Curriculum Vitaes
Profile Information
- Affiliation
- Professor, School of Health Sciences Department of Medical Sciences Education, Fujita Health University
- Degree
- 博士(医学)
- J-GLOBAL ID
- 200901036417982267
- researchmap Member ID
- 1000226782
Research Areas
1Papers
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Radiation Protection Dosimetry, 198(6) 339-348, Apr 27, 2022Abstract During fetal computed tomography (CT) imaging, because of differences in the pregnancy period and scanning conditions, different doses of radiation are absorbed by the fetus. We propose a correction coefficient for determining the fetal size-specific dose estimate (SSDE) from the CT dose index (CTDI) displayed on the console at tube voltages of 80–135 kVp. The CTDIs corresponding to pregnant women and fetuses were evaluated using a Monte Carlo (MC) simulation, and the ratio of these CTDIs was defined as the Fetus-factor. When the effective diameter of a fetus was approximately 10 cm, the Fetus-factor was 1.0. The estimated pregnant SSDE was multiplied by the Fetus-factor to estimate the fetal SSDE, which was compared with the fetal dose obtained by the MC simulation of the image of the fetal CT examination. The fetal dose could be estimated with an error of 31.5% in fetal examinations conducted using helical CT.
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Physical and Engineering Sciences in Medicine, Sep 14, 2020<title>Abstract</title> Organ-effective modulation (OEM) is a computed tomography scanning technique that reduces the exposure dose to organs at risk. Ultrasonography is commonly used for prenatal imaging, but its reliability is reported to be limited. Radiography and computed tomography (CT) are reliable but pose risk of radiation exposure to the pregnant woman and her fetus. Although there are many reports on the exposure dose associated with fetal CT scans, no reports exist on OEM use in fetal CT scans. We measured the basic characteristics of organ-effective modulation (X-ray output modulation angle, maximum X-ray output modulation rate, total X-ray output modulation rate, and noise modulation) and used them in a Monte Carlo simulation to evaluate the effect of this technique on fetal CT scans in terms of image quality and exposure dose to the pregnant woman and fetus. Using ImPACT MC software, Monte Carlo simulations of OEMON and OEMOFF were run on 8 cases involving fetal CT scans. We confirmed that the organ-effective modulation X-ray output modulation angle was 160°; the X-ray output modulation rate increased with increasing tube current; and no modulation occurred at tube currents of 80 mA or below. Our findings suggest that OEM has only a minimal effect in reducing organ exposure in pregnant women; therefore, it should be used on the anterior side (OEMON,front) to reduce the exposure dose to the fetus.
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Radiation Protection Dosimetry, 188(2) 261-269, Jun 13, 2020 Peer-reviewed<title>Abstract</title> The aim of this study was to investigate differences in volume computed tomography dose index (CTDIvol) and dose-length product (DLP) values according to facility size in Japan. A questionnaire survey was sent to 3000 facilities throughout Japan. Data from each facility were collected including bed number, computed tomography (CT) scan parameters employed and the CTDIvol and/or DLP values displayed on the CT scanner during each examination. The CTDIvol and DLP for 11 adult and 6 paediatric CT examinations were surveyed. Comparison of CTDIvol and DLP values of each examination according to facility size revealed key differences in CT dose between small and large facilities. This study highlights the importance of lowering the dose of coronary artery examination with contrast agent in smaller facilities and of lowering the dose of adult and paediatric head CT without contrast agent in larger facilities. The results of this study are valid in Japan.
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X-RAY SPECTROMETRY, Jul 30, 2019 Peer-reviewed
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Radiation Protection Dosimetry, Mar, 2019 Peer-reviewed
Misc.
