Apparatus and techniques for the measurement of oxidation-reduction potentials, pH and oxygen tension in vivo

In order to follow the changes which occur in tumours during treatment with radiation, and the effects of radiosensitizing or radioprotecting drugs, apparatus and techniques have been developed to record automatically changes of oxidation-reduction potential on eight different electrodes. Simultaneous records of pH and oxygen tension changes were used as controls in some experiments. The changes of oxygen tension were followed by applying a known small voltage to one electrode and measuring the current which flowed. Calibration of oxygen-tension measurements was attempted by the use of model experiments.