Author Kataoka, Takahiro| Yamato, Keiko| Nishiyama, Yuichi| Morii, Yuji| Etani, Reo| Takata, Yuji| Hanamoto, Katsumi| Kawabe, Atsuishi| Sakoda, Akihiro| Ishimori, Yuu| Taguchi, Takehito| Yamaoka, Kiyonori|
Published Date 2012-10
Publication Title Renal Failure
Volume volume34
Issue issue9
Content Type Journal Article
Author Kataoka, Takahiro| Tokunaga, Rikizo| Sakoda, Akihiro| Kawabe, Atsushi| Hanamoto, Katsumi| Yamaoka, Kiyonori|
Published Date 2012-01-27
Publication Title RADIOISOTOPES
Volume volume61
Issue issue1
Content Type Journal Article
Author Nakagawa, Shinya| Kataoka, Takahiro| Sakoda, Akihiro| Ishimori, Yuu| Hanamoto, Katsumi| Yamaoka, Kiyonori|
Published Date 2008-04-25
Publication Title RADIOISOTOPES
Volume volume57
Issue issue4
Content Type Journal Article
Author Kataoka, Takahiro| Sakoda, Akihiro| Yoshimoto, Masaaki| Nakagawa, Shinya| Toyota, Teruaki| Nishiyama, Yuichi| Yamato, Keiko| Ishimori, Yuu| Kawabe, Atsushi| Hanamoto, Katsumi| Taguchi, Takehito| Yamaoka, Kiyonori|
Published Date 2011-07
Publication Title Radiation Protection Dosimetry
Volume volume146
Issue issue1-3
Content Type Journal Article
Author Yamaoka, Kiyonori| Mitsunobu, Fumihiro| Kojima, Shuji| Shibakura, Misako| Kataoka, Takahiro| Hanamoto, Katsumi| Tanizaki, Yoshiro|
Published Date 2005-04-01
Publication Title Journal of Radiation Research
Volume volume46
Issue issue1
Content Type Journal Article
Author Yamaoka, Kiyonori| Kataoka, Takahiro| Nomura, Takaharu| Taguchi, Takehito| Wang, Da-Hong| Mori, Shuji| Hanamoto, Katsumi| Kira, Shohei|
Published Date 2004-05-07
Publication Title Journal of Radiation Research
Volume volume45
Issue issue1
Content Type Journal Article
Author Sakoda, Akihiro| Hanamoto, Katsumi| Ishimori, Yu| Nagamatsu, Tomohiro| Yamaoka, Kiyonori|
Published Date 2008-05
Publication Title Applied Radiation and Isotopes
Volume volume66
Issue issue5
Content Type Journal Article
Author Sakoda, Akihiro| Hanamoto, Katsumi| Ishimori, Yuu| Nagamatsu, Tomohiro| Yamaoka, Kiyonori|
Published Date 2008-06-23
Publication Title Radiation Measurements
Volume volume43
Issue issue1
Content Type Journal Article
JaLCDOI 10.18926/15221
Title Alternative Recent trend of research on the adaptive response induced by low dose radiation and its significance
FullText URL 013_1_007_015.pdf
Author Kusuhara, Toshimasa| Hanamoto, Katsumi| Yamaoka, Kiyonori|
Abstract 本総説は,低線量放射線に対する生体の適応応答(以下,適応応答)に関してその効果を含む最近の研究動向,さらに放射線防護との関係についてまとめたものである。特にこの分野で最も検討が進んでいる「低線量放射線照射の生物学的影響」に関する国際研究組織(BELLE)での動向を中心に報告するものである。即ち,ヒトと自然放射線との共存などヒトの生活環境と適応応答について,適応応答の短期的・長期的効果など適応応答の効果とその生物学的意義について言及した。次に,適応応答の医療などへの応用の可能性について,また,適応応答と放射線防護との関係についても言及した。ここで,低線量放射線にはヒトへの有益な効果があるとの多くの報告例がある半面,放射線防護の面では微量放射線でも危険とする考え方がその根拠にあることがわかった。このため,今後は更なる低線量放射線の生体影響研究を進めるとともに,両者の間の隙間をなくす現実的・合理的な対応が求められている。
Abstract Alternative We reviewed the recent trend of research on the adaptive response induced by low dose radiation and its significance. The following view were obtained. Risk assessment is fundamental to the protection of public health from radiation exposure, but any estimate of risk is subject to numerous major uncertainties. In view of the uncertainties surrounding the shape of dose-response curves at low doses of ionizing radiation. the linear nonthreshold dose-response model is now widely accepted as a paradigm in radiation protection practice and risk analysis. However, interest among scientists in obtaining a more conclusive understanding of the effects of low dose radiation has been evident in recent initiatives, such as adaptive response of low dose radiation, in part to help verify or disprove the linear model. A vigorous worldwide effort is now apparently underway to understand the basic mechanisms underlying the biological effects of low dose radiation. This review presents a series of papers representing the progress going on, which will undoubtably make an important contribution to this field of research.
