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M M Frost

Publications and source records attributed to M M Frost.

13 recordsLinked to original sources
PubMed1996

A cost-analysis of computed radiography and picture archiving and communication systems in portable radiography.

A total of 40,000 portable examinations are performed each year at Shands Hospital (Gainesville, FL), a 570-bed teaching hospital. Radiographs are obtained using a screen-film combination with the films digitized for transmission to displays in four intensive care units. A cost-analysis of replacing screen-film with computed radiography (CR) integrated into a filmless picture archiving and communication system (PACS) network was performed. Equipment requirements included two CR units, three high-resolution dual monitor displays, and an archive to store 3 months of image data. The capital costs were amortized over a 5-year period. Capital and operating costs of the proposed expansion to the existing PACS network, together with anticipated cost savings, were determined. The maximum data transfer rate for portable examinations was 150 MByte per hour and approximately 400 GByte of image data are generated each year. These figures were used to determine the hardware requirements for handling the acquisition, transfer, and display of the images. Annual costs of the proposed expansion were about $220,000. Cost savings were achieved by elimination of film, including its handling by technologists/library clerks, and amounted to about $200,000 per year.

Adult↗
PubMed1996

Picture archiving and communication system bandwidth and storage requirements.

The purpose of this work was to determine the requirements for image storage and network bandwidth for a total digital department in a moderate sized academic radiology department. Data from the radiology information system was combined with image production information to produce a model of image acquisition. Destinations of images to reading rooms were studied to determine the final distributions of film. All findings were used to model the flow of data that would be expected if the images in the department were completely digital. Using today's standards, the department would produce approximately 15.7 Gbytes of data per day or 3.5 Tbytes of data per year if all acquisitions were digital. The peak acquisition rate would be 1.8 Gbytes per hour with a sustained rate greater than 1 Gbyte per hour for most of the working day. The anticipated bandwidth for the total digital department exceeded the capabilities of the existing picture archiving and communication system equipment. A distributed networked archive solution was shown to optimize access to images by radiologists and referring clinicians.

Computer Storage Devices↗
PubMed1996

Computed radiography and film digitizer inputs to an intensive care unit teleradiology system: an image quality comparison.

RATIONALE AND OBJECTIVES: We compared computed radiography (CR) with a film digitizer as an image input device for transmitting radiographs to intensive care unit (ICU) displays. METHODS: Limiting spatial resolution and low-contrast detectability performance were determined for a 600-speed screen-film combination and CR films. The same image data were transmitted to ICU displays directly from the CR or by digitizing the conventional film. RESULTS: CR resolution ranged from 2.5 to 3 line pairs per millimeter (Ip/ mm) depending on cassette size. Display station resolution for the CR image data was 1.5-1.9 lp/mm, but improved resolution could be achieved using display magnification modes. Film digitization resulted in a loss of resolution. Direct transmission of CR image data to display stations gave low-contrast detectability similar to that obtained with CR film. CONCLUSION: ICU teleradiology displays that use CR, rather than film digitizers, offer improved image quality and superior operational efficiency.

Intensive Care Units↗
PubMed1992

Evaluation of requirements and planning for picture archiving and communication systems.

Successful implementation of a picture archiving and communication system (PACS) requires extensive planning and the input of the users in the planning and evaluation stages. System design is conducted in nine stages: systems analysis, stages 1-4; system design, stages 5 and 6; and system implementation, stages 7-9. Users of the PACS are actively involved in systems analysis. At stage 1, problems are identified, project scope is defined, and whether the problems can be successfully addressed with a PACS is determined. If the project is feasible, current systems are studied at stage 2. Data are collected on the volume of image data to be transmitted, stored, retrieved, and displayed; distribution of imaging through the day; radiologists' reading patterns and volumes; job functions of technologists; characteristics of images to be included; types of equipment to be interfaced; physical placement of cables, connections, and equipment; and operational restrictions. All these data and more are used in stage 3 to specify requirements of the PACS. Rigorous specifications are needed to ensure that the final system performs at the desired level. At stage 4, users evaluate alternative solutions to problems. Although consultants and equipment manufacturers do much of the design, implementation, and installation, users must understand project scope and limitations of the technology and must ultimately be responsible for planning a system that meets their needs.

Cluster Analysis↗
PubMed1992

Image archival technologies.

A typical radiology department can create many gigabytes of image data per day and as much as 1 terabyte of data per year. Archiving and accessing this much data are substantial problems. One solution is data compression, which decreases data storage requirements and increases the rate of data transfer; however, standards are not yet available. Other solutions involve improvements in archival media. Jukebox subsystems allow automated access to multiple units. Digital magnetic tape, the standard medium, can store large amounts of information and enables easy updates or replacements; more practical technologies have been introduced in recent years. Digital videotape allows storage of digital video data and features a high rate of data transfer. Optical disks, now the preferred permanent archival medium, have a large storage capacity and provide excellent long-term stability. Optical tape is also being investigated as a solution to the archiving dilemma. Which technology to choose depends on many factors, including needs of the institution and the cost, stability, transfer time, and storage capacity of the system.

Computer Storage Devices↗
PubMed1987

Second stage tumor promoters: differences in biological potency and phorbol ester receptor affinity in C6 cells.

