A study of digital x-ray detection systems with optical image transfer

The work describes the performance characteristics of roentgenographic screen-optics-CCD-matrix systems based on the KRTs-1 digital roentgenographic system developed at SpektrAp, Ltd. The efficiency of X-ray detection is estimated from the minimum detectable contrast and maximum resolution. The effect of the X-ray imaging system components on the efficiency of detection is studied. The X-ray screen structure is shown to have a crucial effect on the efficiency of detection as estimated from the image resolution.     

Development of a system controlling x-ray diagnostic devices]

The purpose and criteria for efficiency (errors of anode voltage holding, tube current, and exposure) of the system controlling X-ray diagnostic devices are considered from theoretical and practical points of view. A microprocessor-controlled variant of the controlling system developed for numerous existing six-pulsed generators of the -3 type is outlined. The design and operation of the key circuit diagram of X-ray tube filament in the PEHA 50-6 microprocessor-controlled feeding device are shown in detail.     

Use of digital technology in x-ray television imaging

The questions of decreasing radiation loads in X-ray TV units due to application of digital means of storing X-ray TV images are considered. On the basis of the theoretical analysis of the spatial frequency, time and noise parameters of the X-ray image amplifiers the authors derived expressions relating the input ratio signal/noise of the USSR manufactured URI to the intensity of the X-ray radiation dose of the transformer input. It was established that under the pulse mode of the X-ray unit and storage in the digital memory of the TV unit signal to get the needed ratio signal/noise of the output videosignal (37 dB) it is quite enough to secure on the transformer input the value of the X-ray radiation dose of 15 microR. The functional scheme of the digital unit operating in pulse and pseudodynamic modes of X-ray diagnostic units is outlined.     

Recent history of the shielding of medical x-ray imaging facilities

Since the discovery of x rays by Roentgen in 1895, a progression of reports containing recommendations to reduce the hazards from this "invisible light" have been published. These reports, generated by a number of expert national and international bodies, issued ever-evolving protection guidelines for shielding radiation workers and members of the public from the potential health effects of this radiation. In recent years, significant changes have been made in the recommended dose limits, and a number of articles that provide updated shielding data, parameters, and methodologies for x-ray imaging facilities have been published. Scientific Committee 9 (SC9) of the National Council on Radiation Protection and Measurements (NCRP) (formed with the support of the American Association of Physicists in Medicine), was given the charge of reviewing the literature and updating the NCRP shielding recommendations for x rays used for medical imaging purposes (i.e., for diagnostic and interventional procedures). This article focuses on the new data and models presented in these recent publications and on the recommendations of the current NCRP report, produced by SC9, for the design of radiation barriers in medical imaging facilities.     

Parameters of thermoelectric cooling devices in conditions of variable temperatures of the heat-exchange media

New method for optimized computing thermoelectric coolers is proposed for the case of variable temperatures within heat-transfer media. The operation of the device is analyzed when the temperature of the cooled medium is greater than the temperature of the heated one, i. e. under conditions of the negative temperature difference. The comparative analysis of the computed and experimental data in values of the cooling and electric power demonstrates fully satisfactory results.     

A study of the use of hand-held devices in an emergency department

In a project conducted in 2002 and 2003, the use of hand-held computing devices was examined in a hospital emergency department in Western Australia. Personal digital assistants (PDAs) were used for the wireless development. The study addressed three major issues: development methodology, communication between the mobile devices and existing databases, and user interfaces. The software was tested by about 20 health-care staff, including nurses, doctors, administration staff, information technology staff and front-desk receptionists. The wireless development proved a valuable experience for everyone involved. The product is currently undergoing rigorous testing to meet the standards of the healthcare industry.     

