Query: alexandrite

title: Characterization of the optically stimulated luminescence (OSL) response of beta irradiated alexandrite polymer composites
abstract: Alexandrite mineral (BeAl2O4:Cr3+ powder incorporated in a fluorinated polymer was prepared in the form of pellets. A mixture with 20 wt% of the alexandrite in the pellet had the luminescence behavior evaluated as a function of exposure to ionizing radiation using the optically stimulated luminescence (OSL) technique. The OSL measurements were evaluated in terms of dose response (beta dose from 0.1 to 5 Gy) repeatability, reproducibility, and fading. The results showed that the OSL intensity signal varied linearly with the irradiation dose and that the OSL intensity suffered a strong reduction during the first five days of storage in the dark but remained stable for at least the following 30 days. Radioluminescence (RL) measurements under X ray excitation revealed a weak luminescence within the ultraviolet visible spectral region, while optical absorption (OA) measurements revealed the presence of Cr3+ impurities.

title: Experimental investigations on thermal effects of a long pulse alexandrite laser on blood vessels and its comparison with pulsed dye and Nd:YAG lasers
abstract: Laser has been widely used in the treatment of vascular skin diseases, such as port wine stain, due to the effect of selective photothermolysis in laser on biological tissue. The 755 nm alexandrite laser was expected to achieve better curative effect than the commonly used 585 or 595 nm pulsed dye laser (PDL) because of its deeper tissue penetration. In this study, the dorsal chamber model and microscopic visualization system were used to observe morphology changes on 42 blood vessels before and after irradiation with the 755 nm laser. Results showed that thermal effects of blood vessels intensified with the increase in energy, and high energy was required to produce the same thermal effect as the extension of pulse width. Different from 595 and 1064 nm lasers, partial vessel contraction was dominant thermal effect caused by the 755 nm laser. The bleeding injury rate and thermal effect of the 755 nm laser were between those of 595 nm PDL and 1064 nm Nd:YAG laser. The simulation results proved that 595 nm PDLs were effective for small and shallow target blood vessels. The 755 nm alexandrite lasers were effective in the treatment of hypertrophic and resistant blood vessels to PDL in the skin with low or moderate melanin concentration. The 1064 nm Nd:YAG laser was effective in the treatment of deeply buried and enlarged target blood vessels in the skin with high melanin concentration. The simulation results were supported by published clinical observations.

title: Safety and efficacy of single pass vs multipass emission with 755 alexandrite laser for all skin type hair removal: A pilot study
abstract: Lasers are considered the most efficient methods for hair reduction. The goal of these devices is to provide long term effects without adverse reactions. This is a randomized split body controlled study on body hair removal and pseudofolliculitis (PFC) treatment, comparing the standard single pass (SP) emission with the multipass emission (Moveo handpiece) with 755 alexandrite laser. Patients with Fitzpatrick skin types I to VI underwent laser hair removal, by treating one side of the body using the standard SP and the other side with Moveo. Treated areas included face, arms, legs, trunk, axillae and groins. Each patient underwent a minimum of three to a maximum of eight treatments, every 6 weeks, with a 6 month follow up. Hair reduction, side effects, PFC severity score and patient satisfaction were recorded for all patients. Totally, 108 patients were enrolled, of whom 96 were female. The overall hair reduction rate SD) independent of skin type, was estimated as 87 5.5 for standard SP and 78.5 7.6 for Moveo. No significant statistically differences were found between the two groups. Side effects included pain, which was higher after standard SP (4.2 0.8) than after Moveo treatment (1.5 0.5) A statistical significant difference between the two devices was found (P .0002) PFC score improved in almost all the patients. Patients declared to be satisfied with both the treatments, reporting a preference for Moveo (84% vs 16% (P .01) Standard SP and Moveo 755 alexandrite laser seems to be safe and effective treatments for hair removal in all Fitzpatrick skin types and for PFC. Moveo has a higher security profile with fewer side effects.

title: Use of a Picosecond Alexandrite Laser for Treating Acquired Bilateral Nevus of Ota Like Macules in Chinese Patients
abstract: Acquired bilateral nevus of Ota like macules (ABNOM) is common among the Chinese population. There have been few studies on the use of a picosecond alexandrite laser for the treatment of ABNOMs. The goal of this study was to evaluate the efficacy and safety of a 755 nm picosecond alexandrite laser for the treatment of ABNOMs.