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臨床検査学教育, 9(2) 156-162, Sep, 2017本学では建学以来、多職種連携教育プログラムとして「アセンブリ」を実施している。平成27年度より医学部医学科と医療科学部6学科の全7学科の2年生を対象として、チームワークと地域連携強化を意識したプロジェクト活動を実践するアセンブリIIを開始した。平成28年度は合計611名の学生を対象とし、各学科の学生で構成される混成チーム96チーム(5〜8名/1チーム)を編成して、学外にて地域連携やボランティア活動を行うプロジェクト、またキャンパス内あるいは大学病院内で多様な活動を支援するプロジェクトなど計61のプロジェクト活動を実施した。活動終了後に実施した学生に対するアンケート調査では、66.7%が活動は有意義だったと回答し、コミュニケーション能力の向上に繋がったようである。アセンブリIIは、将来医療の専門職として社会に貢献するために必要な専門職連携の基盤を養成する上で、有意義な活動であると思われた。(著者抄録)
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臨床検査学教育, 9(2) 156-162, Sep, 2017本学では建学以来、多職種連携教育プログラムとして「アセンブリ」を実施している。平成27年度より医学部医学科と医療科学部6学科の全7学科の2年生を対象として、チームワークと地域連携強化を意識したプロジェクト活動を実践するアセンブリIIを開始した。平成28年度は合計611名の学生を対象とし、各学科の学生で構成される混成チーム96チーム(5〜8名/1チーム)を編成して、学外にて地域連携やボランティア活動を行うプロジェクト、またキャンパス内あるいは大学病院内で多様な活動を支援するプロジェクトなど計61のプロジェクト活動を実施した。活動終了後に実施した学生に対するアンケート調査では、66.7%が活動は有意義だったと回答し、コミュニケーション能力の向上に繋がったようである。アセンブリIIは、将来医療の専門職として社会に貢献するために必要な専門職連携の基盤を養成する上で、有意義な活動であると思われた。(著者抄録)
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Open Medical Imaging Journal, 6 89-96, 2012 Peer-reviewedPurpose: The incident at the Fukushima Daiichi nuclear power station in 2011 has again raised concerns with the public regarding radiation exposure, especially so in medical workers and patients undergoing treatment involving the use of radiation. Radioisotopes are currently used during sentinel node navigation surgery (SNNS) in operating rooms without radiation monitoring. To re-evaluate the safety issues, the potential effective dose (E poten) from 99mTc-tin (-Sn) colloid in breast cancer surgery was estimated and personal dose equivalents, H p(10) and H p(0.07), were measured during SNNS. Materials and methods: Seventeen breast cancer patients were enrolled. One day before SNNS, 99mTc-Sn colloid was injected around the tumor and radiation exposure rates were measured using survey meters. Personal dose equivalents for the surgical workers were measured. H p(10) and H p(0.07) for the body and H p(0.07) for the hands were recorded using semiconductor detectors and ring-type glass dosimeters. Results: The maximum E poten was 29 μSv per 74 MBq injection. The maximum H p(10) for the primary and assisting surgeons, nurse, and anesthetist was 3.7, 1.4, 0.3 and 0.6 μSv per SNNS, respectively. The maximum H p(0.07) for the hands was 100 μSv. Maximum radiocontamination 20 times higher than background (0.05 μSv/h) was detected in bloody gauze. Conclusion: The workers' radiation dose exposure from SNNS was not high, although radiation management such as a temporary cooling off period may be required. © Ejiri et al.
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KEK Proceedings, 75-81, Sep, 2010
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Medicine and Biology, 153(8) 286-291, Aug, 2009 Peer-reviewed
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IRPA-12Proceedings, 1-5, Aug, 2008
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NATURAL RADIATION ENVIRONMENT, 1034 177-+, 2008Measurements of radon and thoron exhalation rates have been done using the radon and thoron exhalation rate measuring instrument adopting the accumulation method. We obtained the 111 data in the 40 sites of the 14 prefectures in Japan. The arithmetic average value of the radon and thoron exhalation rates by all 111 data were obtained to be 8.6 mBq.m(-2).s(-1) and 0.80 Bq.m(-2).s(-1) respectively, and we have reported the radon and thoron exhalation rates in relation to the geological features. The relation between the exhalation rate and geology was shown that the exhalation rate had an increasing tendency in order of basic rock, neutral rock and acidic rock. We made the nationwide exhalation-rate map using the survey data of exhalation-rate of radon and thoron and the geological distribution map.
