Radiofrequency power deposition utilizing thermal imaging
Radiofrequency power deposition utilizing thermal imaging
复制标题
DOI：
10.1002/mrm.20064
复制
发表时间：
2004-06-01
影响因子：
3.3
通讯作者：
Barber, W
中科院分区：
文献类型：
--
作者：
Cline, H;Mallozzi, R;Barber, W
波长效应影响射频（RF）功率沉积分布，并限制磁共振（MR）在非常高的磁场中的医疗应用。从质子共振位移热图推导出在1.5 T和3.0 T的电导率范围内的球形盐凝胶幻影的功率沉积。测量了正交头部线圈和圆形表面线圈射频加热前后的相位差。具有3D相位展开算法的长回波时间（TE）脉冲序列提供了增加的热灵敏度。测得的热图同意的涡流加热模型的圆极化振荡RF场在导电介质球。在3.0 T时，使用
Wavelength effects influence radiofrequency (RF) power deposition distributions and limit magnetic resonance (MR) medical applications at very high magnetic fields. The power depositions in spherical saline gel phantoms were deduced from proton resonance shift thermal maps at both 1.5 T and 3.0 T over a range of conductivities. Phase differences before and after RF heating were measured for both a quadrature head coil and a circular surface coil. A long echo time (TE) pulse sequence with a 3D phase unwrap algorithm provided increased thermal sensitivity. The measured thermal maps agreed with a model of eddy-current heating by circularly polarized oscillating RF fields in a conducting dielectric sphere. At 3.0 T, thermal maps were acquired with a