Comparative evaluation of two commercial PET scanners, ECAT EXACT HR+ and Biograph 2, using GATE Journal Article


Authors: Karakatsanis, N.; Sakellios, N.; Tsantilas, N. X.; Dikaios, N.; Tsoumpas, C.; Lazaro, D.; Loudos, G.; Schmidtlein, C. R.; Louizi, K.; Valais, J.; Nikolopoulos, D.; Malamitsi, J.; Kandarakis, J.; Nikita, K.
Article Title: Comparative evaluation of two commercial PET scanners, ECAT EXACT HR+ and Biograph 2, using GATE
Abstract: Geant4 application for tomographic emission (GATE) is a generic Monte Carlo simulation platform based on a general-purpose code GEANT4 and designed to simulate positron emission tomography (PET) and single photon emission tomography systems. Monte Carlo simulations are used in nuclear medicine to model imaging systems and develop and assess tomographic reconstruction algorithms and correction methods for improved image quantification. The purpose of this study is to validate two GATE models of the commercial available PET scanner HR+ and the PET/CT Biograph 2. The geometry of the system components has been described in GATE, including detector ring, crystal blocks, PMTs etc. The energy and spatial resolution of the scanners as given by the manufacturers have been taken into account. The GATE simulated results are compared directly to experimental data obtained using a number of NEMA NU-2-2001 performance protocols, including spatial resolution, sensitivity and scatter fraction. All the respective phantoms are precisely modeled. Furthermore, an approximate dead-time model both at the level of single and coincidence events was developed so that the simulated count rate curve can satisfactorily match the experimental count rate performance curve for each scanner In addition a software tool was developed to build the sinograms from the simulated data and import them into the software for tomographic image reconstruction where the reconstruction algorithm of FBP3DRP was applied. An agreement of less than 0.8 mm was obtained between the spatial resolution of the simulated system and the experimental results. Also the simulated scatter fraction for the NEMA NU 2-2001 scatter phantom matched the experimental results to within 3% of measured values. Finally the ratio of the simulated sensitivities with sources radially offset 0 and 10 cm from the central axis of each of the two scanners reaches an agreement of less than 1% between the simulated and experimental values. This simulation code will be used in a second phase in order to study scatter phenomena and motion artifacts. The simulation results will be used to optimize image reconstruction algorithms, with emphasis on dynamic PET studies. © 2006.
Keywords: positron emission tomography; computerized tomography; computer simulation; pet; validation; image reconstruction; gate; monte carlo simulations; monte carlo methods; data acquisition; biograph; hr+; biographs; geant4 application for tomographic emission (gate); single photon emission tomography systems
Journal Title: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume: 569
Issue: 2 Suppl.
ISSN: 0168-9002
Publisher: Elsevier Science BV  
Date Published: 2006-12-20
Start Page: 368
End Page: 372
Language: English
DOI: 10.1016/j.nima.2006.08.110
PROVIDER: scopus
DOI/URL:
Notes: Presented at the 3rd International Conference on Imaging Technologies in Biomedical Sciences, Innovation in Nuclear and Radiological Imaging: From Basic Research to Clinical Application; 2005 Sep 25-29; Milos Island, Greece -- "Cited By (since 1996): 13" -- "Export Date: 4 June 2012" -- "CODEN: NIMAE" -- "Source: Scopus"
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