@misc{oai:repo.qst.go.jp:00062163,
 author = {Sakai, Kazuo and 酒井 一夫},
 month = {Jul},
 note = {Combined effects of low dose/dose-rate irradiation and a carcinogenic agent
    A group of 5-week-old female C57BL/6N mice, 35 in each group, was irradiated with gamma-rays at 1.2, 0.65, or 0.35 mGy/hr for 35 days. The mice were then injected in the groin with 0.05 mg of 20-methylcholanthrene (MC) dissolved in olive oil and irradiation was continued. A statistically significant suppression of cumulative tumor incidences up to 200 days after MC injection was observed in the group irradiated at 1.2 mGy/hr. TD50 technique revealed that the ability for tumor rejection was increased in the irradiated mice.
     The incidence of thymic lymphoma induced by N-ethyl-N-nitrosourea (ENU) in B6C3F1 mice was synergistically increased by 4 weekly X-irradiation with 0.8 or 1.0 Gy given prior to the ENU administration.  When the weekly dose was reduced to 0.2 or 0.4 Gy, on the other hand, the suppression of tumor incidence was observed. 
     These results indicated that the low dose/dose-rate irradiation may suppress the process of chemical carcinogenesis, while larger doses resulted in its enhancement., The 13th International Congress of Radiation Research},
 title = {The 13th International Congress of Radiation Research},
 year = {2007}
}