EVIDENCE FOR REPAIR CAPACITY IN MOUSE-TUMORS RELATIVE TO SKIN

The repair capacity of six different types of mouse tumor has been tested by comparing regrowth delay curves for single doses and two or five fractions. The problem of reoxygenation has been avoided by making the tumors uniformly resistant or sensitive for each irradiation. The repair increments measured were mostly lower in the tumors than in skin. The data were analyzed in terms of the fractional recovered dose (FR). FR values for these tumors at low doses averaged 20-50% compared with 65-90% for skin. It is postulated that this may result from a difference in the initial slope of the survival curve of tumor cells relative to normal cells, rather than from a difference in the value of DQ. © 1979.