Tumourigenesis by partial body X-irradiation in mice.

Abstract

The aim of the present experiment was to investigate the late effects of partial body X-irradiation on mice. A total of 428 ddY/SLC female mice 10 weeks old were assigned to the following four groups: (1) head exposure with 950 rad, (2) trunk exposure with 950 rad, (3) lower body exposure with 950 rad, (4) unirradiated control. Mean after survival times with their standard errors were as follows: 430±13 days for head exposure, 354±8 days for trunk exposure, 435±13 days for lower body exposure, 472±14 days for control. Life shortening was 9 percent by head exposure and 25 percent by trunk exposure. Irradiation to the lower body did not induce statistically significant life shortening. Head exposure with 950 rad induced pituitary tumours. Trunk exposure with 950 rad induced ovarian tumours and reduced malignant lymphomas. The reduction may be attributable to the extensive life shortening after trunk exposure. An increase of lung tumours after trunk exposure was not statistically significant. Lower body exposure with 950 rad did not change the tumour spectrum of the control group.