1
|
Shimojo Y, Nishimura T, Tsuruta D, Ozawa T, Chan HHL, Kono T. Wavelength-dependent threshold fluences for melanosome disruption to evaluate the treatment of pigmented lesions with 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers. Lasers Surg Med 2024; 56:404-418. [PMID: 38436524 DOI: 10.1002/lsm.23773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND AND OBJECTIVES A threshold fluence for melanosome disruption has the potential to provide a robust numerical indicator for establishing clinical endpoints for pigmented lesion treatment using a picosecond laser. Although the thresholds for a 755-nm picosecond laser were previously reported, the wavelength dependence has not been investigated. In this study, wavelength-dependent threshold fluences for melanosome disruption were determined. Using a mathematical model based on the thresholds, irradiation parameters for 532-, 730-, 755-, 785-, and 1064-nm picosecond laser treatments were evaluated quantitatively. STUDY DESIGN/MATERIALS AND METHODS A suspension of melanosomes extracted from porcine eyes was irradiated using picosecond lasers with varying fluence. The mean particle size of the irradiated melanosomes was measured by dynamic light scattering, and their disruption was observed by scanning electron microscopy to determine the disruption thresholds. A mathematical model was developed, combined with the threshold obtained and Monte Carlo light transport to calculate irradiation parameters required to disrupt melanosomes within the skin tissue. RESULTS The threshold fluences were determined to be 0.95, 2.25, 2.75, and 6.50 J/cm² for 532-, 730-, 785-, and 1064-nm picosecond lasers, respectively. The numerical results quantitatively revealed the relationship between irradiation wavelength, incident fluence, and spot size required to disrupt melanosomes distributed at different depths in the skin tissue. The calculated irradiation parameters were consistent with clinical parameters that showed high efficacy with a low incidence of complications. CONCLUSION The wavelength-dependent thresholds for melanosome disruption were determined. The results of the evaluation of irradiation parameters from the threshold-based analysis provided numerical indicators for setting the clinical endpoints for 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers.
Collapse
Affiliation(s)
- Yu Shimojo
- Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
- Graduate School of Engineering, Osaka University, Osaka, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | | | - Daisuke Tsuruta
- Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Toshiyuki Ozawa
- Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Henry Hin Lee Chan
- Department of Medicine, Division of Dermatology, The University of Hong Kong, Hong Kong SAR, China
| | - Taro Kono
- Department of Plastic Surgery, School of Medicine, Tokai University, Kanagawa, Japan
| |
Collapse
|
2
|
Teranishi R, Ozawa T, Katayama B, Shimojo Y, Ito N, Awazu K, Tsuruta D. Effect of photodynamic therapy with 5-aminolevulinic acid and EDTA-2Na against mixed infection of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Photodermatol Photoimmunol Photomed 2024; 40:e12959. [PMID: 38528712 DOI: 10.1111/phpp.12959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 01/27/2024] [Accepted: 02/22/2024] [Indexed: 03/27/2024]
Abstract
BACKGROUND The increasing abundance of drug-resistant bacteria is a global threat. Photodynamic therapy is an entirely new, non-invasive method for treating infections caused by antibiotic-resistant strains. We previously described the bactericidal effect of photodynamic therapy on infections caused by a single type of bacterium. We showed that gram-positive and gram-negative bacteria could be killed with 5-aminolevulic acid and 410 nm light, respectively. However, clinically, mixed infections are common and difficult to treat. OBJECTIVE We investigated the bactericidal effects of photodynamic therapy on mixed infections of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. METHODS We compared bacterial growth with and without photodynamic therapy in vitro. Then, in vivo, we studied mixed infections in a mouse skin ulcer model. We evaluated the rates of ulcer area reduction and transitions to healing in treated and untreated mice. In addition, a comparison was made between PDT and existing topical drugs. RESULTS We found that photodynamic therapy markedly reduced the growth of both methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, in culture, and it reduced the skin ulcer areas in mice. PDT was also more effective than existing topical medicines. CONCLUSION This study showed that photodynamic therapy had antibacterial effects against a mixed infection of gram-positive and gram-negative bacteria, and it promoted skin ulcer healing. These results suggested that photodynamic therapy could be effective in both single- and mixed-bacterial infections.
