Radiation treatment system and method of operating radiation treatment system

A method of operating a radiation treatment system including:

• a couch that carries a treatment target,
• a radiation source,
• a rotation mechanism configured to support the radiation source and to rotate the radiation source around the couch,
• a sensor configured to detect radiation transmitted through the treatment target,
• a head swing mechanism configured to swing the radiation source so as to swing an irradiation axis of the radiation,
• a multi-leaf collimator configured to partially shield the radiation so as to form a shape of an irradiation range of the radiation,
• a control unit configured to control the radiation source and the rotation mechanism, the method comprising steps executed by the control unit:
• executing rotation irradiation in which the radiation is emitted from the radiation source while the radiation source is rotated by the rotation mechanism, wherein a first irradiation and a second irradiation are the rotation irradiation in which irradiation axes of the radiation are different and trajectories of the rotation performed by the rotation mechanism are the same;
• setting an irradiation plan in which an irradiation range of the first irradiation and an irradiation range of the second irradiation partially overlap;
• controlling an integrated amount of the radiation emitted to the overlapping portion by causing the multi-leaf collimator to operate at any time while performing the irradiation from the radiation source;
• and
• selectively obtaining a difference between a radiation dose in the irradiation plan and a radiation dose actually emitted to the overlapping portion based on a detection result obtained by the sensor and reflect the difference in a subsequent irradiation.