CN107007944A - The method for putting position is calibrated by human projection in a kind of radiotherapy operation - Google Patents

Abstract

The invention discloses calibrate the method for putting position by human projection in a kind of radiotherapy operation.In order to allow patient to be kept when treatment, a posture is motionless, and doctor can be fixed to some patients using radiotherapy localization film.But it is due to that the position that patient is lain on orientation room's bed board and therapeutic room's bed board always there are some deviations, film can be allowed to deform when causing to buckle radiotherapy localization film to patient, largely effect on the effect of radiotherapy.Method disclosed by the invention can first calibrate position of the human body on accelerator bed board before radiotherapy localization film is buckled to patient, make position of the patient on therapeutic room's bed board substantially consistent with orientation room, so as to reduce the deformation of film, it is ensured that radiotherapy quality.

Description

A method for calibrating positioning through human body projection in radiotherapy operation

technical field

The invention discloses a method for calibrating and positioning through human body projection in radiotherapy operation.

Background technique

Radiotherapy positioning is the process in which physicists and operators place the patient's tumor center to the center of the accelerator by moving the treatment bed and the human body. The tumor center is determined by doctors through CT and other medical images, and the dose calculation and irradiation field setting in the treatment plan are all based on this tumor center. The accelerator isocenter refers to the accelerator treatment center. After an accelerator is installed, its isocenter is the determined and unique point in space. During radiotherapy, if the center of the tumor coincides with the center of the accelerator, the patient can get the best treatment effect. However, if the positioning is inaccurate, there will be deviations between the tumor center and the center of the accelerator. During radiotherapy, normal tissues will receive additional radiation, and diseased tissues will not receive sufficient doses of radiation, which will greatly increase the probability of tumor recurrence. big.

Domestic radiotherapy positioning schemes are still based on conventional X-ray and CT simulation positioning. First, in the positioning room, the doctor uses a simulation positioning machine to locate the tumor in the patient's body. The specific process is as follows: let the patient lie on the accelerator bed, fix the patient on the bed with a radiotherapy positioning film, and then scan to determine the center of the tumor. The laser indicator light makes a cross-hair mark on the radiotherapy positioning film. Then the patient goes to the treatment room to receive radiation therapy. The mechanical parameters and geometric parameters of the simulator in the positioning room are the same as those in the treatment room. can coincide with the center of the accelerator. In order to make the patient lie in the same position, the doctor will use the crosshairs on the radiotherapy positioning film to align with the laser indicator light in the computer room for positioning.

In fact, the patient's lying position in the treatment room is not so accurate, and there will always be more or less deviations. At this time, the use of radiotherapy positioning membranes will deform the membranes, thereby greatly reducing the treatment effect. However, if the patient's lying position is confirmed before using the radiotherapy positioning film, the deformation of the film will be within an acceptable range.

In view of the above problems, it is necessary to find a method of calibrating the position of the human body on the bed before using the radiotherapy positioning film.

Contents of the invention

Aiming at the deficiencies of the prior art, the technical problem solved by the present invention is to calibrate the position of the human body on the accelerator bed, reduce the deformation of the radiotherapy positioning film, and improve the quality of radiotherapy. The method adopted is to first calibrate the position of the human body on the bed board before using the radiotherapy positioning film during treatment.

In order to solve the problems of the technologies described above, the technical solution of the present invention is achieved in the following way:

The present invention discloses a method for calibrating positioning through human body projection in radiotherapy surgery, which includes the following steps:

B1: the step of obtaining the projection of the body profile in the medical image coordinate system and the conversion matrix from the infrared monitoring equipment coordinate system to the medical image coordinate system;

B2: the step of obtaining the body profile of the human body in the coordinate system of the infrared monitoring equipment;

B3: A step of calculating the deviation of the projection of the body contour of the human body under the two coordinate systems to adjust the position of the patient.

The step B1 includes the following steps: S1: paste a plurality of positioning devices on the accelerator bed of the positioning room, and perform medical imaging on the patient; S2: open the self-developed software, import the medical image of the patient, and scan the human body in the image along the vertical coronal The projection is made in the direction of the surface, and the projection is recorded as A; S3: Outline the positioning device in the image in the software to obtain the relative positional relationship between all positioning devices; S4: Fix the same number of positioning devices at the same position on the bed board in the treatment room as in S1 The positioning device, open the infrared monitoring equipment; S5: the infrared monitoring equipment tracks the coordinates of the positioning device fixed on the bed and transmits it to the computer, and the computer combines the positional relationship between the positioning devices obtained in step S3 to register and calculate the infrared monitoring Transformation matrix between device coordinate system and medical image coordinate system.

