Page 150 - Quantitative Imaging of Small Tumours with Positron Emission Tomography
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                                Introduction Positron-emission tomography (PET) enables in-vivo assessment of metabolic and intracellular processes. Whereas in clinical practice PET is predominantly used to qualitatively assess tracer uptake, PET(/CT) may also serve as a surrogate quantitative biomarker of, for example, tumour metabolism and proliferation. Interest into quantitative approaches of tumour assessment has grown considerably, for discriminating between benign and malignant lesions, staging, prognostication, and determining or predicting therapy response (1-4). Accurate quantification of metabolic volumes <2-3x the spatial resolution of PET is hampered by partial-volume effects, leading to underestimations of standardized uptake values (SUV), and possibly compromising lesion detection (5,6). Many methods for partial-volume correction (PVC) have been advocated (7). The simplest way is to use recovery coefficients obtained from phantom experiments, which assumes that true metabolic volume is known and that lesions are spherically shaped with homogeneous uptake. More sophisticated methods have been developed, but all suffer from limitations (7,8). Voxel-wise resolution recovery methods, incorporating the point spread function (PSF) within iterative reconstruction (9) (PSF reconstruction) or performing post-reconstruction 7 iterative deconvolution (10), could improve both qualitative and quantitative reads. To date, consensus on standardized application of PVC in oncological PET/CT studies is lacking, and perhaps as a consequence PVC is not yet routinely applied. In fact, most current clinical quantitative PET studies merely exclude small lesions (e.g. <2cm in diameter), as recommended in the PERCIST criteria (3). The clinical impact of PVC in oncological setting, and thus the need for standardized application, is not yet fully elucidated (7). We performed a systematic review and meta-analysis to assess the impact of PVC in clinical PET studies, focusing on diagnosis, staging, prognostication, and response assessment. Materials and methods Search strategy This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A comprehensive search (Supplemental Tables 1 and 2, available at https://www. Systematic review and meta-analysis   149   


































































































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