Numerical Modeling and Clinical Evaluation of Pulsed Dye Laser and Copper Vapor Laser in Skin Vascular Lesions Treatment

Introduction: Different yellow lasers have been successfully used for the treatment of vascular lesions. This study is aimed to ascertain the role and efficiency of copper vapor lasers (CVLs) and pulsed dye lasers (PDLs) for the treatment of vascular lesions using numerical modeling and to compare results with our clinical experience. In this study we aimed to develop criteria for the choice of more efficient laser exposure mode, investigate more relevant modes of laser irradiation to ensure selective photothermolysis of target vessels, and compare the CVL and PDL efficiency in the course of patients with skin vascular lesions (SVL) treatment.Methods: We performed numerical simulation of the processes of heating a vessel with CVL and PDL to temperatures at which its coagulation could occur. Calculated fluencies were compared with clinical results of laser therapy performed on 1242 patients with skin hemangiomas and vascular malformations (SHVM), including 635 patients treated with CVL and 607 patients treated with PDL. PDL and CVL provided excellent results in 40 and ten days after treatment. The treatment was not painful. Patients did not need anesthesia. Postoperative crusts were greater with PDL than with CVL.Results: Results of computer simulation of a selective vessel heating using PDL and CVL radiation are presented. By results obtained, depth of the location and sizes of vessels that could be selectively heated to more than 75°C are determined.Conclusion: Based on calculated and clinical data, the heating mode for dysplastic vessels using a series of CVL micropulses could be regarded to be safer and more efficient than the mode of a PDL short, powerful pulse

Electrospark method for obtaining nanopowders

In the paper, a metallic FexOy nanopowder was obtained by the electrospark method. The used electrospark installation consists of the electrode system, mobility system, system for measuring processing parameters (oscilloscope and current sensor, HV voltage divider, manovacuum meter), source of current pulses, vacuum system (vacuum pump, gas cylinders with working gas, gas routes, gas taps). The specific feature of the installation is the use of a power supply circuit of two generators with different voltage levels operating for one interelectrode gap. This generator circuit makes it possible to change the treatment parameters in wide ranges (pulse duration 10–100 ?s, pulse energy 0.1–0.6 J, pulse repetition rate 0.1–5 kHz). It will enable to choose the optimal ratio between the energy expended and the maximum yield of the product, as well as to study the influence of treatment parameters on the composition and properties of the resulting powder. The morphology and phase composition of the FexOy synthesized metal powder was studied

Treatment of Congenital Melanocytic Nevi With a Dual-Wavelengths Copper Vapor Laser: A Case Series

Introduction: Congenital melanocytic nevus (CMN) is a severe challenge for dermatology. This pigmented skin lesion is undesirable for patients because of its localization in open areas of the body. Various visible and near-infrared laser systems and intense pulsed light (IPL) sources have been applied for CMN treatment. However, post-traumatic hyperpigmentation, structural changes, atrophy, and scarring due to non-specific thermal damage have been observed. Many patients have shown recurrence after treatment. Therefore, it highlights the need for testing new laser modalities for the management of CMN.Methods: Two adult II Fitzpatrick phototype patients (a 55-year-old male and a 30-year-old female) with middle-sized facial CMN (on the forehead and lower eyelid) are presented. All patients were treated with dual-wavelength copper vapor laser (CVL) radiation at 511 nm and 578 nm wavelengths with a power ratio of 3:2. The average power was 0.7-0.85 W with an exposure time of 0.3 seconds. The spot size amounted to 1 mm.Results: Both patients showed complete resolution of CMN after CVL treatments. CMN became crusted within a few days after the laser treatment and peeled off within seven days. No recurrences were observed during the follow-up period up to 24 months.Conclusion: The middle-sized CMN can be successfully treated with dual-wavelength CVL radiation. DOI: 10.34172/jlms.2021.0

