Daily quality control and cross-comparison of PET/CT imaging in clinical setting and for clinical trial

1308 Objectives PET/CT metabolic imaging using F-18 FDG is becoming increasingly used in oncology. Standardized uptake value (SUV) that reflects the metabolic activity measured within specific region of interest represents the most frequently used semi-quantitative parameter. Variability of those measurements may be related to the stability of the PET/CT scanner and the calibrator that determines the FDG activity injected. Our aim was to investigate intra-apparatus and inter-apparatus variability of SUV measurement. Methods Dedicated phantom filled with known and standardized amount of FDG solution was used. Reference base-line was calculated. Over a 5 months period, consecutive measurements were performed to calculate the long-term intrinsic reproducibility (CVi). Short-term CV (CVs) was calculated using dual daily measurements. Statistical CUSUM method was applied. Correction factors were calculated and automatic calibration correction factors (CCF) generated. Cross-calibration protocol was performed with 5 different PET/CT scanners and adequacy was demonstrated in measuring SUV of standardized normal tissue of reference. Results CVi was 0.17% (n=30) while CVs achieved 0.73%. Over a total number of 145 measurements, the statistical CUSUM method was applied and did not show any significant abnormality. The cross-calibration protocol performed with 5 different PET/CT scanners demonstrated that 4 out of 5 showed adequacy within a 5-10% range while 1 scanner demonstrated difference exceeding 20% in CCF. Conclusions These results consolidate the hypothesis that PET/CT scanners require daily quality control as other medical devices do. It also suggests that cross-calibration process would be valuable before comparing SUV measurements between PET/CT scanner or within clinical trials