タケガミ, カズキ Graduate School of Health Sciences, Tokushima University|Yamaguchi University Hospital
ヤマダ, ケンジ Tokushima University Hospital
ミハラ, ヨシキ School of Health Sciences, Tokushima University
キモト, ナツミ Graduate School of Health Sciences, Tokushima University
東野, 恒作 Graduate School of Biomedical Sciences, Tokushima University|Tokushima University Hospital KAKEN研究者をさがす
山下, 一太 Graduate School of Biomedical Sciences, Tokushima University|Tokushima University Hospital 徳島大学 教育研究者総覧
林, 二三男 Graduate School of Biomedical Sciences, Tokushima University|Tokushima University Hospital
オカザキ, トオル Nagase-Landauer, Ltd.
ハシズメ, タクヤ Nagase-Landauer, Ltd.
コバヤシ, イクオ Nagase-Landauer, Ltd.
Entrance surface dose
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.
Radiological Physics and Technology
Copyright © Japanese Society of Radiological Technology and Japan Society of Medical Physics 2016
The final publication is available at Springer via http://dx.doi.org/10.1007/s12194-016-0366-1.
rpt_10_1_49.pdf 1.3 MB