, Department of Dermatology and Allergology, Frauenlobstrasse 9-11, 80337 Munich, Germany
| | - Franjo Pernuš
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Boštjan Likar
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
| | - Miran Bürmen
- University of Ljubljana, Laboratory of Imaging Technologies, Faculty of Electrical Engineering, Tržaška cesta 25, 1000 Ljubljana, Slovenia
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Wall RA, Barton JK. Oblique incidence reflectometry: optical models and measurements using a side-viewing gradient index lens-based endoscopic imaging system. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:067002. [PMID: 24892970 PMCID: PMC4042830 DOI: 10.1117/1.jbo.19.6.067002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Revised: 04/07/2014] [Accepted: 05/01/2014] [Indexed: 05/08/2023]
Abstract
A side-viewing, 2.3-mm diameter oblique incidence reflectometry endoscope has been designed to obtain optical property measurements of turbid samples. Light from a single-mode fiber is relayed obliquely onto the tissue with a gradient index lens-based distal optics assembly and the resulting diffuse reflectance profile is imaged and collected with a 30,000 element, 0.72 mm clear aperture fiber bundle. Sampling the diffuse reflectance in two-dimensions allows for fitting of the reflected intensity profile to a well-known theoretical model, permitting the extraction of both absorption and reduced scattering coefficients of the tissue sample. Models and measurements of the endoscopic imaging system are presented in tissue phantoms and in vivo mouse colon, verifying the endoscope's capabilities to accurately measure effective attenuation coefficient and differentiate diseased from normal colon.
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Affiliation(s)
- R. Andrew Wall
- University of Arizona, College of Optical Sciences, 1630 E. University Boulevard, Tucson, Arizona 85721
| | - Jennifer K. Barton
- University of Arizona, College of Optical Sciences, 1630 E. University Boulevard, Tucson, Arizona 85721
- University of Arizona, Department of Biomedical Engineering, 1127 E. James E. Rogers Way, Tucson, Arizona 85721
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40
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Strömberg T, Karlsson H, Fredriksson I, Nyström FH, Larsson M. Microcirculation assessment using an individualized model for diffuse reflectance spectroscopy and conventional laser Doppler flowmetry. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:057002. [PMID: 24788373 DOI: 10.1117/1.jbo.19.5.057002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/07/2014] [Indexed: 06/03/2023]
Abstract
Microvascular assessment would benefit from co-registration of blood flow and hemoglobin oxygenation dynamics during stimulus response tests. We used a fiber-optic probe for simultaneous recording of white light diffuse reflectance (DRS; 475-850 nm) and laser Doppler flowmetry (LDF; 780 nm) spectra at two source-detector distances (0.4 and 1.2 mm). An inverse Monte Carlo algorithm, based on a multiparameter three-layer adaptive skin model, was used for analyzing DRS data. LDF spectra were conventionally processed for perfusion. The system was evaluated on volar forearm recordings of 33 healthy subjects during a 5-min systolic occlusion protocol. The calibration scheme and the optimal adaptive skin model fitted DRS spectra at both distances within 10%. During occlusion, perfusion decreased within 5 s while oxygenation decreased slowly (mean time constant 61 s; dissociation of oxygen from hemoglobin). After occlusion release, perfusion and oxygenation increased within 3 s (inflow of oxygenized blood). The increased perfusion was due to increased blood tissue fraction and speed. The supranormal hemoglobin oxygenation indicates a blood flow in excess of metabolic demands. In conclusion, by integrating DRS and LDF in a fiber-optic probe, a powerful tool for assessment of blood flow and oxygenation in the same microvascular bed has been presented.
