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Belcastro L, Jonasson H, Saager RB. Multi-frequency spatial frequency domain imaging: a depth-resolved optical scattering model to isolate scattering contrast in thin layers of skin. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:046003. [PMID: 38650893 PMCID: PMC11033580 DOI: 10.1117/1.jbo.29.4.046003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 03/24/2024] [Accepted: 03/28/2024] [Indexed: 04/25/2024]
Abstract
Significance Current methods for wound healing assessment rely on visual inspection, which gives qualitative information. Optical methods allow for quantitative non-invasive measurements of optical properties relevant to wound healing. Aim Spatial frequency domain imaging (SFDI) measures the absorption and reduced scattering coefficients of tissue. Typically, SFDI assumes homogeneous tissue; however, layered structures are present in skin. We evaluate a multi-frequency approach to process SFDI data that estimates depth-specific scattering over differing penetration depths. Approach Multi-layer phantoms were manufactured to mimic wound healing scattering contrast in depth. An SFDI device imaged these phantoms and data were processed according to our multi-frequency approach. The depth sensitive data were then compared with a two-layer scattering model based on light fluence. Results The measured scattering from the phantoms changed with spatial frequency as our two-layer model predicted. The performance of two δ - P 1 models solutions for SFDI was consistently better than the standard diffusion approximation. Conclusions We presented an approach to process SFDI data that returns depth-resolved scattering contrast. This method allows for the implementation of layered optical models that more accurately represent physiologic parameters in thin tissue structures as in wound healing.
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Affiliation(s)
- Luigi Belcastro
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Hanna Jonasson
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
| | - Rolf B. Saager
- Linköping University, Department of Biomedical Engineering, Linköping, Sweden
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2
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Dinish US, Logan S, Balasundaram G, Xinhui VT, Vinod Ram K, Ruochong Z, Renzhe B, Silvani S, Hua Cheng K, Xia X, Giap Hean G, Choolani M, Olivo M. Diffuse reflectance spectroscopy and imaging for non-invasive objective assessment of genitourinary syndrome of menopause: a pilot study. Sci Rep 2024; 14:1085. [PMID: 38212347 PMCID: PMC10784538 DOI: 10.1038/s41598-023-49655-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/11/2023] [Indexed: 01/13/2024] Open
Abstract
The genitourinary symptom of menopause (GSM) affects up to 65% of women, resulting in symptoms such as vulvovaginal dryness, discomfort, and dysuria, which significantly impacts quality of life. The current assessment methods rely on subjective questionnaires that can be influenced by individual differences, as well as invasive measurements that are time-consuming and not easily accessible. In this study, we explore the potential of a non-invasive and objective assessment tool called diffuse reflectance spectroscopy and imaging (DRSI) to evaluate tissue chromophores, including water, lipid, oxyhemoglobin, and deoxyhemoglobin. These measurements provide information about moisture content, lipid levels, oxygen saturation, and blood fraction, which can serve as surrogate markers for genital estrogen levels. Our findings reveal distinct differences in these chromophores among pre, peri, and postmenopausal subjects. By using lipid and blood fraction tissue chromophores in a K-Nearest Neighbour classifier model, we achieved a prediction accuracy of 65% compared to vaginal maturation index (VMI) that is clinically used to assess estrogen-related hormonal changes. When age was included as the third feature, the accuracy increased to 78%. We believe that by refining the study protocol and configuring the fiber probe to examine tissue chromophores both in the superficial vulva skin for epidermal water content and the deeper layers, DRSI has the potential to provide objective diagnosis and aid in monitoring the treatment outcome of GSM.
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Affiliation(s)
- U S Dinish
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore.
| | - Susan Logan
- Department of Obstetrics and Gynaecology, NUS Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, NUHS Tower Block, Level 12, Singapore, 119228, Singapore.
- Department of Obstetrics and Gynaecology, National University Hospital, 1E Kent Ridge Road, NUHS Tower Block, Level 12, Singapore, 119228, Singapore.
