The Design For Radio Frequency(RF) Coil Of MRI Based On Low Field Condition

Magnetic resonance imaging(MRI)has become an important tool in medical imaging because of its non-ionizing,no radioactive and non-invasive advantages.The conventional designs in the light of 1H nuclear magnetic resonance equipment mostly.However,this kind if equipment is unable to effectively imaging the lungs for the most crucial three reasons:1.Lung is lack of water.2.The density of lung is extremely low.3.The permeability of lung is not homogeneity.The polarization gas is very significant for the research of MRI in the lung.The radio frequency(RF)coil is an important component in magnetic resonance devices,which can be used to stimulate the nucleus and receive magnetic resonance signals.The superiority of the RF coil determines the quality of the imaging.In this paper,three sets of RF coils and multi-frequency point coil systems with low field(600Gs)are designed based on ultra-polarized gas 3He,and experimental verification is carried out.The main work of this paper is as follows:First,the basic principle of magnetic resonance imaging,the basic structure of magnetic resonance equipment and the basic principle of ultra-polarized gas are introduced.Then the basic principle of RF coil,the parameters of RF coil and the design principle of the common RF coil are introduced.It also introduces the circuit of RF coil,including tuning of coil,matching of coil and decoupling of coil.Secondly,solenoid RF coils of based on 1H nucleus and 3He atoms are designed under the 600Gs.In this paper,a MRI experiment was performed for the rat,and the feasibility of the ultra-polarized gas 3He magnetic resonance imaging was verified based on 600Gs.In addition,for 3He imaging,the butterfly transmission coil and the four-channel surface array receiver coil are designedbased on 600Gs.The coil was experimentally tested with the vector network analyzer and the reflection parameters(S11)and the coupling parameters(S12)were obtained.Finally,we designed a multi-frequency point RF coil systembased on 600Gs,and thereare two frequency points set by multi-frequency point RF coil system are 2.68MHz(1H)and 1.94MHz(3He).