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Metrard G, Cohen C, Bailly M. Comprehensive literature review of oral and intravenous contrast-enhanced PET/CT: a step forward? Front Med (Lausanne) 2024; 11:1373260. [PMID: 38566921 PMCID: PMC10985176 DOI: 10.3389/fmed.2024.1373260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
The integration of diagnostic CT scans into PET/CT facilitates a comprehensive single examination, presenting potential advantages for patients seeking a thorough one-shot check-up. The introduction of iodinated contrast media during PET scanning raises theoretical concerns about potential interference with uptake quantification, due to the modification of tissue density on CT. Nevertheless, this impact appears generally insignificant for clinical use, compared to the intrinsic variability of standardized uptake values. On the other hand, with the growing indications of PET, especially 18F-FDG PET, contrast enhancement increases the diagnostic performances of the exam, and provides additional information. This improvement in performance achieved through contrast-enhanced PET/CT must be carefully evaluated considering the associated risks and side-effects stemming from the administration of iodinated contrast media. Within this article, we present a comprehensive literature review of contrast enhanced PET/CT, examining the potential impact of iodinated contrast media on quantification, additional side-effects and the pivotal clinically demonstrated benefits of an all-encompassing examination for patients. In conclusion, the clinical benefits of iodinated contrast media are mainly validated by the large diffusion in PET protocols. Contrary to positive oral contrast, which does not appear to offer any major advantage in patient management, intravenous iodine contrast media provides clinical benefits without significant artifact on images or quantification. However, studies on the benefit-risk balance for patients are still lacking.
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Affiliation(s)
- Gilles Metrard
- Nuclear Medicine Department, Orléans University Hospital, Orléans, France
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Université d’Orléans, Orléans, France
| | - Clara Cohen
- Radiology Department, Orléans University Hospital, Orléans, France
| | - Matthieu Bailly
- Nuclear Medicine Department, Orléans University Hospital, Orléans, France
- Centre de Biophysique Moléculaire, CNRS UPR 4301, Université d’Orléans, Orléans, France
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Li C, Scheins J, Tellmann L, Issa A, Wei L, Shah NJ, Lerche C. Fast 3D kernel computation method for positron range correction in PET. Phys Med Biol 2023; 68. [PMID: 36595256 DOI: 10.1088/1361-6560/acaa84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/09/2022] [Indexed: 12/13/2022]
Abstract
Objective. The positron range is a fundamental, detector-independent physical limitation to spatial resolution in positron emission tomography (PET) as it causes a significant blurring of underlying activity distribution in the reconstructed images. A major challenge for positron range correction methods is to provide accurate range kernels that inherently incorporate the generally inhomogeneous stopping power, especially at tissue boundaries. In this work, we propose a novel approach to generate accurate three-dimensional (3D) blurring kernels both in homogenous and heterogeneous media to improve PET spatial resolution.Approach. In the proposed approach, positron energy deposition was approximately tracked along straight paths, depending on the positron stopping power of the underlying material. The positron stopping power was derived from the attenuation coefficient of 511 keV gamma photons according to the available PET attenuation maps. Thus, the history of energy deposition is taken into account within the range of kernels. Special emphasis was placed on facilitating the very fast computation of the positron annihilation probability in each voxel.Results. Positron path distributions of18F in low-density polyurethane were in high agreement with Geant4 simulation at an annihilation probability larger than 10-2∼ 10-3of the maximum annihilation probability. The Geant4 simulation was further validated with measured18F depth profiles in these polyurethane phantoms. The tissue boundary of water with cortical bone and lung was correctly modeled. Residual artifacts from the numerical computations were in the range of 1%. The calculated annihilation probability in voxels shows an overall difference of less than 20% compared to the Geant4 simulation.Significance. The proposed method is expected to significantly improve spatial resolution for non-standard isotopes by providing sufficiently accurate range kernels, even in the case of significant tissue inhomogeneities.
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Affiliation(s)
- Chong Li
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany.,Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Jürgen Scheins
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany
| | - Lutz Tellmann
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany
| | - Ahlam Issa
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany.,JARA-BRAIN-Translational Medicine, RWTH Aachen University, Aachen, Germany
| | - Long Wei
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - N Jon Shah
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany.,Institute of Neuroscience and Medicine, INM-11, Forschungszentrum GmbH, Jülich, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany.,JARA-BRAIN-Translational Medicine, RWTH Aachen University, Aachen, Germany
| | - Christoph Lerche
- Institute of Neuroscience and Medicine, INM-4, Forschungszentrum GmbH, Jülich, Germany
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