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Purpose: This study aimed to investigate the impact of a deep learning (DL)-based denoising method on the image quality and lesion detectability of 18F-FDG positron emission tomography (PET) images. Methods: Fifty-two oncological patients undergoing an 18F-FDG PET/CT imaging with an acquisition of 180 s per bed position were retrospectively included. The list-mode data were rebinned into four datasets: 100% (reference), 75%, 50%, and 33.3% of the total counts, and then reconstructed by OSEM algorithm and post-processed with the DL and Gaussian filter (GS). The image quality was assessed using a 5-point Likert scale, and FDG-avid lesions were counted to measure lesion detectability. Standardized uptake values (SUVs) in livers and lesions, liver signal-to-noise ratio (SNR) and target-to-background ratio (TBR) values were compared between the methods. Subgroup analyses compared TBRs after categorizing lesions based on parameters like lesion diameter, uptake or patient habitus. Results: The DL method showed superior performance regarding image noise and inferior performance regarding lesion contrast in the qualitative assessment. More than 96.8% of the lesions were successfully identified in DL images. Excellent agreements on SUV in livers and lesions were found. The DL method significantly improved the liver SNR for count reduction down to 33.3% (p < 0.001). Lesion TBR was not significantly different between DL and reference images of the 75% dataset; furthermore, there was no significant difference either for lesions of > 10 mm or lesions in BMIs of > 25. For the 50% dataset, there was no significant difference between DL and reference images for TBR of lesion with > 15 mm or higher uptake than liver. Conclusions: The developed DL method improved both liver SNR and lesion TBR indicating better image quality and lesion conspicuousness compared to GS method. Compared with the reference, it showed non-inferior image quality with reduced counts by 25–50% under various conditions. [ABSTRACT FROM AUTHOR]

This study was to investigate the synthesis and biological evaluation of [99mTc]Tc-labeled Buthus martensii Karsch Chlorotoxin ([99mTc]Tc-BmK CT) as a radiopharmaceutical for glioma single photon computed emission tomography (SPECT) imaging. The results showed that BmK CT peptide modified with a hexahistidine tag displayed good cytocompatibility in vitro, and could be efficiently radiolabeled with 99mTc via [99mTc]Tc-tricarbonyl chemistry. The [99mTc]Tc-BmK CT showed satisfactory radiochemical purity and stability in vitro, and could be developed as a probe for targeted SPECT imaging of glioma cells in vitro and in a tumor-bearing mouse model. Our data indicated that the synthesized [99mTc]Tc-BmK CT might be developed as a promising imaging agent for glioma diagnostic application. [ABSTRACT FROM AUTHOR]

Objective. We conducted a meta-analysis to evaluate the predictive value of interim 18F-FDG PET/CT in patients with DLBCL treated with R-CHOP chemotherapy. Methods. We searched for articles published in PubMed, ScienceDirect, Wiley, Scopus, and Ovid database from inception to March 2014. Articles related to interim PET/CT in patients with DLBCL treated with R-CHOP chemotherapy were selected. PFS with or without OS was chosen as the endpoint to evaluate the prognostic significance of interim PET/CT. Results. Six studies with a total of 605 cases were included. The sensitivity of interim PET/CT ranged from 21.2% to 89.7%, and the pooled sensitivity was 52.4%. The specificity of interim PET/CT ranged from 37.4% to 90.7%, and the pooled specificity was 67.8%. The pooled positive likelihood ratio and negative likelihood ratio were 1.780 and 0.706, respectively. The explained AUC was 0.6978 and the Q* was 0.6519. Conclusions. The sensitivity and specificity of interim PET/CT in predicting the outcome of DLBCL patients treated with R-CHOP chemotherapy were not satisfactory (52.4% and 67.8%, resp.). To improve this, some more work should be done to unify the response criteria and some more research to assess the prognostic value of interim PET/CT with semiquantitative analysis. [ABSTRACT FROM AUTHOR]

We evaluated the predictive value of [18F]fluoro-2-deoxy- d-glucose positron emission tomography (FDG-PET) for clinical outcome such as progression-free survival (PFS) and overall survival (OS) in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) prior to and after autologous stem cell transplant (ASCT). FDG-PET/computed tomography (CT) was performed in 39 consecutive patients with relapsed/refractory DLBCL scheduled for ASCT. The median follow-up of surviving patients was 3 years (range 19-66 months). Both pre- and post-ASCT, FDG-PET findings were strongly correlated with PFS and OS ( p < 0.005). The 2-year PFS estimates for FDG-negative versus -positive patients were 84.8% vs. 36.8% (pre-) and 81.1% vs. 13.3% (post-). The 2-year OS estimates in these groups were 95.5% vs. 68.3% (pre-) and 92.7% vs. 57.1% (post-). Patients were classified into three groups according to FDG-PET results before and after ASCT. The median PFS was significantly lower in the +/+ group (13.0 months) as compared with the +/− group (31.0 months, p = 0.021) and the −/− group ( p = 0.000). The regression model showed that the predictive value of FDG-PET before ASCT owed its significance to a very high hazard ratio between patients with positive and negative imaging ( p < 0.01). FDG-PET prior to and following ASCT in patients with relapsed or refractory DLBCL contains prognostic information on long-term clinical outcome. [ABSTRACT FROM AUTHOR]