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Biomedical subjects

N Pallikarakis

Publications and source records attributed to N Pallikarakis.

48 records · Page 3Linked to original sources
PubMedDate not supplied

Logarithmic amplifier for computed tomography tasks using fluoroscopic projections.

The image intensifier (II)-based imaging systems, as radiotherapy simulators or C-arm X-ray units, have also been used for image acquisition in computed tomography. When analogue-to-digital conversion is performed on the output signal of the television camera, the accuracy for low-amplitude video signals, corresponding to X-ray pathways crossing high attenuation structures, is limited. To deal with this lack of accuracy, we investigated the benefits of using a logarithmic amplifier (LOGAMP) inserted between the television camera output and the analogue-to-digital converter (ADC) in the image acquisition chain. Such a device was intended to provide better use of the available ADCs of a given resolution and actually to reduce the quantization noise. Simulated data were used in this study, and cases with and without logarithmic amplifier were compared. Based on the simulation results, we formulate requirements for several signal and acquisition system parameters where the use of such a circuit is recommended.

Amplifiers, Electronic↗
PubMedDate not supplied

Development of a new Clinical Engineering Management Tool & Information System (CLE-MANTIS).

The evolution of the field of biomedical technology has led to the diffusion of an impressive number of medical devices into healthcare institutions. In this environment, Clinical Engineering Departments (CEDs) are expanding their role in healthcare technology management, by changing their structure and introducing quality systems in order to improve their services and monitor the outcomes. In the framework of the national project BIOTECHNET II, a software tool for the management of biomedical technology, named CLE-MANTIS, has been developed, with the aim to assist CEDs in their tasks. CLE-MANTIS functions include the upkeep of an inventory, the support and monitoring of scheduled maintenance, corrective maintenance, vigilance, equipment acquisition and replacement, service contract management and user training. The system offers clinical engineers the possibility to monitor and evaluate the quality and cost-effectiveness of their departments through the monitoring of quality and cost indicators. This paper presents the main features and functions of the system.

Biomedical Engineering↗
PubMedDate not supplied

A study on the current situation in the biomedical technology and clinical engineering sector in Bulgaria--advances, trends and needs.

A survey of the clinical engineering sector in Bulgaria was carried out, within the context of the 1996 Phare Partnership Program, with the aim to provide a reflection of the current situation concerning the management of biomedical technology and investigate the relevant needs in hospitals. The survey was initiated by the Institute of Biomedical Technology (INBIT) in Patras, Greece, with the active support of national organizations, educational institutions and other parties that share involvement in the overall management of medical devices in Bulgaria. This paper summarizes the results of the survey, giving an insight into the situation in the field and providing the basis for a more thorough study on the Biomedical Technology and Clinical Engineering sectors in Bulgaria.

Biomedical Engineering↗
PubMedDate not supplied

A multiple projection method for digital tomosynthesis.

A new method of optimized efficiency for the retrospective reconstruction of tomograms is presented. The method has been developed for use with isocentric fluoroscopic units and is capable of performing digital tomosynthesis of anatomical planes of user selected orientation and distance from the isocenter. Optimization of efficiency has been achieved by segmenting the reconstruction process into discrete transformations that are specific to groups of pixels, rather than performing pixel by pixel operations. These involve a number of projections of the acquired image matrices as well as parallel translations and summing. Application of this method has resulted in a significant reduction of computing time. The proposed algorithm has been experimentally tested on a radiotherapy simulator unit with the use of a phantom and the obtained results are reported and discussed.

Algorithms↗
PubMedDate not supplied

A method for selective removal of out-of-plane structures in digital tomosynthesis.

The quality of the reconstructed images in Digital Tomosynthesis is often limited by the presence of artifacts due to blur from planes other than the fulcrum plane. A technique has been developed for the separation and subsequent removal of unrelated structures from the reconstructed plane. The method involves the reconstruction of the blur originating in user-selected "noisy" planes as it appears on the plane of interest. This is achieved by projecting the reconstructed images of the selected plane on the image formation plane for all viewing angles, and subsequently, synthesizing its blurred image on the plane of interest. There are no restrictions as to the identity of the planes to be removed. Reproduction of the noise is performed using the tomosynthesis algorithm itself, thus the technique can be modified to suit any reconstruction algorithm. The proposed technique was implemented on the Multiple Projection Algorithm and was experimentally evaluated using a radiotherapy simulator unit.

Algorithms↗
PubMedDate not supplied

Integrated software system for improving medical equipment management.

