Empirical representation of dose fields for therapy gamma devices

Given are the empirical expressions for the description of the dose fields obtained on different types of gamma-apparatus. The Thomas and Haybittle model was taken as a basis for the model of the dose field description. To provide conformity between the calculated and experimental data in some regions of the beam profile the other analytical expressions are used. A correlation for description of a three-dimensional dose distribution is offered. The use of the proposed empirical correlations makes it possible to describe relative dose distributions with an error not exceeding 1.5% along the entire region, besides the zone of conjugated half-shadow where the error does not exceed 2.5%