CN210603233U - X-ray focus measuring device - Google Patents

Abstract

The utility model is suitable for an X ray focus measures technical field, provides an X ray focus measuring device, including measuring platform and slit, the measuring platform top is provided with the guide pillar that the upper and lower direction extends, is equipped with the slit mounting bracket on the guide pillar, and the slit mounting bracket is along upper and lower direction and guide pillar direction movable assembly, and the slit is fixed on the slit mounting bracket, and measuring platform includes detector array and data acquisition module. The X-ray focus measuring device measures by using the principle of a slit imaging method, X-rays pass through a slit to form an image of a focus on a detector array, an imaging signal is obtained by detecting the image by the detector array, and then data are processed, so that the measuring precision is high, and the error is small. Further, the slit can be moved in the vertical direction, a plurality of focal data can be calculated, and the plurality of obtained focal data can be processed, thereby further improving the measurement accuracy.

Description

X-ray focus measuring device

Technical Field

The utility model belongs to the technical field of X ray focus measures, especially, relate to an X ray focus measuring device.

Background

The medical irradiation of X-ray diagnosis is the biggest source of artificial ionizing radiation to all human beings, and the X-ray machine as the main instrument of X-ray diagnosis is naturally concerned by all people, including how much the quality and performance of the X-ray machine, the radiation dose and the like. The quality and performance of the X-ray machine are detected by the detection rule mainly according to the technical indexes of the air kerma rate of rays, the radiation quality of radiation output, repeatability, linearity, resolution, the consistency of a radiation field and a light field, the focus of an X-ray tube and the like. The X-ray tube focus size is an important basic data when determining radiographic technical parameters. The significance of detecting the focus of the medical X-ray machine is as follows: (1) the X-ray machine has the advantages that the imaging quality is guaranteed, the definition is a key parameter of the imaging quality of the X-ray machine, if the definition is extremely poor, the diagnosis effect cannot be achieved, the factors influencing the definition in the X-ray machine are many, and the size of an equivalent focus is an important parameter influencing the definition. Since the focus of the medical X-ray machine affects the imaging performance, i.e. the sharpness, the focus of the bulb tube is smaller and better from the viewpoint of diagnostic effect alone, because the larger the focus is, the larger the penumbra generated during projection is, and the blurred edge of the image is, which is extremely disadvantageous to the diagnosis of diseases; (2) the function of the components in the high-voltage circuit, especially the reduction of the vacuum degree of the X-ray tube, can be checked by accurately measuring the change of the focus size and matching with the measurement of other quantities. In view of the power of the X-ray tube, the larger the focus, the better the heat dissipation performance, and the larger the power, the wider the application of the X-ray machine, so the smaller the focus of the tube should be under a certain power, the better.

The simplest way to generate X-rays is to hit a metal target with accelerated electrons. During the impact process, the electrons are suddenly decelerated and their lost kinetic energy is released in the form of photons, forming a continuum of the X-ray spectrum, known as bremsstrahlung. By increasing the accelerating voltage, the energy carried by the electrons is increased, and the inner layer electrons of the metal atoms are likely to be knocked out, so that the inner layer forms holes, the outer layer electrons jump back to the inner layer to fill the holes, and photons with the wavelength of about 0.1 nanometer are emitted. Since the energy released by the outer electron transition is quantized, the wavelength of the released photon is also concentrated in certain parts, forming characteristic lines in the X-spectrum, which is called characteristic radiation. The X-ray machine mainly utilizes the principle to generate X-rays for medical diagnosis.

The directionality of the X-ray is affected by the size, shape, direction of electron movement, etc. of the target, which will directly affect the sharpness of the image. The emission area of the X-rays is now defined: focal spot: the area where the electrons strike the target producing X-rays; actual focal spot: generating a real area region for radiography; effective focal spot: projection of the focal spot onto a reference plane. The size of the focus is determined by the width of the focus in the determined direction, specifying: the length of the focus is the direction of the collimator, and the width is the direction perpendicular to the collimator.

At present, methods for focus measurement of X-rays include a pinhole photography method and a star card measurement method.

