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[en] This paper tests the Environmental Kuznets Curve hypothesis for four local (SOx, NOx, CO, VOC) and two global (CO2, GHG) air pollutants. Using a new panel data set of thirty OECD countries, the paper finds that the postulated inverted U-shaped relationship between income and pollution does not hold for all gases. A meaningful Environmental Kuznets Curve exists only for CO, VOC and NOx, where for CO2 the curve is monotonically increasing. For GHG there is indication of an inverted U-shaped relationship between income and pollution, but still most countries are on the increasing path of the curve and hence the future development of the curve is uncertain. For SOx it was found that emissions follow an U-shaped curve. Based on the empirical results, the paper concludes that the Environmental Kuznets Curve does not hold for all gases, it is rather an empirical artefact than a regularity.
[en] Full text: Although the potential of magnetic resonance imaging as a tool for noninvasive diagnosis of cardiac diseases has been recognized, its widespread adoption in clinical practice is only recently gaining pace. MR images allow for assessment of cardiac anatomy and function, myocardial perfusion, vitality infarction, coronary arteries. Educational purposes: to present the specific type of sequences for cardio MR; to explain the principles of ECG synchronization for increasing image quality; to learn how to obtain good morphological images; to learn how to obtain good functional images. Magnetic resonance imaging of the heart requires differentiation of complex anatomical structures and detailed demonstration of anomalies. Cardiac MRI extends the possibilities for diagnosing a wide range of heart diseases
[en] Full text: Introduction: In recent decades Computed Tomography established itself as one of the most common study with a very wide range of applications and techniques of scanning. Best diagnostic value of the method resist to the risks of ionizing radiation, as statistics show that CT is one of the main sources of continuously increasing dose to the population. What you will learn: The physical parameters of the X-ray tube and the principles of image reconstruction; The relationship between variables parameters and the received dose; The ratio between the force and voltage of the current to the image quality, Influence of the used contrast medium to the physical properties of the image, The ratio of patient BMI to image processing, Effective use of knowledge for the optimal CT protocol. Discussions: The goal to reduce the dose received by the patient during a CT scan while keeping the diagnostic quality of the image puts to the test as handset X-ray producers and technicians who need to master the technique of study protocol forming as well as to balance the harm - benefit ratio. Among the most popular techniques are these of dose modulation, low-dose computed tomography at the expense of a reduction of the current or voltage intensity, and control of the number of post-processing algorithms for the image reconstruction. Conclusion: The training of radiologists and X-ray technicians plays a major role in optimizing of technical parameters in view of the reduction of the dose for the patient, while maintaining the diagnostic quality of the image
[en] Full text: In Bulgaria, like in all developed countries, medical exposure is the main source of technogenic population exposure above natural background levels. In contrast to the personnel exposures, in the medical exposure the dose limits are not applied. Therefore, the International Commission on Radiological Protection (ICRP) recommends establishing the dose limits or recommended levels for the patients exposure which to serve as a reference point for the optimization of the performed procedures. The aim of the paper is to present a new kind software solution designed to provide automated collection of quantitative dosimetry data for patients undergoing multidetector CT (MDCT). The tasks arising from this aim are related to analysis, an additional statistical processing and interpretation of the results obtained in optimizing the protocols for testing and improving professional practice. Radiation protection in medical exposure should always be considered in conjunction with the benefits of diagnosis and treatment, and therefore comes to the fore the requirement for quality assurance of diagnostic and therapeutic process. Automatic tracking of dose and module for further analyzes allow a proper assessment of the practice, a good compromise between image quality and received dose as well as the achievement of the basic principles of radiation protection ALARA - reducing of radiation exposure to a reasonable minimum
