National variation of PET/CT performance, quality control standards and adherence to imaging guidelines in Austria

Objectives To gather information on clinical operations, quality control (QC) standards and acceptance of European guidelines for imaging in Austrian PET/CT centres.

Methods A written survey composed of 68 questions related to A) PET/CT centre and installation, B) FDG oncology imaging protocols and C) standard QC procedures was conducted between November and December of 2013 among all 12 Austrian PET/CT centres. In addition, a NEMA-NU2 2012 image quality phantom test was performed using standard whole-body imaging settings on all PET/CT systems with a lesion-to-background ratio of 4. Recovery Coefficients (RC) were calculated for each lesion and scanner.

Results A) 13 PET/CT systems are installed in 12 Nuclear Medicine departments of public hospitals. 8/12 centres have min. 5-y experience in PET. Over 86% of PET/CT examinations are performed for oncology indications. B) Average fasting prior to FDG-PET/CT is 7.2 (4-12) h. All sites measure blood glucose levels while using different cut-offs (64%: 150 mg/dL). Weight-based activity injection is performed at 81% sites with a mean FDG activity of 4.1 MBq/kg. Avg. FDG uptake time is 55 (30-75) min. All sites employ CT contrast agents (variation from 1%-95% of the patients). All sites report SUVmax. C) QC phantom measurements revealed significant differences in RCs with the RCs being at the upper acceptance limit (Boellard [http://earl.eanm.org] 2011). The average values of RC_max for sphere diameter (mm) 37, 28, 22, 17, 13 and 10 were 1.14 (0.51-1.47), 1.11 (0.50-1.44), 1.06 (0.47-1.38), 0.98 (0.34-1.56), 0.77 (0.28-1.11) and 0.49 (0.20-0.79), respectively.

Conclusions Variations in FDG-PET/CT protocol parameters among all Austrian PET/CT users were observed, but less pronounced than those reported by Graham (JNM 2011) and Beyer (JNM 2011). However, standardized QC procedures need to be implemented to improve quantitative accuracy across the centres.

Research Support This survey was supported by the OGN