Abstract:
:Statistically based iterative image reconstruction methods have been developed for emission tomography. One important component in iterative image reconstruction is the system matrix, which defines the mapping from the image space to the data space. Several groups have demonstrated that an accurate system matrix can improve image quality in both single photon emission computed tomography (SPECT) and positron emission tomography (PET). While iterative methods are amenable to arbitrary and complicated system models, the true system response is never known exactly. In practice, one also has to sacrifice the accuracy of the system model because of limited computing and imaging resources. This paper analyses the effect of errors in the system matrix on iterative image reconstruction methods that are based on the maximum a posteriori principle. We derived an analytical expression for calculating artefacts in a reconstructed image that are caused by errors in the system matrix using the first-order Taylor series approximation. The theoretical expression is used to determine the required minimum accuracy of the system matrix in emission tomography. Computer simulations show that the theoretical results work reasonably well in low-noise situations.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Qi J,Huesman RHdoi
10.1088/0031-9155/50/14/007subject
Has Abstractpub_date
2005-07-21 00:00:00pages
3297-312issue
14eissn
0031-9155issn
1361-6560pii
S0031-9155(05)89047-5journal_volume
50pub_type
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