title: Evaluation of the use of automatic exposure control and automatic tube potential selection in low-dose cerebrospinal fluid shunt head CT.
abstract: BACKGROUND
  Cerebrospinal fluid shunts are primarily used for the treatment of hydrocephalus. Shunt complications may necessitate multiple non-contrast head CT scans resulting in potentially high levels of radiation dose starting at an early age. A new head CT protocol using automatic exposure control and automated tube potential selection has been implemented at our institution to reduce radiation exposure. The purpose of this study was to evaluate the reduction in radiation dose achieved by this protocol compared with a protocol with fixed parameters.
  
  
  METHODS
  A retrospective sample of 60 non-contrast head CT scans assessing for cerebrospinal fluid shunt malfunction was identified, 30 of which were performed with each protocol. The radiation doses of the two protocols were compared using the volume CT dose index and dose length product. The diagnostic acceptability and quality of each scan were evaluated by three independent readers.
  
  
  RESULTS
  The new protocol lowered the average volume CT dose index from 15.2 to 9.2 mGy representing a 39 % reduction (P < 0.01; 95 % CI 35-44 %) and lowered the dose length product from 259.5 to 151.2 mGy/cm representing a 42 % reduction (P < 0.01; 95 % CI 34-50 %). The new protocol produced diagnostically acceptable scans with comparable image quality to the fixed parameter protocol.
  
  
  CONCLUSIONS
  A pediatric shunt non-contrast head CT protocol using automatic exposure control and automated tube potential selection reduced patient radiation dose compared with a fixed parameter protocol while producing diagnostic images of comparable quality.
authors.affiliation: Mallinckrodt Institute of Radiology, Barnes Jewish Hospital, St. Louis, MO, USA.
authors.forename: Adam N
authors.initials: AN
authors.lastname: Wallace
authors.forename: Ross
authors.initials: R
authors.lastname: Vyhmeister
authors.forename: Swapnil
authors.initials: S
authors.lastname: Bagade
authors.forename: Arindam
authors.initials: A
authors.lastname: Chatterjee
authors.forename: Brandon
authors.initials: B
authors.lastname: Hicks
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Ramirez-Giraldo
authors.forename: Robert C
authors.initials: RC
authors.lastname: McKinstry
mesh_terms: D000293:Adolescent; D000328:Adult; D002557:Cerebrospinal Fluid Shunts; D002648:Child; D002675:Child, Preschool; D002985:Clinical Protocols; D004868:Equipment Failure; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging* / Q000628:therapy*; D007223:Infant; D008297:Male; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000517:prevention & control*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult