Q-switched Ruby Laser Research Articles

Infmorbital Pigmented Skin

The presence of infraobital dark skin, often known as dark circles under the eyes, is a frequent cosmetic concern. There has been little reported on therapy of this condition. One group of patients was determined to have dermal melanin deposition, which we treated with a Q-switched ruby laser. Our study evaluated the clinical and histological appearance of infraobital skin pigment in 17 patients with dermal melanin deposition treated with a Q-switched ruby laser. Seventeen patients with melanin deposition were treated with the Q-switched ruby laser (694 nm) with a pulse width of 28 nanoseconds and fluences of 7.5 J/cm2. Response to treatment was assessed by an independent investigator with patient and photograph evaluation. Skin Biopsies were obtained in nine of the 17 patients. Of those patients treated with one Q-switched ruby session, 23.5% achieved a greater than 50% response. Of those treated twice, 88.9% achieved greater than 50% response. In postreatment skin biopsies there was reduction of dermal melanin deposition. Patients with infraobital pigmented skin due to dermal melanin deposition may be considered candidates for Q-switched Ruby laser treatment.

Q-Switched Ruby Laser Treatment of Congenital Nevi

The Q-switched ruby laser has been used to treat a number of cutaneous lesions, including lentigines, 1 tattoos, and nevus of Ota. 2 The Q-switched ruby laser emits visible red light with a wave-length of 694 nm and pulse duration of 28 to 40 nanoseconds. This relatively long wavelength and short pulse duration allow for the absorption of laser energy into the dermis with minimal textural changes. Laser energy is selectively absorbed by both keratinocytes and melanocytes containing melanosomes. Although melanin in these melanosomes has an absorption spectrum that is highest in the UV range, diminishing toward the infrared range, there is minimal competitive absorption of ruby energy (694 nm) by oxyhemoglobin. 3 Management of congenital nevi has been the subject of much debate over the past decade. This stems from the unresolved controversy concerning their potential for malignant degeneration, specifically to malignant melanoma. We report on the use

Q-switched ruby laser treatment of congenital nevi

Q-switched ruby laser treatment of congenital nevi

The M-shell photoabsorption spectrum of Ge2+

The dual laser produced plasma (DLP) technique, has been used to study the EUV absorption spectra of germanium plasmas in the 50-400 AA region. The absorbing plasmas were produced by focusing the output of a Q-switched ruby laser onto a germanium target while the background continuum was produced by focusing the output of a Nd:YAG oscillator/amplifier system onto a samarium target. At a time delay of 50 ns and an absorbing plasma column length of 2 mm the spectrum recorded was predominantly due to Ge2+. We have investigated 3d and 3p sub-valence transitions. In the former, 3d104s2 to 3d94s2nf and 3d94s2np series converging on the 2D5/2 and 2D3/2 limits of Ge3+ were identified by isoelectronic comparison and Hartree-Fock calculations. In the 3p case no strong line transitions were observed which was shown by many body calculations to result from line broadening caused primarily by super Coster-Kronig decay of the 3p hole.

Treatment of blue nevi with the Q-switched ruby laser

The common blue nevus is a benign, localized collection of dermal melanocytes. To date, removal required excisional surgery to eliminate pigment that usually extends into the reticular dermis. We report the successful long-term elimination of common blue nevi on the nasal skin of two patients whose lesions were treated with the laser emission of 694 nm energy from the Q-switched ruby laser.

Q-Switched Ruby Laser for Nevus of Ota

There have been several brief reports of the effectiveness of the Q-switched ruby laser in treating nevus of Ota. While nevus of Ota is rare in Caucasians, it is of greater significance for the Japanese, in whom its prevalence is approximately 1 in 200 people. In this study from Japan, the largest to date, investigators treated 114 patients with nevi of Ota with a Q-switched ruby laser (wavelength 694 nm, pulse …

