著者

岩永 正子 Nader Ghotbi 小川 洋二 乗松 奈々 山下 俊一

出版者

長崎大学

雑誌

長崎醫學會雜誌 : Nagasaki Igakkai zasshi (ISSN:03693228)

巻号頁・発行日

vol.81, pp.266-270, 2006-09

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近年18-Fポジトロン放出放射性同位核種を用いたPET(positoron emission tomography)およびPET/CTが悪性腫瘍などの臨床画像診断分野で急速に普及している。しかし,日本と欧米ではPET(PET/CT)の臨床応用に極めて異なる点がある。欧米ではPETは主として確定診断・ステージング・治療後フォローアップなどの癌診療に適用されているが,日本ではそういった癌診療以外に,無症状の健康人に対する癌検診の適用が20%も占めていることが特徴である。PETガン検診の急速な普及の背景には,PET検診センターと旅行会社がタイアップした「PET検診ツアー」ブーム,「数ミリの極微小のがんが発見でき,これまでの検査より癌の発見率が高い」「被曝線量は2.2mSvと年間に受ける自然被曝線量よりも低く安全」という偏った情報のみがマスメディアで過剰宣伝されていることなどが考えられている。日本では以前から医療用被曝の割合が高いことが知られ,PET/CTによる癌検診の普及により新たな医療被曝の増加が懸念される。PET検査の18-Fから出るγ線のエネルギーは高く(511 KeV)被検者だけでなく介護者・医療スタッフの職業被曝の問題もある。PET(PET/CT)の臨床腫瘍学における検査の妥当性・有効性については欧米から多くの報告があるが,PET(PET/CT)による一般健康人の癌検診(いわゆるマス・スクリーニング)は欧米では行われていないこともあって,その妥当性と放射線被曝について評価した研究は非常に少ない。そこで我々は,既知論文・PETモデルセンター・日本人癌罹患率などのデータをもとに,無症状の一般健康人を対象にしたPET(PET/CT)癌検診の検査の妥当性と放射線被曝線量を評価した。

著者

柳田 亮 小川 洋二郎 水落 文夫 鈴木 典 高橋 正則 岩崎 賢一

出版者

一般社団法人日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.67, no.3, pp.417-422, 2012 (Released:2012-06-26)

参考文献数

17

被引用文献数

1

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Objective: Altitude training is frequently used for athletes requiring competitive endurance in an attempt to improve their sea-level performance. However, there has been no study in which the mechanisms by which spontaneous arterial-cardiac baroreflex function changes was examined in responders or nonresponders of altitude training. The purpose of this study was to clarify the different effects of altitude training on baroreflex function between responders and nonresponders. Methods: Twelve university student cross-country skiers (6 men, 6 women; age, 19±1 years) participated in the altitude training in a camp for 3 weeks, which was carried out in accordance with the method of Living High-Training Low. Baroreflex function was estimated by transfer function analysis before and after the training. Results: The responders of the training were 3 men and 2 women, and the nonresponders were 3 men and 4 women. In the responders, the transfer function gain in the high-frequency range significantly increased after the training (28.9→46.5 ms/mmHg p=0.021). On the other hand, no significant change in this index was observed in the nonresponders (25.9→21.2 ms/mmHg p=0.405). Conclusion: As indicated by the results of transfer function gain in the high-frequency range, the baroreflex function in the responders increased significantly after the altitude training, whereas no significant change was observed in the nonresponders.

著者

曷川 元 小川 洋二郎 青木 健 柳田 亮 岩崎 賢一

出版者

日本衛生学会

雑誌

日本衛生学雑誌 (ISSN:00215082)

巻号頁・発行日

vol.67, no.4, pp.508-513, 2012 (Released:2012-10-25)

参考文献数

24

被引用文献数

2

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Objectives: Acute hypoxia may impair dynamic cerebral autoregulation. However, previous studies have been controversial. The difference in methods of estimation of dynamic cerebral autoregulation is reported to be responsible for conflicting reports. We, therefore, conducted this study using two representative methods of estimation of dynamic cerebral autoregulation to test our hypothesis that dynamic cerebral autoregulation is impaired during acute exposure to mild hypoxia. Methods: Eleven healthy men were exposed to 15% oxygen concentration for two hours. They were examined under normoxia (21% O2) and hypoxia (15% O2). The mean arterial pressure (MAP) in the radial artery was measured by tonometry, and cerebral blood flow velocity (CBFv) in the middle cerebral artery was measured by transcranial Doppler ultrasonography. Dynamic cerebral autoregulation was assessed by spectral and transfer function analyses of beat-by-beat changes in MAP and CBFv. Moreover, the dynamic rate of regulation and percentage restoration of CBFv were estimated when a temporal decrease in arterial pressure was induced by thigh-cuff deflation. Results: Arterial oxygen saturation decreased significantly during hypoxia (97±0% to 88±1%), whereas respiratory rate was unchanged, as was steady-state CBFv. With 15% O2, the very-low-frequency power of CBFv variability increased significantly. Transfer function coherence (0.40±0.02 to 0.53±0.05) and gain (0.51±0.07 cm/s/mmHg to 0.79±0.11 cm/s/mmHg) in the very-low-frequency range increased significantly. Moreover, the percentage restoration of CBF velocity determined by thigh-cuff deflation decreased significantly during hypoxia (125±25% to 65±8%). Conclusions: Taken together, these results obtained using two representative methods consistently indicate that mild hypoxia impairs dynamic cerebral autoregulation.