In mathematical optimization, the ordered subset expectation maximization (OSEM) method <!-- NOT algorithm --> is an iterative method that is used in computed tomography.
In applications in medical imaging, the OSEM method is used for positron emission tomography (PET), for single-photon emission computed tomography (SPECT), and for X-ray computed tomography (X-ray CT) scans.
The OSEM method is related to the expectation–maximization (EM) method of statistics. The OSEM method is also related to methods of filtered back projection.
References
- Hudson, H.M., Larkin, R.S. (1994) "Accelerated image reconstruction using ordered subsets of projection data", IEEE Trans. Medical Imaging, 13 (4), 601–609