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NATURAL RADIATION ENVIRONMENT, 1034 322-325, 2008Radioactivity of 6 fertilizer samples, 7 china clay samples and 5 china glaze samples, which are commonly used in Japan, was measured using a NaI(Tl) scintillation spectrometer. Potassium activity of fertilizer was almost 540-740 Bq/kg, and the highest activity was 9,100 Bq/kg. Activity of fertilizer was 10 times higher for potassium than for uranium-series. Furthermore, these activities were 25 times for potassium and 18 times for uranium-series in comparison with those in natural soil. In china clay, activities of potassium, uranium-series nuclides and thorium-series nuclides were 543823 Bq/kg, 74.6-94.3 Bq/kg, and 86.3-128 Bq/kg, respectively. These were 1.5-2.2, 2.1-2.6 and 2.3-3.5 times higher than activity of common soil. Activity of glaze was almost equal to that of china clay.
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NATURAL RADIATION ENVIRONMENT, 1034 498-+, 2008The gamma-ray dose rates were measured in Gifu and Tokushima Prefectures in Japan. Measurements were carried out by the car-borne survey method. The dose rate in basaltic terrain in Tokushima prefecture was almost same as average of basaltic terrain in Japan. On the other hand, the dose rate in basaltic terrain in Gifu Prefecture was not same. In situ measurement of terrestrial gamma-ray dose rate was carried out in this terrain to examine its cause. As a result, it was estimated that soil of rhyolite which attributed to neighbor terrain have deposited on this terrain.
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Medicine and Biology, 150(10) 366-371, Oct, 2006 Peer-reviewed
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Proceedings of the third International Workshop on EGS, 224-229, Jun, 2005
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放射線防護分科会会誌, (20) 39-39, Apr 8, 2005
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Medicine and Biology, 148(8) 11-15, Aug, 2004 Peer-reviewed
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IRPA-11, 1-7, May, 2004
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放射線防護分科会会誌, (18) 58-58, Apr 9, 2004
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放射線防護分科会会誌, (16) 43-43, Apr 11, 2003
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放射線防護分科会会誌, (14) 42-42, Apr 4, 2002【目的】胸部X線単純写真における画質向上は、高管電圧撮影による診断領域の拡大と肋骨陰影の減退が必要不可欠である。また、それに伴い高格子比Gridによる散乱線除去が重要となる。しかし、病室撮影での胸部準高圧撮影における散乱線除去を目的としたr8:1 Gridの使用は、GridによるMisalignmentにより臨床上たびたび問題となる。今回、比較的Misalignmentの出現を来たさないr3:1 Gridと銅板を併用したCR胸部病室撮影について、撮影管電圧及び散乱線除去をMisalignmentを含めて検討したので報告します。【使用機器】・CR読取装置:FCR3500(FUJI FILM社製)・IP板:CR CASSETTE ST-VN(FUJI FILM社製)・Phantom:胸部ファントム(京都化学社製)・Grid:MS Xレイグリッドr3,r5,r6,r8(N40,fo 100)・自作成フィルター:銅(0.1mm)+アルミニウム(1.0mm)の合板・ポータブル装置:Sirius 80N(HITACHI社製)・蛍光量計:MODEL F-11(ALCO社製)・電離箱:MODEL 9015,6.0cc指頭型電離箱(Radcal杜製)【方法】(1)JIS(Z4910)規格におけるグリッド及び銅板の物理的性能評価。(2)管電圧の変化に伴う露出倍数、一次線含有率、及びグリッドと銅板の散乱線除去率の検討。(3)各幾何学的配置の歪(Focusの傾斜、Gridの傾斜、Center off、foの延長)によるMisalignmentの発生に伴った、グリッド透過線量の検討及び、ファントム画像の比較検討。(4)管電圧の変化に伴う画質の比較、及び被曝線量の検討。【結果】(1)Cu単体の一次線透過率はr5と同程度であった。(2)r3+Cuの露出倍数は低管電圧でr8、高管電圧でr6と同程度となった。一次線含有量はr5、一次線透過率はr8と同程度であった。(3)幾何学的配置については、foの延長、管球の傾斜、及びグリッドの傾斜による組み合わせで、左右の濃度差が最大となった。(4)r3+Cuの表面入射線量はr5〜r6と同程度であった。また、管電圧の上昇に伴い、表面入射線量の減弱率が他のものに比べ著明であった。【考察】Misalignmentの要因となる条件は、一般的に起こし易い。またその条件の組み合わせにより、発生状態は異なる。r3 GridはFocusの角度、及びfoの設定を正確に行なう事により、Misalignmentの出現はほとんど問題にならないが、被写体厚が厚く、管電圧が90kVを超える場合、散乱線除去率が低下し、CR画像の劣化が著明となる。しかし銅板による散乱線除去を利用する事により、r3の準高圧撮影領域に対する問題点は除去され、総合的に胸部病室撮影の画質向上に有用性が高いと考えられた。[table][table][table][table]
