CN113975660A - Method and equipment for monitoring displacement of tumor target area - Google Patents

Method and equipment for monitoring displacement of tumor target area Download PDF

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CN113975660A
CN113975660A CN202111279965.5A CN202111279965A CN113975660A CN 113975660 A CN113975660 A CN 113975660A CN 202111279965 A CN202111279965 A CN 202111279965A CN 113975660 A CN113975660 A CN 113975660A
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marker
image
displacement
tumor
ellipse
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CN113975660B (en
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侯再红
王妍璐
何枫
程乙轮
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Hefei Institutes of Physical Science of CAS
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    • A61N2005/1096—Elements inserted into the radiation path placed on the patient, e.g. bags, bolus, compensators
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    • G06T2207/10—Image acquisition modality
    • G06T2207/10072—Tomographic images
    • G06T2207/10081—Computed x-ray tomography [CT]
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Abstract

The invention provides a method and equipment for monitoring displacement of a tumor target area, wherein the method comprises the following steps: step S1: setting a treatment point on the thermoplastic film, wherein the treatment point is a position irradiated by radiotherapy rays; positioning a marker, wherein the position of the marker corresponds to the target region of the tumor; step S2: and calculating the displacement value of the tumor target area according to the relative displacement of the marker and the treatment point. The invention can realize the real-time monitoring of the displacement of the tumor target area when a certain moving space is formed between the thermoplastic film and the patient.

Description

Method and equipment for monitoring displacement of tumor target area
Technical Field
The invention relates to the technical field of heavy ion radiotherapy, in particular to a method and equipment for monitoring displacement of a tumor target area.
Background
In cancer treatment, heavy ion radiotherapy is adopted because of high cure rate and humanization, and is rapidly popularized. 70% of patients with tumors need to receive radiation therapy (hereinafter referred to as radiotherapy) at various stages of tumor development. In traditional radiotherapy flow, at first through the internal tumour target area position of CT scanning location patient, later cover the thermoplastic film of customized to one's body at the patient body surface to set up the position that the mark point marked the tumour on thermoplastic film according to CT scanning result, radiotherapy ray aims the mark point on the thermoplastic film and carries out the radiotherapy to the patient at last among the radiotherapy process.
However, because the time period of the radiotherapy is long, the patient's body shape can change significantly during the radiotherapy process, so that the patient has a certain movement space under the thermoplastic film, and a certain error can occur by using the method of setting the marking point on the thermoplastic film to mark the position of the tumor. When heavy ion rays are irradiated on healthy tissues, not only the treatment effect is reduced, but also additional side effects are brought to the patient. Research shows that the position of a patient deviates 5mm in the radiotherapy process, and the radiotherapy curative effect is reduced by 18.4%; the effect of a deviation of 6mm is reduced by 33.4%. When the offset is larger, the damage to healthy tissue is greater than the treatment of the tumor. There is therefore a need for a method or apparatus to address the problem of monitoring the displacement of a target region of a patient's tumor during radiotherapy.
Disclosure of Invention
Aiming at the defects in the background technology, the invention discloses a method for monitoring the displacement of a tumor target area,
the method comprises the following steps:
step S1: setting a treatment point on the thermoplastic film, wherein the treatment point is a position irradiated by radiotherapy rays; positioning a marker, wherein the position of the marker corresponds to the target region of the tumor;
step S2: and calculating the displacement value of the tumor target area according to the relative displacement of the marker and the treatment point.
Preferably, the step of locating the marker comprises:
SA101, extracting feature points on the physical feature markers;
and SA102, matching the characteristic points in the real-time image and the reference image by adopting a characteristic point matching algorithm, and calculating the displacement of the characteristic points to position the marker.
Preferably, the marker is a geometric marker;
the step of locating the marker comprises:
SA111, segmenting the marker and the background;
SA112, marking the marker outline by adopting a fitting algorithm;
and SA113, determining the geometric center position of the marker, and positioning the marker.
Preferably, wherein the color of the marker is one of three primary colors;
step SA111 specifically includes the following steps:
SA1111, splitting the collected color image into three gray level images of three channels of red, green and blue;
SA1112 subtracts the gray value of the pixel in the image corresponding to the color channel of the marker from the gray value of the pixel corresponding to the other two channels.
