J Nucl Med. 2008; 49 (Supplement 1):405P
Instrumentation & Data Analysis: InstrumentationInstrumentation Posters |
Validation of a GATE model of the Siemens Symbia system for 99mTc, 111In and 131I acquisitions
Thomas Carlier1,
Maxime Moisan3,
Ludovic Ferrer2,
Francoise Kraeber-Bodere1,
Jacques Barbet3 and
Manuel Bardies3
1 Nuclear Medicine, University Hospital of Nantes, Nantes, France;
2 Medical Physics, Cancer Center, Nantes, France;
3 INSERM Unit 601, Nantes, France
1704
Objectives: This study aims at validating a Monte-Carlo model of the Siemens Symbia SPECT system for 3 different isotopes (99mTc, 111In and 131I) with the GATE simulation platform.
Methods: Monte-Carlo simulations were conducted using the Geant4 Application for Emission Tomography (GATE) toolkit and compared with experimental data. Four figures of merit were used for comparison purpose: energy spectrum in air (point source with and without the collimator) and water (uniform cylinder of 21 cm diameter), sensitivity (as described by NEMA NU 1-2000) and spatial resolution measured with a line source at 5, 10, 15 and 20 cm from the surface of the collimator.
Results: Good agreement was found between all spectra (acquired and simulated) and for all isotopes, except for 111In where an overestimation (22 %) of the simulated vs. acquired counts was observed for the 245 keV peak, for both collimated and uncollimated detector. The difference in sensitivity between experiment and simulation was always less than 11 % (see the Table). Spatial resolutions calculated from simulations were close from experimental values: relative differences less than 8 % (99mTc), 10 % (111In) and 9 % (131I) were obtained.
Conclusions: We created and validated a GATE model of the Siemens Symbia SPECT system for use with 99mTc, 111In or 131I simulations. Small discrepancies observed for 111In acquisitions need to be further studied to accurately reproduce the energy spectrum of the system.
