阅读说明：本技术 X射线间隙透视中的k因子确定方法、装置和存储介质 (K factor determination method and device in X-ray interstitial fluoroscopy and storage medium ) 是由 费孝爱 杨友生 于 2019-10-24 设计创作，主要内容包括：本发明实施方式公开了一种X射线间隙透视中的K因子确定方法、装置和存储介质。方法包括：基于K因子的预设初始值执行X射线间隙透视,获取子图数目等于所述预设初始值的合成图；基于所述合成图的曝光剂量确定每张子图的真实曝光剂量；基于预设的目标曝光剂量和每张子图的真实曝光剂量,确定K因子的更新值。无需用户掌握专家经验知识,即可以确定K因子。本发明实施方式还可以提高图像质量。(The embodiment of the invention discloses a method and a device for determining a K factor in X-ray interstitial fluoroscopy and a storage medium. The method comprises the following steps: executing X-ray interval perspective based on a preset initial value of a K factor, and acquiring a composite graph with the number of sub-graphs equal to the preset initial value; determining a true exposure dose for each sub-image based on the exposure dose of the composite map; based on the preset target exposure dose and the true exposure dose for each sub-image, an updated value of the K-factor is determined. The K factor can be determined without requiring the user to have expert knowledge. The embodiment of the invention can also improve the image quality.)

1. A method (100) for K-factor determination in X-ray interstitial fluoroscopy, comprising:

performing X-ray interstitial fluoroscopy based on a preset initial value of the K factor, and acquiring a composite graph (101) with the number of sub-graphs equal to the preset initial value;

determining a true exposure dose for each sub-image based on the exposure dose of the composite map (102);

based on the preset target exposure dose and the true exposure dose for each sub-image, an updated value of the K-factor is determined (103).

2. The method (100) for determining the K-factor in X-ray interstitial fluoroscopy as claimed in claim 1, wherein the composite map (101) for acquiring the number of sub-maps equal to a preset initial value is: acquiring the composite image (201) using an image intensifier system;

the determining (102) a true exposure dose for each sub-image based on the exposure dose for the composite map comprises:

calculating a gray value of the composite map (202);

dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose for each sub-image (203);

the determining an updated value of the K-factor (103) based on the preset target exposure dose and the true exposure dose for each sub-map comprises:

the quotient of the target exposure dose divided by the true exposure dose for each sub-image is determined as an updated value of the K-factor (204).

3. The method (100) for determining the K-factor in X-ray interstitial fluoroscopy as claimed in claim 1, wherein the composite map (101) for acquiring the number of sub-maps equal to a preset initial value is: acquiring the composite map by using a flat panel detector (401);

the determining (102) a true exposure dose for each sub-image based on the exposure dose for the composite map comprises:

calculating a gray value of the composite map (402);

dividing the gray value by the quotient of the preset initial value to determine the real exposure dose of each sub-image (403);

the determining an updated value of the K-factor (103) based on the preset target exposure dose and the true exposure dose for each sub-map comprises:

determining a maximum allowed exposure dose for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy (404);

an updated value of the K-factor is determined based on the target exposure dose and the maximum allowed exposure dose for each sub-graph (405).

4. The method (100) for K-factor determination in X-ray interstitial fluoroscopy as claimed in claim 3, wherein said determining a maximum allowed exposure dose (404) for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy comprises:

taking the X-ray exposure parameters as retrieval items to query a relative exposure dose table so as to determine relative exposure doses corresponding to the X-ray exposure parameters;

and dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure dose to determine the maximum allowable exposure dose for each subgraph.

5. A K-factor determination apparatus (600) in X-ray interstitial fluoroscopy, comprising:

a composite map acquisition module (601) for performing an X-ray interstitial fluoroscopy based on a preset initial value of the K factor, acquiring a composite map with a number of subgraphs equal to the preset initial value;

a true exposure dose determination module (602) for determining a true exposure dose for each sub-image based on the exposure dose of the composite map;

a K factor determination module (603) for determining an updated value of the K factor based on a preset target exposure dose and the real exposure dose of each sub-image.

6. The device (600) for K-factor determination in X-ray interstitial fluoroscopy according to claim 5,

the composite image acquisition module (601) is used for acquiring the composite image by using an image intensifier system;

the real exposure dose determination module (602) is used for calculating the gray value of the composite map; dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose of each sub-image;

the K factor determination module (603) is configured to determine the updated value of the K factor as a quotient of the target exposure dose divided by the real exposure dose of each sub-graph.

