An MR compatible PET scanner based on RatCAP for small animal imaging at 9.4 T

Combining PET and MRI technology in order to obtain simultaneous functional information with anatomical precision in vivo is of tremendous interest in the field of molecular imaging. PET/MRI imaging provides perfect anatomical and temporal coregistration of PET and MR images, along with clear delineation of tissue boundaries. An MR compatible PET scanner based on Rat Conscious Animal PET (RatCAP) is developed for simultaneous acquisition of PET/MRI images of the rat brain in a 9.4 T microMRI scanner. The PET tomograph is housed in a segmented G10/copper case constructed with a copper coating thickness of 5 microns, to minimize the eddy currents and provide better RF shielding. Special RF coils were designed to fit inside the PET tomograph. A custom made G10 tube assembly was constructed for accurate positioning of the rat bed, RF coil and RatCAP. Simultaneous PET/MRI images of a rat striatum phantom were acquired in the 9.4 T microMRI with minimal interference between PET electronics and MRI. PET compatible RF quadrature coils are being constructed which are capable of providing rat brain images with improved SNR. The preliminary results show the feasibility of performing PET/fMRI studies of rat brain and exploring the possibility of acquiring simultaneous PET/MRI whole body mouse images in the 9.4 T.