Quantitative measurements of oxygen tension in normal tissues and in the tumours of patients before and after radiotherapy

Abstract

Quantitative measurements of oxygen tension in tumors and normal tissues of patients were made by the oxygen cathode technique before and after radiotherapy. Statistical analysis showed that log oxygen tension has a normal distribution. The ratio (tissue oxygen tension when breathing oxygen/tissue oxygen tension when breathing air) = K, a constant of mean value 2.1 to 2.3 for muscle, subcutaneous tissue, tissues near tumor, and tumor before treatment. Afier radiotherapy, K is sigrificantly higher for tumor, but for no other tissue. The effect of the radiosensitizer Synkavit on the oxygen tension is described. Warming by diathermy reduced tumor oxygen tension and the response to breathing oxygen. The findings encourage use of oxygen inhaled at atmospheric pressure as a radiosensitizer, but patients require 7 to 8 l/min for 30 min, to obtain maximum tumor oxygen tension. (auth)