Patent ID: 8409071

Claim:
A method of treatment planning for placement of radioactive sources in a tumor in a region of a body comprising the following steps, in the indicated order, of: (a) determining an original prescribed dose for a range of locations within the region of the body; (b) calculating an importance function for the range of locations based on a dose produced by a hypothetical source moved among the range of locations; (c) ranking the range of locations according to the importance function; (d) based on the ranking, identifying a source location not currently reserved for a source and reserving that identified location; (e) creating an evaluation function being a modification of the importance function according to a dose distribution function based on total dose provided by sources reserved at locations; (f) repeating steps (c)-(e) using the evaluation function in lieu of the importance function for steps (c)-(d) until the dose provided by sources at reserved locations matches the original desired dose pattern to within a predetermined matching criterion; and (g) irradiating the region of the body with at least one radioactive source located at each of the reserved locations; wherein calculating the evaluation function increases the importance function by a function related to the total dose provided by hypothetical sources at currently reserved locations and the prescribed dose.