Md Shahadat Hossain Akram1, Craig S. Levin2, Takayuki Obata1, Fumihiko Nishikido1, Eiji Yoshida1, and Taiga Yamaya1
1Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan, 2School of Medicine, Stanford University, Stanford, CA, United States
A prototype of a novel oval shape PET insert for
simultaneous body imaging with the MRI systems has been proposed in this study.
The smaller prototype has the minor axis and major axis of 14 cm and 21 cm. 16
copper shielded boxes are positioned on the periphery of the oval frame. The
shielding boxes were kept floating to let the RF field penetrate through the
gaps in between the 16 modules. To get the required RF field distribution
inside the oval PET, the gaps between the shielded modules were varied by doing
assumptions following the conformal electric phase angle methods. B1 maps and GRE and SE images were
taken and they have a good agreement with the results for without shielding
materials. We have found a reduced RF field value with increased noise in the
FOV which is mostly due to shielding materials. The images of GRE and SE have shape
distortions due eddy currents.