- Department of Sexual and Reproductive Health, NHS Grampian, Aberdeen, Scotland, UK.
| | - Ghayathri Balasundaram
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore
| | - Valerie Teo Xinhui
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore
| | - Keertana Vinod Ram
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore
| | - Zhang Ruochong
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore
| | - Bi Renzhe
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore
| | - Steffie Silvani
- Department of Obstetrics and Gynaecology, National University Hospital, 1E Kent Ridge Road, NUHS Tower Block, Level 12, Singapore, 119228, Singapore
| | - Kee Hua Cheng
- Department of Pathology, National University Hospital, 5 Lower Kent Ridge Road, Singapore, 119074, Singapore
| | - Xu Xia
- Department of Pathology, National University Hospital, 5 Lower Kent Ridge Road, Singapore, 119074, Singapore
| | - Goh Giap Hean
- Department of Pathology, National University Hospital, 5 Lower Kent Ridge Road, Singapore, 119074, Singapore
| | - Mahesh Choolani
- Department of Obstetrics and Gynaecology, NUS Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, NUHS Tower Block, Level 12, Singapore, 119228, Singapore
- Department of Obstetrics and Gynaecology, National University Hospital, 1E Kent Ridge Road, NUHS Tower Block, Level 12, Singapore, 119228, Singapore
| | - Malini Olivo
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore.
- A*STAR Skin Research Labs (A*SRL), Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, #07-01 Nanos, Singapore, 138669, Republic of Singapore.
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3
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Hasan MZ, Saha PS, Korfhage MO, Zhu C. Non-contact optical spectroscopy for tumor-sensitive diffuse reflectance and fluorescence measurements on murine subcutaneous tissue models: Monte Carlo modeling and experimental validations. BIOMEDICAL OPTICS EXPRESS 2023; 14:5418-5439. [PMID: 37854556 PMCID: PMC10581788 DOI: 10.1364/boe.502778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/12/2023] [Accepted: 09/16/2023] [Indexed: 10/20/2023]
Abstract
Fiber-optic probes are commonly used in biomedical optical spectroscopy platforms for light delivery and collection. At the same time, it was reported that the inconsistent probe-sample contact could induce significant distortions in measured optical signals, which consequently cause large analysis errors. To address this challenge, non-contact optical spectroscopy has been explored for tissue characterizations. However, existing non-contact optical spectroscopy platforms primarily focused on diffuse reflectance measurements and may still use a fiber probe in which the probe was imaged onto the tissue surface using a lens, which serves as a non-contact probe for the measurements. Here, we report a fiber-probe-free, dark-field-based, non-contact optical spectroscopy for both diffuse reflectance and fluorescence measurements on turbid medium and tissues. To optimize the system design, we developed a novel Monte Carlo method to simulate such a non-contact setup for both diffuse reflectance and fluorescence measurements on murine subcutaneous tissue models with a spherical tumor-like target. We performed Monte Carlo simulations to identify the most tumor-sensitive configurations, from which we found that both the depth of the light focal point in tissue and the lens numerical aperture would dramatically affect the system's tumor detection sensitivity. We then conducted tissue-mimicking phantom studies to solidify these findings. Our reported Monte Carlo technique can be a useful computational tool for designing non-contact optical spectroscopy systems. Our non-contact optical setup and experimental findings will potentially offer a new approach for sensitive optical monitoring of tumor physiology in biological models using a non-contact optical spectroscopy platform to advance cancer research.
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Affiliation(s)
- Md Zahid Hasan
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Pranto Soumik Saha
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Madison O. Korfhage
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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4
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Yang CC, Yen YY, Hsu CK, Cheng NY, Tzeng SY, Chou SJ, Chang JM, Tseng SH. Investigation of water bonding status of normal and psoriatic skin in vivo using diffuse reflectance spectroscopy. Sci Rep 2021; 11:8901. [PMID: 33903688 PMCID: PMC8076238 DOI: 10.1038/s41598-021-88530-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/12/2021] [Indexed: 11/09/2022] Open
Abstract
Psoriasis affects more than 125 million people worldwide, and the diagnosis and treatment efficacy evaluation of the disease mainly rely on clinical assessments that could be subjective. Our previous study showed that the skin erythema level could be quantified using diffuse reflectance spectroscopy (DRS), and the hemoglobin concentration of most psoriatic lesion was higher than that of its adjacent uninvolved skin. While the compromised epidermal barrier function has been taken as the major cause of clinical manifestation of skin dryness and inflammation of psoriasis, very few methods can be used to effectively evaluate this function. In this study, we investigate the near infrared spectroscopic features of psoriatic (n = 21) and normal (n = 21) skin that could link to the epidermal barrier function. From the DRS measurements, it was found that the water bonding status and light scattering properties of psoriasis are significantly different from those of uninvolved or normal skin. The connection between these parameters to the epidermal barrier function and morphology will be discussed. Our results suggest that objective evaluation of epidermal barrier function of psoriasis could be achieved using a simple DRS system.
