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Dipartimento di Fisica - Politecnico di Milano

3 - Photonics for health, food and cultural heritage

The research ranges in various fields of application of laser spectroscopy, with particular interest in the issues of medical diagnostics and molecular biology. The common denominator of all the methods of investigation is the development and use of instruments to measure the light with high temporal resolution. For fluorescence measurements, systems have been made to count single photons with picosecond time resolution: they are currently applied to study selective portions of the hybridization of RNA labelled with fluorochromes that can be activated (molecular beacons). The extension of fluorescence spectroscopy to imaging systems has allowed designing systems that implement the Fluorescence Lifetime Imaging (FLIM) technique. This technique allows measuring the space map of the decay time of fluorescence in a sample. The FLIM technique has proven very effective for the diagnosis of cancer both in experimental oncology (laboratory animals) and in clinical trials (patients).

Familiarity with the problems of medical diagnosis using optical techniques with high temporal resolution allowed the research team to investigate the difficult problem of light propagation in highly diffusing media, what are the biological tissues. These studies have arisen important applications that have given to the research group a leadership position internationally in the absorption spectroscopy of biological tissues and in the development of noninvasive diagnostic methods. Among these, one of the most important is the realization of a system for performing optical mammography, that is breast images obtained without the use of ionizing radiation for the breast cancer detection. The use of laser light and tissue spectroscopy has also permitted the design systems for evaluating the content of haemoglobin in the tissues and the level of oxygenation. These researches are important for studies of physiology (muscle disorders, rehabilitation, etc.) and for the innovative field of "functional imaging". The functional imaging allows mapping the brain areas activated by stimuli (motor, cognitive, visual, etc.) and is of great importance for studies in neurophysiology.

Among the side activities that have originated from the expertise of spectroscopy developed for medical diagnosis, we mention the study of the state of conservation of cultural heritage and the evaluation of fruit quality by noninvasive optical methods.