Digital chest radiography: an update on modern technology, dose containment and control of image quality

The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems

An Experimental Comparison of Flat-Panel Detector Performance for Direct and Indirect Systems (Initial Experiences and Physical Evaluation)

The purpose of this work was to compare direct and indirect detectors in terms of their system linearity, presampled modulation transfer function (MTF), Wiener spectrum (WS), noise equivalent quanta (NEQ), and power spectrum. Measurements were made on two flat-panel detectors, GE Revolution XR/d (indirect) and Shimadzu Safire (direct) radiographic techniques. The system linearity of the systems was measured using a time-scale method. The MTF of the systems was measured using an edge method. The WS of the systems was determined for a variable range of exposure levels by two-dimensional Fourier analysis. The NEQ was assessed from the measured MTF, WS, and estimated ideal signal-to-noise ratios. Power spectrum analyzed the chest phantom within artificial lesions. System linearity was excellent for the direct systems. For the direct system, the MTF was found to be significantly higher than that for the indirect systems. For the direct system, the WS was relatively uniform across all frequencies. In comparison, the indirect system exhibited a drop in the WS at high frequencies. At lower frequencies, the NEQ for the indirect system was noticeably higher than for the direct system. Power spectrum for the direct system was relatively flat and similar to that for white noise. The indirect system exhibited significant reduction at high spatial frequencies. In general, the direct systems exhibit improved image quality over indirect systems at comparable exposure dose

Radiation protection: Factors influencing compliance to referral guidelines in minor chest trauma

Objectives: To test the hypothesis that referral guidelines are not sufficiently known by prescribers and that medico-legal concerns could influence the prescription of radiographs in minor chest trauma. Methods: We submitted a questionnaire including a typical clinical history and questions on reasons for prescribing radiographs of the ribs in minor chest trauma to 112 prescriptors (33 residents, 18 surgeons, 7 internists, 24 general practitioners and 30 ER physicians). All accepted to participate. Comparisons were performed by Fisher's exact test followed by a post-hoc analysis and by a McNemar test. Results: Fifty-eight percent of prescriptors proposed rib radiographs, most (89%) being unaware of the guidelines. Only 11% of them changed their intention to order radiographs after information on referral guidelines and radiation dose (P=0.057). The mean dose delivered by rib radiographs was 38 times higher than that of a chest X-ray. Legal and medico-legal concerns (requirements from insurance policies and avoidance of lawsuits) were the main reasons for requesting radiographs. Conclusion: Unsharpness of guidelines in addition to social and medico-legal issues, rather than medical reasons or the lack of knowledge of the guidelines, strongly influence the prescription of radiographs of the ribs in minor chest trauma. Key Points: • Most prescriptors order radiographs of the ribs in minor chest trauma. • Only few prescriptors are aware of referral guidelines. • Information on guidelines does not change their need for radiographs. • Motivations for ordering radiographs are rather legal than medical, but poor compliance to guidelines could also be explained by their unsharpness. • Radiation dose of rib radiographs was 38 times that of a PA chest radiograph.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Tourism and health, risks and challenges

Whilst the entry ‘tourism, health and well-being’ articulates the consensus that tourism experiences can have health benefits for individuals and societies, there are also health risks involved when it comes to international travel. Tourists and tourism organisations need to be aware of and to manage such risks in order to mitigate the potentially far reaching health consequences. By its nature, tourism involves the movement of people from place to place and as such increases the unplanned exposure of tourism stakeholders to a variety of health related risks. This entry takes a tourism, tourist and community perspective rather than a health or medical practitioner stance, in order to highlight some of the risks and challenges that may emerge in the context of tourism and health

Foodborne pathogens and host predilection

During food manufacturing, the potential exists for contamination of products with pathogenic microorganisms. While the ingestion of a bacterial pathogen will typically result in illness in a susceptible host, it is not the case for each strain within a given species. Pathogenic bacteria display various levels of host specificity: some infect a wide range of hosts, while others have strict host selectivity and are obligate pathogens. Host specificity of bacterial pathogens is determined by multiple molecular interactions between both the pathogens and their hosts. Understanding these interactions in detail will allow risk-based decisions to be made on affected foods, informed by knowledge of specific strains or pathotypes. This has the potential to avoid costly and unnecessary recalls with classical pathogens that can be proved to have a low potential for causing illness

Division of data according to CSF HIV RNA detectability reveals distinct CD8 T-cell and monocyte inflammatory responses correlations with NC impairment in the HIV RNA detectable and HIV RNA undetectable conditions.

<p>*values were square root transformed</p><p>** P value from ANOVA</p><p>Division of data according to CSF HIV RNA detectability reveals distinct CD8 T-cell and monocyte inflammatory responses correlations with NC impairment in the HIV RNA detectable and HIV RNA undetectable conditions.</p