title: Perfusion CT of the Brain and Liver and of Lung Tumors: Use of Monte Carlo Simulation for Patient Dose Estimation for Examinations With a Cone-Beam 320-MDCT Scanner.
abstract: OBJECTIVE
  The purpose of this study was to estimate the patient dose from perfusion CT examinations of the brain, lung tumors, and the liver on a cone-beam 320-MDCT scanner using a Monte Carlo simulation and the recommendations of the International Commission on Radiological Protection (ICRP).
  
  
  METHODS
  A Monte Carlo simulation based on the Electron Gamma Shower Version 4 package code was used to calculate organ doses and the effective dose in the reference computational phantoms for an adult man and adult woman as published by the ICRP. Three perfusion CT acquisition protocols--brain, lung tumor, and liver perfusion--were evaluated. Additionally, dose assessments were performed for the skin and for the eye lens. Conversion factors were obtained to estimate effective doses and organ doses from the volume CT dose index and dose-length product.
  
  
  RESULTS
  The sex-averaged effective doses were approximately 4 mSv for perfusion CT of the brain and were between 23 and 26 mSv for the perfusion CT body protocols. The eye lens dose from the brain perfusion CT examination was approximately 153 mGy. The sex-averaged peak entrance skin dose (ESD) was 255 mGy for the brain perfusion CT studies, 157 mGy for the lung tumor perfusion CT studies, and 172 mGy for the liver perfusion CT studies.
  
  
  CONCLUSIONS
  The perfusion CT protocols for imaging the brain, lung tumors, and the liver performed on a 320-MDCT scanner yielded patient doses that are safely below the threshold doses for deterministic effects. The eye lens dose, peak ESD, and effective doses can be estimated for other clinical perfusion CT examinations from the conversion factors that were derived in this study.
authors.affiliation: 1 Medical Physics Unit, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, C/Sant Llorenç 21, 43201 Reus, Tarragona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Cros
authors.affiliation: 2 Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jacob
authors.initials: J
authors.lastname: Geleijns
authors.affiliation: 2 Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Raoul M S
authors.initials: RM
authors.lastname: Joemai
authors.affiliation: 1 Medical Physics Unit, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili, C/Sant Llorenç 21, 43201 Reus, Tarragona, Spain.
authors.forename: Marçal
authors.initials: M
authors.lastname: Salvadó
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: International Commission on Radiological Protection (ICRP) computational phantoms; Monte Carlo simulation; cone-beam 320-MDCT scanner; patient dose assessment; perfusion CT