Q スイッチルビーレーザーによる真皮メラノサイトーシスの治療効果

Q スイッチルビーレーザーによる真皮メラノサイトーシスの治療効果

Q-Switched ruby laser for the treatment of pigmented lesions and tattoos

Q-Switched ruby laser for the treatment of pigmented lesions and tattoos

Q-switched ルビーレーザーを用いた太田母斑に対する治療法についての検討

Q-switched ルビーレーザーを用いた太田母斑に対する治療法についての検討

深在性太田母斑に対するQスイッチヤグレーザー照射とQスイッチルビーレーザー照射の比較検討

Lasers have attracted close attention among the currently available methods for their potential capacity to produce little discomfort, minimize scarring, and require few skills. There have not, however, been any laser systems with the efficacy to treat“true”deep seated dermal melanin pigmentation lesions as deep, deep dominant, and diffuse types of Ota's nevus. Recent reports have suggested use of the Q-switched ruby laser (Q-Ruby) and the Q-switched Nd: YAG laser (Q-YAG) achieved success in treating nevi. The effectiveness of these two laser systems against“deep seated”Ota's nevus has yet to be definitely determined in clinico-pathological observations.The authors evaluate the efficacy of the Q-YAG and the Q-Ruby against the“deep seated”Ota's nevus, comparing the effectiveness of the two laser systems both clinically and histopathologically.A total of 42 deep-seated Ota's nevus lesions of 20 patients were treated. Prior to treatment, all lesions were confirmed as the deep seated group of Ota's nevus, that is, one of the deep (De), deep dominant (DD), or diffuse (Di) types by skin biopsy. Q-YAG laser (NIIC: IS201, and Con-Bio: Medlite) having a wavelength of 1064nm and a pulse width of 10 nsec, and Q-Ruby laser (Spectrum: RD-1200) having a wavelength of 694nm and a pulse width of 25 nsec were used in the trials. Laser irradiation was conducted under local or general anesthesia. Each irradiation of Q-YAG and Q-Ruby was separately performed only one time at the same lesion of the same patient. The fluences used were between 7.0 and 8.0 J/cm2. After laser irradiation, biopsies were chronologically performed for both photo- and electron-microscope observation of post-irradiation change. The clinical effectiveness of Q-YAG and Q-Ruby at each treated site was judged over a period of three months after irradiation.The total effective rates of Q-YAG and Q-Ruby on deep-seated Ota's nevus were 41% and 33% respectively. Although there was no significant difference between Q-YAG and Q-Ruby in their respective effective rate according to lesional sites, there was prominent difference between the two lasers in histological effectiveness; on Type DD, the effective rates of Q-YAG and Q-Ruby were 38% and 13% respectively, and on Type De, they were 20% and 10% respectively. This difference was more prominent in such thick skin lesions as cheek and temple than in eyelid. The aforementioned more favorable results produced by Q-YAG than by Q-Ruby are thought attributable, not to 694nm wavelength ·dependent melanin-selective advantage of Q-Ruby, but to 1064nm wavelength-dependent penetration advantage of Q-YAG; the healing clearance of pigmentation at the deep dermal layer in deep-seated Ota's nevus depends more strongly on the ability of lesional penetration than on that of lesional selectivity.

Commentary

Tattoos result from exogenous material implanted in the dermis most often by tattoo artists, cosmetologists, or trauma. Placement of decorative tattoos is on the rise, with over 10 million people sporting at least one tattoo, and cosmetic tattoos such as eye, eyebrow, and lip liners are more popular than ever. In addition, tattoos are placed for identification of people (prisoners of war, gang members) and location (radiation port sites). Whatever the reason for initial placement, many then wish to have their tattoos removed.8 Prior to the advent of laser technology, most tattoos were removed by surgical excision, abrasive techniques, cryosurgery, or chemical peels.41 Unfortunately, violation of the dermis often left an equally undesirable scar.The first medical use of lasers was pioneered by Goldman in the early 1960s.20, 21, 22 He explored normal mode and Q-switched ruby laser light (694 nm) as a potential treatment modality for nevi and tattoos. Although Goldman's work suggested that the ruby laser could remove dermal pigment with little scarring, technical difficulties inhibited further exploration until its resurgence nearly 20 years later. Soon to follow the initial ruby laser studies were those on continuous wave CO2 and argon lasers.7, 12 The CO2 laser (10,600 nm) has a wavelength well absorbed by water, and the blue-green light of the argon laser (488–514 nm) is selective for melanin and hemoglobin. Both lasers have long exposure times, allowing heat to dissipate into the surrounding tissue and causing nonselective thermal injury, frequently resulting in dyspigmentation and scarring.In the early 1980s, Anderson and Parrish described the principle of selective photothermolysis,6 now employed in the development of most currently used lasers. Selective photothermolysis is the process of selectively destroying a target through heat generated by light. The laser light must be a wavelength absorbed by the targeted ink and preferably ignored by the surrounding chromophores, melanin, and hemoglobin.43 The exposure time must be limited, so that heat generated by the laser–tissue interaction is confined to the target itself.47 Finally, sufficient energy must be delivered to cause the desired effect. Rapidly pulsed lasers were produced to create these ultrashort bursts of light for treatment of pigment-containing lesions. Current Q-switched lasers have pulse durations in the nanosecond domain, wavelengths well absorbed by most tattoo inks, and very high peak powers, satisfying the criteria for selective photothermolysis of ink particles.6, 50 These ultrashort pulse durations may elicit a separate photoacoustic effect as well.30 Table 1 lists the Q-switched lasers and their properties.

