Method, system and equipment for determining residence time of afterloading radioactive source in real time

Abstract

The invention discloses a real-time determination method, system and equipment for residence time of an afterloading radioactive source, and relates to the technical field of radioactive source detection, and the method comprises the steps: obtaining a radioactive source contour from a video image, screening a longest transverse line segment from the video image, and obtaining an end point coordinate of the longest transverse line segment; searching each scale point on the scale line from the end point coordinate along the direction perpendicular to the scale line by utilizing an iterative vertical line scale line method, selecting the scale point corresponding to the minimum distance from all the distances according to the distance between each scale point and the end point coordinate, and taking the scale point as a radioactive source coordinate; recording the radioactive source coordinate of each frame in the video image, eliminating and fusing the noise frame, obtaining the staying duration of the radioactive source in each radioactive source coordinate according to the video frame rate of the video image and the radioactive source coordinate of each frame, and filtering the preset short staying duration from all the staying durations. According to the invention, the residence position and time of the afterloading radioactive source can be accurately determined.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation source detection, and particularly relates to a method, a system and a device for real-time determination of the residence time of a radioactive source in a remote afterloader. Background Art

[0002] Brachytherapy is a form of radiotherapy. During operation, the radiation source is directly placed into the tissue to be treated or into the natural cavities of the human body, such as the nasopharynx, esophagus, cervix, etc. for irradiation. A remote afterloader is a common medical device used to implement brachytherapy.

[0003] During afterloading treatment, the dose is calculated from the residence points and times at different positions. Therefore, the time accuracy and position accuracy of the radiation source directly affect the residual tumor volume, the high-risk target volume HRCTV-D90%, and D2cm of the bladder, rectum, sigmoid colon, and small intestine 3Dose accuracy. According to experiments, in cervical cancer afterloading radiotherapy, when the position of the radiation source has a 1mm error, the residual tumor volume and the prescription dose envelope volume of the high-risk target area HRCTV decrease by an average of 0.8%; when there is a 2mm error, the average decrease is 1.9%; when there is a 3mm error, the average decrease is 3.1%. The above clinical research data show that the accuracy of the afterloading radiation source radiotherapy plan residence position and time is very important for the efficacy and safety of afterloading patients. Among the existing detection methods, the traditional method of detecting the source residence position accuracy usually uses the film method. It is necessary to design a plan with several fixed-interval residence points and a certain residence time. It is executed on a specific phantom with a film, expose the film, and the point with the largest grayscale on the film is the source residence position. Then, a ruler is used to measure the maximum deviation between each two residence points as the source residence position deviation. Some people also use a special source in-place accuracy detection ruler for detection, and use a camera to observe the position of the source in the ruler. The source residence time detection usually uses a stopwatch, and a camera is used to observe the residence time of the source. In terms of precision and accuracy, although the stopwatch method has high precision (0.01s), there is no hardware-controlled start-stop timing mechanism between the stopwatch and the afterloader, and manual readings will produce large errors during measurement. The film method usually relies on visual observation and judgment, resulting in low precision (1mm), but the source itself is 3.5mm long and the exposure size is large. It is also easy to introduce human factors to find the source center, resulting in large errors. The ruler method has an accuracy of 0.5mm, but the position of the source is observed by the naked eye through a camera, which has low accuracy, especially when detecting complex cumulative errors. It is difficult to accurately observe the cumulative errors of multiple points. At present, the well-type ionization chamber method with relatively high accuracy is used in China. Its mathematical calculation accuracy can reach 0.07mm, and the residence time detection can be accurate to 0.09s. However, this method can only measure the in-place accuracy of a certain point (1255mm). Further research is needed to detect the cumulative in-place accuracy of the source. The shielding requirements of the well-type ionization chamber are high, which has certain limitations and is complex to operate.

[0004] Therefore, how to accurately determine the residence position and time of the after-loaded radioactive source is an important issue that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present invention provide a method, system and device for real-time determination of the residence time of a post-loader radiation source, which can solve the problem of how to accurately determine the residence position and time of a post-loader radiation source in the prior art.

