Background and Aims: Although the use of the laser in medical applications has increased dramatically during the last three decades, it is significant that during the last few years non-laser light sources have gained prominence in photomedicine and photosurgery, particularly the use of light-emitting diodes (LEDs) and intense pulsed light (IPL). The author therefore believed it was important to devise a new classification of light/tissue interactions, and that the well-accepted acronym LLLT and HLLT should now stand for low level light therapy and for high level light treatment, since the ‘L’ in ‘laser’, LED and IPL stands for ‘light’.
Rationale: The author herein presents a classification, which is based on the level of reaction induced by the light incident on tissue, rather than being based on the system used to deliver the light energy. When the level of tissue reactivity to light of very low incident power and energy densities is well below the cells’ damage threshold, so that instead of being damaged the cells are directly activated by the low incident photon density, the changes in the irradiated tissue are photoactivative and reversible: the author hereafter refers to this group of reactions as low level light therapy (LLLT). When the level of tissue reactivity to light of very high incident power and energy densities is over the cells’ damage threshold, so that the cells are directly destroyed, the changes in the irradiated tissue are photodestructive and irreversible: the author hereafter refers to this group of reactions as high level light treatment (HLLT). For levels of tissue reaction intermediate to HLLT and LLLT, the author suggests the new term, medium level light treatment (MLLT), as described in detail herein.
Conclusions: When the new classification system of light treatment (LT) is understood and used, the author feels this offers an accurate and simple method of classifying light/tissue reactions by the therapeutic reaction itself, rather than by the light source, laser, LED, IPL system or other, used to produce the reaction.

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Visible light at high intensity was found to kill bacteria while low-power light in the visible and near infrared region enhances bacterial proliferation. The present review summarizes evidence demonstrating that the mechanism of visible light- bacteria interaction involves reactive oxygen species (ROS) generation. The ROS are photo induced by bacterial endogenous photosensitizers. Phototoxic effects were found to involve induction of high amounts of reactive oxygen species (ROS) by the bacteria while low amounts of ROS may promote their proliferation. Intense blue light, preferably at 415nm, is better than red light for bacteria killing.

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Background: Fifteen years have passed since the first Intense Pulsed Light (IPL) devices were introduced into the market. A variety of devices that use light energy for aesthetic puposes are currently manufactured by several companies, and newer devices offering improved performance and features are periodically being introduced. Herein we present our experience with the MP-22 device (Lumenis Ltd.,Yokneam, Israel) for cosmetic treatment of benign skin lesions.
Patients and Methods: We collected patient data from all patients who received IPL and Nd:Yag laser treatments with the MP-22 over a one year period (Jan 2009 - Jan 2010). The study group included 92 patients who were treated on the face, neck, trunk and hands. The main indications for treatment were lentigo and superficial vascular lesions. Patient age ranged from 16 to 72 years old, and 89 patients were female. Exclusion criteria for treatment were suspicion of skin cancer, isotretinoin treatment during the previous 6 months, and pregnancy. Satisfaction after treatment was evaluated by the patients on a scale ranging from 0 to 5, with 5 = excellent, 4 = very good, 3= good, 2= moderate improvement, 1= mild improvement and 0= no improvement.
Results: Ninety-three percent of the patients were satisfied (rating 3, 4 or 5 on the above scale). Ninety-five percent of the patients had one or two treatment sessions. Of the treatments, 82 were on the face, two on the neck, four on the trunk and 13 on the dorsal aspect of the hands. Minor side effects such as erythema for longer than 24 hours and facial edema for more than one day were reported by 9 patients. Major complications such as scars, hyperpigmentation or hypopigmentation were not recorded. The fluence delivered varied from 14 - 18 J/cm².
Conclusion: IPL is an effective and safe method for skin treatments, namely removal of vascular and pigmented lesions.

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Background: Optical fibers are generally used with a flat cut end. The adaptation of a coaxial exit of a refrigerated gas near the distal tip of the optical fiber cools the tissue where the laser beam is applied and reduces the injury of thermal effects on biological tissue.
Materials and Methods: We have changed the flat end geometry of the fiber’s end to a pyramidal end shape (named: Diamond tip). In this project we have evaluated the new shape of the fiber’s end using laboratory tests and in real conditions. We have examined the emission pattern in the air and in water as well as its performance in surgery.
Results: With the new shape better results were obtained: higher power density, more utilizations of the same fiber (after sterilization) resulting in economical savings. The diamond tip is characterized by greater mechanical resistance then conical tip delivery systems. The greater resistance of the Diamond tip prevents optical fiber breakage during surgery. The delivered system can be reshaped by a trained hospital physician and reused. Our experience shows that delivery systems intended by the producer to one use only can be converted, by reshaping their tips, to highly performing delivery systems, which can be reused many times. In addition less power was needed, with less tissue penetration. The thermal effect was minimized and higher mechanical resistance was achieved, which allowed reusing the fiber more than six times. The special structure of the faces of the optical fiber diamond tip eased its sliding.
Conclusion: The Diamond tip is superior to other fiber end tips by having minimal thermal effects, higher mechanical resistance and by being reused many times.

