Radiation therapy apparatus configured to track a tracking object moving in an irradiation object

A radiation therapy apparatus comprising:

• a couch that supports an irradiation target;
• a gantry that is movable around the irradiation target to irradiate the irradiation target on the couch with therapeutic radiation from various angles;
• a fluoroscopic X-ray generation device and an X-ray flat-panel detector that are installed on the gantry and used for acquiring a fluoroscopic X-ray image;
• and
• a control system comprising:
• a CBCT imaging device;
• a moving-object tracking device;
• and
• a central control unit configured to control:
• the CBCT imaging device to perform cone-beam CT imaging by using the fluoroscopic X-ray generation device and the X-ray flat-panel detector to acquire a cone-beam CT image;
• and
• the moving-object tracking device to two-dimensionally track a tracking target object projected within the irradiation target in the fluoroscopic X-ray image, wherein
• the moving-object tracking device transfers a position of each tracking target object on a four-dimensional CT image including a position of the tracking target object in each respiratory phase acquired in advance into a therapy room coordinate system, the CBCT imaging device calculates each intersecting point or a common perpendicular line between or of an inter-phase movement straight line and a tracking target object passing straight line, the CBCT imaging device obtains the inter-phase movement straight line by connecting positions of the tracking target object on the four-dimensional CT image in respiratory phases, the CBCT imaging device obtains an intersecting point as three-dimensional coordinates of the tracking target object when the intersecting point exists, and a point on the common perpendicular line on the inter-phase movement straight line, where the CBCT imaging device obtains the common perpendicular line, which has a shortest length, as the three-dimensional coordinates of the tracking target object when the intersecting point does not exist.

A radiation therapy apparatus comprising:

• a couch that supports an irradiation target;
• a gantry that is movable around the irradiation target to irradiate the irradiation target on the couch with therapeutic radiation from various angles;
• a fluoroscopic X-ray generation device and an X-ray flat-panel detector that are installed on the gantry and used for acquiring a fluoroscopic X-ray image;
• and
• a control system comprising:
• a CBCT imaging device;
• a moving-object tracking device;
• and
• a central control unit configured to control:
• the CBCT imaging device to perform cone-beam CT imaging by using the fluoroscopic X-ray generation device and the X-ray flat-panel detector to acquire a cone-beam CT image;
• and
• the moving-object tracking device to two-dimensionally track a tracking target object projected within the irradiation target in the fluoroscopic X-ray image, wherein
• the moving-object tracking device obtains three-dimensional coordinates of the tracking target object as coordinates that are included in a movement area set in advance, the three-dimensional coordinates being on a tracking target object passing straight line formed by connecting to each other three-dimensional coordinates in a therapy room coordinate system for an image of the tracking target object projected on each fluoroscopic X-ray image and three-dimensional coordinates of the fluoroscopic X-ray generation device, and
• the CBCT imaging device determines a respiratory phase of the irradiation target based on the three- dimensional coordinates of the tracking target object obtained for fluoroscopic X-ray images, and reconstructs a three-dimensional image of the irradiation target from a selected one or more of the fluoroscopic X-ray images in the respiratory phase.

A radiation therapy apparatus comprising:

• a couch that supports an irradiation target;
• a gantry that is movable around the irradiation target to irradiate the irradiation target on the couch with therapeutic radiation from various angles;
• a fluoroscopic X-ray generation device and an X-ray flat-panel detector that are installed on the gantry and used for acquiring a fluoroscopic X-ray image;
• a pair of moving-object tracking X-ray generation devices;
• a pair of moving-object tracking X-ray flat-panel detectors;
• and
• a control system comprising:
• a CBCT imaging device;
• a moving-object tracking device;
• and
• a central control unit configured to control:
• the CBCT imaging device to perform cone-beam CT imaging by using the fluoroscopic X-ray generation device and the X-ray flat-panel detector to acquire a cone-beam CT image;
• the moving-object tracking device to two-dimensionally track a tracking target object projected within the irradiation target in the fluoroscopic X-ray image and to three-dimensionally track the tracking target object on a fluoroscopic X-ray image acquired with the pair of moving-object tracking X-ray generation devices and the pair of moving-object tracking X-ray flat-panel detectors,
• wherein the moving-object tracking device obtains three-dimensional coordinates of the tracking target object as a point on a tracking target object passing straight line formed by connecting to each other three-dimensional coordinates in a therapy room coordinate system for an image of the tracking target object projected on a fluoroscopic X-ray image acquired during the cone-beam CT imaging and three-dimensional coordinates of the fluoroscopic X-ray generation device, the point being any one of:
• (i) a point on a three-dimensional movement trajectory of the tracking target object in the therapy room coordinate system acquired from the moving-object tracking device,
• (ii) a point on a three-dimensional movement trajectory of the tracking target object in the therapy room coordinate system, where a calculated common perpendicular line, at which the three- dimensional movement trajectory and the tracking target object passing straight line perpendicularly intersect, has a shortest length,
• (iii) a point on a tracking target object passing straight line, where a calculated common perpendicular line, at which a three-dimensional movement trajectory of the tracking target object in the therapy room coordinate system and the tracking target object passing straight line perpendicularly intersect, has a shortest length, and
• (iv) a midpoint on a length of a common perpendicular line.