Role Of Laser Research Articles

Hemangiomas and laser therapy: clinical experience

Background Hemangiomas are common benign vascular tumors characterized by a proliferative growth phase followed by very slow and inevitable regression. They are classified as capillary, cavernous, and mixed lesions, 60% are localized on the head and neck but they can be found in all regions of the body. Most of the lesions are focal and solitary, while 15%–20% are multiple with involvement of extracutaneous sites. Although hemangioma is usually benign, its growth is very unpredictable, due to uncontrollable endothelial cell proliferation, and complications are frequent because hemangiomas can evolve in ulceration. We present our clinical experience on the role of lasers to treat port wine stains, superficial hemangiomas, and cafe au lait macules.

Lasers and Thermal Spray

Basically, thermal spray and laser processing can be considered as half brothers since they show many common features due to the use of a (more or less) high-energy source for both. Their combination can therefore be very fruitful and prominent to achieve coatings, which results in their most recent and advanced applications. In the materials processing development story, the laser will thus have moved from cutting to coating. This keynote presentation focuses on the recently-developed coupling of laser processing to cold spray). In this dual process, a cold spray gun is combined to a laser head in a single device, e.g. on a robot. Series of coating experiments using various laser irradiation conditions, primarily pulse frequency, were carried out for Al-based and Ni-based alloys. Laser pre-treatment of the substrate just prior to cold spray, was shown to be beneficial for adhesion of cold-sprayed coatings. Adhesion improvement was exhibited and studied from LASATesting (LASAT for “LAser Shock Adhesion Test”). Incidentally, through LASAT also, the role of lasers in the development of thermally-sprayed coatings can be considered as major. Results are discussed in the light of a TEM (Transmission Electron Microscope) study of the coating-substrate interface with and without laser pre-treatment.

Aura of technology and the cutting edge: a history of lasers in neurosurgery

In this historical review the authors examine the important developments that have led to the availability of laser energy to neurosurgeons as a unique and sometimes invaluable tool. They review the physical science behind the function of lasers, as well as how and when various lasers based on different lasing mediums were discovered. They also follow the close association between advances in laser technology and their application in biomedicine, from early laboratory experiments to the first clinical experiences. Because opinions on the appropriate role of lasers in neurosurgery vary widely, the historical basis for some of these views is explored. Initial enthusiasm for a technology that appears to have innate advantages for safe resections has often given way to the strict limitations and demands of the neurosurgical operating theater. However, numerous creative solutions to improve laser delivery, power, safety, and ergonomics demonstrate the important role that technological advances in related scientific fields continue to offer neurosurgery. Benefiting from the most recent developments in materials science, current CO(2) laser delivery systems provide a useful addition to the neurosurgical armamentarium when applied in the correct circumstances and reflect the important historical advances that come about from the interplay between neurosurgery and technology.

Theoretical calculation of atomic data for plasma spectroscopy

AbstractIn the present article, a number of theoretical approximations and numerical methods, varying in complexity, are reviewed, in order to facilitate their selection for plasma diagnostic purposes. Results refer to highly charged ions, particularly in the lithium isoelectronic sequence. This article describes progress in understanding the role of laser induced degenerate state phenomenon on resonances obtained by using lasers. This type of process, implicitly included in the R-matrix Floquet calculation, contributes to some degree, to the overall behavior of the resonance profiles. The present article gives comparative results obtained fromab initionon-perturbative treatment and perturbative calculation of autoionization widths in Be-like ions. The effective oscillator strength for complex highly ionized atoms is, also, provided. Such calculations are of interest as they represent accurate benchmark data for beam emission spectroscopy, Zeff analysis, or complex atoms modeling in fusion plasma devices.

Laser Materials Processing in Japan

AbstractJapan is one of the most advanced countries in terms of manufacturing technologies, and the role of lasers has become increasingly important since the beginning of 21st century [1]. The Japanese laser market is expanding steadily and competing with existing manufacturing technologies. In this article, recent market trends of laser processing systems using CO2 lasers, solid state lasers and excimer lasers in Japanese market are outlined. Hot topics of successful laser‐based manufacturing technologies for largescale production are also introduced.

