Effects of source-to-image distance and dose mode on image quality and radiation dose in high-definition (Hi-Def) angiography

This study evaluated the effects of source-to-image distance (SID) and dose mode on image quality and radiation dose in a high-definition (Hi-Def) angiography compared with conventional flat-panel detector (FPD). A phantom study was performed with varying SID (90–120 cm) and dose mode (low, normal, high). Fluoroscopy images were assessed using standard deviation (SD), contrast-to-noise ratio (CNR), air kerma rate, and spatial resolution (visual assessment). SD increased with SID in both systems, but Hi-Def exhibited more stable noise performance compared with FPD. Increasing SID reduced spatial resolution and increased air kerma rate in Hi-Def. CNR improved with increasing dose mode, whereas spatial resolution showed no significant differences. These results demonstrate that Hi-Def imaging exhibits unique characteristics, including increased radiation dose and SID-sensitive spatial resolution. Optimizing SID and dose mode is essential to preserve spatial resolution, avoid unnecessary radiation exposure, and achieve a balance between image quality and dose in Hi-Def.