Collapse
Affiliation(s)
- Rie Teranishi
- Department of Dermatology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Toshiyuki Ozawa
- Department of Dermatology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
- Research Center for Infectious Disease Sciences, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Bunpei Katayama
- Department of Dermatology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Yu Shimojo
- Department of Dermatology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
- Medical Beam Physics Laboratory, Osaka University Graduate School of Engineering, Osaka, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Nobuhisa Ito
- Medical Beam Physics Laboratory, Osaka University Graduate School of Engineering, Osaka, Japan
| | - Kunio Awazu
- Medical Beam Physics Laboratory, Osaka University Graduate School of Engineering, Osaka, Japan
| | - Daisuke Tsuruta
- Department of Dermatology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
- Research Center for Infectious Disease Sciences, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| |
Collapse
|
3
|
Imanishi H, Nishimura T, Shimojo Y, Awazu K. Deep learning based depth map estimation of protoporphyrin IX in turbid media using dual wavelength excitation fluorescence. Biomed Opt Express 2023; 14:5254-5266. [PMID: 37854564 PMCID: PMC10581804 DOI: 10.1364/boe.500022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/09/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023]
Abstract
This study presents a depth map estimation of fluorescent objects in turbid media, such as biological tissue based on fluorescence observation by two-wavelength excitation and deep learning-based processing. A U-Net-based convolutional neural network is adapted for fluorophore depth maps from the ratiometric information of the two-wavelength excitation fluorescence. The proposed method offers depth map estimation from wide-field fluorescence images with rapid processing. The feasibility of the proposed method was demonstrated experimentally by estimating the depth map of protoporphyrin IX, a recognized cancer biomarker, at different depths within an optical phantom.
Collapse
Affiliation(s)
- Hinano Imanishi
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan
| | - Takahiro Nishimura
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan
| | - Yu Shimojo
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan
- Graduate School of Medicine, Osaka Metropolitan University, Asahimachi 1-4-3, Abeno-ku, Osaka 545-8585, Japan
- Research Fellow of Japan Society for the Promotion of Science, Kojimachi 5-3-1, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan
- Global Center for Medical Engineering and Informatics, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan
| |
Collapse
|
4
|
Shimojo Y, Sudo K, Nishimura T, Ozawa T, Tsuruta D, Awazu K. Transient simulation of laser ablation based on Monte Carlo light transport with dynamic optical properties model. Sci Rep 2023; 13:11898. [PMID: 37488156 PMCID: PMC10366136 DOI: 10.1038/s41598-023-39026-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023] Open
Abstract
Laser ablation is a minimally invasive therapeutic technique to denature tumors through coagulation and/or vaporization. Computational simulations of laser ablation can evaluate treatment outcomes quantitatively and provide numerical indices to determine treatment conditions, thus accelerating the technique's clinical application. These simulations involve calculations of light transport, thermal diffusion, and the extent of thermal damage. The optical properties of tissue, which govern light transport through the tissue, vary during heating, and this affects the treatment outcomes. Nevertheless, the optical properties in conventional simulations of coagulation and vaporization remain constant. Here, we propose a laser ablation simulation based on Monte Carlo light transport with a dynamic optical properties (DOP) model. The proposed simulation is validated by performing optical properties measurements and laser irradiation experiments on porcine liver tissue. The DOP model showed the replicability of the changes in tissue optical properties during heating. Furthermore, the proposed simulation estimated coagulation areas that were comparable to experimental results at low-power irradiation settings and provided more than 2.5 times higher accuracy when calculating coagulation and vaporization areas than simulations using static optical properties at high-power irradiation settings. Our results demonstrate the proposed simulation's applicability to coagulation and vaporization region calculations in tissue for retrospectively evaluating the treatment effects of laser ablation.
Collapse
Affiliation(s)
- Yu Shimojo
- Graduate School of Medicine, Osaka Metropolitan University, Asahimachi 1-4-3, Abeno-ku, Osaka, 545-8585, Japan.
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
- Research Fellow of Japan Society for the Promotion of Science, Kojimachi 5-3-1, Chiyoda-ku, Tokyo, 102-0083, Japan.
