Department of Tumor and Diagnostic Pathology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
Faculty of Environmental Studies, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan.
J Radiat Res. 2022 Aug 13;63(Supplement_1):i26-i37. doi: 10.1093/jrr/rrac045.
Internal radiation exposure from neutron-induced radioisotopes that were environmentally activated following an atomic bombing or nuclear accident should be considered for a complete picture of the pathologic effects on survivors. Inhaled hot particles expose neighboring tissues to very high doses of particle beams, which can cause local tissue damage. Experimentally, a few μm of 55MnO2 powder was irradiated with neutrons at a nuclear reactor in order to generate 56MnO2 that emits β-rays. Rats were irradiated via inhalation. Pathological changes in various rat tissues were examined. In addition, the 56Mn β energy spectrum around the particles was calculated to determine the local dose rate and the cumulative dose. This review focuses on our latest pathological findings in lungs with internal radiation injury and discusses the pathological changes of early event damage caused by localized, very high-dose internal radiation exposure, including apoptosis, elastin stigma, emphysema, hemorrhage and severe inflammation. The pathological findings of lung tissue due to internal radiation exposure of 0.1 Gy were severe, with no pathological changes observed due to external exposure to γ radiation at a dose of 2.0 Gy. Therefore, it is suggested that new pathological analysis methods for internal exposure due to radioactive microparticles are required.
对于原子爆炸或核事故之后环境激活的中子诱导放射性同位素所致内照射，应考虑将其纳入对幸存者病理影响的全面分析。吸入的热颗粒使邻近组织受到粒子束的极高剂量照射，从而导致局部组织损伤。在实验中，用中子在核反应堆中辐照几微米的 55MnO2 粉末，以产生发射β射线的 56MnO2。通过吸入对大鼠进行辐照。检查了各种大鼠组织的病理变化。此外，还计算了粒子周围的 56Mn β能谱，以确定局部剂量率和累积剂量。本文重点介绍我们在内照射损伤肺部的最新病理发现，并讨论了局部、极高剂量内照射暴露引起的早期事件损伤的病理变化，包括细胞凋亡、弹性蛋白瘢、肺气肿、出血和严重炎症。0.1 Gy 内照射引起的肺组织病理变化非常严重，而γ射线外照射 2.0 Gy 时则没有观察到病理变化。因此，建议采用新的放射性微粒子内照射的病理分析方法。
