Reduction in lateral thermal damage using heat-conducting templates: A comparison of continuous wave and pulsed CO2 lasers

2003 ◽  
Vol 32 (2) ◽  
pp. 94-100 ◽  
Author(s):  
Nicole Spector ◽  
Jared Spector ◽  
Darrel L. Ellis ◽  
Lou Reinisch
Keyword(s):  
Thermal Damage ◽  
Continuous Wave ◽  
Heat Conducting ◽  
Co2 Lasers

scholarly journals Threshold of permanent cornea thermal damage due to incidental continuous wave CO2 laser irradiation

2010 ◽  
Vol 14 (2) ◽  
pp. 459-467 ◽  
Author(s):  
Mayada Tahir
Keyword(s):  
Laser Irradiation ◽  
Co2 Laser ◽  
Thermal Damage ◽  
Continuous Wave ◽  
Anterior Part ◽  
Outer Part ◽  
Human Cornea ◽  
Thermal Dose ◽  
Element Analysis ◽  
Reflex Blink

Cornea thermal damage due to incidental continuous wave CO2 laser irradiation is studied numerically based on bio-heat equation. The interaction of laser with tissue leads to a rapid temperature increased in target and the nearby tissue. As the temperature of the eye surface reaches 44?C, a sensation of pain will cause aversion response of the reflex blink and/or shifting away from the source of pain. The aim of the work is to predict numerically the threshold limit of incidental laser power that causes damage to the anterior part of the cornea, which can be healed within 2-5 days as long as damage is not exceeding the outer part of the eye (epithelium). A finite element analysis is used to predict temperature distribution through the cornea where the necroses region can be obtained using thermal dose equation. The thermal dose that required for damaging the cornea is predicted from previously published experimental data on rhesus monkeys and used later as a limit for shrinkage to human cornea. The result of this work is compared by international standard of safety and a good nearby result is obtained which verified the result of this work.

scholarly journals Highlights of Thirty-Year Experience of Laser Use at the Florence (Italy) Department of Dermatology

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Piero Campolmi ◽  
Paolo Bonan ◽  
Giovanni Cannarozzo ◽  
Andrea Bassi ◽  
Nicola Bruscino ◽  
...  
Keyword(s):  
Gold Standard ◽  
Thermal Damage ◽  
Soft Tissues ◽  
Continuous Wave ◽  
Healing Time ◽  
Easy Access ◽  
Hypertrophic Scars ◽  
Cytologic Examination ◽  
The Past ◽  
Higher Power

The CO2laser has been used extensively in dermatological surgery over the past 30 years and is now recognised as the gold standard for soft tissue vaporization. Considering that the continuous wave CO2laser delivery system and the newer “superpulsed” and scanned CO2systems have progressively changed our practice and patient satisfaction, a long range documentation can be useful. Our experience has demonstrated that the use of CO2laser involves a reduced healing time, an infrequent need for anaesthesia, reduced thermal damage, less bleeding, less inflammation, the possibility of intra-operative histologic and/or cytologic examination, and easy access to anatomically difficult areas. Immediate side effects have been pain, erythema, edema, typically see with older methods, using higher power. The percentage of after-treatment keloids and hypertrophic scars observed was very low (~1%) especially upon the usage of lower parameters. The recurrence of viral lesions (condylomas and warts) have been not more frequent than those due to other techniques. Tumor recurrence is minor compared with radiotherapy or surgery. This method is a valid alternative to surgery and/or diathermocoagulation for microsurgery of soft tissues. Our results are at times not consistent with those published in the literature, stressing the concept that multicentric studies that harmonization methodology and the patient selection are vital.