医学影像仪器设备的维修保养方法

在现代医学和新型医院的发展进程中,先进医疗设备起到了决定性的推动作用。本文提出了以维护保养为主,故障维修为辅的新式维修观念,来保证医疗设备的正常使用,使其最大化的发挥其应有效能。     

X线数字化成像技术的应用价值探讨

重点介绍了数字化成像技术的类型、特点、优势以及数字化成像技术的展望，并对各种数字成像技术的应用价值进行探讨．增加医务人员对影像成像方式的了解，以利于影像工作者更好地掌握应用数字化成像技术，为医学影像诊疗事业做贡献。     

医学成像系统显示仪器评价方法的探讨

21世纪最具深远意义的重大变革是医用影像无片化的普遍开展。为适应这种无片化图像诊断的需要而大量使用的显示仪器性能应如何保证是一个重大问题。为此,本文研究探讨了几种不同医用显示器的评价方法。     

The resolving capacity of systems for the reproduction of x-ray images

At digital and film X-ray studies, the geometry of a survey exerts a varying effect on the system's resolution. This may lead to the better quality of digital X-ray image when actual magnification is performed.     

Energy dispersive x-ray analysis in the study of pneumoconiosis.

Identification of inorganic substances in the lung is an important step towards the establishment of a cause and effect relationship in the study of pneumoconiosis. The conventional methods for this identification usually require an ashing which makes it difficult to study the localisation of these substances in relation to pathology. A method is described to identify foreign substances in the tissue obtained either on biopsy or autopsy without destroying them. The technique employs scanning electron microscopy together with energy dispersive x-ray analysis. This method not only allows simultaneous multi-elemental analysis of over 80 elements, but also permits detailed morphological examination while the tissue is being analysed.     

Magnetic resonance imaging systems. A guide to the technology

Magnetic resonance imaging (MRI) has become firmly established as an essential imaging tool. Two characteristics of MRI--its ability to image soft tissue and its avoidance of harmful ionizing radiation--more than compensate for the costs, complexity, safety issues, and patient discomfort associated with it. Today, MRI is the modality of choice for a number of neurological and musculoskeletal indications and is being used for more applications than ever before. In some cases, MRI is supplementing existing techniques, such as vascular and cardiac imaging, while in others it is used to image physiologic processes that are invisible to any other imaging modality. MRI scanners are growing increasingly complex. As the technology develops, capabilities that were once available only to researchers are becoming routine in clinical applications. As a result, buyers now have more decisions to make when selecting a scanner than ever before. It is no longer simply a choice of field strength or whether to opt for an open or closed system. To gain an understanding of the important factors to consider when selecting MRI equipment, it is necessary to have a good understanding of how the systems work. In this article, we describe the operating principles of MRI systems. We also describe the major components of a system and the considerations involved when implementing MR imaging. Finally, we describe the issues surrounding the higher-powered three-tesla systems that are beginning to see commercial use.     

A study of a two-energy bar of detectors for x-ray osteodensitometry

Described are the results of mathematic modeling for different types of detectors (with different scintillators for high- and low-energy spectrum ranges) as well as the results of experimental research. It was also analyzed of how a manufacturing technology of ZnSe(Te) and CsI(Tl)-based scintillators affects the detector-bar resolution ability. Finally, the influence of signals in canals of detectors on the signals in neighboring canals was investigated.     

Assessing maintenance of evaporative cooling systems in legionellosis outbreaks

This study was designed to conduct systematic reviews of existing evaporative cooling system maintenance guidelines and of published Legionnaires' disease outbreaks to determine what, if any, maintenance practices were in place at the time of the disease outbreaks and then to contrast the reported practices with the published guidelines for evaporative cooling systems. For the first review, similarities in the reported recommendations were assessed; in the second review, any reported information about the state of the evaporative cooling system during the outbreak investigation was summarized. The systematic reviews yielded 38 current guidelines for evaporative cooling systems and 38 published outbreak investigations. The guidelines varied regarding the recommended type and dose of biocides, frequency of general inspections and total system maintenance, the preferred disinfection and cleaning procedures when testing a system for microbiological contamination, the type and frequency of testing procedures, and interpretation of test results. Overall, the maintenance guidelines did not contain sufficiently detailed procedures to prevent the problems that were observed in the outbreak investigations. These maintenance procedures included lack or improper use of a biocide; infrequent testing for microbiological contamination; improper use or maintenance of drift eliminators; and lack of a total system cleaning within 6 months of the outbreak for cooling systems that were either under continuous use, recently started up, or frequently switched on and off. This study suggests that more specific and standardized maintenance guidelines for the control of Legionella bacteria are needed and that these guidelines must be properly implemented to help reduce further Legionnaires' disease outbreaks associated with evaporative cooling systems.