Motion compensation in histogram-mode and list-mode EM reconstructions: Beyond the event-driven approach
Motion compensation in histogram-mode and list-mode EM reconstructions: Beyond the event-driven approach
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DOI：
10.1109/tns.2004.835763
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发表时间：
2004-10-01
影响因子：
1.8
通讯作者：
Sossi, V
中科院分区：
文献类型：
--
作者：
Rahmim, A;Bloomfield, P;Sossi, V
With continuous improvements in spatial resolution of positron emission tomography (PET) scanners, small patient movements during PET imaging become a significant source of resolution degradation. This work explores incorporation of motion information into expectation-maximization (EM) reconstruction algorithms. An important issue addressed is the existence of lines-of-response (LORs) corresponding to no actual pairs of detectors and their motion-induced "interaction" with the detectable LORs. An example of this is a scanner design with gaps existing in between the detector heads. It is shown that to properly account for such LORs in histogram-mode and list-mode EM reconstructions, in addition to motion correction of the events, the algorithms themselves must be modified. This modification is implemented by including motion-compensated sensitivity correction factors. We are able to demonstrate experimentally that the proposed approach resolves image artifacts that can appear when the conventional purely event-driven motion correction technique is used. An alternate image-space-based method for calculation of motion-compensated sensitivity factors is also derived, applicable in both histogram-mode and list-mode reconstruction tasks, which has the potential of being considerably faster in presence of frequent motion, especially in high-resolution tomographs.
