Title :
Tailoring magnetic field gradient design to magnet cryostat geometry
Author :
Trakic, A. ; Liu, Frank ; Lopez, Hector Sanchez ; Wang, Huifang ; Crozier, Stuart
Author_Institution :
Queensland Univ., Qld.
Abstract :
Eddy currents induced within a magnetic resonance imaging (MRI) cryostat bore during pulsing of gradient coils can be applied constructively together with the gradient currents that generate them, to obtain good quality gradient uniformities within a specified imaging volume over time. This can be achieved by simultaneously optimizing the spatial distribution and temporal pre-emphasis of the gradient coil current, to account for the spatial and temporal variation of the secondary magnetic fields due to the induced eddy currents. This method allows the tailored design of gradient coil/magnet configurations and consequent engineering trade-offs. To compute the transient eddy currents within a realistic cryostat vessel, a low-frequency finite-difference time-domain (FDTD) method using total-field scattered-field (TFSF) scheme has been performed and validated
Keywords :
biomedical MRI; biomedical equipment; coils; cryostats; eddy currents; finite difference time-domain analysis; FDTD; gradient coil current; low-frequency finite-difference time-domain method; magnet cryostat geometry; magnetic field gradient design; magnetic resonance imaging; secondary magnetic field; spatial distribution; temporal distribution; total-field scattered-field scheme; transient eddy currents; Boring; Coils; Design engineering; Eddy currents; Finite difference methods; Geometry; Magnetic fields; Magnetic resonance imaging; Magnetosphere; Time domain analysis;
Conference_Titel :
Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE
Print_ISBN :
1-4244-0032-5
Electronic_ISBN :
1557-170X
DOI :
10.1109/IEMBS.2006.259223