title: Image quality and radiation exposure in 320-row temporal bone computed tomography.
abstract: OBJECTIVE
  The aim was to define image quality and radiation exposure in the recently introduced 320-row CT of the temporal bone (tb) in comparison to a 16-row tb CT.
  
  
  METHODS
  A cadaveric head phantom was used for repeated tb volume CT studies (80-120 kV, 25-150 mAs), performed in a 320-row scanner (single rotation, 0.5 mm slice thickness, kernel FC 51) in comparison to 16-row helical CT using standard acquisition parameters (SAP) of 120 kV and 75 mAs (kernel FC 53). Qualitative image evaluation was performed by two radiologists using a 5-point visual analogue scale. Image noise (D(SD)) was determined by region of interest (ROI) based measurements in cadaveric as well as water phantom studies. Dosimetric measurements of the effective dose (ED) and organ dose (OD) of the lens were performed.
  
  
  RESULTS
  Image quality of 320-row tb CT was equivalent to 16-row CT for SAP scans, resulting in image noise levels (D(SD) 16-/320-row) of 109/237 and 206/446 for air and bone respectively. D(SD) differences were predominantly (>90%) attributable to the different kernels available for tb studies in 16- and 320-row CT. Radiation exposure for 16-/320-row SAP scans amounted to 0.36/0.30 mSv (ED) and 10.0/8.4 mGy (lens dose).
  
  
  CONCLUSIONS
  320-row volume acquisition in tb CT delivers equivalent image quality to 16-row CT while decreasing radiation exposure figures by one sixth. Image noise increase in 320-row CT is negligible with respect to image quality.
authors.affiliation: Department of Neuroradiology, Chariteplatz 1, Berlin, Germany. christian.bauknecht@charite.de
authors.forename: H C
authors.initials: HC
authors.lastname: Bauknecht
authors.forename: E
authors.initials: E
authors.lastname: Siebert
authors.forename: A
authors.initials: A
authors.lastname: Dannenberg
authors.forename: G
authors.initials: G
authors.lastname: Bohner
authors.forename: C
authors.initials: C
authors.lastname: Jach
authors.forename: S
authors.initials: S
authors.lastname: Diekmann
authors.forename: C
authors.initials: C
authors.lastname: Scheurig
authors.forename: R
authors.initials: R
authors.lastname: Klingebiel
mesh_terms: D016477:Artifacts; D002102:Cadaver; D004424:Ear Canal / Q000000981:diagnostic imaging; D004429:Ear Ossicles / Q000000981:diagnostic imaging; D007758:Ear, Inner / Q000000981:diagnostic imaging; D004432:Ear, Middle / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008416:Mastoid / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D011873:Radiology Information Systems; D013701:Temporal Bone / Q000000981:diagnostic imaging* / Q000528:radiation effects; D036542:Tomography, Spiral Computed / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*
references.citation: Acad Radiol. 2006 Jul;13(7):893-908
references.pmid: 16777564
references.citation: Eur Radiol. 2006 Sep;16(9):2100-8
references.pmid: 16568264
references.citation: Med Phys. 2006 Sep;33(9):3359-68
references.pmid: 17022232
references.citation: Radiographics. 2006 Oct;26 Suppl 1:S117-32
references.pmid: 17050510
references.citation: Med Phys. 2005 Jun;32(6):1621-9
references.pmid: 16013721
references.citation: Radiology. 1980 Feb;134(2):409-14
references.pmid: 7352220
references.citation: Br J Radiol. 2003 Jun;76(906):418-20
references.pmid: 12814929
references.citation: Eur J Radiol. 2008 Mar;65(3):442-8
references.pmid: 17628377
references.citation: Eur Radiol. 2005 Dec;15 Suppl 5:E35-45
references.pmid: 18637229
references.citation: Acta Otolaryngol. 2001 Jul;121(5):632-6
references.pmid: 11583399
references.citation: Eur Radiol. 2003 Dec;13 Suppl 5:M3-13
references.pmid: 14989605
references.citation: Invest Radiol. 2006 Nov;41(11):781-92
references.pmid: 17035868
references.citation: Eur Radiol. 2007 Oct;17(10):2638-45
references.pmid: 17342488
references.citation: Ann ICRP. 2007;37(1):1-79, iii
references.pmid: 18069128
references.citation: Acad Radiol. 2006 Jun;13(6):701-12
references.pmid: 16679272
references.citation: AJR Am J Roentgenol. 1993 Mar;160(3):479-81
references.pmid: 8430539
references.citation: Med Phys. 1999 Jan;26(1):5-18
references.pmid: 9949393