title: Effective DQE (eDQE) and dose to optimize radiographic technical parameters: a survey of pediatric chest X-ray examinations in Korea.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect of various technical parameters for dose optimization in pediatric chest radiological examinations by evaluating effective dose and effective detective quantum efficiency (eDQE).
  
  
  METHODS
  For tube voltages ranging from 40 to 90 kV in 10 kV increments at the focus-to-detector distance (FDD) of 100, 110, 120, 150, 180 cm, the eDQE was evaluated at same effective dose.
  
  
  RESULTS
  The eDQE was considerably higher without the use of the grid on equivalent effective dose. This indicates that the reduction of scatter radiation did not compensate for the loss of absorbed effective photons in the grid. The eDQE increased with increasing FDD because of the greater effective modulation transfer function (eMTF) with lower focal spot blurring. However, most of the major hospitals in Korea employed a short FDD of 100 cm with the grid. The entrance surface air kerma values for the hospitals of this survey exceeded the Korean reference level of 100 μGy.
  
  
  CONCLUSIONS
  The different reference levels might be appropriate for the same examination conducted on children of different ages. Also, it is necessary to refine the technical parameters to perform pediatric chest examinations.
authors: Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju, 220-710, Korea, radiosugar@yosnei.ac.kr.
authors: Hye-Suk
authors: HS
authors: Park
authors: Ye-Seul
authors: YS
authors: Kim
authors: Ok-Seob
authors: OS
authors: Park
authors: Sang-Tae
authors: ST
authors: Kim
authors: Chang-Woo
authors: CW
authors: Jeon
authors: Hee-Joung
authors: HJ
authors: Kim
mesh_terms: D002648:Child; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D013902:Radiography, Thoracic / Q000592:standards*; D056910:Republic of Korea; D012542:Scattering, Radiation