Variables influencing radiation exposure during extracorporeal shock wave lithotripsy. Review of 298 treatments.

Retrospective review of 298 extracorporeal shock wave lithotripsy (ESWL) treatments was undertaken to determine the factors which influence radiation exposure during ESWL. Fluoroscopy time averaged 160 seconds (3-509), and the average number of spot films taken per patient was 26 (5-68). The average stone burden was 19.3 mm (3-64). Average calculated skin surface radiation exposure was 17.8 R per treatment. Radiation exposure increased with increasing stone burden and patient weight. Stones treated in the ureter resulted in a higher average patient radiation exposure than for renal stones (19 R vs 16 R), even though the average size of these ureteral stones (11.3 mm) was significantly less than the mean. However, type of anesthetic (general or regional) used was not a significant factor. Operator training, experience, and familiarity with radiation physics should significantly decrease the amount of imaging time and consequent patient radiation exposure during ESWL.