We have shown that the second stage tumor promoters mezerein (MEZ) and phorbol 12-retinoate 13-acetate (PRA) inhibit the gluccocorticoid-induced increase in glycerol phosphate dehydrogenase (GPDH) activity in C6 rat glioma cells with ED 50-values of 3.9 and 2.9 nM, respectively. Phorbol 12-myristate 13-acetate (PMA) was 10-fold less potent. MEZ was likewise more potent than PMA for inhibition of cAMP formation in response to isoproterenol. Binding competition studies using [3H]phorbol 12,13-dibutyrate ([3H]PDBu) yielded apparent Ki-values for MEZ and PRA of 50-70 nM. The large difference between the biological potencies of MEZ and PRA and their affinity for the major phorbol ester receptor suggest they may be acting through a more complicated mechanism in these cells.

Animals↗
PubMed1982

Digital subtraction angiography of peripheral vascular bypass procedures.

Without premedication or special preparation, digital video subtraction angiography, also known as photoelectronic intravenous angiography, was effectively used for evaluating patients who had undergone peripheral vascular reconstructive procedures. Thirty-eight studies in 20 patients were performed using computer contrast enhancement after an intravenous injection. Patency of arterial grafts was thereby evaluated, thus obviating further routine angiography. Graft patency, even of small complex graft sites, was easily recognized. Occlusions were also readily identified. Patient acceptance was excellent since the procedure is almost painless and can be done on an outpatient basis. The technique is fast, safe, and less expensive than routine angiography.

Angiography↗
PubMed1981

Digital video subtraction angiography of renal vascular abnormalities.

A digital subtraction system for performing intravenous angiography has been developed and applied to the diagnosis of renal vascular abnormalities. A total of 35 patients underwent 39 intravenous angiographic examinations for a variety of renal-related clinical indications. Satisfactory examinations were achieved in 36 cases (92%) with a high degree of diagnostic accuracy. Digital video subtraction angiography is an outpatient procedure that is accurate, safe, and inexpensive to perform.

Adult↗
PubMed1980

Intravenous angiography using digital video subtraction: x-ray imaging system.

An x-ray imaging system, using digital subtraction techniques, has been developed. The system requires: (1) high output generation equipment; (2) an image intensifier capable of receiving high output exposures, 1 mR (2.58 X 10(-7) C/kg) at the face of the intensifier, without loss of either contrast or resolution; (3) a precision digital video camera; (4) processing computer with sufficient storage capacity; and (5) digital image storage. With this system it is possible to visualize the major arteries after intravenous contrast injection. The system, angiography technique, and early results are described.

Angiography↗
PubMed1980

Intravenous angiography using digital video subtraction: intravenous cervicocerebrovascular angiography.

The clinical application of intravenous angiography to study the cervicocerebrovascular system using the digital video subtraction system described in a companion article is reported. About 0.75 ml/kg of a standard 76% iodine contrast solution is injected into an antecubital vein using a power injector. Then 15-20 exposures of the head and neck region at a 1/sec rate are made on the image intensifier. The images are recorded by a high performance video system and the output signal is digitized for subsequent computer manipulation. The subtraction images of these vessels produced by the computer show the vessels clearly, even though they contain very low concentrations of contrast media. Standard exposure factors of 75-80 kVp, 9-10 msec at 800-1,000 mA are used. Clinically pertinent features of the data alteration and flow through the system and the step-by-step computer procedures used to achieve and analyze the various forms of subtracted images are described. Five experimental and clinical cases demonstrate appropriate applications to cervicocerebrovascular disease: (1) evaluating the effects of surgical and medical therapy on atherosclerosis; (2) providing a screening angiographic test for patients with asymptomatic bruits and/or positive noninvasive studies; (3) evaluating patients who have significant generalized vascular disease either precluding or presenting hazardous contraindications to transarterial catheterization; (4) evaluating significantly aged patients in whom standard angiography has higher risk; and (5) evaluating currently asymptomatic patients who are medically at higher risk for developing atherosclerotic lesions. Numerous examples of the various types of image manipulations are presented: (1) linear subtraction; (2) logarithmic subtraction; (3) alterations of electronic contrast enhancement (map slope); (4) the usefulness of a series of angiographic images; and (5) the importance of multiple projections with this technique.

Aged↗
PubMedDate not supplied

Picture archiving and communications systems (PACS).

Although there has been a recent increase in interest in picture archiving and communications systems (PACS) topics, little has been published to assist the non-technical person in understanding the complexities of the technologies required for a PACS implementation. This issue of Current Problems in Radiology defines each PACS component and explains why each is important in a system design. PACS installations at the University of Florida are used as examples to tie the concepts together. The infrastructure required for PACS consists of the information system interfaces, networks, and databases. Information system interfaces guarantee consistent patient data across all platforms and reduce labor requirements by eliminating duplicate data entry. Data networks move information from the originating location to users around the hospital, clinic, campus, city, or world. In the PACS environment, the data consist of patient and study information as well as images and information about these images. Databases organize the data from multiple sources into a coherent package that can be queried for many different purposes, such as retrieving images, reviewing patient and study information, studying practice statistics, and performing outcomes analysis. PACS components consist of acquisition nodes, archives, and output devices. Acquisition nodes may include "digital modalities" such as CT, MRI, nuclear medicine, and computed radiography (CR), along with devices to convert from analog to digital, such as digitizers and frame grabbers. Options for archives are discussed along with configuration schemes. Output devices include both hard copy (film and paper prints) and soft copy (workstations for display and diagnosis). Finally, a description of the PACS installations at the University of Florida is presented, with comments on some of the difficulties and complexities encountered. A discussion of the cost and benefits of PACS is included, along with a forecast of the future of PACS.

Computer Systems↗