Study on the radiofrequency transparency of partial-ring oval-shaped prototype PET inserts in a 3  T clinical MRI system

In this study, we used electrically floating Faraday RF shield cages to construct different partial-ring configurations of oval and cylindrical PET inserts and performed experiments on the RF field, spin echo and gradient echo images for a homogeneous phantom in a 3  T clinical MRI system. For each geometry, partial-ring configurations were studied by removing an opposing pair or a single shield cage from different positions of the PET ring. Compared to the MRI-only case, reduction in mean RF homogeneity, flip angle, and SNR for the detector opening in the fir st and third quadrants was approximately 13%, 15%, and 43%, respectively, whereas the values were 8%, 23%, and 48%, respectively, for the detector openings in the second and fourth quadrants. The RF field distribution also varied for different partial-ring configurations. It can be concluded that th e field penetration was high for the detector openings in the first and third quadrants of both the inserts.

Source: Radiological Physics and Technology - October 24, 2023 Category: Physics Source Type: research