title: Relationships of pediatric anthropometrics for CT protocol selection.
abstract: OBJECTIVE
  Determining the optimal CT technique to minimize patient radiation exposure while maintaining diagnostic utility requires patient-specific protocols that are based on patient characteristics. This work develops relationships between different anthropometrics and CT image noise to determine appropriate protocol classification schemes.
  
  
  METHODS
  We measured the image noise in 387 CT examinations of pediatric patients (222 boys, 165 girls) of the chest, abdomen, and pelvis and generated mathematic relationships between image noise and patient lateral and anteroposterior dimensions, age, and weight.
  
  
  RESULTS
  At the chest level, lateral distance (ld) across the body is strongly correlated with weight (ld = 0.23 × weight + 16.77; R(2) = 0.93) and is less well correlated with age (ld = 1.10 × age + 17.13; R(2) = 0.84). Similar trends were found for anteroposterior dimensions and at the abdomen level. Across all studies, when acquisition-specific parameters are factored out of the noise, the log of image noise was highly correlated with lateral distance (R(2) = 0.72) and weight (R(2) = 0.72) and was less correlated with age (R(2) = 0.62). Following first-order relationships of image noise and scanner technique, plots were formed to show techniques that could achieve matched noise across the pediatric population.
  
  
  CONCLUSIONS
  Patient lateral distance and weight are essentially equally effective metrics to base maximum technique settings for pediatric patient-specific protocols. These metrics can also be used to help categorize appropriate reference levels for CT technique and size-specific dose estimates across the pediatric population.
authors.affiliation: 1 Department of Radiology, Seattle Children's Hospital, Seattle, WA.
authors.forename: Grace S
authors.initials: GS
authors.lastname: Phillips
authors.forename: Arta-Luana
authors.initials: AL
authors.lastname: Stanescu
authors.forename: Adam M
authors.initials: AM
authors.lastname: Alessio
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008962:Models, Theoretical; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: CT protocols; anthropometry CT acquisition; pediatric CT; pediatrics; radiation dose; size-specific dose estimation (SSDE)