Automated pediatric abdominal effective diameter measurements versus age-predicted body size for normalization of CT dose

J Digit Imaging. 2013 Dec;26(6):1151-5. doi: 10.1007/s10278-013-9623-6.


There has been increasing interest in adjusting CT radiation dose data for patient body size. A method for automated computation of the abdominal effective diameter of a patient from a CT image has previously only been tested in adult patients. In this work, we tested the method on a set of 128 pediatric patients aged 0.8 to 12.9 years (average 8.0 years, SD = 3.7 years) who had CT abdomen/pelvis exams performed on a Toshiba Aquilion 64 scanner. For this set of patients, age-predicted abdominal effective diameter extrapolated based on data from the International Commission on Radiation Units and Measurements was a relatively poor predictor of measured effective diameter. The mean absolute percentage error between the CTDI normalization coefficient calculated from a manually measured effective diameter and the coefficient determined by age-predicted effective diameter was 12.3 % with respect to a 32 cm phantom (range 0.0-52.8 %, SD 8.7 %) and 12.9 % with respect to a 16 cm phantom (range 0.0-56.4 %, SD 9.2 %). In contrast, there is a close correspondence between the automated and manually measured patient effective diameters, with a mean absolute error of 0.6 cm (error range 0.2-1.3 cm). This correspondence translates into a high degree of correspondence between normalization coefficients determined by automated and manual measurements; the mean absolute percentage error was 2.1 % with respect to a 32 cm phantom (range 0.0-8.1 %, SD = 1.4 %) and 2.3 % with respect to a 16 cm phantom (range 0.0-9.3 %, SD = 1.6 %).

MeSH terms

  • Age Factors
  • Automation
  • Body Size / radiation effects*
  • Child
  • Child, Preschool
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Monte Carlo Method
  • Pediatrics
  • Pelvis / diagnostic imaging
  • Phantoms, Imaging*
  • Predictive Value of Tests
  • Radiation Dosage
  • Radiation Monitoring / methods
  • Radiography, Abdominal / methods*
  • Reference Values
  • Retrospective Studies
  • Risk Assessment
  • Tomography, X-Ray Computed / adverse effects
  • Tomography, X-Ray Computed / methods*