HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Liow, J.-S. Articles by Rottenberg, D. A. Search for Related Content PubMed PubMed Citation Articles by Liow, J.-S. Articles by Rottenberg, D. A.

Improved Resolution for PET Volume Imaging through Three-Dimensional Iterative Reconstruction

PET imaging, Veterans Administration Medical Center
Departments of Radiology and Neurology, University of Minnesota, Minneapolis, Minnesota

Correspondence: For correspondence or reprints contact: Jeih-San Liow, PhD, PET Imaging (11P), VA Medical Center, One Veterans Dr., Minneapolis, MN 55147.

ABSTRACT

It has been demonstrated that in two-dimensional iterative reconstruction, a resolution model can improve image resolution while controlling noise. With the lower noise levels of three-dimensional PET volume imaging, these iterative reconstruction advantages may be extended to three dimensions to further improve the reconstructed image resolution. Methods: We have implemented three-dimensional versions of iterative filtered backprojection (IFBP) and the maximum likelihood by expectation maximization (ML-EM) reconstruction algorithms and applied them to three-dimensional PET volume dataseis. The results were compared to images obtained using the standard three-dimensional reprojection reconstruction (3DRP) algorithm. Results: For IFBP with 15 iterations and no regularizaron compared to 3DRP, both using a ramp filter, the transaxial resolution improved 52%, and the axial resolution improved 39%. With a strong regularization, the transaxial and axial resolution improvements were reduced to 6% and 5%, respectively. If a Hanning roll-off is applied to the ramp filter in the transaxial direction, the transaxial resolution for IFBP without regularization improved 35% compared to 3DRP; with regularization the improvement dropped to 19%. The axial resolution for IFBP and 3DRP was unaffected by this transaxial smoothing in the reconstruction filter. With the same Hanning roll-off, the noise for IFBP without regularization increased by a factor of 6 compared to 3DRP; with regularization the noise was increased only by a factor of 3. Compared to IFBP, the three-dimensional ML-EM reconstruction produced lar resolution improvements with a much smaller increase in noise and slower convergence. Resolution improvements from both IFBP and ML-EM reconstructions are visually apparent in three-dimensional FDG brain images and result in increased activation signals in a three-dimensional [¹⁵O]water functional activation study. Conclusion: Our results demonstrate that resolution improvement is possible for IFBP and ML-EM compared to 3DRP with or without noise increase.

Key Words: PET • three-dimensional volume imaging • iterative reconstruction • resolution improvement

This article has been cited by other articles:

				G. Tarantola, F. Zito, and P. Gerundini PET Instrumentation and Reconstruction Algorithms in Whole-Body Applications J. Nucl. Med., May 1, 2003; 44(5): 756 - 769. [Abstract] [Full Text] [PDF]

				R. Boellaard, A. van Lingen, and A. A. Lammertsma Experimental and Clinical Evaluation of Iterative Reconstruction (OSEM) in Dynamic PET: Quantitative Characteristics and Effects on Kinetic Modeling J. Nucl. Med., May 1, 2001; 42(5): 808 - 817. [Abstract] [Full Text]