[0006] An embodiment of the present invention provides a method for real-time determination of the residence time of a post-loading radiation source, comprising the following steps:

[0007] The multi-channel quality control ruler is connected to the after-loading brachytherapy machine through the radiation source connecting tube, receives the radiation source transmitted from the after-loading brachytherapy machine, and obtains the real-time video image of the multi-channel quality control ruler;

[0008] Establish a coordinate system with the preset position on the multi-channel quality control ruler as the origin; use the Line Segment Detector (LSD) to obtain the position coordinates of all scale lines on the multi-channel quality control ruler from the real-time video image; obtain the radiation source contour from the real-time video image through an edge detection operator and the findContours function for detecting image contours, and filter out the longest horizontal line segment parallel to the multi-channel quality control ruler in the radiation source contour to obtain the end point coordinates of the longest horizontal line segment; search for each scale line on the multi-channel quality control ruler in the direction perpendicular to the scale line from the end point coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end point coordinates, and use the position coordinates of this scale line as the radiation source coordinates;

[0009] Record the radiation source coordinates of each frame in the real-time video image, and obtain the residence time of the radiation source at each radiation source coordinate according to the video frame rate of the real-time video image and the radiation source coordinates of each frame, and filter out the preset short residence time from all residence times to obtain the residence time of the afterloader radiation source at each radiation source coordinate in real time.

[0010] Further, in the process of obtaining the position coordinates of all scale lines on the multi-channel quality control ruler from the real-time video image, only the line segments with an included angle of 75 degrees to 105 degrees with the horizontal direction need to be detected.

[0011] Further, the specific steps of the distance between the position coordinates of each scale line and the end point coordinates include:

[0012] Set the end point coordinates as (x 2 , y 2 );

[0013] Use the iterative formula to obtain the radiation source coordinate distance, and the formula is:

[0014]

[0015] where line_x represents the abscissa value of the position coordinates of the scale line, and line_y represents the ordinate value of the position coordinates of the scale line.

[0016] Further, the specific steps of obtaining the residence time of the radiation source at each radiation source coordinate include:

[0017] When the current position of each radiation source coordinate changes, obtain the first frame of the radiation source at the current position as frame m, and the first frame when the radiation source leaves the current position as frame m + t;

[0018] The residence time T of the radiation source at each radiation source coordinate is T m+t -T m ;

[0019] Among them, T m+t represents the time at the (m + t)-th frame, and T m represents the time at the m-th frame.

[0020] Furthermore, establishing a coordinate system with a preset position on the multi-channel quality control ruler as the origin specifically includes: establishing a coordinate system with the position where the scale line with a scale of 60 cm on the 5-channel quality control ruler is located as the origin.

[0021] An embodiment of the present invention provides a real-time determination system for the residence duration of a radioactive source of a afterloader, including:

[0022] A 5-channel quality control ruler (8), a black and white industrial camera (4), a radioactive source coordinate acquisition module, and a duration acquisition module;

[0023] The 5-channel quality control ruler (8) is connected to the afterloading brachytherapy machine (1) through a radioactive source connecting pipe (2);

[0024] The black and white industrial camera (4) is used to acquire real-time video images including the radioactive source of the afterloading brachytherapy machine (1) and the 5-channel quality control ruler (8);

[0025] The radioactive source coordinate acquisition module is used to establish a coordinate system with a preset position on the 5-channel quality control ruler (8) as the origin; use the Line Segment Detector (LSD) method to obtain the position coordinates of all scale lines on the 5-channel quality control ruler (8) from the real-time video images; obtain the radioactive source contour from the real-time video images through an edge detection operator and the findContours function for detecting image contours, and screen the longest horizontal line segment parallel to the multi-channel quality control ruler in the radioactive source contour, and obtain the end point coordinates of the longest horizontal line segment; search each scale line on the 5-channel quality control ruler (8) in a direction perpendicular to the scale line from the end point coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end point coordinates, and use the position coordinates of this scale line as the radioactive source coordinates;

[0026] The duration acquisition module is used to record the radioactive source coordinates of each frame in the real-time video images, obtain the residence duration of the radioactive source at each radioactive source coordinate according to the video frame rate of the real-time video images and the radioactive source coordinates of each frame, and filter out the preset short residence durations from all residence durations, and obtain the residence duration of the radioactive source of the afterloading brachytherapy machine (1) at each radioactive source coordinate in real time.

