Methods to reconstruct emission and transmission data in 3D PET

Methods of reconstruction and quantitation are developed for a 3D system and are evaluated on the HEAD PENN-PET scanner, which has a very large axial acceptance angle (+/-28 degrees in the center) and large axial field-of-view without septa (25.6 cm). To overcome the difficulties of data storage and reconstruction time with 3D reconstruction, we have reduced the size of the 4-D projection matrix required for 3D-RP reconstruction, and compared the results to the Fourier rebinning (FORE) algorithm. Both approaches achieve a favorable tradeoff in data storage requirements, reconstruction time, and accuracy that are suitable for clinical use. We have also studied the application of the FORE algorithm to transmission scans acquired with a singles point source (Cs-137) so that data quantitation can be performed.