oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 4 )

2019 ( 58 )

2018 ( 143 )

2017 ( 167 )

Custom range...

Search Results: 1 - 10 of 6245 matches for " Radiation Exposure "
All listed articles are free for downloading (OA Articles)
Page 1 /6245
Display every page Item
The Effects of Preoperative Imaging on Surgical Outcome for Pediatric Appendicitis Patients Special Issue: Pediatric Surgery  [PDF]
Henry Su, Laura Nally, Jennifer Maddison, Yi-Horng Lee
International Journal of Clinical Medicine (IJCM) , 2013, DOI: 10.4236/ijcm.2013.47A2007
Abstract: Computed tomography (CT) has been the major imaging modality for the diagnosis of appendicitis because of its excellent imaging resolution and the ease of interpretation, but a concern has been raised regarding radiation exposure. We have shifted from CT to ultrasonography (US) as the primary imaging modality because of this concern. A retrospective review is conducted to determine whether a combined US/CT strategy can reduce radiation exposure while maintaining the same surgical outcome. Five hundred eighty-six patients between 10 and 18 years of age who underwent an appendectomy from 2007-2011wereincluded in our study. The patients were classified as Early (prior to 7/1/2009) or Late (after 7/1/2009) with the knowledge that a conscientious institutional effort was made to start utilizing US as the primary imaging modality, limiting CT use to selective cases in 2009. The diagnostic imaging studies performed (CT, US or no imaging) were recorded. Operative findings, pathology reports and clinical course were reviewed. The rates of acute appendicitis (AA), negative appendectomies (NA) and perforated appendicitis (PA) were calculated. During the Early period, 49.3% of patients (n = 150) had undergone CT scans prior to their appendectomy whereas only 37.9% (n = 107) had CT scans during the Late period. Of the CT scans obtained during the Late period, only 18.4% of patients (n = 52) had a CT scan first, and 55 CT scans were done after an initial US. Patient disease patterns were similar between Early and Late years. While no difference in NA rates for boys was found between the Early and Late periods, a
Contribui??o ao estudo da quilovoltagem nominal preconizada e do tempo de exposi??o de diferentes modelos de aparelhos de raios X odontológicos
BOSCOLO, Frab Norberto;LOM?NACO BRAGA JUNIOR, Dewell;GON?ALVES, Andrea;MONTEBELO FILHO, Agenor;
Revista de Odontologia da Universidade de S?o Paulo , 1997, DOI: 10.1590/S0103-06631997000500008
Abstract: this study intended to assess the performance of dental x-ray machines as regards time of exposure and kilovoltage with an analysis of 127 x-ray machines sold by funk and dabi atlante in the south of minas gerais state. the values obtained, both time of exposure and kilovoltage for each model of x-ray machine studied, were organized into frequency distribution tables and presented in histograms. results obtained, once processed, were indicative of an exposure time performance that was unsatisfactory for funk model x-10, whereas the dabi atlante machines models spectro ii, trophy, and spectro 1070, proved satisfactory as to performance in a comparison of real exposure and nominal exposure times. we examined the nominal kilovoltage of these same machines and, as a whole, they showed lesser kilovoltage than that preconized, indicative of performance short of that expected. professionals are advised of the need for periodic maintenance in order to remedy the deficiencies presented by the machines, at least in part
Padr?o de exposi??o radiológica e preditores de superexposi??o dos pacientes submetidos a procedimentos cardiológicos invasivos em equipamentos com detectores planos
Cardoso, Cristiano de Oliveira;Sebben, Juliana Ca?edo;Fischer, Leandro;Vidal, Milena;Broetto, Gabriel Garcia;Silva, Bruna Santos da;Vargas, Francine Gon?alves;Fontella, Norton Ramos;Kaufmann, Wagner;Rodrigues, Guilherme Oberto;Medeiros, Rogério Fachel de;Cardoso, Carlos Roberto;Sarmento-Leite, Rogério;Gottschall, Carlos Ant?nio Mascia;
Revista Brasileira de Cardiologia Invasiva , 2011, DOI: 10.1590/S2179-83972011000100015
Abstract: background: invasive cardiologic procedures expose patients and physicians to the risks of ionizing radiation. the aim of this study is to determine patterns and predictors of radiation overexposure during cardiologic procedures. methods: prospective cohort study to investigate patients undergoing invasive cardiologic procedures between august 2010 and january 2011 in flat detector fluoroscopy systems. clinical, angiographic and radiation exposure characteristics were recorded in a dedicated database. radiation exposure patterns were determined in patients undergoing coronary angiography, elective (e-pci) and ad hoc (ah-pci) percutaneous coronary intervention. independent predictors of increased radiation exposure were identified by multiple logistic regression analysis. results: the study population included 670 patients, 419 undergoing coronary angiography, 137 e-pci and 114 ah-pci. the mean radiation dose received by the patients was 561.8 ± 368.1 mgy (coronary angiography), 1,125.5 ± 1,120 mgy (e-pci) and 1,293.4 ± 726.3 mgy (ah-pci). dose-area product was 37,725.8 ± 27,027.5 mgy.cm2 (coronary angiography), 61,643.1 ± 64,383.7 mgy.cm2 (e-pci) and 77,973.4 ± 49,959.3 mgy.cm2 (ah-pci). predictors of increased radiation exposure were body weight [odds ratio (or) 1.03, confidence interval (ci) 1.01-1.05; p = 0.003), e-pci (or 11.9, ci 4.3-33.2; p < 0.001) and ah-pci (or 15.5, ic 5.4-43.9; p < 0.001) conclusions: radiation exposure patterns during invasive cardiologic procedures using flat detector fluoroscopy systems are below the threshold established by the international atomic energy agency. body weight, e-pci and ah-pci are predictors of radiation overexposure.
Three influencing factors on the level of non-ionizing radiation  [PDF]
Vasil Bilero
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.211157
Abstract: The role of three factors on the level of non- ionizing radiation is treated in this project: that of 1) the distance of the exposed body from the source, 2) the power of the source device and 3) the frequency of the source. The important factor of time, as well as other factors, are not at all ignored in this manuscript. In this work I emphasise the rules of the relationship with this necessary contaminant, and that exposures towards it should be avoided as far as possible.
Assessment of the Direct Sun-Light on Rural Road Network through Solar Radiation Analysis Using GIS  [PDF]
Christos Chalkias, Antigoni Faka, Kleomenis Kalogeropoulos
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.32030
Abstract:
The movement of vehicles on the roads, during summer, can sometimes hide risks involved in direct sunlight. In places where the relief is complicated, road network usually consists of a road complexity. This complexity in conjunction with the motion of a vehicle on a road and the position of the sun at the same time may result in the loss of vision in some sections of the road. This paper describes a GIS-based methodology of the spatiotemporal analysis of this phenomenon. Thus, for a given study area, in this case ofMilos Island,Greece, the geometry of the road network, the terrain morphology and the solar radiation (in specific time intervals during summer) have been analyzed. The result of this procedure is a map illustrating the sections of the road where direct sunlight includes a serious amount of risk for the drivers. Applying this methodology for long periods of time may lead to prevention policies adoption related to accidents of direct exposure to sunlight. Moreover, this methodology could be an additional module in car navigation systems.
Three-Dimensional Rotational Angiography in Congenital Heart Disease: Estimation of Radiation Exposure  [PDF]
Gloria Reinke, Julia Halbfa?, Sven Dittrich, Rosemarie Banckwitz, Christoph K?hler, Stephan Achenbach, Oliver Rompel, Martin Gl?ckler
Open Journal of Radiology (OJRad) , 2013, DOI: 10.4236/ojrad.2013.33020
Abstract:

