Fully-spherical radiation therapy system

A fully-spherical radiation therapy system, comprising a multi-degree-of-freedom robot, a linear accelerator and a double-image-guided positioning mechanism, wherein

• the double-image-guided positioning mechanism comprises four ray sources and two ray detectors, and the four ray sources comprise a first ray source, a second ray source a third ray source and a fourth ray source;
• an intersection of two beams emitted by the first ray source and the second ray source is a low-level treatment center, and a first actual projection and a second actual projection are generated on the two ray detectors;
• an intersection of two beams emitted by the third ray source and the fourth ray source is a high-level treatment center, two actual projections are generated on the two ray detectors and then are converted into a first virtual projection and a second virtual projection, respectively;
• a plurality of treatment nodes with the low-level treatment center as a spherical center and a plurality of treatment nodes with the high-level treatment center as a spherical center form a fully-spherical treatment space;
• the multi-degree-of-freedom robot carries the linear accelerator, the multi-degree-of-freedom robot forms a spherical treatment space above and on two sides of a patient around the low-level treatment center and forms a spherical treatment space below and on two sides of the patient around the high-level treatment center;
• the two ray detectors are each flat-panel detectors;
• a beam emitted by a ray source corresponding to the low-level treatment center image-guided positioning mechanism is perpendicular to an actual projection plane of a corresponding flat-panel detector so that an orthographically projected X-ray image is generated;
• a beam emitted by a ray source corresponding to the high-level treatment center image-guided positioning mechanism is not perpendicular to an actual projection plane of a corresponding flat-panel detector so that an obliquely projected X-ray image is generated;
• and
• the obliquely projected X-ray image is converted to a virtual imaging plane to obtain an orthographically projected virtual X-ray image, (x1,y1) represents a coordinate point on a coordinate system of an oblique projection plane x1py1, and (x1,y1) is converted to a corresponding coordinate point (x2,y2) on a coordinate system of a virtual orthographic projection plane x2py2 through following formulas:
• y
• 2
• =
• d
• *
• y
• 1
• ⁢
• cos
• ⁢
• γ
• d
• -
• y
• 1
• ⁢
• sin
• ⁢
• γ
• ,
• and
• x
• 2
• =
• (
• d
• d
• -
• y
• 1
• ⁢
• sin
• ⁢
• γ
• )
• 2
• ⁢
• (
• x
• 1
• 2
• +
• (
• y
• 1
• ⁢
• cos
• ⁢
• γ
• )
• 2
• )
• -
• y
• 2
• 2
• ;
• wherein γ represents an included angle between a plane of the coordinate system of the oblique projection plane and a plane of the coordinate system of the virtual orthographic projection plane and d represents a distance from a central point of an emission source of an X-ray tube to a central point of a corresponding flat-panel detector.