Defining a national reference level for intraoperative radiation exposure in urological procedures: FLASH, a retrospective multicentre UK study.

This multicentre study is the largest of its kind. It provides the first national reference level to guide fluoroscopy use in urological procedures, thereby adding a quantitative and objective value to complement the principles of keeping radiation exposure 'as low as reasonably achievable'. This snapshot of real-time data shows significant variation around the country, as well as significant differences between low- and high-volume centres for PCNL, and grade of lead surgeon for stent procedures.