Patent ID: 7239684

Claim:
A radiotherapy apparatus comprising: a gantry section; an irradiation head section configured to irradiate therapeutic radiation to a therapeutic field of a target subject; an X-ray source section movably provided on said gantry section and configured to irradiate diagnostic X-rays to the therapeutic field of the target subject; and a sensor array section movably provided on said gantry section and configured to detect the diagnostic X-rays which have transmitted through the target subject and to output diagnostic X-ray image data based on the detected diagnostic X-rays; an image processing unit configured to generate diagnostic images of the therapeutic field based on the diagnostic X-ray image data; a head swing mechanism movably provided on said gantry section and configured to swing said irradiation head section such that the therapeutic radiation outputted from said irradiation head section follows the movement of the therapeutic field; and a control unit configured to carry out position control of said head swing mechanism based on the diagnostic images, a position of said irradiation head section, and a swing state of said irradiation head section such that the irradiated field of said irradiation head section tracks the therapeutic field, and to control said irradiation head section to irradiate the therapeutic radiation after the position control of said head swing mechanism has been carried out; wherein said irradiation head section is movably coupled to said head swing mechanism and said irradiation head section and said head swing mechanism are provided along a line from said gantry section to the therapeutic field; wherein said gantry section comprises first and second gantries, and said head swing mechanism is movably provided on an L type gantry and a robot arm as said first gantry and said X-ray source section and sensor array section are provided on said second gantry.