Volume correction factor in time dose relationships in brachytherapy.

Paterson's clinical data about the maximum tolerance doses for various volumes of interstitial implants with Ra-226 delivered in seven days was made use of in deriving volume correction factors phi v and phi'v for TDF and CRE concepts respectively for brachytherapy. The derived volume correction factors phi v for TDF and phi'v for CRE differ from the from the one assumed for CRE by Kirk et al. and implied for TDF by Goitein. A normalising volume of 70 cc has been suggested for both CRE and TDF concepts for brachytherapy. A table showing TDFv, the volume corrected TDF, is presented for various volumes and dose rates for continuous irradiation. The use of this table is illustrated with examples.