Numerical Modeling of The Dysplastic Vessel Heating in PWS by Yellow 578 nm Copper Vapor Laser Radiation for Different Skin Phototypes: Numerical modeling of the dysplastic vessel heating in PWS by yellow 578 nm CVL radiation for different skin phototypes

Background: This study aimed to develop the algorithm for choosing both effective and safe mode of dual-wavelengths copper vapor laser (CVL) photodestruction of dilated dermal vessels in PWS for different skin phototypes. This study is expected to assess the safe parameters for CVL treatment. Methods: We used the multilayered skin model with different melanin content for simulation. The calculation of the vascular component’s selective heating with CVL radiation at the green and yellow wavelengths for different skin phototypes was performed with Matlab mathematical programming system and its application Femlab for solving partial differential equations using the Finite element method. Results:   We determined the location depth and size of blood vessels that could be selectively heated to the coagulation temperature for different skin phototypes. Conclusion:   CVL can selectively heat 15-300 mcm vessel diameters that correspond to the PWS vessel diameter range. CVL fluence values need to be reduced almost twice for the IV skin phototype than the II skin phototype. The maximum depth of the vessels’ location also decreased for dark skin phototypes. Doi:10.34172/jlms.2022.1

Successful Treatment of Sebaceous Nevus With Copper Vapor Laser: Treatment of sebaceous nevus with copper vapor laser

Introduction: Sebaceous nevus (SN) is a benign skin hamartoma with a potent transformation into benign or malignant tumors in adolescents or adults. Due to the most common location in the esthetic zone, an SN makes patients seek a dermatologist for cosmetic concerns on the face or neck. The surgical excision of a large-sized SN in the esthetic zone may require reconstruction with a skin flap and be associated with recurrences and scar formation.Case Report: We describe the successful treatment of the large-sized neck SN with copper vapor laser (CVL) for the first time. A left-sided neck SN (linear size of 27 mm) in the 24-year-old Caucasian female completely resolved after eight CVL sessions. The settings were as follows: average power accounted for 0.8-1.0 W, with a ratio at green (511 nm) and yellow (578 nm) wavelengths of 3:2. The pulse duration was set as 20 nanoseconds, the repetition rate 16.6 kHz, the exposure time 200 ms, the light spot diameter of 1 mm. The CVL treatment resulted in the complete disappearance of the SN without remote side effects such as hyperpigmentation, scarring, or recurrences 24 months after the treatment. The patient was satisfied with the excellent cosmetic results.Conclusion: The CVL treatment of the SN provides the most relevant result due to the complete elimination of SN cells and the remodeling of the vascular bed supplying the involved areas

The Successful Treatment of Eyelid Intradermal Melanocytic Nevi (Nevus of Miescher)With the Dual-Wavelengths Copper Vapor Laser: Successful Treatment of Miescher Nevus With the Dual-Wavelengths CVL

Introduction: Surgical methods for removing eyelid nevus are associated with a risk of developing such side effects as scarring or loss of eyelashes. Although current laser modalities have shown promising results, eyelid laser surgery may cause skin discoloration and noticeable scarring. This study aims at evaluating the efficacy and safety of the dual-wavelengths copper vapor laser (CVL) treatment of eyelid intradermal nevus of Miescher (NM).Patients and Methods: We present three adult female patients with eyelid intradermal nevus treated with CVL. CVL settings were as follows: the average power of 0.6-0.8 W, under a power ratio of 3:2 at wavelengths of 511 nm and 578 nm, exposure time of 0.3 seconds, the light spot diameter of 1 mm.Results: The dual-wavelength CVL treatment of medium- and large-sized NM provides the complete removal of eyelid dome-like NM after one and two sessions with a month interval correspondingly. The duration of skin healing accounted for two weeks.Conclusion: The complete removal of eyelid NM lesions without side effects demonstrates the safety and efficacy of dual-wavelengths CVL in treating such skin lesions. This laser treatment mode of benign skin neoplasms seems promising for dermatologists and cosmetologists’ clinical practice.   DOI: 10.34172/jlms.2021.2