Effective doses to patients from paediatric cardiac catheterization

The Council Directive of the European Communities 97/43/Euratom requires do se assessment, especially for X-ray examinations of children and if high do ses to the patient are involved, Both these aspects apply in cardiac cathet erization and angiocardiography of children, Effective doses are a good ind icator of radiation risk, particularly for leukaemia. Effective doses have been determined for 2114 infants and children undergoing cardiac catheteriz ation from 1984 to 1996 at the University Hospital in Essen. Conversion fac tors (effective dose/dose-area product) were calculated based on direct dos e-area product measurements for posteroanterior (PA) and lateral (Lat) proj ections as well as on patient records and examination details. The factors are calculated for eight age groups of children, taking into account the X- ray tube voltage for fluoroscopy and cine-film sequences, with and without zoom mode. Frequency distributions are presented for 2114 patients, for dos e-area product, number of angiographic examinations (each combined with one cine-him sequence both PA and Lat) and for calculated effective doses. Hig hest effective doses are found in newborns (18.0 mSv and 6.5 mSv 90th and 5 0th percentiles, respectively) compared with adolescents of 15-21 years (18 .0 mSv and 3.0 mSv 90th and 50th percentiles, respectively). Effective dose for cardiac catheterization is highest for newborns, in spite of lowest me asured dose-area products, because the decreased value of the conversion fa ctors overcompensates for the increase of dose-area product with age. This is especially important because of the higher tumour risk for equal effecti ve dose for young children compared with adults.