In mathematical optimization, the ordered subset expectation maximization (OSEM) method is an iterative method that is used in computed tomography.
In applications in medical imaging, the OSEM method is used for positron emission tomography, for single photon emission computed tomography, and for X-ray computed tomography.
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.
Famous quotes containing the words ordered and/or expectation:
“I am aware that I have been on many a man’s premises, and might have been legally ordered off, but I am not aware that I have been in many men’s houses.”
—Henry David Thoreau (1817–1862)
“The expectation that every neurotic phenomenon can be cured may, I suspect, be derived from the layman’s belief that the neuroses are something quite unnecessary which have no right whatever to exist. Whereas in fact they are severe, constitutionally fixed illnesses, which rarely restrict themselves to only a few attacks but persist as a rule over long periods throughout life.”
—Sigmund Freud (1856–1939)