Positioning method realized by computer, and radiotherapy system

A radiotherapy system, comprising:

• a treatment gantry, configured to carry a ray source to emit rays;
• an image guidance system (IGS), comprising at least one group of a detector and a tube that are disposed opposite to each other;
• a treatment couch, configured to carry and move a patient;
• and
• a control equipment, configured to control the IGS to obtain an IGS image at a current gamma angle, perform an image registration on the IGS image and an electronic image and adjust a position of the treatment couch based on an image registration result, after the treatment couch is moved to a first coordinates;
• and
• wherein the control equipment is further configured to:
• acquire a gamma angle for treatment;
• acquire first coordinates of a treatment couch, wherein the first coordinates are coordinates of the treatment couch when a preset shooting point coincides with an imaging point of the IGS;
• acquire a first relative position between the imaging point and an equipment isocenter;
• acquire a second relative position between the imaging point and a gamma angle rotation axis central point, wherein the gamma angle rotation axis central point is a central point of a gamma angle rotation axis of a gamma angle adjustment device which is used for adjusting a gamma angle;
• acquire a third relative position between a target point of an affected part and the gamma angle rotation axis central point at the gamma angle for treatment;
• calculate second coordinates of the treatment couch at the gamma angle for treatment according to the first coordinates, the first relative position, the second relative position, and the third relative position, when the target point coincides with the equipment isocenter;
• and
• adjust the position of the treatment couch according to the second coordinates.

A positioning method realized by a computer, comprising:

• acquiring a gamma angle for treatment;
• acquiring first coordinates of a treatment couch, wherein the first coordinates are coordinates of the treatment couch when a preset shooting point coincides with an imaging point of an image guidance system (IGS);
• acquiring an IGS image at a current gamma angle for treatment of the treatment couch, based on the first coordinates of the treatment couch;
• acquiring an electronic image at the current gamma angle for treatment;
• performing an image registration on the IGS image at the current gamma angle for treatment and the electronic image at the current gamma angle for treatment and adjusting the position of the treatment couch based on an image registration result;
• acquiring a first relative position between the imaging point and an equipment isocenter;
• adjusting the position of the treatment couch according to the first relative position and the first coordinates;
• acquiring a second relative position between the imaging point and a gamma angle rotation axis central point, wherein the gamma angle rotation axis central point is a central point of a gamma angle rotation axis of a gamma angle adjustment device which is used for adjusting a gamma angle;
• acquiring a third relative position between a target point of an affected part and the gamma angle rotation axis central point at the gamma angle for treatment;
• and
• adjusting the position of the treatment couch according to the first coordinates, the first relative position, the second relative position and the third relative position.