[0027] An embodiment of the present invention provides a computer device, including: a memory and a processor; the memory stores a computer program, and when the processor executes the computer program, it implements the above-mentioned real-time determination method for the residence duration of a radioactive source of a afterloader.

[0028] The embodiments of the present invention provide a method, system and device for real-time determination of the residence time of a radioactive source in a afterloader. Compared with the prior art, the beneficial effects are as follows:

[0029] Search each scale line on the multi-channel quality control ruler in a direction perpendicular to the scale line from the end point coordinates. According to the distance between the position coordinates of each scale line and the end point coordinates, select the scale line corresponding to the minimum distance from all distances, and use the position coordinates of this scale line as the radioactive source coordinates to determine the position of the radioactive source; then, determine the residence time of the radioactive source at each radioactive source coordinate position through the frame rate of the real-time video image. Screening the preset short residence time can remove the possibility of the radioactive source being captured in the video when passing by, and finally accurately obtain the residence time of the radioactive source at each position. Description of the Drawings

[0030] Figure 1 It is a software technical route flowchart provided by the embodiments of the present invention;

[0031] Figure 2 It is a main program logic diagram provided by the embodiments of the present invention;

[0032] Figure 3 It is the scale line extracted by the LSD algorithm provided by the embodiments of the present invention;

[0033] Figure 4 It is a rectangular area intercepted diagram provided by the embodiments of the present invention;

[0034] Figure 5 It is a captured diagram of the radioactive source position coordinates after the dilation and erosion operations provided by the embodiments of the present invention;

[0035] Figure 6 It is a structural schematic diagram provided by the embodiments of the present invention;

[0036] Figure 7 It is a connection schematic diagram of the afterloading brachytherapy machine and the radioactive source connecting pipe provided by the embodiments of the present invention;

[0037] Figure 8 It is a top view structural schematic diagram of the 5-channel quality control ruler provided by the embodiments of the present invention;

[0038] Figure 9 It is a structural schematic diagram of the iridium-192 radioactive source provided by the embodiments of the present invention;

[0039] Figure 10 It is an experimental result diagram provided by the embodiments of the present invention, where (a) is a physical diagram and (b) is a channel detail diagram.

[0040] Reference Signs:

[0041] 1 - Afterloading brachytherapy device, 2 - Radioactive source connecting tube, 3 - Support rod, 4 - Black and white industrial camera, 5 - Bracket, 6 - Base, 7 - Fluorescent plate, 8 - 5 - channel quality control ruler, 9 - Driving wire, 10 - Welding point, 11 - Stainless steel housing, 12 - Iridium - 192 source. Specific embodiments

[0042] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0043] The embodiment of the present invention provides a method for real - time determination of the residence time of a radioactive source in a afterloading device, including the following steps:

[0044] Step 1: The 5 - channel quality control ruler (multi - channel quality control ruler) is connected to the afterloading brachytherapy device through a radioactive source connecting tube, receives the radioactive source transmitted from the afterloading brachytherapy device, and acquires the real - time video image of the 5 - channel quality control ruler.

[0045] Step 2: Establish a coordinate system with a preset position on the 5 - channel quality control ruler as the origin; use the Line Segment Detector (LSD) to obtain the position coordinates of all scale lines on the 5 - channel quality control ruler from the real - time video image; obtain the radioactive source contour from the real - time video image through an edge detection operator and the findContours function for detecting image contours, and screen the longest horizontal line segment parallel to the multi - channel quality control ruler in the radioactive source contour to obtain the end - point coordinates of the longest horizontal line segment; search each scale line on the 5 - channel quality control ruler in a direction perpendicular to the scale line from the end - point coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end - point coordinates, and use the position coordinates of this scale line as the radioactive source coordinates. Among them, a coordinate system is established with the position of the scale line with a scale of 60 cm on the 5 - channel quality control ruler as the origin.

