CN111773561B - Flat panel detector position offset detection method and radiotherapy device - Google Patents

Abstract

The invention discloses a flat panel detector position offset detection tool, a flat panel detector position offset detection method and a radiotherapy device, wherein the detection tool comprises: the base plate is used for being fixed on the flat panel detector, the plurality of stand columns are fixed on the testing surface of the base plate, and the plurality of stand columns are uniformly distributed on the testing surface. According to the invention, the position offset of the flat panel detector relative to the radioactive source can be detected when the radiotherapy device frame is at different angles without the aid of a high-precision measuring tool, so that the position offset of the flat panel detector can be quickly obtained, and the detection tool has the advantages of simple structure, convenience in installation, simple detection method steps and convenience in operation.

Description

Flat panel detector position offset detection method and radiotherapy device

technical field

The invention belongs to the field of medical technology, and in particular relates to a flat panel detector position offset detection tool, a method and a radiation therapy device.

Background technique

As shown in Figure 2, modern radiotherapy equipment is usually equipped with a flat panel detector, and the detector is used for electronic portal imaging as a direct basis for whether the patient is positioned correctly, and the flat panel detector is also used for some daily mechanical Performance testing. The flat panel detector is fixed by a special support arm, and the support arm moves and fixes the flat panel in a special position as needed. Whether the position of the flat panel detector is accurate becomes a very important reference parameter. If the reference position If it is inaccurate, the basis for the detection of the mechanical properties of the radiotherapy device based on the flat panel detector will be inaccurate, resulting in the unreliability of the entire detection.

The detection of the positioning accuracy of the flat panel detector in the existing technology is carried out by means of high-precision ranging sensors or level meters, and the whole process cannot be completed automatically, requiring a lot of energy and material resources for measurement and verification.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a flat panel detector position offset detection tool, method and radiation therapy device.

In order to achieve the above object, technical scheme of the present invention is as follows:

In one aspect, the present invention discloses a position offset detection tool for a flat panel detector, comprising:

The base plate, the base plate is used to be fixed on the flat panel detector;

For the uprights, N uprights are fixed on the test surface of the substrate, and the N uprights are evenly distributed on the test surface, and N≥2.

On the basis of the above technical solutions, the following improvements can be made:

As a preferred solution, the N uprights are symmetrically arranged at the center of the test surface of the substrate, wherein N is an even number.

As a preferred solution, the thickness of the substrate is 2-3 mm, and the column is a cylinder with a diameter of 1 mm and a height of 5-10 cm.

As a preferred solution, the base plate is an aluminum plate or a carbon fiber plate, and the column is a tungsten column or a copper column.

On the other hand, the present invention also discloses a method for detecting the position offset of a flat panel detector, which specifically includes the following steps:

S1: Fix the detection tool on the upper surface of the flat panel detector;

S2: After fixing the detection tool, turn the rotating gantry of the radiotherapy device to 0°, and start the radiation source to collect images of the electron field. At this time, there are N column images on the obtained electron images, and record the N images at this time. The position of the column image in the entire imaging area of the flat panel detector is used as a reference image for judging the position of the flat panel detector;

S3: Rotate the rotating gantry of the radiotherapy device at a certain angle, start the radiation source again for electronic imaging, and compare the image obtained at this time with the image obtained by the detection tool on the flat panel detector with the image obtained at the 0° position, so as to detect Whether the position of the flat panel detector is offset relative to the ray source, if there is a position offset, the actual position offset of the flat panel detector is calculated according to the offset of the column image.

As a preferred solution, step S3 specifically includes the following contents: turn the rotating gantry of the radiotherapy device to the 90° position, the 180° position and the 270° position respectively, start the ray source at each position to perform electronic imaging, put each The image obtained from the position of the detection tool on the flat panel detector is compared with the image obtained at the 0° position, so as to detect whether the flat panel detector at this position has a position offset relative to the ray source. Image Offset Calculates the actual flat panel detector position offset.

