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dc.contributor.authorUche, Chibueze Zimuzo
dc.contributor.authorCree, Michael J.
dc.contributor.authorRound, W. Howell
dc.identifier.citationUche, C.Z., Cree, M.J. & Round, W.H. (2011). GEANT4 simulation of the effects of Doppler energy broadening in Compton imaging. Australasian Physical & Engineering Science in Medicine, 10 May 2011.en_NZ
dc.description.abstractA Monte Carlo approach was used to study the effects of Doppler energy broadening on Compton camera performance. The GEANT4 simulation toolkit was used to model the radiation transport and interactions with matter in a simulated Compton camera. The low energy electromagnetic physics model of GEANT4 incorporating Doppler broadening developed by Longo et al. was used in the simulations. The camera had a 9 × 9 cm scatterer and a 10 × 10 cm absorber with a scatterer to-absorber separation of 5 cm. Modelling was done such that only the effects of Doppler broadening were taken into consideration and effects of scatterer and absorber thickness and pixelation were not taken into account, thus a ‘perfect’ Compton camera was assumed. Scatterer materials were either silicon or germanium and the absorber material was cadmium zinc telluride. Simulations were done for point sources 10 cm in front of the scatterer. The results of the simulations validated the use of the low energy model of GEANT4. As expected, Doppler broadening was found to degrade the Compton camera imaging resolution. For a 140.5 keV source the resulting full-width-at-half-maximum (FWHM) of the point source image without accounting for Doppler broadening and using a silicon scatterer was 0.58 mm. This degraded to 7.1 mm when Doppler broadening was introduced and degraded further to 12.3 mm when a germanium scatterer was used instead of silicon. But for a 511 keV source, the FWHM was better than for a 140 keV source. The FWHM improved to 2.4 mm for a silicon scatterer and 4.6 mm for a germanium scatterer. Our result for silicon at 140.5 keV is in very good agreement with that published by An et al.en_NZ
dc.subjectDoppler broadeningen_NZ
dc.subjectCompton cameraen_NZ
dc.subjectCompton scatteringen_NZ
dc.subjectGamma raysen_NZ
dc.titleGEANT4 simulation of the effects of Doppler energy broadening in Compton imagingen_NZ
dc.typeJournal Articleen_NZ
dc.relation.isPartOfAustralasian Physical & Engineering Science in Medicineen_NZ

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