(1) The method for measuring the satellite-card error is the simplest method for measuring the satellite-card error, but has a large measurement error, namely the method error, and the main factors influencing the method error are as follows: 1. uncertainty caused by the angle of the star card central axis deviating from the X-ray beam axis, 2, the angle of the star card central axis deviating from the X-ray beam axis and the consistency of the light field and the radiation field have larger influence. And the shooting is needed, and the process is complicated.

(2) The pinhole photography method adopts a pinhole plate and utilizes the pinhole imaging principle to obtain a focal radiographic image. The pinhole plate is made of high-ray absorption material, and is placed between focal point and film, and the distance between the pinhole plate and film is controlled, and the transillumination is completed according to the defined transillumination voltage and tube current so as to obtain focal image with defined blackness, and the image is directly measured to give out the size of focal point. The pinhole photography method also has larger measurement error, needs photography and has complicated process.

SUMMERY OF THE UTILITY MODEL

The utility model provides an X ray focus measuring device for solve current X ray focus measuring method and have great measuring error's problem.

The utility model provides an X-ray focus measuring device, which comprises a measuring platform and a slit, wherein a guide pillar extending in the up-down direction is arranged above the measuring platform, a slit mounting rack is arranged on the guide pillar, the slit mounting rack is movably assembled with the guide post along the up-down direction, the slit is fixed on the slit mounting rack, the measuring platform comprises a detector array and a data acquisition module, the detector array is used for detecting an image formed by the X-ray to be measured passing through the slit, the signal output end of the detector array is connected with the signal input end of the data acquisition module, the data acquisition module is used for acquiring data detected by the detector array, the signal output end of the data acquisition module is used for connecting the data processing module, and processing the data acquired by the data acquisition module to realize the measurement of the focus of the X-ray to be measured.

Optionally, the slit is a tungsten alloy slit.

Optionally, a driving module for driving the slit mounting frame to move up and down along the guide pillar is arranged on the slit mounting frame, the driving module includes a driving motor, a controller and an operation key unit, the operation key unit includes a start key, a shutdown key, a downward movement key and an upward movement key, a signal output end of the operation key unit is connected to a signal input end of the controller, a signal output end of the controller is connected to the driving motor, and the driving motor is used for driving the slit mounting frame to move up and down along the guide pillar.

Optionally, a scale is provided along the guide post.

Optionally, a fixing mechanism for fixing the slit mounting bracket at a certain position on the guide post is disposed on the slit mounting bracket.

Optionally, the measurement platform further includes a housing, the detector array is horizontally disposed on an upper end surface of the housing, and the data acquisition module is disposed inside the housing.

Optionally, a rotating mechanism for driving the housing to rotate in the horizontal direction is disposed below the housing.

Optionally, the rotating mechanism is provided with a positioning mechanism at intervals of 90 degrees in the circumferential direction.

Optionally, the measurement platform further comprises the data processing module.

Optionally, a horizontal adjusting mechanism is arranged between the housing and the rotating mechanism.

The utility model has the advantages that: the utility model provides an X ray focus measuring device utilizes the principle of slit imaging method to measure, and X ray forms the image of focus on the detector array after the slit, surveys the imaging signal who obtains the focus through the detector array, and the imaging signal that the detector array detected is gathered to the data acquisition module, handles through the data that gather the data acquisition module to the measurement obtains focus data, and this kind of measurement mode's measurement accuracy is higher, and the error is less. Moreover, the slit can move along the up-down direction, when the slit is at different heights, a plurality of groups of focus data can be obtained through calculation according to the geometrical mathematical relationship of slit imaging, the obtained plurality of focus data are processed, for example, the average value is obtained, and more accurate focus data can be finally obtained, so that the X-ray focus measuring device is high in measurement precision and small in measurement error.

Drawings

FIG. 1 is a schematic diagram of the components of an X-ray focus measuring apparatus;

FIG. 2 is a schematic view of a specific structure of a slit;

FIG. 3 is a mechanical schematic diagram of an X-ray focus measuring device;

FIG. 4 is a schematic structural diagram of a drive module;

fig. 5 is a schematic view of the measurement principle of the X-ray focus measuring apparatus.

