Dose Optimization and Reduction in CT of Children

Abstract

Children differ from adult patients in that they vary tremendously in their small size—which mandates adaptation of physical scan parameters—but also in their elevated susceptibility to ionizing radiation, and the different pathology during childhood. While the many technical innovations in CT during the last decade have impacted the entire field of clinical applications, faster scanning in children often makes the difference by eliminating motion artifacts; a number of new features contribute to reducing radiation exposure of children, most importantly iterative reconstruction and adaptive dose shielding. Limited cooperation of children often influences image quality more significantly than the choice of scanning parameters. Decreasing anxiety, avoiding pain, exercising cooperation before the scan, and avoiding artifacts by eliminating foreign bodies from the scan field are measures of high importance; a child-friendly atmosphere and staff further contribute to a successful scan. Choosing appropriate pediatric protocols means using each feature of a specific scanner to the best of the individual child, often accepting noise, scanning the minimal length and avoiding repeat/multiphase scans of the same volume. It is suggested to start with a scanner-optimized adult abdominal or head scan protocol and to reduce mAs according to tables available in the internet. In addition, lowering tube voltage is an excellent tool for high-contrast organs and CT angiography in children. Radiation risks based on biology and physics have been covered in previous chapters and are, of course, also valid for children. Similarly, clinical approaches to dose optimization and reduction are similar in pediatric and adult CT examinations (Huda et al., Pediatr Radiol 32:272–279, 2000). This chapter will concentrate on the fact that children are not just adults with smaller dimensions, thus it will point out what is special in children.