@misc{oai:repo.qst.go.jp:00067449,
 author = {Oghiso, Yoichi and Yamada, Yutaka and Nakamura, Shingo and 小木曽 洋一 and 山田 裕 and 中村 慎吾},
 month = {Aug},
 note = {Life time pulmonary carcinogenesis was compared in female Wistar rats following Internal exposures to alpha-particles or external X-ray irradiation to clarify dose responses and histogenesis of lung tumors. The dose response curve for lung tumor incidences was obtained with a peak incidence of about 97% at 5-6 Gy and a threshold-like dose range less than 0.2 Gy for malignant carcinomas after inhalation exposures of total 600 rats to submicron-sized and polydispersed Pu-239 dioxide aerosols. As compared to the dose response curves with the maximum incidence of approximately 40% at 10 Gy after either whole-body or thoracic X-ray irradiation in total 600 animals, relative biological effectiveness for Pu-induced lung tumors was estimated factor of about 11, while histological types and cellular origins of lung tumors were almost similarly identified to be type II cell- or Clara cell-derived adenomas and adenocarcinomas. For comparisons of mutations of the tumor suppressor gene, p53 related to pulmonary carcinogenesis, PCR-SSCP analysis in combination of direct sequence analysis was performed on DNA extracted from both histological sections of lung tumor specimens. The mutation frequency was about 13% with G to A or C to T transitional point mutations mostly in exons 5 and 6 in total 98 cases of Pu-induced lung tumors, while only 3% of mutation frequency with C to T transition in exon 6 was detected from total 33 cases of X-ray-induced lung tumors. These results indicate differences in radiation quality for pulmonary carcinogenesis in the rat between low LET X-ray and high LET alpha-particles, although the other types of genetic mutations could be associated with the developmental stages., 第１２回国際放射線研究会議（ＩＣＲＲ２００３）},
 title = {Comparisons of pulmonary carcinogenesis in rats after inhalation exposures to 239Pu dioxide aerosols or X-ray irradiation},
 year = {2003}
}