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| Content Provider | IEEE Xplore Digital Library |
|---|---|
| Author | King, M.A. deVries, D.J. Pan, T.-S. Pretorious, P.H. Case, J.A. |
| Copyright Year | 1997 |
| Description | Author affiliation: Dept. of Nucl. Med., Massachusetts Univ. Med. Center, Worcester, MA, USA (King, M.A.) |
| Abstract | With the Triple Energy Window (TEW) scatter correction method, scatter is estimated by interpolation between narrow energy windows placed on either side (or from a single window just below) the photopeak window. The use of narrow windows results in a noisy estimate which requires filtering to prevent significant amplification of noise in the corrected images. Using Monte Carlo simulated projections of a digital model of the anatomy of the torso, we investigated two-dimensional pre-reconstruction filtering of the scatter estimate by the Wiener low-pass filter, and Butterworth low-pass filters with various cutoff frequencies. The scatter estimate was either subtracted from the photopeak window projection or used directly in ordered-subset maximum-likelihood (OS-ML) reconstruction. Using the normalized mean square error (NMSE) between the estimated and true slices as the criterion, it was observed that: (1) low-pass filtering of the TEW scatter estimate dramatically decreases the NMSE compared to that of no filtering of this estimate; (2) the cutoff frequency of the Butterworth filter used to filter the scatter estimate is lower than that typically used for photopeak window images; (3) the cutoff frequency of the Butterworth filter has a broad range of values over which the NMSE is near its minimum value; (4) the cutoff frequency at which the Butterworth reaches its minimum value depends on the number of counts in the TEW window(s), and source distribution; (5) the Wiener low-pass filter adapts to produce a low, but not necessarily the minimum, NMSE; and (6) the inclusion of the scatter estimate directly into OS-ML reconstruction results in a lower NMSE than subtraction of the scatter estimate from the photopeak window prior to reconstruction. |
| Starting Page | 1077 |
| Ending Page | 1081 |
| File Size | 677715 |
| Page Count | 5 |
| File Format | |
| ISBN | 0780335341 |
| ISSN | 10823654 |
| DOI | 10.1109/NSSMIC.1996.591556 |
| Language | English |
| Publisher | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Publisher Date | 1996-11-02 |
| Publisher Place | USA |
| Access Restriction | Subscribed |
| Rights Holder | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Subject Keyword | Filtering Scattering Low pass filters Frequency estimation Cutoff frequency Digital filters Image reconstruction Wiener filter Interpolation Monte Carlo methods |
| Content Type | Text |
| Resource Type | Article |
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