Image Accuracy and Quality Test in Rate Constant Depending on Reconstruction Algorithms with and Without Incorporating PSF and TOF in PET Imaging

Objective: Positron emission tomography allows imaging of patho-physiological information as a form of rate constants from scanned and reconstructed dynamic image. Some reconstruction algorithms incorporated with time of flight and point spread function have been developed, and quantitative accuracy and quality in the image have been investigated. However, feasibility of the rate constants from the dynamic image has not been directly investigated. We investigated the accuracy and quality in the rate constant by scanning a phantom filled simultaneously with (11)C and (18)F.

Method: We utilized a phantom filled with (18)F-F(-) solution in the main cylinder and with (11)C-flumazenil solution in seven sub-cylinders. The phantom was scanned by a Biograph mCT and the scanned data were reconstructed with FBP- and OSEM-based algorithms incorporating with and without TOF and/or PSF corrections. Decay rate images as kinetic rate constant were computed for all the reconstructed images and quantitative accuracy and quality in the rate images were investigated.

Results: The obtained decay rates were not significantly different from the reference values for both isotopes for all applied algorithms when noise on image was not large. Respective SD was smaller in OSEM with TOF in the (11)C-filled region.

Conclusion: The present study suggests that OSEM incorporating with TOF provides reasonable quantitative accuracy and image quality regarding decay rates.