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Biomedical subjects

A W Templeton

Publications and source records attributed to A W Templeton.

At least 19 recordsLinked to original sources
PubMed1992

Computers in ultrasonic imaging.

This article describes the role of computers and digital electronics in state-of-the-art diagnostic ultrasound scanners. An overview of the computational requirements is provided, and limits on color flow image frame rates are discussed. The new scanner architectures emerging may be used to extend current limitations of ultrasonography, making features such as automatic phase aberration correction, speckle reduction, and tissue characterization available.

Humans↗
PubMed1992

Enhancement of storage phosphor plate images: a C-language program.

A C-language software program has been developed for emulating the image enhancement processing of a storage phosphor plate system. This software has been implemented on a VAX 3400 computer. There are 2,100 lines of C-language code in the program. There are seven parameters used to specify the degree of enhancement. The software is being implemented on a single accelerator board.

Algorithms↗
PubMed1992

Image calibration of laser digitizers, printers, and gray-scale displays.

Laser film digitizers, interactive gray-scale monitors, and laser film printers are necessary to transmit digital image information. These devices must be standardized so that hard- and soft-copy images are as similar as possible. Standardization of appropriate calibration procedures is necessary to attain this goal. Radiographs are converted into digital data representations by a laser film digitizer. These representations (and those obtained with other modalities) are transferred to a laser film printer or to an interactive monitor with gray-scale display. To obtain the best gray-level fidelity, printer output optical densities should be identical to those of the input film. Laser printers should be calibrated regularly to ensure uniform results. A gray-scale controller functions as an adjunct to the host computer and can automate the calibration process. Gray-scale controller functions may someday be incorporated into an accelerator or array-processor board.

Calibration↗
PubMed1991

Image data compression using a new floating-point digital signal processor.

A new dual-ported, floating-point, digital signal processor has been evaluated for compressing 512 and 1,024 digital radiographic images using a full-frame, two-dimensional, discrete cosine transform (2D-DCT). The floating point digital signal processor operates at 49.5 million floating point instructions per second (MFLOPS). The level of compression can be changed by varying four parameters in the lossy compression algorithm. Throughput times were measured for both 2D-DCT compression and decompression. For a 1,024 x 1,024 x 10-bit image with a compression ratio of 316:1, the throughput was 75.73 seconds (compression plus decompression throughput). For a digital fluorography 1,024 x 1,024 x 8-bit image and a compression ratio of 26:1, the total throughput time was 63.23 seconds. For a computed tomography image of 512 x 512 x 12 bits and a compression ratio of 10:1 the throughput time was 19.65 seconds.

Algorithms↗
PubMed1991

Wide area networks for teleradiology.

Teleradiology networks transmit digital radiographic images from one location to another. These networks are wide area networks. Teleradiology networks are used for diagnostic purposes and preview tasks. Wide area networks for teleradiology use public service switching. The use of fiber optics networks provide reduced costs and increased flexibility. An example is presented that compares the cost of teleradiology networks.

Computer Communication Networks↗
PubMed1991

State-of-the-art digital radiography.

Technologic advances in digital radiography have improved the ways in which radiographic images are acquired, displayed, transmitted, recorded, and archived. With computed radiography, performed with storage phosphor plates and interactive high-resolution workstations, radiation dose is reduced and repeat exposures necessitated due to technical errors are eliminated. Digital fluorography allows reductions in dose, procedure time, and film costs. These digital imaging modalities have been well accepted clinically and are equal in diagnostic accuracy to conventional methods. Teleradiology has advanced with the development of laser film digitization, fiberoptic networks, and dial-up circuit switching technology. Laser film printers yield improved hard copies of transmitted images, but further work is needed to faithfully reproduce the images displayed on high-resolution work-stations. Although the capacity for archiving digital image data has increased (260,000 examinations or 23,500 Gbytes can be stored in a six-unit optical disc library), higher capacity storage media are needed. Further technologic advances in the speed of image transmission and storage capacity are anticipated.

Humans↗
PubMed1990

Teleradiology: an assessment.

A teleradiology system acquires radiographic images at one location and transmits them to one or more remote sites, where they are displayed and/or converted to hard copy. These systems often employ wide area networks. Their goal is to provide improved radiologic services at all sites on the network. Experience in the use of teleradiology systems has demonstrated the need for a laser film digitizer, an optical disk, and a high-quality display and/or laser film printer at each site. Single-site hardware purchase costs average $196,000, plus an additional 20% for yearly network services. Hardware purchased for a consultation or central referral facility approximates $344,000.

