Computer program for central axis dose calculations for high energy photons

A computer program is described for central axis dose calculations for 60Co and 6 MV photons. Fixed distance or isocentric calculations for regular or irregular fields can be performed. Corrections are made for wedges and blocking trays. Tissue-air ratios and percentage depth doses are calculated from scatter-air ratios eliminating the need for empirical formulas. Calculated tissue-air ratios and percentage depth doses for elongated fields agree to within 2 per cent with measured data, eliminating the need for tables of equivalent squares. Calculated values for irregular fields also agree to within 2 per cent with measured data.