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Affiliation(s)
- Chao-Chun Yang
- Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C
| | - Yun-Yo Yen
- Department of Photonics, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C
| | - Chao-Kai Hsu
- Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C..
| | - Nan-Yu Cheng
- Department of Photonics, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C
| | - Shih-Yu Tzeng
- Department of Photonics, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C
| | - Shih-Jay Chou
- Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, 300, Taiwan, R.O.C
| | - Jun-Ming Chang
- Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, 300, Taiwan, R.O.C
| | - Sheng-Hao Tseng
- Department of Photonics, National Cheng Kung University, Tainan, 701, Taiwan, R.O.C..
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5
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Carrico E, Sun T, Zhu C. Numerical investigation of depth-sensitive diffuse reflectance and fluorescence measurements on murine subcutaneous tissue with growing solid tumors. BIOMEDICAL OPTICS EXPRESS 2020; 11:6311-6323. [PMID: 33282492 PMCID: PMC7687953 DOI: 10.1364/boe.405321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 05/08/2023]
Abstract
In most biomedical optical spectroscopy platforms, a fiber-probe consisting of single or multiple illumination and collection fibers was commonly used for the delivery of illuminating light and the collection of emitted light. Typically, the signals from all collection fibers were combined and then sampled to characterize tissue samples. Such simple averaged optical measurements may induce significant errors for in vivo tumor characterization, especially in longitudinal studies where the tumor size and location vary with tumor stages. In this study, we utilized the Monte Carlo technique to optimize the fiber-probe geometries of a spectroscopy platform to enable tumor-sensitive diffuse reflectance and fluorescence measurements on murine subcutaneous tissues with growing solid tumors that have different sizes and depths. Our data showed that depth-sensitive techniques offer improved sensitivity in tumor detection compared to the simple averaged approach in both reflectance and fluorescence measurements. Through the numerical studies, we optimized the source-detector distances, fiber diameters, and numerical apertures for sensitive measurement of small solid tumors with varying size and depth buried in murine subcutaneous tissues. Our study will advance the design of a fiber-probe in an optical spectroscopy system that can be used for longitudinal tumor metabolism and vasculature monitoring.
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Affiliation(s)
- Evan Carrico
- Department of Electrical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Tengfei Sun
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Caigang Zhu
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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6
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Park J, Ha M, Yu S, Jung B. Fabrication of various optical tissue phantoms by the spin-coating method. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:65008. [PMID: 27367252 DOI: 10.1117/1.jbo.21.6.065008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
Although numerous studies have been performed to fabricate various optical tissue phantom (OTP) models, the fabrication of OTPs that simulate skin layers is laborious and time-consuming owing to the intricate characteristics of skin tissue. This study presents various OTP models that optically and structurally simulate the epidermis–dermis skin layer. The spin-coating method was employed to reproduce a uniform thin layer that mimics the epidermis layer, and the fabrication parameters were optimized for epoxy and silicone reference materials. Various OTP models simulating blood vessels and hyperpigmentation lesions were fabricated using the two reference materials to determine their feasibility. The suitability of each of the two reference materials for OTP fabrication was qualitatively evaluated by comparing the quality of the OTP models.
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7
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Rohde SB, Kim AD. Convolution model of the diffuse reflectance for layered tissues. OPTICS LETTERS 2014; 39:154-157. [PMID: 24365846 DOI: 10.1364/ol.39.000154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present an explicit model for the diffuse reflectance due to a collimated beam of light incident normally on layered tissues. This model is derived using the corrected diffusion approximation applied to a layered medium, and it takes the form of a convolution with an explicit kernel and the incident beam profile. This model corrects the standard diffusion approximation over all source-detector separation distances provided the beam is sufficiently wide compared to the scattering mean free path. We validate this model through comparison with Monte Carlo simulations. Then we use this model to estimate the optical properties of an epithelial layer from Monte Carlo simulation data. Using measurements at small source-detector separations and this model, we are able to estimate the absorption coefficient, scattering coefficient, and anisotropy factor of epithelial tissues efficiently with reasonable accuracy.
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8
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Gomes AJ, Backman V. Algorithm for automated selection of application-specific fiber-optic reflectance probes. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:27012. [PMID: 23455876 PMCID: PMC3585420 DOI: 10.1117/1.jbo.18.2.027012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 01/11/2013] [Accepted: 01/15/2013] [Indexed: 05/19/2023]
Abstract
Several optical techniques and fiber-optic probe systems have been designed to measure the optical properties of tissue. While a wide range of options is often beneficial, it poses a problem to investigators selecting which method to use for their biomedical application of interest. We present a methodology to optimally select a probe that matches the application requirements. Our method is based both on matching a probe's mean sampling depth with the optimal diagnostic depth of the clinical application and on choosing a probe whose interrogation depth and path length is the least sensitive to alterations in the target medium's optical properties. Satisfying these requirements ensures that the selected probe consistently assesses the relevant tissue volume with minimum variability. To aid in probe selection, we have developed a publicly available graphical user interface that takes the desired sampling depth and optical properties of the medium as its inputs and automatically ranks different techniques in their ability to robustly target the desired depth. Techniques investigated include single fiber spectroscopy, differential path length spectroscopy, polarization-gating, elastic light scattering spectroscopy, and diffuse reflectance. The software has been applied to biological case studies.
