1
|
Foroughimehr N, Vilagosh Z, Yavari A, Wood A. The Impact of Base Cell Size Setup on the Finite Difference Time Domain Computational Simulation of Human Cornea Exposed to Millimeter Wave Radiation at Frequencies above 30 GHz. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22155924. [PMID: 35957481 PMCID: PMC9371411 DOI: 10.3390/s22155924] [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: 07/15/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 05/10/2023]
Abstract
Mobile communication has achieved enormous technology innovations over many generations of progression. New cellular technology, including 5G cellular systems, is being deployed and making use of higher frequencies, including the Millimetre Wave (MMW) range (30-300 GHz) of the electromagnetic spectrum. Numerical computational techniques such as the Finite Difference Time Domain (FDTD) method have been used extensively as an effective approach for assessing electromagnetic fields' biological impacts. This study demonstrates the variation of the accuracy of the FDTD computational simulation system when different meshing sizes are used, by using the interaction of the critically sensitive human cornea with EM in the 30 to 100 GHz range. Different approaches of base cell size specifications were compared. The accuracy of the computation is determined by applying planar sensors showing the detail of electric field distribution as well as the absolute values of electric field collected by point sensors. It was found that manually defining the base cell sizes reduces the model size as well as the computation time. However, the accuracy of the computation decreases in an unpredictable way. The results indicated that using a cloud computing capacity plays a crucial role in minimizing the computation time.
Collapse
Affiliation(s)
- Negin Foroughimehr
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Correspondence:
| | - Zoltan Vilagosh
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| | - Ali Yavari
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| | - Andrew Wood
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| |
Collapse
|
2
|
Terahertz Imaging for Formalin Fixed Malignant Liver Tumors Using Two-Band Beamline at the Accelerator Facility of Nihon University. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the transmission characteristics of formalin fixed human liver samples in which normal liver tissue and malignant liver tumor were mixed using terahertz (THz) coherent synchrotron radiation at an infrared free-electron laser (FEL) facility at Nihon University. Infrared-FEL imaging has indicated that the amount of water molecules in the tumor tissue is not different from that in the normal tissue. However, the transmission of the incipient tumor tissue was lower than that of the normal tissue in THz imaging because the tumor tissue contained more water molecular clusters than the normal tissue. The tumor tissue became more permeable owing to the development of fibrous tissue around it. THz imaging will be more useful for discriminating liver tissues by increasing the spatial resolution.
Collapse
|
3
|
Ke L, Wu QYS, Zhang N, Yang Z, Teo EPW, Mehta JS, Liu YC. Terahertz spectroscopy analysis of human corneal sublayers. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210014SSRR. [PMID: 33899380 PMCID: PMC8071781 DOI: 10.1117/1.jbo.26.4.043011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
SIGNIFICANCE Corneal diseases is a major cause of reversible blindness in the world. Monitoring the progression of human corneal edema or corneal scarring to prevent the disease entering into the end stage is crucial. AIM We present a method for sensing human corneal composition at different depths, namely focused on the epithelium and stromal layer, using high-sensitivity terahertz (THz) broadband spectroscopy. APPROACH From the proposed methodology, the THz temporal and absorption spectra of human corneas at different edema stages have been studied. THz wave signals were collected from the direct reflection and four other collection points along the THz wave propagation direction as reviewed from the simulation THz electrical field. RESULT Our results show that the epithelium layer acts as a good barrier to maintain hydration level of the stroma, and the quality of the epithelium can be used to predict the level of corneal swelling in corneal edema. At the detection points near to the incident point, the THz frequency spectra demonstrated interference oscillation behavior. At the final edema observing time, results showed that the epithelium lose its barrier properties. The intactness of the epithelium can be used to predict the edema severity in the final stage. When the detection points are further away from the incident point, the THz spectra are believed to contain information from stromal layer. Stromal absorption spectra demonstrated correlation with optical coherence tomography thickness results. CONCLUSION The hydration concentration from stromal layer was further quantitatively calculated. At the end of the experiment, all the corneal hydration levels reach to the same value which shows that the edema hydration has reached maximum saturation. The information of individual sublayers of the cornea is obtained by characterizing noninvasively with the use of THz spectroscopy. To our knowledge, this is the first report of using THz for noninvasive characterization of sublayers of the cornea.
