System and method for estimating and manipulating estimated radiation dose

A method for permitting manipulation of an achievable dose distribution estimate deliverable by a radiation delivery apparatus for proposed treatment of a subject, the achievable dose distribution estimate defined over a three-dimensional range of voxels with a dose value for each voxel, the method comprising:

• (a) determining a dose modification voxel for which it is desired to modify the dose value and a corresponding magnitude of desired dose modification;
• (b) for each of a plurality of beams:
• (i) characterizing the beam as a two-dimensional array of beamlets, wherein each beamlet is associated with a corresponding intensity value and a ray line representing a projection of the beamlet into space;
• and
• (ii) identifying one or more dose-change beamlets which have associated ray lines that intersect the dose modification voxel;
• (c) modifying the intensity values of at least one of the dose-change beamlets;
• and
• (d) updating the achievable dose distribution estimate to account for the modified intensity values of the at least one of the dose-change beamlets.