Evaluation of MR-based PET Images with a Homogeneous μmap by Using Integrated PET/MR

This study intends to obtain magnetic resonance (MR)-based positron emission tomography (PET) images with a relatively uniform μmap by using a National Electrical Manufacturers Association (NEMA) International Electrotechnical Commission (IEC) body phantom and to evaluate the PET phantom images by applying various reconstruction parameters in accordance with the protocol of the NEMA. In order to obtain a uniform MR-based μmap, we set the initial voltage of the RF transmitter adjustment algorithm to 75 V, and we obtained the attenuation-corrected PET image by applying the two-point vibe Dixon MR sequence. The images reconstructed using the 3D ordered subset expectation maximization (OSEM) algorithm with the point spread function (PSF) showed the highest percentage of contrast recovery and the lowest percentage background variability compared to the other 3D reconstruction algorithms like the Filtered backprojection (FBP), 3D OSEM, and 3D OSEM with PSF algorithms. The 3D OSEM with PSF reconstruction algorithm is confirmed to be effective for maintaining the optimum image quality.