探讨低剂量CT尿路成像（CTU）辅助定位行经皮肾镜碎石取石术（PCNL）的可行性。

选取10例需行PCNL治疗的上尿路结石患者，采用自身对照，所有患者均于排泄期先行常规剂量（250 mA）CT扫描，然后即刻行低剂量（50 mA）扫描，两组图像进行独立评估上尿路结石征象、肾积水程度、肾周组织器官情况和定位参数（穿刺角度、穿刺深度），对两组数据进行统计学分析。

两组图像均能满足影像学诊断。以常规剂量CTU图像为参照标准，低剂量CTU对结石征象、肾周组织情况的显示率为100%。低剂量和常规剂量CTU在定位参数、肾盏形态构象方面比较差异无统计学意义（P>0.05），而在有效辐射量方面差异有统计学意义（P<0.01）。

对适合行PCNL治疗的上尿路结石患者，在应用CTU扫描定位时，可以以低剂量CTU扫描取代常规剂量CTU扫描作为常规首选的定位方法，能有效降低患者围手术期的放射辐射量。

To explore the feasibility of low-dose CT urography-assisted positioning of PCNL.

Ten patients with upper urinary calculi requiring PCNL treatment were selected. All patients underwent conventional dose (250 mA) CT in excretion and then low dose (50 mA) scan was taken immediately. Signs of upper urinary tract calculi, degree of hydronephrosis, situation of perirenal tissues and organs and location parameters (angle of puncture, depth of puncture) of the two groups of images were assessed independently; statistical analysis was conducted on the two groups of data.

The two groups of images could meet the imaging diagnosis. Regarding conventional dose CTU image as the reference standard, low dose CTU could show the signs of calculi and situation of perirenal tissues completely. Low dose and conventional dose CTU presented no statistically significant difference (P>0.05) in location parameters and conformation of renal calyx, but in effective radiation (P<0.01).

For patients with upper urinary calculi who are suitable for PCNL treatment, low dose CTU scan can substitute for conventional dose CTU scan and become the preferred location method when CTU scan is applied, and it can effectively reduce the radiation level in patients during perioperative period.