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The scattering coefficient of yellow spruce needles exceeds that of green needles by a factor of 2, whereas the fluorescence efficiency is approximately equal for both needle colours. As shown by the angular distribution the fluorescence light is diffusely emitted. However, the scattered light consists of a diffuse and a reflecting portion below 20 degrees with a ratio of the intensities of 1 : 2 at perpendicular observation (0 degrees). Control measurements show that in the rejection region the effective transmission of cut-off-filters commonly used to separate fluorescence light and excitation light exceeds the value calculated from the filter specifications by a factor of 100. Therefore, the portion of the scattered light in the measuring signal must be controlled if the fluorescence induction kinetics is measured from specimen of different colour. A device for the determination of the fluorescence induction kinetics is described which employs a He--Ne laser, a mechanically working shutter with an opening time of 4 ms for the excitation, and a computer for data storage and device control. Two filters select the fluorescence components at 685 nm and 730 nm and they reduce the portion of the scattered light in the measuring signal to 0.18% and 0.55%, respectively. In order to consider the temporal development of the fluorescence kinetics the sampling rate is reduced from 2 kHz to 1 Hz. From the data stored in the computer maximum value Fp, and steady-state-value Fs are determined for both fluorescence components. Measurements on 4-year-old spruce exposed to ozone-concentrations of 0, 300 ppb, 600 ppb, and 1000 ppb were repeated every week. With increasing concentration and duration of treatment Rfd = (Fp-Fs)/Fs was decreased for both fluorescence components. With the highest ozone concentration a reduction of Rfd of 23% and 24%, respectively, was obtained for the two fluorescence components after three weeks.
As the issue of data overload is a problem in critical care today, it is of utmost importance to improve acquisition, storage, integration, and presentation of medical data, which appears only feasible with the help of bedside computers. The data originates from four major sources: (1) the bedside medical devices, (2) the local area network (LAN) of the ICU, (3) the hospital information system (HIS) and (4) manual input. All sources differ markedly in quality and quantity of data and in the demands of the interfaces between source of data and patient database. The demands for data acquisition from bedside medical devices, ICU-LAN and HIS concentrate on technical problems, such as computational power, storage capacity, real-time processing, interfacing with different devices and networks and the unmistakable assignment of data to the individual patient. The main problem of manual data acquisition is the definition and configuration of the user interface that must allow the inexperienced user to interact with the computer intuitively. Emphasis must be put on the construction of a pleasant, logical and easy-to-handle graphical user interface (GUI). Short response times will require high graphical processing capacity. Moreover, high computational resources are necessary in the future for additional interfacing devices such as speech recognition and 3D-GUI. Therefore, in an ICU environment the demands for computational power are enormous. These problems are complicated by the urgent need for friendly and easy-to-handle user interfaces. Both facts place ICU bedside computing at the vanguard of present and future workstation development leaving no room for solutions based on traditional concepts of personal computers.(ABSTRACT TRUNCATED AT 250 WORDS)
A new system for direct digital intraoral radiography, Sens-A-Ray, is presented. This system is based on a detector with a charge-coupled device that was designed especially for direct exposure to x-ray radiation. The system also includes interface electronics and an IBM AT-compatible personal computer with a digital I/O with frame memory, a super VGA graphics board, a high-resolution monitor, and software for the exposure, capture, storage, and enhancement of images. An external optical mass storage device is used for permanent storage of images in digital format. A video printer may be used to create hard copies. The system produces radiographic images at a significantly lower exposure than required for E-speed intraoral film. Applications of the system are exemplified, and its basic properties are discussed.
An experimental radiologic reporting system has been developed and tested. The rewritable and compact magneto-optical disk (MOD) is applied to storing medical images with oral diagnostic reports of these radiologic images. The disk is 5.25 inches in diameter, has 600 MB memory capacity, is erasable, light and compact. Advantages are simultaneous recording of radiologic images and their oral reports by radiologists, and application to circulation of media inside the hospital as well as to filing of medical images. The MOD has a multimedia function of communication and filing. When medical images are taken and stored, oral interpretation by radiologists can be simultaneously added. Physicians can get information of the images and their reports by oral speech at the same time in front of computer workstation. Furthermore, integration of a voice recognition capability is now being undertaken.
