title: Entrance surface dose measurements using a small OSL dosimeter with a computed tomography scanner having 320 rows of detectors.
abstract: Entrance surface dose (ESD) measurements are important in X-ray computed tomography (CT) for examination, but in clinical settings it is difficult to measure ESDs because of a lack of suitable dosimeters. We focus on the capability of a small optically stimulated luminescence (OSL) dosimeter. The aim of this study is to propose a practical method for using an OSL dosimeter to measure the ESD when performing a CT examination. The small OSL dosimeter has an outer width of 10 mm; it is assumed that a partial dose may be measured because the slice thickness and helical pitch can be set to various values. To verify our method, we used a CT scanner having 320 rows of detectors and checked the consistencies of the ESDs measured using OSL dosimeters by comparing them with those measured using Gafchromic™ films. The films were calibrated using an ionization chamber on the basis of half-value layer estimation. On the other hand, the OSL dosimeter was appropriately calibrated using a practical calibration curve previously proposed by our group. The ESDs measured using the OSL dosimeters were in good agreement with the reference ESDs from the Gafchromic™ films. Using these data, we also estimated the uncertainty of ESDs measured with small OSL dosimeters. We concluded that a small OSL dosimeter can be considered suitable for measuring the ESD with an uncertainty of 30 % during CT examinations in which pitch factors below 1.000 are applied.
authors.affiliation: Graduate School of Health Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.|Yamaguchi University Hospital, 1-1-1, Minamikogushi, Ube, Yamaguchi, 755-8505, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Takegami
authors.affiliation: Graduate School of Biomedical Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan. hayashi.hiroaki@tokushima-u.ac.jp.
authors.forename: Hiroaki
authors.identifier: http://orcid.org/0000-0002-8836-5068
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Tokushima University Hospital, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamada
authors.affiliation: School of Health Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Mihara
authors.affiliation: Graduate School of Health Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Natsumi
authors.initials: N
authors.lastname: Kimoto
authors.affiliation: Graduate School of Biomedical Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kanazawa
authors.affiliation: Graduate School of Biomedical Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.|Tokushima University Hospital, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Higashino
authors.affiliation: Graduate School of Biomedical Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.|Tokushima University Hospital, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Kazuta
authors.initials: K
authors.lastname: Yamashita
authors.affiliation: Graduate School of Biomedical Sciences, Tokushima University, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.|Tokushima University Hospital, 3-18-5 Kuramoto-cho, Tokushima, Tokushima, 770-8503, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Hayashi
authors.affiliation: Nagase-Landauer, Ltd., C22-1 Suwa, Tsukuba, Ibaraki, 300-2686, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Okazaki
authors.affiliation: Nagase-Landauer, Ltd., C22-1 Suwa, Tsukuba, Ibaraki, 300-2686, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Hashizume
authors.affiliation: Nagase-Landauer, Ltd., C22-1 Suwa, Tsukuba, Ibaraki, 300-2686, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Kobayashi
mesh_terms: D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D000072232:Radiation Dosimeters; D015898:Tomography Scanners, X-Ray Computed; D014867:Water
chemical_list: D014867:Water
keywords: Computed tomography; Entrance surface dose; Gafchromic™ film; OSL dosimeter