Preferably, the step SA112 specifically includes:
SA 1121: calculating the outline of the gray level image containing the marker by using a Canny algorithm;
SA 1122: eliminating the contours with the areas smaller than a set threshold value in the contours;
SA 1123: and solving convex hulls from all the contours of each marker, and calculating to obtain the outer contour of the marker.
Preferably, step SA113 specifically includes the steps of:
SA 1131: extracting points on the outer contour of the marker;
SA 1132: fitting an ellipse by adopting a least square method;
SA 1133: calculating the distances from all the fitting points to the center of the fitting ellipse, and eliminating noise points with abnormal distances by adopting a Grabbs criterion;
SA 1134: fitting the ellipse by adopting a least square method again;
SA 1135: judging whether a noise point is contained; if the noise point is included, the process goes back to step SA1133, and if the noise point is not present, the marker is located by the center of the ellipse.
Preferably, the method further comprises step SA 1136: and taking the center of the ellipse as a center, and taking a rectangular area with the length and the width being preset multiples of the elliptical axis as an interested area of the next frame image, wherein the interested area represents that the subsequent image is only subjected to ellipse fitting in the interested area.
In another embodiment of the present invention, a tumor target displacement monitoring apparatus is further disclosed, the apparatus comprising:
an image acquisition unit for acquiring an image, wherein the image acquisition unit is coaxially mounted with a small divergence angle annular light source and handles with the marker setting;
the marker is used for positioning the tumor position, wherein a microprism reflective membrane is attached to the surface of the marker;
and the image processing unit is used for processing and calculating the image to obtain the displacement information of the target area of the tumor.
In another embodiment of the present invention, a computer-readable storage medium is further disclosed, on which a computer program is stored, the computer program being executed to perform any one of the methods for monitoring displacement of a target region of a tumor.
In another embodiment of the present invention, a computer device is further disclosed, which includes a processor, a storage medium, and a computer program stored on the storage medium, wherein the processor reads and executes the computer program from the storage medium to perform any one of the tumor target displacement monitoring methods.
Has the advantages that:
(1) through set up the treatment point on thermoplastic film and set up the marker that corresponds in real time with tumour target area position, calculate the displacement value of tumour target area in real time according to the relative displacement of treatment point and marker, realize the monitoring to tumour target area displacement, improve the radiotherapy effect.
(2) The marker points on the extracted marker can be positioned according to the displacement of the marker points.
(3) After the marker and the background are cut, the marker contour can be more accurately fitted.
(4) The step of color space conversion is omitted, and the selection of each component threshold value under different illumination conditions is not required to be considered.
(5) Rejecting contours with a contour less than a set threshold can improve the accuracy of locating the marker.
(6) The three-dimensional condition of the human body is considered, noise points are removed, and the positioning accuracy is improved.
(7) Considering that the patient displacement is small with the thermoplastic film fixed, the area for acquiring the image is limited, so that the positioning is more accurate and rapid.
Drawings
FIG. 1 is a flow chart of a method for monitoring displacement of a target region of a tumor according to an embodiment of the present invention;
FIG. 2 is a flow chart of locating a marker in accordance with an embodiment of the present invention;
FIG. 3 is a flow chart of fitting markers and obtaining the center position of the markers for localization in an embodiment of the present invention;
FIG. 4 is a schematic diagram of the operation of a tumor target displacement monitoring device according to an embodiment of the present invention;
FIG. 5a is a schematic view of the path of light from the ring light source when the marker is attached with the microprism reflective film in accordance with embodiments of the present invention;
FIG. 5b is a schematic view of the light path emitted by the ring light source when the marker is diffusely reflected;
FIG. 6 is a distribution diagram of markers in an embodiment of the present invention;
FIG. 7a is a schematic view of positioning a marker under a thermoplastic film when the marker is X-corner shaped;
FIG. 7b is a schematic view of positioning a marker under a thermoplastic film when the marker is rectangular;
FIG. 7c is a schematic view of positioning a marker under a thermoplastic film when the marker is circular.
