CHLORINE AND SODIUM PERFUSION AND ELECTROLYTE BALANCE IN HUMAN TISSUEAND TUMORS BEFORE AND DURING NEUTRON AND PHOTON RADIOTHERAPY

Radiotherapy with nuclear reactor fission neutrons was applied in 49 c ases of pretreated patients with superficial metastases or relapses fr om primary carcinoma. Measurements of the decay rates of the radiation -induced radioactivity of Ca-49, Cl-38 and Na-24 in the irradiated tis sue resulted in values for the simultaneous local kinetics of chlorine and sodium, and in approximate data on the electrolyte masses. The el ectrolytes were present in nonexchangeable and exchangeable compartmen ts of soft tissue. Exchange times of the intravascular to extravascula r turnover and the frequencies of the exchange fractions were determin ed for a series of irradiations. The results have been interpreted in terms of the mean electrolyte exchange rates, of a standardized functi onal blood flow, and of the supply capacity of the vascular system. In the average of all cases, the regional perfusion was reduced by about 30% by irradiation up to 14 Gy (equivalent photon dose = 45 Gy) conne cted with an increase in the non-exchangeable fractions. After fractio nated doses higher than 14 Gy, functional blood flow and supply capaci ty increased to 120%, and fixed electrolytes were removed from the irr adiated tissue. Data on electrolyte kinetics and vascularity are compa red with the literature.