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Affiliation(s)
- Andrew J. Gomes
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60218
| | - Vadim Backman
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60218
- Address all correspondence to: Vadim Backman, Northwestern University, Department of Biomedical Engineering, Evanston, Illinois 60218. Tel: (847) 491-3536; Fax: (847) 491-4928; E-mail:
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9
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Saager RB, Hassan KM, Kondru C, Durkin AJ, Kelly KM. Quantitative near infrared spectroscopic analysis of Q-Switched Nd:YAG treatment of generalized argyria. Lasers Surg Med 2013; 45:15-21. [PMID: 23322674 DOI: 10.1002/lsm.22084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2012] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Generalized argyria is a blue-gray hyperpigmentation of the skin resulting from ingestion or application of silver compounds, such as silver colloid. Case reports have noted improvement after Q-Switched Neodymium-Yttrium Aluminum Garnet laser (1,064 nm QS Nd:YAG) laser treatment to small surface areas. No reports have objectively monitored laser treatment of generalized argyria over large areas of skin, nor have long-term outcomes been evaluated. STUDY DESIGN/MATERIALS AND METHODS An incremental treatment plan was developed for a subject suffering from argyria. A quantitative near infrared spectroscopic measurement technique was employed to non-invasively analyze tissue-pigment characteristics pre- and post-laser treatment. Post-treatment measurements were collected at weeks 1, 2, 3, and 4, and again at 1 year. RESULTS Immediate apparent removal of pigment was observed with 1 Q-switched 1,064 nm Nd:YAG laser treatment (3-6 mm spot; 0.8-2 J/cm(2) ) per area. Entire face, neck, upper chest, and arms were treated over multiple sessions. Treatments were very painful and general anesthesia was utilized in order to treat large areas. Near-infrared spectroscopy was used to characterize and quantify the concentration of silver particles in the dermis based on the absorption features of the silver particles as well as the optical scattering effects they impart. We were able to estimate that there was, on average, 0.042 mg/ml concentration of silver prior to treatment and that these levels went below the minimum detectable limit of the instrument post-treatment. There was no recurrence of discoloration over the 1-year study period. CONCLUSION QS 1,064 nm laser treatment of argyria is a viable method to restore normal skin pigmentation with no evidence of recurrence over study period. Quantitative spectroscopic measurements: (1) confirmed dyspigmentation was due to silver, (2) validated our clinical assessment of no recurrence up to 1-year post-treatment, and (3) indicated no collateral tissue damage with treatments.
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Affiliation(s)
- Rolf B Saager
- Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine, California 92617, USA
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10
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Saager RB, Hassan KM, Kondru C, Durkin AJ, Kelly KM. Quantitative near infrared spectroscopic analysis of Q-Switched Nd:YAG treatment of generalized argyria. Lasers Surg Med 2013. [PMID: 23322674 DOI: 10.1002/lsm.v45.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Generalized argyria is a blue-gray hyperpigmentation of the skin resulting from ingestion or application of silver compounds, such as silver colloid. Case reports have noted improvement after Q-Switched Neodymium-Yttrium Aluminum Garnet laser (1,064 nm QS Nd:YAG) laser treatment to small surface areas. No reports have objectively monitored laser treatment of generalized argyria over large areas of skin, nor have long-term outcomes been evaluated. STUDY DESIGN/MATERIALS AND METHODS An incremental treatment plan was developed for a subject suffering from argyria. A quantitative near infrared spectroscopic measurement technique was employed to non-invasively analyze tissue-pigment characteristics pre- and post-laser treatment. Post-treatment measurements were collected at weeks 1, 2, 3, and 4, and again at 1 year. RESULTS Immediate apparent removal of pigment was observed with 1 Q-switched 1,064 nm Nd:YAG laser treatment (3-6 mm spot; 0.8-2 J/cm(2) ) per area. Entire face, neck, upper chest, and arms were treated over multiple sessions. Treatments were very painful and general anesthesia was utilized in order to treat large areas. Near-infrared spectroscopy was used to characterize and quantify the concentration of silver particles in the dermis based on the absorption features of the silver particles as well as the optical scattering effects they impart. We were able to estimate that there was, on average, 0.042 mg/ml concentration of silver prior to treatment and that these levels went below the minimum detectable limit of the instrument post-treatment. There was no recurrence of discoloration over the 1-year study period. CONCLUSION QS 1,064 nm laser treatment of argyria is a viable method to restore normal skin pigmentation with no evidence of recurrence over study period. Quantitative spectroscopic measurements: (1) confirmed dyspigmentation was due to silver, (2) validated our clinical assessment of no recurrence up to 1-year post-treatment, and (3) indicated no collateral tissue damage with treatments.
