Atlas-based attenuation correction for PET/MRI
Positron Emission Tomography (PET) images need correction for the loss of photons. This loss, or attenuation, is due to interactions with patient tissues. Corrections are currently done with X-ray Computed Tomography (CT), however we are proposing a method whereby Magnetic Resonance Images (MRI) are used. This will be done by creating an attenuation map(?-map). The construction of ?-maps can be divided into two categories, patient specific ?-maps by MRI segmentation, and registration of a predefined atlas to an MRI. Challenges with the former include object truncation, and reliance upon heuristics to transform an MRI into a u-map. The latter technique can overcome these challenges, but relies upon the selection of an atlas that is adaptable to a patient population. We will evaluate three strategies for constructing an atlas suitable for whole-body PET/MRI. We will then compare the performance of these methods with MRI segmentation-based and the gold-standard CTbased methods.