scholarly journals The Thermal Damage of Canine Vocal Fold by CO2 Laser Under Different Laser Emission Mode

2021 ◽  
pp. 014556132199926
Author(s):  
Xumao Li ◽  
Jiaying Li ◽  
Xidong Cui ◽  
Xinqi Hu ◽  
Pengcheng Yu ◽  
...  
Keyword(s):  
Laser Power ◽  
Vocal Fold ◽  
Thermal Damage ◽  
Laser Emission ◽  
Continuous Wave ◽  
Beagle Dogs ◽  
Coagulative Necrosis ◽  
Hydropic Degeneration ◽  
Damage Area ◽  
Emission Mode

Objective: The purpose of this study is to review the differences between continuous wave (CW) and UltraPulse (UP) on thermal damage of the laser with different power. Methods: Four adult beagle dogs underwent transoral laser microsurgery (TLM) using CO2 laser. The laser emission mode and power was CW (3 W, 5 W, and 8 W) and UP (3 W and 5 W), respectively. The tissue from 4 animals was evaluated histologically on postoperative days 1 and 3. The thermal damage of the laser was measured using slide scan system via SlideViewer version 1.5.5.2 software. Results: All dogs underwent TLM uneventfully. Under microscope examined, the laser damage area was composed of 2 parts: the vaporized zone (VPZ) and thermal damage area. The thermal damage area can be divided into thermal coagulative necrosis area (TCN) and hydropic degeneration area. The width of VPZ and TCN in UP mode was less than that in CW mode ( P < .01). The data indicate that lower laser power created less thermal damage ( P < .01). In addition, the width of VPZ on postoperative day 3 was less than that on postoperative day 1 ( P < .01). Conclusion: CO2 laser with UP and lower power could decrease the laser thermal damage and may offer more prompt wound healing.

An in vitro comparison of the erbium: YAG laser and the carbon dioxide laser in laryngeal surgery

1993 ◽  
Vol 107 (10) ◽  
pp. 908-911 ◽  
Author(s):  
Rory C. D. Herdman ◽  
Andrew Charlton ◽  
Anthony E. Hinton ◽  
Anthony J. Freemont
Keyword(s):  
Carbon Dioxide ◽  
Co2 Laser ◽  
Vocal Fold ◽  
Carbon Dioxide Laser ◽  
Thermal Damage ◽  
Coagulative Necrosis ◽  
Yag Laser ◽  
Laryngeal Surgery ◽  
In Vitro Comparison

AbstractThis study compares the relative thermal damage caused by a surgical CO2 laser and the Erbium: YAG laser when used to incise the human vocal fold in vitro. Results show that charring is completely eliminated when using the Erbium: YAG laser. The depth of coagulative necrosis adjacent to an incision is reduced from 510 ±m(µ 75) using the CO2 laser to 23 ±m(µ 12) using the Ebrium: YAG laser and at the base is reduced from 125 ±m (µ 45) using the CO2 laser to 12 ±m (µ 8 ) using the Erbium: YAG laser. The potential advantages regarding post-operative healing after laryngeal surgery are discussed.

LD-pumped high-power continuous-wave Pr3+:YLF deep red lasers at 718.5 and 720.8 nm

Laser Physics ◽  
2021 ◽  
Vol 32 (2) ◽  
pp. 025801
Author(s):  
Xiangrui Liu ◽  
Zhuang Li ◽  
Chengkun Shi ◽  
Bo Xiao ◽  
Run Fang ◽  
...  
Keyword(s):  
Output Power ◽  
High Power ◽  
Slope Efficiency ◽  
Laser Emission ◽  
Continuous Wave ◽  
Optical Glass ◽  
Maximum Output Power ◽  
Glass Plate ◽  
Maximum Output ◽  
First Time

Abstract We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF 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.

Removal of Large Foreign Bodies Made of Thermoplastic Material from the Eye

2017 ◽  
Vol 27 (5) ◽  
pp. 621-625
Author(s):  
Georgiy Stolyarenko ◽  
Dzhasser Doroshenko ◽  
Victor Salakhutdinov ◽  
Yuri Smetanin
Keyword(s):  
Polyethylene Terephthalate ◽  
Laser Power ◽  
Foreign Bodies ◽  
Laser Emission ◽  
Ball Bearing ◽  
Main Idea ◽  
Thermoplastic Material ◽  
Laser Probe ◽  
Scattering Effects ◽  
Multiple Scattering Effects

