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

Abstract

Objectives To define reference levels for intraoperative radiation during stent insertion, ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL); to identify variation in radiation exposure between individual hospitals across the UK, between low‐ and high‐volume PCNL centres, and between grade of lead surgeon. Patients/Subjects and Methods In all, 3651 patients were identified retrospectively across 12 UK hospitals over a 1‐year period. Radiation exposure was defined in terms of total fluoroscopy time (FT) and dose area product (DAP). The 75th percentiles of median values for each hospital were used to define reference levels for each procedure. Results Reference levels: ureteric stent insertion/replacement (DAP, 2.3 Gy/cm2; FT, 49 s); URS (DAP, 2.8 Gy/cm2; FT, 57 s); PCNL (DAP, 24.1 Gy/cm2; FT, 431 s). Significant variations in the median DAP and FT were identified between individual centres for all procedures (P < 0.001). For PCNL, there was a statistically significant difference between DAP for low‐ (<50 cases/annum) and high‐volume centres (>50 cases/annum), at a median DAP of 15.0 Gy/cm2 vs 4.2 Gy/cm2 (P < 0.001). For stent procedures, the median DAP and FT differed significantly between grade of lead surgeon: Consultant (DAP, 2.17 Gy/cm2; FT, 41 s) vs Registrar (DAP, 1.38 Gy/cm2; FT, 26 s; P < 0.001). Conclusion 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.

Patient exposure and diagnostic reference levels in operating rooms: a multi-centric retrospective study in over 150 private and public French clinics

“…Firstly, figures 1-3 and table 2 indicate that exposure in OR can be significantly different from one centre to another for an identical type of procedure with up to two orders of magnitude difference in P KA for hand/wrist fractures for instance. Such a large variability was also reported by Simson et al [22] and by Hardman et al [25] who identified variation in radiation exposure between low and high-volume centres as well as between grades of lead surgeons (consultant vs. registrar) with the senior officers responsible for the more complex cases showing highest exposure levels.…”

“…Although private clinics often have a high load of patients and surgeries performed by consultants, public/university hospitals treat the more complex/severe cases and also offer training opportunities for interns and early career surgeons which could explain the similar exposure levels. Operator experience, training and radiation protection awareness may also largely affect patient exposure and explain such results [21,22,30,31]. The likely presence of a radiographer and imaging medical physicist in public hospitals could also benefit in reducing patient doses [21].…”

“…Additionally, some multi-center studies were also conducted to document exposure levels and DRLs for different practices. Namely, Simson et al collected data across 12 public UK hospitals deriving DRLs for 3 urological procedures [22]. Similarly, Tsapaki et al [23] investigated exposure during Endoscopic Retrograde Cholangiopancreatography procedures performed in fourhospitals (1 private) with four types of x-ray units.…”

Radiation exposure in emergency ureteric stenting: A subgroup analysis by operator

“…Radiation exposure in this study population of FT 44.5 s (IQR 44 s) and DAP 2.94 Gy/cm 2 (IQR 3.48 Gy/cm 2 ) met the UK multi‐centre FLASH study 9 reference standards of FT 49 s and DAP 2.3. Furthermore, this study demonstrated no significant difference comparing consultant to registrar FT or DAP, in comparison to the FLASH study, which identified a significant difference of DAP 2.17 Gy/cm 2 and FT 41 s for consultants and for registrars DAP 1.38 Gy/cm 2 FT 26 s. Our findings had comparable consultant values, but not registrar values with higher DAP and FT for registrars.…”

Personalized Prediction of Patient Radiation Exposure for Therapy of Urolithiasis: An Application and Comparison of Six Machine Learning Algorithms

“…In order to be able to classify and assess risk of exposure, threshold values for the intervention were necessary. Based on threshold values for urological interventions, which were evaluated in the large multicentre "FLASH" study, we assessed and classified whether there was an increased risk of radiation exposure for each intervention [22]. Accordingly, for ureterorenoscopy a cut-off value was set at 2.8 Gy•cm 2 (dose area product/DAP), i.e., low dose corresponds to ≤2.8 Gy•cm 2 and higher dose to >2.8 Gy•cm 2 .…”