Histopathologic effect of high-energy-particle microbeams on the visual cortex of the mouse brain.
Histopathologic effect of high-energy-particle microbeams on the visual cortex of the mouse brain.
复制标题
高能粒子微束对小鼠大脑视觉皮层的组织病理学影响。
作者：
W. Zeman;H. Curtis;C. P. Baker
用直径分别为1 mm、0.250 mm、0.075 mm和0.025 mm的高能粒子束对小鼠视皮质的放射性损伤进行了组织病理学研究。用最小的微束照射只会导致神经细胞体的完全和明确的破坏。受辐射的神经纤维不会被破坏，也不会对血管造成永久性损害。间质胶质细胞部分保存。在24天内产生这样的损伤所需的剂量非常高，0.025毫米射束的剂量为400,000拉德。阈值剂量非常恒定。这与较大光束产生的损伤形成对比。在这里，要么是由于辐射所致的全组织坏死，要么是神经细胞体的破坏非常稀少且呈片状分布。急性循环障碍和血管延迟性辐射损伤是常见病。在24天内完全摧毁神经细胞所需的剂量是1毫米射束的14000拉德，但这个剂量也会使其他组织成分坏死。这个阈值剂量的范围很广，从9300rad到26000 rad。从观察中可以明显看出，受照射的组织体积越大，组织辐射敏感性的波动就越大；而且组织的辐射敏感性与被照射的组织体积成反比。小鼠大脑皮层对1 mm射线的放射敏感性似乎在很大程度上取决于血管装置的放射敏感性；辐射引起的神经细胞直接坏死似乎是次要的，但它是明显的。在微束照射下，放射敏感性似乎完全由神经细胞本身的放射敏感性决定。
A histopathologic study was made of the radiogenic lesions produced in the mouse visual cortex with highenergy-particle beams 1 mm, 0.250 mm, 0.075 mm, and 0.025 mm in diameter. Irradiation with the smallest microbeams results in a complete and definite destruction of nerve cell bodies only. Irradiated nerve fibers are not destroyed; neither is there permanent damage to vessels. Interstitial glia cells are partly preserved. The dosages necessary to produce such a lesion in 24 days are extremely high, 400,000 rads for a 0.025-mm beam. The threshold dose is very constant. This is in contrast to lesions produced by larger beams. Here, either total tissue necrosis results from the irradiatlon, or destruction of nerve cell bodies is very scant and patchy in distribution. Acute circulatory disturbances and delayed radiation damage of vessels are constant findings. The dosage required to produce a complete destruction of nerve cells withln 24 days is 14000 rads for 1-mm beams, but this dose also renders the other tlssue components necrotic. This threshold dose has a wide range from 9300 rads to 26000 rads. From the observations it is apparent that, the larger the irradiated tissue volume, the greater are the fluctuations in tissue radiosensitivity; andmore » that tissue radiosensitivity is inversely related to the tissue volume being irradiated. Radiosensitivity of mouse brain cortex to 1- mm beams seems to be largely determined by the radiosensitivity of the vascular apparatus; direct nerve cell necrosis by radiation appears to be of secondary importance but it is demonstrable. Wlth microbeam irradiation the radiosensitivity seems to be determined exclusively by the radiosensitivity of the nerve cells themselves.« less