Gragtmans N J, Myers D K, Johnson J R, Jones A R, Johnson L D
Radiat Res. 1984 Sep;99(3):636-50.
The RBE for tritium was estimated in reference to 200-kVp X rays, using acceleration of breast tumor appearance in the female Sprague-Dawley rat as the end-point. Chronic X-ray doses of 0.3-2.0 Gy were delivered over 10 days. Intraperitoneal injections of tritiated water ranging in concentrations from 45 to 370 MBq/100 g body wt were administered, followed by four additional injections at 2-day intervals and half of the initial concentrations. Seventy-five percent of the total tritium dose was delivered to the mammary gland within the first 10 days and 95% within the first 20 days after the start of the tritium exposure. RBE estimations were based on various criteria including the tumor incidence per Gy at 450 days postirradiation and the time required to induce tumors in 50% of the animals at risk. The results suggest that tritium beta rays are about 1.1-1.3 times more effective than chronic 200-kVp X rays for acceleration of the appearance of rat mammary tumors. However, the uncertainties involved in these calculations are such that the effects of tritium beta rays could not be reliably distinguished from those of chronic 200-kVp X rays. Measured differences in RBE values were slightly larger for the comparison between acute and chronic X rays than for the comparison between chronic tritium beta rays and chronic X rays.
参照200千伏峰值X射线，以雌性斯普拉格-道利大鼠乳腺肿瘤出现的加速情况为终点，估算了氚的相对生物效应（RBE）。在10天内给予0.3 - 2.0 Gy的慢性X射线剂量。腹腔注射浓度范围为45至370 MBq/100 g体重的氚水，随后每隔2天再注射4次，剂量为初始浓度的一半。在氚暴露开始后的前10天内，75%的总氚剂量输送至乳腺，前20天内为95%。RBE的估算基于各种标准，包括辐照后450天每Gy的肿瘤发生率以及使50%的危险动物诱发肿瘤所需的时间。结果表明，氚β射线在加速大鼠乳腺肿瘤出现方面比慢性200千伏峰值X射线有效约1.1 - 1.3倍。然而，这些计算中涉及的不确定性使得氚β射线的效应无法与慢性200千伏峰值X射线的效应可靠地区分。急性和慢性X射线比较时，RBE值的测量差异略大于慢性氚β射线与慢性X射线比较时的差异。
