Elmore E, Lao X-Y, Ko M, Rightnar S, Nelson G, Redpath Jl
Department of Radiation Oncology, University of California, Irvine, CA 92697, USA.
Int J Radiat Biol. 2005 Apr;81(4):291-7. doi: 10.1080/09553000500140324.
The aim was to define the dose--response curve for high-energy proton-induced neoplastic transformation in vitro. The HeLa x skin fibroblast human hybrid cell assay was used to determine the frequency of neoplastic transformation following doses of 232 MeV protons (mean linear energy transfer, LET=0.44 keV microm(-1)) in the range 5-600 mGy. Proton irradiations were carried out at the Loma Linda University Proton Treatment Facility, CA, USA. The data indicate no evidence for induction of transformation below a dose of 100 mGy. At doses of 5 and 50 mGy, there is evidence for a possible suppression of transformation frequencies below that for spontaneous transformation. The shape of the dose--response curve for high-energy proton-induced transformation of the human hybrid cell line CGL1 does not follow a linear no-threshold model and shows evidence for a threshold as well as for possible suppression of transformation at doses <100 mGy, similar to that seen for other low-LET radiations.
目的是确定体外高能质子诱导肿瘤转化的剂量-反应曲线。采用HeLa×皮肤成纤维细胞人杂交细胞试验，测定232 MeV质子（平均传能线密度，LET = 0.44 keV·μm⁻¹）剂量在5 - 600 mGy范围内肿瘤转化的频率。质子辐照在美国加利福尼亚州洛马林达大学质子治疗设施进行。数据表明，在100 mGy以下剂量时没有诱导转化的证据。在5和50 mGy剂量时，有证据表明转化频率可能低于自发转化频率。人类杂交细胞系CGL1的高能质子诱导转化的剂量-反应曲线形状不遵循线性无阈模型，显示出存在阈值以及在剂量<100 mGy时可能抑制转化的证据，这与其他低传能线密度辐射所见相似。