As a preferred solution, when the rotating gantry of the radiotherapy device is rotated to the 90° position or the 270° position, the following method is used to calculate the actual position offset of the flat panel detector:

According to the size of each pixel of the flat panel detector, how many pixels are occupied by the column image, so as to calculate the size of the column image;

Compare the image of the inspection tool on the flat panel detector obtained at the 90° position or 270° position with the image obtained at the 0° position,

If the image size of the upper column is the same as the image size of the lower column, there is no positional offset of the flat panel detector in the vertical direction;

If the size of the upper column image and the lower column image are not the same, the flat panel detector has a position offset in the vertical direction, and the size difference of the column image is obtained according to the compared image difference. Since the size of the column image is known, it can be obtained the actual flat panel detector offset,

Or, perform the offset calibration of the flat panel detector in advance, set the offset of the flat panel detector to a fixed number of x mm, x=1, 2,...n, perform electronic imaging, and record the column when the offset of the flat panel detector is different. The difference of the image is used as a reference value, and the difference of the actual column image is compared with the reference value to obtain the actual offset of the flat panel detector.

As a preferred solution, the offset of the flat panel detector is calibrated in advance, and the offset of the flat panel detector is set to a fixed number of x mm, x=1,2,...n, and electronic imaging is performed to record the different offsets of the flat panel detector. The difference of the column image when measuring is used as the reference value, and the actual difference of the column image obtained is compared with the reference value to obtain the actual offset of the flat panel detector;

When the actual offset is non-integer, it is obtained by interpolation.

As a preferred solution, when the rotating gantry of the radiotherapy device is rotated to the 180° position, the following method is used to calculate the actual position offset of the flat panel detector:

According to the size of each pixel of the flat panel detector, how many pixels are occupied by the column image, so as to calculate the size of the column image;

Compare the image obtained by the inspection tool at the 180° position on the flat panel detector with the image obtained at the 0° position,

If the distance between the flat panel detector and the ray source remains unchanged, and the image size of the column remains unchanged, there is no positional shift of the flat panel detector;

If the distance between the flat panel detector and the ray source becomes shorter, or the size of the column image becomes larger, the position of the flat panel detector is shifted, and the size difference of the column image is obtained according to the compared image difference. Since the size of the column image is known, The actual offset of the flat panel detector can be obtained,

Or, perform the offset calibration of the flat panel detector in advance, set the offset of the flat panel detector to a fixed number of x mm, x=1, 2,...n, perform electronic imaging, and record the column when the offset of the flat panel detector is different. The difference of the image is used as a reference value, and the difference of the actual column image is compared with the reference value to obtain the actual offset of the flat panel detector.

In addition, the present invention also discloses a radiotherapy device, which includes a flat panel detector position offset detection tool; or, the radiotherapy device is used for implementing a flat panel detector position offset detection method.

The invention solves the problems in the prior art that the detection of the positioning accuracy of the plate support arm requires the use of high-precision ranging tools and level instruments, and the process is cumbersome and difficult to operate. The present invention provides a tool for detecting the position offset of a flat panel detector, a method and a radiotherapy device, which can detect the difference between the flat panel detector and the radiation source when the frame of the radiotherapy device is at different angles without the aid of a high-precision measuring tool. For position offset, it is only necessary to tightly fix the inspection tool and the flat panel detector, and then perform electronic portal imaging at different angles. According to the obtained electronic image, with the corresponding image processing algorithm, the position offset of the flat panel detector can be quickly obtained. The detection tooling has simple structure, convenient installation, simple detection method steps and convenient operation.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a tool for detecting a position offset of a flat panel detector according to an embodiment of the present invention.

FIG. 2 is a front view of a radiotherapy apparatus provided in the prior art.

FIG. 3 is a front view of a radiotherapy apparatus provided by an embodiment of the present invention.

FIG. 4 is a schematic diagram of a flat panel detector with a rack at a position of 0° according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a flat panel detector at a 90° position of a rack provided by an embodiment of the present invention.

FIG. 6 is a schematic diagram of a flat panel detector at 180 o'clock position of a rack provided by an embodiment of the present invention.

FIG. 7 is a schematic diagram of a flat panel detector at a 270° position of a rack provided by an embodiment of the present invention.

FIG. 8 is a schematic diagram of the deflection of the flat panel detector when the rack provided by the embodiment of the present invention is at a position of 90°.

FIG. 9 is a schematic diagram of the deflection of the flat panel detector when the rack provided by the embodiment of the present invention is at a position of 270°.

