[Patterns in the development of radiation tumors of the stomach and intestines]

In the experiments on dogs and rats it was shown that gastric and intestinal neoplasms arise under the influence of different kinds of radiation, these may be located in all portions of the stomach and bowel and are of a different histological origin. They are not infrequently primary multiple, mostly benign neoplasms which show multicentric growth. The frequency of tumors appearance, their localization, an average latent period, the degree of malignancy and multiplicity are conditioned by the amount of tissue dosage, the topography of their distribution in the alimentary tract and the level of total irradiation of the organism. With the increased dosage of local irradiation the latent period and multiplicity are decreased, while the incidence of malignancy raised. The optimum levels of the tissue dosage and the time of maximum tumor appearance were determined for each type of radiation.