In the figure: 1. an industrial camera; 2. a marker; 21. a microprism light-reflecting film; 3. a patient's membrane; 4. an annular light source; 5. and (4) a bracket.
Detailed Description
In order to solve the above problems, an embodiment of the present invention discloses a method for monitoring displacement of a tumor target region, specifically, after scanning a tumor position in a patient body through CT, a marker is fixed at the tumor position on the body surface of the patient, and a treatment point is set on a thermoplastic film, wherein when radiotherapy is performed for the first time, the treatment point is located at the same position as the marker, and both the treatment point and the marker correspond to the tumor position in the patient body. When next radiotherapy is carried out, because the body shape or the posture of the patient changes, the body surface position of the patient corresponding to the treatment point can deviate, and the position of the treatment point does not correspond to the tumor position in the patient. Since the markers are fixed on the body surface of the patient, the positions of the markers change along with the change of the body shape of the patient, and the positions of the markers still correspond to the positions of the tumors in the body of the patient at the next radiotherapy. The air holes arranged on the thermoplastic film can position the marker, and the displacement of the tumor target area can be accurately calculated according to the relative displacement of the marker and the treatment point, so as to obtain a new treatment point. Namely, the tumor position in the patient body can be accurately positioned according to the marker without carrying out CT scanning again and customizing a new thermoplastic film by measuring the body again. From the above, the invention can better solve the problem that the therapy point deviates from the tumor position in the patient body due to the change of the patient body shape, and the therapy position can be adjusted at the first time if the patient moves in the thermoplastic film during the therapy.
The invention will be described in detail below with reference to the drawings, as shown in fig. 1.
Step S1: setting a treatment point on the thermoplastic film, wherein the treatment point is a position irradiated by radiotherapy rays; markers are located, wherein the marker locations correspond to the tumor target area.
Specifically, in order to avoid the patient position to remove when carrying out the radiotherapy, adopt the thermoplastic film to fix the position of patient. The thermoplastic film is formed at one time according to the body shape of a patient, and cannot be adjusted at the later stage. In order to determine the position of the target area of the tumor, a treatment point is arranged on the thermoplastic film, and during radiotherapy, radioactive rays are emitted aiming at the position of the treatment point so as to inactivate the cancer cells in the patient. The position represented by the treatment point at the first treatment is the position of the target area of the tumor. Since the patient does not always remain in a relatively static state during the treatment, dynamic adjustments to the treatment point are required.
Illustratively, the markers are affixed to the patient's body surface, for example, the markers may be affixed to the patient's body surface. The position of which corresponds to the position of the tumor in the patient, i.e. the target region of the tumor. When the body shape or posture of the patient changes, the position of the marker fixed on the body surface of the patient moves along with the change, and the position corresponding to the marker is still the tumor position in the body of the patient. The marker is fixed on the body surface of the patient and covered by the thermoplastic film, and can not be observed by naked eyes, and partial information of the marker can be observed only through the air holes on the thermoplastic film. Therefore, it is important to accurately position the markers, and the positioning related content of the markers will be described in detail in other embodiments of the present invention.
Step S2: and calculating the displacement value of the tumor target area according to the relative displacement of the marker and the treatment point.
Specifically, the position irradiated by the radiotherapy radiation is positioned according to the relative displacement of the marker in the treatment process, the position of the treatment starting point is taken as the initial position, and the relative displacement of the marker and the treatment point in the treatment process is taken as a deviation area to adjust the position of the treatment point, namely the irradiation position of the radioactive ray.
Illustratively, the position of the markers changes when the patient's body shape or posture changes, but the treatment site on the thermoplastic film does not change. Therefore, when the body shape of the patient changes, the markers are positioned, then the relative displacement of the original markers and the treatment points is calculated, the displacement value of the tumor target area relative to the original treatment points can be obtained, the position of the treatment points is simply changed according to the displacement value after the displacement value is obtained, the tumor target area is accurately positioned, and the tumor cells in the body of the patient are accurately hit. For example, the original treatment point is used as the origin of coordinates, and the coordinates after the marker displacement are (X, Y). Then during the subsequent radiotherapy procedure, the point (X, Y) is treated. In the actual treatment process, the tumor target area is an area, and in the subsequent treatment process, the shape of the area of the tumor target area is kept unchanged, wherein the point (X, Y) can be the central point of the tumor target area or any point in the tumor target area, and the relative position in the tumor target area of the point (X, Y) in the previous and subsequent treatment processes is only required to be kept unchanged.
