Diagnostic Reference Levels : the Swiss situation

The aim of this work is to describe how diagnostic reference levels (DRLs) are being established and implemented in Switzerland. Several nationwide surveys are launched in order to determine the patient dose distributions for a number of CT and fluoroscopy examinations that will be used to set up the corresponding DRLs. Meanwile the european recommended DRLs are considered. When no European recommended DRLs are available, values based on average doses for 257 types of radiological examinations established during the 1998 nation-wide survey on the exposure of the Swiss population by diagnostic and interventional radiology are suggested for temporary use. These average doses were calculated using an appropriate dosimetric model for each radiological modality. For each type of examination a standard technique is defined and the dose is established based on the standard procedure and technical parameters. The DRLs are derived from the average doses using an appropriate multiplying factor to give a result comparable with that obtained with the 3rd-quartile method commonly used at the international level.