Patient dose reference levels for interventional radiology: a national approach

A set of patient dose reference levels (RLs) for fluoroscopically guided interventional procedures was obtained in a survey launched by the National Society of Interventional Radiology (IR), involving 10 public hospitals, as recommended by the European Medical Exposures Directive. A sample of 1391 dose values (kerma area product [KAP]) was collected randomly during clinical procedures for seven of the most frequent procedures. Third quartiles of the KAP distributions were used to set the RLs. A regular quality control of the X-ray systems and a calibration of the dose meters were performed during the survey. The fluoroscopy time and total number of digital subtraction angiography images per procedure were also analyzed. The RL values proposed were 12 Gy cm(2) for fistulography (hemodialysis access; sample of 180 cases), 73 Gy cm(2) for lower limb arteriography (685 cases), 89 Gy cm(2) for renal arteriography (55 cases), 80 Gy cm(2) for biliary drainage (205 cases), 289 Gy cm(2) for hepatic chemoembolization (151 cases), 94 Gy cm(2) for iliac stent (70 cases), and 236 Gy cm(2) for uterine embolization (45 cases). The provisional national RL values are lower than those obtained in a similar survey carried out in the United States from 2002 to 2004. These new values could be used to improve the practice of centers consistently working with doses higher than the RLs. This national survey also had a positive impact, as it helped increase the awareness of the members of the National Society of IR on a topic as crucial as patient dose values and programs on radiation protection.