Electronic Thesis and Dissertation Repository


Master of Science


Medical Biophysics


Dr. Robert Stodlika


Attenuation correction (AC) in PET/MRI is difficult as there is no clear relationship between MR signal and 511 keV attenuation coefficients (μ). One strategy is to align a pre-defined atlas of μ to the PET/MRI for AC. However, atlas design may influence quantitative accuracy of AC. In this thesis we compare 3 atlas design strategies and evaluate their performance in an oncology patient population. The 3 strategies were: correction with BMI-dependent atlases; gender-dependent atlases, and a gender- and sex-independent atlas. Patients were imaged with FDG PET/CT and 3T MRI. The atlases were created and then used for PET AC of patients not included in the atlas construction. Resulting PET images were compared to CT-based PET reconstructions across all voxels and tissue-specific volumes. For the purposes of AC, there is value in developing specialized atlases. To this end, gender plays a more important role than body mass index in atlas construction.