A Nordic survey of patient doses in diagnostic radiology

The aim of this study was to test the applicability of the guidance levels for patient doses cooperatively set by the radiation protection authorities in the five Nordic countries. The kerma-area product (KAP) for five conventional radiological examination types was obtained from several hospitals in each of the Nordic countries. The number of radiographic images and fluoroscopy time were also registered, and the mean values for each examination type and hospital were established based on a representative number of patients (40-100 kg). The results indicate that the situation is very similar in the five Nordic countries, even though some differences were identified. Most of the hospitals demonstrated lower doses than the proposed guidance levels for chest, probably explained by use of faster film/screen combinations during the past decade. An increased use of fluoroscopy for positioning was observed for radiographic examinations of lumbar spine and urography. Large variations in patient doses were found for barium enema depending on the use of fluorospot or 100-mm camera vs full-format film, the range in fluoroscopy times, dose rate, and field size. The guidance levels for lumbar spine (10 Gy x cm2), pelvis (4 Gy x cm2), urography (20 Gy x cm2), and barium enema (50 Gy x cm2) seem to reflect the present quality of X-ray equipment and examination techniques in the Nordic countries. The guidance levels for chest (1 Gy x cm2) should be lowered to 0.6 Gy x cm2.