title: Patient-specific dose calculations for pediatric CT of the chest, abdomen and pelvis.
abstract: BACKGROUND
  Organ dose is essential for accurate estimates of patient dose from CT.
  
  
  OBJECTIVE
  To determine organ doses from a broad range of pediatric patients undergoing diagnostic chest-abdomen-pelvis CT and investigate how these relate to patient size.
  
  
  METHODS
  We used a previously validated Monte Carlo simulation model of a Philips Brilliance 64 multi-detector CT scanner (Philips Healthcare, Best, The Netherlands) to calculate organ doses for 40 pediatric patients (M:F = 21:19; range 0.6-17 years). Organ volumes and positions were determined from the images using standard segmentation techniques. Non-linear regression was performed to determine the relationship between volume CT dose index (CTDIvol)-normalized organ doses and abdominopelvic diameter. We then compared results with values obtained from independent studies.
  
  
  RESULTS
  We found that CTDIvol-normalized organ dose correlated strongly with exponentially decreasing abdominopelvic diameter (R(2) > 0.8 for most organs). A similar relationship was determined for effective dose when normalized by dose-length product (R(2) = 0.95). Our results agreed with previous studies within 12% using similar scan parameters (e.g., bowtie filter size, beam collimation); however results varied up to 25% when compared to studies using different bowtie filters.
  
  
  CONCLUSIONS
  Our study determined that organ doses can be estimated from measurements of patient size, namely body diameter, and CTDIvol prior to CT examination. This information provides an improved method for patient dose estimation.
authors.affiliation: Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA. susan.d.kost@vanderbilt.edu.|Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA. susan.d.kost@vanderbilt.edu.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Kost
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Fraser
authors.affiliation: Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.|Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Diana E
authors.initials: DE
authors.lastname: Carver
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Pickens
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Price
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Hernanz-Schulman
authors.affiliation: Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.|Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Stabin
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009010:Monte Carlo Method; D061330:Multidetector Computed Tomography / Q000706:statistics & numerical data*; D010388:Pelvis / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000706:statistics & numerical data*; D013902:Radiography, Thoracic / Q000706:statistics & numerical data*
keywords: Children; Computed tomography; Effective dose; Monte Carlo; Organ dose; Patient size