Studies of bone and soft‐tissue tumours induced in rats with radioactive cerium chloride

A colloidal suspension of radioactive cerium chloride was inoculated into the hind legs of Sprague Dawley rats. Bone and soft‐tissue tumours were induced at the site of inoculation in 77% of the animals. All bone tumours were osteogenic osteo‐sarcomas. Soft tissue tumours were mostly malignant and were of various histological types, predominantly fibrosarcomas, haemangiopericytomas, angiosarcomas and rhabdomyosarcomas. A kinetic study showed that the doubling time (DT) of tumours was closely correlated with the anatomical site of tumour development: bone tumours had a DT of 17.4±4.3 days and malignant tumours which developed in soft tissues had a DT ranging from 7.4 to 8.4 days with the exception of two haeman‐giosarcomas which had a long DT of 17±0.6 days. Pulmonary metastases were frequent for osteo‐sarcomas and tumours of vascular origin. This model of induction of bone and soft‐tissue tumours in rats by injection of a colloidal suspension of radioactive cerium chloride offers the possibility of more comprehensive physiopathological and kinetic studies of these tumours and may constitute a good model for their human counterparts.