Table 1.

Patient and operative characteristics

Variables	n = 100 Patients
Age, mean (range, SD), y	52.7 (19.9–82.4, 15.4)
Sex
Male	59
Female	41
BMI, mean (range, SD), kg/m²	30.8 (15.2–61.6, 8.9)
AP midline distance, mean (range, SD), cm	26.2 (17.5–44.6, 5.2)
AP transrenal distance, mean (range, SD), cm	25.8 (16.2–45.2, 5.1)
CT scout ROI, mean (range, SD), HU	615 (407–995, 107)
Laterality
Left	60
Right	33
Bilateral	7
Presence of preoperative stent	40
Associated hydronephrosis	64
Stone impaction	33
Stone location (s)
Renal	47
Proximal/mid ureter	18
Distal ureter	13
Multiple locations	17
No stone found	5
Use of ureteral access sheath	11
Ureteroscope type
Flexible	66
Semirigid	15
Both	14
Operative time, mean (range, SD), min	62 (21–160, 29)
Fluoroscopy time, mean (range, SD), s	4.2 (0.4–34.5, 6.0)
Displayed AK, mean (range, SD), mGy	1.2 (0.1–17.5, 2.1)
AK rate, mean (range, SD), mGy/s	0.30 (0.07–1.14, 0.23)
BMI <25 kg/m²	0.16 (0.07–0.34, 0.08)
25 to <30 kg/m²	0.25 (0.08–1.00, 0.19)
30 to <35 kg/m²	0.31 (0.11–0.72, 0.16)
≥35 kg/m²	0.50 (0.13–1.14, 0.29)
ESD, mean (range, SD), mGy	1.2 (0.1–18.0, 2.2)
ED, mean (range, SD), mSv	0.08 (0.01–1.20, 0.15)
ED rate, mean (range, SD), mSv/s	0.021 (0.005–0.078, 0.016)

AK, air kerma; AP, anterior-posterior; BMI, body mass index; CT, computed tomography; ED, effective dose; ESD, entrance skin dose; HU, hounsfield units; ROI, region of interest; SD, standard deviation.