The evolution of biomedical technology has led to an extraordinary use of medical devices in health care delivery. During the last decade, clinical engineering departments (CEDs) turned toward computerization and application of specific software systems for medical equipment management in order to improve their services and monitor outcomes. Recently, much emphasis has been given to patient safety. Through its Medical Device Directives, the European Union has required all member nations to use a vigilance system to prevent the reoccurrence of adverse events that could lead to injuries or death of patients or personnel as a result of equipment malfunction or improper use. The World Health Organization also has made this issue a high priority and has prepared a number of actions and recommendations. In the present workplace, a new integrated, Windows-oriented system is proposed, addressing all tasks of CEDs but also offering a global approach to their management needs, including vigilance. The system architecture is based on a star model, consisting of a central core module and peripheral units. Its development has been based on the integration of 3 software modules, each one addressing specific predefined tasks. The main features of this system include equipment acquisition and replacement management, inventory archiving and monitoring, follow up on scheduled maintenance, corrective maintenance, user training, data analysis, and reports. It also incorporates vigilance monitoring and information exchange for adverse events, together with a specific application for quality-control procedures. The system offers clinical engineers the ability to monitor and evaluate the quality and cost-effectiveness of the service provided by means of quality and cost indicators. Particular emphasis has been placed on the use of harmonized standards with regard to medical device nomenclature and classification. The system's practical applications have been demonstrated through a pilot evaluation trial.

Database Management Systems↗
PubMedDate not supplied

An educational hypertext system supporting radiographic image quality.

Understanding the physical and technical factors affecting image characteristics is an essential learning task in the process of optimizing radiographic image quality. The goal of the present effort is the design of a stand-alone software application acting as an educational aid to radiology residents and radiographers. The application is organized in three modules, each one offering a different approach to the learning task. The core of the system is a hypertext database management system composed of text, digitized radiographs, graphics and animations. User orientation, linking, indexing, and annotation are some of the facilities offered in pursuing topics of interest.

Computer Graphics↗
PubMedDate not supplied

A learning tool in medical imaging: using procedure graphs in radiographic process simulation.

Teaching the procedural elements of imaging protocols and understanding the interrelationships and interdependencies of diagnostic X-ray system parameters and their effects on image quality, are among the main objectives of medical imaging training programs. A teaching tool is designed and implemented to support these goals. Tool design is influenced by hybrid learning system architectures and it is based on a graph approach, which is described. Implementation is carried out using a hypermedia development environment (Toolbook) coupled with a database (Paradox). The core of the system is an attributed priority graph, capable of supporting the organization of the domain knowledge, monitoring of user-machine interaction and managing the user-system dialogue. Use of this approach resulted in an interactive simulation tool, which provides computer aided learning support, to radiology related personnel, such as radiologists and radiographers. The potential value of the tool is not restricted only to didactic tasks, but may include trouble-shooting and documentation.

Computer Simulation↗
PubMedDate not supplied

EDI system definition for a European medical device vigilance system.

EDI is expected to be the dominant form of business communication between organizations moving to the Electronic Commerce era of 2000. The healthcare sector is already using EDI in the hospital supply function as well as in the clinical area and the reimbursement process. In this paper, we examine the use of EDI in the healthcare administration sector and more specifically its application to the Medical Device Vigilance System. Firstly, the potential of this approach is examined, followed by the definition of the EDI System Reference Model and the specification of the required system architecture. Each of the architecture's components are then explained in more detail, followed by the most important implementation options relating to them.

Computer Communication Networks↗
PubMedDate not supplied

A layered architecture for computer-based simulation supporting skills learning: an X-ray imaging paradigm.

Simulation is characterized by strong learning potential, providing the basis for a new category of systems, the simulation-based learning systems. To strengthen the learning potential of these systems, models are needed not only of the actual system being imitated, but also of the operational expertise required to carry out manipulations of the simulated system, inherently linked to learning. In this paper, an architecture is reported aimed at supporting the organization of multimodal simulation resources to induce skills learning. This architecture is based on distinct layers, allowing independent representation of learning and simulation components. Its applicability has been demonstrated by means of a paradigm, including simulation of X-ray imaging procedure, as well as authoring of learning scenarios pertaining to such procedures.

Algorithms↗
PubMedDate not supplied

Computer assisted process management for health care: the IBIS tool.

IBIS is a broad range informatics tool, which can provide essential assistance to users during quality development projects in the health care environment. It can be used to set up a preliminary process model and specify variable and their interrelationships; the system propagates various quality related effects through the process structure, in a bottom up fashion, by linking quality indices to outcomes, repetitively, until arriving at the final outcome, at the top. An incorporated interactive browser is used to simulate the running process, to test and evaluate it, though a cause--effect interaction on intermediate or final outcomes. The tool provides guided support throughout the quality development procedure and during the continuous improvement process. At the same time, it constitutes an effective training tool on the principles of quality work. Additionally, IBIS can be used for the quality system's documentation, by means of a multimedia presentation, incorporating descriptive text, images and graphical displays, video sequences and sound.

Decision Support Systems, Management↗