PET Myocardial Perfusion Imaging of Extremely Obese Patients: A Study with an Ultra-Large Anthropomorphic Cardiac-Torso Phantom

An increasing number of extremely obese patients (BMI > 40 kg/m
²
) undergo PET myocardial perfusion imaging (MPI), posing great demands for accurate activity quantitation. An ultra-large anthropomorphic cardiac-torso phantom was custom built to study this case. The phantom was loaded with F-18 with organ concentrations modeling a Rb-82 MPI study. Transmural and 50% transmural defects were placed in the cardiac insert. The phantom was imaged on a TOF PET/CT scanner using clinical acquisition and image reconstruction protocols. Some truncation and streak artifacts were observed on the x-ray CT scan used for attenuation and scatter correction. Myocardial activity appeared relatively uniform and the defects were easily seen in short axis heart slices. Cardiac segments not containing defects showed good uniformity and had normalized perfusion values > 85% of the peak segmental value. An ultra-large anthropomorphic torso phantom is valuable to model Rb-82 myocardial perfusion studies of extremely obese patients.