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Affiliation(s)
- Rolf B Saager
- Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine, California 92617, USA
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11
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Luedtke MA, Papazoglou E, Neidrauer M, Kollias N. Wavelength effects on contrast observed with reflectance in vivo confocal laser scanning microscopy. Skin Res Technol 2010; 15:482-8. [PMID: 19832962 DOI: 10.1111/j.1600-0846.2009.00394.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND/PURPOSE The ability to optically section live biological tissue in vivo with laser light is made possible by confocal laser scanning microscopy (CLSM). In this work, the effects of changing the wavelength of incident light used for CLSM imaging of human skin are reported and analyzed. METHODS Optical phantoms and the skin of eight human volunteers were imaged using CLSM systems having three different incident light wavelengths (405, 785, and 830 nm). RESULTS Qualitative and quantitative differences were observed between images obtained at each wavelength, despite the proximity of the two near infrared 785 and 830 nm wavelengths. Furthermore, the penetration depth achieved with the 405 nm CLSM permitted imaging into the papillary dermis. CONCLUSION The laser wavelength used in CLSM reflectance imaging is important to properly understand and resolve different biological structures within human skin.
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Affiliation(s)
- Michael A Luedtke
- Johnson & Johnson Consumer and Personal Products Worldwide, Skillman, NJ 08558, USA
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12
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Tseng SH, Hayakawa C, Spanier J, Durkin AJ. Investigation of a probe design for facilitating the uses of the standard photon diffusion equation at short source-detector separations: Monte Carlo simulations. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:054043. [PMID: 19895144 PMCID: PMC2778761 DOI: 10.1117/1.3253386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/26/2009] [Accepted: 08/28/2009] [Indexed: 05/19/2023]
Abstract
We design a special diffusing probe to investigate the optical properties of human skin in vivo. The special geometry of the probe enables a modified two-layer (MTL) diffusion model to precisely describe the photon transport even when the source-detector separation is shorter than 3 mean free paths. We provide a frequency domain comparison between the Monte Carlo model and the diffusion model in both the MTL geometry and conventional semiinfinite geometry. We show that using the Monte Carlo model as a benchmark method, the MTL diffusion theory performs better than the diffusion theory in the semiinfinite geometry. In addition, we carry out Monte Carlo simulations with the goal of investigating the dependence of the interrogation depth of this probe on several parameters including source-detector separation, sample optical properties, and properties of the diffusing high-scattering layer. From the simulations, we find that the optical properties of samples modulate the interrogation volume greatly, and the source-detector separation and the thickness of the diffusing layer are the two dominant probe parameters that impact the interrogation volume. Our simulation results provide design guidelines for a MTL geometry probe.
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Affiliation(s)
- Sheng-Hao Tseng
- National Cheng-Kung University, Department of Electro-Optical Engineering, 1 University Road, Tainan, Taiwan.
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13
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Tseng SH, Grant A, Durkin AJ. In vivo determination of skin near-infrared optical properties using diffuse optical spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:014016. [PMID: 18315374 PMCID: PMC2626348 DOI: 10.1117/1.2829772] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We develop a superficial diffusing probe with a 3 mm source-detector separation that can be used in combination with diffuse optical spectroscopic (DOS) methods to noninvasively determine full-spectrum optical properties of superficial in vivo skin in the wavelength range from 650 to 1000 nm. This new probe uses a highly scattering layer to diffuse photons emitted from a collimated light source and relies on a two-layer diffusion model to determine tissue absorption coefficient mu a and reduced scattering coefficient mu's. By employing the probe to measure two-layer phantoms that mimic the optical properties of skin, we demonstrate that the probe has an interrogation depth of 1 to 2 mm. We carry out SSFDPM (steady state frequency-domain photon migration) measurements using this new probe on the volar forearm and palm of 15 subjects, including five subjects of African descent, five Asians, and five Caucasians. The optical properties of in vivo skin determined using the superficial diffusing probe show considerable similarity to published optical properties of carefully prepared ex vivo epidermis+dermis.
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Affiliation(s)
- Sheng-Hao Tseng
- University of California, Irvine, Beckman Laser Institute, Laser Microbeam and Medical Program, Irvine, California 92617, USA.
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