FIG. 10 is a schematic diagram of the deflection of the flat panel detector when the rack provided by the embodiment of the present invention is at a position of 180°.

FIG. 11 is a flowchart of a method for detecting a position offset of a flat panel detector according to an embodiment of the present invention.

1- detection tooling, 11- base plate, 12- column, 2- radiotherapy device, 21- flat panel detector, 22- rack, 23- ray source, 24- detector bracket, 25- radiation field.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

On the one hand, an embodiment of the present invention discloses a flat panel detector position offset detection tool, as shown in FIG. 1 , including:

The base plate 11, the base plate 11 is used to be fixed on the flat panel detector 21;

For the uprights 12, four uprights 12 are fixed on the test surface of the substrate 11, and the four uprights 12 are evenly distributed on the test surface.

The inspection tooling is simple in structure and convenient in installation. The number of the uprights 12 can be 6, 8, 10 or the like.

In order to further optimize the implementation effect of the present invention, in other embodiments, other features and techniques are the same, the difference is that the four uprights 12 are symmetrically arranged with respect to the center of the test surface of the substrate 11 .

In order to further optimize the implementation effect of the present invention, in other embodiments, the remaining features and techniques are the same, except that the thickness of the substrate 11 is 2-3 mm, the column 12 is 1 mm in diameter and 5-10 cm in height cylinder.

Of course, in other embodiments, the thickness and size of the substrate 11 can be adaptively adjusted according to the size of the specific flat panel detector 21 , and the size and shape of the uprights 12 are not limited.

In order to further optimize the implementation effect of the present invention, in other embodiments, other features and techniques are the same, the difference is that the substrate 11 is an aluminum plate or a carbon fiber plate, and the column 12 is a tungsten column or a copper column.

Of course, in other embodiments, the base plate 11 of the inspection tool is not limited to an aluminum plate and a carbon fiber plate, and it can also be a plate made of other high-strength and high-ray transmittance materials. For example, carbon fiber board, etc., the pillars 12 are not limited to tungsten pillars and copper pillars, and can also be other high-density metal pillars.

On the other hand, the embodiment of the present invention also discloses a method for detecting the position offset of the flat panel detector 21, as shown in FIG. 11, which specifically includes the following steps:

S1: Fix the detection tool 1 on the upper surface of the flat panel detector 21;

S2: After fixing the detection tool, turn the rotating gantry 22 of the radiotherapy device 2 to 0°, as shown in FIG. 4 , start the radiation source 23 to collect images of the electron field. At this time, there are 4 record the positions of the four column images in the entire imaging area of the flat panel detector 21 respectively, as a reference image for judging the position of the flat panel detector 21;

S3: Rotate the rotating gantry 22 of the radiotherapy device 2 by a certain angle, start the radiation source again to perform electronic imaging, and compare the image obtained at this time with the image obtained by the detection tool on the flat panel detector 21 and the image obtained at the 0° position, Thereby, it is detected whether the flat panel detector 21 has a position offset relative to the radiation source 23 , and if there is a position offset, the actual position offset of the flat panel detector 21 is calculated according to the column image offset.

The flat panel detector 21 is supported by the detector bracket 24, and the radiation field 25 of the radiation source 23 is shown in the figure.

In order to further optimize the implementation effect of the present invention, in other embodiments, other features and technologies are the same, the difference is that step S3 specifically includes the following content: turning the rotating gantry 22 of the radiotherapy device 2 to 90° respectively position (as shown in Fig. 5), 180° position (as shown in Fig. 6) and 270° position (as shown in Fig. 7), the radiation source 23 is activated at each position to perform electronic imaging, and the detection obtained at each position The image of the tool mounted on the flat panel detector 21 is compared with the image obtained at the 0° position, so as to detect whether the flat panel detector 21 has a position offset relative to the radiation source 23 at this position. The offset calculates the actual position offset of the flat panel detector 21 .

