Consistency driven respiratory phase alignment and motion compensation in PET/CT

Respiratory motion in PET/CT imaging degrades PET image quantitation due to misaligned attenuation correction (AC) factors and motion blurring. This work explores the use of the Radon consistency conditions to compensate for these limitations in respiratory gated PET images in which only a single CT scan is available for AC. Specifically, we use the Radon consistency of AC-PET data as a metric to transform the attenuation map to match each phase of respiratory gated data, perform phase matched AC, and then use the inverse of the transformation parameters to align the gated PET images into a single phase. A final image volume is formed from summing PET images aligned to a single phase. We test this method with three transformation types applied to simulated data and measured patient PET/CT data. Results show successful alignment of attenuation maps and minor quantitative improvement with the proposed methods.