Abstract：
UNASSIGNED: To examine the distortion of the linear quadratic (LQ) model of in vitro cytogenetic dose response over an extended range of γ-ray doses by analyzing the available literature data, and to establish the dose ranges, in which the LQ dose response curve (DRC) can be most accurately fitted for biological dosimetry.
UNASSIGNED: Data on yields of dicentrics (Dic) or dicentrics plus centric rings (Dic + CR) induced in vitro in human lymphocytes by acute γ-rays were extracted from 108 open sources. The overall dose response dataset in the dose range up to 50 Gy was fitted to a fractional-rational (FR) model, which included a \'basic\' LQ function in the numerator, and a reduction factor dependent on the square of the dose in the denominator. Cytogenetic dose response data obtained at Grigoriev Institute for Medical Radiology, Kharkiv, Ukraine (GIMRO) in the range 0.1 - 20.3 Gy acute γ-rays were fitted to the LQ model with the progressive changing minimum or maximum radiation dose.
UNASSIGNED: The overall dose response, as expected, followed the LQ function in the dose range ≤5 Gy, but in the extended dose range appeared to be S-shaped, with intensive saturation and a plateau at doses ≥22 Gy. Coefficients of the \'basic\' LQ equation in FR model were very close to many published DRCs; calculated asymptote was 17. Fitting of the GIMRO dataset to the LQ model with the shift of the dose range showed the increase in linear coefficient with the increment of either minimum or maximum radiation dose, while the decline of the quadratic coefficient was regulated mostly by the increase of the highest dose. The best goodness of fit, assessed by lower χ2 values, occurred for dose ranges 0.1 - 1.0 Gy; 0.5 - 5.9 Gy; 1.0 - 7.8 Gy; 2.0 - 9.6 Gy, 3.9 - 16.4 Gy and 5.9 - 20.3 Gy. The \'see-saw\' effect in changes of LQ coefficients was confirmed by re-fitting datasets published by other laboratories.
UNASSIGNED: The classical LQ model with fixed coefficients appears to have limited applicability for cytogenetic dosimetry at radiation doses >5 Gy due to the saturation of the dose response. Different response of the LQ coefficients to the changes of the dose range must be considered during the DRC construction. Proper selection of minimum and maximum dose in calibration experiments makes it possible to improve the goodness of fit of the LQ DRC.
UNASSIGNED: Data on yields of dicentrics (Dic) or dicentrics plus centric rings (Dic + CR) induced in vitro in human lymphocytes by acute γ-rays were extracted from 108 open sources. The overall dose response dataset in the dose range up to 50 Gy was fitted to a fractional-rational (FR) model, which included a \'basic\' LQ function in the numerator, and a reduction factor dependent on the square of the dose in the denominator. Cytogenetic dose response data obtained at Grigoriev Institute for Medical Radiology, Kharkiv, Ukraine (GIMRO) in the range 0.1 - 20.3 Gy acute γ-rays were fitted to the LQ model with the progressive changing minimum or maximum radiation dose.
UNASSIGNED: The overall dose response, as expected, followed the LQ function in the dose range ≤5 Gy, but in the extended dose range appeared to be S-shaped, with intensive saturation and a plateau at doses ≥22 Gy. Coefficients of the \'basic\' LQ equation in FR model were very close to many published DRCs; calculated asymptote was 17. Fitting of the GIMRO dataset to the LQ model with the shift of the dose range showed the increase in linear coefficient with the increment of either minimum or maximum radiation dose, while the decline of the quadratic coefficient was regulated mostly by the increase of the highest dose. The best goodness of fit, assessed by lower χ2 values, occurred for dose ranges 0.1 - 1.0 Gy; 0.5 - 5.9 Gy; 1.0 - 7.8 Gy; 2.0 - 9.6 Gy, 3.9 - 16.4 Gy and 5.9 - 20.3 Gy. The \'see-saw\' effect in changes of LQ coefficients was confirmed by re-fitting datasets published by other laboratories.
