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Biomedical subjects

T Groth

Publications and source records attributed to T Groth.

At least 145 records · Page 8Linked to original sources
PubMed1975

An off-line system for in-time analysis of cardiac catheterization data and for establishment of a cardiological database for retrospective studies.

The system described may be divided in two major parts: (i) automatic analysis of cardiac catheterization data running off-line on a Siemens 305 computer; (ii) storage and retrieval of the results from these analyses and additional data from related departments (thoracic surgery, internal medicine and clinical physiology) in a cardiological database on an IBM 370/155 computer. The first part is described with special regard to (i) operation and control during the phases of data collection, pre-processing, processing and storage of results; (ii) the presentation of the results in a complete and readable form and (iii) the modular design of the software. The results of an evaluation of the computer methods versus manual methods are also presented. The second part has been described with regard to the type of data entered in the cardiological database. The structure of the database and the programs used for storage and retrieval have not been described in detail in the present publication.

Analog-Digital Conversion↗
PubMed1975

Cell kinetic approach to optimising dose distribution in radiation therapy.

A simple tumour-cell radiation-response model was coupled to a dose-calculation routine and applied to a clinical situation in radiation therapy. The dose distributions resulting from various settings of two radiation fields, as well as the tumour response under various assumptions regarding sensitivity and distribution of tumour cells, were calculated automatically. The probability of zero surviving tumour cells after 30 fractions was taken as a measure of goodness of the dose distributions and was found to vary rather smoothly over the parameter intervals considered. For some parameters a distinct optimum was found, rather insensitive to different assumptions regarding cell response. A tolerance factor for healthy tissue, based on a dose-volume relationship, was also considered. It is concluded that a cell kinetic approach to automatic optimisation of field parameters in external radiation therapy might be realistic both from computional and economic points of view.

Cell Survival↗
PubMed1975

Errors and uncertainties in external radiation therapy. A system analysis with a cell kinetic model.

The relative importance of accurate knowledge and control of various biologic and physical factors in external radiation therapy was estimated with a simple cell kinetic treatment response model for a simulated tumour therapy situation. A set of parameter values was chosen for a reference case so that the calculated probability of zero surviving tumour cells was about 0.5. The parameters were varied, one at a time, over a range that was considered representative with respect to uncertainty in dose calculation, dose delivery and the description of the pertinent patient data. Also parameters in the cell kinetic model were varied. The calculations demonstrated a strong influence on the number of surviving cells from even moderate changes in the parameters which affect the tumour dose. Predictions with regard to curability are heavily dependent on the reliability of the biologic parameters in the model.

Cell Survival↗
PubMedDate not supplied

INFORM: development of information management and decision support systems for High Dependency Environments.

The long-term aim in the INFORM Project is to develop, evaluate and implement a new generation of Information Systems for hospital High Dependency Environments (HDE-Intensive Care Units, Neonatal Units, Burns Units. Operating and Recovery Rooms, and other specialised areas). The distinguishing feature of the HDE is the very large amount of data that is collected through monitors and paper records about the state of critically ill patients; this has made the role of the staff a technical one in addition to a caring one. The INFORM System will integrate Decision Support with on-line, off-line and observed patient data and, in addition, will incorporate and integrate unit management features. In the Exploratory Phase of the Project, functional requirements have been set out. These are based on four components: conceptual model of the HDE; evaluation of existing HDE Information Systems; development of a novel software architecture using a Knowledge-Based Systems (KBS) methodology, and based on a critical review of KBS applied to the HDE: monitoring of appropriate leading-edge technological developments. The conceptual model has two components: a patient-related information model, and a department-related cost model. The patient-related model is identifying key and difficult areas of decision making. A key aspect of INFORM is integration of clinical Decision Support for these areas into the Information System through a layered software architecture. The lower layers are concerned with monitoring and alarming and the higher levels with patient assessment and therapy planning. The functionality and interconnection of these layers are being determined.

Decision Support Systems, Management↗
PubMedDate not supplied

An interactive computer simulation program for the design of statistical control procedures in clinical chemistry.

