Lesion quantification in oncological positron emission tomography: A maximum likelihood partial volume correction strategy

Elisabetta De Bernardi, Elena Faggiano, Felicia Zito, Paolo Gerundini, Giuseppe Baselli

Research output: Contribution to journalArticlepeer-review

Abstract

A maximum likelihood (ML) partial volume effect correction (PVEC) strategy for the quantification of uptake and volume of oncological lesions in F 18 -FDG positron emission tomography is proposed. The algorithm is based on the application of ML reconstruction on volumetric regional basis functions initially defined on a smooth standard clinical image and iteratively updated in terms of their activity and volume. The volume of interest (VOI) containing a previously detected region is segmented by a k -means algorithm in three regions: A central region surrounded by a partial volume region and a spill-out region. All volume outside the VOI (background with all other structures) is handled as a unique basis function and therefore "frozen" in the reconstruction process except for a gain coefficient. The coefficients of the regional basis functions are iteratively estimated with an attenuation-weighted ordered subset expectation maximization (AWOSEM) algorithm in which a 3D, anisotropic, space variant model of point spread function (PSF) is included for resolution recovery. The reconstruction-segmentation process is iterated until convergence; at each iteration, segmentation is performed on the reconstructed image blurred by the system PSF in order to update the partial volume and spill-out regions. The developed PVEC strategy was tested on sphere phantom studies with activity contrasts of 7.5 and 4 and compared to a conventional recovery coefficient method. Improved volume and activity estimates were obtained with low computational costs, thanks to blur recovery and to a better local approximation to ML convergence.

Original languageEnglish
Pages (from-to)3040-3049
Number of pages10
JournalMedical Physics
Volume36
Issue number7
DOIs
Publication statusPublished - 2009

Keywords

  • Maximum likelihood reconstruction
  • Partial volume effect correction
  • PET
  • Regional basis functions
  • Uptake quantification
  • Volume estimate

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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