Intravenous contrast-enhanced CT can be used for CT-based attenuation correction in clinical

Background: CT-based attenuation correction (CT-AC) using contrast-enhancement CT impacts 111 In-SPECT image quality and quantification. In this study we assessed and evaluated the effect. Methods: A phantom (5.15 L) was filled with an aqueous solution of In-111. Three SPECT/CT scans were performed: (A) no IV contrast, (B) with 100-mL IV contrast, and (C) with 200-mL IV contrast added. Scan protocol included a localization CT, a low-dose CT (LD), and a full-dose CT (FD). Phantom, LD and FD scan series were performed at 90, 120, and 140 kVp. Phantom data were evaluated looking at mean counts in a central volume.