[Application of the lethal effect of electron capture decay: attempt to control the growth of an ascitic krebs tumor in mice using 64cu].

We have recently demonstrated the existence of a lethal effect due to the transmutation of 64Cu atoms associated with the DNA of in vitro cultured cells: normal monkey cells (kidney) and malignant human cells (alveolar lung carcinoma). The lethal efficiency per decay is high and even higher for the malignant cells. From these results, we have tried to bring about a regression of an ascitic tumor developing in the mouse. The experiments we described show that it is possible to clearly delay (5 X 10(5) ascitic cells injected at t = 0), even to stop for a given number of animals (1 to 2 X 10(4) ascitic cells injected at t = 0), the growth of the tumor owing to some injections of 64Cu totalling about 3 mCi and carried out from the 6th day following inoculation of the malignant cells.