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Organizational techniques that enable small departments to function efficiently often fail as departments become larger. With the recent growth in imaging technology, the capacity of film-based systems to meet the increasing needs of radiology departments has decreased. Electronic picture archiving and communication systems (PACS) have been developed in an attempt to provide economical storage, rapid retrieval of images, access to images acquired with multiple modalities, and simultaneous access at multiple sites. Input to a PACS may come from digital or analog sources (when the latter have been digitized). A PACS consists primarily of an image acquisition device (an electronic gateway to the system), data management system (a specialized computer system that controls the flow of information on the network), image storage devices (both short- and long-term archives), transmission network (which serves local or wide areas), display stations (which include a computer, text monitor, image monitors, and a user interface), and devices to produce hard-copy images (currently, a multiformat or laser camera). The goals of PACS are to improve operational efficiency while maintaining or improving diagnostic ability.
A computed radiography system (Digiscan, Siemens) connected to an image workstation (Siemens) has been used for 1 1/2 years in our department. The image quality is good and it has been possible to reduce radiation dose by about 30% without any appreciable loss of image quality. The image workstation has been used in cases where image postprocessing is considered to be useful. For routine reporting of X-ray images the workstation is too slow although the image quality is comparable to that of the computed radiography film.
Optical disc technology can be either analog or digital. Analog (videodiscs) simulation programs are available for the allied health professions educator to incorporate into the curriculum. Digital optical discs, currently available in three formats, follow standards that have been adopted by the International Standards Organization. The formats differ in the amount of information they can accommodate and their practical use in the health professions curriculum.
A system developed for long-term simultaneous recording of oesophageal motility and pH in the ambulant patient is described. The system consists of a microprocessor based data-acquisition and preprocessing device, a personal computer for postprocessing, report generation and data storage, a miniature two-sensor pressure catheter and a pH electrode. Identification and classification of oesophageal contractions are performed in separate steps, using online preprocessing software for identification and offline postprocessing software for categorisation, classification and report generation. Contractions are categorised as peristaltic, simultaneous or nontransmitte and classified according to their amplitude, duration and propagation velocity. The method described reduces the amount of data from 870 kbyte to approximately 40 kbyte per 24 hours in a multiparameter recording device, and offers the opportunity for offline postprocessing with different sets of criteria. The system has been found to be accurate and reliable in 24-hour studies in both healthy volunteers and patients with non-cardiac chest pain.
For data acquisition intensive care neurosurgery increasingly has recourse to modern electronics, which have become an integral part of many aspects of present-day neurosurgery. Despite their high technical standard, the devices in common use often lack flexibility. Their range of possible applications is defined by the manufacturer, and the user has little or no influence on them. Moreover, there are often no adequate interfaces to peripherals, and the storage capacity is limited. We would like to present a data acquisition system on a PC/AT basis, which operates up to 64 channels allowing parallel registration, storage, analysis, and of decisive importance, also various computations, i.e. correlation. Computation is rarely feasible on commercial devices, but it is essential for specific demands, such as implementation of PA/PM diagrams to determine intracranial compliance. In addition, the pertinent software permits implementation of Fourier analyses, offers separate statistical functions, and transfers data to other programs. The program is capable of automatic batch-processing, which greatly facilitates its use.
Several recent technological advances have considerably improved the field of confocal fluorescence microscopy. Improvements in confocal microscope design, new fluorescent probes and indicators, more sensitive imaging devices, and computer advances which allow for data manipulation and storage provide a convenient method to acquire complex three-dimensional (3-D) architectural details which previously were difficult or impossible to obtain from biological specimens. Applications of the laser scanning and tandem scanning confocal microscopes offer the potential for gaining powerful insights into the complex relationship of cellular structure and function. Confocal microscopy generates optical sections free from out-of-focus blur. With the development of new visualization tools to render and display complex 3-D data, a set of optical sections taken at different focal planes can be three-dimensionally reconstructed to create an animated sequence which can reveal latent features of the specimen. The combination of confocal microscopy and 3-D reconstruction provides a powerful new imaging tool to advance knowledge about structural and functional cellular properties as they occur dynamically in three dimensions.
