Whole Body and Local SAR in Anatomical Phantoms Exposed to RF Fields from Birdcage Coils
نویسندگان
چکیده
A numerical study of the induced fields and specific absorption rate (SAR) in anatomical phantoms exposed to the radiofrequency (RF) fields of magnetic resonance (MR) scanners was conducted using the finite difference time domain (FDTD) method at 64MHz and 128MHz. Three phantoms including two adults and one child were used. The study revealed inconsistencies between the MRI safety standards and current scanning practices. Furthermore, the results indicate that established guidelines for demonstrating MRI safety of implants are insufficient.
منابع مشابه
SAR and B1 Field in a Human Head Model for Birdcage, TEM and Microstrip Coils at 7T
Introduction: The advantage of high field MRI is high SNR which can increase image resolution or decrease acquisition time. However, there are some challenges, such as the RF wavelength effect and the power deposition in tissues. A comparison of three different volume coils loaded with the same spherical homogeneous phantom has been reported [1]. In order to mimic the B1 field distribution and ...
متن کاملAn Assessment of the Suitability of the Body and Adult Head Coils for Transmission During Paediatric Magnetic Resonance Imaging
MRI offers physiological and diagnostic advantages over other modalities (CT, PET) and, if examining a paediatric patient, the lack of ionizing radiation is especially important. However, the process for infants is limited by the radio-frequency (RF) coils currently available which are optimized for adult anatomy. Simulation is used to confirm the safety of the coil and design performance. The ...
متن کاملExperimental estimation of local SAR in a multi-transmit system
Introduction: SAR management is a widely discussed topic at main fields of 3T or above, particularly in the framework of multi-transmit systems [1,2]. Typically, local SAR is estimated via patient model simulations, i.e., extensive numerical calculations not suitable for clinical routine. An alternative way to estimate local SAR might be given by “Electric Properties Tomography” (EPT), i.e., th...
متن کاملComparison of simulated parallel transmit body arrays at 3 T using excitation uniformity, global SAR, local SAR, and power efficiency metrics.
PURPOSE We compare the performance of eight parallel transmit (pTx) body arrays with up to 32 channels and a standard birdcage design. Excitation uniformity, local specific absorption rate (SAR), global SAR, and power metrics are analyzed in the torso at 3 T for radiofrequency (RF)-shimming and 2-spoke excitations. METHODS We used a fast cosimulation strategy for field calculation in the pres...
متن کاملNumerical simulation of SAR induced around Co-Cr-Mo hip prostheses in situ exposed to RF fields associated with 1.5 and 3 T MRI body coils.
When patients with metallic prosthetic implants undergo an MR procedure, the interaction between the RF field and the prosthetic device may lead to an increase in specific absorption rate (SAR) in tissues surrounding the prosthesis. In this work, the distribution of SAR(10g) around bilateral CoCrMo alloy hip prostheses in situ in anatomically realistic voxel models of an adult male and female d...
متن کامل