Length reduction of tunable continuous wave CO2 lasers using Fabry-Perot resonators

1985 ◽  
Vol 43 (5) ◽  
pp. 1214-1217
Author(s):  
R. M. Abdullin ◽  
A. V. Lebedev ◽  
A. I. Popov
Keyword(s):  
Continuous Wave ◽  
Co2 Lasers ◽  
Fabry Perot ◽  
Length Reduction

scholarly journals Improving Plasmonic Photothermal Therapy of Lung Cancer Cells with Anti-EGFR Targeted Gold Nanorods

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1307 ◽  
Author(s):  
Oscar Knights ◽  
Steven Freear ◽  
James R. McLaughlan
Keyword(s):  
Lung Cancer ◽  
Minimally Invasive ◽  
Cancer Cells ◽  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Continuous Wave ◽  
Treatment Options ◽  
Lung Cancer Cells ◽  
Heat Conducting

Lung cancer is a particularly difficult form of cancer to diagnose and treat, due largely to the inaccessibility of tumours and the limited available treatment options. The development of plasmonic gold nanoparticles has led to their potential use in a large range of disciplines, and they have shown promise for applications in this area. The ability to functionalise these nanoparticles to target to specific cancer types, when combined with minimally invasive therapies such as photothermal therapy, could improve long-term outcomes for lung cancer patients. Conventionally, continuous wave lasers are used to generate bulk heating enhanced by gold nanorods that have accumulated in the target region. However, there are potential negative side-effects of heat-induced cell death, such as the risk of damage to healthy tissue due to heat conducting to the surrounding environment, and the development of heat and drug resistance. In this study, the use of pulsed lasers for photothermal therapy was investigated and compared with continuous wave lasers for gold nanorods with a surface plasmon resonance at 850 nm, which were functionalised with anti-EGFR antibodies. Photothermal therapy was performed with both laser systems, on lung cancer cells (A549) in vitro populations incubated with untargeted and targeted nanorods. It was shown that the combination of pulse wave laser illumination of targeted nanoparticles produced a reduction of 93 % ± 13 % in the cell viability compared with control exposures, which demonstrates a possible application for minimally invasive therapies for lung cancer.

Thermal damage mechanism of single junction GaAs solar cells irradiated by continuous wave laser

2018 ◽  
Vol 47 (5) ◽  
pp. 506001
Author(s):  
李云鹏 Li Yunpeng ◽  
张检民 Zhang Jianmin ◽  
窦鹏程 Dou Pengcheng ◽  
师宇斌 Shi Yubin ◽  
冯国斌 Feng Guobin
Keyword(s):  
Solar Cells ◽  
Thermal Damage ◽  
Continuous Wave ◽  
Damage Mechanism ◽  
Continuous Wave Laser ◽  
Single Junction ◽  
Wave Laser

DC-Excited Continuous-Wave Conventional and RF-Excited Waveguide CO2 Lasers

Gas Lasers ◽  
2018 ◽  
pp. 239-286
Author(s):  
F. Plinski Edward ◽  
M. Abramski Krzysztof
Keyword(s):  
Continuous Wave ◽  
Co2 Lasers ◽  
Waveguide Co2 Lasers

scholarly journals Histological Ex Vivo Evaluation of Peri-Incisional Thermal Effect Created by a New-Generation CO2Superpulsed Laser

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
G. Palaia ◽  
A. Del Vecchio ◽  
A. Impellizzeri ◽  
G. Tenore ◽  
P. Visca ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Connective Tissue ◽  
Thermal Damage ◽  
Histological Analysis ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Optical Microscope ◽  
Control Group ◽  
New Generation ◽  
Ex Vivo Study

The purpose of this study is the evaluation of the histological effects of a new-generation superpulsed CO2laser through an “ex vivo” study. A CO2(λ = 10,600 nm) ultra-speed laser (SmartUS20D, DEKA, Florence, Italy) has been used at different parameters from 2 to 4 watt in Continuous Wave (CW) and Pulsed Wave (PW, 50 Hz) to obtain 30 samples from pig cadaver tongues. All the specimens have been subdivided into 6 groups (from A to F) and each group consisted of 5 samples. A final specimen has been taken by scalpel and used as control group. Histological analysis has been performed using an optical microscope (Leica DM 2000) at a magnification of ×40. Results showed that histological readability was optimal in all the samples. The thermal damage has been negligible in all the groups. Furthermore, the average of thermal damage was 0,095 mm in the epithelial, while it was 0.245 mm in the connective tissue. Statistical analysis using Graphpad Prism 5 software showed no significant differences among the groups. CO2laser demonstrated a good surgical effectiveness provoking little peripheral damage onto the cut edges and allowing a safe histological diagnosis.

