Feasibility of PET Attenuation Characterization of MR Hardware Using 3D Data from a LINAC as Radiation Source

Stephan Biber¹, Ralf Ladebeck¹, David Faul², Yvonne Candidus¹

With the introduction of integrated MR-PET systems both for preclinical animal studies as well as full sized human scanners, the question of PET attenuation originating from MR hardware (MR-HW) which is located between the patient and the PET camera, has been a topic of increasing interest for research. Prvious studies have identified mechanical structures for the patient table, the housings of local coils as well as the electronics and antenna structures within these housings as the major contributions to PET signal attenuation. This attenuation map needs to be included in the PET reconstruction. The goal of this paper is to evaluate the feasibility and the potential advantages of MR-HW attenuation correction based on 3D data coming from a LINAC instead of a CT, which has been used for measurement of hardware attenuation in earlier studies. The advantage of a LINAC based scan can be the reduced level of artifacts, as the LINAC provides a radiation beam with photons of much higher energy than the CT.