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Magnetism in Medicine: Old Problems and New Trendsтезисы доклада
- Автор: Koksharov Yu A.
- Сборник: IBCM 2023. Book of Abstracts
- Тезисы
- Год издания: 2023
- Место издания: Светлогорск, Россия
- Первая страница: 22
- Последняя страница: 22
- Аннотация: Since ancient times, the magnetic field has inspired attempts to apply it in medicine. All humanbeings are constantly exposed to the Earth's magnetic field, but, as a rule, are unaware of its existence.Routine use of magnets for the whole body with a strength of up to 1.5 T in clinical MRI began in theearly 1980s and introduced a new degree of exposure to magnetic fields on humans [1].Hundreds of studies have shown that magnetic fields can affect various systems of the humanbody and that biomagnetic effects include changes in reactions of cells to various external influences[2]. However, the effect of the magnetic field on biological systems still arouses suspicion amongmany physicists, as well as among the medical community, since some common problems have notyet been satisfactorily solved. 1) Scientific reports contain many, at first glance, contradictory results.2) The underlying mechanisms of biomagnetic effects remain elusive. 3) There are some strangefeatures of these effects from the point of view of physics, for example, cells can react to the influx ofenergy, which is low compared to thermal energy (kT).The reasons for these difficulties are thefollowing: 1) Biomagnetic effects are rather weak, since there is little interaction between magneticfields and diamagnetic or paramagnetic substances of living bodies. 2) The systems of the human bodyare very complexes and biomagnetic reactions are very selective, they depend on the state of activityof cells at the time of the beginning of the field effect. 3) The most relevant field variable is not alwaysthe field strength. Depending on the type of the biomagnetic reaction the frequency, the switchingspeed or the field gradient can be the determining factors of the response.Water is an integral part of living organisms. The effect of magnetic field on water is still acontroversial issue. It has been shown that magnetic treatment of water using very weak magnets withstrong magnetic inhomogeneities (∇B~0.1 T m-1) accelerates the growth of nm-sized clusters. Theproblem is to explain how a magnetic field influences nucleation [3].Nevertheless, despite the theoretical difficulties there are modern approved medical techniquesusing magnetic phenomena. Most of them can be grouped into the following types: (1) Magnetic fieldsare used indirectly to control (move) ferromagnetic (nano)materials or devices in the body. There isconsiderable interest in magnetic manipulation systems for current and future minimally invasivemedical applications, including direct drug delivery systems based on nanotechnology. (2) Timevarying magnetic fields produce electric currents in the body. The well-known application of this typeis magnetic hyperthermia. (3) Static or slowly changing magnetic fields are measured with very highsensitivity and accuracy to study electrical activity in the human body (for example, amagnetoencephalogram of the brain). (4) Magnetic tomography methods make a breakthrough indiagnostics. The most well-known method is the MRI based on the nuclear magnetic resonance.However, other types of magnetic tomography based on the electron paramagnetic resonance orsuperparamagnetism of nanoparticles are also actively developing.The potentially harmful nature of electromagnetic fields and static magnetic fields has becomea major problem in recent years. Identification and prevention of possible harmful effects oftechnogenic magnetic fields is also a modern trend of the topic under consideration.[1] W.Andrä and H.Nowak (Eds.) "Magnetism in Medicine: A Handbook" Willey-VCH (2007)[2] X.Zhang, K.Yarema, A.Xu (Eds.) “Biological Effects of Static Magnetic Fields” Springer (2017)[3] J.M.D.Coey “Philosophical Magazine” 92, 3857 (2012)
- Добавил в систему: Кокшаров Юрий Алексеевич