γ源放射事故受照者呕吐开始时间与全身剂量关系

目的探讨γ源放射事故受照者呕吐开始时间与全身吸收剂量之间的关系。方法采用STATA统计软件包对39例γ源放射事故受照者资料进行回顾性分析。结果全身吸收剂量等于或大于1Gy的受照者呕吐发生率(2227)显著大于剂量在1Gy以下的受照者(112,P<0.001)。出现呕吐的受照者,呕吐开始时间(TD,以h表示)与全身吸收剂量D(Gy)之间的关系符合幂函数模型,其方程式可描述为:TD=(17.45±1.77)D-(2.21±0.30)(n=23,F=50.01,P<0.01,经校正的R2=0.8099)。受照后呕吐开始时间在2h以内的P25、P50和P75剂量分别为4.1、7.6和11Gy;呕吐开始时间大于2h的P25、P50和P75剂量分别为2.0、2.4和2.6Gy。结论在突发核或放射事件可能涉及大量患者的情形下,呕吐开始时间可作为早期分类的一个快速而实用的观察指标,但应注意其局限性。

Relationship between the time of vomiting onset and whole-body dose in victims accidentally exposed to gamma-rays

Objective To explore the mathematical relationship between the time of vomiting onset and whole-body dose in victims accidentally exposed to gamma-rays. Methods The data of 39 historical cases accidentally exposed to gamma-rays were analyzed and tested with STATA statistical software package. Results The frequency of vomiting occurrence in cases with whole-body dose of 1 Gy or more (22/27) was significantly higher than those of within 1 Gy(1/12) (P<0.001). For patients who experienced vomiting, the time of vomiting onset post-irradiation (T_D, in hour) decreased with increase of the whole-body absorbed dose (D, in Gy) according to a power function model, which could be described by the formula: T_D =(17.45±1.77)D^{-(2.21±0.30)}(n=23,F=50.01,P<0.01,adjusted R²=0.8099 ). The P₂₅, P₅₀ and P₇₅ doses for patients appearing vomiting less than 2 hours post-exposure were 4.1 Gy, 7.6 Gy and 11.0 Gy, respectively, and those for the time of vomiting onset more than 2 hours were 2 Gy, 2.4 Gy and 2.59 Gy, respectively. Conclusion From these data, the time of vomiting onset would appear to be a rapid and useful early triage index in radiological emergency circumstances where a large number of patients are anticipated, however, the limitations of which should be taken into consideration.