[en] Magnetic resonance imaging of the breast implants has been shown to be highly accurate in detecting complications and superimposed disease into the surrounding breast parenchyma. However, there are some clinical problems with these patients - a lack of accurate information on the materials used for breast implants because of the long interval between implantation and MRI and cross-signal intensity of the pathological tissue, based on the conventional T1 and T2 sequences. The aim of the article is to explain the physical aspects of some specific MR sequences, focused on the selective tissue characterization. The main principles of the different water-, silicone- and fat suppression techniques are presented with some image and case selective illustrations. (authors) Key words: MAGNETIC RESONANCE TOMOGRAPHY. BREAST AUGMENTATION. MULTISHOT ECHO-PLANER IMAGING. SILICON
[en] In the Radiology Department of Tokuda Hospital Sofia, a strong control over the radiation dose for all patients was accepted with the implementation of the Dose Watch software. The system allows bad practices to be discovered and improves the efficiency and quality of the CT procedures performed in the department. The article will briefly demonstrate the main steps, which have been done, and the results, which have been achieved. The purpose is to identify the challenges, the available tools, and the opportunities for improving the patients' dose in the CT sector of a general Radiology Department. Collected data was based on the information concerning the radiation dose absorbed by individual patients undergoing MDCT examinations in a general radiology department with an overall annual rate of around 7000 MDCT examinations. All of them were carried out using a single 64row MDCT system. The hospital logbook was used to identify the number of CT examinations and dose levels associated with some typical diagnostic procedures in order to make an analysis. The information was taken form the PACS and Dose Watch software and was analyzed. The article draws some measures towards improving the organization and reducing the dose, keeping the quality of the performed exams. Thanks to the supportive software for dose tracking, analyzing and reporting, some problems have been solved and some reasonable measures have been implemented into the daily practice. (authors) Key words: RADIATION DOSE. MDCT. DOSE REDUCTION. REFERRAL GUIDELINES.CTDI. DLP
[en] The purpose of this work was to review the reasonable measures that should be implemented as part of a routine practice in the process of managing CT radiation risks in a typical average radiology department. Based on 6 y of experience in the management of a general radiology department and the newly implemented supportive software for dose tracking, analysing and reporting, the approach towards radiation risk reduction is presented. Thanks to this approach, some problems have been resolved, and reasonable measures have been introduced into daily practice. (authors)
[en] The aim of presented study was to develop a magnetic resistance phantom for evaluation and analysis of reproducible tissue-selective techniques with signal cancellation from silicone, adipose tissues, and water. The task was to provide physical and mechanical stability of the phantom and to obtain stable repeatable measurements by three different researchers with different experience. A breast phantom with separate cavities containing silicone implant, lard and saline was developed. Series of more than twenty datasets images were acquired by three researches. Sequences performed included Ax STIR with silicine suppression and aX STIR with water suppression using manual pre-scan and manual center on the selected peak. Data were analyzed bu Kolmogorov- Smirnov test, Paired Samples t-test and pearson correlation coefficient to evaluate the correlation between researchers. A good mechanical stability of the phantom has been achieved, which allows its long term application under different conditions. Thermally and physically stable, the phantom is also applicable for measurements with different magnetic fields in different clinical centers. Comparative analysis of the mean values shoed no significant statistical difference observed by researches 2 and 3. A statistically significant difference (<0.05) was observed comparing the measurements of researcher 1 with the others. There is no correlation between the measurements of the three researchers. The proposed breast phantom can be used for obtaining reproducible measurements that allows its implementation in clinical practice for tissue selective applications. Also the phantom could help for raising technician qualification and training while performing this type of sequences and for significant reduction of the processing time.
[en] The cylinder-cells metaplasia of the esophagus or Barrett esophagus (BE) is known as a high potent praecancerosis. The dimensions of the lesion are one of the most important prognostic criteria. The aim of the study is to evaluate the diagnostic possibilities of 99mTc-scintigraphy for both lesion size and localization determination. The study involved 11 patients with histological data for BE and 6 control persons. Single lesion was established at four patients; two or more lesions - at seven. The rest six persons examined did not show lesions at all. The study proved that the 99mTc-scintigraphy provided reliable imaging of the cylinder-cells metaplasia areas in the esophagus. It also gives an opportunity for BE mapping which is very important for disease control and prognosis. (author)