A stradegy for introducing diagnistic reference levels taking into account the national practice

Diagnostic reference levels (DRLs) are difficult to define in the case of X-ray examinations involving fluoroscopy particularly those performed in angiography and interventional radiology due to the large variability between examinations: fluoroscopy duration, number of images, image quality required. In order to tackle this problem a nation-wide dosimetric survey was performed in Switzerland involving five university hospitals, aiming at establishing a set of DRLs for eight types of examinations performed in diagnostic and interventional radiology. Each centre was requested to provide information on the patients and the technical data related to 20 examinations for each type. From the data collected, the distributions of the dose-area product, the number of images and the duration of fluoroscopy were established. A large variability of the technique was found. A set of DRL values was then determined using the 3rd-quartile method. These results will be sent to the radiologists to be analysed accompanied with some proposals for dose reduction.