[0046] Step 3: Record the radioactive source coordinates of each frame in the real - time video image, obtain the residence time of the radioactive source at each radioactive source coordinate according to the video frame rate of the real - time video image and the radioactive source coordinates of each frame, and filter out the preset short - term residence time from all residence times to obtain the residence time of the radioactive source of the afterloading device at each radioactive source coordinate in real time.

[0047] I. System overview.

[0048] 1. System functions.

[0049] 1.1 Device Connection and Initialization: After successfully connecting to the hardware device and powering it on, perform device debugging and software initialization.

[0050] 1.2 Radiation Source Detection: Automatically detect the position and residence time of the radiation source.

[0051] 1.3 Plan Information Detection: Execute single-channel and multi-channel management plans to ensure that the radiation source stays according to the predetermined trajectory and time.

[0052] 1.4 Data Export: Export the monitoring data to an EXCEL spreadsheet for comparison with the set information in the planning system.

[0053] 1.5 Real-time Monitoring and Feedback: Real-time display the residence trajectory and take pictures to retain information.

[0054] 2. System Composition.

[0055] 2.1 Hardware Devices: This system uses the following hardware devices:

[0056] A 24fps black-and-white industrial camera 4, equipped with an 8mm lens and a 20-meter cable, a large bracket 5 and a matching adapter ring, a 5-channel quality control ruler 8 and a fluorescent plate 7, a base 6, a radiation source connecting pipe 2, a support rod 3, there is a welding point 10 between the drive wire 9 and the stainless steel housing 11. Afterloading brachytherapy machine 1 and related information: A certain brand of afterloading machine, the source output distance is 850mm, the radiation source uses an iridium-192 source 12, source size: Physical size:

[0057] 1.1×6.5mm, active size: 0.7×3.5mm, half-life: 74 days, general source activity: 10Ci (370Bq). As Figures 6 to 9 shown.

[0058] The experimental result diagram is as shown in Figure 10 (a) and (b).

[0059] 2.2 Software Modules: Device Debugging and Initialization Module, Radiation Source Detection Module, Plan Information Detection Module, Data Export Module, Real-time Monitoring and Feedback Module.

[0060] 3. System Design. The design content includes: Device Connection and Initialization; Radiation Source Detection; Plan Information Detection; Data Export; Real-time Monitoring and Feedback.

[0061] 4. System Process.

[0062] The technical route flow chart shows a work process involving hardware device debugging, software initialization, and plan information detection, as shown in Figure 1 shown.

[0063] The process is divided into two main parts: A. Equipment debugging and software initialization; B. Plan information detection.

[0064] A. Equipment debugging and software initialization.

[0065] 4A.1 Connect to the hardware device and power on successfully: First, the system needs to be connected to the hardware device and ensure successful power-on.

[0066] 4A.2 Perform equipment initialization: Equipment initialization includes debugging the hardware device and calibrating the boundary detection scale line.

[0067] 4A.3 After initialization is completed, the system will display a message indicating that the initialization is complete.

[0068] 4A.4 Open the plan file: Open the corresponding plan file to prepare for subsequent operations.

[0069] B. Plan information detection.

[0070] 4B.1 Click Start to prepare for detection: Click the Start to prepare for detection button to start the automatic detection process.

[0071] 4B.2 Start automatically detecting the position and residence time of the radiation source: The system will automatically detect the position and residence time of the radiation source, and at the same time record information such as different channels, residence positions, residence times, and real-time photos.

[0072] 4B.3 The afterloader starts to execute the plan file: The afterloader starts to execute the plan file, and sequentially executes the first channel, the second channel, the Nth channel.

[0073] 4B.5 Plan types: Plan types include single-channel vaginal applicator patient plans, 2-3 channel cervical cancer patient plans, multi-channel interstitial implantation patient plans, and afterloader quality control.

[0074] 4B.6 Export the measurement information to EXCEL: Export the measurement information to an EXCEL spreadsheet for plan verification, radiation source quality control, and information archiving for future use.

[0075] The main program logic is as Figure 2 shown.

