Is fluoroscopy necessary during flexible ureteroscopy for the treatment of renal stones?

clinically insignificant residual fragment; CT: computed tomography; EAU: European Association of Urology; (f)fURS: (fluoroless) flexible ureteroscopy; FT: fluoroscopy time; KUB: plain abdominal radiograph of the kidneys, ureters and bladder; mSv: millisievert; PCNL: percutaneous nephrolithotomy; pps: pulse-per-second; rem: roentgen equivalent man; PUJ: pelvi-ureteric junction; SFR: stone-free rate.