7. The device (600) for K-factor determination in X-ray interstitial fluoroscopy according to claim 5,

the composite image acquisition module (601) is used for acquiring the composite image by using a flat panel detector;

the real exposure dose determination module (602) is used for calculating the gray value of the composite map; dividing the gray value by the quotient of the preset initial value to determine the true exposure dose of each sub-image;

the K factor determination module (603) is used for determining the maximum allowable exposure dose of each subgraph based on the real exposure dose of each subgraph and the X-ray exposure parameters adopted in the X-ray interval perspective; determining an updated value of the K-factor based on the target exposure dose and the maximum allowed exposure dose for each sub-graph.

8. The device (600) for K-factor determination in X-ray interstitial fluoroscopy according to claim 7,

the K factor determination module (603) is configured to query a relative exposure dose table using the X-ray exposure parameter as a search term to determine a relative exposure dose corresponding to the X-ray exposure parameter; and dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure dose to determine the maximum allowable exposure dose for each subgraph.

9. A K-factor determination apparatus (700) in X-ray interstitial fluoroscopy, comprising a processor (701) and a memory (702);

the memory (702) has stored therein an application executable by the processor (701) for causing the processor (701) to perform the steps of the method (100) for K-factor determination in X-ray interstitial fluoroscopy according to any of the claims 1 to 4.

10. A computer-readable storage medium, characterized in that computer-readable instructions are stored therein for performing the steps of the method (100) for K-factor determination in X-ray interstitial fluoroscopy as claimed in any one of the claims 1 to 4.

Technical Field

The invention relates to the technical field of X-ray imaging, in particular to a method and a device for determining a K factor in X-ray interstitial fluoroscopy and a storage medium.

Background

X-rays are magnetic radiation with wavelengths between those of ultraviolet and gamma rays. X-rays are transparent and have different penetration capabilities for substances of different densities. Medical applications typically use X-rays to project organs and bones of the human body to form medical images. X-ray imaging typically includes a fluoroscopy (fluorocopy) mode and a direct Digital Radiography (DR) mode.

Fluoroscopy procedures may involve high doses of radiation, and total exposure times may exceed an hour or more, depending on a number of factors including the type of examination, the patient's size, the equipment, the technique, etc. In order to reduce the total radiation dose, an interstitial perspective (English: Intermitent fluorocopy; German: Intermittiende Durchleuchung) mode has been introduced to limit the radiation dose as much as possible. For example, in U.S. patent application No. 61110463: single X-ray, Magnetic Resonance Imaging (MRI), intermittent fluoroscopy, ultrasound, or CAT scan images of the patient cochlea may be taken without the need to continuously generate X-rays and bring the patient to a high level throughout the procedure. Interstitial perspective is mainly applied to low frame rate modes (e.g., 0.5fps,1fps,2fps, etc.), and can significantly reduce radiation dose. Apart from the lower radiation dose, the interstitial fluoroscopy has at least the following advantages: (1) avoiding dynamic limitation of the image intensifier; (2) increasing the power limit of the tablet system.

In interstitial perspective, the K factor (K factor) is used to determine the number of subgraphs (sub-frames) in a composite map (frame). The K factor may control many parameters in the gap perspective. In the prior art, the K factor in the gap perspective needs to be set manually based on expert experience knowledge, and is usually kept constant in a specific application.

However, manually setting the K factor requires a user to have a lot of expert knowledge and is not user-friendly. In addition, the manually set K factor also makes it difficult to ensure image quality. Also, if the patient is changed, the K-factor, which remains unchanged, will not be suitable for a new patient.

Disclosure of Invention

The embodiment of the invention provides a method and a device for determining a K factor in X-ray interstitial fluoroscopy and a storage medium.

A method of K-factor determination in X-ray interstitial fluoroscopy, comprising:

executing X-ray interval perspective based on a preset initial value of a K factor, and acquiring a composite graph with the number of sub-graphs equal to the preset initial value;

determining a true exposure dose for each sub-image based on the exposure dose of the composite map;

based on the preset target exposure dose and the true exposure dose for each sub-image, an updated value of the K-factor is determined.

Therefore, the X-ray interval perspective is executed based on the preset initial value, the K factor is updated based on the target exposure dose and the real exposure dose of each sub-image, the K factor does not need to be set by a user based on expert experience knowledge of the user, and the setting difficulty of the user is reduced. In addition, the updated value of the K factor can ensure that the exposure dose meets the target, and the image quality is improved. Also, even if the patient is changed, the K-factor can be updated based on the embodiment of the present invention.

In one embodiment, the composite graph with the number of acquired subgraphs equal to the preset initial value is: acquiring the composite image by using an image intensifier system;

the determining the true exposure dose for each sub-image based on the exposure dose for the composite image comprises:

calculating the gray value of the composite image;

dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose of each sub-image;

the determining an updated value of the K factor based on the preset target exposure dose and the real exposure dose of each sub-graph comprises:

and determining the quotient of the target exposure dose divided by the real exposure dose of each subgraph as the updated value of the K factor.

