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From the earliest days of its existence, the Institute has been involved in medical research. Much of this has been possible because of the concentration of specialist physical instrumentation and expertise which members of the Institute have developed and applied to the diagnosis and treatment of disease. In 1955 nuclear physicists first irradiated a patient with gamma radiation produced by the betatron and in the next 20 years about 2000 cancer patients were treated using this instrument. During this period many new instruments were developed and constructed for use in diagnosis with radioisotopes, including body scintillation counting and special instruments for liver and kidney.

The research reactor TRIGA was used to produce radioisotopes such as radioactive fluorine and, later on, radioactive technetium and other artificial radioactive isotopes which allow rapid diagnosis of cancer, heart disease and other conditions. Much more recently, a method using neutrons for non-invasive treatment of malignant diseases (Boron Neutron Capture Therapy) is in the development stage. The aim of this method is the selective delivery of the isotope boron-10 into the tumour, using the "magic bullet" technique. Boron is coupled to an antibody, produced in the Institute, which is targeted specifically to the tumour cell surface. On irradiation with neutrons, an alpha particle is produced in situ, which destroys the malignant tisue.

Evolvement of research areas


HEALTH

The broad spread of analytical expertise in the Institute has enabled a number of environmental health problems to be tackled. For example, the world's second largest mining area for mercury is located near Idrija and water draining the cinnabar deposits is seriously contaminated. A major study of the uptake and distribution of mercury and other toxic elements in humans has been carried out, showing amongst other things, that selenium accumulates in tissues where there are high levels of mercury uptake. This work has been coupled with an occupational health survey.

In the middle of the seventies electron spin resonance was introduced as a method for investigating the basic characteristics of malignant tissues, the transport of substances (potential drugs) into tissues by liposomes, together with more basic investigations into the properties of cell membranes.

The existence of an active research programme involving nuclear magnetic resonance (NMR) has enabled NMR imaging to be introduced in Ljubljana as a non-invasive diagnostic tool for the early detection of arthritis and of muscular diseases, and for investigating the development of blood clots. There is promise that this technique may be uniquely useful for the early recognition of stroke-endangered persons and tumours in the brain. Alongside this, the growing requirement for more rapid, reliable and non-invasive diagnostic tools in medicine has stimulated the development by physicists here of positron-emission tomography based on multiwire chambers.

One of the important applications of the Institute's research into the characterization and function of proteolytic enzymes and their inhibitors has been the development and marketing, in collaboration with the KRKA pharmaceutical firm, of diagnostic kits for estimating proteinases and inhibitors in disease states. Stefin A, discovered in and named after the Institute, has been shown to be a significant factor in the prognosis of mammary gland cancer, allowing more selective programmes of chemotherapy to be designed.

In the active field of robotics in the Institute, basic research on the precise definition and measurement of the complex motion of human limbs has found applications in the computer aided technology for custom-made artificial limbs. This involves computer tomography of the joint, the design of prostheses using the mathematical model of an ideal joint and its subsequent production. A related study was dedicated to modelling the human knee joint. The robot moves the joint and measures its resistance while different malfunctions are stimulated. Such information is important for deciding the most effective surgical treatment.

Alongside this, the Biocybernetics Laboratory is concerned with the accurate control of human limb movement. To this end, the technology has been developed for fixing the electrodes of implantible stimulators to, for example, the peroneal nerve. Using multi-channel electrical stimulation, the aim is to control the gait and thus rehabilitate hemiplegic patients as well as treating circulatory diseases and assisting control of the pulmonary ventilation system. A variety of different stimulators are produced in the Laboratory to CE specifications and sold world-wide.

Medical diagnosis and decision making for appropriate treatment involves complex and sophisticated procedures, until recently the preserve of the human brain. The massive increase in the amount of relevant information, however, now makes it essential to call for computer-based decision making. The analysis of clinical databases and synthesis of medical knowledge has been addressed by developing specialised methods based on inductive machine learning, clustering, fuzzy sets, Bayesian classification and statistical methods. Such methods have been tested in the medical domain and used to support decision making for selected medical problems. In co-operation with medical doctors the following type of problem have been addressed: analyses of malignant cells in breast cancer, forecasting the outcome of severe head injuries, diagnosing coronary artery disease and sport injuries. In a further application, part of the Cardio project, an intelligent device for multi-channel, PC-based ECG signal acquisition and processing has been developed.


J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Telephone: +386 1 477 39 00, Fax: +386 1 251 93 85
info@ijs.si