SURVEY OF CT TECHNIQUES AND ABSORBED DOSE IN VARIOUS DUTCH HOSPITALS

The purpose of this study was to make an inventory of the radiation do se from CT in the Netherlands and to relate the dose to the way the ex amination was performed. Details were obtained from approximately 3000 CT examinations carried out in 18 hospitals (22 CT scanners). Effecti ve dose was calculated for each examination using CTDI-to-effective do se conversion factors. For most scanners, the conversion factors were available from the literature, for some they had to be derived with a computer model using a Monte Carlo algorithm. The data on effective do se, examination parameters and patient population are presented on a p er hospital basis. Mean effective doses from brain CT were 0.8-5 mSv, from lumbar spine CT 2-12 mSv, from chest CT 6-18 mSv and from abdomin al CT 6-24 mSv. The general indications for the various CT examination s were as follows: for the brain ischaemia and malignancy, for the lum bar spine disc herniation and for the chest and abdomen a known malign ancy. This explains the relatively advanced age of the patients. In ma ny hospitals intravenous contrast is used less than is recommended in current literature.