Current lung cancer risk estimates after exposure to low-linear energy transfer radiation such as X rays are based on studies of people exposed to such radiation at high dose rates, for example the atomic bomb survivors.
Radiobiology and animal experiments suggest that risks from exposure at low to moderate dose rates, for example medical diagnostic procedures, may be overestimated by such risk models, but data for humans to examine this issue are limited.
In this paper we report on lung cancer mortality between 1950 and 1987 in a cohort of 64,172 Canadian tuberculosis patients, of whom 39% were exposed to highly fractionated multiple chest fluoroscopies leading to a mean lung radiation dose of 1.02 Sv received at moderate dose rates.
These data have been used to estimate the excess relative risk per sievert of lung cancer mortality, and this is compared directly to estimates derived from 75,991 atomic bomb survivors.
Based on 1,178 lung cancer deaths in the fluoroscopy study, there was no evidence of any positive association between risk and dose, with the relative risk at 1 Sv being 1.00 (95% confidence interval 0.94,1.07), which contrasts with that based on the atomic bomb survivors, 1.60 (1.27,1.99).
The difference in effect between the two studies almost certainly did not arise by chance (P=0.0001).
This study provides strong support from data for humans for a substantial fractionation/dose-rate effect for low-linear energy transfer radiation and lung cancer risk.
Mots-clés Pascal : Explosion nucléaire, Survivant, Mortalité, Tumeur maligne, Poumon, Exposition professionnelle, Etude comparative, Canada, Irradiation ionisante, Radioscopie, Etude cohorte, Facteur risque, Homme, Amérique du Nord, Amérique, Epidémiologie, Poumon pathologie, Appareil respiratoire pathologie
Mots-clés Pascal anglais : Nuclear explosion, Survivor, Mortality, Malignant tumor, Lung, Occupational exposure, Comparative study, Canada, Ionizing irradiation, Radioscopy, Cohort study, Risk factor, Human, North America, America, Epidemiology, Lung disease, Respiratory disease
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0358516
Code Inist : 002B30A03B. Création : 01/03/1996.