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Objective:Objective To investigate the role of radiotherapy in the treatment of refractory keloids, evaluate the self-assessment degree of satisfaction of patients and compare with the objective outcomes.Methods:A total of 144 patients (290 lesions) with refractory keloids admitted to Peking Union Medical College Hospital from 2013 to 2018 were included in this study. The median age was 28 years old (range: 15-81 years old). All lesions were subjected to electronic radiation at postoperative 24h. The regime of 5 to 7MeV electron beam radiation therapy was adopted. The total dose was ranged from 16 to 18 Gy/2f (at 1-week interval). The median follow-up time was 48 months (range: 35-91 months). Patient and Observer Scar Assessment Scale (POSAS) was used to evaluate the degree of satisfaction. Multivariate analysis was performed by Cox proportional hazards model.Results:Among 290 keloids, 52 keloids (17.9%) relapsed in 3 to 42 months from the end of radiotherapy (median 12 months). The main side effects were hyperpigmentation and local incisional extension. Univariate analysis showed that local incisional color darker than skin, pruritus, pain and young age were associated with recurrence. Multivariate analysis indicated that local incisional color darker than skin and pain were the independent prognostic factors for scar recurrence. Recurrence, hyperpigmentation and local incisional extension were the main reasons for patients′ dissatisfaction.Conclusions:Postoperative electronic radiation can achieve satisfactory efficacy in the treatment of refractory keloids. Local incisional color darker than skin and pain are the independent prognostic factors of keloid recurrence. Patient self-assessment results are not fully consistent with the objective clinical outcomes and recurrence status.
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Objective To observe the gastric changes in adult male Sprague-Dawly (SD) rats irradiated by the single large dose electron beam,providing animal experimental evidence for intraoperative radiotherapy for gastric cancer.Methods Thirty-eight SD rats were randomly divided into the control and experimental groups.The stomach of the rats in the experimental group were subject to single 6 MeV 20 Gy irridiation by using the patent technology of Accurate Irradiation Experiment Table for Small Animal Radiation.The general conditions,gastric injury and body weight change were observed at different days following irradiation.Results The most severe gastric damage of rats was observed on the 14th d after irradiation.The gastric injury was gradually repaired accompanied with glandular atrophy at 28 d postirradiation,and the gastric injury was manifested as cellulose fibrinous repair on the 56th d after irradiation.Within 1 week post-irradiation,weight loss was noted in the experimental group,which significantly differed from the rats in the control group (P＜0.05).During the 2nd week,the body weight was increased in the experimental group,significantly lower compared with the rats in the control group (P＜ 0.05).The body weight of rats did not significantly differ between two groups at 6 weeks after irradiation (P＞ 0.05).Conclusions The most severe gastric injury is observed at 2 weeks after the single-dose 6 MeV electron beam 20 Gy irradiation,whereas no gastric perforation occurs.The gastric injury can be restored to normal status within 8 weeks following irradiation.
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Background: Oral health diseases are common in all regions of the world. Mouth rinses are widely used generally by population as a port of daily oral care regimen. In addition to antimicrobial activity, mouth rinses possess certain cytotoxic effects. Electron‑beam (E‑beam) radiation is a form of ionizing energy known to induce structural, physical, and chemical changes in irradiated products. In this study, the modulatory effects of E‑beam in irradiated mouth rinses were evaluated for its biological activities. Materials and Methods: The antimicrobial activities of nonirradiated and irradiated mouth rinses were evaluated for its antimicrobial and antibiofilm activities against oral pathogens, Enterococcus faecalis, Streptococcus mutans, Staphylococcus aureus, and Candida albicans. The antimicrobial activity was evaluated by disc diffusion method and antibiofilm activity was evaluated by O’Toole method. The cytotoxicity was evaluated against human gingival fibroblast (HGF) cells by 3‑(4, 5 Dimethythiazol‑yl)‑2,5‑Diphenyl‑tetrazolium bromide assay. Results: Colgate Plax (CP) exhibited the antimicrobial activity against the tested pathogens, and a significant (P < 0.05) increase was observed against S. aureus at 750 Gy irradiation. Further, CP significantly (P < 0.05) suppressed S. mutans, S. aureus, and C. albicans biofilm. Listerine (LS) inhibited S. mutans and C. albicans biofilm. Whereas irradiated CP and LS significantly (P < 0.05) suppressed the biofilm formed by oral pathogens. The suppression of biofilm by irradiated mouth rinses was dose‑ and species‑dependent. There was no significant (P > 0.05) difference in the cytotoxicity of irradiated and nonirradiated mouth rinses on HGF cells. However, an increased percentage viability of HGF cells was observed by mouth rinses irradiated at 750 Gy. Conclusion: The E‑beam irradiation enhanced the antibiofilm activity of mouth rinses without modifying the cytotoxicity.
