DIRECT ESTIMATION OF LATENT TIME FOR RADIATION-INJURY IN LATE-RESPONDING NORMAL-TISSUES - GUT, LUNG, AND SPINAL-CORD
DIRECT ESTIMATION OF LATENT TIME FOR RADIATION-INJURY IN LATE-RESPONDING NORMAL-TISSUES - GUT, LUNG, AND SPINAL-CORD
复制标题
DOI：
10.1080/09553008914550041
复制
发表时间：
1989-01-01
影响因子：
2.6
通讯作者：
DIXON, DO
中科院分区：
文献类型：
--
作者：
BENTZEN, SM;THAMES, HD;DIXON, DO
为了同时分析放射损伤在正常组织中的潜伏期和分级特征，提出了混合模型。该方法是直接分析定量响应数据的一种扩展。从概念上讲，混合模型的应用是基于生物学观察，即在很宽的剂量范围内，一定比例的受照者永远不会表现出损伤。混合模型允许在分析中使用发生时间。此外，这种类型的模型以自然的方式考虑了时间删减观测，并为建模和分析效应相关延迟提供了适当的框架。将完全修复和不完全修复的混合模型应用于啮齿类动物四个晚期终点的剂量-发生率数据：辐射致肺炎死亡、脊髓照射后腿部瘫痪、辐射致直肠狭窄和肛门排出。辐射引起的肺炎具有效应依赖性潜伏期。这种现象的模型与组织学研究的结果密切相关。有趣的是，在这个终点，危险率的比率并不是恒定的。脊髓放射损伤潜伏期的主要特征是对每分数剂量的强烈依赖。在对这一效应进行校正后，观察到较低效应水平的潜伏时间倾向于较长。对于直肠并发症，单纯放疗与放疗联合顺铂的潜伏期无差异。
Mixture models are proposed for simultaneous analysis of the latency and fractionation characteristics of radiation injury in late-responding normal tissues. The method is an extension of the direct analysis for quantal response data. Conceptually, the application of the mixture model is based on the biological observation that over a wide range of doses a proportion of the irradiated subjects will never express damage. Mixture models allow the time of occurrence to be utilized in the analysis. Furthermore, this type of model takes time-censored observations into account in a natural way and provides an adequate framework for modelling and analysis of effect-dependent latency. Mixture models with complete and incomplete repair are applied to dose-incidence data for four late endpoints in rodents: death from radiation-induced pneumonitis, leg paralysis after spinal-cord irradiation, and radiation-induced rectal stenosis and anal discharge. Radiation-induced pneumonitis had an effect-dependent latency. The modelling of this phenomenon correlates well with the results of histologic studies. Interestingly, the ratio of hazard rates was not constant for this endpoint. The dominating feature in the latency of radiation injury to the spinal cord was a strong dependency on dose per fraction. After correction for this effect a tendency towards a longer latent time for lower effect levels was observed. For the rectal complication, there was no difference between latency with radiation only vs. radiation combined with cis-platin.