Radiation exposure of patients during endourological procedures: IAEA-SEGUR study

Abstract

Fluoroscopy is increasingly used to guide minimally invasive endourological procedures and optimised protocols are needed to minimise radiation exposure while achieving best treatment results. This multi-center study of radiation exposure of patients was conducted by the South-Eastern European Group for Urolithiasis Research (SEGUR), in cooperation with the International Atomic Energy Agency. Seven clinical centers from the SEGUR group collected data for 325 procedures performed within a three-months period, including standard percutaneous nephrolithotomy (PCNL), mini PCNL, retrograde intrarenal surgery (RIRS), semirigid ureterorenoscopy (URS) and flexible URS. Data included: air kerma area product (P KA), air kerma at the patient entrance reference point (K a,r), fluoroscopy time (FT), number of radiographic images (N) and fluoroscopy pulse rate, as well as total procedure duration, size and location of stones. Data were centrally analysed and statistically compared. Median P KA values per center varied 2-fold for RIRS (0.80–1.79 Gy cm2), 7.1 fold for mini-PCNL (1.39–9.90 Gy cm2), 7.3 fold for PCNL (2.40–17.50 Gy cm2), 19 fold (0.13–2.51 Gy cm2) for semi-rigid URS and 29-fold for flexible URS (0.10–2.90 Gy cm2). Lower P KA and K a,r were associated with use of lower FT, N and lower fluoroscopy pulse rate. FT varied from 0.1 to 14 min, a small fraction of the total procedure time, ranging from 10 to 225 min. Higher N was associated with higher P KA and K a,r. Higher median P KA in PCNL was associated with the use of supine compared to prone position. No correlation was found between the concrement size and procedure duration, FT, P KA or K a,r. Dose values for RIRS were significantly lower compared to PCNL. The maximum K a,r value of 377 mGy was under the threshold for radiation induced skin erythema. The study demonstrated a potential for patient dose reduction by lowering FT and N, using pulsed fluoroscopy and beam collimation.