Role of lasers in the treatment of benign pigmented lesions

Benign pigmented lesions are often treated for cosmetic reasons. Several modalities exist for the treatment of such lesions, with the aim being clearance of the lesion with acceptable cosmetic results. Cryotherapy and surgical excision of benign pigmented lesions result in inevitable scarring and the cosmetic end points may not be achieved. Such therapies may be declined by patients. The availability of lasers has made it possible to achieve clearance of these lesions with excellent cosmetic results. Although interest in such lasers has arisen in the past few decades, few studies comparing the efficacy of lasers and traditional treatment modalities exist.

OC80: Severe twin–twin transfusion syndrome (TTTS)—is there a role for laser beyond the conventional gestational age guidelines?

OC80: Severe twin–twin transfusion syndrome (TTTS)—is there a role for laser beyond the conventional gestational age guidelines?

Question 1: Is There a Role for Lasers in the Treatment of Peri-implantitis?

Question 1: Is There a Role for Lasers in the Treatment of Peri-implantitis?

Analysis and Prediction of Size Effect on Laser Forming of Sheet Metal

Geometric effects play an important role in laser forming processes; however, few investigations have explored geometric effects other than those induced by sheet thickness. In this paper, the influence of component size or size effect, including variation of sheet width and sheet length, on laser-induced deformation is experimentally, numerically, and analytically investigated. An experimental matrix is designed to cover a wide range of sheet width and length for experiments and numerical simulation under different process conditions. Distinctive trends in bending angle are identified for varying sheet width, length, or both. The results are interpreted in terms of heat sink effect and bending nonuniformity. An analytic model is developed to facilitate size effect prediction. The model is based on the solution to a moving strip heat source over a finite size sheet. It also accounts for the pre-bending effect among consecutive segments on the scanning path. Analytical results are compared with an existing analytical model and numerical simulation.

A review of laser and photodynamic therapy for the treatment of nonmelanoma skin cancer.

The role of laser and light sources used alone and in conjunction with photodynamic therapy (PDT) for the treatment of nonmelanoma skin cancers (NMSCs) remains unclear. PDT is a newly accepted treatment option for actinic keratoses (AKs) with clearance rates comparable to 5-flourouracil. The purpose of this study was to review literature pertaining to the use of light-emitting technologies and PDT for the treatment of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and AKs. A National Library of Medicine PubMed Internet search of English-language journals was performed using the terms laser, PDT, BCC, SCC, and AK. The search encompassed all English-language clinical trials on human subjects from the mid-1960s to the present using laser and light source therapy and/or topical aminolevulinic acid. Articles were excluded if they contained fewer than 10 patients, had a follow-up time of less than 1 month, used intravenous photosensitizers, or were review articles. A total of 20 papers were included for review (10 for BCC, 4 for AK, and 6 for SCC). Follow-up for these patients ranged from 1 to 36 months. Clearance rates were reported up to 100% for superficial BCCs, AKs, and SCC in situ, and lower (8%) for more invasive SCC. Recurrence rates ranged from to 0% to 31% for superficial BCCs, 16% to 31% for AKs, 0% to 52% for SCC in situ, and 82% for invasive SCC. Precise PDT and laser clearance and recurrence rates for superficial and nodular BCC and SCC treated with laser and PDT are not yet known. From the available data, it appears that PDT may be capable of achieving clearance rates comparable to radiation therapy for BCC. However, with current technology, PDT treatment of BCC remains inferior to surgical excision and Mohs surgery, for which recurrence rates have been reported to be less than 10%. The reported clearance rates currently limit the usefulness of PDT and laser therapy. However, multiple treatments and the use of penetration enhancers may significantly increase the efficacy of 5-aminolevulinic acid-PDT. With regard to SCCs, the risk of metastatic disease restricts the use of laser and PDT. Studies are currently underway with new light sources, photosensitizers, and various therapeutic regimens. At this time, because the reported recurrence rates are significantly higher than those achieved with standard therapies, laser and PDT should be reserved for only those patients who cannot undergo surgical therapy for BCC and SCC.

