@article{oai:repo.qst.go.jp:00044843,
 author = {Tanaka, Igunasya and Tanaka, Satoshi and Ichinohe, Kazuaki and Matsushita, Satoru and Matsumoto, Tsuneya and Ohtsu, Yuji and Oghiso, Yoichi and Sato, Fumiaki and 田中 聡 and 一戸 一晃 and 松下 悟 and 松本 恒弥 and 佐藤 文昭},
 issue = {4},
 journal = {Radiation Research},
 month = {Apr},
 note = {Four thousand 8-week-old SPF B6C3F1 mice (2000 of each sex) were divided into four groups, one nonirradiated (control) and three irradiated. The irradiated groups were exposed to 137Cs gamma rays at dose rates of 21, 1.1, and 0.05 mGy day-1 for approximately 400 days with total doses equivalent to 8000, 400 and 20 mGy, respectively. All mice were kept until natural death, and pathological examination was performed to determine the cause of death. Neoplasms accounted for >86.7% of all deaths. Compared to the nonirradiated controls, the frequency of myeloid leukemia in males, soft tissue neoplasmas and malignant granulosa cell tumors in females, and hemangiosarcoma in both sexes exposed to 21 mGy day-1 were significantly increased. The number of multiple primary neoplasms per mouse was significantly increased in mice irradiated at 21 mGy day-1. Significant increases in body weights were obseved from 32 to 60 weeks of age in males and females exposed to 1.1 mGy day-1 and 21 mGy day-1, respectively. Our results suggest that life shortening (Tanaka et al, Radiat. Res. 160, 376-379, 2003) in mice continuously exposed to low-dose-rate gamma rays is due to early death from a variety of neoplasms and not from increased incidence of specific neoplasms.},
 pages = {417--437},
 title = {Cause of Death and Neoplasia in Mice Continuously Exposed to Very Low Dose Rates of Gamma Rays},
 volume = {167},
 year = {2007}
}