STUDIES OF RADIATION-INDUCED CANCER

这个项目(1)调查了人群中的癌症发病率和死亡率。 暴露于电离辐射，特别是在低剂量水平；(2) 从组织的角度描述辐射诱发癌症的风险 风险、剂量反应、辐射质量、剂量分级、自 暴露、性别、暴露和观察时的年龄，以及可能的修改 其他环境和寄主因素的影响；以及(3)检查， 测试并制定辐射致癌模型，以帮助确定 基本机制。被研究的群体包括日本原子弹幸存者， 和几个有记录的治疗(例如，宫颈)的大型人群 癌症患者)、诊断(例如，结核病患者)以及 职业性(例如，X射线技术员)暴露于电离辐射。 项目成员在为政府提供建议的委员会中服务，以及 国际机构。 研究结果表明：(1)对放射性乳房的易感性 癌症随着暴露年龄的增加而下降，儿童暴露在 10岁是高危人群；(2)反复暴露在相对较低的辐射下 剂量对乳腺癌的未来风险；(3)辐射致癌的风险 癌症可能终生存在；(4)双胞胎的产前x射线增加 儿童罹患癌症的风险；(5)接受过良性照射的儿童 头部和颈部的人有很高的甲状腺和大脑发育风险 (6)9%的甲状腺癌可归因于 儿童头颈部放射治疗；(7)儿童癌症放射治疗 与随后患骨癌的风险增加有关，但与 白血病；(8)骨盆高剂量放射可减少白血病的发生 (9)辐射引起的卵巢损伤可能 降低乳腺癌风险，即使在绝经后的女性中也是如此；(10)染色体 局部全身照射后的像差持续存在于循环中 淋巴细胞超过30年；(11)放射性结肠癌发生在 原子弹幸存者，但不是接受治疗的宫颈癌患者 辐射。

This project (1) examines cancer incidence and mortality among populations exposed to ionizing radiation, especially at low dose levels; (2) characterizes the risk of radiation-induced cancer in terms of tissues at risk, dose response, radiation quality, fractionation of dose, time since exposure, sex, age at exposure and at observation, and possible modifying influences of other environmental and host factors; and (3) examines, tests, and formulates models of radiation carcinogenesis to help define basic mechanisms. Groups studied include the Japanese A-bomb survivors, and several large populations with documented therapeutic (e.g., cervical cancer patients), diagnostic (e.g., tuberculosis patients), and occupational (e.g., x-ray technologists) exposures to ionizing radiation. Program members serve on committees advising the government as well as international agencies. Results of studies suggest that (1) susceptibility to radiogenic breast cancer declines with increasing age at exposure, and children exposed under age 10 are at high risk; (2) repeated exposure to relatively low radiation doses pose some future risk of breast cancer; (3) the risk of radiogenic cancer may remain throughout life; (4) prenatal x-ray in twins increases the risk of childhood cancer; (5) children irradiated for benign conditions of the head and neck are at high risk of developing thyroid and brain neoplasia; (6) 9% of all thyroid cancers may be attributed to prior childhood head and neck irradiation; (7) radiotherpy for childhood cancer was associated with increased risks of subsequent bone cancer but not leukemia; (8) high-dose radiation to the pelvis induces fewer leukemias than other types of exposures; (9) ovarian damage caused by radiation may lower breask cancer risk, even among postmenopausal women; (10) chromosome aberrations following partial-body irradiation persist in circulating lymphocytes for over 30 years; (11) radiogenic colon cancer occurs in atomic bomb survivors but not in cervical cancer patients treated with radition.