Study Of Magnetic Resonance Thermometry Based On Proton Resonance Frequency

MR thermometry temperature fields, especially in the non-invasive thermalablation of tumor surgery has been widely used. By proton resonance frequencymagnetic resonance methods in temperature measurement is complete MRIthermometry cutting edge of technology. Proton resonance frequency method is basedon the achieved phenomenon of proton chemical shifts, in magnetic resonance chemicalshift is the proton resonance frequency environment because of the presence of theelectron cloud and have a certain relationship with temperature. Because of themovement and magnetic field drift effect proton resonance frequency method is difficultto achieve accurate measurement of the different resonance frequency between waterand oil, through the establishment of a new temperature model and use mathematicalalgorithms this paper obtain magnetic resonance signal frequency differenceinformation, while the selected organization the proton is insensitive to temperature asreference material, we achieve magnetic resonance thermometry functions.First establish intervals sampled temperature model, using expanded PRONYparameter estimation algorithm, through reasonable approximation to simplify thecalculation in order to increase computing speed, realized from the magnetic resonancesignal acquisition to extract the temperature-dependent frequency differenceinformation, and through calibration experiments establishing the temperature of waterand oil with the model difference between the proton resonance frequency linearity.According the needs of temperature model, design new temperature sequence andprogramming. The use of improved average algorithm obtained new sequence capturemultiple images for noise reduction, finally reconstruct temperature image.