Títol:
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Modeling of high-energy contamination in SPECT Imaging using Monte Carlo Simulation
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Autor/a:
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Cot Sanz, Alberto; Jané, E; Sempau Roma, Josep; Falcón, C; Bullich, S; Pavía, J; Calviño Tavares, Francisco
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Altres autors:
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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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I 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 make a
non-negligible contribution to the final image when low-energy
high-resolution (LEHR) collimators are used. This contribution
of high-energy photons may reach 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 fast Monte
Carlo (MC) simulations of high-energy ray contamination. The
modeling 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
tend to a Gaussian distribution, we use the same function for
the hPSF modeling for high-energy photons. The parameters of
these Gaussian functions ( ( )) were obtained by minimizing
the root mean square error (RMS) using the sensitivity of the
simulated hPSFs as a constraint. The hPSFs were parameterized
for a range of energies between 350 keV and 538 keV. The RMS
attained after fitting of ( ) to the simulated hPSFs was always
smaller than 2% of the mean sensitivity per pixel of the image.
A strong dependence of the sensitivity on the type and thickness
of the backscatter material behind the crystal was found. Our
results indicate that Gaussian distributions approximate the hPSF
responses for fan-beam collimators. This model will be an important
tool to accelerate MC simulations of radiolabeled compounds
which emit medium- or high-energy rays. |
Abstract:
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Peer Reviewed |
Matèries:
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-Àrees temàtiques de la UPC::Energies::Tecnologia energètica -Monte Carlo method -Monte Carlo, Mètode de |
Drets:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Tipus de document:
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Article - Versió publicada Article |
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