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Lasers and New Technologies in Hair Diseases
Published in Rubina Alves, Ramon Grimalt, Techniques in the Evaluation and Management of Hair Diseases, 2021
Giselle Martins Pinto, Patricia Damasco
It has been long known that red and near-infrared laser light promotes tissue repair, regeneration, and stimulates cellular activity. Endre Mester, a Hungarian physician, in the late 1960s, discovered the biological effects of low-power lasers [1]. Mester had obtained an example of the newly invented ruby laser and commenced a series of experiments on the carcinogenic potential of lasers. However, the ruby laser did not have sufficient power to produce cures in an experimental tumor, Mester found that incisions that had been made healed more rapidly in the laser-treated animals than in controls, and the hair started to grow faster on the irradiated skin area compared to the nonirradiated skin [2]. He named this phenomenon “laser biostimulation” and it later became known as low-level laser therapy (LLLT) [2]. Other names have also been used, such as photobiomodulation, red light therapy, cold laser, and soft laser [3]. The use of the photobiomodulation (PBM) term to replace LLLT was considered in an international consensus for three reasons [4]. First, the words low and level are vague and not accurately definable. Second, the growing realization that other types of light devices such as light-emitting diodes (LEDs) and broadband light sources are currently used for this application. Third, the understanding that many of the applications involved inhibition of biological processes meant that the term modulation was more appropriate [4].
Microneedles vs. Other Transdermal Technologies
Published in Boris Stoeber, Raja K Sivamani, Howard I. Maibach, Microneedling in Clinical Practice, 2020
Yeakuty Jhanker, James H.N. Tran, Heather A.E. Benson, Tarl W. Prow
The absorption of laser energy is related to the optical absorbance of water within the skin; thus the choice of laser can be tailored to the depth of desired tissue ablation. A ruby laser has poor water absorbance at 694 nm resulting in a minimally ablative technique, while a CO2 laser is highly absorbed at 10,600 nm resulting in strong ablation but also more extensive photothermal tissue damage. Erbium:yttrium-gallium-garnet (Er:YAG) and yttrium scandium gallium garnet (YSGG) lasers, emitting at 2790 nm and 2940 nm respectively, offer effective ablation of the SC with reduced thermal damage to the underlying viable tissue (60).
Photobiomodulation Therapy in Orthopedics
Published in Kohlstadt Ingrid, Cintron Kenneth, Metabolic Therapies in Orthopedics, Second Edition, 2018
Photobiomodulation (PBM) also known as low-level laser (light) therapy (LLLT) is approaching its 50th anniversary [1]. LLLT was originally discovered by Endre Mester working in Hungary, who was trying to repeat an experiment described by Paul McGuff in Boston. McGuff had used the newly discovered ruby laser to cure experimental tumors implanted in Sy rian hamsters [2, 3]. However, Mester’s laser only had a small fraction of the power possessed by McGuff’s laser and was insufficient to cure any tumors. Nevertheless Mester observed that the skin wounds that had been made during implantation of the tumors healed better in laser treated animals [4, 5]. Since those early days, LLLT has become gradually more accepted in scientific, medical and popular circles, especially as the number of peer-reviewed papers has grown.
Laser ablation and topical drug delivery: a review of recent advances
Published in Expert Opinion on Drug Delivery, 2019
Chien-Yu Hsiao, Shih-Chun Yang, Ahmed Alalaiwe, Jia-You Fang
The term laser is an abbreviation of light amplification by stimulated emission of radiation. Laser is a modality producing an intense beam of coherent monochromatic radiation by photon emission stimulation from excited molecules or atoms. The first laser device was developed in 1955 by Dr. Theodore Maiman at Hughes Research Laboratories [7]. The first experience of employing laser for medicinal practice was the use of a ruby laser in tattoo removal by Dr. Leon Goldman [8]. Over the last few decades, lasers have largely been used in dermatology for treating wrinkling, photoaging, hyperpigmentation, actinic keratosis, and scars. The laser is also useful to treat cancers in the presence of photothermal effect. For instance, the near infrared laser in combination with photothermal agents can be applied to deliver anticancer drugs for tumor inhibition [9–11]. The concept of laser-assisted drug transport is based on the reversible ablation or disruption of skin by irradiation to increase skin absorption of the drugs and allow deeper penetration. The first approval of laser-assisted skin delivery was reported by Jacques et al. in 1987 [12]. In that paper, an excimer laser (193 nm) was used to ablate SC from in vitro human skin. The laser fluence at 70 mJ/cm2 produced a 124-fold enhancement of tritiated water permeation, which is similar to that obtained after SC stripping or epidermal removal by mild heat treatment. Since then, some research groups put their efforts into studying drug absorption enhancement by a variety of laser modalities.
Laser-assisted hair removal for facial hirsutism in women: A review of evidence
Published in Journal of Cosmetic and Laser Therapy, 2018
Judging by the chromophore’s absorption co-efficient alone (Figure 1), the frequency-doubled 532 nm Nd:YAG lasers would have been the perfect choice to target follicular melanin in an over-simplified principle, but hair follicles are buried in the dermis, protected by the scatter of light, and the competing melanin in the epidermis, within the hair shaft and outer root sheath could reduce the effective fluence on the hair follicle and attenuate selective damage. It follows that laser hair removal has to utilize more than the theory of selective photothermolysis, originally coined by Anderson and Parish in 1983 (4). The effect of one single treatment with 0.27 ms, 694 nm ruby laser in 13 individuals has been described in a small, prospective observational study (6). In the study hair growth delay was apparent in all 13 study subjects with a reduction in terminal to vellus-like hair ratio in the treatment group.
Treatment of linear and whorled nevoid hypermelanosis using QS 694-nm ruby laser
Published in Journal of Cosmetic and Laser Therapy, 2022
Zhengzhou Shi, Xilei Duan, Min Jiang, Chengfeng Zhang, Leihong Xiang
Laser therapy has been proven safe and effective for the treatment of pigmented lesions. Given its minimally invasive nature and high efficacy, it has begun to gain ground as a therapeutic option for patients with these lesions (2). The main therapeutic mechanism of lasers relies on the emitted light, which is specifically and adequately absorbed by the target chromophores, resulting in melanin removal (6). Laser light using high energy that is adequately absorbed by melanin is available at multiple wavelengths, including ruby laser (694 nm), alexandrite laser (755 nm), and Nd:YAG laser (532 and 1064 nm). QS lasers have been used to successfully treat pigmented lesions such as unwanted tattoos, pigmented nevi, freckles, and café-au-lait macules. There is a relative paucity of published data using such lasers to treat LWNH. Catherine et al. reported a series of LWNH lesions treated with QS 532-, 755-, and 1064-nm lasers (3). Although the QS 1064-nm laser did not provide any improvement, both the 532- and 755-nm lasers were effective in one to two sessions. To date, QS 694-nm ruby laser has never been reported in treating LWNH. One principle to consider when choosing a laser for medical therapy is that the penetration depth of a laser is inversely proportional to the wavelength (7). Because the RCM of our patient revealed increased pigmentation of the epidermis and upper dermis, QS 694-nm ruby laser, with a good treatment depth and melanin absorption, might be the ideal laser to treat pigmented lesions. Interestingly, we observed that the treatment response of LWNH was exceptionally high even after a single treatment course.