Title:
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Modelling of high-energy contamination in SPECT imaging using Monte Carlo simulation
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Author:
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Cot Sanz, Alberto; Jané, E; Sempau Roma, Josep; Falcón, C; Bullich, S; Pavía, J; Calviño Tavares, Francisco; Ros, D
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Other authors:
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Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear; Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques; Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions |
Abstract:
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3I is a commonly used radioisotope employed in
neurotransmitter SPECT studies. In addition to an intense line
at 159 keV, the decay scheme of this radioisotope includes a low
yield (∼3%) of higher energy photons which have a non-negligible
contribution to the final image when low-energy high-resolution
(LEHR) collimators are used. This contribution of high-energy
photons may achieve ∼28% of the total counts in the projections.
The aim of this work is to model each energy component of
the high-energy Point Spread Function (hPSF) for fan-beam
LEHR collimators in order to develop faster Monte Carlo (MC)
simulations of high-energy ray contamination. The modelling of
hPSF was based on the results of simulating photons through
the collimator-detector system using the MC code PENELOPE.
Since low-energy PSFs models for fan-beam collimators must
tend to a Gaussian distribution, we use the same function for
the hPSF modelling for high-energy photons. The parameters of
these Gaussian functions were obtained by minimizing the root
mean square (RMS) error between each simulated hPSF and the
function g(x, y) using the efficiency of the simulated hPSFs as a
constraint. The RMS attained with fit of g(x, y) to the simulated
hPSFs was always smaller than ∼2% of the mean efficiency per
pixel of the image. A very strong dependence of the efficiency
on the type and thickness of the backscatter material behind the
crystal was found. The hPSFs were parameterized for a wide
range of energies, ranging from 350 keV to 538 keV. Our results
indicate that Gaussian distributions approximate in a suitable way
the hPSF responses for fan-beam collimators. This model will be
an important tool to accelerate MC simulations of radiolabelled
compounds which emit medium- or high-energy rays. |
Abstract:
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Peer Reviewed |
Subject(s):
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-Monte Carlo, Mètode de -Contaminació radioactiva |
Rights:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
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Article - Published version Conference Object |
Published by:
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IEEE
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