Collapse
Affiliation(s)
- Lin Ke
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore
| | - Qing Yang Steve Wu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore
| | - Nan Zhang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore
| | - Zaifeng Yang
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore
| | | | - Jodhbir S. Mehta
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
- Duke-NUS Medical School, Ophthalmology and Visual Science Academic Clinical Research Program, Singapore
| | - Yu-Chi Liu
- Singapore Eye Research Institute, Singapore
- Singapore National Eye Centre, Singapore
- Duke-NUS Medical School, Ophthalmology and Visual Science Academic Clinical Research Program, Singapore
| |
Collapse
|
4
|
Mizuno M, Kitahara H, Sasaki K, Tani M, Kojima M, Suzuki Y, Tasaki T, Tatematsu Y, Fukunari M, Wake K. Dielectric property measurements of corneal tissues for computational dosimetry of the eye in terahertz band in vivo and in vitro. BIOMEDICAL OPTICS EXPRESS 2021; 12:1295-1307. [PMID: 33796354 PMCID: PMC7984789 DOI: 10.1364/boe.412769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/16/2021] [Accepted: 01/27/2021] [Indexed: 05/08/2023]
Abstract
The dielectric constant of the normal corneal tissue of a rabbit eye was obtained in vitro in the range from approximately 0.1 to 1 THz, and the drying process on the eye surface exposed to high-power terahertz waves was investigated by in vivo reflectance measurement using terahertz time-domain spectroscopy. When the rabbit eye was exposed to terahertz waves at 162 GHz for 6 min with an irradiation power of 360 or 480 mW/cm2, the reflectance temporally increased and then decreased with a temperature increase. Based on multiple-reflection calculation using the dielectric constant and anterior segment optical coherence tomography images, those changes in reflectance were attributed to drying of the tear and epithelium of the cornea, respectively. Furthermore, the drying progressed over a temperature increase of around 5°C under our exposure conditions. These findings suggest that the possibility of eye damage increases with the progress of drying and that the setting of the eye surface conditions can be a cause of disagreement between computational and experimental data of absorbed energy under high-level irradiation because reflectance is related to terahertz wave penetration in the eye tissue. The time-domain spectroscopic measurements were useful for the acquisition of the dielectric constant as well as for the real-time monitoring of the eye conditions during exposure measurement.
Collapse
Affiliation(s)
- Maya Mizuno
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Hideaki Kitahara
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kensuke Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Masahiko Tani
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masami Kojima
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yukihisa Suzuki
- Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Takafumi Tasaki
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
- Department of Medical Zoology, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yoshinori Tatematsu
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masafumi Fukunari
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kanako Wake
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| |
Collapse
|
5
|
Liu YC, Ke L, Yang SWQ, Nan Z, Teo EPW, Lwin NC, Lin MTY, Lee IXY, Chan ASY, Schmetterer L, Mehta JS. Safety profiles of terahertz scanning in ophthalmology. Sci Rep 2021; 11:2448. [PMID: 33510290 PMCID: PMC7843699 DOI: 10.1038/s41598-021-82103-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 01/15/2021] [Indexed: 01/20/2023] Open
Abstract
Terahertz (THz) technology has emerged recently as a potential novel imaging modality in biomedical fields, including ophthalmology. However, the ocular biological responses after THz electromagnetic exposure have not been investigated. We conducted a rabbit study to evaluate the safety profiles of THz scanning on eyes, at a tissue, cellular, structural and functional level. Eight animals (16 eyes) were analysed after excessive THz exposure (control, 1 h, 4 h, and 1 week after continuous 4-h exposure; THz frequency = 0.3 THz with continuous pulse generated at 40 µW). We found that at all the time points, the corneas and lens remained clear with no corneal haze or lens opacity formation clinically and histopathologically. No thermal effect, assessed by thermographer, was observed. The rod and cone cell-mediated electroretinography responses were not significantly altered, and the corneal keratocytes activity as well as endothelial viability, assessed by in-vivo confocal microscopy, was not affected. Post-exposed corneas, lens and retinas exhibited no significant changes in the mRNA expression of heat shock protein (HSP)90AB1), DNA damage inducible transcript 3 (DDIT3), and early growth response (EGR)1. These tissues were also negative for the inflammatory (CD11b), fibrotic (fibronectin and α-smooth muscle actin), stress (HSP-47) and apoptotic (TUNEL assay) responses on the immunohistochemical analyses. The optical transmittance of corneas did not change significantly, and the inter-fibrillar distances of the corneal stroma evaluated with transmission electron microscopy were not significantly altered after THz exposure. These results provide the basis for future research work on the development of THz imaging system for its application in ophthalmology.
