title: Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children.
abstract: BACKGROUND
  It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children.
  
  
  OBJECTIVE
  To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children.
  
  
  METHODS
  Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates.
  
  
  RESULTS
  Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans.
  
  
  CONCLUSIONS
  Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children.
authors: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, Korea.
authors: Eunsol
authors: E
authors: Lee
authors: Hyun Woo
authors: HW
authors: Goo
authors: Jae-Yeong
authors: JY
authors: Lee
mesh_terms: D065638:Absorption, Radiation; D000293:Adolescent; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D009928:Organ Specificity; D011829:Radiation Dosage; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D017678:Sex Distribution; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014915:Whole-Body Counting / Q000706:statistics & numerical data*