Αρχειοθήκη ιστολογίου

Αλέξανδρος Γ. Σφακιανάκης
ΩτοΡινοΛαρυγγολόγος
Αναπαύσεως 5
Άγιος Νικόλαος Κρήτη 72100
2841026182
6032607174

Πέμπτη 14 Απριλίου 2022

Long-term clinical outcomes of immediate loading versus non-immediate loading in single-implant restorations: a systematic review and meta-analysis

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Dental implant restoration is a predictable treatment option for replacing missing or damaged teeth. Conventional loading requires a prolonged treatment period and second surgical interventions. The aim of this study was to compare the clinical outcomes between immediate and non-immediate (early or conventional) loading in single-implant restorations. A literature search of the PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov databases was performed in January 2020. Only randomized clinical trials (RCTs) were included. (Source: International Journal of Oral and Maxillofacial Surgery)
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Poor Treatment Outcomes with Second-Line Chemotherapy in Advanced Synovial Sarcoma

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Via Oncology
CONCLUSION: Our exploratory study revealed that the response rate of second-line chemotherapy regimens for patients with synovial sarcoma was 9.4%. Therefore, there is an urgent need to develop more active therapeutic regimens for synovial sarcomas.PMID:35405680 | DOI:10.1159/000524500 (Source: Oncology)
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SEARCH FOR EXPERIMENTAL EVIDENCE OF DOSE-RATE AND WALL SCATTERING EFFECTS IN THE THERMOLUMINESCENCE RESPONSE OF LIF:MG,TI (TLD-100)

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Abstract
An experimental investigation into the possibility of dose-rate effects and wall scatter in the thermoluminescent response of LiF:Mg,Ti (TLD-100) was carried out. The investigation was motivated by theoretical simulations predicting the possible presence of dose-rate effects coupled with the lack of detailed experimental studies. The dose rate was varied by changing the source to sample distance, by the use of attenuators, sources of 137Cs of various activities, filtration and the construction of identical geometrical irradiators of Teflon and stainless steel. Four levels of dose in the linear dose response region were studied at 10−2 Gy, 1.5 × 10−2 Gy, 0.1 Gy and 0.5 Gy to avoid complications in interpretation due to supralinearity above 1 Gy. At the dose of 1.5 × 10−2 Gy, the dose rate was varied by five orders of magnitude from 4.9 × 10−3 Gy s−1 to 4.9 × 10− 8 Gy s−1. At the other levels of dose, a one to two orders of magnitude in dose rate was achieved. Within the measurement uncertainty of 5–10%, no dose-rate effects were observed in any of the experimental measurements and no changes in the shape of the glow curve were observed. The maximum wall scatter effect (Teflon to stainless steel) was measured at ~8% within the experimental uncertainty and well below expectations. The results are encouraging with respect to the accurate and reproducible use of LiF:Mg,Ti under various experimental conditions of irradiation.
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THE INFLUENCE OF LOW-DOSE OCCUPATIONAL RADIATION EXPOSURE ON PERIPHERAL BLOOD CELLS IN A COHORT OF CHINESE MEDICAL RADIATION WORKERS

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Abstract
Objectives
The study aims to assess the change of peripheral blood cell numbers following protracted low-dose radiation exposure among medical radiation workers.
Methods
A cohort of 375 Chinese medical workers were followed for 5 years (2015–19) and recorded the changes in blood cells and cumulative doses. T-test, least significant difference-T test, variance analysis and correlation analysis were utilized in this study.
Results
Compared with the control group, the white blood cells, hemoglobin counts and the ratio of eosinophils in the study group showed a downward trend. The differences in blood cells between groups were mainly found in the number of red blood cells. In a short cumulative time, such as 1 or 3 years, a correlation between the cumulative dose and the quantity of blood cells was detected, but not at 5 years.
Conclusions
There is no significant difference in the blood cell count s between different types of work, and the long-term cumulative dose has not been statistically correlated with the number of blood cells. So that the number of peripheral blood cells can no longer be used as a good indicator of radiation damage.
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DESIGN AND FABRICATION OF A PEDIATRIC THYROID PHANTOM FOR USE IN RADIO-IODINE UPTAKE MEASUREMENT, IMAGE QUALITY CONTROL AND DOSIMETRY

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Abstract
Estimating internal contamination from 131I for children in nuclear accidents is a crucial subject in the radiation protection field. Throughout this paper, an urgent and simple method was proposed for measuring 131I inside the pediatric thyroid gland by constructing a neck and thyroid phantom. For this purpose, CT scan images of healthy child's thyroids were obtained, and the sizes of different parts were determined by a 3D slicer image processing software. Girls with the body surface area between 0.95 and 1.05 were involved in this study. The fabricated phantom is composed of 5 cylindrical slabs of 2-cm thickness, and several small holes were constructed for TLD dosemeters near the thyroid gland and all other parts of the neck. The phantom was constructed utilizing a 3D printer with acrylonitrile butadiene styrene plastic. The thyroid phantom was filled with radioiodine-131, and calibration curves were plotted for contam ination estimation. A nodular thyroid phantom was also constructed. The nodular phantom or the resolution phantom has 4 removable parts containing cylindrical holes with diameters of 3, 6, 9 and 12 mm. These holes on the thyroid glands can be filled with different activities of radionuclides to serve as hot and cold spots for quality control of nuclear medicine images. The results show that the designed phantom is applicable in different fields such as nuclear image quality and resolution tests, dosimetry and iodine thyroid uptake estimation in nuclear medicine departments, and nuclear emergency monitoring.
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