Gene/Protein
Disease
Symptom
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Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.4.11.18 (
MAP
)
7,412
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Statistical reconstruction has become popular in emission computed tomography but suffers slow convergence (to the
MAP
or ML solution). Methods proposed to address this problem include the fast but non-convergent OSEM and the convergent RAMLA [1] for the ML case, and the convergent BSREM [2], relaxed OS-
SPS
and modified BSREM [3] for the
MAP
case. The convergent algorithms required a user-determined relaxation schedule. We proposed fast convergent OS reconstruction algorithms for both ML and
MAP
cases, called COSEM (Complete-data OSEM), which avoid the use of a relaxation schedule while maintaining convergence. COSEM is a form of incremental EM algorithm. Here, we provide a derivation of our COSEM algorithms and demonstrate COSEM using simulations. At early iterations, COSEM-ML is typically slower than RAMLA, and COSEM-
MAP
is typically slower than optimized BSREM while remaining much faster than conventional
MAP
-EM. We discuss how COSEM may be modified to overcome these limitations.
...
PMID:An overview of fast convergent ordered-subsets reconstruction methods for emission tomography based on the incremental EM algorithm. 1809 46