| | - Kazuma Sudo
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Takahiro Nishimura
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
| | - Toshiyuki Ozawa
- Graduate School of Medicine, Osaka Metropolitan University, Asahimachi 1-4-3, Abeno-ku, Osaka, 545-8585, Japan
| | - Daisuke Tsuruta
- Graduate School of Medicine, Osaka Metropolitan University, Asahimachi 1-4-3, Abeno-ku, Osaka, 545-8585, Japan
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
- Global Center for Medical Engineering and Informatics, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
5
|
Shimojo Y, Nishimura T, Ozawa T, Tsuruta D, Awazu K. Nonlinear absorption-based analysis of energy deposition in melanosomes for 532-nm short-pulsed laser skin treatment. Lasers Surg Med 2023; 55:305-315. [PMID: 36786528 DOI: 10.1002/lsm.23642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/15/2023]
Abstract
BACKGROUND AND OBJECTIVES The clinical use of 532-nm short-pulsed lasers has provided effective treatment of epidermal pigmented lesions. However, the detection of significant differences in treatment effects between picosecond and nanosecond lasers has still varied among clinical studies. For robust evaluation of the differences based on the treatment mechanism, this study presents a nonlinear absorption-based analysis of energy deposition in melanosomes for 532-nm short-pulsed laser treatment. STUDY DESIGN/MATERIALS AND METHODS Nonlinear absorption by melanin is modeled based on sequential two-photon absorption. Absorption cross-sections and nonradiative lifetimes of melanin, which are necessary for the nonlinear absorption-based analysis, are determined from transmittance measurement. Using the model and parameters, energy deposition in melanosomes was calculated with varying fluence and pulse width settings, including actual clinical parameters. RESULTS The energy deposition in melanosomes increased with shorter laser pulses, and subnanosecond laser pulses were found to be most efficient. The comparison of energy deposition calculated using clinical parameters demonstrated the differences in treatment effects between picosecond and nanosecond lasers reported in clinical studies. CONCLUSION The nonlinear absorption-based analysis provides quantitative evidence for the safety and efficacy evaluation of short-pulsed laser treatments, which may lead to the establishment of numerical indices for determining treatment conditions. Future studies considering the effects of the surrounding tissue on energy deposition in melanosomes will be needed.
Collapse
Affiliation(s)
- Yu Shimojo
- Graduate School of Engineering, Osaka University, Osaka, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | | | - Toshiyuki Ozawa
- Department of Dermatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Daisuke Tsuruta
- Department of Dermatology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, Japan
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, Osaka, Japan
- Global Center for Medical Engineering and Informatics, Osaka University, Osaka, Japan
| |
Collapse
|
6
|
Miyoshi Y, Nishimura T, Shimojo Y, Okayama K, Awazu K. Endoscopic image-guided laser treatment system based on fiber bundle laser steering. Sci Rep 2023; 13:2921. [PMID: 36854756 PMCID: PMC9975189 DOI: 10.1038/s41598-023-29392-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/03/2023] [Indexed: 03/02/2023] Open
Abstract
A miniaturized endoscopic laser system with laser steering has great potential to expand the application of minimally invasive laser treatment for micro-lesions inside narrow organs. The conventional systems require separate optical paths for endoscopic imaging and laser steering, which limits their application inside narrower organs. Herein, we present a novel endoscopic image-guided laser treatment system with a thin tip that can access inside narrow organs. The system uses a single fiber bundle to simultaneously acquire endoscopic images and modulate the laser-irradiated area. The insertion and operation of the system in a narrow space were demonstrated using an artificial vascular model. Repeated laser steering along set targets demonstrated accurate laser irradiation within a root-mean-square error of 28 [Formula: see text]m, and static repeatability such that the laser irradiation position was controlled within a 12 [Formula: see text]m radius of dispersion about the mean trajectory. Unexpected irradiation on the distal irradiated plane due to fiber bundle crosstalk was reduced by selecting the appropriate laser input diameter. The laser steering trajectory spatially controlled the photothermal effects, vaporization, and coagulation of chicken liver tissue. This novel system achieves minimally invasive endoscopic laser treatment with high lesion-selectivity in narrow organs, such as the peripheral lung and coronary arteries.
