@misc{oai:repo.qst.go.jp:00068426,
 author = {Ohmachi, Yasushi and Ogiu, Toshiaki and Hiraoka, Takeshi and Hamano, Tsuyoshi and Takada, Masashi and Ishida, Yuka and Nakata, Yukiko and Saigusa, Shin and 大町 康 and 荻生 俊昭 and 平岡 武 and 濱野 毅 and 高田 真志 and 石田 有香 and 三枝 新},
 month = {Aug},
 note = {To evaluate RBE of carcinogenic effect of neutrons, infromations on carcinogenicity of various neutron energies must be needed. However, such an energy dependent effect of neutorns have not yet fully been understood. We started a series of murine carcinogenicity, especially focused on leukaemogenesis, among low energy range (0.5MeV- 10MeV) of neutrons. At the start, to evaluate the carcinogenicity of 10MeV neutron, male C3H/nrs mice, susceptible strain to radiation-induced leukemia, had exposed to neutrons (dose rage: 0.05 - 2Gy ), and to Cs-137-deribed gamma-rays (dose range: 0.2 - 4Gy). Neutron was generated from cyclotron, using d (25 MeV)-Be reaction and the exposures to the animals were conducted using vertical beam line. The estimated forward neutron spectra found 10 MeV as the peak energy. The estimation of neutron and gamma dose distribution in the air found that the irradiated area were covered within 95 -100% relative dose range and that the contamination of gamma-rays was about 5% of neutron dose. The animals are under observation for their life span. The study protocol includes autopsy and systemic histopathology of moribund or died mice, analyses on hematology, chromosomal aberration and molecular pathology of the animals with leukemia. Mice were irradiated with neutrons or gamma-rays from July of 2001 to May of 2002 and the mortarity of each types of radiation has reached up to five percent by the end of this February. The incidence of leukemia in neutron- and gamma-rays-irradiated mice seemed to be given maximum at 2Gy and 3Gy, respectively. The temporal results of gross pathology and histopathology revealed that leukemia, liver tumor, hardarian tumor, lung tumor were the common tumors in the irradiated groups. Since the study is in progress, the updated results will be shown at the conferrence., 12th International Congress of Radiation Research},
 title = {Myeloid-leukaemogenicity study in C3H mouse irradiated with 10MeV fast neutrons-Interim report},
 year = {2003}
}