Development of diagnostic reference levels in paediatric radiology

With a very wide range in patient size from a newborn baby to a 15 year old adolescent, reference doses for paediatric radiology can sensibly be established only for specific sizes of children. Five standard sizes have been chosen representing newborn, 1, 5, 10 and 15 years. A method is described for normalising the dose measured on a child of any size and age to the corresponding dose to the nearest standard sized patient. Normalisation factors for entrance surface dose and dose-area product measurements were calculated based on effective linear attenuation coefficients (μ) measured in phantoms and calculated by Monte Carlo techniques for the typical x-ray spectra and field sizes used in paediatric radiology. These normalisation factors were applied to European paediatric dose survey data to derive some preliminary size/age specific reference doses for some common radiographic projections and for micturating cystourethrography (MCU), the most common fluoroscopic examination performed on children. (author)