Lasers in Medicine
Year:2009 | Volume:6 | Issue:1 (31)|Papers Count:7

Objectives: his randomized controlled clinical trial was designed to evaluate the efficacy of single-session, nonthermal, carbon dioxide (CO2) laser irradiation in relieving the pain of minor recurrent aphthous stomatitis (miRAS) as a prototype of painful oral ulcers. Fifteen patients, each with two discrete aphthous ulcers, were included. One of the ulcers was randomly allocated to be treated with CO2 laser (1 W of power in de-focused continuous mode) and the other one served as a placebo. Before laser irradiation, a layer of transparent, nonanesthetic gel was placed on both the laser lesions and the placebo lesions. The patients were requested to grade their pain on a visual analog scale up to 96 h post-operatively. The reduction in pain scores was significantly greater in the laser group than in the placebo group. The procedure itself was not painful, so anesthesia was not required. Powermetry revealed the CO2 laser power to be 2-5 mW after passing through the gel, which caused no significant temperature rise or any visual effect of damage to the oral mucosa. Our results showed that a lowintensity, non-thermal, single-session of CO2 laser irradiation reduced pain in miRAS immediately and dramatically, with no visible side effects.

Introduction: Oral mucositis is a common morbid condition which is associated with chemotherapy and radiotherapy for which there is no standard treatment or prophylactic method. According to past studies the use of low level laser therapy (LLLT) can reduce the severity of mucositis and xerostomia in such conditions, both as treatment and a prophylactic factor.Material and Method: Thirty nine patients with head and neck cancer who were being treated with radiotherapy in Cancer Insittiue of Iran enrolled in the study. Patients were randomized to LLLT and placebo treatment starting on the Ist day of radiotherapy through the whole period of their treatment. Objective assessment of the degree of mucositis and xerostomia was recorded every other day by a physician blinded to the type of treatment.Results: All 39 patients developed degrees of mucositis during their course of radiotherapy. The patient in placebo groups had experienced sever mucositis (grade III and IV) more than LLLT treatment group significantly (p=O.04) (75.6% V.s.57.1%). The median of incidence time of sever mucositis in LLLT group 21 days after beginning of radiotherapy in which it is 16 days in placebo group. There was no significant difference between LLL T and placebo group. according to xerostomia.Conclusion: LLLT is capable of reducing the severity and duration of oral mucositis associated with radiation therapy. However for detection of LLLT efficacy on xerostomia, it is necessary long time follow-up.

In this paper, the temperature distribution in denthin when radiated by a pulse Er: YAG laser has been evaluated.For this reason, we consider dentin expose by a pulse laser and heat is generated. The nonhemogenous time dependent heat conduction equation has been solved analytically and by using the boundary conditions the temperature distributin has been derived. The obtained results then applied for dentin and by using the dentin datas, the temperature distribution has been plotted. The effect of pulse energy and pulse duration on the temperature distribution have been studied and discussed comprehensively.

Background/objective: Diagnosis of melanoma in the early stages can have a significant effect on decreasing the mortality rate caused by this type of skin cancer. Melanoma is hard to be diagnosed in the early stages, even by the best physicians. Therefore, providing a method to easier the early diagnosis of this type of cancer is very valuable and vital.Materials & Methods: In this research, by extraction of images' features and classifying them, we proposed an algorithm which enables the melanoma diagnosis. In the first step, before proper features' extraction, we used polarized filter with proper angle for determining accurate boundaries between the normal and affected tissue. In the next step, with help of dermatologists we extracted the lesion's features. Moreover, we optimized the different features in order to have an exact and accurate classification of skin lesion and reduction in classifier training time.Results: Features optimization occurred via three following methods: Principal Component analysis, sequential forward selection and consultation with the dermatologist. By classifier help, all the optimized features were classified, enabled us to complete the algorithm. In the condition that we used the SVM classifier and optimized features with the direct ordinal selection method, the algorithm succeeded in diagnosing melanoma with the approximate accuracy of 91%.Conclusion: The proposed method is useful for diagnosing the melanoma with a convenient price and considerable high accuracy. Also, this software package has the connection capability to dermatoscopy and is helpful for diagnosing the melanoma.

Basal cell carcinoma (BCC) is the most common skin cancer which has significant local invasion and morbidity.Hence the development of new therapeutic strategies is of almost interest. Surgical excision has been the most often used therapy for BCC for many years but the development of a new treatment with best cosmetic outcome and minimum scar formation is of increasing interest. Photodynamic therapy (PDT) is a novel non-invasive therapy for BCC, especially in patients who are not suitable candidates for surgery, which leads to minimum injuries in surrounding non-tumoral tissue. Furthermore, PDT may have some prop hylactic roles against new BCC formation in certain patients. In this article we are going to present a brief history of PDT and review its potential role in treatment and prevention of different types of BCC.

Objectives: In this paper a noninvasive quantitative assessment tool has been developed for studying the effectiveness of nonablative Pulsed Dye laser rejuvenation, using high frequency ultrasound imaging. Using the proposed method, and by monitoring the region of interest before and after rejuvenation, changes in tissue conditions as a result of skin rejuvenation can be investigated.Materials and methods: High frequency ultrasound scans were obtained from 30 patients undergoing Pulsed Dye laser skin rejuvenation. Two markers were extracted from the obtained images, exploiting image processing techniques. A combinational score was developed based on the extracted markers for quantitative analysis of high frequency ultrasound images.Results: The extracted markers illustrated meaningful changes through skin rejuvenation phases. They were also able to discriminate before and after images properly (p<0.05). The combinational score was able to detect before and after images in 87% of cases.Concl~sions: The introduced noninvasive and quantitative approach may be used for assessment of tissue rejuvenation after nonablative laser treatments. The proposed measure is a good candidate for studying collagen regeneration as a result of tissue rejuvenation.