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Background: Combination therapies are increasingly being used for the treatment of acne.
Objective: 2 years of clinical experience using a combination of drugs with LHE™ phototherapy on moderate to severe acne patients.
Methods: Patients first underwent a series of 8-10 bi-weekly LHE treatments to reduce their dermal inflammatory process. These treatments were combined with keratolytic agents which are not contraindicated with phototherapy. The combined LHE/drug treatment regimen was followed by a series of LHE skin rejuvenation procedures to treat post acne symptoms of localized erythema, post inflammatory hyperpigmentation and scars.
Conclusions: This double phototherapy protocol appears to offer excellent clinical and aesthetic results with no side effects or complications and may be repeated if relapse occurs.

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Background and Aims: Near-infrared laser-assisted lipolysis has claimed attention recently as a fast, safe and effective way to remove unwanted fat from various areas of the body. Removal of fat from the face has however proved more difficult. A novel 1444 nm line of the micropulsed Nd:YAG has recently been developed, offering superior duality of absorption in both fat and water. The present preliminary study was designed to assess the efficacy of the 1444 nm wavelength in facial and body contouring.
Subjects and Methods: Twenty-four informed and consenting female patients (ages ranging from 23 yr to 59 yr, mean age 32.38 ± 7.26 yrs) were recruited into the study. The laser used was a micropulsed 1444 nm Nd:YAG system. Following tumescent anesthesia, the tip of the optical fiber was placed in the subcutaneous fat via a cannula inserted through a small puncture wound, and lasing was commenced while the tissue over the end of the optical fiber was continuously palpated to check for excessive heat formation. Cold compresses were applied post-lasing. Patients were followed for at least 2 months with clinical photography at baseline, immediately post-treatment and at subsequent assessment points.
Results: All patients successfully completed the study. Patient subjective satisfaction was high, and an objective clinician assessment from the clinical photography showed good efficacy. There were no major adverse side effects. Minor side effects were transitory, all resolved spontaneously and good results were maintained during a 2 - 3-month follow-up.
Conclusions: The present study showed high efficacy for the 100 μ.s micropulsed Nd:YAG laser at 1444 nm for laser-assisted lipolysis of both body and facial areas, with no adverse side effects and virtually no downtime. The high absorption rate of 1444 nm in both fat and water, coupled with the 100 μ.s pulse, was believed to contribute highly to the success of the study and the satisfaction of the patients. Further larger studies are warranted.

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Background: Low level laser irradiation (LLLI) stimulates bone regeneration. However, the molecular mechanisms leading to this is not yet understood. The stepwise subtractive cDNA cloning technology has been developed, coupled with DNA homology searched in DNA database is useful to identify the certain gene.
Aim: In order to understand the mechanism, we attempted to identify genes whose expressions are enhanced by LLLI. MC3T3-E1 osteoblastic cells were irradiated with an 830 nm Ga-Al-As diode laser, and a cDNA library was constructed using subtractive gene cloning.
Material and methods: The cDNA library of osteoblasts which was treated by LLLI was constructed. Nucleotide sequences were analyzed and homology searched in a DNA database using BLASTN program to identify the gene with altered expression. Altered mRNA levels by LLLI were confirmed by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR.
Results: The DNA sequence of a subtracted gene clone MCL129 indicated high homology (99%) with the microtubule-associated protein 1A (MAP1A) gene. Increase in MAP-1A mRNA level by LLLI was successfully confirmed by RT-PCR and real-time PCR.
Discussion: MAP1A has been shown to promote microtubule assembly and its functional expression. Microtubules play an important role in cell division, cell shape and polarity, cell movement, intracellular transport, signal transduction, and synthesis and secretion of collagen. Thus, enhancement of MAP1A gene expression by LLLI may be one of the molecular mechanisms involved in accelerating bone formation by LLLI.
Conclusion: LLLI irradiation enhances MAP1A gene expression and modulates microtubule assembly and the functional structure of microtubules, in turn, stimulates osteoblastic proliferation and differentiation.

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Background: Rheumatoid arthritis (RA) is an inflammatory joint disorder, whose progression leads to the destruction of cartilage and bone. Chemokines and their receptors are potential therapeutic targets in RA. Among these, it has been suggested that CXC chemokine 4 (CXCR4) and its ligand CXC ligand 12 (CXCL12) are involved in RA pathogenesis. Low-level laser irradiation (LLLI) is currently being evaluated for the treatment of RA; however, the molecular mechanisms underlying its effectiveness remain unclear.
Aim: To understand the anti-inflammatory effect of LLLI, we used the collagen-induced arthritis (CIA) rat as RA model and analyzed the gene expression profile in synovial membrane in the hindpaw joints of control, CIA and CIA + LLLI. Expression of CXCR4 and CXCL12 genes were also studied.
Materials and Methods: Total RNA was isolated from the synovial membrane tissue of CIA rat joints or CIA joints treated with LLLI (830 nm Ga-Al-As diode), and gene expression profiles were analyzed by DNA microarray (41,000 rat genes). The mRNA levels were confirmed by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. Immunohistochemical examination to examine CXCR4 protein expression was also carried out.
Results: DNA microarray analysis showed that CXCR4 gene expression was increased in CIA tissue and LLLI treatment significantly decreased CIA-induced CXCR4 mRNA levels. In contrast, CXCL12 did not show any significant changes. The microarray data of CXCR4 mRNA levels were further validated using RT-PCR and real-time PCR. Increased CXCR4 mRNA levels by CIA and its reduction following LLLI was successfully confirmed. CXCR4 production was increased in CIA joints and its production was decreased by LLLI.
Conclusion: Decreased CXCR4 expression may be one of the mechanisms in LLLI-mediated reduction of RA inflammation.

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