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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Low-dose radiation: Thresholds, bystander effects, and adaptive responses
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Low-dose radiation: Thresholds, bystander effects, and adaptive responses

机译：低剂量辐射：阈值，旁观者效应和适应性反应

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摘要

Ionizing radiation fills the universe. Daily ionizing particles and rays collide with molecules in ≈1% of the 100 trillion cells that make up the average human. These collisions generate clusters of free radicals known as reactive oxygen species that randomly damage cellular constituents including DNA. Certain types of ionizing radiation are more effective at generating reactive oxygen species; one α-particle is at least 10 times more damaging than one γ-ray. To take these differences into account, the Sievert (Sv), a unit that multiplies the absorbed dose in grays (Gy) by the relative effectiveness of the particle or ray to inflict damage, was developed. On this scale, natural background radiation is ≈0.01 mSv/day, although there are areas on earth that have values 5-fold higher, and space-station inhabitants may receive ≈1 mSv/ day. At the other end of the scale, acute exposures of > 150 mSv, a range known as high-dose radiation, have measurable and often serious immediate effects on humans. Between background and high-dose radiation is the range of exposures known as low-dose radiation. Low-dose radiation has no immediately noticeable effects on humans; nevertheless there is great interest in its long-term biological effects, which may include cancer in exposed individu-, als and genetic defects in their progeny.
机译：电离辐射充满整个宇宙。在构成普通人的100万亿个细胞中，每日电离的粒子和射线会与大约1％的分子发生碰撞。这些碰撞会产生称为活性氧的自由基簇，这些自由基会随机破坏包括DNA在内的细胞成分。某些类型的电离辐射在产生活性氧方面更有效。一个α粒子的破坏力至少是一根γ射线的十倍。为了考虑到这些差异，开发了Sievert（Sv），该单元将吸收的灰色剂量（Gy）乘以粒子或射线造成损害的相对效率。在这样的规模上，尽管地球上某些地区的自然辐射值高出5倍，并且自然空间辐射的居民每天可能会收到≈1mSv /天，但自然背景辐射约为0.01 mSv /天。另一方面，> 150 mSv的急性暴露（即高剂量辐射）对人体具有可测量的且通常是严重的即时影响。在本底辐射和高剂量辐射之间是被称为低剂量辐射的照射范围。低剂量辐射不会立即对人类产生明显影响；然而，它的长期生物学作用引起了极大的兴趣，其中可能包括个体暴露的癌症以及其子代的遗传缺陷。

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