Risk analysis: Divergent models and convergent interpretations

Citation
Ba. Carnes et N. Gavrilova, Risk analysis: Divergent models and convergent interpretations, RADIAT RES, 156(5), 2001, pp. 628-630
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
RADIATION RESEARCH
ISSN journal
0033-7587 → ACNP
Volume
156
Issue
5
Year of publication
2001
Part
2
Pages
628 - 630
Database
ISI
SICI code
0033-7587(200111)156:5<628:RADMAC>2.0.ZU;2-N
Abstract
Material presented at a NASA-sponsored workshop on risk models for exposure conditions relevant to prolonged space flight are described in this paper. Analyses used mortality data from experiments conducted at Argonne Nationa l Laboratory on the long-term effects of external whole-body irradiation on B6CF(1) mice by Co-60 gamma rays and fission neutrons delivered as a singl e exposure or protracted over either 24 or 60 once-weekly exposures. The ma ximum dose considered was restricted to 1 Gy for neutrons and 10 Gy for gam ma rays. Proportional hazard models were used to investigate the shape of t he dose response at these lower doses for deaths caused by solid-tissue tum ors and tumors of either connective or epithelial tissue origin. For protra cted exposures, a significant mortality effect was detected at a neutron do se of 14 cGy and a gamma -ray dose of 3 Gy. For single exposures, radiation -induced mortality for neutrons also occurred within the range of 10-20 cGy , but dropped to 86 cGy for gamma rays. Plots of risk relative to control e stimated for each observed dose gave a visual impression of nonlinearity fo r both neutrons and gamma rays. At least for solid-tissue tumors, male and female mortality was nearly identical for gamma -ray exposures, but mortali ty risks for females were higher than for males for neutron exposures. As e xpected, protracting the gamma -ray dose reduced mortality risks. Although curvature consistent with that observed visually could be detected by a mod el parameterized to detect curvature, a relative risk term containing only a simple term for total dose was usually sufficient to describe the dose re sponse. Although detectable mortality for the three pathology end points co nsidered typically occurred at the same level of dose, the highest risks we re almost always associated with deaths caused by tumors of epithelial tiss ue origin. (C) 2001 by Radiation Research Society.