PET image reconstruction and dosimetry from voxelized phantoms with GATE

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2024-09, Vol.222, p.111833, Article 111833
• Main Authors: Lorduy-Alós, María, Avelino de Andrade, Pedro H., Peña-Acosta, Miriam Magela, Gallardo, Sergio, Verdú, Gumersindo
• Format: Article
• Language: English
• Subjects: 3D computational phantoms; GATE; Monte Carlo; Patient-specific dosimetry; S-Values
• ISSN: 0969-806X
• DOI: 10.1016/j.radphyschem.2024.111833

Accurate patient-specific internal dosimetry is a critical concern in the field of nuclear medicine. GATE is a robust Monte Carlo toolkit renowned for its integration of Geant4 algorithms, PET specialized tools and patient-specific dosimetry estimation. In this work, a GATE model is developed to simulate the PET scanner Biograph Vision and a voxelized phantom from Computed Tomography (CT) images. The segmentation of the CT images is performed using a deep learning model capable of automatically delineating anatomical structures, setting the basis for creating the patient-specific voxel phantom. GATE Nested parameterization method is employed for its efficient memory usage in defining geometry and faster navigation for ultra-large number of voxels. Simultaneously, PET acquisition data is used to assign the corresponding activity of a source to each voxel. This study aims to highlight the potential of GATE as a simulation tool within a methodology that integrates PET image reconstruction and internal dosimetry calculation, focused specifically on its application in prostate diagnostic testing via 18F-FDG. S-Value and dose are calculated for the prostate gland, yielding values of 1.52 E−4 mGy/MBq‧s and 8.1 mGy, respectively, consistent with literature findings. Differences in S-Values with the ICRP Phantom and with OpenDose for surrounding organs range from 0.5% to 67.9%, which can be attributed to the choice of phantoms used in calculations. This work confirms the capability of GATE to reproduce clinical studies using anthropomorphic voxelized models. •GATE toolkit is used for accurate CT/PET modeling and patient dosimetry estimation.•Deep learning allows the automatic segmentation of CT images.•Prostate and Organs at risk S-values and dose are obtained.•A methodology integrating PET reconstruction and dosimetry calculation is performed.