The dissertation is devoted to the decision of the actual scientific and applied problem of research of information and measuring systems (IMS) of biomedical application and methods of classification of biomedical data, their improvement and completion for certification and introduction in medical practice.
In the dissertation work a number of results on development and improvement of biomedical IMS based on superconductive SQUID-magnetometers are received. For the first time, a method of calibration of the SQUID-magnetometric IMS was developed and its calibration was performed using a calibrated measure of magnetic induction (MMI), which allowed to reliably estimate the metrological parameters of measuring channels of different types (relaxation and direct current). The test procedure of the 9- channel cardiomagnetic scanner was also improved, which allowed to assess its compliance with the requirements of the technical regulations for medical devices. Calibration of several samples of SQUID magnetometers was performed using the measure of magnetic induction.
For the first time, an analytical model of the magnetization system of the apparatus for low-frequency magnetic therapy was developed, which allowed to create a 3-component orthogonal magnetic field with a given size and homogeneity, the possibility of placing the whole patient's body in the treatment chamber at minimum weight and size of magnetization coils.
The method of classification of biomedical data have been improved by rejecting non-informative magnetocardiographic (MCG), biochemical and other parameters based on a series of multidimensional LDA tests. This allowed achieve the accuracy of classification for 2 groups of patients in the range of 84–90% and the average accuracy for 4 groups of 81.3% (specificity 100%, sensitivity to MI – 81%, myocarditis – 68.8%, coronary arthery disease – 66.7%). Thus, in the classification of two groups, accuracy is sufficient for implementation in medical practice, and in the classification of 4 groups - not enough to detect coronary heart disease and myocarditis.
The method of classification of biomedical data has been improved by rejecting non-informative magnetocardiographic (MCG), biochemical and other parameters based on a series of multidimensional LDA tests. This allowed to achieve the accuracy of classification for 2 groups of patients and.
In addition, a method for calculating the working area of magnetic applicators have been further developed based on experimental measurements of the magnetic field in the axial plane and calculation magnetic field and gradient coverage diagrams. This made it possible to accurately calculate the position and size of the working area of the applicator. It was confirmed that the applicator creates a field gradient of 1.4 mT/mm at a distance of 50 mm from the work surface, and 3.6 mT/mm at a distance of 30 mm, which is sufficient accumulation of magnetic nanoparticles (MNP) in the body of laboratory animals of medium size (rabbits).
Also, for the first time, the results of experimental studies of MNP using SQUID saseptometric IMS were obtained, in particular, evaluation of the effect of particle size, concentration and coating typeon the signal amplitude was evaluated. Experimental studies of Fe2O3 and Fe3O4 MNP were performed. The optimized frequency band of magnetization of nanoparticles in which the maximum signal is observed and the concentration calibration was performed for solutions of MNP Fe2O3 and Fe3O4 in gelatin and heptane.
Studies of stem sells cultures with MNP Fe2O3, laboratory animals (rabbits, rats) and their isolated organs have also been performed, which have shown that this information and measuring system is suitable for studying the distribution of MNPs and their composites with drugs in the body of laboratory animals, in particular for tumor models and magnetic applicators.
The design, operational, technological and other technical documentation for a number of samples of MCG systems and the "TURBOMAG" device were developed and improved. Certification of the device "TURBOMAG" (2010), verification of MMI (2014) and tests of the MCG system in SE "Ukrmetrteststandard" (2016) were performed. The "TURBOMAG" magnetictherapy device operates at the Institute of Clinical Medicine (2010), a 4-channel MCG system at the Main Military Clinical Hospital (2010), and a 9-channel cardiomagnetic scanner at the People's Republic of China and the United Kingdom (2016–2020). Part of the work was performed within the framework of the state order of the Ministry of Education and Science of Ukraine and Science and Technology Center in Ukraine (STCU) projects 3074, 4719, and Р624. 4 certificates on the implementation of the results of the dissertation research were obtained.
Keywords: biomedical equipment, information-measuring system, magnetic therapy, magnetic applicator, SQUID magnetometer, decision-making rule, classification, calibration, certification.