[0076] The specific implementation steps are as follows:

[0077] (1) Video image preprocessing: The VideoCapture function is called through the OpenCV library to capture the video, save it frame by frame, and then process the images frame by frame. The preprocessing mainly includes the correction of the video image angle. For the accuracy of the radioactive source position, the acquired images need to be angle-corrected in the experiment. The specific process is to obtain the length and width of the image, specify the image center as the rotation center, calculate the two-dimensional rotation matrix of the image using cv2.getRotationMatrix2D, and use the cv2.warpAffine affine transformation function to rotate the image.

[0078] Rotation matrix:

[0079] (2) Extract the scale lines based on the LSD algorithm and the Numpy database and store the position coordinates of the scale lines:

[0080] The LSD algorithm is a line detection algorithm. Compared with the traditional Hough transform line detection algorithm, it was proposed by Rafael Grompone et al. It can obtain detection results with sub-pixel accuracy in linear time, is applicable to any digital image, and does not require parameter debugging. Its transformation extraction speed is much faster than that of the Hough transform extraction speed and has strong robustness. The goal of the experiment is the scale lines, so limit conditions will be set during the line detection process. The angle of the detected lines is set between 75° and 105°. There are three lengths of scale lines, and the experiment chooses to store them in groups using Numpy. As Figure 3 shown are the scale lines extracted by the LSD algorithm.

[0081] (3) Analyze the movement position of the radioactive source: Use the grayscale function to convert the image into a 16-bit grayscale image, check the coordinate order, and intercept the rectangular area, as Figure 4 shown. Use dilation and erosion operations to fill the gaps and eliminate interference. Use the Canny edge detection operator and the findContours function to obtain a more complete contour, and then filter the horizontal lines, select the longest horizontal line segment, and the end coordinates (x 2 , y 2 ) are the end coordinates of the longest line segment. The iterative vertical line scale line method is used to find the radioactive source coordinates:

[0082] line_x = line[0][0].

[0083] line_y = line[0][1].

[0084] Calculate the distance, and the formula uses iterative formula one:

[0085]

[0086] If the distance is closer than the current nearest scale line, update the nearest scale line and the distance until the position of the nearest scale line is found, which is recognized as the position of the radiation source and recorded. The contour image of the radiation source position is shown in Figure 5 as follows:

[0087] (4) Analyze the residence time of the radiation source: If the position of the current radiation source has changed, calculate the residence time, update the m-th frame at the current position and the (m + t)-th frame when there was no radiation source at the beginning. Calculate the residence time at each position according to the video frame rate and the frame position coordinates, filter out too short residence times to eliminate and fuse "noisy" frames, and calculate the residence time at each position (T = T m+t - T m ).

[0088] Conclusion:

[0089] Through the collaborative work with devices such as cameras and quality control rulers, this system realizes the real-time monitoring of the movement trajectory of the radiation source of the afterloading brachytherapy machine. By controlling the residence time and position of the radiation source in different channels, the software can provide personalized irradiation ranges for patients to meet different treatment needs. The real-time monitoring and data export functions ensure that the radiation source stays strictly according to the predetermined trajectory and time set by the treatment planning system, providing a strong guarantee for the safety and treatment effect of patients.

[0090] After the implementation of the present invention, it will help improve the accuracy of the residence point position and timer of the afterloading machine, help ensure the dose accuracy of patients using the afterloading machine for the treatment of cervical cancer, vaginal cancer, etc., guarantee the treatment effect, reduce risks, and be beneficial to patients.