Collapse
Affiliation(s)
- Yuto Miyoshi
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
| | - Takahiro Nishimura
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
| | - Yu Shimojo
- grid.136593.b0000 0004 0373 3971Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 Japan
| | - Keita Okayama
- grid.136593.b0000 0004 0373 3971Graduate School of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871 Japan ,grid.136593.b0000 0004 0373 3971Global Center for Medical Engineering and Informatics, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871 Japan
| | - Kunio Awazu
- grid.136593.b0000 0004 0373 3971Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 Japan ,grid.136593.b0000 0004 0373 3971Global Center for Medical Engineering and Informatics, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871 Japan
| |
Collapse
|
7
|
Shimojo Y, Nishimura T, Hazama H, Ito N, Awazu K. Incident Fluence Analysis for 755-nm Picosecond Laser Treatment of Pigmented Skin Lesions Based on Threshold Fluences for Melanosome Disruption. Lasers Surg Med 2021; 53:1096-1104. [PMID: 33604920 PMCID: PMC8519018 DOI: 10.1002/lsm.23391] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/25/2021] [Accepted: 02/01/2021] [Indexed: 11/24/2022]
Abstract
Background and Objectives In this study, the threshold fluences for disrupting the melanosomes for pigmented skin lesion treatment were determined using a 755‐nm picosecond laser for clinical use. Based on the melanosome disruption thresholds, incident fluences corresponding to the target lesion depths were evaluated in silico for different laser spot sizes. Study Design/Materials and Methods Melanosome samples were isolated from porcine eyes as alternative samples for human cutaneous melanosomes. The isolated melanosomes were exposed to 755‐nm picosecond laser pulses to measure the mean particle sizes by dynamic light scattering and confirm their disruption by scanning electron microscopy. The threshold fluences were statistically determined from the relationships between the irradiated fluences and the mean particle sizes. Incident fluences of picosecond laser pulses for the disruption of melanosomes located at different depths in skin tissue were calculated through a light transport simulation using the obtained thresholds. Results The threshold fluences of 550‐ and 750‐picosecond laser pulses were determined to be 2.19 and 2.49 J/cm2, respectively. The numerical simulation indicated that appropriate incident fluences of picosecond laser pulses differ depending on the depth distribution of the melanosomes in the skin tissue, and large spot sizes are desirable for disrupting the melanosomes more deeply located within the skin tissue. Conclusion The threshold fluences of picosecond laser pulses for melanosome disruption were determined. The incident fluence analysis based on the thresholds for melanosome disruption provides valuable information for the selection of irradiation endpoints for picosecond laser treatment of pigmented skin lesions. Lasers Surg. Med. © 2021 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC
Collapse
Affiliation(s)
- Yu Shimojo
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Takahiro Nishimura
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Hisanao Hazama
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Nobuhisa Ito
- Global Center for Medical Engineering and Informatics, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan
| | - Kunio Awazu
- Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.,Global Center for Medical Engineering and Informatics, Osaka University, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan.,Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
8
|
Shimojo Y, Nishimura T, Hazama H, Ozawa T, Awazu K. Measurement of absorption and reduced scattering coefficients in Asian human epidermis, dermis, and subcutaneous fat tissues in the 400- to 1100-nm wavelength range for optical penetration depth and energy deposition analysis (Errata). J Biomed Opt 2021; 26:JBO-21-1007. [PMID: 33480218 PMCID: PMC7819376 DOI: 10.1117/1.jbo.26.1.019802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Indexed: 06/12/2023]
Abstract
The errata correct errors that appeared in Table 2 of the published article.
Collapse
Affiliation(s)
- Yu Shimojo
- Osaka University, Graduate School of Engineering, Suita, Japan
| | | | - Hisanao Hazama
- Osaka University, Graduate School of Engineering, Suita, Japan
| | - Toshiyuki Ozawa
- Osaka City University, Graduate School of Medicine, Department of Dermatology, Osaka, Japan
| | - Kunio Awazu
- Osaka University, Graduate School of Engineering, Suita, Japan
- Osaka University, Graduate School of Frontier Biosciences, Suita, Japan
- Osaka University, Global Center for Medical Engineering and Informatics, Suita, Japan
| |
Collapse
|
9
|
Shimojo Y, Nishimura T, Hazama H, Ozawa T, Awazu K. Measurement of absorption and reduced scattering coefficients in Asian human epidermis, dermis, and subcutaneous fat tissues in the 400- to 1100-nm wavelength range for optical penetration depth and energy deposition analysis. J Biomed Opt 2020; 25:1-14. [PMID: 32356424 PMCID: PMC7191311 DOI: 10.1117/1.jbo.25.4.045002] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/20/2020] [Indexed: 05/02/2023]
Abstract
SIGNIFICANCE In laser therapy and diagnosis of skin diseases, the irradiated light distribution, which is determined by the absorption coefficient μa and reduced scattering coefficient μs' of the epidermis, dermis, and subcutaneous fat, affects the treatment outcome and diagnosis accuracy. Although values for μa and μs' have been reported, detailed analysis for Asian skin tissues is still lacking. AIM We present μa and μs' measurements of Asian skin tissues in the 400- to 1100-nm wavelength range for evaluating optical penetration depth and energy deposition. APPROACH The measurements with Asian human skin samples are performed employing a double integrating sphere spectrometric system and an inverse Monte Carlo technique. Using the measured parameters, the optical penetration depth and energy deposition are quantitatively analyzed. RESULTS The μa of the epidermis layer varies among different ethnic groups, while the μa of the other layers and the μs' of all of the layers exhibit almost no differences. The analysis reveals that the optical penetration depth and the energy deposition affect the photodynamic therapy treatment depth and the heat production in skin tissue, respectively. CONCLUSIONS The experimentally measured values of μa and μs' for Asian skin tissues are presented, and the light behavior in Asian skin tissues is analyzed using a layered tissue model.