In at least one embodiment of the present invention, the number of positioning devices fixed on the positioning room and the treatment room bed is preferably more than three, so as to ensure that the detected motion of the positioning device can fully represent six degrees of freedom in three-dimensional space (translation and rotation in three directions in a three-dimensional coordinate system). If less than three positioning devices are used, the positioning accuracy will be affected, and even the positioning will be wrong. Generally, more than three positioning devices are selected to avoid positioning errors caused by occlusion.

In at least one embodiment of the present invention, the positioning device is an infrared positioning ball that can be recognized by infrared monitoring equipment, but those skilled in the art should think of using other materials with obvious infrared characteristics Formed other shape marking objects to replace the positioning bead. Therefore, similar technical solutions do not exceed the scope disclosed and claimed by the present invention.

In at least one embodiment of the present invention, projecting the human body in the image along the direction vertical to the coronal plane refers to projecting the patient's side profile onto the bed board.

In at least one embodiment of the present invention, the infrared monitoring device can identify the positioning device and return the real-time coordinates of the positioning device. Infrared monitoring equipment is a device that can obtain the three-dimensional coordinates of the positioning device, but those skilled in the art should think of equipment that obtains the coordinates of the positioning device through other principles and approaches without creative work. Therefore, similar technical solutions do not exceed the scope disclosed and claimed by the present invention.

The step B2 includes the following steps: S6: Let the patient lie on the bed in the treatment room and position it according to the cross marks on the body surface; S7: Use the contour brush to brush vertically along the side of the human body, and the infrared monitoring device transmits the contour brush in real time The coordinates of the upper positioning device are given to the software; S8: The software projects the trajectory of the upper positioning device on the contour brush along the direction perpendicular to the bed board, and the projection is recorded as B;

In at least one embodiment of the present invention, the contour brush is independently invented, the positioning device is fixed on the top of the contour brush, the middle of the contour brush is a straight rod, and an angle meter is fixed at the bottom, and the angle meter shows The angle formed by the straight bar with the horizontal. The positioning device is an infrared positioning ball that can be identified by the infrared monitoring equipment, but those skilled in the art should think of using other shaped marking objects made of other materials with obvious infrared characteristics to replace the The positioning ball described above. Therefore, similar technical solutions do not exceed the scope disclosed and claimed by the present invention.

The step B3 includes the following steps: S9: The computer applies the transformation matrix calculated in S5 to the projection B to transfer it to the coordinate system of the projection A, calculates the deviation between the two projections and adjusts the position of the patient accordingly. S10: Repeat steps S6-S9 until the deviation is within a certain threshold.

The beneficial effect of the invention is that the position of the human body on the bed can be calibrated, the deformation of the radiotherapy positioning film can be reduced, and the quality of radiotherapy can be improved.

Description of drawings

Fig. 1 is a schematic flow chart of the present invention.

Figure 2 is a schematic illustration of a tool contour brush used in the present invention.

Figure 3 is a schematic diagram of the results obtained by the software.

Fig. 4 is a schematic diagram of an application scenario.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Fig. 2, the positioning device on the contour brush is an infrared positioning ball that can be identified by an infrared monitoring device. The surface of the infrared positioning ball is covered with a layer of material that can reflect most of the incident infrared light. The infrared light emitted by the infrared monitoring equipment is reflected back by the small ball, and the infrared monitoring equipment receives the reflected infrared light, analyzes the data and calculates the three-dimensional position coordinates of the small ball, and realizes the purpose of monitoring and positioning the device.

Referring to Figure 2, the goniometer is fixed on the straight rod, and can test the angle formed by the straight rod and the horizontal direction. When measuring the side profile of the human body with the profile brush, ensure that the reading of the goniometer is at 90 degrees. Ensure that the projection of the coordinates of the positioning device on the bed is exactly the projection of the coordinates of the contact point between the straight rod and the human body on the bed. The bottom of the straight rod is a horizontal base plate, and the base plate is vertical to the straight rod, which is used to assist the straight rod to maintain a vertical state.

Referring to Fig. 3, the software obtains the trajectory coordinates of the positioning device, and makes a projection in the direction perpendicular to the bed board. Compared with the projection of the patient's medical anatomical structure image in the direction perpendicular to the coronal plane of the human body, the software gives the adjustment direction and distance of the patient's position.

