Attenuation correction for MR table and coils for a sequential PET/MR system

Abstract

A sequential PET/MR system like Philips Gemini TF PET/MR system generates attenuation correction map from an MR image instead of a CT or transmission image for PET reconstruction. One problem in MR-based attenuation correction is that the MR table and coils are invisible in MR images but they may contain high density materials which have to be compensated for attenuation. This work investigates the attenuation impacts of the Gemini TF PET/MR table and several clinical MR coils to MR-based PET attenuation correction. To compensated the impacts of the MR tables and coils, a template inserting based approach is proposed. Templates of the MR table and coils are generated from transmission scans of the table and coils, which are pre-install on the PET/MR system. For each PET/MR scan, templates are inserted into the attenuation map generated from the MR image at the corresponding location before PET image reconstruction. Phantom studies have shown that with this template based attenuation correction approach, the PET/MR table and coils can be properly compensated for PET attenuation.