Computer Communication Networks↗
PubMed1989

Digital imaging of the chest.

During the past several years, image acquisition in nuclear medicine, computed tomography, ultrasonography, subtraction angiography, and magnetic resonance has been by digitization. Despite these advances, research in the development of digital imaging in conventional radiography has lagged behind. Although studies with a variety of digital techniques have been carried out on several fronts, we still do not possess a method that has captured the imagination of the majority of radiologists and other physicians to a point where it could replace conventional screen-film imaging. This article reviews the current status and general principles of the technology, focusing on the four digital radiographic techniques that have shown the greatest promise - film digitization, an image intensifier - based system, photostimulable phosphor plates, and a scanned projection system. The physical aspects of each of the four systems and the clinical results that have been reported to date, as well as the advantages and disadvantages of each system, are presented.

Humans↗
PubMed1989

Digital venography of the lower extremity.

A digital 33-cm fluoroscopic system equipped with conventional spot-film and digital or video hard-copy capabilities was evaluated for its usefulness in diagnosing deep venous thrombosis of the lower extremities. The impact of different fluoroscopic field sizes, spatial resolution, and contrast variance was measured by using phantoms. The results indicate that the physical characteristics of the digital system are acceptable for lower-extremity venography. Digital fluoroscopic hard copy was compared with conventional spot films in 22 examinations. The digital examinations were as accurate as the conventional examinations. Procedure time, exposure to radiation, film costs, and repeated injections of contrast medium because of errors in exposure were reduced with the digital method. The need for extra technologists was eliminated. The advantages of digital radiographic displays, postprocessing, storage, and transmission were maximized. Digital fluoroscopic examinations were as accurate as conventional spot films and were found to have many advantages.

Fluoroscopy↗
PubMed1987

A digital radiology imaging system: description and clinical evaluation.

We have successfully interfaced an advanced microcomputer system to a 47-cm image intensifier for direct digital radiology. Our development effort has included the design and construction of hardware and the implementation of software. The system matrix (spatial resolution) is 1024 X 1024 and contrast resolution is 8 bits deep. A receiver-operator-characteristic analysis comparing conventional and digital laser chest radiographs for the detection of lung nodules demonstrated no statistical difference. Dosimetry measurements identified decreased patient dose. The intensifier-based digital imaging system is being increasingly used for a variety of examinations including IV pyelograms, all kinds of barium studies, and skeletal, trauma, and chest studies. Hard-copy laser-printed digital images with "bones black" are preferred by the radiology staff and have been well accepted by referring clinicians.

Evaluation Studies as Topic↗
PubMed1986

Estimating digital information throughput rates for radiology networks. A model.

The design and implementation of a digital radiology image management system requires the definition, evaluation, and comparison of appropriate measures of system performance. The mean throughput rate is an important measure of the actual performance of a finished system. The mean throughput rate identifies the transmission of digital information either in bits/second or tasks/second. It is dependent on software, database management, equipment interface designs, number of users and display stations, and communications media. The mean throughput rate can document resource allocation bottlenecks within a given system. A model for estimating the mean throughput rate and its application in helping us design our radiology digital image networks is described.

Electronic Data Processing↗
PubMed1986

Computer networks for image management in radiology: an overview.

Currently, images obtained from digital radiographic modalities are archived and managed as analog images recorded on radiographic film. An alternative for total image management is a computer-based digital network. General design considerations for a digital image network are reviewed, and estimates of important system parameters are determined.

Computers↗
PubMed1986

Digital image management: networking, display, and archiving.

The requirements for implementing a radiology imaging network are similar to those for local area networks now being designed for other purposes to manage large data films. A radiology department serving a 500-bed hospital generates about 927 megabytes of digitally formatted data per working day. These data are expected to be on line for the patient's hospitalization period. The retrieval rate of these data among the interactive diagnosis display stations requires data throughput rates of between 2 and 5 megabits per second. This throughput rate requires signaling rates of between 20 and 50 megabits per second. Analog hard-copy generation of the images on the network is required by the referring physician for selected images that support the consultation report. Digital laser recorders using paper may be quite satisfactory. Long-term archiving must be low in cost and requires a database scheme capable of managing more than a terabyte of image data. Radiology networks must be required to bridge with other hospital information systems.

Computers↗