目的 探究低电压、低碘对比剂 剂量在头颈CT血管造影(CTA)中的临床应 用。方法 按照随机数字表法将80例行 头颈CTA的患者分为常规组及双低组， 每组40例，常规组患者CTA对比剂剂量 为60mL，管电压为120kVp，双低组患者 CTA对比剂剂量为0.3ml/kg，管电压为 100kVp。记录两组受试者使用对比剂剂 量、剂量长度乘积(DLP)，计算体型特异 性剂量估计值(SSDE)，对两组图像进行 客观及主观评价。结果 双低组受试者对 比剂剂量、DLP、SSDE均显著低于常规组 (P<0.05)；双低组在左、右大脑中动脉 中的图片客观质量评分显著低于常规组 (P<0.05)；其他兴趣区图片质量评分组间 比较差异无统计学意义(P>0.05)；两组 受试者CTA图像质量主观评价及合格率差 异均无统计学意义(P>0.05)。结论 低电 压、低碘对比剂剂量可显著降低头颈部 CTA扫描辐射剂量及对比剂碘的用量，图 像质量可满足临床疾病诊断。

Objective To explore the clinical application of the dose of low-voltage and low-iodine contrast agents in head and neck CT angiography (CTA). Methods By the random number table method, 80 patients undergoing head and neck CTA were divided into routine group and double-low group, with 40 cases in each group. The contrast agent dose of CTA and the tube voltage in routine group were 60 mL and 120 kVp, respectively. Those in the double-low group were 0.3 ml/kg and 100 kVp, respectively. The dose of contrast agents used and dose-length product (DLP) in both groups were recorded, and the size-specific dose estimate (SSDE) was calculated. Images of both groups were evaluated objectively and subjectively. Results The dose of contrast agents, DLP and SSDE in the double-low group were significantly lower than those in the routine group (P<0.05). The objective image quality scores in the left and right middle cerebral arteries of the double-low group were significantly lower than those in the routine group (P<0.05). However, there was no significant difference in image quality score in other interest areas between groups (P>0.05). There was no significant difference in subjective evaluation and passing rate of CTA image quality between the two groups (P>0.05). Conclusion Lowvoltage and low-iodine contrast agent doses can significantly reduce the scanning radiation dose of head and neck CTA and the amount of contrast iodine. The image quality can meet the clinical diagnosis.