Quantification of the magnetic dust deposition in the magnetopneumographic diagnostic of the human respiratory tract

With the help of the SQUID magnetometric system the non-invasive magnetopneumographic quantification measurements were performed. Using groups of samples, models and tested persons, the remanent magnetic induction Br and relaxation curves of the most important contaminating powdered ferri- and ferromagnetic materials (PFM) were measured. The influence of the affecting physiological processes in the organism and some other factors cause the change of the relaxation process with a decay of Br. By means of the several compensations the measured data were corrected directly in the computer program. The most important information for the clinical practice of the diagnostic and the treatment of specific respiratory diseases (pneumoconiosis, etc.) is the amount and distribution of the contaminating PFM in the human respiratory tract. With the help of a unique SQUID magnetometric system the magnetopneumographic investigation of the specific PFM, such as Fe, Co, Ni or some oxides, was accomplished (1). This method is based on the measurement of Br upon the human chest after magnetising the thorax in the static field with the magnetic induction Ba. The value of Br is essentially proportional to the amount of the deposited PFM. The healthy organism reacts immediately with its defence mechanisms for all these contaminating elements. In the upper respiratory airways it is mostly the stimulation of the respiratory cycle like deepening of the breath, increasing the velocity of ventilation until the process of coughing. In the lower airways the PFM are transported outside the body with the help of ciliary beating and mucus flow. The most complicated defence system is activated in the alveolar area of the lung tissue. The clearance mechanism is based on the activity of the phagolysosomes in the alveolar macrophages (2, 3). Therefore, the majority of the magnetised particles are in continual movement what influences Br and leads to the decreasing of the measured signal. It is known as the relaxation process. 2. Subject and Methods It generally holds, that the smaller is the diameter of the particle, the deeper it penetrates into the respiratory system. The particles with the geometric diameter less than 5 µm (4) penetrate into the alveolar system and can deposit there. Bigger ones (up to 20 µm) settle in the lower airways and the particles of PFM with the diameter above 20 µm remain in the upper airways and the trachea.