RF System The Most Basic Part
RF system is the most basic part of the magnetic resonance equipment, including the transmission and reception of two parts, because the part of the circuit components, RF System high power contacts, and frequent switching, contact easy to damage, the probability of failure is relatively large. When the RF system in any part of the problem, will make the whole device completely paralyzed, RF System even the most basic and simple task can not be completed. Therefore, it is of great practical significance to analyze and summarize the troubleshooting of this problem and improve the ability of troubleshooting.
The main task of the magnetic resonance RF system is to generate the RF pulse for the excitation of the spin, while receiving the excitation of the spin of the RF signal that the MR signal, its amplification and then digital and further processing. The following to our hospital Elscint / GEPrestige
2T magnetic resonance, for example, shows the composition of the RF system. MRI equipment RF system by the electronic control cabinet in the launch and receive unit, radio frequency amplifier, RF coil and RF switch boxes and other components.
The transmitter and receiver unit includes the transmitter and receiver interface board SBIF, the synthesis board Syn2thesizer, RF System the transmitter board XMTR and the four receiver boards RCVR. The SBIF board not only serves as the interface between the host and transmitter and receiver units, but also generates a 2.5MHz transmitter amplitude modulation signal. A transmitting board SMV generates an RF signal as an input signal of a radio frequency amplifier according to a specific situation of the scanning task and the imaging human body to be completed; and the receiving plate RCVR converts the obtained high frequency magnetic resonance Signal into low-frequency signal, and then converted into digital signal by analog to digital.
The RF amplifier amplifies the small RF signal provided by the transmitting unit to produce a powerful RF pulse that stimulates the imaging organization via the head coil, RF System the body coil, and the knee coil. The RF amplifiers use the ETO 20kW automatic RF amplifier, which produces a 73dB gain at a center frequency of 81.27MHz, which drives a two-stage gate-to-ground vacuum tube amplifier through a three-stage solid-state driver.
RF coil has two basic functions of transmitting and receiving, in addition to the first coil, body coil and knee three active coil, but also equipped with a head and neck joint coil, lumbar coil, pelvic coil, phased array coil passive coil, passive coil Is driven by the body coil.