Laser leg vein treatment: a brief overview

Laser treatment of leg veins has been associated with a number of disadvantages, but the introduction of new devices has increased the role of lasers in the treatment of leg veins. This paper reviews the role of laser devices applied from the surface in the treatment of reticular and spider veins. Success is determined by the proper selection of wavelength, fluence, pulse duration, spot size, and number and frequency of treatments.

The use of lasers and intense pulsed light sources for the treatment of acquired pigmentary lesions in Asians

Asians are prone to the development of lentigines as a result of photoageing. Lasers and intense pulsed light sources have been used in the treatment of lentigines but there is a risk of post‐inflammatory hyperpigmentation in Asian skin. This report examines the role of lasers and intense pulsed light sources in treating lentigines and other acquired pigmentary lesions in Asians.

Role of laser in cutaneous vascular lesions of head and neck

Advances in laser physics and laser tissue interactions have enabled otolaryngologists, facial plastic surgeons, and dermatologists to safely and effectively treat the cutaneous vascular lesions of the head and neck in which conventional methods have failed to give good results. Nd:YAG, KTP, argon, and yellow lasers (e.g., dye laser) are the most common lasers used in such lesions. A short series of laser-managed cutaneous vascular lesions of the head and neck, done at the National Institute of Laser-Enhanced Sciences (NILES), is presented and discussed in this article. These lesions are treated as office-based procedures either without anaesthesia, or using local anaesthesia. Considering that improvement is the goal and that residual evidence of the vascular lesion is to be expected, our results are more than satisfactory.

The role of lasers in dentistry: present and future.

Lasers have been used for hard tissue cutting in dentistry for a number of years. The quality of the cavity preparation and the surface finish achievable is variable and is dependent on operating wavelength. The collateral damage, which may be produced at differing wavelengths, is quite marked. Lasers in current form are now able to remove tissue in bulk at a similar rate to conventional methods such as bur and turbine handpiece. Some lasers may, however, provide precision cutting, which may be developed further in the future. Alternative uses of laser light are potentially more beneficial in the shorter term. The use of diode lasers as a means of activating a photosensitizer to carry out photo-activated disinfection appears to be beneficial.

Laser and intense pulsed light therapy for the esthetic treatment of lower extremity veins.

The role of lasers and intense pulsed light sources has gained increasing popularity over the last decade. Major advances associated with improved results are the main reasons associated with this increasing popularity. These advances include epidermal cooling technologies, variable spot sizes and pulse durations as well as the ability to deliver high-energy fluences. These advances have allowed the delivery of sufficient energy to cause uniform pan-endothelial necrosis without affecting epidermal structures causing adverse sequelae such as post-inflammatory hyperpigmentation and epidermal surface irregularities. The advent of extended-pulse longer-wavelength technologies such as the 1064 Neodymium : Yttrium Aluminum Garnet (Nd : YAG) laser have allowed the treatment of individuals with darker phenotypic skin types as well as deep blue reticular veins up to 3mm in diameter in a monomodal fashion. Combined approaches of sclerotherapy plus laser treatments performed at the same treatment session may produce synergistic results in selected individuals.

A novel detection system for laser cooling of ortho-positronium

We report on the development of a position-sensitive scintillation detector system for viewing laser-cooled ortho-positronium (oPs) annihilation points. Ortho-positronium can be cooled down to a recoil limit of 0.1 K by an ultraviolet laser in spite of its relatively short lifetime. In order to perform this experiment the wavelength of Cr:LiSAF laser is considered to be 243 nm which corresponds to the transition energy of 1S–2P states of oPs. Thermal positronium plays an important role in laser cooling of oPs. We investigated various kinds and sizes of inorganic scintillators . Position resolutions of YAP:Ce and CsI(Tl), respectively, were determined to be 3.00 and 3.8 mm. Extensive Monte Carlo simulation studies were performed to view the decay positions of oPs using the time-of-flight method. Related issues of position resolution measurements and oPs decaying points will be discussed.

Recent advances in laser therapy for the treatment of cutaneous vascular disorders.