Objectives: There is an increasing use of three-dimensional rotational angiography (3D-RA) during catheterization of congenital heart disease. Dose-area-product (DAP) measured by the angiography system and computed-tomography dose index (CTDI) do not appear practical for dose assessment. Hence, we performed real dose measurements in anthropomorphic phantoms. Methods: Three different anthropomorphic phantoms (10 kg, 19 kg and 73 kg bodyweight) equipped with thermoluminescent dosimeters (TLD) were used. We used a typical standard diagnostic program and a low-dose program. The effective dose (ED) was calculated according to the International Commission on Radiological Protection (ICRP) 103. The 3D distribution of radiation in the body was assessed. Results: ED for the male 10 kg phantom was 0.192 mSv in the diagnostic program and 0.050 mSv (male) in the low-dose program. The 19 kg phantom received an ED of 0.205 mSv (male) in the diagnostic program. In the low-dose program the ED reached 0.058 mSv (male). The male adult 73 kg phantom was exposed with an ED of 0.730 mSv in the diagnostic program and 0.282 mSv in the low-dose program. ED for the female phantoms was slightly higher for both acquisition-programs. Dose distribution was inhomogeneous with a dose maximum in the esophageal region behind the heart, whereas in the brain, intestine and gonads we found nearly no radiation. Conclusions: 3D-RA imaging in the interventional catheter laboratory is possible with an effective dose lower than 1 mSv. With its potential to reduce fluoroscopic time and the number of control angiographies in catheterization and intervention in complex anatomy, it can decrease the radiation dose.

