Optical and laser diagnostics
Medical diagnostics based on laser spectroscopy has been an active field at Lund University since the field was initiated. Fluorescence spectroscopy to identify malignant tumours was first done in Lund and Santa Barbara, California, and the first reported time-resolved transillumination imaging was conducted in Lund. Both these techniques have attracted extensive interest world-wide and resulted in instrument commercially available to the benefit of patients. The group in Lund has also performed important work in the development of photodynamic therapy in the management of malignant tumours. Another project is based on time-resolved NIR spectroscopy of turbid media, such as tissue. Unique possibilities for tumour diagnostics are foreseen with the use of smart probe molecules resulting from progresses in the gene identification. Tomographic reconstruction algorithms for optical tomography require advanced signal analysis. Such development requires the Alliance competence.
Presently we are developing a concept of photodynamic therapy with individual feedback control to treat tumours thicker than a few millimetres. This requires interstital light delivery, through optical fibres inserted into the lesion to be treated. Precise dosimetry calculations and placement of the optical fibres are required for this treatment. The fibres positions will be confirmed with ultrasound or MR guidance.
Extreme low-dose radiation technology
Currently, a facility for extreme low-dose irradiation of living cells is implemented. It is based on a new technique to extract single MeV ions from the accelerator system, direct them towards chosen cells in culture and thus expose them to a well known dose (one or a few ions). The technique opens up new fields of irradiation research on a cellular level, important both for the basic understanding of radiation protection and for radiation therapy, and could lead to more precise and selective methods for patient treatment. The competence within the Alliance could contribute substantially with technique for automatic identification, adaptive pattern recognition, and mathematical modelling of processes occurring at beam damage in living matter.
Ultrasound diagnostics and technology
The ultrasound transducer is probably the most important component of a diagnostic ultrasound system. The achievable quality of the recorded ultrasound image is established by the quality of the transducer. Our research group has long experience and know-how in ultrasound transducer design and manufacturing. Today most electronic array transducers are manufactured from piezoelectric ceramic slabs, where a thousand individual elements are created by repeated cuts in the slab by a 20 µm wide diamond saw-blade. The slab may easily crack, and the resulting low yield makes high-frequency ultrasound array transducers frightfully expensive. The problem will be even worse when the number of transducer elements has to increase for 3D-imaging. Ultrasound can also be used for blood separation with applications to stem cell separation, dialysis, and therapeutic blood treatment.
Magnetic resonance imaging
A key interest in functional Magnetic Resonance Imaging research concerns quantification of physiological parameters from image information. Prerequisits for quantification of important parameters such as macroscopic flow, microscopic flow (perfusion) and molecular diffusion are at hand, however the conversion from signal data to quantitative information is not trivial. Regarding flow, main issues concern the conversion of velocity-sensitive phase information to velocity values in the presence of non-linear signal background. Diffusion-sensitive MR signal information needs to be obtained in several geometrical directions and subsequently mathematically analyzed. The research is focused on pulse sequences for optimal signal retrieval for functional investigations and postprocessing routines converting signal information to quantitative physiologically relevant information.
Optimization of image based diagnostics
Due to the adverse effects of ionising radiation, the responsibility is to use radiation and radioactive tracers effectively: to obtain sufficient information at an as low dose as possible. In spite of the long use of e.g. diagnostic X-rays even today the choice of technical parameters in the imaging process is largely based on experience rather than scientific knowledge. New techniques for digital imaging is needed since optimal exposure conditions may differ considerably from those in conventional screen-film imaging. There are similar needs in nuclear medicine imaging (gamma cameras, SPECT, and PET) and when fused images are produced (PET-CT, PET-MR, SPECT-CT etc).
As described in most of the previous examples general problems concern image content and image/signal acquisition, handling, interpretation and presentation. Other modelling problems concern cell metabolism and degeneration, and neural activity. Mathematical and statistical methods, inverse problems, estimation and detection theory and different approaches to time-frequency analysis are the main tools.
Mathematical image/Signal processing, Learning and pattern recognition
Medical diagnosis, e.g. of cancer, neurodegenerative, cardiovascular, and obstructive diseases, are increasingly based on computer assisted human analysis of image data from various sources (MR, Ultrasound, SPECT, PET). Improved quality and efficient handling of patients can be achieved through automatic analysis of such data. General methods, like automatic classification, Bayesian learning algorithms, pattern analysis, and data reduction, are essential in many medical disciplines and issues. Successful use of these techniques could in the end result in novel practices and commercialisation. Besides these practical consequences, the mathematical tools contribute to better understanding of the physical and biological processes.