[Multislice spiral CT (MSCT) in pediatric radiology: dose reduction for chest and abdomen examinations]

The advent of multislice spiral CT (MSCT) technique has led to new aspects of dose reduction, especially for the dedicated use of MSCT in children. Optimizing pediatric MSCT protocols according to the clinical problem allows reduction of radiation exposure to a minimum without loss of diagnostic quality. The different parameters that influence the degree of dose reduction, like tube current-time product (mAs), tube voltage (kV), collimation and pitch, are discussed in context with previously published data and our own experience in nearly 200 pediatric CT examinations. In our department, the effective mAs is calculated for a pediatric chest MSCT by multiplication of the body weight in kilogram with a factor of 1 to 1.5 and for a pediatric abdominal MSCT by multiplication with a factor of 2 to 2.5. To calculate the equivalent effective dose for a contrast media-enhanced 80 kV protocol, the effective mAs of the 120 kV protocol can be multiplied by 2.7. A factor less than 2.7 means further dose reduction. Compared to the radiation exposure with a standard adult protocol, the effective dose in a pediatric thoracic MSCT could be reduced by up to 92 % in neonates, 89 % in toddlers and 80 % in school children. In abdominal MSCT, the effective dose could be reduced by up to 90 % in neonates, 89 % in toddlers and 83 % in school children. Using an adequate MSCT technique in children by adjusting the CT scanning parameters to the clinical question and body weight of the examined child enables a significant reduction of radiation exposure in comparison to standard MSCT protocols.