title: Use of 100 kV versus 120 kV in computed tomography pulmonary angiography in the detection of pulmonary embolism: effect on radiation dose and image quality.
abstract: OBJECTIVE
  To determine the effective radiation dose and image quality resulting from 100 versus 120 kilovoltage (kV) protocols among patients referred for computed tomography pulmonary angiography (CTPA).
  
  
  METHODS
  Sixty-six patients with clinical suspicion of pulmonary embolism (PE) were prospectively enrolled. Two CTPA protocols (group A: n=33, 100 kV/115 mAs; group B: n=33, 120 kV/90 mAs) were compared. Two experienced radiologists assessed image quality in terms of diagnostic performance and effect of artefacts. Image quality parameters [CT attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)] and effective radiation dose between the two protocols were compared.
  
  
  RESULTS
  The contrast enhancement in central and peripheral pulmonary arteries was significantly higher in group A than in group B (P<0.001) with the identical SNR (P=0.26), whereas the CNR was significantly higher in group A than in group B (P<0.001). The effective radiation dose for the 100 and 120 kV scans was 3.2 and 6.8 mSv, respectively.
  
  
  CONCLUSIONS
  Reducing the tube voltage from 120 to 100 kV in CTPA allows a significant reduction of radiation dose without significant loss of diagnostic image quality.
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Maninderpal Kaur
authors.initials: MK
authors.lastname: Gill
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Anushya
authors.initials: A
authors.lastname: Vijayananthan
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Gnana
authors.initials: G
authors.lastname: Kumar
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Kasthoori
authors.initials: K
authors.lastname: Jayarani
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Kwan-Hoong
authors.initials: KH
authors.lastname: Ng
authors.affiliation: 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia ; 2 University of Malaya Research Imaging Centre (UMRIC), University of Malaya, Kuala Lumpur, Malaysia ; 3 Department of Medical Radiation Sciences, Faculty of Science and Engineering, Curtin University, Perth, Western Australia, Australia.
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Sun
keywords: Computed tomography pulmonary angiography (CTPA); image quality; pulmonary embolism (PE); radiation dose