The application of magnets in medicine

Homing pigeon enthusiasts know that if the birds are released hundreds of kilometers away, they will return to their nests. Why do pigeons have such good homing skills? Pigeons, it turns out, are sensitive to the Earth's magnetic field and can use variations in it to find their home. If you attach a magnet to the pigeon's head, the pigeon will get lost. Powerful electromagnetic interference can also disorient pigeons if they fly through radio towers.

In medicine, the use of nuclear magnetic resonance can diagnose abnormal tissues in the human body and determine the disease, which is the nuclear magnetic resonance imaging technology we are more familiar with, its basic principle is as follows: the nucleus has a positive charge, and spin motion. Normally, the spin axes of nuclear nuclei are arranged irregularly, but when they are placed in an external magnetic field, the spatial orientation of nuclear spin transitions from disorder to order.

The magnetization vector of spin system increases gradually from zero. When the system reaches equilibrium, the magnetization intensity reaches a stable value. If the nuclear spin system is subjected to an external action, such as radio-frequency excitation of the nucleus, the resonance effect can be caused. After the radio frequency pulse stops, the nucleus of the spin system has been intensified, can not maintain this state, will return to the original arrangement in the magnetic field, at the same time, the release of weak energy, become radio signals, the many signals are detected, and the space of the resolution, to get the nuclear distribution image in motion.

NMR is characterized by the fact that the flowing liquid does not generate a signal known as the flow effect or flow void effect. So blood vessels are off-white tubes, and blood is unsignaled black. This allows the blood vessels to easily separate from the soft tissue. The normal spinal cord is surrounded by cerebrospinal fluid, which is black, and has a white dural set off by fat, which makes the spinal cord appear as a white strong signal structure. Nuclear magnetic resonance has been used in imaging diagnosis of various systems throughout the body. The good effect is brain, its spinal cord, heart great blood vessels, joint bone, soft tissue and pelvic cavity. It can not only observe the anatomical changes of each chamber, great vessels and valves, but also make ventricular analysis for qualitative and semi-quantitative diagnosis. It can make multiple section maps with high spatial resolution, showing the full picture of the heart and the lesions, as well as the relationship with the surrounding structure, which is superior to other X-ray imaging, two-dimensional ultrasound, nuclide and CT examination.

Magnet is an ancient medicine in traditional Chinese medicine. Magnetic differences in different components of blood are used to separate red and white blood cells. In addition, the interaction between the magnetic field and the meridians of the human body can achieve magnetic therapy, which has a unique role in many aspects. There have been magnetic therapy pillow, magnetic therapy belt and other applications. Iron remover made of magnets can remove iron powder that may exist in flour, magnetized water can prevent boiler scaling, magnetized seeds can increase crop production.