Watanabe H, Ogiu T, Nishimura M, Masaoka Y, Kurosumi M, Takahashi T, Oguri T, Shoji S, Katoh O
Department of Environment and Mutation, Hiroshima University, Japan.
J Radiat Res. 1998 Jun;39(2):93-100. doi: 10.1269/jrr.39.93.
The effects of heavy ion and X-ray irradiation on tumorigenesis in B6C3F1 mice were compared. Six-week-old animals were divided into 6 groups and exposed to 0.426 Gy heavy ion irradiation of 290 MeV/u carbon-ion beam (LET 60-210 KeV/micron) at the dose rate of 0.4 +/- 0.2 Gy/min; 0.5 Gy of X-ray irradiation at 0.1 Gy/min or 5 Gy of X-ray irradiation at 1 Gy/min. The mice were killed and an autopsy performed 13.5 months after the whole body irradiation. Body weights were heaviest for both sexes in the 0.5 Gy group and lightest in the 5 Gy one. Total tumor incidences in the males were 30, 56 and 13% respectively in the heavy ion, 5 Gy and 0.5 Gy X-irradiated groups, stomach tumors, lymphomas and adrenal tumors being the most common outcome of the high dose X-rays. Liver tumor induction did not differ significantly among the groups. In the females tumorigenicity was significantly lower for heavy ion than for 0.5 Gy and 5 Gy X-ray irradiation (P < 0.05), the respective incidences, mainly ovary one, being 73%, 17% and 41%. Non-cancerous lesions, such as graying of the hair, glomerular sclerosis and amyloidosis appeared in the 5 Gy group. These findings indicate that 0.426 Gy of heavy ion irradiation induced lower carcinogenicity than 5 Gy of X-irradiation and higher carcinogenicity than that of 0.5 Gy X-irradiation in male mice.
比较了重离子和X射线辐射对B6C3F1小鼠肿瘤发生的影响。将六周龄的动物分为6组，分别接受剂量率为0.4±0.2 Gy/min的290 MeV/u碳离子束（线性能量传递60 - 210 KeV/微米）的0.426 Gy重离子辐射；0.1 Gy/min的0.5 Gy X射线辐射或1 Gy/min的5 Gy X射线辐射。全身照射后13.5个月处死小鼠并进行尸检。0.5 Gy组的雌雄小鼠体重最重，5 Gy组的最轻。重离子、5 Gy和0.5 Gy X射线照射组雄性小鼠的总肿瘤发生率分别为30%、56%和13%，高剂量X射线照射最常见的结果是胃肿瘤、淋巴瘤和肾上腺肿瘤。各组间肝肿瘤诱导率无显著差异。在雌性小鼠中，重离子的致瘤性显著低于0.5 Gy和5 Gy X射线照射（P < 0.05），各自的发生率主要为卵巢肿瘤，分别为73%、17%和41%。5 Gy组出现了毛发变白、肾小球硬化和淀粉样变性等非癌性病变。这些发现表明，0.426 Gy重离子辐射在雄性小鼠中诱导的致癌性低于5 Gy X射线辐射，高于0.5 Gy X射线辐射。
