title: Survey of volume CT dose index in Japan in 2014.
abstract: OBJECTIVE
  The aims of this study are to propose a new set of Japanese diagnostic reference levels (DRLs) for 2014 and to study the impact of tube voltage and the type of reconstruction algorithm on patient doses. The volume CT dose index (CTDI(vol)) for adult and paediatric patients is assessed and compared with the results of a 2011 national survey and data from other countries.
  
  
  METHODS
  Scanning procedures for the head (non-helical and helical), chest and upper abdomen were examined for adults and 5-year-old children. A questionnaire concerning the following items was sent to 3000 facilities: tube voltage, use of reconstruction algorithms and displayed CTDI(vol).
  
  
  RESULTS
  The mean CTDI(vol) values for paediatric examinations using voltages ranging from 80 to 100 kV were significantly lower than those for paediatric examinations using 120 kV. For adult examinations, the use of iterative reconstruction algorithms significantly reduced the mean CTDI(vol) values compared with the use of filtered back projection. Paediatric chest and abdominal scans showed slightly higher mean CTDI(vol) values in 2014 than in 2011. The proposed DRLs for adult head and abdominal scans were higher than those reported in other countries.
  
  
  CONCLUSIONS
  The results imply that further optimization of CT examination protocols is required for adult head and abdominal scans as well as paediatric chest and abdominal scans.
  
  
  CONCLUSIONS
  Low-tube-voltage CT may be useful for reducing radiation doses in paediatric patients. The mean CTDI(vol) values for paediatric scans showed little difference that could be attributed to the choice of reconstruction algorithm.
authors.affiliation: 1 Department of Imaging, Nagoya Kyoritsu Hospital, Nagoya, Aichi, Japan.|2 Graduate school of Medicine, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsunaga
authors.affiliation: 2 Graduate school of Medicine, Tohoku University, Sendai, Miyagi, Japan.|3 Department of Radiology, Toyota Memorial Hospital, Toyota, Aichi, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kawaguchi
authors.affiliation: 4 Department of Radiology, Fujita Health University Hospital, Toyoake, Aichi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: 4 Department of Radiology, Fujita Health University Hospital, Toyoake, Aichi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kinomura
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Aichi, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: 4 Department of Radiology, Fujita Health University Hospital, Toyoake, Aichi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Asada
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Aichi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Minami
authors.affiliation: 5 School of Health Sciences, Fujita Health University, Toyoake, Aichi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: 2 Graduate school of Medicine, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Chida
mesh_terms: D000328:Adult; D002675:Child, Preschool; D054893:Cone-Beam Computed Tomography / Q000592:standards*; D006801:Humans; D007564:Japan; D011829:Radiation Dosage; D012016:Reference Values; D011795:Surveys and Questionnaires