A nomographic technique for the isocentric computation of cobalt 60 central ray depth dose.

Abstract A nomographic technique for computation of depth dose of 60Co at areas along the central axis is presented. A calculator composed of 2 sets of graphs and 2 pointers connected by an elastic cursor is used to obtain the depth dose rather than working inverse square law calculations and using TAR and TMR tables as has been previously required for isocentric teletherapy computations. The feasibility of extending this calculator design to other high energy teletherapy machines is discussed.