Impact of high densities induced by iodine-based contrast media. On NEMA NU 4 image quality phantom measurements (a) and SA-PET/CT quantitative values (b). (a) Representative coronal slices of the NEMA NU 4 image quality phantom at the level of the water- and air-filled cylinders are shown (left panel). Percentage standard deviation (%SDunif) and spillover ratios in water (SORwat) and in air (SORair) are shown in the right panel for the phantom filled with an 18F-FDG solution (blue) or a mixture of 18F-FDG and iodinated contrast media at a final concentration of 100 mg I/mL (red). PET data were reconstructed with both attenuation and scatter corrections, with only attenuation correction and with neither attenuation nor scatter correction. (b) Ratios of measured and true activity for 18F-FDG sources surrounded by water or by a combination of water and iodine layers (four consecutive measurements were performed; bars denote mean ± %SD). Transverse sections through the homemade phantom are shown, illustrating the different parts of the phantom: small tubes (diameter 10 mm) filled with an 18F-FDG-containing solution and placed at the center of a syringe (diameter 18 mm) filled either with water or with a solution of iohexol (100 mg I/mL) inserted into a second syringe (diameter 27 mm).