In another embodiment of the invention the markers are geometric markers; as shown in fig. 2, the positioning the marker includes:
step SA 111: segmenting the marker and the background;
step SA 112: adopting a fitting algorithm to mark the contour;
step SA 113: and determining the geometric center position of the marker, and positioning the marker.
Specifically, since the marker is mostly shielded by the thermoplastic film during the radiotherapy, the complete marker cannot be observed by optical tracking, and a small part of the marker profile leaks out from the ventilation holes of the thermoplastic film. Therefore, the marker contour needs to be separated from the background so as to locate the marker.
In the present embodiment, the color characteristics of the markers are used for segmentation. The color of the marker adopts one of three primary colors, and the method specifically comprises the following steps:
SA 1111: splitting the collected color image into three gray level images of red, green and blue channels respectively;
SA 1112: the gray values of the pixels corresponding to the other two channels are subtracted from the gray value of the pixel corresponding to the color channel passing through the marker in the image.
It is worth explaining that since the color image captured by an industrial camera is generally an RGB image, the RGB color space describes the color by describing the proportion of red, green and blue in the color by R, G, B three components. The value ranges of the brightness values of the three components are all 0-255, and the larger the value is, the higher the proportion of the color component in the pixel point is. For example, the marker adopts blue of one of three primary colors, and after the collected color image is split into three grayscale images of three channels of red, green and blue, respectively, the image background only contains white and skin color, and the target object is blue. The red component and the blue component in white are the same, the skin color of different races is mainly the brightness difference, the chromaticity difference of skin color is not large, the red component is larger than the blue component, and the blue component of the blue marker is far larger than the red component. Therefore, in the gray-scale image of the blue channel, the brightness value of the marker is obviously higher, so that the background mottle can be removed by subtracting the gray-scale value of the pixel corresponding to the red channel and the green channel from the gray-scale value of the pixel corresponding to the blue channel in the color image. Compared with the common target segmentation in the HSV color space, the method makes full use of the color characteristics of the background in the radiotherapy monitoring range, omits the step of color space conversion, and does not need to consider the selection of each component threshold under different illumination conditions.
And obtaining a gray image which only contains the markers after the background is removed. Fitting a localization marker requires points on the outer contour of the marker, and therefore after separating the marker, it is also necessary to extract the points on the outer contour of the marker. Specifically, the step S22 specifically includes the following steps:
step SA 1121: : calculating the outline of the gray level image containing the marker by using a Canny algorithm;
step SA 1122: eliminating the contours with the areas smaller than a set threshold value in the contours;
step SA 1123: and solving convex hulls from all the contours of each marker, and calculating to obtain the outer contour of the marker.
Noise points in the marker segmented image can be removed by step SA 1122. The contour obtained at this time is not the contour of the outermost layer of the marker, but a plurality of small contours formed after the marker is covered by the thermoplastic film, a convex hull needs to be obtained for all contours of each marker, the convex hull of the contour of the marker is obtained by using the Graham scanning algorithm in step SA1123, and the vertex of the convex hull is a point on the outer contour of the marker. The time consumption of the Graham scanning algorithm is positively correlated with the number N of the contour points, the larger the N is, the longer the algorithm time consumption is, so that the time consumption of the algorithm can be reduced by designing the marker into a circular ring, and the real-time performance is better ensured.
Because the positioning marker only needs the outer contour information of the marker, in order to reduce the calculation amount when positioning the marker, the information of the middle part of the marker is omitted in another embodiment of the invention. Extracting the contour of the marker, then obtaining the shape of the marker by adopting a fitting algorithm, then determining the geometric center position of the marker, and positioning the marker to obtain the position of the tumor target area.