Therefore, the embodiment of the invention realizes the automatic setting of the K factor when the image intensifier system images, and can improve the imaging quality of the image intensifier system.

In one embodiment, the composite graph with the number of acquired subgraphs equal to the preset initial value is: acquiring the synthetic image by using a flat panel detector;

the determining the true exposure dose for each sub-image based on the exposure dose for the composite image comprises:

calculating the gray value of the composite image;

dividing the gray value by the quotient of the preset initial value to determine the true exposure dose of each sub-image;

the determining an updated value of the K factor based on the preset target exposure dose and the real exposure dose of each sub-graph comprises:

determining a maximum allowable exposure dose for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy;

determining an updated value of the K-factor based on the target exposure dose and the maximum allowed exposure dose for each sub-graph.

Therefore, the method and the device realize automatic setting of the K factor during imaging of the flat panel detector, and can improve the imaging quality of the image flat panel detector. Moreover, the updating value of the K factor determined based on the maximum allowable exposure dose of each sub-image can ensure that the K factor is not set too high, thereby avoiding more electronic noise and further ensuring the imaging quality.

In one embodiment, the determining the maximum allowable exposure dose for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy comprises:

taking the X-ray exposure parameters as retrieval items to query a relative exposure dose table so as to determine relative exposure doses corresponding to the X-ray exposure parameters;

and dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure dose to determine the maximum allowable exposure dose for each subgraph.

Therefore, the embodiment of the invention can quickly determine the maximum allowable exposure dose of each sub-image based on a table look-up mode, and improves the operation speed.

A K-factor determination apparatus in X-ray interstitial fluoroscopy, comprising:

the synthetic image acquisition module is used for executing X-ray interstitial perspective based on a preset initial value of the K factor and acquiring a synthetic image with the number of sub-images equal to the preset initial value;

a true exposure dose determination module for determining a true exposure dose for each sub-image based on the exposure dose of the composite map;

and the K factor determining module is used for determining an updated value of the K factor based on the preset target exposure dose and the real exposure dose of each subgraph.

Therefore, the X-ray interval perspective is executed based on the preset initial value, the K factor is updated based on the target exposure dose and the real exposure dose of each sub-image, the K factor does not need to be set by a user based on expert experience knowledge of the user, and the setting difficulty of the user is reduced. In addition, the updated value of the K factor can ensure that the exposure dose meets the target, and the image quality is improved. Also, even if the patient is changed, the K-factor can be updated based on the embodiment of the present invention.

In one embodiment, the composite image acquisition module is configured to acquire the composite image using an image intensifier system;

the real exposure dose determining module is used for calculating the gray value of the synthetic image; dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose of each sub-image;

and the K factor determining module is used for dividing the target exposure dose by the real exposure dose of each subgraph to determine the target exposure dose as an updated value of the K factor.

Therefore, the embodiment of the invention realizes the automatic setting of the K factor when the image intensifier system images, and can improve the imaging quality of the image intensifier system.

In one embodiment, the composite map acquisition module is configured to acquire the composite map using a flat panel detector;

the real exposure dose determining module is used for calculating the gray value of the synthetic image; dividing the gray value by the quotient of the preset initial value to determine the true exposure dose of each sub-image;

the K factor determination module is used for determining the maximum allowable exposure dose of each subgraph based on the real exposure dose of each subgraph and the X-ray exposure parameters adopted in the X-ray interval perspective; determining an updated value of the K-factor based on the target exposure dose and the maximum allowed exposure dose for each sub-graph.

Therefore, the method and the device realize automatic setting of the K factor during imaging of the flat panel detector, and can improve the imaging quality of the image flat panel detector. Moreover, the updating value of the K factor determined based on the maximum allowable exposure dose of each sub-image can ensure that the K factor is not set too high, thereby avoiding more electronic noise and further ensuring the imaging quality.

In one embodiment, the K-factor determining module is configured to query a relative exposure dose table using the X-ray exposure parameter as a search term to determine a relative exposure dose corresponding to the X-ray exposure parameter; and dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure dose to determine the maximum allowable exposure dose for each subgraph.

Therefore, the embodiment of the invention can quickly determine the maximum allowable exposure dose of each sub-image based on a table look-up mode, and improves the operation speed.

A K factor determination device in X-ray interstitial fluoroscopy comprises a processor and a memory;

the memory has stored therein an application program executable by the processor for causing the processor to perform the steps of the method for K-factor determination in X-ray interstitial fluoroscopy as defined in any one of the above.

Therefore, the embodiment of the invention also realizes a K factor determination device based on a processor and a memory architecture, and the processor can execute the steps of the K factor determination method in the X-ray interstitial fluoroscopy.

