Retention of labelled 5-iodo-2-deoxyuridine after intratumorous injection as a possible indicator of the cellular kinetics.

On the basis of an experimental model of the Lewis lung carcinoma a possibility was checked of obtaining basic kinetic data about the individual proliferation of tumour cells by a method of measuring the incorporation of labelles 125I 5-iodo-2-deoxyuridine intratumorously with a subsequent measurement of the retained activity in the tumour. These activity, which resides in the tumour for a time longer than 24 hours depends on the fraction of cells, that in the synthetic part of the cell cycle at the time of the injection.