Zook B C, Bradley E W, Rogers C C
Department of Pathology, George Washington University Medical Center, Washington, DC 20037.
Int J Radiat Oncol Biol Phys. 1992;23(4):821-30. doi: 10.1016/0360-3016(92)90655-2.
Thirty-nine adult male Beagles received either fast neutron or photon irradiation to the right thorax to determine the relative biological effectiveness of fast neutrons on normal pulmonary tissue. The right anterior abdomen, including the cranial half of the right kidney, was included in the field of irradiation. Twenty-four dogs (six/group) received fast neutrons with an average energy of 15 MeV to total doses of 1000, 1500, 2250, or 3375 cGy in four fractions per week for 6 weeks. Fifteen dogs received 3000, 4500, or 6750 cGy of photons (five/group) in an identical fractionation pattern. All 12 neutron irradiated dogs receiving 3375 and 2250 cGy and 1 of 6 receiving 1500 cGy, developed clinical and clinical pathologic signs of hepatic, pancreatic, and gastrointestinal disturbances, but no signs of renal injury were seen. These 13 dogs died or were euthanatized 47-367 days after irradiation. Only 1 of 5 dogs receiving 6750 cGy of photons developed similar signs and died 708 days post-irradiation. The remaining 11 neutron irradiated dogs and 14 photon irradiated dogs eventually died of other causes. All 39 dogs were necropsied and their kidneys were compared to each other and to control dogs. Radiation induced lesions included hemorrhages, necrosis and disappearance of tubular epithelia, glomerulosclerosis, atrophy and fibrosis. These lesions were associated with degenerative and occlusive vascular changes and were much more severe in the neutron irradiated dogs. The relative biologic effectiveness of fast neutrons for canine kidney assessed by gross and microscopic pathology is approximately 4.5 (6750/1500).
39只成年雄性比格犬接受了右侧胸部的快中子或光子照射，以确定快中子对正常肺组织的相对生物效应。照射野包括右前腹部，包括右肾的上半部分。24只狗（每组6只）接受平均能量为15 MeV的快中子照射，总剂量分别为1000、1500、2250或3375 cGy，每周分4次照射，共6周。15只狗接受了3000、4500或6750 cGy的光子照射（每组5只），照射分割模式相同。所有接受3375和2250 cGy照射的12只中子照射狗以及接受1500 cGy照射的6只狗中的1只，出现了肝脏、胰腺和胃肠道紊乱的临床和临床病理体征，但未观察到肾脏损伤的迹象。这13只狗在照射后47 - 367天死亡或被安乐死。接受6750 cGy光子照射的5只狗中只有1只出现了类似的体征，并在照射后708天死亡。其余11只中子照射狗和14只光子照射狗最终死于其他原因。对所有39只狗进行了尸检，并将它们的肾脏相互比较，并与对照狗的肾脏进行比较。辐射诱导的病变包括出血、肾小管上皮细胞坏死和消失、肾小球硬化、萎缩和纤维化。这些病变与退行性和闭塞性血管变化有关，在中子照射的狗中更为严重。通过大体和显微镜病理学评估，快中子对犬肾的相对生物效应约为4.5（6750/1500）。