Illustratively, in this embodiment the markers are circular ring markers and the ring width of the circular ring markers is not less than the blocking portion between the thermoplastic film apertures. For example, as shown in fig. 6, the width of the shielding part between the small holes of the general medical thermoplastic film is 2mm, the ring width of the circular ring markers can be set to 3mm, so that part of the markers can be ensured to leak all the time, the positioning failure of the markers due to the shielding of the markers can be avoided, and a plurality of circular ring markers are arranged in a matrix of 90mm by 90 mm. Illustratively, the circular ring marker is a circular ring formed by a circle with a diameter of 3mm, and the position of the circle can be determined by knowing three points on the circle according to mathematical knowledge, namely, the position of the marker can be determined by only finding three points on the marker on the thermoplastic film. Compared with the rectangular marker, the method has the advantages that the specific position of the marker can be located by locating four sides, and the position of the marker is more conveniently located. As can be seen from fig. 7a, 7b and 7c, the markers at the X-corner points cannot be positioned by the thermoplastic film, and when the two parallel sides of the rectangle are blocked, the rectangles at three different positions in the figure have the same exposed outline, i.e. the only rectangular marker cannot be recovered from the outline of the rectangle, so that the markers cannot be accurately positioned. Only the circular (or circular ring) marker can determine a uniquely determined circle from only three points, so that designing the marker to be circular (or circular ring) can minimize the influence of thermoplastic film shielding on the positioning of the marker. It is noted that the solid circles in fig. 7a, 7b and 7c are ventilation holes of the thermoplastic film and the dotted lines represent the outline of the logo under the thermoplastic film.
In another embodiment of the present disclosure, the step of locating the marker comprises:
SA101, extracting feature points on the physical feature markers;
and SA102, matching the characteristic points in the real-time image and the reference image by adopting a characteristic point matching algorithm, and calculating the displacement of the characteristic points to position the marker.
Specifically, the markers have obvious physical characteristics, and when the markers are positioned, characteristic points on the markers are extracted. Illustratively, a Harris corner detection algorithm is adopted for extracting the characteristic points of the marker, and after the characteristic points are extracted, a characteristic point matching algorithm is adopted for matching the characteristic points in the real-time image and the reference image to calculate the displacement of the characteristic points, so that the marker is positioned. For example, a feature point a exists on the marker, and the feature point a is located on a specific part of the marker. When the characteristic point is monitored, the characteristic point A is monitored, and the shape of the marker is known, so that the displacement passing through the characteristic point A is the displacement of the marker, and the marker can be positioned according to the displacement of the marker.
In another embodiment of the present invention, a specific step of locating the geometric center of a marker and positioning the marker is disclosed, which is specifically shown in fig. 3:
step SA 1131: extracting points on the outer contour of the marker;
step SA 1132: fitting an ellipse by adopting a least square method;
step SA 1133: calculating the distances from all the fitting points to the center of the fitting ellipse, and eliminating noise points with abnormal distances by adopting a Grabbs criterion;
step SA 1134: fitting the ellipse by adopting a least square method again;
step SA1135, judging whether a noise point is contained; if the noise point is included, the process goes back to step SA1133, and if the noise point is not present, the marker is located by the center of the ellipse.
Although the set marker is in a circular ring shape, the surface of a human body is three-dimensional and cannot be completely horizontal, so that the shot marker is closer to an elliptical ring, and an ellipse is adopted for the marker in the inventionAnd (6) fitting. The principle of the standard least squares ellipse fitting algorithm is as follows: the general equation of the ellipse is shown in equation (1). And (3) taking n points to be fitted in the image, wherein the coordinate of the ith point to be fitted is Pi (xi, yi), (i is 0,1,2, …, n), and the least square fitting result is the ellipse when the sum of squares of distances from all the points to be fitted to the ellipse is minimum, namely the ellipse when the formula (2) takes the minimum value. From the extreme value theory, when equation (3) is satisfied, equation (2) takes the minimum value. The linear equation system obtained by solving the equation (3) can obtain the parameters A, B, C, D, E and F of the general equation fitting the ellipse. The center coordinate (x) of the ellipse can be obtained from equation (4) from the parameters of the general equation of the ellipsecenter,ycenter)。
Ax2+Bxy+Cy2+Dx+Ey+F＝0 (1)
Figure BDA0003329685820000091
Figure BDA0003329685820000092
Figure BDA0003329685820000093
Preferably, the accuracy and the real-time performance of the positioning of the marker by the least squares ellipse fitting algorithm are improved. The fitting of the marker and the acquisition of the central position of the marker for positioning comprise:
extracting points on the outer contour of the marker;
fitting an ellipse by adopting a least square method;
calculating the distances from all fitting points to the center of the fitting ellipse;
eliminating noise points with abnormal distances by adopting a Grabbs criterion;
fitting the ellipse by adopting a least square method again, and judging whether the noise points exist or not; if the noise points are contained, jumping back to the mode of eliminating the noise points with abnormal distances by adopting the Grabbs rule, and if the noise points are not contained, positioning the marker by using the center of the ellipse.