Collapse
Affiliation(s)
- Yu-Chi Liu
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore. .,Singapore National Eye Centre, Singapore, Singapore. .,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore.
| | - Lin Ke
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Steve Wu Qing Yang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Zhang Nan
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Ericia Pei Wen Teo
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Nyein Chan Lwin
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Molly Tzu-Yu Lin
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Isabelle Xin Yu Lee
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Anita Sook-Yee Chan
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore.,School of Chemical and Biomedcial Engineering, Nanyang Technological University, Singapore, Singapore.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Jodhbir S Mehta
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore
| |
Collapse
|
6
|
Marble CB, Yakovlev VV. Biomedical optics applications of advanced lasers and nonlinear optics. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-9. [PMID: 32329266 PMCID: PMC7177183 DOI: 10.1117/1.jbo.25.4.040902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
SIGNIFICANCE 2019 SPIE Photonics West conference hosted over 5000 presentations. Some important presentations in the Industrial Laser, Laser Source and Application (LASE) and Optoelectronics, Photonic Materials and Devices (OPTO) sections of the SPIE Photonics West conference have a risk of being overlooked by the biomedical community despite their implications for the field of biophotonics. We review some recent advances in the area of development coherent radiation sources in the infrared (IR), ultraviolet (UV), and terahertz (THz) regimes. AIM Recent advances in coherent radiation sources in the IR, deep UV, and THz regimes were outlined, and the importance of each presentation to one or more promising biomedical applications was assessed. APPROACH Presentations and proceedings from the LASE and OPTO sections were reviewed for inclusion. Emphasis was placed on talks from the Nonlinear Frequency Generation and Conversion: Materials and Devices XVIII conference, and the Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XII conference. Conference sections that directly focused on biomedical applications were excluded. RESULTS Enhanced IR supercontinuum generation with compact supercontinuum sources may allow for real-time biomarker detection and create new opportunities for imaging tissues using the third biological window (1600 to 1850 nm). Efficient methods to generate deep UV (200 to 260 nm) radiation allow for the study of biologically important molecules through techniques such as resonance Raman spectroscopy while avoiding fluorescence overlap. Likewise, novel and improved THz generation methods seek to bridge the "THz gap" that has previously limited biomedical applications. CONCLUSIONS Advances in coherent radiation sources in the IR, UV, and THz regimes have created new opportunities for biomedical optics research.
Collapse
Affiliation(s)
- Christopher B. Marble
- Texas A&M University, Department of Physics and Astronomy, College Station, Texas, United States
| | - Vladislav V. Yakovlev
- Texas A&M University, Department of Physics and Astronomy, College Station, Texas, United States
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| |
Collapse
|
7
|
Yao J, Ma J, Zhao J, Qi P, Li M, Lin L, Sun L, Wang X, Liu W, Wang Y. Corneal hydration assessment indicator based on terahertz time domain spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:2073-2084. [PMID: 32341867 PMCID: PMC7173912 DOI: 10.1364/boe.387826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
Terahertz technology has shown broad prospects for measuring corneal water content, which is an important parameter of ocular health. Based on terahertz time-domain spectroscopy, a new indicator named characteristic ratio (CR) of the sum of low (0.2-0.7 THz) and high (0.7-1.0 THz) frequency spectral intensities, for characterizing corneal hydration is introduced in this work. CR is calculated from the real-time reflection spectra after error elimination of ex vivo human corneal stroma samples which is collected during dehydration under natural conditions (temperature: 22.4 ± 0.3°C; humidity: 20.0 ± 3%). The corresponding relationships between CR and corneal water content are reported. Comparing the linear fitting results with the published similar study, the coefficients of variation of the fitting slope and intercept are 39.4% and 27.6% lower, respectively. This indicates that this approach has the potential to achieve corneal water content in-vivo detection in the future.
