A source and object dependent scatter correction method for transmission and emission imaging

The scattered background in PET imaging has a complex dependency on the source distribution and attenuation object composition and shape, as well as detector characteristics such as energy resolution and aperture size. Software-based scatter correction techniques must make simplifying assumptions about these dependencies. The authors have developed an analytical method for calculating the single scatter component in both emission and transmission imaging. This method includes the relevant detector characteristics and Klein-Nishina scattering physics, but takes no account of any fraction of the source or attenuating object which lies outside of the field of view. Monte Carlo simulations which included multiple scattering were used to evaluate the accuracy of this analytical scatter calculation. The correction method was then applied to measured emission and transmission data, obtained from a phantom experiment with the authors´ QPET system, to demonstrate its effectiveness. An uncollimated flood source was used to perform the transmission scan