After contour screening, most of noise in the image is removed, but sometimes a few extracted outer contour points of the mark are not on the outer contour of the mark, and the noise points cause that an ellipse fitted by a traditional least square ellipse fitting algorithm has larger deviation with a real ellipse, so that the ellipse needs to be fitted again after the noise points are removed. Specifically, the median of the x-axis coordinate and the y-axis coordinate of all points to be fitted is calculated, and the coordinate is taken as a reference point. Calculating to obtain an algebraic distance di (i is 0,1,2 …, n) between each point to be fitted and the reference point, regarding the group of data as a sample point set, removing gross error points in the sample according to the Grabbs criterion and a confidence probability of 90%, re-fitting the ellipse by using the residual sample points and checking whether the gross error points exist, removing the gross error points until no gross error points exist, finally fitting the residual points, and using the result for positioning the mark.
Preferably, since the patient has limited displacement under the fixation of the thermoplastic film and the markers are only present in a part of the image, in order to reduce unnecessary calculations, step SA1135 is followed by step SA 1136: and intercepting a rectangle which takes the center of the fitted ellipse as the center and the length and width as the preset multiple of the long axis and the short axis of the ellipse as a region of interest (ROI), wherein the region of interest represents that the subsequent image is only subjected to ellipse fitting in the region of interest.
And moreover, compared with the coordinate system established by the whole image, the coordinate value is obviously reduced, and the calculation speed of the ellipse fitting algorithm can be improved.
The invention further discloses a tumor target area displacement monitoring device in another embodiment, which comprises an image acquisition unit, a marker and an image processing unit. Illustratively, the image acquisition unit is used for acquiring images. For example, the image capturing unit is an industrial camera, as shown in fig. 4, and in operation, the industrial camera 1 is fixed above the treatment couch 6 with the support 5, perpendicular to the tumor-bearing part of the patient, the part is photographed, and then the image is transmitted to the image processing unit (not shown). The marker 2 is used for positioning the tumor position, is made of a reflective material, is used for fixing the body surface of a patient, and is opposite to the position of the tumor, so as to mark the target region of the tumor, and the mark 3 in the graph is a patient model. The image processing unit analyzes and processes the received image, and finally obtains the result of the displacement of the target area of the tumor, thereby providing reference opinions for the treatment of doctors. In particular, the image processing unit processes the image for performing the steps of any of the above-described method embodiments. Compared with the method that the displacement of the target area of the tumor is monitored in real time by adopting the metal marker through X-ray molding, the reflective marker adopted by the invention can not bring additional radiation and infection side effects to patients. Preferably, in order to facilitate the operation of the doctor, the device further comprises a display unit, wherein the display unit is connected with the image processing unit and displays the displacement of the tumor target area in an image.
Because the light reflected by the marker can reach the camera after being shielded by the thermoplastic film, most of the light is shielded by the thermoplastic film, so that the brightness of the marker is very dark and the color characteristic is not obvious in a captured image.
Further, in order to facilitate positioning of the marker, a microprism light-reflecting film 21 is attached to the surface of the marker. An annular light source 4 with a small divergence angle is mounted coaxially with the industrial camera, the annular light source 4 illuminating the marker perpendicularly. The microprism type reflecting film is a reflecting material prepared based on the refraction and total reflection principles of a cube corner pyramid prism. As can be seen from fig. 5a and 5b, after the small-angle light emitted from the periphery of the camera irradiates the microprism structure, most of the light reflects back to the camera, and compared with the general markers made of diffuse reflection materials, more light reflects to the camera, so that the brightness of the markers in the image is improved, and the extraction and positioning are easy.
