Implementation of a patient dose monitoring system in conventional digital X-ray imaging: initial experiences. 
The purpose was to report on the initial experience after implementation of a patient dose-monitoring system in conventional X-ray imaging.  A dose-monitoring system collected dose data relating to different radiographs (one projection) and studies (two or more projections).  Images were acquired on digital X-ray systems equipped with flat-panel detectors.  During period 1, examinations were performed in a routine fashion in 12,614 patients.  After period 1, technical modifications were performed and radiographers underwent training in radiation protection.  During period 2, examinations were performed in 14,514 patients, and the radiographers were advised to read dose data after each radiograph/study.  Dose data were compared by means of kerma area product (KAP, gray × centimetre squared) and entrance surface air kerma (ESAK, milligray).  During period 1, 13,955 radiographs and 8,466 studies were performed, and in period 2 16,090 radiographs and 10,389 studies.  In period 2, KAP values for radiographs were an average of 25 % lower and for studies 7 % lower, and ESAK values for radiographs were 24 % lower and for studies 5 % lower.  The reduction in KAP was significant in 8/13 radiographs and in 6/14 studies, and the reduction in ESAK was significant in 6/13 radiographs and 5/14 studies.  Implementation of a patient dose-monitoring system in conventional X-ray imaging allows easy data collection, supports dose reduction efforts, and may increase radiographers' dose awareness. •  A dose-monitoring system enables easy dose data collection in X-ray imaging. •  The system facilitates dose reduction efforts and may increase radiographers' radiation awareness. •  Mean kerma-area-product significantly declined in period 2 in 8/13 radiographs and 6/14 studies. •  In ESAK a significant decline was evident in 6/13 radiographs and 5/14 studies.