Calculation of the dose delivered to organs outside the radiation beams.

An organ dose calculation based on measurements is described which models the total dose delivered outside a beam from 10 to 50 cm from the field edge. The dose distribution is parametrized for each beam energy as a function of depth, distance from the edge, and field size and shape. The algorithm also takes into account the organ location relative to the beam. Comparisons with measurements in an Alderson phantom using thermoluminescent dosimetry are given for various typical treatments.