A computer readable storage medium having stored therein computer readable instructions for performing the steps of the method for K-factor determination in X-ray interstitial fluoroscopy as defined in any one of the preceding claims

Accordingly, embodiments of the present invention also realize a computer readable storage medium, wherein computer readable instructions stored in the computer readable storage medium can execute the steps of the method for determining K-factor in X-ray interstitial fluoroscopy as described in any one of the above.

Drawings

Fig. 1 is an exemplary flowchart of a K-factor determination method in X-ray interstitial fluoroscopy according to an embodiment of the present invention.

FIG. 2 is an exemplary flow chart of a method for K-factor determination in X-ray interstitial fluoroscopy when an image intensifier system is used to detect images.

FIG. 3 is a diagram illustrating a reduction in K-factor compared to a predetermined initial value according to an embodiment of the present invention.

FIG. 4 is an exemplary flow chart of a method for K-factor determination in X-ray interstitial fluoroscopy when detecting an image with a flat panel detector.

FIG. 5 is a diagram illustrating an increase in the K factor compared to a predetermined initial value according to an embodiment of the present invention.

Fig. 6 is a block diagram of a K-factor determination apparatus in an X-ray interstitial perspective according to an embodiment of the present invention.

Fig. 7 is a block diagram of a K-factor determination device in an X-ray interstitial perspective having a memory-processor architecture according to an embodiment of the present invention.

Wherein the reference numbers are as follows:

Detailed Description

In order to make the technical scheme and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

For simplicity and clarity of description, the invention will be described below by describing several representative embodiments. Numerous details of the embodiments are set forth to provide an understanding of the principles of the invention. It will be apparent, however, that the invention may be practiced without these specific details. Some embodiments are not described in detail, but rather are merely provided as frameworks, in order to avoid unnecessarily obscuring aspects of the invention. Hereinafter, "including" means "including but not limited to", "according to … …" means "at least according to … …, but not limited to … … only". In view of the language convention of chinese, the following description, when it does not specifically state the number of a component, means that the component may be one or more, or may be understood as at least one.

In prior art X-ray interstitial fluoroscopy, the K-factor for controlling the number of sub-graphs in the composite map needs to be set manually based on expert empirical knowledge and is usually kept constant.

The applicant found that: the manual setting of the K factor requires a user to have a large amount of expert experience knowledge, and is not user-friendly. In addition, the manually set K-factor makes it difficult to guarantee image quality. For example, if the K factor is set too high, more electronic noise may be caused, and the image quality may be reduced; if the K factor is set too low, the target exposure dose cannot be reached due to power limitation, and image quality cannot be guaranteed. In addition, even fortunately, the K-factor is set to be appropriate for this gap perspective, and if the patient is changed, the K-factor may not be appropriate for the next gap perspective for the new patient.

In the embodiment of the invention, an intelligent mode is introduced to automatically update the K factor, so that the proper K factor can be automatically determined, the requirement on expert experience knowledge is reduced, and the use by a user is facilitated. Moreover, the embodiment of the invention can also improve the image quality. In addition, according to the embodiment of the invention, even if the patient is replaced, the K factor can be flexibly adjusted.

Fig. 1 is an exemplary flowchart of a K-factor determination method in X-ray interstitial fluoroscopy according to an embodiment of the present invention.

As shown in fig. 1, the method 100 includes:

step 101: and performing X-ray interval perspective based on a preset initial value of the K factor, and acquiring a composite graph with the number of sub-graphs equal to the preset initial value.

Here, the X-ray interstitial fluoroscopy is performed based on an initial value of the K factor set in advance. In the X-ray interstitial fluoroscopy, exposure parameters such as a target exposure dose, a tube voltage, a tube current, and an exposure time are set. Exposure parameters such as tube voltage, tube current and exposure time are related to preset initial values, and the target exposure dose is determined by a user. After the X-ray interstitial fluoroscopy is executed, a composite map obtained by the X-ray interstitial fluoroscopy of this time can be acquired, and the composite map comprises subgraphs with preset initial values.

For example, if the preset initial value of the K factor is 10, a composite graph including 10 subgraphs may be obtained in step 101; if the preset initial value of the K factor is 8, a composite graph including 8 subgraphs can be obtained in step 101; if the preset initial value of the K factor is 15, a composite map comprising 15 subgraphs can be obtained in step 101.

Step 102: the true exposure dose for each sub-image is determined based on the exposure dose of the composite image.

Here, by calculating the gray-scale values of the composite map acquired in step 101, the exposure dose of the composite map can be determined. The exposure dose determined based on the gray-scale value is the true exposure dose. The true exposure dose will typically deviate from the target exposure dose. With the exposure dose determined based on the gray-scale values, the true exposure dose for each sub-image can be determined.