With reference to Fig. 4, concrete process of the present invention is as follows:

S1: Fix multiple positioning devices on the accelerator bed of the positioning room to perform medical imaging on the patient;

S2: Open the self-developed software, import the patient's medical image, and project the human body in the image along the direction of the vertical coronal plane, and record the projection as A;

S3: Outline the positioning device in the image in the software to obtain the relative positional relationship between all positioning devices;

S4: Fix the same number of positioning devices as in S1 on the same position of the bed board in the treatment room, and turn on the infrared monitoring equipment;

S5: The infrared monitoring equipment tracks the coordinates of the positioning device fixed on the bed and transmits them to the computer. The computer combines the positional relationship between the positioning devices obtained in step S3 to register and calculate the coordinate system of the infrared monitoring equipment and the medical image coordinate system. transformation matrix between them.

S6: Let the patient lie on the bed in the treatment room and position it according to the cross marks on the body surface;

S7: Use the contour brush to brush vertically along the side of the human body, and the infrared monitoring equipment transmits the coordinates of the positioning device on the contour brush to the software in real time;

S8: The software projects the trajectory of the positioning device on the contour brush along the direction perpendicular to the bed board, and the projection is marked as B;

S9: The computer applies the transformation matrix calculated in S5 to the projection B to transfer it to the coordinate system of the projection A, calculates the deviation between the two projections and adjusts the position of the patient accordingly.

S10: Repeat steps S6-S9 until the deviation is within a certain threshold.

Claims (9)

1. the method for putting position is calibrated by human projection in a kind of radiotherapy operation, it is characterised in that：Methods described includes：

Obtain the projection of body side profile and infrared monitoring device coordinate in medical image coordinate system and be tied to medical image coordinate The transition matrix of system；

Obtain body side profile in infrared monitoring device coordinate system；

The deviation of human body side outline projection under Two coordinate system is calculated to adjust patient location.

2. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 1, it is characterised in that institute State and obtain in medical image coordinate system the projection of body side profile and infrared monitoring device coordinate is tied to medical image coordinate system Transition matrix the step of comprise the following steps：S1：Multiple positioners are pasted on orientation room's accelerator bed board, patient is carried out Medical imaging；S2：Independent development software is opened, the medical image of patient is imported, to the human body in image along vertical coronal-plane Direction project, projection be designated as A；S3：Positioner is sketched the contours of in image in software, is obtained between all positioners Relative position relation；S4：Same location fixation in therapeutic room's bed board and same number of positioner in S1, are opened infrared Monitoring device；S5：Infrared monitoring equipment follows the trail of the coordinate for the positioner being fixed on bed board and is transferred to computer, computer With reference to the position relationship between the positioner obtained in step S3, registration, calculating obtain infrared monitoring device coordinate system and medical science Transition matrix between image coordinate system.

3. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 2, it is characterised in that institute It is the infrared positioning bead that can be recognized by the infrared monitoring equipment to state positioner.

4. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 2, it is characterised in that institute It is more than three to state and be fixed on therapeutic room and the quantity of positioner on orientation room's bed board.

5. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 2, it is characterised in that institute It is that the coordinate system of the infrared monitoring equipment is transformed under medical image coordinate system to state transition matrix, can by the transition matrix So that certain coordinate value of point under the coordinate system of infrared monitoring equipment to be converted to the coordinate value under medical image coordinate system.

6. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 1, it is characterised in that institute Stating the step of obtaining body side profile in infrared monitoring device coordinate system includes：S6：Patient is allowed to lie on therapeutic room's bed board simultaneously Position is put according to body surface cross hairs mark；S7：Swiped through along the side vertical of human body with profile brush, infrared monitoring equipment is transmitted in real time Profile paints the coordinate of positioner to software；S8：Direction of the software along vertical bed board paints the fortune of positioner to profile Dynamic rail mark is projected, and projection is designated as B.

7. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 6, it is characterised in that institute State profile brush to be made up of four parts, be respectively：(1) positioner on straight-bar top, (3) are fixed on for fixing in straight-bar, (2) The horizonal base plate of straight-bar, (4) are fixed on the inclinometer of straight-bar tail end.

8. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as described in right will go 7, it is characterised in that institute It is the infrared positioning bead that can be recognized by the infrared monitoring equipment to state positioner.

9. the method for putting position is calibrated by human projection in a kind of radiotherapy operation as claimed in claim 1, it is characterised in that institute The step of deviation for calculating human body side outline projection under Two coordinate system is stated to adjust patient location includes：S9：Computer is by S5 Calculate obtained transition matrix and act on projection B, it is transferred under projection A coordinate system, calculate the deviation between two projections And correspondingly adjust the position of patient.S10：Repeating said steps S6~S9 is until deviation is in certain threshold value.