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The mode analysis of signals in a multimodal shallow harmonic waveguide whose eigenfrequencies are equally spaced and finite can be performed by an optoelectronic device, of which the optical part uses the guide to sample the wave field at a number of sensors along its axis and the electronic part computes their fast Fourier transform. We illustrate this process with the Kravchuk transform.
We experimentally and theoretically studied the photon lifetime spectral distribution in two coherently coupled spherical microcavities of 3-16 microm diameter forming a photonic molecule, which shows a multipeak narrowband modal structure resulting from lifting of the mode degeneracy with respect to the azimuthal quantum number. The results demonstrate the feasibility of photonic molecules as a basis for a multichannel, wavelength-tunable optical delay-line device, which can be used for delay times in the range 10 ps to 1 ns.
We report a self-calibrating polarization analyzer fabricated with binary magneto-optic polarization rotators. The device automatically overcomes wavelength and temperature dependent inaccuracies and has impressive state of polarization and degree of polarization accuracies of 0.3 degrees and +/-0.5%, respectively, from 1460 to 1580 nm.
The effects of a micrometer-scale silicon ring resonator with a FWHM of 0.078 nm (9.6 GHz) on a nonreturn to zero amplitude-modulated optical signal with a modulation rate of 10 Gbps are experimentally investigated. By transmitting the optical signal through the device, significant spectral distortion and side band attenuation is introduced, as characterized by amplitude Bode plots, and a power penalty of 0.8 dB is observed. Carrier wavelengths within the transmission resonance, but detuned from the center wavelength, are investigated as well. Numerical simulations further support the experimental results.
Digital images generated by medical imaging form the basis for radiological diagnosis and surgical planning. Despite the advent of the DICOM 3.0 standard for medical image communication, widespread application of the existing information is often limited by incompatibility of the data formatting used by different equipment generations, and the manufacturer-specific standards employed. An exchange interface based on magneto optical discs has been developed to retrieve and present medical image data regardless of the technological hardware and the specific formats used. Specially adapted routines to retrieve the data first had to be developed. A modular program structure was used to allow flexibility in the implementation of further routines and other exchange media. Over 20,000 CT and MRI images including header information obtained from different General Electric and Siemens scanners were extracted successfully from MO discs. The image data were used for follow up and surgical planning and were transferred to a PAC-server. The interface proved reliable and easy to use. Support for further proprietary formats is currently being developed. The present exchange interface permits reliable retrieval of digital images for diagnostic and surgical planning purposes, regardless of the hardware generation and manufacturer-specific formats.
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This study assessed whether an intervention approach relying on auditory prompting delivered automatically through a portable device was effective to reduce tongue protrusion in a woman with severe to profound mental retardation. The device involved (a) an optic sensor, i.e., a miniphotocell kept under the lower lip with medical tape, (b) a small signal transmission box, and (c) a Walkman for presenting the prompts. Initially, the automatic prompting condition was combined with occasional praise from a research assistant for having the tongue in the mouth. Analysis showed that the occurrence of tongue protrusion dropped from about 65% of the observation time during the initial baseline to less than 5% through the intervention. The study lasted 4.5 mo.
Individual patient care and programme evaluation are pivotal for the success of antiretroviral treatment programmes in resource-limited countries. While computer-aided documentation and data storage are indispensable for any large programme, several important issues need to be addressed including which data are to be collected, who collects it and how it is entered into an electronic database. We describe a patient-monitoring approach, which uses patient encounter forms (in hybrid paper + electronic format) based on optical character recognition, piloted at Princess Marina Hospital in Gaborone, Botswana's first public highly active antiretroviral therapy (HAART) outpatient clinic. Our novel data capture approach collects "key" data for tracking patient and programme outcomes. It saves physician time and does not detract from clinical care.
The amount of data in the field of otorhinolaryngology has rapidly increased, in proportion to the growing number of patients. Medical imaging has especially expanded and the percentage of image data in all information is also large. Because the space to preserve image films is increasing, it is very important to preserve them and make them easily available. Therefore, we have established a graphic filling system for storing endoscopic and radiographic images on VHS video tape and magnet-optical disk (MOD), using a personal computer. The MOD filing system is useful for storing a large amount of medical records. The user can simultaneously see the text data and the picture image on a display, and thus this system can be utilized as a database for both decision making and medical research.
During evaluation of an optical to tactile conversion device, the Tactile Vision Substitution System (TVSS), a training program was developed to teach blind subjects to perceive visual information via the tactile modality. Tactile training paradigms which compensate for the limited resolution of the skin sense were applied to visual training procedures in a case of visual restoration following long term deprivation. Visual training in the visual restoration case also included electro-oculography biofeedback to facilitate oculomotor control and visual evoked potential evaluation for the objective assessment of visual function. The development of functional vision over an 11 month training period of a young girl who was form deprived form 3 months to 12 years is discussed.
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.
The implementation of portable record based on laser card technology is discussed in terms of data structures for quick access and software tools to reinforce security and confidentiality as required by medical data. Experimental results from a field test with a laser card technology are reviewed with regard to implementation in a large-scale and public information system. An efficient data structure is described for storage purposes, and some proposals are put forward to secure stored data.
An off-line network system of health and welfare for elderly people using optical memory cards has been established in Isehara city (Japan) since 1991. 2775 citizens have the cards and 24 offices have the terminals. It covers almost one third of people aged over 65 in Isehara city and almost all of the offices concerned with their health and welfare. About a half of holders use optical memory cards every time they visit these offices. The optical memory card holds data including basic data for health and welfare, health check data over 5 years, medical images with scripts and history of welfare services. All the data are used for medical care, health consultation and management of health and welfare services. A card can hold health and welfare data for a lifetime, and it is easy to expand the system. It has been a good experience for us, because the optical memory card system needs co-operation among citizens, medical association and local government, and the experience will help us to expand the system in the future.
The origination, development and application of a hypermedia system for use in the life sciences is described. Implemented in the Apple Macintosh HyperCard environment, the project has been designed to make use of commercially produced laser discs as visual archives and has included the production of authoring and navigational tools. We report here on our experience in authoring stacks for undergraduate teaching, monitoring of student use and assessment of effectiveness as a self-teaching resource. Future developments and applications within the biomedical sciences are discussed.
In this article the author explains the basic theory and practical applications of the latest advancement in imaging technology called fractal imaging. Fractal imaging is a unique way of compressing and storing images which has unlocked the door to the restrictions imposed by conventional imaging technology as regards storage and transmission of high quality images. The article outlines how this technology has been successfully applied by the creation of the first and only fractal photographic archival and retrieval system in Scotland, in the form of the George Washington Wilson collection comprising 44,000 images and associated text in only 450 megabytes (Mb) of disc space.
A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 microm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications.
An optical disk filing system is a promising new method to memorize the contents of medical records. However, due to problems of image quality, input speed and durability with the disk, this has not yet been put to practical use. In the present study the image quality of the laser disk system installed in our hospital were checked, and this system was thought to be useful to store discharge summary. We developed discharge summary management system by inputting into the optical disks the discharge summary written freely by doctors and the discharge abstract automatically formed by computer.
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