title: Observation on the effects of 595 nm pulsed dye laser and 755 nm long pulsed alexandrite laser on sequential therapy of infantile hemangioma
abstract: Infantile hemangioma (IH) can lead to severe complications. The 595 nm pulsed dye laser is poorly effective on thick and deep IH. Long pulsed alexandrite laser has the proper wavelength of 755 nm and a relatively deep penetration. Thus, this may be a safe and effective treatment method for relatively deep or thick IH.  This study aims to determine whether 595 nm pulsed dye laser and 755 nm long pulsed alexandrite laser in sequential therapy are safer and more effective for relatively deep or thick hemangioma.  This was a prospective study. A total of 194 infantile IH patients (thickness greater than 2 mm and less than 8 mm) were randomly divided into two groups: control group (treated using 595 nm pulsed dye laser) and experimental group (treated by sequential therapy with 755 nm long pulsed alexandrite laser and 595 nm dye laser)  The control group had a total effective rate of 36.1% while the experimental group had a total effective rate of 76.3% Enumeration data were compared by X2 test. The results were considered statistically significant at P .05.  Sequential therapy with 755 nm pulsed dye laser and 595 nm long pulsed alexandrite laser is a safe and effective treatment approach for relatively deep or thick hemangioma.

title: Correlation between thermoluminescence and optically stimulated luminescence responses of natural alexandrite.
abstract: Luminescent properties of alexandrite crystals (BeAl2O4:Cr3+ are studied. Partial readouts of thermoluminescence (TL) and optically stimulated luminescence (OSL) signals were obtained to infer the relations of OSL and TL trapping centers. Four TL peaks were studied; their intensities decrease at different rates by illumination with blue OSL light. The OSL curve shows two time components (exponential decay constants 3.15 and 28.4 s) The short time component is preferentially diminished when the sample is heated to temperatures from 363 to 513 K. About 50% of the whole TL intensity remains after a complete 300s OSL readout.

title: A randomized split face, investigator blinded study of a picosecond Alexandrite laser for post inflammatory erythema and acne scars
abstract: The 755 nm picosecond Alexandrite laser has been demonstrated to be effective and well tolerated in patients with acne scars. In this split face, investigator blinded study, 16 patients with post inflammatory erythema (PIE) and acne scars were randomized to receive laser treatment on half the face, with the other half serving as a control. The treatment side demonstrated a significant improvement in both PIE and scars compared to the baseline and also when compared to the control side. Treatment was well tolerated, with only transient and mild erythema and edema reported as side effects. In our study, the picosecond Alexandrite laser was safe and effective in the treatment of PIE and acne scars. Comprehensive treatment outcomes should be taken into consideration when deciding on which device to use.

title: Minocycline induced hyperpigmentation: rapid resolution after 755nm alexandrite picosecond laser treatment
abstract: Minocycline induced pigmentation (MIP) is an infrequent complication of minocycline therapy, with four subtypes each with distinct clinical features and histologic staining patterns. MIP may resolve following discontinuation of minocycline therapy or it may persist indefinitely. A 64 year old Caucasian male presented with a 6 month history of progressive blue gray facial pigmentation distributed symmetrically over his face. One session utilizing a 755 nm picosecond Alexandrite laser resulted in immediate and significant clearance of the pigment in all treated areas. Long term follow up at 2 years revealed no recurrence of the MIP.

title: Treatment of Refractory Melasma in Asians With the Picosecond Alexandrite Laser.
abstract: The picosecond Alexandrite laser was studied in our practice with the diffractive lens array and the flat optic to treat melasma.  Sixty patients with melasma were treated in a prospective investigation with the picosecond Alexandrite laser. Nineteen patients were treated with the flat optic and 41 patients were treated with the diffractive lens array. Treatments were performed with 1 pass at 2 week intervals for 6 treatments. The Melasma Severity Index (MSI) was used to evaluate the patients before treatment and 3 and 6 months after the final treatment session.  At 6 months after the last treatment, there was an 18.5% difference between the groups with a 75.7% improvement in the MSI in patients with the diffractive lens array and a 57.2% improvement in the MSI score in patients with the flat optic. At 6 months, there was recurrence of melasma in 5% of the cases with no hyperpigmentation with the diffractive optic in contrast to recurrence in 16% of the cases in the flat optic group and a transient macular hyperpigmentation in 21% of the cases.  This investigation highlights the utility of a picosecond Alexandrite laser with a flat and diffractive lens to successfully treat a large percentage of Asian patients in a sunny climate.

title: Alexandrite laser induced uveitis pigment dispersion: A case report and review of the literature
abstract: To describe a complication of an upper eyelid alexandrite laser procedure.  A 55 year old woman presented with left eye blurred vision and photophobia after a left upper eyelid procedure with an alexandrite laser. She had elevated intraocular pressure (IOP) anterior chamber cell and pigment, posterior synechiae, and retroillumination defects in the left eye. She was treated with topical prednisolone and brimonidine. Six months later, although her anterior chamber had cleared and IOP had normalized, the patient reported decreased vision related quality of life from persistent photophobia.  Importance Alexandrite lasers are commonly used for hair removal and skin depigmentation. When used periocularly without proper eye protection, they have the potential to create irreversible ocular complications. This case demonstrates the importance of proper eye protection with periocular laser procedures.