The impact of basic science radiobiological research is now being recognized of significant importance in clinical radiation oncology. Observations made in the laboratory using animals as'well as tissue culture have led to a better biologic understanding of techniques for altered fractionation, techniques for measuring tumor cell proliferation, the possi bilities and limitations of methods for evaluation of nonrandomized clinical studies in deriving time dose relationships for human tumors as well as a better understanding of repair kinetics in mammalian cells, fractionation sensitivity and...