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Affiliation(s)
- Tomas Strömberg
- Linköping University, University Hospital, Department of Biomedical Engineering, Linköping 581 85, Sweden
| | - Hanna Karlsson
- Linköping University, University Hospital, Department of Biomedical Engineering, Linköping 581 85, Sweden
| | - Ingemar Fredriksson
- Linköping University, University Hospital, Department of Biomedical Engineering, Linköping 581 85, SwedenbPerimed AB, Datavägen 9A, Järfälla 175 43, Sweden
| | - Fredrik H Nyström
- Linköping University, University Hospital, Department of Medical and Health Sciences, Linköping 581 85, Sweden
| | - Marcus Larsson
- Linköping University, University Hospital, Department of Biomedical Engineering, Linköping 581 85, Sweden
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41
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Grabtchak S, Montgomery LG, Whelan WM. Optical absorption and scattering properties of bulk porcine muscle phantoms from interstitial radiance measurements in 650-900 nm range. Phys Med Biol 2014; 59:2431-44. [PMID: 24743553 DOI: 10.1088/0031-9155/59/10/2431] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We demonstrated the application of relative radiance-based continuous wave (cw) measurements for recovering absorption and scattering properties (the effective attenuation coefficient, the diffusion coefficient, the absorption coefficient and the reduced scattering coefficient) of bulk porcine muscle phantoms in the 650-900 nm spectral range. Both the side-firing fiber (the detector) and the fiber with a spherical diffuser at the end (the source) were inserted interstitially at predetermined locations in the phantom. The porcine phantoms were prostate-shaped with ∼4 cm in diameter and ∼3 cm thickness and made from porcine loin or tenderloin muscles. The described method was previously validated using the diffusion approximation on simulated and experimental radiance data obtained for homogenous Intralipid-1% liquid phantom. The approach required performing measurements in two locations in the tissue with different distances to the source. Measurements were performed on 21 porcine phantoms. Spectral dependences of the effective attenuation and absorption coefficients for the loin phantom deviated from corresponding dependences for the tenderloin phantom for wavelengths <750 nm. The diffusion constant and the reduced scattering coefficient were very close for both phantom types. To quantify chromophore presence, the plot for the absorption coefficient was matched with a synthetic absorption spectrum constructed from deoxyhemoglobin, oxyhemoglobin and water. The closest match for the porcine loin spectrum was obtained with the following concentrations: 15.5 µM (±30% s.d.) Hb, 21 µM (±30% s.d.) HbO2 and 0.3 (±30% s.d.) fractional volume of water. The tenderloin absorption spectrum was best described by 30 µM Hb (±30% s.d), 19 µM (±30% s.d.) HbO2 and 0.3 (±30% s.d.) fractional volume of water. The higher concentration of Hb in tenderloin was consistent with a dark-red appearance of the tenderloin phantom. The method can be applied to a number of biological tissues and organs for interstitial optical interrogation.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada. Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, NS B3H3J5, Canada
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42
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Calabro KW, Bigio IJ. Influence of the phase function in generalized diffuse reflectance models: review of current formalisms and novel observations. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:75005. [PMID: 25027000 PMCID: PMC4161006 DOI: 10.1117/1.jbo.19.7.075005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/27/2014] [Accepted: 05/27/2014] [Indexed: 05/18/2023]
Abstract
Diffuse reflectance spectroscopy, which has been demonstrated as a noninvasive diagnostic technique, relies on quantitative models for extracting optical property values from turbid media, such as biological tissues. We review and compare reflectance models that have been published, and we test similar models over a much wider range of measurement parameters than previously published, with specific focus on the effects of the scattering phase function and the source-detector distance. It has previously been shown that the dependence of a forward reflectance model on the scattering phase function can be described more accurately using a variable, γ, which is a more predictive variable for reflectance than the traditional anisotropy factor, g. We show that variations in the reflectance model due to the phase function are strongly dependent on the source-detector separation, and we identify a dimensionless scattering distance at which reflectance is insensitive to the phase function. Further, we evaluate how variations in the phase function and source-detector separation affect the accuracy of inverse property extraction. By simultaneously fitting two or more reflectance spectra, measured at different source-detector separations, we also demonstrate that an estimate of γ can be extracted, in addition to the reduced scattering and absorption coefficients.