Collapse
Affiliation(s)
- Yu Shimojo
- Osaka University, Graduate School of Engineering, Suita, Japan
- Address all correspondence to Yu Shimojo, E-mail: ; Takahiro Nishimura, E-mail:
| | - Takahiro Nishimura
- Osaka University, Graduate School of Engineering, Suita, Japan
- Address all correspondence to Yu Shimojo, E-mail: ; Takahiro Nishimura, E-mail:
| | - Hisanao Hazama
- Osaka University, Graduate School of Engineering, Suita, Japan
| | - Toshiyuki Ozawa
- Osaka City University, Graduate School of Medicine, Department of Dermatology, Osaka, Japan
| | - Kunio Awazu
- Osaka University, Graduate School of Engineering, Suita, Japan
- Osaka University, Graduate School of Frontier Biosciences, Suita, Japan
- Osaka University, Global Center for Medical Engineering and Informatics, Suita, Japan
| |
Collapse
|
10
|
Shimojo Y, Nishimura T, Hazama H, Ito N, Awazu K. Picosecond Laser-Induced Photothermal Skin Damage Evaluation by Computational Clinical Trial. Laser Ther 2020; 29:61-72. [PMID: 32903975 DOI: 10.5978/islsm.20-or-08] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 04/23/2020] [Indexed: 01/07/2023]
Abstract
Background and Objectives Computational clinical trial (CCT) in the field of laser medicine promotes clinical application of novel laser devices, because this trial carried out based on numerical modeling of laser-tissue interactions and simulation of a series of treatment process. To confirm the feasibility of the computational clinical trial of skin treatment with a novel picosecond laser, this paper presents an evaluation method of the safety. Study Design/Materials and Methods In this method, the light propagation and thermal diffusion process after ultrashort light pulse irradiation to a numerical skin model is calculated and the safety based on the photothermal damage is evaluated by computational modeling and simulation. As an example, the safety of a novel picosecond laser device was examined by comparing with several laser devices approved for clinical use. Results The ratio of the maximum thermal damage induced by picosecond laser irradiation was 1.2 × 10-2 % at the epidermis, while that caused by approved laser irradiation was 99 % at the capillary vessels. The numerical simulation demonstrated that less thermal damage was observed compared with the approved devices. The results show the safety simulated by photothermal damage calculation was consistent with the reported clinical trials. Conclusions This computational clinical trial shows the feasibility of applying computational clinical trials for the safety evaluation of novel medical laser devices. In contrast to preclinical and clinical tests, the proposed computational method offers regulatory science for appropriately and quickly predicting and evaluating the safety of a novel laser device.
Collapse
Affiliation(s)
- Y Shimojo
- Graduate School of Engineering, Osaka University, Suita, Japan
| | - T Nishimura
- Graduate School of Engineering, Osaka University, Suita, Japan
| | - H Hazama
- Graduate School of Engineering, Osaka University, Suita, Japan
| | - N Ito
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Japan
| | - K Awazu
- Graduate School of Engineering, Osaka University, Suita, Japan.,Global Center for Medical Engineering and Informatics, Osaka University, Suita, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| |
Collapse
|
11
|
Yoshizawa S, Shimojo Y, Nakamura M, Kutsuzawa N, Kambe S, Ishii O. Remote Temperature Sensor Made of Magnetoelastic Ribbon. ACTA ACUST UNITED AC 2006. [DOI: 10.3379/jmsjmag.30.170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
12
|
Shimojo Y, Osawa Y, Fukumizu M, Hanaoka S, Tanaka H, Ogata F, Sasaki M, Sugai K. Severe infantile dentatorubral pallidoluysian atrophy with extreme expansion of CAG repeats. Neurology 2001; 56:277-8. [PMID: 11160976 DOI: 10.1212/wnl.56.2.277] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Y Shimojo
- Department of Child Neurology, National Center Hospital for Mental, Nervous, and Muscular Disorders, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
13
|
|