Application of European Commission reference dose levels in CT examinations in Crete, Greece

The purpose of this study was to apply European Commission reference dose levels (EC RDLs) to routine CT examinations. The dosimetric quantities proposed in the European Guidelines (EG) for CT are weighted computed tomography dose index (CTDI(w)) for a single slice and dose-length product (DLP) for a complete examination. Patient-related data as well as technical parameters for brain, chest, abdomen and pelvis examinations were collected for four CT scanners in the Euromedica Medical Center. Computed tomography dose index (CTDI) measurements were performed on each scanner and CTDI(w), DLP and effective dose E were estimated for each type of examination for a random sample of 10 typical patients. Mean values of CTDI(w) had a range of 27.0-52.0 mGy for brain and 13.9-26.9 mGy for chest, abdomen and pelvis examinations. Mean values of DLP had a range of 430-758 mGy cm for brain, 348-807 mGy cm for chest, 278-582 mGy cm for abdomen and 306-592 mGy cm for pelvis examinations. Mean values of E were 1.4 mSv for brain, 10.9 mSv for chest, 7.1 mSv for abdomen and 9.3 mSv for pelvis examinations. Results confirm that the Euromedica Medical Center meets EC RDLs for brain, abdomen and pelvis examinations, in terms of radiation dose and examination technique. As far as chest examination is concerned, although CTDI(w) of each scanner is within proposed values, the DLP is consistently exceeded, probably because of the large irradiation volume length L. It is anticipated that a reduction of L, or product mAs, or their combination, will reduce DLP without affecting image quality.