-
S Jan,
D Benoit,
E Becheva,
T Carlier,
F Cassol, P Descourt,
T Frisson,
L Grevillot,
L Guigues,
L Maigne,
C Morel,
Y Perrot,
N Rehfeld,
D Sarrut,
D R Schaart,
S Stute,
U Pietrzyk,
D Visvikis,
N Zahra,
I Buvat
[show abstract]
[hide abstract]
ABSTRACT: GATE (Geant4 Application for Emission Tomography) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. Dedicated to the modelling of planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET) acquisitions, this platform is widely used to assist PET and SPECT research. A recent extension of this platform, released by the OpenGATE collaboration as GATE V6, now also enables modelling of x-ray computed tomography and radiation therapy experiments. This paper presents an overview of the main additions and improvements implemented in GATE since the publication of the initial GATE paper (Jan et al 2004 Phys. Med. Biol. 49 4543–61). This includes new models available in GATE to simulate optical and hadronic processes, novelties in modelling tracer, organ or detector motion, new options for speeding up GATE simulations, examples illustrating the use of GATE V6 in radiotherapy applications and CT simulations, and preliminary results regarding the validation of GATE V6 for radiation therapy applications. Upon completion of extensive validation studies, GATE is expected to become a valuable tool for simulations involving both radiotherapy and imaging.
Physics in Medicine and Biology 01/2011; 56(4):881. · 2.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Among Monte Carlo simulation codes in medical imaging, the GATE simulation platform is widely used today given its flexibility and accuracy, despite long run times, which in SPECT simulations are mostly spent in tracking photons through the collimators. In this work, a tabulated model of the collimator/detector response was implemented within the GATE framework to significantly reduce the simulation times in SPECT. This implementation uses the angular response function (ARF) model. The performance of the implemented ARF approach has been compared to standard SPECT GATE simulations in terms of the ARF tables' accuracy, overall SPECT system performance and run times. Considering the simulation of the Siemens Symbia T SPECT system using high-energy collimators, differences of less than 1% were measured between the ARF-based and the standard GATE-based simulations, while considering the same noise level in the projections, acceleration factors of up to 180 were obtained when simulating a planar 364 keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a four-head SPECT simulation of a realistic Jaszczak phantom filled with iodine-131, with a resulting acceleration factor of 100. In conclusion, the implementation of an ARF-based model of collimator/detector response for SPECT simulations within GATE significantly reduces the simulation run times without compromising accuracy.
Physics in Medicine and Biology 05/2010; 55(9):N253-66. · 2.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To speed up Monte Carlo simulations of Single Photon Emission Computed Tomography (SPECT) scans using iodine-131, a tabulated modeling of the detector response has been incorporated within the GATE simulation toolkit, based on the use of the Angular Response Function (ARF). In this work, we validate the ARF methodology within GATE for I-131 simulations and demonstrate the practical feasibility of the simulation of I-131 SPECT patient acquisitions. The Siemens Symbia T equipped with a high energy collimator was considered. Planar acquisitions of I-131 point and plane sources in air were simulated using GATE without (sGATE) and with the ARF model (ARF-GATE). Profiles through the projections and root mean square differences (RMSD) between ARF-GATE and sGATE projections were calculated. The statistical distributions of the simulated projections were also investigated. A I-131 Lipiocis<sup>?</sup> SPECT scan was also simulated and the simulated and acquired projections were compared. Profiles across the ARF-GATE et sGATE projections agreed well for the point and plane sources, with RMSD of 9%, similar to those obtained between two independent sGATE projections. The ARF-GATE and sGATE projections were Poisson distributed. About 36 times less photons were needed with ARF-GATE than with sGATE to get images of equivalent statistical quality for the plane source. Overall, ARF-GATE produced images indistinguishable from the sGATE images in 140 less time. For the patient simulations, simulated projections of visually comparable quality as acquired projections were obtained in 100,000 s. The expected computational time efficiency was estimated at 90 when using ARF-GATE instead of sGATE. GATE including the ARF model makes it possible to speed up GATE simulations by a factor > 100 without loss of accuracy. Simulations of patient I-131 SPECT scans become feasible in about 2 days or less using reasonable computational resources (small cluster with at least 20 CPUs).
Nuclear Science Symposium Conference Record (NSS/MIC), 2009 IEEE; 12/2009
-
[show abstract]
[hide abstract]
ABSTRACT: In SPECT Monte Carlo simulations, the tracking process of photons inside the collimator is a very tedious and computationally demanding task. For example in the case of a low energy parallel-hole collimator only one in a thousand photons penetrating the collimator surface will be detected. In an attempt to significantly decrease the time associated with the collimator tracking process we implemented within GATE the methodology designed by X. Song et al which relies on the use of Angular Response Function (ARF) for the collimator/detector system. The Angular Response Function refers to the spatial distribution of photons detected for a given point source position. The strategy developed by Song relies on the use of different Monte Carlo codes such as MCNP and SIMSET in order on one hand to generate list mode files from which the ARFs are computed and on the other hand to compute the ARF tables from these list modes files.
Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 11/2008
-
[show abstract]
[hide abstract]
ABSTRACT: We present the status of the Geant4 Application for Emission Tomography (GATE) project, a Monte Carlo simulator for Single Photon Emission Computed Tomography (SPECT) and Positron annihilation Emission Tomography (PET). Its main features are reminded, including modelling of time dependent phenomena and versatile, user-friendly scripting interface. The focus of this manuscript will be on new developments introduced in the past 4 years. New results have been achieved in the fields of validation on real medical and research PET and SPECT systems, voxel geometries, digitisation, distributed computing and dosimetry.
Nuclear Physics B - Proceedings Supplements.
