Induction of liver tumors by X-rays and fission neutrons in hybrid mice (BC3F1)
Previous data proved that hepatocellular tumours can be induced by X-ray radiation in adulthood, and this effect manifests itself in mouse strains exhibiting either a high or a low spontaneous incidence. Recent studies of the influence of radiation quality on the induction of liver tumours use data from various experiments in which BC3F1 mice were subjected to X-ray or fission neutron whole-body irradiation. Liver tumour occurrence is evaluated as final incidences, with age-adjustment for the differences in mortality rates. Animals irradiated with X-rays express a significantly higher incidence in the dose-interval from 3 to 6 Gy and those irradiated with neutrons in the dose-interval from 0.71 to 1.43 Gy. The statistical methods described by Peto confirm that for both radiation qualities a significant positive increase in the total tumour yield is present. Incidence data are then fitted by radiation action models, with a dose-threshold when appropriate. Incidence data points after neutrons are well fitted by a simple linear equation (P: 91%). In the case of X-ray data the quality of the fits is in general unsatisfactory; however, it can be improved by introducing a practical dose-threshold of 1 Gy (P: 63%, 67% and 92% for the quadratic, linear-quadratic and linear fit, respectively). By assuming no-threshold linearity for both data-sets, an RBE of 4 is estimated.
Bibliographic Reference: Paper presented: 38th Meeting of the Radiation Research Society, New Orleans (US), April 7-12, 1990
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Record Number: 199011021 / Last updated on: 1994-12-01
Original language: en
Available languages: en