Treatment of Nevus of Ota with the Q-Switched Ruby Laser

Nevus of Ota is a benign bluish or gray-brown lesion of the eye and the surrounding skin that has been reported to occur in about 1 in 200 people in Japan. Prior treatments have either been ineffective or caused scarring. The Q-switched ruby laser can produce very short high-energy pulses and can selectively target cells that contain pigment, such as dermal melanocytes. We treated the skin lesions of 114 patients (25 male and 89 female) with nevi of Ota with a Q-switched ruby laser set to deliver pulses of 6 J per square centimeter of body-surface area at a wavelength of 694.3 nm, with a pulse duration of 30 nanoseconds. The interval between treatments ranged from three to four months. Five dermatologists who were not familiar with the patients independently compared a full set of pretreatment and post-treatment photographs of each patient and determined the percentage of pigment lightening of the affected areas using standard criteria. Of the 35 patients who received four or five treatments, 33 had an excellent response (lightening of 70 percent or more), and 2 had a good response (lightening of 40 to 69 percent). Of the 31 patients who received three treatments, 4 had an excellent response, 26 a good response, and 1 a fair response (lightening of 10 to 39 percent). Of the 25 patients who received two treatments, 2 had an excellent response, 16 a good response, and 7 a fair response. Of the 23 patients who received one treatment, 3 had a good response, 13 a fair response, and 7 no response (lightening of 9 percent or less). No patient had hypertrophic or atrophic scarring; eight patients had postinflammatory hyperpigmentation for up to two months after the first treatment. Selective photothermolysis with the Q-switched ruby laser is a safe and effective method for lightening nevi of Ota. Multiple treatments increase the response rate.

The Removal of Cutaneous Pigmented Lesions with the Q‐switched Ruby Laser and the Q‐switched Neodymium: Yttrium‐Aluminum‐Garnet Laser

The Q-switched ruby laser (QSRL) (694 nm) has been used successfully in the removal of tattoos and a variety of cutaneous pigmented lesions. The frequency-doubled Q-switched neodymium:yttrium-aluminum-garnet laser (QSNd:YAG) (1064 and 532 nm) has also been shown to be effective in the treatment of tattoos, however, little has been published regarding the QSNd:YAG laser in the removal of cutaneous pigmented lesions. The purpose of this study is to compare the efficacy and side effect profile of the QSRL and the frequency-doubled QSNd:YAG lasers in the removal of cutaneous pigmented lesions, including lentigines, café-au-lait macules, nevus of Ota, nevus spilus, Becker's nevus, postinflammatory hyperpigmentation, and melasma. Twenty patients with pigmented lesions were treated with the QSRL and the frequency-doubled QSNd:YAG lasers. Clinical lightening of the lesion was assessed 1 month after a single treatment. Side effects and patient satisfaction were also evaluated. A minimum of 30% lightening was achieved in all patients after only one treatment with either the QSRL or the frequency-doubled QSNd:YAG laser. The QSRL seems to provide a slightly better treatment response than the QSNd:YAG laser. Neither laser caused scarring or textural change of the skin. Most patients found the QSRL to be more painful during treatment, but the QSNd:YAG laser caused more postoperative discomfort. Both the QSRL and the frequency-doubled QSND:YAG laser are safe and effective methods of treatment of epidermal and dermal pigmented lesions.

Q‐switched Ruby Laser Treatment of Labial Lentigines in Peutz‐Jeghers Syndrome

BACKGROUND. The Q-switched ruby laser emits energy with a 694-nm wavelength and has a pulse duration in the nanosecond range, which allows selective treatment of benign pigmented lesions. Labial and perioral pigmented macules associated with Peutz-Jeghers syndrome are often numerous and cosmetically disfiguring. RESULTS/CONCLUSION. We report successful treatment of these lentigines with the Q-switched ruby laser and consider it the treatment of choice for these lesions.