For example, assuming that the exposure dose of the composite map is M and the number of subgraphs is N, the real exposure dose of each subgraph is M/N.

Step 103: based on the preset target exposure dose and the true exposure dose for each sub-image, an updated value of the K-factor is determined.

The preset target exposure dose is the target exposure dose used in the X-ray interstitial fluoroscopy executed in step 101. Here, the result of dividing the preset target exposure dose by the real exposure dose of each sub-image acquired in step 102 is an updated value of the K factor. Then, with the updated value of the K factor, the subsequent X-ray interstitial fluoroscopy is performed again. For example, exposure parameters such as tube voltage, tube current, exposure time, etc. may be adjusted based on the updated value of the K factor.

Therefore, in the embodiment of the invention, the updated value of the K factor is determined based on the operation result of the target exposure dose and the real exposure dose of each sub-image, and the updated value of the K factor can be ensured to meet the target exposure dose, thereby improving the image quality. Moreover, the user does not need to manually set the K factor, and the user does not need to have a large amount of expert experience knowledge, so that the user can use the system conveniently. In addition, the K-factor can be updated based on embodiments of the present invention even if the patient is changed.

In the application of the process shown in fig. 1, the image device may be implemented as an image intensifier system.

Specifically, the image intensifier system includes an image intensifier, a camera, a monitor, and the like. The image formed by the X-ray penetrating through the irradiated object is projected to the image receiving end of the image intensifier, so that the receiving end of the image intensifier is excited to generate a weak visible light image. The light generated by the visible light image excites the photocathode to generate escaping electrons, and the escaping electrons are accelerated and focused to the image output end of the image intensifier under the action of a high-voltage electric field. Under the double action of electrons and accelerated convergence, the image output end screen of the image intensifier generates a visible light image with enough brightness. The image brightness generated by the fluorescent screen makes the electronic camera sensitive, thereby realizing the conversion of X-ray → visible light signal → electric signal. The electronic image converted to an optical signal can be processed by the camera and transmitted to a further location for viewing using a monitor, thereby keeping the operator away from the radiation.

In one embodiment, the step 101 of obtaining the composite graph with the number of subgraphs equal to the preset initial value includes: acquiring a composite image by using an image intensifier system; determining the true exposure dose for each sub-image based on the exposure dose for the composite image in step 102 comprises: calculating the gray value of the composite image; dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose of each sub-image; determining the updated value of the K factor based on the preset target exposure dose and the real exposure dose of each sub-graph in step 103 comprises: the quotient of the target exposure dose divided by the true exposure dose for each sub-image is determined as the updated value of the K-factor. The sensitivity of the image intensifier system is understood not to be the sensitivity of the image intensifier tube itself, but rather the sensitivity of the entire image intensifier system, i.e. the sum of the sensitivities of the image intensifier tube, the camera and the monitor.

In the application of the process shown in fig. 1, the imaging device may be implemented as a flat panel detector.

For example, the flat panel detector may be implemented as an amorphous selenium flat panel detector. The amorphous selenium flat panel detector may include a collector matrix, a selenium layer, a dielectric layer, a top electrode, and a protective layer. The collector matrix is composed of Thin Film Transistors (TFTs) arranged in an array element fashion. The amorphous selenium semiconductor material is formed into a thin film above the thin film transistor through vacuum evaporation, and the thin film is sensitive to X rays and has high image resolution capability. The top electrode is connected with a high-voltage power supply. When X-rays are incident, the X-rays can only vertically reach the amorphous selenium along the direction of the electric field due to the electric field formed on the surface of the amorphous selenium by the high-voltage power supply. The amorphous selenium converts X-ray into electric signal and stores it in the storage capacitor, the pulse control gate circuit makes the thin film transistor conduct, the electric charge stored in the storage capacitor is sent to the charge amplifier to output, the photoelectric signal conversion is completed, and then the conversion is carried out by the digital converter to form the X-ray image in digital format.

As another example, the flat panel detector may be implemented as an amorphous silicon flat panel detector. The amorphous silicon flat detector is an indirect digital X-ray imaging, and has a basic structure that the surface is provided with a layer of scintillator material (cesium iodide or sulfur oxide), the next layer is a photodiode circuit with amorphous silicon as the material, and the lowest layer is a charge reading circuit. The X-ray attenuated after penetrating through an object to be detected is converted into visible light by a scintillator on the surface of the detector, the visible light is converted into an electric signal by an amorphous silicon photodiode array under the scintillator, stored charges are formed on the capacitance of each photodiode, the stored charge amount of each pixel is in direct proportion to the intensity of the incident X-ray, the stored charges of each pixel are scanned and read under the action of a charge reading circuit, and the X-ray image in a digital format is formed after the stored charges are converted by a digital converter.