Detailed Description

The present embodiment provides an X-ray focus measuring apparatus, as shown in fig. 1, including a measuring platform and a slit 1, where the measuring platform includes a detector array 2, a data acquisition module 3, and a data processing module 4. The detector array 2 is used for detecting an image formed by the X-ray 5 to be detected passing through the slit 1, the signal output end of the detector array 2 is connected with the signal input end of the data acquisition module 3, and the signal output end of the data acquisition module 3 is connected with the signal input end of the data processing module 4.

In this embodiment, the slit 1 is specifically a tungsten alloy slit, that is, the material of the slit 1 is tungsten. Forming a diaphragm to image the X-ray. The size of the slit 1 is designed according to IEC60336 standard, the error is enlarged to +/-0.005 mm on the width of the slit 1, the width is consistent with domestic diagnosis regulations, and the minimum focus of measurement is 0.1mm according to the design size of the slit 1. Fig. 2 shows a schematic diagram of a specific structure of the slit 1. Since the structure of the slit 1 belongs to the prior art, the present embodiment will not be described in detail. In another embodiment, the slit 1 may be made of a gold-platinum alloy containing 10% platinum.

In this embodiment, the detector array 2 is formed by arranging a plurality of semiconductor sensors, and the unit area of the semiconductor sensors is 14 μm × 14 μm. The semiconductor resolution is improved to 7 mu m by adopting linear arrays which are distributed in a stepped way and have the total length of 30mm, and one linear array is 2160 units. The detector array 2 collects imaging signals of the X-rays passing through the slit 1, and converts the X-rays 5 into electrical signals.

The data acquisition module 3 dynamically acquires the electrical signals of the detector array 2 and transmits the electrical signals to the data processing module 4. In this embodiment, the data acquisition module 3 acquires the induced charge, converts the charge signal into a voltage signal, converts the voltage signal into a digital signal through the high-speed AD in the data acquisition module 3, acquires data through the FPGA in the data acquisition module 3, and outputs the data to the data processing module 4 through the FPGA. The parameters of high-speed AD are as follows: single chip 12 bit analog to digital converter product series; flexible sampling rate: 1.5, 3.0 and 10 MSPS; low power consumption: 59mW, 100mW and 250 mW; +5V single power supply; integral non-linear error: 0.5 LSB; differential non-linearity error: 0.3 LSB; signal-to-noise ratio (SNR): 70 dB; spurious Free Dynamic Range (SFDR): 86 dB; over-range indication; a 28 pin SOIC and a 28 pin SSOP package. In addition, the data acquisition module 3 may further be provided with a cache chip, the model IS ISSI IS61C6416AL, and the specific parameters are as follows: high-speed access time: 12ns, 15 ns; low active power: 175mW (typical); low standby power consumption: 1mW (typical); a TTL compatible interface level; single 5V +/-10% power supply; all-static operation: no clock or refresh requirements; available and 44-pin TSOP (type II) is packaged at 44-pin SOJ; commercial, industrial and automotive temperature ranges. The data acquisition module 3 is then essentially a data conversion module that converts the imaging data detected by the detector array 2 into data for processing by the data processing module 4. Of course, the data acquisition module 3 may also be just a data acquisition line for transmitting imaging data detected by the detector array 2 to the data processing module 4 via the data acquisition line.

The data processing module 4 is used for processing the data acquired by the data acquisition module 3 and realizing the measurement of the focus of the X-ray 5 to be measured. The data processing module 4 is loaded with a data processing program, i.e. a focus data calculation program, and the data processing module 4 can be a processing chip, such as a single chip microcomputer, or a computer host, such as an upper computer. In this embodiment, the data processing module 4 is a part of the X-ray focus measuring apparatus, as another embodiment, the data processing module 4 is not a part of the X-ray focus measuring apparatus, but is an external device, so that the data acquisition module 3 has a data transmission interface (for example, a USB port), when outputting data to the data processing module 4, it is necessary that the data processing module 4 is connected to the data acquisition module 3 through the USB port, and then the data acquisition module 3 outputs the data to the data processing module 4.

