Iterative image reconstruction for clinical PET using ordered subsets, median root prior, and a web-based interface

Kontaxakis, G; Strauss, LG; Thireou, T; Ledesma-Carbayo, MJ; Santos, A; Pavlopoulos, SA; Dimitrakopoulou-Strauss, A

dc.contributor.author	Kontaxakis, G	en
dc.contributor.author	Strauss, LG	en
dc.contributor.author	Thireou, T	en
dc.contributor.author	Ledesma-Carbayo, MJ	en
dc.contributor.author	Santos, A	en
dc.contributor.author	Pavlopoulos, SA	en
dc.contributor.author	Dimitrakopoulou-Strauss, A	en
dc.date.accessioned	2014-03-01T01:18:00Z
dc.date.available	2014-03-01T01:18:00Z
dc.date.issued	2002	en
dc.identifier.issn	15361632	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14751
dc.subject	Attenuation correction factors	en
dc.subject	Distributed pentium systems	en
dc.subject	Iterative image reconstruction	en
dc.subject	Maximum likelihood expectation maximization	en
dc.subject	Median root prior	en
dc.subject	Ordered subsets	en
dc.subject	Web-based interface	en
dc.subject.other	algorithm	en
dc.subject.other	article	en
dc.subject.other	artifact reduction	en
dc.subject.other	Bayes theorem	en
dc.subject.other	brain	en
dc.subject.other	calculation	en
dc.subject.other	computer interface	en
dc.subject.other	computer program	en
dc.subject.other	computer simulation	en
dc.subject.other	computer system	en
dc.subject.other	controlled study	en
dc.subject.other	image processing	en
dc.subject.other	image quality	en
dc.subject.other	image reconstruction	en
dc.subject.other	Internet	en
dc.subject.other	positron emission tomography	en
dc.subject.other	priority journal	en
dc.subject.other	technique	en
dc.subject.other	time	en
dc.subject.other	validation process	en
dc.subject.other	Salvia	en
dc.title	Iterative image reconstruction for clinical PET using ordered subsets, median root prior, and a web-based interface	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S1536-1632(02)00004-5	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S1536-1632(02)00004-5	en
heal.publicationDate	2002	en
heal.abstract	Purpose: The development, implementation and validation of simple, flexible and efficient iterative image reconstruction (IIR) methods for their take-up in routine clinical positron emission tomography (PET) static or dynamic studies. Procedures: The ordered subsets (OS) technique applied for the acceleration of the maximum likelihood expectation maximization (MLEM) IIR algorithm is here extended to include the weighted least-squares (WLS), image space reconstruction algorithm (ISRA) and the space alternating generalized EM (SAGE). The median root prior (MRP) has been successfully applied as a Bayesian regularization to control the noise level in the reconstructed images. All methods are implemented on distributed Pentium systems and tested using simulated PET data from a brain phantom. A Javascript is used for the initiation of the reconstruction. Results: Taking into consideration the image quality and the time required for the reconstruction, the MRP-OSEM (ordered subsets expectation maximization) seems to provide best results after four to eight iterations, with four subsets and a MRP coefficient of 0.2-0.4. Iterative reconstruction of the transmission images with OS-acceleration and MRP regularization with subsequent calculation of the attenuation correction factors (ACFs) is shown to effectively remove streak artifacts in the emission images, especially along paths of high attenuation. Conclusions: An efficient implementation using distributed processing principles and a web-based interface allows the reconstruction of one frame (with 63 cross-section slices) from a dynamic determination in few minutes. This work showed that regular PC systems can provide fast execution and produce results in clinically meaningful times. This eradicates the argument of the computational burden of the method that prevented the extensive use of IIR in today's modern PET systems. © 2002 Elsevier Science, Inc. All rights reserved.	en
heal.journalName	Molecular Imaging and Biology	en
dc.identifier.doi	10.1016/S1536-1632(02)00004-5	en
dc.identifier.volume	4	en
dc.identifier.issue	3	en
dc.identifier.spage	219	en
dc.identifier.epage	231	en