Patent ID: 8422631

Claim:
A radiation therapy planning apparatus, comprising: a three-dimensional data collection part configured to collect three-dimensional data representing positions of a plurality of portions of a subject at a single specific timing; a marker position measurement part configured to sequentially measure a specific position of a specific portion out of the plurality of portions, which changes in synchronization with periodic movement of the subject; a position calculation part configured to calculate time-dependent specific positions of the plurality of portions based on the three-dimensional data representing the positions of the plurality of portions of the subject at the single specific timing, and on the time-dependent specific position measured by said marker position measurement part; and a dose calculation part configured to calculate a dose of radiation with which each of the plurality of portions is irradiated, based on planned reference irradiation angles which are irradiation directions of therapeutic radiation, on a planned dose of the therapeutic radiation irradiated at each planned reference irradiation angle, and on the time-dependent positions of the plurality of portions calculated by said position calculation part.