[0091] An embodiment of the present invention provides a real-time determination system for the residence time of a radioactive source in a afterloader, including: a 5-channel quality control ruler 8, a black and white industrial camera 4, a radioactive source coordinate acquisition module, and a residence time acquisition module; the 5-channel quality control ruler 8 is connected to the afterloader for brachytherapy 1 through a radioactive source connecting pipe 2; the black and white industrial camera 4 is used to acquire real-time video images including the radioactive source of the afterloader for brachytherapy 1 and the 5-channel quality control ruler 8; the radioactive source coordinate acquisition module is used to establish a coordinate system with a preset position on the 5-channel quality control ruler 8 as the origin; use the Line Segment Detector (LSD) method to obtain the position coordinates of all scale lines on the 5-channel quality control ruler 8 from the real-time video images; obtain the radioactive source contour from the real-time video images through an edge detection operator and the findContours function for detecting image contours, and screen the longest horizontal line segment parallel to the multi-channel quality control ruler in the radioactive source contour, and obtain the end coordinates of the longest horizontal line segment; search each scale line on the 5-channel quality control ruler 8 in a direction perpendicular to the scale line from the end coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end coordinates, and use the position coordinates of this scale line as the radioactive source coordinates; the residence time acquisition module is used to record the radioactive source coordinates of each frame in the real-time video images, obtain the residence time of the radioactive source at each radioactive source coordinate according to the video frame rate of the real-time video images and the radioactive source coordinates of each frame, and filter out the preset short residence times from all residence times, and obtain the residence time of the radioactive source of the afterloader for brachytherapy 1 at each radioactive source coordinate in real time.

[0092] An embodiment of the present invention provides a computer device, including: a memory and a processor; the memory stores a computer program, and when the processor executes the computer program, the steps of a real-time determination method for the residence time of a radioactive source in a afterloader are implemented.

[0093] A specific embodiment is as follows:

[0094] This embodiment discloses a real-time determination method for the residence time of a radioactive source in a afterloader, and the specific steps include:

[0095] S1. Video image preprocessing: Obtain video images of the radioactive source and scale lines of the afterloader, capture the video by calling the VideoCapture function through the OpenCV library, save it frame by frame, and then process the images frame by frame.

[0096] S2. Extract scale lines based on the Lsd algorithm and the Numpy database and store the position coordinates of the scale lines.

[0097] S3. Analyze the movement position of the radioactive source.

[0098] Use the grayscale function to convert the image into a 16-bit grayscale image, check the coordinate order, and intercept the rectangular area, see Figure 4。Use dilation and erosion operations to fill gaps and eliminate interference. Use the Canny edge detection operator and the findContours function to obtain a relatively complete contour, and then filter the horizontal lines and select the longest horizontal line segment. The end coordinates (x 2 , y 2 ) are the end coordinates of the longest line segment. The iterative vertical scale line method is used to find the radioactive source coordinates:

[0099] line_x = line[0][0].

[0100] line_y = line[0][1].

[0101] Calculate the distance. The formula uses iterative formula one:

[0102]

[0103] S4. Analyze the residence time of the radioactive source. If the position of the current radioactive source changes, calculate the residence time, update the m-th frame of the current position and the (m + t)-th frame when there was no radioactive source at the beginning. Calculate the residence time at each position according to the video frame rate and the frame position coordinates, filter out too short residence times, eliminate and fuse "noisy" frames, and calculate the residence time at each position (T = T m+t -T m ).

[0104] The automatic detection system for the position accuracy of the radioactive source of the afterloading brachytherapy machine realizes the efficient monitoring of the movement trajectory of the radioactive source through the close cooperation of software and hardware devices. Its operation process is simple and clear, and its functions are comprehensive and practical, providing strong technical support for radiotherapy work and effectively ensuring the treatment safety and effect of patients.

[0105] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A real-time determination method for the dwell time of a radioactive source in a remote afterloader, characterized in that, Including the following steps: The multi-channel quality control ruler is connected to the afterloader brachytherapy machine through a radiation source connecting pipe, receives the radiation source transmitted from the afterloader brachytherapy machine, and obtains the real-time video image of the multi-channel quality control ruler; Establish a coordinate system with a preset position on the multi-channel quality control ruler as the origin; use the Line Segment Detector (LSD) to obtain the position coordinates of all scale lines on the multi-channel quality control ruler from the real-time video image; Obtain the radiation source contour from the real-time video image through an edge detection operator and the findContours function for detecting image contours, and filter out the longest horizontal line segment parallel to the multi-channel quality control ruler in the radiation source contour to obtain the end coordinates of the longest horizontal line segment; Search for each scale line on the multi-channel quality control ruler in a direction perpendicular to the scale line from the end coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end coordinates, and use the position coordinates of this scale line as the radiation source coordinates; Record the radiation source coordinates of each frame in the real-time video image, obtain the residence time of the radiation source at each radiation source coordinate according to the video frame rate of the real-time video image and the radiation source coordinates of each frame, and filter out the preset short residence time from all residence times to obtain the residence time of the afterloader radiation source at each radiation source coordinate in real time.

