An Improved Ordered Subsets Expectation Maximization Reconstruction

Positron emission computerized tomography (PET) based on Ordered Subsets Expectation Maximization (OS-EM) is usually used to computerized tomography, which imposes the radionuclide to emission positron. But it also has some disadvantage as costing long time and bad reconstruction quality. Filtered Back Projection (FBP) that has many advantages such as simple structure and short reconstruction time is firstly introduced to the initialization stage to fast reconstruction process. Then, the smoothness method is introduced to improve the reconstruction speed and quality after the OS-EM algorithm. The reconstructed images are compared with the standard OS-EM for both simulated phantom data and brain magnetic resonance imaging image data. The OS-EM is shown to be faster than OS-EM’s with the same iteration steps. The results also show that this method has the advantages of fast reconstruction speed and good quality.