scholarly journals Histological Ex Vivo Evaluation of the Suitability of a 976 nm Diode Laser in Oral Soft Tissue Biopsies

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Gaspare Palaia ◽  
Federico Renzi ◽  
Daniele Pergolini ◽  
Alessandro Del Vecchio ◽  
Paolo Visca ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Soft Tissue ◽  
Diode Laser ◽  
Thermal Damage ◽  
Continuous Wave ◽  
Ex Vivo ◽  
Histological Evaluation ◽  
Epithelial Tissue ◽  
Medical Laser ◽  
Oral Soft Tissue

Introduction. Laser-induced thermal effects can preclude a safe histological evaluation of biopsy resection margins. The aim of this study was to evaluate the suitability of a 976 nm diode laser in oral soft tissue biopsies in an ex vivo study. Materials and Methods. A 976 nm diode laser (Solase®, Lazon Medical Laser, China) has been used in the contact mode, using a 400 μm fiber tip, at different parameters from 4 to 6 W in the continuous wave (CW), with a fluence between 3184 and 4777 J/cm2, and pulsed wave (PW) mode, with a fluence between 3184 and 4777 J/cm2, to obtain 30 samples from fresh pig cadaver tongues. All specimens were subdivided into 6 groups (from A to F), and each group consisted of 5 samples. Two sections were obtained from each sample. A histological analysis was performed using an optical microscope at magnifications of 5x and 10x. Statistical analysis was carried out using Kruskal–Wallis and Dunn’s tests. Results. The results showed that histological readability was optimal in all the samples. The thermal damage was negligible in all groups. The average thermal damage was 208.40 ± 133.81 μm in the epithelial tissue and 330.14 ± 147.45 μm in the connective tissue. The statistical analysis showed no differences between the groups ( p  > 0.05). Conclusion. A 976 nm diode laser demonstrated good surgical effectiveness that provoked little peripheral damage in the cut edges and allowed a safe histological diagnosis. Clinical Relevance. In oral pathology, many times, there is fear in using the laser to remove some lesions due to its thermal effect on the tissues close to the lesion. This effect is always present in the use of the laser, but the intent is to minimize this effect to have as little alteration as possible on the surrounding tissues.

Laser Sintering of Silver Nanomaterial on Polymer Substrates

2008 ◽  
Vol 5 (2) ◽  
pp. 77-86 ◽  
Author(s):  
Adeyl Khan ◽  
Nicholas Rasmussen ◽  
Valery Marinov ◽  
Orven F. Swenson
Keyword(s):  
Thermal Damage ◽  
Continuous Wave ◽  
Scanning Speed ◽  
Direct Write ◽  
Bulk Resistivity ◽  
Polymer Substrates ◽  
Fundamental Wavelength ◽  
Deposited Energy ◽  
Nanoparticle Ink ◽  
Better Than

Direct-write lines deposited on polyimide substrates using silver nanoparticle inks were laser-sintered and compared with similar samples sintered on a hot plate. The lines—30- to 60-μm wide, about 2.4 mm long, and less than a micrometer thick—were laser-sintered by scanning the fundamental wavelength of a continuous-wave Nd:YAG laser along the line. Deposited energy was varied by changing the laser power in addition to the scanning speed, and the resulting bulk resistivity was measured to determine the unsintered, transitional, sintered, and peel-off energy per volume of nanoparticle ink ranges. The bulk resistivity reported was comparable to or better than typical screen-printed conductors, and the elemental composition suggested no thermal damage of the substrate.

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