OBJECTIVE: In this article, we describe the implementation of a digital archive center for a radiology department in a 700-bed teaching hospital. MATERIALS AND METHODS: The archive center consists of two identical archive systems, each comprising five components: an archive server, a data-base server, an optical disk library, a stand-alone optical disk drive, and a communication network. An image management system controls the image traffic from acquisition devices to display stations. A fault-tolerant mechanism was built into the archive center to achieve a 100% uptime. RESULTS: The center has been in operation for over 6 months. We have not experienced a single total system failure during this period. It currently archives all digital images from three MR units and four CT scanners and selected images from three computed radiographic systems and two laser film digitizers. The center archives between 1.5 and 2.0 gigabytes of images per workday. CONCLUSION: With its built-in fault-tolerant mechanism, we believe that the implemented archive center is very reliable and is suitable for a radiology department to archive its digital images.
A new hardware device has been constructed to detect QRS and P complexes for the purpose of automatic arrhythmia interpretation. This apparatus can operate in noisy conditions and provide synchronized pulses representative of P complex, QRS complex, wide QRS, and premature QRS to different output channels. P wave identification is achieved with a high degree of reliability through a specially designed bipolar electrode catheter. The device could minimize demands on central processor time and core storage computer.
The rapid improvements in microcomputer systems have contributed to ease of performance of epidemiological research in occupational health. Computers now available can aid in all stages of research- from the early stages of literature review to data collection, analysis and presentation. Optical storage devices now allow large occupational health data bases to be stored on a single compact disc, with the information accessible by microcomputer. Hand-held computers and optical scanners allow paperless collection of field data. Epidemiological analysis and data presentation is easily done with software packages, some of which are in the public domain. However, there are limitations in the use of computers for any epidemiological research. Investment of time is required to learn the use of a computer. Care needs to be taken to ensure accurate data entry, and correct choice has to be made of methods for subsequent statistical analysis. Microcomputers are valuable as labour saving devices, but cannot replace proper planning, execution and appropriate data analysis in epidemiological research in occupational health.
A pilot PACS project, named KIDS, has been running in Kyoto University Hospital. The purpose of the system is to establish a small PACS that includes all digital imaging modalities and to evaluate it. The project has been continued from the first phase (KIDS-1) to the second phase (KIDS-2). In the first phase, a small-scale PACS was developed. In the second phase, the expansion of coverage of modalities and completion of the image database was intended. At present, the database contains image data of 16264 patients amounting to 150 Gbytes. Simulation of the retrieval process to the database shows that 154.3 s per patient is required for retrieving his/her entire image data. This calculated value is close to the actual time.
A new technique for the three-dimensional recording of a person's mandibular movement is described. A small and harmless radioactive source is fixed on the patient's skin at the point of interest or sealed in a tooth cavity. Using the proper collimation, the motion of the point source is recorded via a gamma camera and minicomputer. Long-term storage on a magnetic device offers playback, slow motion facilities, and data analysis through the use of sophisticated computer languages. Simultaneous recordings using two cameras, or postsynchronization of two different views of an experiment, enable the three-dimensional restitution of mandibular movements. Superimposition of a grid of radioactive spots spaced at measured intervals during the recording permits a straightforward calibration of the patient's motion. Multiple sources in a single experiment may be recorded to describe the displacement of several points of interest. This method, derived from nuclear medicine techniques, offers a powerful tool of general interest for the tracking of dynamic events in many fields of dentistry such as temporomandibular joint dysfunction and prosthetic restorative techniques. Further considerations on our experimental settings and results will be published in part II.
Problems with picture archiving and communication systems (PACS) are focused and an off-line PACS of practical value is proposed in this paper. This system is based on the personal database where each patient has his/her own recording medium. This medium files all medical information as well as images of value, and is carried with a patient through hospital. Advantages over the conventional or on-line PACS communicating through a network are discussed and a possibility of practical use is analysed showing a prototype system. The biggest advantage of this system is quick and easy access to the images of concern and a small amount of cost for initial investment. It is also pointed out that the format of the data recording on the disk has to be standardized so that this system could be used for a medical care system over a wide area.