Illustratively, in an embodiment of the present invention, the main parameters of the device-related device are as follows:
hardware devices and major parameters for the devices of Table 1
Figure BDA0003329685820000111
In another embodiment of the present invention, a computer-readable storage medium is further disclosed, wherein the medium stores a computer program, and the computer program is executed to perform the method for monitoring displacement of a target region of a tumor according to any one of the above embodiments.
In another embodiment of the present invention, a computer device is further disclosed, which includes a processor, a storage medium, and a computer program stored on the storage medium, wherein the processor reads and executes the computer program from the storage medium to perform the tumor target displacement monitoring method described in any of the above embodiments.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (10)

1. A method for monitoring displacement of a tumor target area is characterized in that,
the method comprises the following steps:
step S1: setting a treatment point on the thermoplastic film, wherein the treatment point is a position irradiated by radiotherapy rays; positioning a marker, wherein the position of the marker corresponds to the target region of the tumor;
step S2: and calculating the displacement value of the tumor target area according to the relative displacement of the marker and the treatment point.
2. The method of claim 1,
the step of locating the marker comprises:
SA101, extracting feature points on the physical feature markers;
and SA102, matching the characteristic points in the real-time image and the reference image by adopting a characteristic point matching algorithm, and calculating the displacement of the characteristic points to position the marker.
3. The method of claim 1,
the marker is a geometric marker;
the step of locating the marker comprises:
SA111, segmenting the marker and the background;
SA112, marking the marker outline by adopting a fitting algorithm;
and SA113, determining the geometric center position of the marker, and positioning the marker.
4. The method of claim 3,
wherein the color of the marker adopts one of three primary colors;
step SA111 specifically includes the following steps:
SA1111, splitting the collected color image into three gray level images of three channels of red, green and blue;
SA1112 subtracts the gray value of the pixel in the image corresponding to the color channel of the marker from the gray value of the pixel corresponding to the other two channels.
5. The method of claim 3,
the step SA112 specifically includes:
SA 1121: calculating the outline of the gray level image containing the marker by using a Canny algorithm;
SA 1122: eliminating the contours with the areas smaller than a set threshold value in the contours;
SA 1123: and solving convex hulls from all the contours of each marker, and calculating to obtain the outer contour of the marker.
6. The method of claim 3,
step SA113 specifically includes the following steps:
SA 1131: extracting points on the outer contour of the marker;
SA 1132: fitting an ellipse by adopting a least square method;
SA 1133: calculating the distances from all the fitting points to the center of the fitting ellipse, and eliminating noise points with abnormal distances by adopting a Grabbs criterion;
SA 1134: fitting the ellipse by adopting a least square method again;
SA 1135: judging whether a noise point is contained; if the noise point is included, the process goes back to step SA1133, and if the noise point is not present, the marker is located by the center of the ellipse.
7. The method of claim 6,
the method further comprises step SA 1136: and taking the center of the ellipse as a center, and taking a rectangular area with the length and the width being preset multiples of the elliptical axis as an interested area of the next frame image, wherein the interested area represents that the subsequent image is only subjected to ellipse fitting in the interested area.
8. Tumor target volume displacement monitoring device using the method of any one of claims 1-7,
the apparatus comprises:
an image acquisition unit for acquiring an image, wherein the image acquisition unit is coaxially mounted with a small divergence angle annular light source and handles with the marker setting;
the marker is used for positioning the tumor position, wherein a microprism reflective membrane is attached to the surface of the marker;
and the image processing unit is used for processing and calculating the image to obtain the displacement information of the target area of the tumor.
9. A computer-readable storage medium, on which a computer program is stored, the computer program being operative to perform the method for monitoring displacement of a tumor target according to any one of claims 1 to 7.
10. A computer device comprising a processor, a storage medium having a computer program stored thereon, the processor reading the computer program from the storage medium and executing the computer program to perform the method for tumor target displacement monitoring according to any one of claims 1 to 7.
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