Medical laser application : international journal for laser treatment and research最新文献

Background and objective

Gold-coated silica core nanoparticles have an optical response dictated by plasmon resonance. The wavelength at which the resonance occurs depends on the core and shell sizes, allowing nanoshells to be tailored to particular applications. The purpose of this in vitro study was to synthesize and use different concentrations of gold nanoshells as exogenous material for skin tissue soldering and to examine the effect of laser soldering parameters (irradiance, number of scans and scan velocity) on the properties of repaired skin.

Materials and methods

Two protein solder solutions mixed with albumin solder and two different gold nanoshell concentrations (1 and 2 ml) were prepared. A 2-mm-thick, 20-mm-long incision was made on the surface of depilated sheep skin strips using a surgical blade, and after the addition of the solder solution, it was irradiated with a diode laser (810 nm), varying the irradiance I (24–83 W/cm²), the number of laser scans N_s (2–10 scans), and the scan velocity $v_s$ (0.2–0.42 mm/s). The temperature T was monitored using a digital K-type thermometer (CHY502A1, CHY Firemate Co., Taiwan) that was positioned under the skin with a probe diameter of 0.5 mm and a response time of 0.1 s. Approximately 30 min after the completion of the soldering process, the tensile strength σ was evaluated in a tensile test.

Results

The results show that the tensile strength of the repaired skin increased with increasing laser irradiance for both gold nanoshell concentrations. At a constant irradiance, the tensile strength of the repaired incisions increased with increasing N_s and decreasing $v_s$. A higher irradiance resulted in a larger tissue temperature rise.

Conclusion

It was demonstrated that gold nanoshells can be used for laser tissue soldering, provided that the operating conditions are carefully optimized. In our case the optimal parameters were: σ = 0.16 N/mm² at I ∼ 60 W/cm², T ∼ 65 °C, N_s = 10 and $v_s=0.2\text{mm/s}$.

Background

No therapy can remove acne scars completely, but the discerning use of lasers can help to relieve patients of related symptoms. Electro-optical synergy (ELOS), a technology that combines radiofrequency (RF) with optical energy, shows multiple application potential, including hair removal and reversal of photoaging.

Objective

Using the case reported here as an example, we discuss the role of the ELOS technology in the treatment of acne scars.

Case report

The acne scars of a female patient (age 34, Fitzpatrick skin type IV) were treated with ELOS. The patient was treated monthly for a total of 4 sessions with a Matrix IR™ system (Syneron Medical Ltd.), a combination of a fractional diode laser (915 nm) and bipolar conducted RF energy, using the following parameters: 60 J/cm² (laser energy) and 80 J/cm³ (RF energy). Acne scars were markedly reduced 1–3 months after the final treatment.

Conclusion

This technology encompasses a combination of optical and RF energies which are simultaneously applied to the tissue and demonstrate the safety and efficacy in the treatment of acne scars.

Excimer lasers (193 nm) can be used for photoablation of the human cornea due to their specific physical characteristics. This laser is applied in corneal refractive surgery for the targeted removal of corneal tissue for the purpose of correcting refractive errors. This article provides a short overview of the scientific development of excimer lasers for use in ophthalmic surgery and of the range of applications of these tools.

Introduction

The malignant melanoma of the choroid is the most common primary malignant intraocular tumor in adults. There are currently several methods available for the treatment of choroidal melanomas. Among others, hyperthermia represents a therapeutic approach in which infrared radiation is delivered through the dilated pupil, called “transpupillary thermotherapy (TTT)”. The method was initially assumed to cause only a few side effects but gradually more and more complications have been observed. The treatment is associated with a number of vascular responses, for example arterial and venous occlusions. However neovascularizations of the choroid have only been detected twice so far and represent an extreme rarity.

Case report

We report on the case of a 70-year-old patient, who developed a choroidal neovascularization (CNV) after we had performed TTT on a subfoveal choroidal melanoma with a prominence of 3.25 mm and a base of 7.95 mm × 7.87 mm. Due to insufficient regression of the tumor, the TTT was repeated twice. An indocyanine green (ICG) angiography, performed 8 months after the last TTT, showed a sea fern-shaped CNV, situated subfoveally in the area of treatment. However, leakages or accompanying hemorrhages (common in CNVs found in age-related macular degeneration) were not observed.

Conclusion

The development of CNV is known after excessive use of photocoagulation causing damage to the Bruch's membrane/retinal pigment epithelium complex which implies a risk for the development of CNV. The appearance after TTT seems to be exceptional because TTT uses heat at a level below that required for photocoagulation. Our observation could be a sign of intraocular heat damage as a long-term consequence of TTT.

Background

Trabeculectomy is the most commonly performed glaucoma filtering surgery. The success of the outcome of an operation to reduce the intraocular pressure (IOP) is dependent on postoperative wound modulation by antimetabolite therapy and by flow regulation of the filtering bleb, which can be achieved by argon laser suture lysis.

Methods and case report

Postoperative IOP controls, examination of bleb formation and bleb massage can lead to the decision to perform up to four argon laser suture lyses in order to reduce IOP and enhance aqueous humor flow and bleb formation. The procedure is described here in a case report.

Conclusion

After glaucoma filtering surgery, argon laser suture lysis is an effective tool for postoperative regulation of aqueous humor flow and formation of the filtration bleb to guarantee the success of surgery.