In one embodiment, the step 101 of obtaining the composite graph with the number of subgraphs equal to the preset initial value includes: acquiring a composite image by using a flat panel detector; determining the true exposure dose for each sub-image based on the exposure dose for the composite image in step 102 comprises: calculating the gray value of the composite image; dividing the gray value by the quotient of the preset initial value of the K factor to determine the true exposure dose of each sub-image; determining the updated value of the K factor based on the preset target exposure dose and the real exposure dose of each sub-graph in step 103 comprises: determining a maximum allowable exposure dose for each sub-image based on the real exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interval fluoroscopy in step 101; based on the target exposure dose and the maximum allowed exposure dose for each sub-map, an updated value of the K-factor is determined.

Preferably, determining the maximum allowable exposure dose for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy in step 101 comprises: taking the X-ray exposure parameters as retrieval items to query a relative exposure dose table so as to determine relative exposure doses corresponding to the X-ray exposure parameters; the maximum allowable exposure dose for each sub-map is determined by dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure doses.

The X-ray imaging system may be preconfigured with a relative exposure dose table. The relative exposure dose table stores the corresponding relationship between the X-ray exposure parameters and the relative exposure dose, so that the corresponding relative exposure dose can be obtained by looking up the table when the X-ray exposure parameters are set. The X-ray exposure parameters may include one or more items such as tube voltage, tube current, and exposure time, among others. In the relative exposure dose table, a maximum relative exposure dose corresponding to the maximum value of the X-ray exposure parameter is stored.

A specific example of determining the maximum allowable exposure dose for each sub-map based on a relative exposure dose table is described below.

Example (1): assuming that a preset initial value of the K factor is 10; the exposure dose for the composite map is 50 nanogold (nGy), and the true exposure dose for each subgraph is (50/10) ═ 5 nGy. In the X-ray interstitial fluoroscopy performed with the preset initial value of the K factor (i.e., 10), the exposure parameter is (exposure voltage: 50 kv; exposure current: 4.732 mA; exposure time: 7.1ms), and by referring to the relative exposure dose table, the relative exposure dose corresponding to the exposure parameter (exposure voltage: 50 kv; exposure current: 4.732 mA; exposure time: 7.1ms) can be retrieved to 125. Also, the maximum relative exposure dose in the relative exposure dose table (the maximum relative exposure dose is related to the maximum power of the X-ray imaging system) is 227. Thus, it can be calculated: the maximum allowable exposure dose per sub-graph was 5(nGy) × (227/125) ═ 9.08 (nGy).

An updated value of the K factor may then be determined based on the preset target exposure dose and the true exposure dose for each sub-image.

Example 1: assuming that the preset target exposure dose is 70nGy, then the new value of K is: (70/9.08), get the integer of 8. Example 2: assuming a preset target exposure dose of 110nGy, the new value of K is: 110/9.08, get 12 as a whole.

Then, a subsequent X-ray interstitial fluoroscopy is performed with the updated value of the K-factor.

Example (2): assuming that a preset initial value of the K factor is 6; the exposure dose of the resultant map is 60nGy, and the true exposure dose of each sub-map is (60/6) ═ 10 nGy. In the X-ray interstitial fluoroscopy performed with the preset initial value of the K factor (i.e., 6), the exposure parameter is (exposure voltage: 50 kv; exposure current: 3.981 mA; exposure time: 7.1ms), and by referring to the relative exposure dose table, the relative exposure dose corresponding to the exposure parameter (exposure voltage: 50 kv; exposure current: 3.981 mA; exposure time: 7.1ms) can be retrieved as 122. The maximum relative exposure dose in the relative exposure dose table is 227. Thus, the maximum allowable exposure dose for each sub-image can be calculated as: 10(nGy) × (227/122) ═ 18.6 (nGy).

An updated value of the K factor may then be determined based on the preset target exposure dose and the true exposure dose for each sub-image.

Example 1: assuming that the preset target exposure dose is 70nGy, then the new value of K is: (70/18.6), get the whole to 4. Example 2: assuming a preset target exposure dose of 140nGy, the new value of K is: 140/18.6, and 8 as a whole.

Then, a subsequent X-ray interstitial fluoroscopy is performed with the updated value of the K-factor.

While the above exemplary description describes exemplary examples of relative exposure dose schedules, target exposure doses, and exposure parameters, those skilled in the art will appreciate that this description is exemplary only and is not intended to limit the scope of embodiments of the present invention.

FIG. 2 is an exemplary flow chart of a method for K-factor determination in X-ray interstitial fluoroscopy when an image intensifier system is used to detect images.

As shown in fig. 2, the method includes:

step 201: x-ray interstitial fluoroscopy is performed based on a preset initial value of the K-factor, and a composite image is acquired using an image intensifier system.