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小児放射線技術, 26(26) 60-63, Feb, 2001 Peer-reviewed乳幼児胸部撮影において,MS-3P型は管電圧を80kVに設定することにより,画質の維持が可能であり,また附加フィルターを使用しての被ばく線量低減を考慮すれば,より臨床に有用性の高い画像が撮影可能であった
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Annals of Nuclear Medicine, 14(1) 25-32, 2000 Peer-reviewedWe compared early and delayed Tc-99m ECD SPECT scans in 32 SLE patients (Group 1, definite neuropsychiatric disorders Group 2, minor neurologic symptoms or normal) with those of normal controls by visual inspection and semi-quantitative evaluation. With visual interpretation, 13 out of 14 patients in Group 1 (93%) and 7 out of 18 patients in Group 2 (39%) had diffuse uneven decrease in early scans. Seven patients in Group 2 (39%) who had normal early scans demonstrated focal decrease in the medial frontal lobe in delayed scans. With cerebral region to cerebellar ratios, in early scans, the medial frontal lobe in Group 1 and Group 2 was significantly lower than in normal controls, and lateral frontal lobe and occipital lobes in Group 1 were significantly lower than in normal controls. Nevertheless, in delayed scans, every cortical region except for the parietal lobe in Groups 1 and 2 was significantly lower than in normal controls. The retention rates in all regions in SLE patients were significantly lower than in normal controls. No case showed SPECT improvement on follow-up studies in either group in spite of clinical improvement. Delayed Tc-99m ECD brain SPECT of high sensitivity might be useful in detecting CNS involvement. Although the SPECT findings did not correlate with the neuropsychiatric symptoms, early and delayed Tc-99m ECD SPECT seems to provide useful objective diagnostic information in SLE patients.
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EUROPEAN JOURNAL OF NUCLEAR MEDICINE, 26(9) 1104-1104, Sep, 1999
Books and Other Publications
16Presentations
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14th International Congress of The International Radiation Protection Association (IRPA-14), May 9, 2016
Research Projects
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2016 - Mar, 2019
教育内容・方法の工夫(授業評価等を含む)
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件名(英語)放射線関係法規の講義で用いる教科書は内容量が多く、理解しにくい(読みにくい)等の観点から、学生の理解促進のために内容を凝縮・整理した資料を作成する等の工夫を実施している。開始年月日(英語)2012/04/01終了年月日(英語)2016/07/31概要(英語)放射線関連の法令には、診療放射線技師法、医療法、放射線障害防止法、電離放射線障害防止規則等があり、特に放射線障害防止法の法令文は内容量も多く、関連箇所に文章が飛ぶため、学生が理解する上で混乱することが多いという観点から実施。
作成した教科書、教材、参考書
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件名(英語)放射線関係法規(3学年)の講義資料と放射線保健管理学実験(4学年)の実験テキスト開始年月日(英語)2012/04/01終了年月日(英語)2016/07/31概要(英語)放射線関係法規の講義では、放射線障害防止法令(B5サイズ:146頁)における資料を作成。放射線保健管理学実験では、放射線安全管理を実践する上で役立つテーマを選別し、その手技の習得が目的。