Proposed Procedure for the Establishment of Diagnostic Reference Levels in Germany

In Germany, an expert group of physicians and medical physicists was installed under the leadership of the Federal Office for Radiation Protection for the establishment and application of reference dose levels for patients involved in X ray diagnostic and diagnostic nuclear medicine applications. Up to now the following results have been obtained. (1) Reference levels should be established for frequent and for dose intensive examinations and should have an educational effect on physicians and radiographers concerning the optimisation of radiation protection. (2) They should apply to an easily measured quantity, which is available for the medical staff during the examination. (3) Dose measurements performed on standard patients or on a large number of non-selected patients and in line with the Guidelines of the German Federal Medical Board will be the basis for radiographic reference levels. Phantom measurements should be done in mammography and computed tomography (CT). (4) As different measured quantities are required for different types of examinations, the entrance surface dose (ESD) or the dose-area product (DAP) are proposed for radiography, the DAP for complex examinations including fluoroscopy, the entrance surface air kerma (ESAK) at the standard breast phantom for mammography and finally the weighted computed tomography dose index (CTDIw) and the dose length product (DLP) for CT examinations. Details referring to the collection of data and to the control of reference dose values are reported. (author)