Program Information
Image-Quality-Based Quantitative Assessment of Dose Reduction in 18F-FDG PET/MRI Examinations in Pediatric Oncology
M Branchini1*, P Zucchetta2 , A Zorz3 , V Bodanza4 , D Cecchin5 , F Bui6 , M Paiusco7 , (1) Veneto Institute of Oncology IOV - IRCCS, Padua, Italy, (2) University-Hospital of Padova, Padua, Italy, (3) Veneto Institute of Oncology IOV - IRCCS, Padua, Italy, (4) University-Hospital of Padova, Padua, Italy, (5) University-Hospital of Padova, Padua, Italy, (6) University-Hospital of Padova, Padua, Italy, (7) Veneto Institute of Oncology IOV - IRCCS, Padua, Italy
Presentations
WE-F-201-7 (Wednesday, August 2, 2017) 1:45 PM - 3:45 PM Room: 201
Purpose: the aim of this study was to evaluate the feasibility of administered activity reduction in 18F-FDG PET/MR examination of pediatric oncology patients on the basis of the effects on image quality.
Methods: 21 18F-FDG-PET/MRI whole-body examinations performed on a 3-Tesla clinical PET/MR hybrid scanner (Biograph mMR, Siemens Healthcare) were analyzed. Activity reduction was simulated by truncating the original list-mode data (3 MBq/kg, 5 min/bed position) at 4, 3, 2.5, 2 and 1 minutes with Siemens e7-tools (figure 1). Image quality (perceived IQ and number of detected lesions) was assessed independently by two expert nuclear medicine physicians and image metrics were calculated. In particular, SUV statistics (mean, max, peak), contrast-to-noise ratio (CNR), normalized noise in liver (NN), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were evaluated in VOI segmented on each image with 40% of SUVmax threshold.
Results: all the total 56 lesions were detected till bed time 2 min, whereas 5 lesions were missed on the 1 min image. Differences for SUVmax and SUVmean remained below 5% in 4, 3, 2.5, and 2 min images, with a +10% and +9% in the 1 min image while average differences for SUVpeak were less than 2% (figure 2). NN showed a constant increase up to +100% in the 1 min acquisition. Quantitative analyses yielded consistent results (figure 3): CNR, MTV and TLG differences were not statistically different for bed times of 4, 3 and 2.5 min (pairwise paired Wilcoxon and t-tests).
Conclusion: a dose reduction up to 50% (1.5 MBq/kg) is feasible in pediatric oncology patients while preserving lesions’ detectability and quantitative tumor burden information.
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