title: Radiation dose evaluation in 64-slice CT examinations with adult and paediatric anthropomorphic phantoms.
abstract: The objective of this study was to evaluate the organ dose and effective dose to patients undergoing routine adult and paediatric CT examinations with 64-slice CT scanners and to compare the doses with those from 4-, 8- and 16-multislice CT scanners. Patient doses were measured with small (<7 mm wide) silicon photodiode dosemeters (34 in total), which were implanted at various tissue and organ positions within adult and 6-year-old child anthropomorphic phantoms. Output signals from photodiode dosemeters were read on a personal computer, from which organ and effective doses were computed. For the adult phantom, organ doses (for organs within the scan range) and effective doses were 8-35 mGy and 7-18 mSv, respectively, for chest CT, and 12-33 mGy and 10-21 mSv, respectively, for abdominopelvic CT. For the paediatric phantom, organ and effective doses were 4-17 mGy and 3-7 mSv, respectively, for chest CT, and 5-14 mGy and 3-9 mSv, respectively, for abdominopelvic CT. Doses to organs at the boundaries of the scan length were higher for 64-slice CT scanners using large beam widths and/or a large pitch because of the larger extent of over-ranging. The CT dose index (CTDI(vol)), dose-length product (DLP) and the effective dose values using 64-slice CT for the adult and paediatric phantoms were the same as those obtained using 4-, 8- and 16-slice CT. Conversion factors of DLP to the effective dose by International Commission on Radiological Protection 103 were 0.024 mSvmGy(-1)cm(-1) and 0.019 mSvmGy(-1)cm(-1) for adult chest and abdominopelvic CT scans, respectively.
authors.affiliation: National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba, Japan. j070205d@mbox.nagoya-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Fujii
authors.forename: T
authors.initials: T
authors.lastname: Aoyama
authors.forename: C
authors.initials: C
authors.lastname: Yamauchi-Kawaura
authors.forename: S
authors.initials: S
authors.lastname: Koyama
authors.forename: M
authors.initials: M
authors.lastname: Yamauchi
authors.forename: S
authors.initials: S
authors.lastname: Ko
authors.forename: K
authors.initials: K
authors.lastname: Akahane
authors.forename: K
authors.initials: K
authors.lastname: Nishizawa
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D010388:Pelvis / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000379:methods; D013902:Radiography, Thoracic / Q000379:methods; D011874:Radiometry / Q000379:methods; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000379:methods*