Step 202: the gray values of the composite map are calculated.

Step 203: the gray value divided by the sensitivity of the image intensifier system is determined as the true exposure dose for each sub-image. Wherein the sensitivity of the image intensifier system is the sum of the sensitivities of the image intensifier tube, the camera and the monitor.

Step 204: the quotient of the target exposure dose divided by the true exposure dose for each sub-image is determined as the updated value of the K-factor.

Step 205: with the updated value of the K factor, the subsequent X-ray interstitial fluoroscopy is performed again.

Based on the flow chart shown in fig. 2, the updated value of the K factor may be lower than the preset initial value of the K factor or higher than the preset initial value of the K factor.

FIG. 3 is a diagram illustrating a reduction in K-factor compared to a predetermined initial value according to an embodiment of the present invention.

In fig. 3, the first composite image F1 is the composite image obtained by the image intensifier system when performing the X-ray interstitial fluoroscopy based on the preset initial value of the K factor (assumed to be 10) in step 201. As can be seen, composite graph F1 includes subgraph 301, subgraph 302, subgraph 303 … subgraph 310, which contains 10 subgraphs in total. Based on the procedure shown in fig. 2, the gray-scale value of the composite image F1 is calculated, and the gray-scale value is divided by the sensitivity of the image intensifier system to determine the true exposure dose for each sub-image. The target exposure dose is then divided by the true exposure dose for each sub-image to determine the updated value of the K factor. Assume that the updated value of the K factor is 6. Then, with the updated value of the K factor, the subsequent X-ray interstitial fluoroscopy is performed again.

In fig. 3, the second composite map F2 and the third composite map F3 are two consecutive composite maps acquired by the image intensifier system when performing X-ray interstitial fluoroscopy with the updated value of the K factor (changed to 6). As can be seen, composite graph F2 includes subgraph 311, subgraph 312, 312 … subgraph 316, which contains 6 subgraphs in total; composite graph F3 includes subgraph 317 and subgraph 318 … subgraph 322, which totally contains 6 subgraphs.

FIG. 4 is an exemplary flow chart of a method for K-factor determination in X-ray interstitial fluoroscopy when detecting an image with a flat panel detector.

As shown in fig. 4, the method includes:

step 401: and performing X-ray interstitial fluoroscopy based on a preset initial value of the K factor, and acquiring a composite image by using a flat panel detector.

Step 402: the gray values of the composite map are calculated.

Step 403: and dividing the gray value by the quotient of the preset initial value of the K factor to determine the true exposure dose of each sub-image.

Step 404: the maximum allowed exposure dose for each sub-image is determined based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy in step 401. Here, the method specifically includes: taking the X-ray exposure parameters as retrieval items to query a relative exposure dose table so as to determine relative exposure doses corresponding to the X-ray exposure parameters; the maximum allowable exposure dose for each sub-map is determined by dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure doses.

Step 405: based on the target exposure dose and the maximum allowed exposure dose for each sub-map, an updated value of the K-factor is determined.

Step 406: with the updated value of the K factor, the subsequent X-ray interstitial fluoroscopy is performed again.

Based on the flow chart shown in fig. 4, the updated value of the K factor may be lower than the preset initial value of the K factor or higher than the preset initial value of the K factor.

FIG. 5 is a diagram illustrating an increase in the K factor compared to a predetermined initial value according to an embodiment of the present invention.

In fig. 5, the first composite map F1 is a composite map obtained by the flat panel detector when performing X-ray interstitial fluoroscopy based on a preset initial value of the K factor (assumed to be 5) in step 401. As can be seen, composite graph F1 includes subgraph 501, subgraph 502, subgraph 503 … subgraph 505, which contains 5 subgraphs in total. Calculating the gray value of the composite image F1 based on the flow shown in FIG. 4, dividing the gray value by the quotient of the preset initial value of the K factor, and determining the true exposure dose of each sub-image; taking the X-ray exposure parameters as retrieval items to query a relative exposure dose table so as to determine relative exposure doses corresponding to the X-ray exposure parameters; dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure doses to determine the maximum allowable exposure dose of each subgraph; the target exposure dose is then divided by the maximum allowable exposure dose for each sub-image to determine an updated value for the K-factor. Assume that the updated value of the K factor is 6. Then, a subsequent X-ray interstitial fluoroscopy is performed with the updated value of the K-factor.

In fig. 5, the second composite map F2 and the third composite map F3 are two consecutive composite maps acquired by the flat panel detector when performing the X-ray interstitial fluoroscopy with the updated value of the K factor (changed to 6). As can be seen, composite graph F2 includes subgraph 506, subgraph 507 … subgraph 512, which contains 6 subgraphs in total; composite graph F3 includes subgraph 513, subgraph 514 … subgraph 518, which contains 6 subgraphs in total.