Collapse
Affiliation(s)
- Jiali Yao
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Jiaonan Ma
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| | - Jiehui Zhao
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Pengfei Qi
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Mengdi Li
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| | - Lie Lin
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lu Sun
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
- Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guangxi, China
| | - Xiaolei Wang
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Weiwei Liu
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Yan Wang
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| |
Collapse
|
8
|
Chen A, Osman OB, Harris ZB, Abazri A, Honkanen R, Arbab MH. Investigation of water diffusion dynamics in corneal phantoms using terahertz time-domain spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:1284-1297. [PMID: 32206409 PMCID: PMC7075598 DOI: 10.1364/boe.382826] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 05/08/2023]
Abstract
Perturbation of normal corneal water content is a common manifestation of many eye diseases. Terahertz (THz) imaging has the potential to serve as a clinical tool for screening and diagnosing such corneal diseases. In this study, we first investigate the diffusive properties of a corneal phantom using simultaneous THz time-domain spectroscopy (THz-TDS) and gravimetric measurements. We will then utilize a variable-thickness diffusion model combined with a stratified composite-media model to simulate changes in thickness, hydration profile, and the THz-TDS signal as a function of time. The simulated THz-TDS signals show very good agreement with the reflection measurements. Results show that the THz-TDS technique can be used to understand water diffusion dynamics in corneal phantoms as a step towards future in vivo quantitative hydration sensing.
Collapse
Affiliation(s)
- Andrew Chen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- Co-first authors with equal contribution
| | - Omar B. Osman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- Co-first authors with equal contribution
| | - Zachery B. Harris
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Azin Abazri
- Department of Ophthalmology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Robert Honkanen
- Department of Ophthalmology, Stony Brook University, Stony Brook, NY 11794, USA
| | - M. Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| |
Collapse
|
9
|
Liu YC, Ke L, Mehta JS. Evaluation of Corneal Oedema – Tools we Have and Those Under Investigation. ACTA ACUST UNITED AC 2019. [DOI: 10.17925/eor.2019.13.2.76] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
10
|
Sun Q, He Y, Liu K, Fan S, Parrott EPJ, Pickwell-MacPherson E. Recent advances in terahertz technology for biomedical applications. Quant Imaging Med Surg 2017; 7:345-355. [PMID: 28812001 DOI: 10.21037/qims.2017.06.02] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Terahertz instrumentation has improved significantly in recent years such that THz imaging systems have become more affordable and easier to use. THz systems can now be operated by non-THz experts greatly facilitating research into many potential applications. Due to the non-ionising nature of THz light and its high sensitivity to soft tissues, there is an increasing interest in biomedical applications including both in vivo and ex vivo studies. Additionally, research continues into understanding the origin of contrast and how to interpret terahertz biomedical images. This short review highlights some of the recent work in these areas and suggests some future research directions.
Collapse
Affiliation(s)
- Qiushuo Sun
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR, China
| | - Yuezhi He
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR, China
| | - Kai Liu
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR, China
| | - Shuting Fan
- School of Physics and Astrophysics (M013), The University of Western Australia Perth, WA 6009, Australia
| | - Edward P J Parrott
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR, China
| | - Emma Pickwell-MacPherson
- Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR, China
| |
Collapse
|
11
|
Dutta M, Bhalla AS, Guo R. THz Imaging of Skin Burn: Seeing the Unseen-An Overview. Adv Wound Care (New Rochelle) 2016; 5:338-348. [PMID: 27602253 PMCID: PMC4991599 DOI: 10.1089/wound.2015.0685] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/25/2016] [Indexed: 11/12/2022] Open
Abstract
Significance: This review article puts together all the studies performed so far in realizing terahertz (THz) spectra as a probing mechanism for burn evaluation, summarizing their experimental conditions, observations, outcomes, merits, and demerits, along with a comparative discussion of other currently used technologies to present the state of art in a condensed manner. The key features of this noncontact investigation technique like its precise burn depth analysis and the approaches it follows to convert the probed data into a quantitative measure have also been discussed in this article. Recent Advances: The current research developments in THz regime observed in device design technologies (like THz time domain spectrometer, quantum cascade THz lasers, THz single-photon detectors, etc.) and in understanding its unique properties (like nonionizing nature, penetrability through dry dielectrics, etc.) have motivated the research world to realize THz window as a potential candidate for burn detection. Critical Issues: Application of appropriate medical measure for burn injury is primarily subjective to proper estimation of burn depth. Tool modality distinguishing between partial and full-thickness burn contributing toward correct medical care is indeed awaited. Future Directions: The overview of THz imaging as a burn assessment tool as provided in this article will certainly help in further nurturing of this emerging diagnostic technique particularly in improving its detection and accompanied image processing methods so that the minute nuances captured by the THz beam can be correlated with the physiological-anatomical changes in skin structures, caused by burn, for better sensitivity, resolution, and quantitative analysis.