2. The real-time determination method for the dwell time of a radioactive source in a remote afterloader according to claim 1, wherein, During the process of obtaining the position coordinates of all scale lines on the multi-channel quality control ruler from the real-time video image, only the line segments with an included angle of 75 degrees to 105 degrees with the horizontal direction need to be detected.

3. The real-time determination method of the dwell time of the radiation source of the afterloader according to claim 1, wherein The specific steps of selecting the scale line corresponding to the minimum distance according to the distance between the position coordinates of each scale line and the end coordinates include: Set the end coordinates to (x 2 , y 2 ); Use the iterative formula to obtain the radiation source coordinate distance, and the formula is: where line_x represents the abscissa value of the position coordinates of the scale line, and line_y represents the ordinate value of the position coordinates of the scale line.

4. The real-time determination method of the dwell time of the radiation source of the afterloader according to claim 1, characterized in that, The specific steps of obtaining the residence time of the afterloader radiation source at each radiation source coordinate in real time include: When the position of each radiation source coordinate changes from the current position, obtain the first frame of the radiation source at the current position, denoted as the m-th frame, and the first frame when the radiation source leaves the current position, denoted as the (m + t)-th frame; The residence time T of the radiation source at each radiation source coordinate is T = T m+t - T m ; Among them, T m+t represents the time at the (m + t)-th frame, and T m represents the time at the m-th frame.

5. The real-time determination method of the dwell time of the radioactive source of the afterloader according to claim 1, wherein The establishment of the coordinate system with a preset position on the multi-channel quality control ruler as the origin specifically includes: establishing a coordinate system with the position of the scale line with a scale of 60 cm on the 5-channel quality control ruler as the origin.

6. A real-time determination system for the dwell time of a radioactive source in a remote afterloading unit, characterized in that, Including: A 5-channel quality control ruler (8), a black and white industrial camera (4), a radiation source coordinate acquisition module, and a duration acquisition module; The 5-channel quality control ruler (8) is connected to the afterloader brachytherapy machine (1) through a radiation source connecting pipe (2); The black and white industrial camera (4) is used to obtain the real-time video image including the radiation source of the afterloader brachytherapy machine (1) and the 5-channel quality control ruler (8); The radiation source coordinate acquisition module is used to establish a coordinate system with a preset position on the 5-channel quality control ruler (8) as the origin; use the Line Segment Detector (LSD) to obtain the position coordinates of all scale lines on the 5-channel quality control ruler (8) from the real-time video image; obtain the radiation source contour from the real-time video image through an edge detection operator and the findContours function for detecting image contours, and screen the longest horizontal line segment parallel to the multi-channel quality control ruler in the radiation source contour, and obtain the end coordinates of the longest horizontal line segment; search each scale line on the 5-channel quality control ruler (8) in a direction perpendicular to the scale line from the end coordinates, and select the scale line corresponding to the minimum distance from all distances according to the distance between the position coordinates of each scale line and the end coordinates, and use the position coordinates of this scale line as the radiation source coordinates; The duration acquisition module is used to record the radiation source coordinates of each frame in the real-time video image, obtain the duration of the radiation source staying at each radiation source coordinate according to the video frame rate of the real-time video image and the radiation source coordinates of each frame, filter out the preset short stay durations from all stay durations, and obtain the residence duration of the radiation source of the afterloading brachytherapy machine (1) at each radiation source coordinate in real time.

7. A computer device, comprising: A memory and a processor; The memory stores a computer program, wherein the processor, when executing the computer program, implements the method for real-time determination of the residence duration of the radiation source of an afterloading machine according to any one of claims 1 to 5.

Images