Fractionation in Preoperative Irradiation

Abstract

Large total doses (5,000 r, 3,500 r) given in single or large fractions effectively inhibit transplantability. Division of total doses into smaller fractions reduces their effectiveness. A small total dose (2,000 r) given in single or large fractions inhibits transplantability to a lesser degree. Division of this total dose into smaller fractions eliminates its effectiveness almost entirely. Clinically, with preoperative irradiation at high dose levels, the degree of fractionation must still be determined by the judgment of the radiotherapist in his effort to enhance the therapeutic ratio. But, at low dose levels, preoperative irradiation is more effective if little fractionation is used.