Collapse
Affiliation(s)
- Moumita Dutta
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, Texas
| | - Amar S. Bhalla
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, Texas
| | - Ruyan Guo
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, Texas
| |
Collapse
|
12
|
Taylor ZD, Garritano J, Sung S, Bajwa N, Bennett DB, Nowroozi B, Tewari P, Sayre JW, Hubschman JP, Deng SX, Brown ER, Grundfest WS. THz and mm-Wave Sensing of Corneal Tissue Water Content: In Vivo Sensing and Imaging Results. IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY 2015; 5:184-196. [PMID: 26161292 PMCID: PMC4493917 DOI: 10.1109/tthz.2015.2392628] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A pulsed terahertz (THz) imaging system and millimeter-wave reflectometer were used to acquire images and point measurements, respectively, of five rabbit cornea in vivo. These imaging results are the first ever produced of in vivo cornea. A modified version of a standard protocol using a gentle stream of air and a Mylar window was employed to slightly dehydrate healthy cornea. The sensor data and companion central corneal thickness (CCT) measurements were acquired every 10-15 min over the course of two hours using ultrasound pachymmetry.. Statistically significant positive correlations were established between CCT measurements and millimeter wave reflectivity. Local shifts in reflectivity contrast were observed in the THz imagery; however, the THz reflectivity did not display a significant correlation with thickness in the region probed by the 100 GHz and CCT measurements. This is explained in part by a thickness sensitivity at least 10× higher in the mm-wave than the THz systems. Stratified media and effective media modeling suggest that the protocol perturbed the thickness and not the corneal tissue water content (CTWC). To further explore possible etalon effects, an additional rabbit was euthanized and millimeter wave measurements were obtained during death induced edema. These observations represent the first time that the uncoupled sensing of CTWC and CCT have been achieved in vivo.
Collapse
Affiliation(s)
- Zachary D. Taylor
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - James Garritano
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - Shijun Sung
- Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Neha Bajwa
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - David B. Bennett
- Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Fitbit, San Francisco, CA 94105 USA
| | - Bryan Nowroozi
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Mimeo Labs Inc, Santa Monica, CA 90404 USA
| | - Priyamvada Tewari
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. She is now with Elsevier Life Science solutions, San Francisco, CA 94105 USA
| | - James W. Sayre
- Department of Biostatistics, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Jean-Pierre Hubschman
- Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Sophie X. Deng
- Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Elliott R. Brown
- Department. of Electrical Engineering, Wright State University, Dayton, OH 45435 USA
| | - Warren S. Grundfest
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| |
Collapse
|
13
|
Taylor ZD, Garritano J, Sung S, Bajwa N, Bennett DB, Nowroozi B, Tewari P, Sayre J, Hubschman JP, Deng S, Brown ER, Grundfest WS. THz and mm-Wave Sensing of Corneal Tissue Water Content: Electromagnetic Modeling and Analysis. IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY 2015; 5:170-183. [PMID: 26322247 PMCID: PMC4551413 DOI: 10.1109/tthz.2015.2392619] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Terahertz (THz) spectral properties of human cornea are explored as a function of central corneal thickness (CCT) and corneal water content, and the clinical utility of THz-based corneal water content sensing is discussed. Three candidate corneal tissue water content (CTWC) perturbations, based on corneal physiology, are investigated that affect the axial water distribution and total thickness. The THz frequency reflectivity properties of the three CTWC perturbations were simulated and explored with varying system center frequency and bandwidths (Q-factors). The modeling showed that at effective optical path lengths on the order of a wavelength the cornea presents a lossy etalon bordered by air at the anterior and the aqueous humor at the posterior. The simulated standing wave peak-to-valley ratio is pronounced at lower frequencies and its effect on acquired data can be modulated by adjusting the bandwidth of the sensing system. These observations are supported with experimental spectroscopic data. The results suggest that a priori knowledge of corneal thickness can be utilized for accurate assessments of corneal tissue water content. The physiologic variation of corneal thickness with respect to the wavelengths spanned by the THz band is extremely limited compared to all other structures in the body making CTWC sensing unique amongst all proposed applications of THz medical imaging.