The use of lasers for the treatment of cutaneous vascular disorders has expanded rapidly since its inception in the early 1960s. The flashlamp-pumped pulsed tunable dye laser (PDL), which is the best laser system for the treatment of port-wine stains (PWS), is based on the premise of selective photothermolysis. Recent literature demonstrates enhanced selective photothermolysis by modifying the PDL to include a longer pulse width, a longer wavelength and higher energy fluences through the use of dynamic cooling. Multiple pulse laser irradiation, a new innovative method, shows promising preliminary results in eradicating hypertrophic PWS. In the treatment of capillary haemangiomas, previous uncontrolled studies suggest benefit with early PDL therapy but a recent randomised controlled trial does not support this claim. Mixed haemangiomas respond poorly to PDL treatment, uncomplicated tumours are best left to involute spontaneously whilst life/organ-threatening lesions require early active intervention. The efficacy of lasers in the treatment of telangiectatic leg veins (TLV) remains controversial. The literature revealed many conflicting claims. Larger and properly controlled studies are necessary to better define the role of lasers in the treatment of TLV.

Gas Dynamic Effects on Laser Cut Quality

The presence of a gas jet plays an important role in laser cutting. Both the cutting efficiency and cut quality are very sensitive to gas pressure and nozzle standoff distance because of the complex nature of shock fronts and associated phenomena in a supersonic gas jet impinging on a workpiece. An idealized case is considered first, where the cut is assumed to be a circular hole directly underneath and concentric with the gas jet nozzle. A more realistic case of an axisymmetric nozzle impinging on a plate with a linear cut is considered next. Unlike the idealized case, the problem now is three-dimensional. Simple experiments to measure the through-kerf mass flow rate were carried out for both geometries. The two important forces exerted by the gas jet for melt ejection, namely, shear force and pressure gradient, show the same trend as that of the mass flow rate with varying gas pressure and standoff. The mass flow rate for the three-dimensional case shows the same behavior as that of the axisymmetric case, indicating the basic shock structures of the axisymmetric case are applicable to the real cutting cases. Laser cutting of mild steels under the corresponding conditions was performed, and the cut quality characterized by roughness, dross attachment, and recast layer thickness was analyzed. The deterioration of cut quality with the gas pressure and standoff is found to closely match reductions in through-kerf mass flow rate. It is thus verified that the shock structure of the gas jet and the associated mass flow rate have a direct impact on laser cutting as predicted.

Laser blepharoplasty and periorbital laser skin resurfacing.

Standard blepharoplasty was developed in the early 1990s by minute descriptions of new anatomic details and surgical procedures derived from endoscopic surgery and by the introduction of lasers as cutting and ablative instruments. The combination of these innovations with deep frontotemporal and mid-facial lifting has added a new dimension to periorbital rejuvenation. This contribution deals with the role of lasers within the scope of expanded periorbital surgery. Indications and surgical techniques of standard and extended laser-assisted blepharoplasties are described. For upper lid blepharoplasty, the CO(2) laser is compared as a cutting instrument to the radiosurgical microelectrode needle. In performing a lower lid blepharoplasty different options are given to choose a minimal invasive transconjunctival approach in combination with laser skin resurfacing or to perform a standard transcutaneous dissection but using the laser for cutting only. With increasing anatomic and surgical knowledge as well as refinements of instruments, it has become evident that the surgeon must define clear positions when to take advantage of these new procedures. Therefore, pros and cons of standard and laser-assisted blepharoplasties will be discussed.

The role of lasers in the treatment of leg veins.

New developments in laser technology have enabled improved therapy of small and large leg telangiectasia. While sclerotherapy remains the gold standard of treatment, laser therapy should be considered a first line approach for isolated, superficial, fine-caliber, nonarborizing telangiectasia and postsclerotherapy telangiectatic matting. Laser therapy is an excellent option for patients who are fearful of needles or have demonstrated a poor response to sclerotherapy injections. Recent studies have demonstrated good clearance of leg telangiectasia and reticular veins using a variety of laser systems with deeper penetrating, near-infrared wavelengths and higher fluences in conjunction with various epidermal cooling methods. As with sclerotherapy, optimal results are achieved with lasers when larger feeding vessels are treated first using appropriate modalities.