Oncogenic transformation by charged particles of defined LET.
Oncogenic transformation by charged particles of defined LET.
复制标题
定义的 LET 带电粒子的致癌转化。
作者：
Tom K. Hei;K. Komatsu;Eric J. Hall;Marco Zaider
用哥伦比亚大学放射学研究加速器装置产生的确定线性能量转移（LET）的带电粒子照射C3 H/10 T1/2细胞系统后，对肿瘤转化率和细胞毒性进行评分。将单层培养的细胞贴在聚酯薄膜上，用加速质子、氘或氦-3离子照射，并将结果与X射线进行比较。通过使用轨道段模式获得的定义的LET值，范围从10到120千电子伏/微米。对于X射线和LET较低的带电粒子，细胞存活的剂量-反应曲线具有明显的初始肩部。随着LET的增加，肩部的尺寸逐渐减小，对于最高LET，生存曲线近似于剂量的指数函数。同样，转化发生率在检查的剂量范围内与LET直接相关。然而，转换效率似乎接近80和120 keV/微米之间的平台。使用剂量的线性二次函数分析转化数据的转化概率。当使用微剂量学考虑进行分析时，后一个量表明该终点的靶体积为微米量级。
Neoplastic transformation incidence and cytotoxicity were scored in the C3H/10T1/2 cell system following irradiation with charged particles of defined linear energy transfer (LET) produced at the Radiological Research Accelerator Facility of Columbia University. Cells cultured in monolayers, attached to thin Mylar sheets, were irradiated with accelerated protons, deuterons or helium-3 ions, and the results compared with X-rays. Defined LET values obtained by using the track segment mode, ranged from 10 to 120 keV/microns. For X-rays, and for the charged particles of lower LET, the dose-response curves for cell survival have a marked initial shoulder. With increasing LET, there is a progressive decrease in the size of the shoulder and for the highest LETs, survival curves approximate an exponential function of dose. The transformation incidence, likewise, showed a direct correlation to LET over the dose range examined. The efficiencies of transformation, however, appeared to approach a plateau between 80 and 120 keV/micron. Transformation data were analyzed using a linear-quadratic function of dose for the transformation probability. This latter quantity, when analyzed using microdosimetric consideration, suggests that the target volume for this end point is of the order of micrometer.