JaLCDOI 10.18926/15203
Title Alternative A study on the scattering exposure dose in radiotherapy.
FullText URL 014_1_015_022.pdf
Author Kawabe, Atsushi| Nakagiri, Yoshitada| Kobashi, Kazuki| Yasumura, Naoki| Yamashita, Takahiro| Goto, Sachiko| Maruyama, Toshinori| Shibuya, Kouichi| Sugita, Katsuhiko|
Abstract 現代の医療のなかで癌治療において不可欠な存在となった放射線治療。一方,放射線被曝はたとえわずかであってもリスクが伴い,厳しく規制されている。ただし医療被曝はこの限りになく,過去においては癌患者に放射線治療をおこなう際の患部以外の被曝についてはあまり問題視されなかった。これには癌の治療という前提に加え,長期生存の可能性が低く,存命中に晩発障害が発生することが低いと考えられていたからである。しかし,集学的治療が確立した今後の放射線治療においては完治する放射線治療患者が多くなり,治癒後の余命が長くなることが予測される。放射線被曝による確率的影響は閾値がなく,影響は当然現れるであろう。そこで,放射線治療をおこなう際の患者の散乱線被曝線量,治療室内散乱線量,さらに高エネルギー放射線発生装置を取り扱うときに問題となっている中性子を測定した。その結果,測定線量は治療患部外被曝,室内散乱線量ともに無視できない量であることがわかった。中性子については,人体に影響がある線量は検出されなかったが,中性子の存在は室内物品の放射化の可能性を示唆するもので定期的な測定管理が必要である。また,Ⅹ線撮影室用の防護衣による散乱線被曝の低減効果は放射線治療室では無意味であった。
Abstract Alternative In modern medicine, radiotherapy has proved indispensable in the treatment of cancer. However. radiation exposure is a health hazard. and is thus strictly regulated. In the past, incidental exposure was not considered to pose a considerable risk, and because radiotherapy was an effective treatment for cancer and because the possibility of the long-term survival was generally poor, the prevalence of radiation injury was thought to be low. In recent years, however, more patients are making complete recoveries, and it is believed that long-term survival is possible with future radiotherapy techniques. There is no threshold for the stochastic effects of radiation exposure, and thus such effects may be detected even at low levels. In the present study, we measured the radiation exposure due to scattered rays from the patient, incidental radiation levels in the radiotherapy room, and levels of neutron radiation. which is a problem when high-energy X-ray radiotherapy systems are used. The results showed that exposure due to scattered rays and incidental levels in the radiotherapy room cannot be dismissed. and that further investigation is warranted. As for neutron radiation, dosages were below those that are known to influence the human body, but regular measurement is necessary because it may induce radioactivity in otherwise benign equipment. In addition, a protective apron had no effect on the exposure due to scattered rays in the radiotherapy room.
Keywords 散乱線被曝 (Exposure of scattered rays) 中性子 (Neutron) 放射線治療 (Radiotherapy) 確率的影響 (Stochastic effect)
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 15
End Page 22
ISSN 1345-0948
language 日本語
File Version publisher
NAID 120002307504
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
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 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 Nakagawa, Shinya| Kataoka, Takahiro| Mizuguchi, Yuko| Yoshimoto, Masaaki| Sakoda, Akihiro| Nomura, Takaharu| Wang, Da-Hong| Kawabe, Atsushi| Taguchi, Takehito| Yamaoka, Kiyonori|
Published Date 2008-07
Publication Title Journal of Clinical Biochemistry and Nutrition
Volume volume43
Issue issue1
Content Type Journal Article
Author Kawabe, Atsushi|
Published Date 2008-03-25
Publication Title
Content Type Thesis or Dissertation