Based on the above description, the embodiment of the invention also provides a K factor determination device in the X-ray interstitial fluoroscopy.

Fig. 6 is a block diagram of a K-factor determination apparatus in an X-ray interstitial perspective according to an embodiment of the present invention.

As shown in fig. 6, the K-factor determination apparatus 600 in X-ray interstitial fluoroscopy includes:

a composite map obtaining module 601, configured to perform X-ray interstitial fluoroscopy based on a preset initial value of the K factor, and obtain a composite map with a number of subgraphs equal to the preset initial value;

a true exposure dose determination module 602 for determining a true exposure dose for each sub-image based on the exposure dose of the composite map;

a K factor determining module 603, configured to determine an updated value of the K factor based on the preset target exposure dose and the real exposure dose of each sub-graph.

In one embodiment, the composite image acquisition module 601 is configured to acquire a composite image using an image intensifier system; a true exposure dose determination module 602, configured to calculate a gray value of the composite map; dividing the gray value by the quotient of the sensitivity of the image intensifier system to determine the true exposure dose of each sub-image; a K factor determining module 603 for determining the quotient of the target exposure dose divided by the real exposure dose of each sub-image as the updated value of the K factor.

In one embodiment, the composite map acquisition module 601 is configured to acquire a composite map using a flat panel detector; a true exposure dose determination module 602, configured to calculate a gray value of the composite map; dividing the gray value by the quotient of the preset initial value of the K factor to determine the true exposure dose of each sub-image; a K-factor determining module 603 for determining a maximum allowable exposure dose for each sub-image based on the true exposure dose for each sub-image and the X-ray exposure parameters employed in the X-ray interstitial fluoroscopy; based on the target exposure dose and the maximum allowed exposure dose for each sub-map, an updated value of the K-factor is determined.

In one embodiment, the K-factor determining module 603 is configured to query a table of relative exposure doses with the X-ray exposure parameter as a search term to determine a relative exposure dose corresponding to the X-ray exposure parameter; the maximum allowable exposure dose for each sub-map is determined by dividing the maximum relative exposure dose in the relative exposure dose table by the quotient of the relative exposure doses.

Fig. 7 is a block diagram of a K-factor determination device in an X-ray interstitial perspective having a memory-processor architecture according to an embodiment of the present invention.

As shown in fig. 7, the K-factor determination apparatus 700 in X-ray interstitial fluoroscopy includes: a processor 701 and a memory 702; in which a memory 702 has stored therein an application executable by the processor 701 for causing the processor 701 to perform the steps of the K-factor determination method as described in any one of the above.

The memory 702 may be embodied as various storage media such as an Electrically Erasable Programmable Read Only Memory (EEPROM), a Flash memory (Flash memory), and a Programmable Read Only Memory (PROM). The processor 701 may be implemented to include one or more central processors or one or more field programmable gate arrays, wherein the field programmable gate arrays integrate one or more central processor cores. In particular, the central processor or central processor core may be implemented as a CPU or MCU.

It should be noted that not all steps and modules in the above flows and structures are necessary, and some steps or modules may be omitted according to actual needs. The execution order of the steps is not fixed and can be adjusted as required. The division of each module is only for convenience of describing adopted functional division, and in actual implementation, one module may be divided into multiple modules, and the functions of multiple modules may also be implemented by the same module, and these modules may be located in the same device or in different devices.

The hardware modules in the various embodiments may be implemented mechanically or electronically. For example, a hardware module may include a specially designed permanent circuit or logic device (e.g., a special purpose processor such as an FPGA or ASIC) for performing specific operations. A hardware module may also include programmable logic devices or circuits (e.g., including a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The implementation of the hardware module in a mechanical manner, or in a dedicated permanent circuit, or in a temporarily configured circuit (e.g., configured by software), may be determined based on cost and time considerations.

The present invention also provides a machine-readable storage medium storing instructions for causing a machine to perform a method as described herein. Specifically, a system or an apparatus equipped with a storage medium on which a software program code that realizes the functions of any of the embodiments described above is stored may be provided, and a computer (or a CPU or MPU) of the system or the apparatus is caused to read out and execute the program code stored in the storage medium. Further, part or all of the actual operations may be performed by an operating system or the like operating on the computer by instructions based on the program code. The functions of any of the above-described embodiments may also be implemented by writing the program code read out from the storage medium to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion unit connected to the computer, and then causing a CPU or the like mounted on the expansion board or the expansion unit to perform part or all of the actual operations based on the instructions of the program code.

Examples of the storage medium for supplying the program code include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROMs, CD-R, CD-RWs, DVD-ROMs, DVD-RAMs, DVD-RWs, DVD + RWs), magnetic tapes, nonvolatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer via a communications network.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.