A computer simulation program has been developed to aid in the design of statistical quality control procedures in clinical chemistry. This 'QC simulator' permits the user to study the effects of parameters in the analytical procedure (method standard deviation, components of variance, rounding of data) and parameters in the control procedure (choice of statistics, control limits, decision criteria, number of control observations). The performance of the control procedures being studied are characterized by their probability for ejection, estimated at several different levels of random and systematic error, and presented by plots of statistical power vs the size of the analytical errors. The relative performance of different control procedures can be compared based on these performance characteristics. Another important application of the program is in the design of control procedures to assure that a specified level of analytical quality is achieved in routine laboratory analyses. The utility of this interactive simulation tool is illustrated in two typical sample runs.

Chemistry, Clinical↗
PubMedDate not supplied

Computer simulation of fluid resuscitation in trauma. I. Description of an extensive pathophysiological model and its first validation.

Computer-based 'patient simulators' are of a potential value in diagnosis, monitoring and therapy of the severely ill patient with trauma. An extensive pathophysiological model is described and documented in full detail. The model makes it possible to calculate and predict clinically important state variables on the basis of fluid input and fluid losses. Sample runs are presented for illustrations in hemorrhage, fluid and salt loading.

Animals↗
PubMedDate not supplied

Knowledge-based systems in medicine--a Nordic research and development programme.

A Nordic research and development programme, 'KBS in Medicine' (KUSIN-MEDICINE), was run in 1986-89. Its main goal was to acquire an understanding of applying knowledge-based techniques in medicine and of the limitations of present-day artificial intelligence (AI) methodologies. The programme comprised four experimental installation sites (Tampere in Finland, Uppsala and Linköping in Sweden, and Aalborg in Denmark) each prototyping in one or more medical domains. The programme was financed by the Nordic Fund for Technological and Industrial Development, by national funds for applied research and by a number of industries. Prototype decision support systems were produced in the following domains: intensive care (Tampere, Uppsala, Linköping, Aalborg), clinical chemistry (Tampere, Uppsala) and clinical neurophysiology (Aalborg in collaboration with Turku and Uppsala). These served to transfer this technology to industry and helped to identify limitations of this technology.

Artificial Intelligence↗
PubMedDate not supplied

KBSIM: a system for interactive knowledge-based simulation.

The KBSIM system integrates quantitative simulation with symbolic reasoning techniques, under the control of a user interface management system, using a relational database management system for data storage and interprocess communication. The system stores and processes knowledge from three distinct knowledge domains, viz. (i) knowledge about the processes of the system under investigation, expressed in terms of a Continuous System Simulation Language (CSSL); (ii) heuristic knowledge on how to reach the goals of the simulation experiment, expressed in terms of a Rule Description Language (RDL); and (iii) knowledge about the requirements of the intended users, expressed in terms of a User Interface Description Language (UIDL). The user works in an interactive environment controlling the simulation course with use of a mouse and a large screen containing a set of 'live' charts and forms. The user is assisted by an embedded 'expert system' module continuously watching both the system's behavior and the user's action, and producing alerts, alarms, comments and advice. The system was developed on a Hewlett-Packard 9000/350 workstation under the HP-Unix and HP-Windows operating systems, using the MIMER database management system, and Fortran, Prolog/Lisp and C as implementation languages. The KBSIM system has great potentials for supporting problem solving, design of working procedures and teaching related to management of highly dynamic systems.

Artificial Intelligence↗
PubMedDate not supplied

The development of a multicenter database for reference values in clinical neurophysiology--principles and examples.

This paper describes the work undertaken to establish principles for the development of multicenter databases for reference values in clinical neurophysiology. The study was initiated because of interest of the involved laboratories in knowledge-based systems in electromyographic diagnosis, for which it was necessary to formalize the key concepts in the diagnostic process: diseases, pathophysiology and test results. The paper deals specifically with the structuring of results of motor and sensory nerve conduction studies.

Action Potentials↗
PubMedDate not supplied

KBSIM/FLUIDTHERAPY: a system for optimized design of fluid resuscitation in trauma.

An application of the KBSIM (Knowledge-Based SIMulation) system to the improved design of fluid resuscitation is described. The system integrates knowledge from three domains, viz. the pathophysiology of traumatized patients represented in a quantitative biodynamic model, the heuristics of fluid resuscitation of such patients as represented in 'production rules', and some 'metaknowledge' reflected in the design of a multi-window user interface. This technique of combining numerical simulation with symbolic reasoning has obvious advantages during the design process and in training, by giving the user a possibility to evaluate his measures by direct feedback from the system. This feature of the system to assist in evaluation of alternative resuscitation procedures should also be useful as a means for decision support.

Artificial Intelligence↗