PET digitization chain for Monte Carlo simulation in GATE

Julien Salvadori (1) , Antoine Merlet (2) , Benoit Presles (2) , Jorge Cabello (3) , Kuan-Hao Su (4) , Alexandre Cochet (2) , Ane Etxebeste (5, 6) , Jean-Marc Vrigneaud (7, 8) , David Sarrut (5, 6)

1 ICANS - Institut de Cancérologie de Strasbourg Europe
2 ICMUB - Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon]
3 Siemens Medical Solutions USA, Inc. [Knoxville, TN, USA]
4 UNICANCER/CRLCC-CGFL - Centre Régional de Lutte contre le cancer Georges-François Leclerc [Dijon]
5 CREATIS - Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé
6 Imagerie Tomographique et Radiothérapie
7 CGFL - Service de Médecine Nucléaire, Centre Georges-François Leclerc [Dijon]
8 Equipe IFTIM [ImViA - EA7535]

Abstract Objective . We introduce a versatile methodology for the accurate modelling of PET imaging systems via Monte Carlo simulations, using the Geant4 application for tomographic emission (GATE) platform. Accurate Monte Carlo modelling involves the incorporation of a complete analytical signal processing chain, called the digitizer in GATE, to emulate the different count rates encountered in actual positron emission tomography (PET) systems. Approach . The proposed approach consists of two steps: (1) modelling the digitizer to replicate the detection chain of real systems, covering all available parameters, whether publicly accessible or supplied by manufacturers; (2) estimating the remaining parameters, i.e. background noise level, detection efficiency, and pile-up, using optimisation techniques based on experimental single and prompt event rates. We show that this two-step optimisation reproduces the other experimental count rates (true, scatter, and random), without the need for additional adjustments. This method has been applied and validated with experimental data derived from the NEMA count losses test for three state-of-the-art SiPM-based time-of-flight (TOF)-PET systems: Philips Vereos, Siemens Biograph Vision 600 and GE Discovery MI 4-ring. Main results . The results show good agreement between experiments and simulations for the three PET systems, with absolute relative discrepancies below 3%, 6%, 6%, 7% and 12% for prompt, random, true, scatter and noise equivalent count rates, respectively, within the 0–10 kBq·ml −1 activity concentration range typically observed in whole-body 18 F scans. Significance . Overall, the proposed digitizer optimisation method was shown to be effective in reproducing count rates and NECR for three of the latest generation SiPM-based TOF-PET imaging systems. The proposed methodology could be applied to other PET scanners.

Mots clés: PET GATE Monte-Carlo simulation digitizer; PET; GATE; Monte-Carlo simulation; digitizer

Domaines: Physique Médicale [physics.med-ph]

Julien Salvadori, Antoine Merlet, Benoit Presles, Jorge Cabello, Kuan-Hao Su, et al.. PET digitization chain for Monte Carlo simulation in GATE. Physics in Medicine and Biology, 2024, 69 (16), pp.165013. ⟨10.1088/1361-6560/ad638c⟩. ⟨hal-04746290⟩