ACRIPET · ACcurate Reconstruction In PET: Fully 3D PET reconstruction with compressed scatter system matrix

In the fight against cancer, Positron Emission Tomography (PET) can provide 3D images of metabolic processes (i.e. of cells in action) in the body and contributes to diagnosis and treatment. Two-dimensional PET scanners (2D PET) have been replaced by three-dimensional PET machines combined with a CT (3D PET/CT). This led to complementary anatomical information (from the CT) and increased sensitivity (less noise in the images). However, the increased sensitivity comes along with an increased detection of scattered radiations that impair accurate quantitative measurements necessary for diagnosis and follow-up. PET images are usually reconstructed iteratively from the signal detected by the scanner using a system matrix that models the imaging process. In clinical 3D PET/CT, this huge system matrix (order of Terabytes) is highly simplified to make the problem tractable. Based on previous proof-of-principle studies in 2D PET by the applicant, the ACRIPET project proposes to develop a novel and accurate 3D reconstruction method based on an accurate (unlike approximate) system matrix obtained through Monte Carlo modelling of all patient and detector related effects interfering with the imaging process. The method uses compression schemes to reduce Monte Carlo noise and allow storage of the system matrix. These compression schemes will be extended to 3D PET and parallelized on multi node computer architecture to make accurate 3D PET reconstruction clinically feasible. By using the most modern computer resources to fully exploit the potential of 3D PET/CT scanners, PET image accuracy should be significantly increased, contributing to earlier detection and more precise characterization of the disease and of its evolution. The host laboratory has a high expertise and recognition in all fields involved the project and will contribute to enhance the researcher professional maturity for the development of his career in the field.