Further, on the basis of the above-mentioned embodiment, when the rotating gantry 22 of the radiotherapy apparatus 2 is rotated to the 90° position or the 270° position, the following method is used to calculate the actual position offset of the flat panel detector 21:

According to the size of each pixel of the flat panel detector 21, how many pixels are occupied by the column image, thereby calculating the size of the column image;

As shown in Figures 8 and 9 (wherein, the solid line represents the 0° position image, and the dotted line represents the shifted position image), the detection tool obtained at the 90° position or the 270° position is mounted on the flat panel detector 21. The image is compared with the image obtained at the 0° position,

If the image size of the upper column is the same as that of the lower column, the flat panel detector 21 has no positional offset in the vertical direction;

If the size of the upper column image is different from that of the lower column image, the flat panel detector 21 is displaced in the vertical direction, and the size difference of the column image is obtained according to the compared image difference. Since the size of the column image is known, according to the figure The geometric relationship of the actual flat panel detector 21 offset can be obtained,

Or, calibrate the offset of the flat panel detector 21 in advance, set the offset of the flat panel detector 21 to a fixed number of 1 mm, 2 mm, 3 mm, etc. for electronic imaging, and record the column when the flat panel detector 21 has different offsets. The difference of the images is used as a reference value, and the difference of the actual column image is compared with the reference value to obtain the actual offset of the flat panel detector 21. When the actual offset is a non-integer, it can be obtained by interpolation.

Further, on the basis of the above-mentioned embodiment, when the rotating gantry 22 of the radiotherapy device 2 is rotated to the 180° position, the following method is used to calculate the positional offset of the actual flat panel detector 21:

According to the size of each pixel of the flat panel detector 21, how many pixels are occupied by the column image, thereby calculating the size of the column image;

As shown in Fig. 10 (wherein, the solid line represents the 0° position image, and the dotted line represents the shifted position image), when the image of the detection tool obtained at the 180° position is placed on the flat panel detector 21 and the 0° position The obtained images are compared,

If the distance between the flat panel detector 21 and the radiation source 23 is unchanged, and the size of the column image is unchanged, the flat panel detector 21 has no positional offset;

If the distance between the flat panel detector 21 and the radiation source 23 becomes shorter, or the size of the column image becomes larger, the position of the flat panel detector 21 is shifted, and the size difference of the column image is obtained according to the compared image difference. Image size, the actual offset of the flat panel detector 21 can be obtained according to the geometric relationship shown in the figure,

Or, calibrate the offset of the flat panel detector 21 in advance, set the offset of the flat panel detector 21 to a fixed number of 1 mm, 2 mm, 3 mm, etc. for electronic imaging, and record the column when the flat panel detector 21 has different offsets. The difference of the images is used as a reference value, and the difference of the actually obtained column image is compared with the reference value to obtain the actual offset of the flat panel detector 21 .

In addition, as shown in FIG. 3 , the present invention also discloses a radiotherapy device 2 , the radiotherapy device 2 includes a flat panel detector position offset detection tool; or, the radiotherapy device 2 is used for detecting the position offset of the flat panel detector 21 . method.

The invention solves the problems in the prior art that the detection of the positioning accuracy of the plate support arm requires the use of high-precision ranging tools and level instruments, and the process is cumbersome and difficult to operate. The present invention provides a flat panel detector position offset detection tool, method and radiotherapy device, which can detect the relative position of the flat panel detector 21 relative to the radiotherapy device 2 when the frame 22 is at different angles without the aid of a high-precision measuring tool. If the position of the radiation source is shifted, it is only necessary to fix the detection tool and the flat panel detector 21 tightly, and then carry out electronic portal imaging at different angles. According to the obtained electronic image and the corresponding image processing algorithm, the flat panel detector can be quickly obtained. The position offset of 21, the detection tooling has a simple structure, convenient installation, simple detection method steps, and convenient operation.

The above multiple implementations can be implemented in parallel in an interleaved manner.

The above-mentioned embodiments are only for illustrating the technical concept and characteristics of the present invention, and their purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement them, and cannot limit the scope of protection of the present invention with this. Equivalent changes or modifications made should be covered within the protection scope of the present invention.

