Radiation burden to paediatric patients due to micturating cystourethrography examinations in a Dutch children's hospital

Micturating cystourethrography (MCU) examinations of paediatric patients in a major Dutch children's hospital (JKZ) were evaluated to generate quantit ative information on effective dose (E). A standard examination involves th ree radiographs plus fluoroscopy. Observed total dose-area product (DAP) fo r 84 children increased, on average, with increasing age class from 0.2 to 2.2 Gy cm(2). In 11 cases, separate DAP per view was measured; enabling det ermination, per view, of organ (C-F) and effective (C-E) dose conversion fa ctors, ie. dose per unit of DAP. Monte Carlo simulation of photon transport in male and female mathematical phantoms was applied for newborn, 1 year, 5 year, 10 year and 15-year-old patients, and interpolated for other ages. C-E per view decreases with increasing age class, yielding about a factor o f 10 difference between the extremes of the range. Female values are usuall y some 20-30% above male ones. C-E for one of the views appeared to be repr esentative for the complete examination and was used to estimate total E fo r each patient. Averaged per age class, E remains approximately constant at 0.3-0.4 mSv, although a tendency to increase with increasing age exists, f or females in particular. Within an age class, individual patients may diff er in E by a factor of two up to six. Stomach, lower large intestine, bladd er wall, liver and ovaries receive relatively high doses. Compared with pub lished data and DAP measured in a few other Dutch hospitals, the radiation burden of MCU is low at the JKZ. This indicates a good degree of optimizati on with respect to radiation protection (e.g. modern equipment, increased t ube voltage, fast film-screen combination).