Keywords 低線量放射線 (low dose radiation) 低濃度化学物質 (low dose chemicals) 適応応答 (adaptive response) 放射線ホルミシス (radiation hormesis) 放射線防護 (radiation protection)
Publication Title 岡山大学医学部保健学科紀要
Published Date 2002-12-25
Volume volume13
Issue issue1
Start Page 7
End Page 15
ISSN 1345-0948
language 日本語
File Version publisher
NAID 120002307469
JaLCDOI 10.18926/15215
Title Alternative A Study of Reconstruction of Magnetic Resonance Image
FullText URL 013_2_077_082.pdf
Author Kato, Hirokazu| Hanamoto, Katsumi| Kuroda, Masahiro| Shibuya, Koichi| Kawasaki, Shoji|
Abstract 磁気共鳴は医学におけるイメージングにおいて重要なモダリティーであり,高度な数学的手法が画像の再構成に取り入れられている。画像再構成の数学的手法および画像再構成にいたるまでの数学的な過程を理解するこは,MRIを学ぶものにとって非常に重要であるが,成書において明確な説明はなされていない。ここでは,MR画像の再構成法を,複素関数と複素フ-リェ係数を用いて導いたので報告する。
Abstract Alternative Magnetic resonance is an important modality for medical imaging, and advanced mathematical techniques are introduced into the reconstruction of images. Clearly understandable explanations of the reconstruction of the MR image and of the mathematical derivation process have not been presented in the texts. Reconstruction of MR image is presented using the complex function and its relevant Fourier coefficients.
Keywords MRI フーリェ変換 (Fourier transform) 画像再構成 (Reconstruction) 周波数エンコード (Frequency encode) 位相画像 (Phase image)
Publication Title 岡山大学医学部保健学科紀要
Published Date 2003-03-20
Volume volume13
Issue issue2
Start Page 77
End Page 82
ISSN 1345-0948
language 日本語
File Version publisher
NAID 120002307578
JaLCDOI 10.18926/15202
Title Alternative Recent trend of research on the nongenotoxic mechanisms of chemical carcinogenesis
FullText URL 014_1_001_014.pdf
Author Yamaoka, Kiyonori| Hanamoto, Katsumi| Ina, Yasuhiro| Kataoka, Takahiro| Kawabe, Atsusi| Sano, Masanobu| Ujifuku, Ayako|
Abstract 本総説は,筆者らが進めている「低線量放射線の健康への影響と医療への応用」に関する研究に資するために調査した,化学発がんの非遺伝毒性的メカニズムの解明に関する最近の動向の概要についてまとめたものである。即ち,非遺伝毒性的発がんにおける細胞増殖,シトクロムP450誘導,酸化的ストレス,および遺伝子発現のそれぞれの役割,並びに量的な応答性について言及した。また,後成的発がんにおけるアポトーシス,およびギャップ結合による情報伝達のそれぞれの役割についても触れた。その結果,非遺伝毒性的な発がん物質の作用の様式とメカニズムやこれによる後成的な影響などについては解明さ れつつあり,特に,これらの発がん物質がゲノムDNAに対し直接的な相互作用,突然変異,修飾などを行う発がん物質とは機能的に異なった作用をすることが明らかになった。また,これらは放射線発がんなど低線量放射線の健康への影響などについて研究する上で,重要な知見となっていることもわかった。
Abstract Alternative To elucidate the health effects by low dose radiation, we reviewed the recent trend of research on the epigenetic mechanisms of chemical carcinogenesis. The following view were obtained. It has become apparent that chemical and physical agents that induce cancer may do so through different cellular and molecular mechanisms. Investigators, recognizing the apparent differences in the ways compounds participate in the carcinogenesis process, coined the phrases "genotoxic" and "epigenetic" in describing activities of chemicals and physical agents that induced cancer. The term "nongenotoxic" has to some extent replaced "epigenetic" and thus, classification of chemical carcinogens has been frequently delegated to either the genotoxic or nongenotoxic categories. Moreover, while much work remains in the understanding of the modes and mechanisms of action of nongenotoxic carcinogens and the epigenetic effects of these agents, it is apparent that this category of chemicals are functionally different than those compounds which directly interact, mutate, and modify genomic DNA.
