It is a biological magnetic spin imaging technology, the “nucleus” of MRI refers to the nucleus of hydrogen atoms, because about 70% of the human body is composed of water, MRI that relies on hydrogen atoms in water. The hydrogen atoms in the human body are excited by radio frequency pulses in an applied strong magnetic field to produce nuclear magnetic resonance (NMR), and after spatial encoding technology, the NMR signal is detected and accepted in electromagnetic form by a detector and input into a computer, and after data processing and conversion, the morphology of human tissues is finally formed into images for diagnosis.