Der Radiologe
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In order to secure and continually improve radiation protection standards in the field of medical X-ray imaging, the German X-Ray Ordinance requires that each individual examination be properly justified and that any procedure undertaken be optimized. Diagnostic reference levels have been introduced in Germany as a measure of optimization for common and/or high-dose X-ray procedures, and are regularly checked for compliance by the competent Medical Experts Office. ⋯ The aim of this paper is to describe the essential dosimetric concepts and methods used for the assessment of radiographic, fluoroscopic, and CT procedures. In addition, practical measures for reducing the radiation exposure of patients and personnel will be discussed.
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With an increasingly aging population we are faced with the problem of an increasing number of dementia patients. In addition to clinical, neuropsychological and laboratory procedures, MRI plays an important role in the early diagnosis of dementia. ⋯ Overall the diagnosis of dementia can be improved by using parameters from MR spectroscopy. This article focuses on MR spectroscopic changes in the physiological aging process as well as on changes in mild cognitive impairment a precursor of Alzheimer's dementia, in Alzheimer's dementia, frontotemporal dementia, vascular dementia and Lewy body dementia.
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MR spectroscopy (MRS) is a non-invasive method for investigating tissue metabolism. In the clinical setting proton spectroscopy based on the hydrogen nucleus ((1)H) is primarily used for determining concentrations of important brain metabolites. This paper illustrates the physicochemical principles of MRS and the requirements for high quality spectra. Moreover, different techniques for acquiring localized spectra are demonstrated.