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Aim: The aim of this study is to investigate whether dental nanocomposite Filtek Z350 XT and Ceram X-duo can benefit from electron beam irradiation in order to achieve increased flexural strength Place and Duration of Study: Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangalore, India and Microtron Centre; Department of Physics Mangalore University; Mangalore, India between May 2011 to March 2014. Materials and Methods: Materials were prepared on rectangular bar shaped specimens of 25-×2-×2-mm according to ISO standard -4049. Electron beam irradiation dose selected for the study were 1KGy, 3KGy and 5KGy. In total, 48 specimens were fabricated and divided into 4 groups based on radiation dose group I (non-radiated), group II (1KGy), group III (3KGy), group IV (5KGy) with 12 specimens in each. After 24 hours, specimens were subjected to 3-point bend test on a universal uniaxial servo mechanical testing machine. Statistical Analysis: Performed using one way ANOVA and inter group comparisons were done using tukeys multiple comparision. ‘P’ value<0.05 was considered statistically significant. Results: Flexural strength of Filtex Z350 XT before radiation was170.89±9.07.Flexural strength of Filtex Z350 XT after irradiation with 1KGy, 3KGy and 5KGy was found to be 269.06±94.91, 326.53±54.74 and 377.64±74.5 respectively. P value statistically significant (P<0.0001). Flexural strength of Ceram X duo before radiation was120.14±7.12.Flexural strength of Ceram X duo after irradiation with 1KGy, 3KGy and 5KGy was found to be 206.27±76.38, 177.31±67.35 and 229.33±59.15 respectively. P value statistically significant (P<0.0001). Conclusion: It can be concluded that electron beam irradiation can be used as a tool to modify the present day dental materials for enhancing their mechanical properties.
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Aim: The aim of this study was to evaluate the cytotoxicity of three resin luting agents Rely X luting cement, Rely X luting 2 cement and Clearfil SA luting cement before and after electron beam irradiation. Materials and Methods: Growth and maintenance of cell cultures of human pulp cells was done in Dulbecco’s modified Eagle’s Medium (DMEM). The test samples were divided into two Categories: Irradiated Category and Non-radiated Category. Samples in Irradiated category were exposed to electron beam radiation at 200Gy. Three subgroups of radiated category and non radiated category were made. All the samples were subjected to MTT assay and spectrophotometric analysis and their cytotoxicity was assessed. Statistical analysis was done using t test. Results: Evaluation of Rely X luting Cement showed that radiated samples of powder, liquid and set cements showed decreased cell viability than non radiated samples. In Case of Rely X luting 2 cement, radiated samples showed increased cell viability for Paste A and Paste B samples. But in set material, irradiated samples showed decreased cell viability as compared to non radiated samples. For Clearfil SA luting Cement, Paste B showed increased cell viability for radiated samples. Paste A and Set cement of radiated samples showed decreased cell viability than non radiated samples. Conclusion: In the present study , the increased cytotoxicity of irradiated samples may be due to increase in the release of unbound monomers which may be due to chain breakage after irradiation and a reduction in the cytotoxicity which may be due to the cross linking of unbound monomers during irradiation.
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PURPOSE: To obtain the uniform dose at limited depth to entire surface of the body, the dose characteristics of degraded electron beam of the large target-skin distance and the dose distribution of the six-dual electron fields were investigated. MATERIALS AND METHOD: The experimental dose distributions included the depth dose curve, spatial dose and attenuated electron beam were determined with 300 cm of target-skin distance (TSD) and full collimator size (35x35 cm2 on TSD 100 cm) in 4 MeV electron beam energy. Actual collimated field size of 105 cmx105 cm at the distance of 300 cm could include entire hemibody. A patient was standing on step board with hands up and holding the pole to stabilize his/her positions for the six-dual fields technique. As a scatter-degrader, 0.5 cm of acrylic plate was inserted at 20 cm from the body surface on the electron beam path to induce ray scattering and to increase the skin dose . RESULTS: The full width at half maximum (FWHM) of dose profile was 130 cm in large field of 105x105 cm2. The width of 100+/-10% of the resultant dose from two adjacent fields which were separated at 25 cm from field edge for obtaining the dose unifomity was extended to 186 cm. The depth of maximum dose lies at 5 mm and the 80% depth dose lies between 7 and 8 mm for the degraded electron beam by using the 0.5 cm thickness of acrylic absorber. Total skin electron beam irradiation (TSEBI) was carried out using the six dual fields has been developed at Stanford University. The dose distribution in TSEBI showed relatively uniform around the flat region of skin except the protruding and deeply curvatured portion of the body, which showed excess of dose at the former and less dose at the latter. CONCLUSION: The percent depth dose, profile curves and superimposed dosedistribution were investigated using the degraded electron beam through the beam absorber. The dose distribution obtained by experiments of TSEBI showed within+/-10% difference except the protruding area of skin which needs a shield and deeply curvatured region of skin which needs boosting dose.
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Humanos , Mano , PielRESUMEN
Objective To compare the accuracy of output factor calculation for rectangular inserts of electron beams by using three kinds of algorisms: square root, one dimensional formula and area periphery ration. Methods The differences between the values of output factor calculated by these three algorithms mentioned above and the results measured by ionization chamber for seven rectangular inserts were compared. Results When beam energy was fixed, the difference between calculated and measured output factors was larger for area periphery ration algorithm than that of the square root or one dimensional formula algorithms. The electron cone size, beam energy and rectangular inserts size all had some effect on the value of output factor calculated by the three algorithms. Conclusions The area periphery ration algorithm is not recommended for clinical use because of its great deviation. One dimensional formula and square root algorisms possess a good accuracy. One dimensional formula is superior to square root algorithm, but square root algorithm is more practical for clinical use.