Practical method for determination of air kerma by use of an ionization chamber toward construction of a secondary X-ray field to be used in clinical examination rooms

URI http://www.lib.tokushima-u.ac.jp/repository/metadata/110812
タイトル
Practical method for determination of air kerma by use of an ionization chamber toward construction of a secondary X-ray field to be used in clinical examination rooms
作成者
Maehata, Itsumi
Hayashi, Hiroaki
Kimoto, Natsumi
Takegami, Kazuki
Okino, Hiroki
Kanazawa, Yuki
Tominaga, Masahide
作成者ヨミ
マエハタ, イツミ
ハヤシ, ヒロアキ
キモト, ナツミ
タケガミ, カズキ
オキノ, ヒロキ
カナザワ, ユウキ
トミナガ, マサヒデ
作成者別表記
林, 裕晃
金澤, 裕樹
富永, 正英
作成者所属
School of Health Sciences, Tokushima University
Institute of Biomedical Sciences, Tokushima University Graduate School
Graduate School of Health Sciences, Tokushima University
キーワード
Ionization chamber
Air kerma
Contamination rate
Scattered X-rays
Diagnostic X-ray equipment
Secondary X-ray field
抄録

We propose a new practical method for the construction of an accurate secondary X-ray field using medical diagnostic X-ray equipment. For accurate measurement of the air kerma of an X-ray field, it is important to reduce and evaluate the contamination rate of scattered X-rays. To determine the rate quantitatively, we performed the following studies. First, we developed a shield box in which an ionization chamber could be set at an inner of the box to prevent detection of the X-rays scattered from the air. In addition, we made collimator plates which were placed near the X-ray source for estimation of the contamination rate by scattered X-rays from the movable diaphragm which is a component of the X-ray equipment. Then, we measured the exposure dose while changing the collimator plates, which had diameters of 25–90 mmϕ. The ideal value of the exposure dose was derived mathematically by extrapolation to 0 mmϕ. Tube voltages ranged from 40 to 130 kV. Under these irradiation conditions, we analyzed the contamination rate by the scattered X-rays. We found that the contamination rates were less than 1.7 and 2.3 %, caused by air and the movable diaphragm, respectively. The extrapolated value of the exposure dose has been determined to have an uncertainty of 0.7 %. The ionization chamber used in this study was calibrated with an accuracy of 5 %. Using this kind of ionization chamber, we can construct a secondary X-ray field with an uncertainty of 5 %.

出版者
Springer Japan
資料タイプ
学術雑誌論文
ISSN・ISBN
18650333
18650341
cat書誌id
AA12236881
掲載誌名
Radiological Physics and Technology
9
2
開始ページ
193
終了ページ
201
発行日
2016-03-18
備考

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/s12194-016-0352-7.

edb id
306432
出版社版URL
部局
徳島大学
ファイル
本文言語
eng
著者版フラグ
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