Electromagnetic Radiation Health Effects in Exposed and Non-Exposed Residents in Penang  [PDF]
Adlina Suleiman, Thor Teong Gee, Ambigga Devi Krishnapillai, Khalifah Mohamad Khalil, Mohammad Wisman Abdul Hamid, Marami Mustapa
Journal of Geoscience and Environment Protection (GEP) , 2014, DOI: 10.4236/gep.2014.22012
Abstract: A comparative study was conducted between residents exposed and not exposed to electromagnetic radiation (EMR) from TELCO towers in Penang Island with the objective of determining the possible health effects using 14 non-specific health symptoms (NSHS). Interviews on 201 respondents were conducted using structured questionnaire for demographic details, health related problems and the public concern. Comparison of symptoms frequencies and its significance (Chi-square test) between the exposed and not exposed residents from the TELCO tower showed statistical significance (p < 0.05) for headache, giddiness, insomnia, loss of memory, diarrhea, mental slowness, reduced reaction time and mood swing. The odds ratio for the development of the NSHS scored > 1 for all that gave a conclusion that respondents who were exposed were more likely to suffer symptoms as compared to the respondents who were not exposed to EMR. This outcome showed that the existence of TELCO tower in these communities has detrimental health effects towards the residents who were exposed to the electromagnetic fields radiation that was emitted. Measures to be taken to minimize adverse health effects on residents should include imposing more stringent guidelines in terms of safety distance and radiation intensity, practicing of WHO precautionary approach, encouraging electromagnetic fields radiation related conference, researches and public awareness, sharing of transceivers by TELCO companies and using protective barriers. These steps will ultimately promote a healthier, harmonious and sustainable living environment.
Dose Efficiency in Dual Source High-Pitch Computed Tomography of the Chest  [PDF]
Boris Bodelle, Thomas Lehnert, Martin Beeres, Thomas Josef Vogl, Boris Schulz
Advances in Computed Tomography (ACT) , 2014, DOI: 10.4236/act.2014.34008
Abstract:

Objectives: Evaluation of radiation efficiency of dual source high-pitch (DSHP) chest CT in comparison to single source technique with special regards to individual patient anatomy. Methods: 150 consecutive patients who underwent chest CT with automated tube current modulation were evaluated retrospectively and divided into three study groups, each with an equal quantity of 50 patients (DSHP vs. single source 128 slices vs. single source 16 slices). By using a dedicated workstation, volumetric analyses of each of the scanned anatomic area were performed and correlated to the individual dose length product (DLP). The calculated result was defined as dose efficiency. Results: DLP was 203 mGycm (DSHP), vs. 269 mGycm (single source) vs. 273 mGycm (16 slice CT). The total patient volume was lowest in the dual source group with 18956.3 cm3 (vs. 22481.2 cm3 vs. 22133.8 cm3). With regards to the DLP, the calculated dose efficiency of dual source CT was better than the 128 slice CT (p = 0.045) and the 16 slice CT (p < 0.01). Conclusions: DSHP CT has considerably better dose efficiency compared to 16 slice CT. Compared to 128 slice single source technique, the high-pitch mode does not cause any dose penalty when performing chest CT.

Current Status of Radiation Dose Levels in Conventional Pediatric Radiography: A Review Study  [PDF]
Abdelmoneim Sulieman
Open Journal of Radiology (OJRad) , 2015, DOI: 10.4236/ojrad.2015.52016
Abstract: Artificial sources of radiation account for approximately 14% of the annual radiation dose from all sources of radiation. Because of the increased lifetime risk per unit dose for children, radiographic procedures could lead to increase the radiogenic risk of cancer. This study intended to review the pediatric doses in planar radiography procedures and to assess different methods used to reduce the radiation dose for pediatric patients. Studies addressing pediatric dose optimization were identified from a search of the internet scientific databases. The search in literature was limited to journal articles that were written in English. The findings of the study illustrate that there are many available methods of dose reduction are available. The application of dose reduction methods will reduce the dose up to 75% of its current value. Training of staff is the cornerstone of patient dose optimization in pediatric radiology.
Effect of Radioactive Minerals Potentiality and Primordial Nuclei Distribution on Radiation Exposure Levels within Muscovite Granite, Wadi Nugrus, Southeastern Desert, Egypt  [PDF]
S. F. Hassan, M. A. M. Mahmoud, M. A. E. Abd El-Rahman
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.43006
Abstract: The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E. The rock types are represented by layered metagabbros, biotite schists, gneisses, granodiorites, and Muscovite granites. The muscovite granite of Wadi Nugrus, is small exposure in size (~5.0 km2), emplaced along NW-SE trend, with about 0.5 - 4.5 Km in length and 100 - 250 m in width and intruding the biotite schists. The studied muscovite granite is composed mainly of plagioclases, potash feldspars, quartz, biotite and muscovite. The recorded minerals assemblage can be classified into secondary U-minerals (uranophane and meta-autunite), U-bearing minerals (uranothorite and columbite) and accessory minerals (zircon, flourite, allanite, zinnwaldite and hematite). The U/eU is more unity where, the measured chemical uranium is higher than the measured equivalent uranium in the most analyzed samples especially in trenches, which reflect disequilibrium state. The activity concentrations range from 251.72 to 1096.2 Bq·kg-1 for 232Th, from 494 to 2593.5 Bq·kg-1 for 226Ra, and from 1314.6 to 1846.7 Bq·kg-1 for 40K. The obtained radiological data show that the average internal and external hazard indices are 9.11 and 5.78, respectively which are more than unity and highly exceeding the permissible limits (International Commission on Radiation Protection, ICRP). The internal and external
Page 1 /6245
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.