Purpose <p>This study aimed to comprehensively determine the radiation dose and image quality of rapid kVp-switching dual-energy CT (DECT) protocol for whole-abdominal emergency and compare its performance with a standard single-energy CT (SECT) protocol.</p> Methods <p>Retrospective data were collected from 130 patients who underwent contrast-enhanced whole-abdominal CT using either a fast kVp-switching DECT protocol (<i>n</i> = 65) or a routine SECT protocol (<i>n</i> = 65). Radiation dose in each protocol was determined using the volume CT dose index (CTDI_vol). Quantitative image quality was assessed by measuring the mean attenuation (HU) and image noise (standard deviation of HU) to calculate the signal-to-noise ratio (SNR) in the aorta, main portal vein (MPV), liver, spleen, and psoas muscle. Subjective image quality including diagnostic acceptability and image noise was assessed independently by two experienced emergency radiologists. The Mann–Whitney U test was used to compare differences between the DECT and SECT protocols.</p> Results <p>The average CTDI_vol obtained from SECT was higher than that from DECT; however, the difference was not statistically significant (10.7 ± 2.3 vs. 10.3 ± 2.8 mGy, <i>p</i> = 0.579). Although DECT demonstrated significantly higher signal and noise levels across all measured structures (<i>p</i> &lt; 0.05), SNR values were not significantly different between protocols, except for the MPV (<i>p</i> = 0.016). Subjective assessments showed no significant differences in diagnostic acceptability or image noise (<i>p</i> &gt; 0.05).</p> Conclusion <p>Fast kVp-switching DECT demonstrates comparable radiation dose and image quality to SECT in patients undergoing CT for acute abdominal conditions in the emergency department. These findings suggest that DECT may be considered as an alternative CT imaging technique in the emergency abdominal setting.</p>