Evaluation of the use of regional oxygenation technics to enhance the localization of radioisotopes in tumors.

Abstract

Gray et al. (7) in 1953 demonstrated the relationship between tumor radiation sensitivity and the degree of tissue oxygenation. In 1955 Churchill-Davidson and his associates (3) applied the principle to radiation therapy, utilizing a hyperbaric oxygen chamber to achieve increased tissue saturation with oxygen. The Baylor University group (2, 5, 8) introduced the technic of regional oxygenation with intra-arterial infusions of solutions containing hydrogen peroxide to increase regionally the oxygen saturation. Regional oxygenation achieves several atmospheres of equivalent total oxygen content in the blood and other biologic fluids of the region. This latter technic has been utilized for enhancement of radiation response in the treatment of malignant disease. During the biologic studies associated with the utilization of the technic in radiation therapy, it became apparent that certain radioactive isotopes, when given intra-arterially after the intra-arterial infusion of hydrogen peroxide, would localize preferentially in the malignant tumor being infused (1, 4, 6). With the aid of the electron microscope, multiple breaks in the cellular membrane of the malignant cell were demonstrated following regional oxygenation. Autoradiographic data indicated that the radioactive isotope was indeed distributed and fixed in an intracellular geographic distribution. From the data presented by Mallams and his co-workers (8), the concentration of the administered radioactive isotope in the tumor tissue seemed to be related to this altered cell permeability. The tumor tissue thus appears on the scan as an area of concentration of the radioactive material. The purpose of the present study was to demonstrate the applicability of the technic in cases in which ordinary scanning procedures failed to elucidate the clinical problem. Materials and Methods The technic of regional oxygenation as a means for diagnosis of malignant tumors has been reserved for those patients in whom preliminary radioisotope scans were normal but the clinical status warranted further investigation. Two groups of patients have been studied. In the first group were patients with intracranial lesions in whom the technic in the early studies involved the placement of a catheter via a Rochester needle into the common carotid artery and later into the ascending aorta via the brachial artery. Through the catheter 250 cc of 0.06 to 0.24 per cent solution of hydrogen peroxide! with 25 mg of tolazoline4 (Priscoline) and 1000 U.S.P. units of heparin sodium in Ionosol-T4 is infused under pressure for forty-five to sixty minutes. During the last five minutes of the infusion, 700 μc (10 μc/kg) of mercury-203 or 1500 μc (20 μc/kg) mercury-197 labeled chlormerodrin is injected directly into the infusion tubing by means of a three-way stopcock and flushed with the remaining hydrogen peroxide Ionosol-T solution.