Collapse
Affiliation(s)
- Zachary D. Taylor
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - James Garritano
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - Shijun Sung
- Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Neha Bajwa
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| | - David B. Bennett
- Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Fitbit, San Francisco, CA 94105 USA
| | - Bryan Nowroozi
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Mimeo Labs Inc, Santa Monica, CA 90404 USA
| | - Priyamvada Tewari
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. She is now with Elsevier Life Science solutions, San Francisco, CA 94105 USA
| | - James Sayre
- Department of Biostatistics, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Jean-Pierre Hubschman
- Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Sophie Deng
- Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA
| | - Elliott R. Brown
- Department. of Electrical Engineering, Wright State University, Dayton, OH 45435 USA
| | - Warren S. Grundfest
- Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA
| |
Collapse
|
14
|
Hwang Y, Ahn J, Mun J, Bae S, Jeong YU, Vinokurov NA, Kim P. In vivo analysis of THz wave irradiation induced acute inflammatory response in skin by laser-scanning confocal microscopy. OPTICS EXPRESS 2014; 22:11465-75. [PMID: 24921268 DOI: 10.1364/oe.22.011465] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The recent development of THz sources in a wide range of THz frequencies and power levels has led to greatly increased interest in potential biomedical applications such as cancer and burn wound diagnosis. However, despite its importance in realizing THz wave based applications, our knowledge of how THz wave irradiation can affect a live tissue at the cellular level is very limited. In this study, an acute inflammatory response caused by pulsed THz wave irradiation on the skin of a live mouse was analyzed at the cellular level using intravital laser-scanning confocal microscopy. Pulsed THz wave (2.7 THz, 4 μs pulsewidth, 61.4 μJ per pulse, 3Hz repetition), generated using compact FEL, was used to irradiate an anesthetized mouse's ear skin with an average power of 260 mW/cm(2) for 30 minutes using a high-precision focused THz wave irradiation setup. In contrast to in vitro analysis using cultured cells at similar power levels of CW THz wave irradiation, no temperature change at the surface of the ear skin was observed when skin was examined with an IR camera. To monitor any potential inflammatory response, resident neutrophils in the same area of ear skin were repeatedly visualized before and after THz wave irradiation using a custom-built laser-scanning confocal microscopy system optimized for in vivo visualization. While non-irradiated control skin area showed no changes in the number of resident neutrophils, a massive recruitment of newly infiltrated neutrophils was observed in the THz wave irradiated skin area after 6 hours, which suggests an induction of acute inflammatory response by the pulsed THz wave irradiation on the skin via a non-thermal process.
Collapse
|
15
|
Intense THz pulses down-regulate genes associated with skin cancer and psoriasis: a new therapeutic avenue? Sci Rep 2014; 3:2363. [PMID: 23917523 PMCID: PMC3734481 DOI: 10.1038/srep02363] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/11/2013] [Indexed: 01/23/2023] Open
Abstract
Terahertz (THz) radiation lies between the infrared and microwave regions of the electromagnetic spectrum and is non-ionizing. We show that exposure of artificial human skin tissue to intense, picosecond-duration THz pulses affects expression levels of numerous genes associated with non-melanoma skin cancers, psoriasis and atopic dermatitis. Genes affected by intense THz pulses include nearly half of the epidermal differentiation complex (EDC) members. EDC genes, which are mapped to the chromosomal human region 1q21, encode for proteins that partake in epidermal differentiation and are often overexpressed in conditions such as psoriasis and skin cancer. In nearly all the genes differentially expressed by exposure to intense THz pulses, the induced changes in transcription levels are opposite to disease-related changes. The ability of intense THz pulses to cause concerted favorable changes in the expression of multiple genes implicated in inflammatory skin diseases and skin cancers suggests potential therapeutic applications of intense THz pulses.
Collapse
|