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Affiliation(s)
- Katherine W. Calabro
- Boston University, Department of Biomedical Engineering, 44 Cummington Street, Boston, Massachusetts 02215
- Synopsys Inc., 377 Simarano Drive, Marlborough, Massachusetts 01752
- Address all correspondence to: Katherine W. Calabro, E-mail:
| | - Irving J. Bigio
- Boston University, Department of Biomedical Engineering, 44 Cummington Street, Boston, Massachusetts 02215
- Boston University, Department of Electrical and Computer Engineering, 8 St. Mary’s Street, Boston, Massachusetts 02215
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43
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Grabtchak S, Callaghan KB, Whelan WM. Tagging photons with gold nanoparticles as localized absorbers in optical measurements in turbid media. BIOMEDICAL OPTICS EXPRESS 2013; 4:2989-3006. [PMID: 24409396 PMCID: PMC3862156 DOI: 10.1364/boe.4.002989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 06/03/2023]
Abstract
We analyze a role of a localized inclusion as a probe for spatial distributions of migrating photons in turbid media. We present new experimental data and two-dimensional analysis of radiance detection of a localized absorptive inclusion formed by gold nanoparticles in Intralipid-1% when the target is translated along the line connecting the light source and detector. Data are analyzed using the novel analytical expression for the relative angular photon distribution function for radiance developed by extending the perturbation approach for fluence. Obtained photon maps allow predicting conditions for detectability of inclusions for which proximity to the detector is essential.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, NS B3H3J5, Canada
| | - Kristen B. Callaghan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
| | - William M. Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Atlantic Veterinary College, Charlottetown, PEI C1A4P3, Canada
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44
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Baran TM, Fenn MC, Foster TH. Determination of optical properties by interstitial white light spectroscopy using a custom fiber optic probe. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:107007. [PMID: 24150093 PMCID: PMC3805060 DOI: 10.1117/1.jbo.18.10.107007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/24/2013] [Indexed: 05/05/2023]
Abstract
We demonstrate interstitial recovery of absorption and scattering coefficients using a custom optical probe and a Monte Carlo (MC)-based recovery algorithm. The probe consists of six side-firing spectroscopy fibers contained in a 1.1-mm outer diameter cladding, with each fiber having a different axial and angular position on the probe. Broadband white light is delivered by one of the fibers and is detected steady-state by the remaining fibers. These spatially and spectrally resolved data are analyzed using a MC-based fitting algorithm in order to extract the local optical properties. The technique was verified in tissue-simulating phantoms consisting of Intralipid-20% as a scatterer and either manganese meso-tetra (4-sulfanatophenyl) porphine or intact human erythrocytes as an absorber. Absorption coefficients were recovered with a mean error of 9% and scattering coefficients were recovered with a mean error of 19%, whereas the hemoglobin oxygen saturation was recovered with a mean error of 12%. These results demonstrate the feasibility of optical property recovery for situations in which surface-contact spectroscopy is not a possibility, and where only a single probe can be inserted into the tissue.
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Affiliation(s)
- Timothy M. Baran
- University of Rochester Medical Center, Department of Imaging Sciences, Rochester, New York 14642
- Address all correspondence to: Timothy M. Baran, University of Rochester Medical Center, Department of Imaging Sciences, 601 Elmwood Avenue, Box 648, Rochester, New York 14642. Tel: +(585) 276-3188; Fax: +(585) 273-1033; E-mail:
| | - Michael C. Fenn
- University of Rochester, Department of Physics & Astronomy, Rochester, New York 14627
| | - Thomas H. Foster
- University of Rochester Medical Center, Department of Imaging Sciences, Rochester, New York 14642
- University of Rochester, Department of Physics & Astronomy, Rochester, New York 14627
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45
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Bohndiek SE, Bodapati S, Van De Sompel D, Kothapalli SR, Gambhir SS. Development and application of stable phantoms for the evaluation of photoacoustic imaging instruments. PLoS One 2013; 8:e75533. [PMID: 24086557 PMCID: PMC3783368 DOI: 10.1371/journal.pone.0075533] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/15/2013] [Indexed: 11/23/2022] Open
Abstract
Photoacoustic imaging combines the high contrast of optical imaging with the spatial resolution and penetration depth of ultrasound. This technique holds tremendous potential for imaging in small animals and importantly, is clinically translatable. At present, there is no accepted standard physical phantom that can be used to provide routine quality control and performance evaluation of photoacoustic imaging instruments. With the growing popularity of the technique and the advent of several commercial small animal imaging systems, it is important to develop a strategy for assessment of such instruments. Here, we developed a protocol for fabrication of physical phantoms for photoacoustic imaging from polyvinyl chloride plastisol (PVCP). Using this material, we designed and constructed a range of phantoms by tuning the optical properties of the background matrix and embedding spherical absorbing targets of the same material at different depths. We created specific designs to enable: routine quality control; the testing of robustness of photoacoustic signals as a function of background; and the evaluation of the maximum imaging depth available. Furthermore, we demonstrated that we could, for the first time, evaluate two small animal photoacoustic imaging systems with distinctly different light delivery, ultrasound imaging geometries and center frequencies, using stable physical phantoms and directly compare the results from both systems.