Purpose To present the results of research aimed at developing a new method of minimally invasive removal of an intraocular foreign body (IOFB) from the eye cavity. Methods The main idea was to fix the IOFB onto the edge of a laser probe, which is transsclerally injected into the eye. After that, the IOFB is fixed at the end of the laser probe and removed transpupillary from the eye through an incision in the cornea. In order to fix the IOFB on the laser probe edge, this edge should be brought closely to the IOFB surface. The material of the IOFB should be locally fused using the laser emission. During this process, the probe edge should be submerged into the liquid melt. After laser emission is turned off, the material around the probe is hardened and the IOFB is hardly fixed on the laser probe edge. Results and Conclusions The main laser emission parameters and their influence on the eye tissue were investigated within a thermodynamic model. It is shown that for IOFB made from polyethylene terephthalate the optimal laser power is close to 2 W, the rate of rise of light energy is more than 10 ms, and the wavelength is approximately 0.905 μm. With these parameters (taking into account multiple scattering effects), the light impact on the retina will not exceed 100 mW/cm2, which is not dangerous for eye tissue. Efficiency is supported by clinical testing. The method was used for intraocular extraction of an Airsoft ball bearing (6 mm sphere of polyethylene terephthalate). The overall extraction time was approximately 4 minutes.

Over 1.3μm continuous-wave laser emission from InGaSb quantum-dot laser diode fabricated on GaAs substrates

2005 ◽  
Vol 86 (20) ◽  
pp. 203118 ◽  
Author(s):  
Naokatsu Yamamoto ◽  
Kouichi Akahane ◽  
Shinichirou Gozu ◽  
Naoki Ohtani
Keyword(s):  
Quantum Dot ◽  
Laser Diode ◽  
Laser Emission ◽  
Continuous Wave ◽  
Continuous Wave Laser ◽  
Gaas Substrates ◽  
Quantum Dot Laser ◽  
Wave Laser

scholarly journals Synchronized Optical and Acoustic Droplet Vaporization for Effective Sonoporation

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 279 ◽  
Author(s):  
Wei-Wen Liu ◽  
Sy-Han Huang ◽  
Pai-Chi Li
Keyword(s):  
Laser Power ◽  
Continuous Wave ◽  
Synergistic Effects ◽  
Tumor Therapy ◽  
Average Power ◽  
Acoustic Droplet Vaporization ◽  
Droplet Vaporization ◽  
Inertial Cavitation ◽  
Cw Laser ◽  
Ultrasound Pulse

Inertial cavitation-based sonoporation has been utilized to enhance treatment delivery efficacy. In our previous study, we demonstrated that tumor therapeutic efficacy can be enhanced through vaporization-assisted sonoporation with gold nanodroplets (AuNDs). Specifically, the AuNDs were vaporized both acoustically (i.e., acoustic droplet vaporization, ADV) and optically (i.e., optical droplet vaporization, ODV). A continuous wave (CW) laser was used for ODV in combination with an ultrasound pulse for ADV. Although effective for vaporization, the use of a CW laser is not energy efficient and may create unwanted heating and concomitant tissue damage. In this study, we propose the use of a pulsed wave (PW) laser to replace the CW laser. In addition, the PW laser was applied at the rarefaction phase of the ultrasound pulse so that the synergistic effects of ADV and ODV can be expected. Therefore, a significantly lower laser average power can be expected to achieve the vaporization threshold. Compared to the CW laser power at 2 W/cm2 from the previous approach, the PW laser power was reduced to only 0.2404 W/cm2. Furthermore, we also demonstrate in vitro that the sonoporation rate was increased when the PW laser was applied at the rarefaction phase. Specifically, the vaporization signal, the inertial cavitation signal, and the sonoporation rate all displayed a 1-µs period, which corresponded to the period of the 1-MHz acoustic wave used for ADV, as a function of the relative laser delay. The increased sonoporation rate indicates that this technique has the potential to enhance sonoporation-directed drug delivery and tumor therapy with a lower laser power while keeping the cell death rate at the minimum. Photoacoustic imaging can also be performed at the same time since a PW laser is used for the ODV.

Laser Sintering of Aerosol Jet Printed Interconnects on Flexible Substrate

2019 ◽  
Vol 2019 (1) ◽  
pp. 000404-000408 ◽  
Author(s):  
Mohammed Alhendi ◽  
Ludovico Cestarollo ◽  
Gurvinder S. Khinda ◽  
Darshana L. Weerawarne ◽  
Mark D. Poliks
Keyword(s):  
Laser Power ◽  
Continuous Wave ◽  
Flexible Substrate ◽  
Statistical Design ◽  
Laser Sintering ◽  
Continuous Wave Laser ◽  
Convection Oven ◽  
Wave Laser ◽  
Nanoparticle Ink ◽  
Full Factorial

Abstract Laser sintering of interconnects printed on flexible substrate with silver nanoparticle ink is studied as an alternative to convection oven sintering. Interconnects of 80 μm and 250 μm line width are printed using an aerosol jet printer and sintered using an 830 nm continuous wave laser. A conductivity that is 4.5× higher than that of an oven sintered interconnect is achieved at optimal laser power and sintering speed set using a full factorial statistical design.

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