Hahn F F, Boecker B B, Griffith W C, Muggenburg B A
Inhalation Toxicology Research Institute, Albuquerque, New Mexico 87185, USA.
Radiat Res. 1997 Jan;147(1):92-108.
The biological effects of 144Ce were studied in beagle dogs that were exposed to graded activity levels of 144CeCl3 via a single, brief inhalation exposure and observed for their life span. The long-term retained body burdens ranged from 0.06 to 13 MBq/kg with a median of 1.2 MBq/kg. After a short residence time in the lung, most of the 144Ce was translocated to liver and skeleton, where the 144Ce was retained with a half-time approaching the physical half-life of 144Ce, 284 days. Significant radiation doses were delivered to the lung, 28 Gy (median) and 2.5-370 Gy (range); liver, 68 Gy (median) and 6.1-250 Gy (range); and skeleton, 21 Gy (median) and 1.9-100 Gy (range). Lesions induced by the beta-particle radiation were noted in the lung, liver, skeleton, bone marrow, and oral and nasal mucosae closely associated with bone. Early deaths (within 2.5 years) were generally related to hematological dyscrasia, radiation pneumonitis, or hepatocellular degeneration and atrophy. Neoplasms that occurred relatively early, from 2.2-6.8 years after exposure, were noted in the liver, bone, bone marrow and oral mucosa closely associated with bone. Neoplasms that occurred later, beyond 7 years after exposure, were noted in the liver, lung and nasal mucosa closely associated with bone. Increased numbers of neoplasms were not found in two other organs that had relatively high radiation doses, namely the thyroid and kidney. Only one primary bone tumor was noted, but 11 tumors of bone-associated tissues (oral and nasal mucosae and bone marrow) were found. Radiation doses and effects in tissues adjacent to bone, especially those of epithelial or marrow origin, should be considered when determining risks from internally deposited bone-seeking radionuclides, such as 144Ce. The property of 144Ce in depositing on and remaining associated with bone surfaces for long times may be an important factor in the radiation dose to bone marrow and epithelium adjacent to bone.
研究了144Ce对比格犬的生物学效应。这些比格犬通过单次短暂吸入暴露于不同活度水平的144CeCl3，并进行终生观察。长期保留在体内的放射性活度范围为0.06至13 MBq/kg，中位数为1.2 MBq/kg。144Ce在肺中停留较短时间后，大部分转移至肝脏和骨骼，在那里144Ce的滞留半衰期接近其物理半衰期284天。肺、肝脏和骨骼接受了显著的辐射剂量，肺的辐射剂量中位数为28 Gy，范围为2.5 - 370 Gy；肝脏为68 Gy，范围为6.1 - 250 Gy；骨骼为21 Gy，范围为1.9 - 100 Gy。在肺、肝脏、骨骼、骨髓以及与骨骼紧密相关的口腔和鼻粘膜中发现了由β粒子辐射引起的病变。早期死亡（2.5年内）通常与血液系统发育异常、放射性肺炎或肝细胞变性及萎缩有关。暴露后2.2 - 6.8年相对较早发生的肿瘤出现在肝脏、骨骼、骨髓以及与骨骼紧密相关的口腔粘膜中。暴露7年后较晚发生的肿瘤出现在肝脏、肺以及与骨骼紧密相关的鼻粘膜中。在另外两个接受相对高辐射剂量的器官，即甲状腺和肾脏中未发现肿瘤数量增加。仅发现1例原发性骨肿瘤，但发现了11例与骨骼相关组织（口腔和鼻粘膜以及骨髓）的肿瘤。在确定来自体内沉积的亲骨性放射性核素（如144Ce）的风险时，应考虑骨骼邻近组织的辐射剂量和效应，尤其是上皮或骨髓来源的组织。144Ce长时间沉积在骨表面并与之保持关联的特性可能是对骨髓和骨骼邻近上皮产生辐射剂量的一个重要因素。