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Affiliation(s)
- Sarah E. Bohndiek
- Bio-X Program and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sandhya Bodapati
- Bio-X Program and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California, United States of America
| | - Dominique Van De Sompel
- Bio-X Program and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sri-Rajasekhar Kothapalli
- Bio-X Program and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sanjiv S. Gambhir
- Bio-X Program and Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California, United States of America
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46
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Liao CC, Lo YL. Extraction of anisotropic parameters of turbid media using hybrid model comprising differential- and decomposition-based Mueller matrices. OPTICS EXPRESS 2013; 21:16831-16853. [PMID: 23938533 DOI: 10.1364/oe.21.016831] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A hybrid model comprising the differential Mueller matrix formalism and the Mueller matrix decomposition method is proposed for extracting the linear birefringence (LB), linear dichroism (LD), circular birefringence (CB), circular dichroism (CD), and depolarization properties (Dep) of turbid optical samples. In contrast to the differential-based Mueller matrix method, the proposed hybrid model provides full-range measurements of all the anisotropic properties of the optical sample. Furthermore, compared to the decomposition-based Mueller matrix method, the proposed model is insensitive to the multiplication order of the constituent basis matrices. The validity of the proposed method is confirmed by extracting the anisotropic properties of a compound chitosan-glucose-microsphere sample with LB/CB/Dep properties and two ferrofluidic samples with CB/CD/Dep and LB/LD/Dep properties, respectively. It is shown that the proposed hybrid model not only yields full-range measurements of all the anisotropic parameters, but is also more accurate and more stable than the decomposition method. Moreover, compared to the decomposition method, the proposed model more accurately reflects the dependency of the phase retardation angle and linear dichroism angle on the direction of the external magnetic field for ferrofluidic samples. Overall, the results presented in this study confirm that the proposed model has significant potential for extracting the optical parameters of real-world samples characterized by either single or multiple anisotropic properties.
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Affiliation(s)
- Chia-Chi Liao
- Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan
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47
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Estimation of melanin and hemoglobin using spectral reflectance images reconstructed from a digital RGB image by the Wiener estimation method. SENSORS 2013; 13:7902-15. [PMID: 23783740 PMCID: PMC3715247 DOI: 10.3390/s130607902] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/12/2013] [Accepted: 06/17/2013] [Indexed: 11/17/2022]
Abstract
A multi-spectral diffuse reflectance imaging method based on a single snap shot of Red-Green-Blue images acquired with the exposure time of 65 ms (15 fps) was investigated for estimating melanin concentration, blood concentration, and oxygen saturation in human skin tissue. The technique utilizes the Wiener estimation method to deduce spectral reflectance images instantaneously from an RGB image. Using the resultant absorbance spectrum as a response variable and the extinction coefficients of melanin, oxygenated hemoglobin and deoxygenated hemoglobin as predictor variables, multiple regression analysis provides regression coefficients. Concentrations of melanin and total blood are then determined from the regression coefficients using conversion vectors that are numerically deduced in advance by the Monte Carlo simulations for light transport in skin. Oxygen saturation is obtained directly from the regression coefficients. Experiments with a tissue-like agar gel phantom validated the method. In vivo experiments on fingers during upper limb occlusion demonstrated the ability of the method to evaluate physiological reactions of human skin.