Low-field behavior of magnetic and transport properties of laser irradiated Nd-Ba-Cu-O ceramic superconductors

The low-field behavior of magnetic and transport properties of high-power laser-irradiated (Q-switched ruby laser, 694 nm, 30 ns) Nd-Ba-Cu-O (NBCO) ceramic superconductors prepared by the coprecipitation technique have been investigated. Laser-irradiated NBCO samples contribute significantly to the flux pinning for low applied magnetic fields. A well-defined field valueH′ c was observed for different laser-irradiated samples which is characteristic of a cross-over between regions dominated by the inter- and intragranular effects. The value ofH′ c for a laser-irradiated sample is increased with increasing number of laser pulses. Thermal modeling of laser heating reveals that on irradiation the surface melts up to a depth of 1μm and laser-induced evaporation occurs at energy density 2.5 J/cm2. SEM studies showed grain growth due to laser-induced surface sintering which improves the interconnectivity among the superconducting grain structure and thus attributed to physical densification and consequent reduction in the total number of weak links. The increase of flux trapping and transport critical current density after laser irradiation is determined by the rigidity of the flux line lattice which may be due to the presence of additional pinning centers caused by the creation of laser-induced mobile defects and their clusters.

Ineffective treatment of refractory melasma and postinflammatory hyperpigmentation by Q-switched ruby laser.

Melasma and postinflammatory pigmentation are cosmetic problems with limited options for treatment. To determine whether selective photothermolysis of pigmented cells by Q-switched ruby laser treatment would produce clinical benefit in these disorders. Eight subjects with melasma or postinflammatory hyperpigmentation refractory to traditional treatments were treated with Q-switched ruby laser pulses (694 nm, 40 nanoseconds) at fluences of 15-7.5 J/cm2, and followed. Histology was obtained before and after treatment. Regardless of fluence, no permanent improvement and, in some cases, darkening was seen in each type of lesion. Except for small depression at high fluences in black patients, there were no textural changes after healing. Immediately after treatment, there was epidermal and dermal injury, with extracellular melanin. Several months later, epidermal pigmentation had returned to baseline and dermal macrophages were apparently focally increased. The Q-switched ruby laser by itself does not provide an effective treatment for refractory melasma or postinflammatory hyperpigmentation.

Laser-induced compound formation and transfer of stacked elemental layers

A novel method is described for the effective mixing and transfer of compounds starting from stacked layers of the elements using single laser pulses in a characteristic fluence range. The potential of this technique is illustrated by a systematic study on the laser-induced transfer of germanium selenides from stacked layers of Ge and Se by a Q-switched ruby laser. The procedure offers a simple, single-step technology for surface patterning via local compound deposition.

Laser-generated rayleigh waves in graphite/epoxy composites

This study explores the potential for application of laser-induced surface or Rayleigh waves on graphite/epoxy composites. Rayleigh waves were generated by a Q-switched ruby laser in the ablation regime and detected by a pinducer which permitted accurate phase-velocity measurements. The Rayleigh wave velocity was measured in various directions relative to the fiber direction. Experimental results agreed closely with numerical predictions in the thick plate, but showed some increase of phase velocity in the thin plate. Laser-generated Rayleigh waves, particularly along the fiber direction, showed good potential for applications in NDT.

Treatment of nevus of Ota by Q-switched ruby laser

There are few reports on therapy for nevus of Ota. Moreover, traditional treatments are largely palliative or risk permanent pigmentary changes and/or scarring. The efficacy of the Q-switched ruby laser (694 nm, 40 nsec) as a therapy for nevus of Ota was investigated. Nine nevi or portions thereof were irradiated up to six times with 4.5 and/or 7.5 J/cm2 at a mean exposure interval of 3 weeks. Sequential skin biopsy specimens were processed for light microscopy, immunohistochemistry, and electron microscopy. Cosmetic improvement occurred at both doses in the irradiated parts of the six nevi available for follow-up. No appreciable difference was noted between single and multiple treatments. There was no gross scarring. Light microscopy revealed dose-related immediate injury with more melanophages and fewer dermal melanocytes after irradiation in comparison with control areas. Electron microscopic distinction between dermal melanocytes and melanin-laden macrophages was difficult. A monoclonal antibody to human melanosome-specific antigen type 1 (HMSA-1) was used to distinguish between the two cell populations. Our findings suggest that the Q-switched ruby laser is useful for treating nevus of Ota.

Q-switched ruby laser. Further observations on treatment of professional tattoos.

The Q-switched ruby laser is effective in the treatment of amateur tattoos and other pigmented lesions. Previous studies have shown that, though amateur tattoos usually respond well, professional tattoos show greater resistance to clearing. Our study evaluates the treatment of 20 patients with 28 professional (blue, green, black) tattoos by a Q-switched ruby laser with a 28-ns pulse width, and using high energy fluences up to 10 J/cm2. Responses proved to be good to excellent among these patients, who needed fewer treatments than previously reported.