The applicants proposed to develop and optimize three dimensional (3-D) iterative reconstruction algorithms. Recently, the removal of interplane septa in multiring PET cameras has allowed oblique coincidence events to be collected and has proved to have significantly increased the sensitivity of signal detection in PET volume imaging. From the results of studies in two dimensional space, most iterative reconstructions which allow the incorporation of a model in the reconstruction algorithm can improve the image quality over the filtered backprojection reconstruction. The results of O-15 water subtraction studies, which have been shown to have increased signal-to-noise ratio (SNR) using the volume imaging technique, can be further improved by the use of 3-D iterative reconstructions.
The specific aims are: 1) To investigate the signal and noise tradeoff as a function of resolution recovery, in particular in the axial direction compared to 3-D filtered backprojection; 2) To further study the impact of a more accurate model which includes scatter, attenuation, randoms and detector homogeneity for the two iterative reconstructions on the signal and noise tradeoff. The results will be compared to 3-D filtered backprojection; and 3) To optimize the iterative 3-D reconstructions for O-15 water subtraction studies. The two iterative reconstruction algorithms interative filtered back projection (IFBP) and maximum likelihood - EM (ML-EM), will be applied to the 3-D O-15 water data sets, consisting of two groups of normal volunteers that are given a motor and speech stimulation task respectively. The improvement of SNR will be measured by change distribution analysis (CDA) over the data set and compared with the results from filtered backprojection. Efforts will also be made to optimize the reconstruction code over four CSPI supercard II array processors to reduce the reconstruction time for clinical studies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29NS033721-04
Application #
2655499
Study Section
Special Emphasis Panel (ZRG7-SSS-X (33))
Program Officer
Jacobs, Tom P
Project Start
1995-02-01
Project End
2000-01-31
Budget Start
1998-02-01
Budget End
1999-01-31
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
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Liow, J S; Strother, S C; Rehm, K et al. (1997) Improved resolution for PET volume imaging through three-dimensional iterative reconstruction. J Nucl Med 38:1623-31