In vivo cell survival and volume response characteristics of rat rhabdomyosarcoma tumors irradiated in the extended peak region of carbon- and neon-ion beams.
In vivo cell survival and volume response characteristics of rat rhabdomyosarcoma tumors irradiated in the extended peak region of carbon- and neon-ion beams.
复制标题
碳离子束和氖离子束扩展峰区照射大鼠横纹肌肉瘤肿瘤的体内细胞存活和体积反应特征。
DOI：
10.2307/3575257
复制
发表时间：
1980
影响因子：
3.4
通讯作者：
J. Lyman
中科院分区：
文献类型：
--
作者：
T. Tenforde;S. Curtis;K. E. Crabtree;S. Tenforde;W. Schilling;J. Howard;J. Lyman
用400 MeV/u碳离子和霓虹束照射大鼠横纹肌肉瘤R1肿瘤的远端4 cm峰值区域，测量细胞存活率。体外克隆形成能力测定用于测定体内肿瘤照射后细胞的存活率。根据呼吸空气和低氧条件下对225千伏X射线的响应，估计细胞的慢性低氧比例为35%。从呼吸空气大鼠肿瘤的存活曲线来看，在10%的存活水平下，碳和霓离子辐射峰值的RBE/sub0//sub1/值分别为2.0和3.1。在低氧条件下，峰碳和霓离子的RBE/sub0//sub1/值分别为2.0和3.3。相对于碳离子辐射，霓离子的氧效应减弱。两个重荷电粒子束的RBE值也是通过测量肿瘤在照射后的消退和再生长来确定的。根据延长生长延迟50天所需的X射线和带电粒子剂量之比，峰碳和霓离子的RBE/sub50/值分别为2.3和2.9。这些RBE值与在细胞存活研究中获得的值相似。在一定程度上，它们反映了大量的低氧细胞，表明对于放射抵抗低氧肿瘤的治疗，峰值霓离子比峰值碳离子具有更大的治疗潜力。
Cell survival was measured for rat rhabdomyosarcoma R1 tumors irradiated in the distal 4-cm peak region of 400 MeV/u carbon- and neon-ion beams. An in vitro assay for clonogenic capacity was used to determine the surviing fraction of cells following in vivo tumor irradiation. Based on the response to 225-kV x rays under air-breathing and hypoxic conditions, it was estimated that the chronically hypoxic fraction of cells is 35%. From survival curves for tumors irradiated in air-breathing rats, RBE/sub 0/ /sub 1/ values determined at the 10% survival level were 2.0 and 3.1 for the peak carbon- and neon-ion radiation, respectively. Under hypoxic conditions, RBE/sub 0/ /sub 1/ values for peak carbon and neon ions were, respectively, 2.0 and 3.3 A diminshed oxygen effect was observed for the neon-ion relative to the carbon-ion radiation. Values of RBE for the two heavy charged-particle beams were also determined from measurements of tumor regression and regrowth following irradiation. Based on the ratio of x-ray to charged-particle doses required to produe a growth delay of 50 days, RBE/sub 50/ values for peak carbon and neon ions were 2.3 and 2.9, respectively. These RBE values are similar to those obtained in the cell survival studiesmore » and, to the extent that they reflect a large population of hypoxic cells, indicate that peak neon ions have a greater therapeutic potential than peak carbon ions for the treatment of radioresistant hypoxic tumors.« less