Keywords 化学発がん (chemical carcinogenesis) 非遺伝毒性 (nongenotoxicity) 後成説 (epigenesis) 酸化的ストレス (oxidative stress) ギャップ結合 (gap junction)
Publication Title 岡山大学医学部保健学科紀要
Published Date 2003-12-25
Volume volume14
Issue issue1
Start Page 1
End Page 14
ISSN 1345-0948
language 日本語
File Version publisher
NAID 120002307816
JaLCDOI 10.18926/15198
Title Alternative Measurement of sampling time in MRI and reconstruction of MR image
FullText URL 014_2_121_128.pdf
Author Kato, Hirokazu| Hanamoto, Katsumi| Kawasaki, Shoji| Shibuya, Koichi| Kuroda, Masahiro| Koyama, Tadashi|
Abstract MRIにおいてk-spaceを構築するためにはエコー信号をサンプリング時間に従って採取する必要がある.このサンプリング時間を測定するために,FOV(field of view)の左半分にファントムを置くことにより階段関数となるスピン分布を生成した。得られたエコー信号を,階段関数をフ-リェ変換したときに得られるフ-リェ係数と比較することによりサンプリング時間を求めた。得られたサンプリング時間を用いて,MRI MULTI-TEST PHANTOMをMRI装置でスキャンすることにより得られたエコー信号をサンプリングしk-spaceを構築した。このk-spaceをフ-リェ逆変換することによりMRI MULTI-TEST PHANTOMの画像を再構成することができた。
Abstract Alternative Regarding the construction of k-space in MRI, it is necessary to extract the required data from the echo signals with the rate of sampling time. In order to measure the sampling time, a rectangular phantom was placed on the left side of the FOV in the body coil of an MRI equipment, and got analog signals in the sequence of spin echo. The sampling time was determined by comparing the measured signals with the Fourier coefficients obtained by transforming the step function which was similar to the profile of the FOV. The MRI MULTI-TEST PHANTOM was scanned, and the k-space was constructed with the extracted data from the echo signals with the rate of the determined sampling time. The MRI images of the MULTI-TEST PHANTOM were reconstructed by inverse-transforming the obtained k-space.
Keywords MRI フーリェ変換 (Fourier transform) 画像再構成 (reconstruction) サンプリング時間 (sampling time)
Publication Title 岡山大学医学部保健学科紀要
Published Date 2004-03-31
Volume volume14
Issue issue2
Start Page 121
End Page 128
ISSN 1345-0948
language 日本語
File Version publisher
NAID 120002307209
Author Nagamatsu, Tomohiro| Hanamoto, Katsumi| Ono, Toshiro| Yamaoka, Kiyonori|
Published Date 2005-12
Publication Title 環境制御
Volume volume27
Content Type Departmental Bulletin Paper
Author Nagamatsu, Tomohiro| Hanafusa, Tadashi| Kinno, Ikuo| Sakoda, Akihiro| Hanamoto, Katsumi| Yamaoka, Kiyonori| Ono, Toshiro|
Published Date 2008-12
Publication Title 環境制御
Volume volume30
Content Type Journal Article