title: Effective radiation doses of CT examinations in Japan: a nationwide questionnaire-based study.
abstract: OBJECTIVE
  The aims of this study were to estimate the effective radiation doses from CT examinations of both adults and children in Japan and to study the impact of various scan parameters on the effective doses.
  
  
  METHODS
  A questionnaire, which contained detailed questions on the CT scan parameters employed, was distributed to 3000 facilities throughout Japan. For each scanner protocol, the effective doses for head (non-helical and helical), chest and upper abdomen acquisitions were estimated using ImPACT CT Patient Dosimetry Calculator software v. 1.0.4 (St George's Hospital, London, UK).
  
  
  RESULTS
  The mean effective doses for chest and abdominal examinations using 80-110 kV were significantly lower than those using 120 kV. However, there was no statistically significant difference in the mean effective doses for head scans between facilities employing 80-110 kV and 120 kV. In chest and abdominal examinations, the mean effective doses using CT scanners from Western manufacturers [Siemens (Forchheim, Germany), Philips (Eindhoven, Netherlands) and GE Medical Systems (Milwaukee, WI)] were significantly lower than those of examinations using Japanese scanners [Hitachi (Kashiwa, Japan) and Toshiba (Otawara, Tochigi, Japan)], except for in paediatric chest examinations.
  
  
  CONCLUSIONS
  The mean effective doses for adult head, chest and abdominal CT examinations were 2.9, 7.7 and 10.0 mSv, respectively, whereas the corresponding mean effective doses for paediatric examinations were 2.6, 7.1 and 7.7 mSv, respectively.
  
  
  CONCLUSIONS
  Facilities using CT scanners by Western manufacturers commonly adopt low-tube-voltage techniques, and low-tube-voltage CT may be useful for reducing the radiation doses to the patients, particularly for the body region.
authors.affiliation: 1 Department of Imaging, Nagoya Kyoritsu Hospital, Nagoya, Japan.|2 Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Matsunaga
authors.affiliation: 2 Graduate School of Medicine, Tohoku University, Sendai, Japan.|3 Department of Radiology, Toyota Memorial Hospital, Toyota, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Kawaguchi
authors.affiliation: 4 Department of Radiology, Fujita Health University Hospital, Toyoake, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Masanao
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Asada
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Minami
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: 2 Graduate School of Medicine, Tohoku University, Sendai, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Chida
mesh_terms: D000328:Adult; D002648:Child; D006801:Humans; D007564:Japan; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed / Q000379:methods*