UNASSIGNED: The classical LQ model with fixed coefficients appears to have limited applicability for cytogenetic dosimetry at radiation doses >5 Gy due to the saturation of the dose response. Different response of the LQ coefficients to the changes of the dose range must be considered during the DRC construction. Proper selection of minimum and maximum dose in calibration experiments makes it possible to improve the goodness of fit of the LQ DRC.
摘要：
■通过分析现有文献数据，在γ射线剂量的扩展范围内检查体外细胞遗传学剂量反应的线性二次（LQ）模型的失真，并建立剂量范围，其中LQ剂量反应曲线（DRC）可以最准确地拟合生物剂量测定。
■从108个开放来源中提取了急性γ射线在人淋巴细胞中体外诱导的双中心（Dic）或双中心加中心环（DicCR）产量的数据。将剂量范围高达50Gy的总剂量反应数据集拟合到分数理性（FR）模型，其中在分子中包含一个\'基本\'LQ函数，和取决于分母中剂量的平方的减少因子。在Grigoriev医学放射学研究所获得的细胞遗传学剂量反应数据，哈尔科夫,乌克兰（GIMRO）在0.1-20.3Gy的急性γ射线范围内拟合到LQ模型，并逐渐变化最小或最大辐射剂量。
■总体剂量反应，正如预期的那样，遵循剂量范围≤5Gy的LQ函数，但是在延长的剂量范围内似乎是S形的，在剂量≥22Gy时具有强烈的饱和度和平台。FR模型中的“基本”LQ方程的系数与许多已发表的DRC非常接近；计算的渐近线为17。将GIMRO数据集拟合到LQ模型，随着剂量范围的变化，线性系数随着最小或最大辐射剂量的增加而增加。而二次系数的下降主要受最高剂量增加的调节。最好的健康，通过较低的χ2值评估，发生剂量范围0.1-1.0Gy;0.5-5.9Gy;1.0-7.8Gy;2.0-9.6Gy，3.9-16.4Gy和5.9-20.3Gy。通过重新拟合其他实验室发布的数据集，证实了LQ系数变化的“看到”效应。
■由于剂量反应的饱和，具有固定系数的经典LQ模型似乎对辐射剂量>5Gy的细胞遗传学剂量测定具有有限的适用性。在DRC构建过程中，必须考虑LQ系数对剂量范围变化的不同响应。在校准实验中正确选择最小和最大剂量可以提高LQDRC的拟合优度。
■从108个开放来源中提取了急性γ射线在人淋巴细胞中体外诱导的双中心（Dic）或双中心加中心环（DicCR）产量的数据。将剂量范围高达50Gy的总剂量反应数据集拟合到分数理性（FR）模型，其中在分子中包含一个\'基本\'LQ函数，和取决于分母中剂量的平方的减少因子。在Grigoriev医学放射学研究所获得的细胞遗传学剂量反应数据，哈尔科夫,乌克兰（GIMRO）在0.1-20.3Gy的急性γ射线范围内拟合到LQ模型，并逐渐变化最小或最大辐射剂量。
■总体剂量反应，正如预期的那样，遵循剂量范围≤5Gy的LQ函数，但是在延长的剂量范围内似乎是S形的，在剂量≥22Gy时具有强烈的饱和度和平台。FR模型中的“基本”LQ方程的系数与许多已发表的DRC非常接近；计算的渐近线为17。将GIMRO数据集拟合到LQ模型，随着剂量范围的变化，线性系数随着最小或最大辐射剂量的增加而增加。而二次系数的下降主要受最高剂量增加的调节。最好的健康，通过较低的χ2值评估，发生剂量范围0.1-1.0Gy;0.5-5.9Gy;1.0-7.8Gy;2.0-9.6Gy，3.9-16.4Gy和5.9-20.3Gy。通过重新拟合其他实验室发布的数据集，证实了LQ系数变化的“看到”效应。
■由于剂量反应的饱和，具有固定系数的经典LQ模型似乎对辐射剂量>5Gy的细胞遗传学剂量测定具有有限的适用性。在DRC构建过程中，必须考虑LQ系数对剂量范围变化的不同响应。在校准实验中正确选择最小和最大剂量可以提高LQDRC的拟合优度。