Claims (8)

1. A method for detecting position offset of a flat panel detector, characterized in that it specifically comprises the following steps: S1: The flat panel detector position offset detection tool is fixedly installed on the upper surface of the flat panel detector. The flat panel detector position offset detection tool includes: a base plate and a column, and the base plate is used to be fixed on the flat panel detector. , N number of uprights are fixed on the test surface of the substrate, and the N number of the uprights are evenly distributed on the test surface, N≥2; S2: After fixing the detection tool, turn the rotating gantry of the radiotherapy device to 0°, and start the radiation source to collect images of the electron field. At this time, there are N column images on the obtained electron images, and record the N images at this time. The position of the column image in the entire imaging area of the flat panel detector is used as a reference image for judging the position of the flat panel detector; S3: Turn the rotating gantry of the radiotherapy device to the 90° position, 180° position and 270° position respectively, start the radiation source at each position for electronic imaging, and install the detection tool obtained at each position on the flat panel detector. The image is compared with the image obtained at the 0° position, so as to detect whether the position of the flat panel detector is offset relative to the ray source. shift. 2. The method for detecting the position offset of a flat panel detector according to claim 1, wherein when the rotating gantry of the radiotherapy device is turned to a 90° position or a 270° position, the following method is used to calculate the actual flat panel detector position Offset: According to the size of each pixel of the flat panel detector, how many pixels are occupied by the column image, so as to calculate the size of the column image; Compare the image of the inspection tool on the flat panel detector obtained at the 90° position or 270° position with the image obtained at the 0° position, If the image size of the upper column is the same as the image size of the lower column, there is no positional offset of the flat panel detector in the vertical direction; If the size of the upper column image and the lower column image are not the same, the flat panel detector has a positional offset in the vertical direction, and the size difference of the column image is obtained according to the compared image difference. Since the size of the column image is known, it can be obtained the actual flat panel detector offset, Or, perform the offset calibration of the flat panel detector in advance, set the offset of the flat panel detector to a fixed number of x mm, x=1, 2,...n, perform electronic imaging, and record the column when the flat panel detector has different offsets The difference of the image is used as a reference value, and the difference of the actual column image is compared with the reference value to obtain the actual offset of the flat panel detector. 3. The method for detecting the position offset of a flat panel detector according to claim 2, wherein the offset of the flat panel detector is calibrated in advance, and the offset of the flat panel detector is set to a fixed number of x millimeters, x= 1,2,...n, perform electronic imaging, record the difference of the column image with different offsets of the flat panel detector as a reference value, compare the difference between the actual obtained column image and the reference value, and obtain the actual offset of the flat panel detector quantity; When the actual offset is non-integer, it is obtained by interpolation. 4. The flat-panel detector position offset detection method according to claim 1, wherein when the rotating gantry of the radiotherapy device turns to the 180° position, the following method is used to calculate the actual flat-panel detector position offset: According to the size of each pixel of the flat panel detector, how many pixels are occupied by the column image, so as to calculate the size of the column image; Compare the image obtained by the inspection tool at the 180° position on the flat panel detector with the image obtained at the 0° position, If the distance between the flat panel detector and the ray source is unchanged, and the size of the column image is unchanged, there is no positional offset of the flat panel detector; If the distance between the flat panel detector and the ray source becomes shorter, or the size of the column image becomes larger, the position of the flat panel detector is shifted, and the size difference of the column image is obtained according to the compared image difference. Since the size of the column image is known, The actual offset of the flat panel detector can be obtained, Or, perform the offset calibration of the flat panel detector in advance, set the offset of the flat panel detector to a fixed number of x mm, x=1, 2,...n, perform electronic imaging, and record the column when the flat panel detector has different offsets The difference of the image is used as a reference value, and the difference of the actual column image is compared with the reference value to obtain the actual offset of the flat panel detector. 5 . The method for detecting position offset of a flat panel detector according to claim 1 , wherein the N uprights are symmetrically arranged with respect to the center of the test surface of the substrate, wherein N is an even number. 6 . 6 . The method for detecting position offset of a flat panel detector according to claim 1 , wherein the thickness of the substrate is 2-3 mm, and the column is a cylinder with a diameter of 1 cm and a height of 5-10 cm. 7 . . 7 . The method for detecting position offset of a flat panel detector according to claim 1 , wherein the base plate is an aluminum plate or a carbon fiber plate, and the upright column is a tungsten column or a copper column. 8 . 8 . The radiotherapy apparatus, characterized in that, the radiotherapy apparatus is used to implement the method for detecting the position offset of the flat panel detector according to any one of claims 1 to 7 .

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