Editing Ordered subset expectation maximization

{{about|an algorithm|Israeli food corporation|Osem (company)}}
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 [[computed tomography|X-ray computed tomography]] (X-ray CT) scans.

The OSEM method is related to the [[expectation–maximization algorithm|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&ndash;609 {{doi|10.1109/42.363108}}

[[Category:Optimization algorithms and methods]]
[[Category:Medical statistics]]
[[Category:Medical imaging]]


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