Selection of techniques for orthovoltage radiation therapy.

Selection of appropriate orthovoltage radiation techniques (peak kilovoltage plus total filtration) may be based on the following factors: (a) central axis percent depth dose, (b) exposure rate, (c) sensitivity of backscatter factor to size of a blocked field, (d) differential bone energy absorption, (e) penumbra characteristics, and (f) field uniformity. An analysis of these factors as a function of beam quality (i.e. half-value layer) has been performed and a recommendation of a minimal number of techniques (consistent with widely available techniques) is presented.