Validation of a Monte Carlo simulation of the Philips Allegro/GEMINI PET systems using GATE

Abstract

A newly developed simulation toolkit, GATE (Geant4 Application for Tomographic Emission), was used to develop a Monte Carlo simulation of a fully three-dimensional (3D) clinical PET scanner. The Philips Allegro/GEMINI PET systems were simulated in order to (a) allow a detailed study of the parameters affecting the system's performance under various imaging conditions, (b) study the optimization and quantitative accuracy of emission acquisition protocols for dynamic and static imaging, and (c) further validate the potential of GATE for the simulation of clinical PET systems. A model of the detection system and its geometry was developed. The accuracy of the developed detection model was tested through the comparison of simulated and measured results obtained with the Allegro/GEMINI systems for a number of NEMA NU2-2001 performance protocols including spatial resolution, sensitivity and scatter fraction. In addition, an approximate model of the system's dead time at the level of detected single events and coincidences was developed in an attempt to simulate the count rate related performance characteristics of the scanner. The developed dead-time model was assessed under different imaging conditions using the count rate loss and noise equivalent count rates performance protocols of standard and modified NEMA NU2-2001 (whole body imaging conditions) and NEMA NU2-1994 (brain imaging conditions) comparing simulated with experimental measurements obtained with the Allegro/GEMINI PET systems. Finally, a reconstructed image quality protocol was used to assess the overall performance of the developed model. An agreement of <3% was obtained in scatter fraction, with a difference between 4% and 10% in the true and random coincidence count rates respectively, throughout a range of activity concentrations and under various imaging conditions, resulting in <8% differences between simulated and measured noise equivalent count rates performance. Finally, the image quality validation study revealed a good agreement in signal-to-noise ratio and contrast recovery coefficients for a number of different volume spheres and two different (clinical

Distributions of positron-emitting nuclei in proton and carbon-ion therapy studied with GEANT4

“…Our present study is focused on the ability of the GEANT4 toolkit to describe the production of positron-emitting nuclei rather then on modelling various aspects of PET measurements. As has been already demonstrated by Jan et al (2004), Schmidtlein et al (2006) and Lamare et al (2006), the GEANT4 toolkit is very successful in Monte Carlo simulations of commercial PET scanners.…”

“…The results on validation of the GEANT4 toolkit for proton therapy (Jiang and Paganetti 2004) and for therapy with electrons and photons (Carrier et al 2004, Larsson et al 2005 have been presented recently. A GEANT4-based application for emission tomography (GATE) was developed by the Open-GATE collaboration (Jan et al 2004) and successfully used in Monte Carlo simulations of commercial PET scanners (Schmidtlein et al 2006, Lamare et al 2006. The GEANT4 toolkit is also used for simulations in brachytherapy (Enger et al 2006, Perez-Calatayud et al 2006.…”

Pretreatment 18F-FAZA PET Predicts Success of Hypoxia-Directed Radiochemotherapy Using Tirapazamine

“…The microPET uses OSEM for iterative image reconstruction instead of RAMLA on the MOSAIC scanner (42). However, both algorithms have similar performance characteristics (43).…”

Preclinical positron emission tomography scanner based on a monolithic annulus of scintillator: initial design study

“…It has been extensively validated and used in numerous projects to evaluate new PET scanner designs. [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] Without simulations, it is very challenging to explore new scanner designs, due to the cost and complexity of creating prototype systems intended solely for design evaluation purposes. AnnPET was modeled using the C-PET GATE scanner definition with a 6 ns coincidence timing window and 15% energy resolution; positron transport, Compton scattering, and photoelectric interactions were included in the model.…”