Positron range and acollinearity modeling for hybrid PET/CT and PET/MR imaging

The development of integrated devices to combine Positron Emission Tomography (PET) and Magnetic Resonance (MR) imaging has been a constant trend in multimodal imaging for the last years. However, a number of approaches have shown that positron range and the acollinearity are fundamental limitations of PET image resolution. According to these studies, its effect is especially relevant with some radionuclides currently used in clinical and preclinical studies such as 82Rb, 124I and 68Ga. The aim of this project is threefold: 1 – Modeling the positron range and acollinearity of clinically relevant PET isotopes for different tissue types with and without the presence of a magnetic field. 2 – Validation of the positron model using phantom measurements with different isotopes and (pre)clinical PET/MRI and PET/CT systems. 3 – Use of the attenuation map derived from CT, MRI or PET only data to account for tissue dependent positron range during reconstruction.