Control method and device for positioning, radiotherapy system, and storage medium

A control device for positioning, applicable to a radiotherapy system, the radiotherapy system comprising radiotherapy equipment and a depth camera, the radiotherapy equipment comprising a radiation chamber and a treatment couch, and the depth camera being disposed at an end, distal from the radiation chamber, of the treatment couch, the device comprising:

• a processor;
• and
• a memory configured to store a computer program executable by the processor;
• wherein the processor, when loading and running the computer program, is caused to:
• acquire an isocentric coordinate matrix comprising a plurality of first body surface coordinates of a target site in a three-dimensional body surface image of a treatment object on the treatment couch, wherein the three-dimensional body surface image is captured by the depth camera in response to the treatment couch being at a first placement position, the first placement position being any position at which the treatment couch is placeable, and the plurality of first body surface coordinates are coordinates of a plurality of body surface positions in a region corresponding to the target site under a camera coordinate system of the depth camera;
• acquire a plurality of second body surface coordinates of the target site by transforming the plurality of first body surface coordinates using a target transformation matrix corresponding to the first placement position, wherein the plurality of second body surface coordinates are coordinates of the plurality of body surface positions in the target site under an isocentric coordinate system of the radiotherapy equipment, and the target transformation matrix is a transformation matrix between the camera coordinate system and the isocentric coordinate matrix;
• and
• determine, based on the plurality of second body surface coordinates and a contour image of the target site in a treatment plan, a placement offset of the target site under the isocentric coordinate system, so as to control the treatment couch to move until the placement offset of the target site meets a target offset requirement.

A radiotherapy system, comprising:

• radiotherapy equipment, a depth camera, and one or more processors, the radiotherapy equipment comprising:
• a radiation chamber and a treatment couch;
• wherein the depth camera is disposed at an end, distal from the radiation chamber, of the treatment couch;
• and the one or more processors are connected to the depth camera and configured to perform a control method for positioning, wherein the control method for positioning comprises:
• acquiring a plurality of first body surface coordinates of a target site in a three-dimensional body surface image of a treatment object on the treatment couch, wherein the three-dimensional body surface image is captured by the depth camera in response to the treatment couch being at a first placement position, the first placement position being any position at which the treatment couch is placeable, and the plurality of first body surface coordinates are coordinates of a plurality of body surface positions in a region corresponding to the target site under a camera coordinate system of the depth camera;
• acquiring an isocentric coordinate matrix comprising a plurality of second body surface coordinates of the target site by transforming the plurality of first body surface coordinates using a target transformation matrix corresponding to the first placement position, wherein the plurality of second body surface coordinates are coordinates of the plurality of body surface positions in the target site under an isocentric coordinate system of the radiotherapy equipment, and the target transformation matrix is a transformation matrix between the camera coordinate system and the isocentric coordinate matrix;
• and
• determining, based on the plurality of second body surface coordinates and a contour image of the target site in a treatment plan, a placement offset of the target site under the isocentric coordinate system, so as to control the treatment couch to move until the placement offset of the target site upon meets a target offset requirement.