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48
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Sunar U. Monitoring photodynamic therapy of head and neck malignancies with optical spectroscopies. World J Clin Cases 2013; 1:96-105. [PMID: 24303476 PMCID: PMC3845916 DOI: 10.12998/wjcc.v1.i3.96] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/02/2013] [Accepted: 05/08/2013] [Indexed: 02/05/2023] Open
Abstract
In recent years there has been significant developments in photosensitizers (PSs), light sources and light delivery systems that have allowed decreasing the treatment time and skin phototoxicity resulting in more frequent use of photodynamic therapy (PDT) in the clinical settings. Compared to standard treatment approaches such as chemo-radiation and surgery, PDT has much reduced morbidity for head and neck malignancies and is becoming an alternative treatment option. It can be used as an adjunct therapy to other treatment modalities without any additive cumulative side effects. Surface illumination can be an option for pre-malignant and early-stage malignancies while interstitial treatment is for debulking of thick tumors in the head and neck region. PDT can achieve equivalent or greater efficacy in treating head and neck malignancies, suggesting that it may be considered as a first line therapy in the future. Despite progressive development, clinical PDT needs improvement in several topics for wider acceptance including standardization of protocols that involve the same administrated light and PS doses and establishing quantitative tools for PDT dosimetry planning and response monitoring. Quantitative measures such as optical parameters, PS concentration, tissue oxygenation and blood flow are essential for accurate PDT dosimetry as well as PDT response monitoring and assessing therapy outcome. Unlike conventional imaging modalities like magnetic resonance imaging, novel optical imaging techniques can quantify PDT-related parameters without any contrast agent administration and enable real-time assessment during PDT for providing fast feedback to clinicians. Ongoing developments in optical imaging offer the promise of optimization of PDT protocols with improved outcomes.
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49
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Kano A, Rouse AR, Gmitro AF. Ultrathin single-channel fiberscopes for biomedical imaging. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:16013. [PMID: 23334688 PMCID: PMC3548518 DOI: 10.1117/1.jbo.18.1.016013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Ultrathin flexible fiberscopes typically have separate illumination and imaging channels and are available in diameters ranging from 0.5 to 2.5 mm. Diameters can potentially be reduced by combining the illumination and imaging paths into a single fiberoptic channel. Single-channel fiberscopes must incorporate a system to minimize Fresnel reflections from air-glass interfaces within the common illumination and detection path. The Fresnel reflection at the proximal surface of the fiber bundle is particularly problematic. This paper describes and compares methods to reduce the background signal from the proximal surface of the fiber bundle. Three techniques are evaluated: (1) antireflective (AR)-coating the proximal face of the fiber, (2) incorporating crossed polarizers into the light path, and (3) a novel technique called numerical aperture sharing, whereby a portion of the image numerical aperture is devoted to illumination and a portion to detection.
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Affiliation(s)
- Angelique Kano
- University of Arizona, College of Optical Sciences and Department of Medical Imaging, Tucson, Arizona
| | - Andrew R. Rouse
- University of Arizona, College of Optical Sciences and Department of Medical Imaging, Tucson, Arizona
| | - Arthur F. Gmitro
- University of Arizona, College of Optical Sciences and Department of Medical Imaging, Tucson, Arizona
- Address all correspondence to: Andrew R. Rouse, University of Arizona, College of Optical Sciences and Department of Medical Imaging, Tucson, Arizona. Tel: +520 626 4720; E-mail:
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50
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Grabtchak S, Whelan WM. Separation of absorption and scattering properties of turbid media using relative spectrally resolved cw radiance measurements. BIOMEDICAL OPTICS EXPRESS 2012; 3:2371-80. [PMID: 23082279 PMCID: PMC3469994 DOI: 10.1364/boe.3.002371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/27/2012] [Accepted: 08/27/2012] [Indexed: 05/10/2023]
Abstract
We present a new method for extracting the effective attenuation coefficient and the diffusion coefficient from relative spectrally resolved cw radiance measurements using the diffusion approximation. The method is validated on both simulated and experimental radiance data sets using Intralipid-1% as a test platform. The effective attenuation coefficient is determined from a simple algebraic expression constructed from a ratio of two radiance measurements at two different source-detector separations and the same 90° angle. The diffusion coefficient is determined from another ratio constructed from two radiance measurements at two angles (0° and 180°) and the same source-detector separation. The conditions of the validity of the method as well as possible practical applications are discussed.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Department of Electrical and Computer Engineering, Dalhousie University, Halifax, NS B3J1Z1, Canada
- Department of Physics, Dalhousie University, Halifax, NS B3H3J5, Canada
| | - William M. Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Atlantic Veterinary College, Charlottetown, PEI C1A4P3, Canada
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