Patent ID: 8938047
Filing Date: 2015-01-20
Classification: A61N

Abstract:
1. A method for optimizing a treatment plan for a patient for a gamma radiation therapy system, the system comprising a radiation therapy unit having a fixed radiation focus point, wherein a collimator of said therapy system is provided with a plurality of collimator passage inlets directing radiation emanating from radioactive sources of a source carrier arrangement of the therapy system to said focus point, said collimator having a plurality of sectors and wherein each sector has a number of states of collimator passage diameters which can be individually adjusted to change a spatial dose distribution surrounding the focus point, said method comprising the steps of: determining a set of shots to be delivered to a plurality of isocenter positions within a target volume of a patient during a treatment session; determining a beam-on time for each respective sector and state for each isocenter during which radiation is to be delivered based on the treatment plan; and for each isocenter position, grouping sectors and states of respective sector in accordance with predetermined rules with respect to beam-on times for respective states of the sectors, wherein sectors and respective states are aggregated for simultaneous delivery of radiation during a predetermined period of time, and wherein the predetermined rules comprise selecting the longest beam-on time for each state of a respective sector for an aggregated simultaneous delivery of radiation and wherein the predetermined period of time for simultaneous delivery of radiation is determined to be the minimum beam-on time for a state of a sector of the aggregated sectors.