For the convenience of arrangement, the measuring platform further comprises a shell 6, the detector array 2 is horizontally arranged on the upper end face of the shell 6, and the data acquisition module 3 and the data processing module 4 are arranged inside the shell 6. The shape of the housing 6 is not exclusive, such as a rectangular parallelepiped, a cylinder, and the like, and in the present embodiment, the housing 6 is a cylinder. As described in the previous paragraph, if the data processing module 4 is an external device, the USB port needs to be disposed on the side wall of the housing. In addition, as another embodiment, the measurement platform may not include the housing 6, and the detector array 2, the data acquisition module 3 and the data processing module 4 are directly and independently arranged.

As shown in fig. 3, a guide post 7 extending in the vertical direction (i.e. the vertical direction) is disposed above the measuring platform, and the guide post 7 is fixedly disposed in the vertical direction, for example, by a fixing base. The guide post 7 is provided with a slit mounting rack 8, the slit mounting rack 8 is movably assembled with the guide post along the up-down direction, and the slit 1 is fixed on the slit mounting rack 8. In order to fix the slit 1, a fixing structure, such as a fixing clip or a bolt, for fixing the slit 1 may be provided on the slit mounting bracket 8. Furthermore, the slit mount 8 may be provided with a stopper structure adapted to the structure of the guide post 7, so that the slit mount 8 can only move up and down on the guide post 7 and cannot be separated from the guide post 7. The guide post 7 can be a guide rail with a sliding groove, and the slit mounting rack 8 is provided with a sliding block or a roller movably assembled with the sliding groove; or, a lead screw arranged along the up-down direction is arranged on the guide post 7, and the slit mounting rack 8 is assembled on the lead screw to move up and down along the guide post 7 through the lead screw. Therefore, the structure and the fitting relationship of the guide post 7 and the slit mount 8 are not unique. In addition, the moving mode of the slit mounting rack 8 on the guide post 7 can be manually controlled, the slit mounting rack 8 is manually operated to realize the up-and-down movement, and of course, the slit mounting rack can also be electrically controlled, for example: be provided with drive module on slit mounting bracket 8, as shown in fig. 4, drive module includes driving motor 13, controller 12 and operation button unit 11, operation button unit 11 is including the start button, the shutdown button, move the button downwards and move the button upwards, the signal output part of operation button unit 11 connects controller 12's signal input part, driving motor 13 is connected to controller 12's signal output part, driving motor 13 is used for driving slit mounting bracket 8 to reciprocate along guide pillar 7, driving motor 13's drive mode has: the driving motor 13 drives the roller on the slit mounting rack 8 to rotate, so that the slit mounting rack 8 moves up and down. In addition, a driving motor can be arranged on the guide post 7 and drives a lead screw on the guide post 7 to rotate, and the slit mounting rack 8 can also move up and down. Of course, the drive module is powered by a battery or a power supply line.

Then, as shown in fig. 3, the slit mounting frame 8 is disposed above the measurement platform, i.e. the slit 1 is disposed above the measurement platform, the slit 1 is located between the measurement platform (i.e. the detection plane of the detector array 2, also referred to as the image plane) and the focal point, the X-ray 5 is irradiated to the slit 1 from above the slit 1, and the X-ray 5 is imaged on the detector array 2 after passing through the slit 1.

Further, in order to measure the position of the slit mounting bracket 8 on the guide post 7 (i.e. the height of the slit mounting bracket 8), a scale is arranged along the guide post 7, and the scale is carved with a scale, so that the position of the slit mounting bracket 8 can be directly obtained by reading the scale. Certainly, the guide pillar 7 can also not be provided with a scale, the scale is an external independent device, when measurement is needed, the scale is placed along the guide pillar 7, the scale is used for measurement, and when the measurement is finished, the scale is folded.

Furthermore, the slit mount 8 is provided with a fixing mechanism 9 for fixing the slit mount 8 to a position on the guide post 7. Then, after the slit mounting frame 8 is moved to the corresponding position, the slit mounting frame 8 is fixed by the fixing mechanism 9, so that the slit mounting frame 8 does not move up and down, and accurate measurement is ensured. The fixing mechanism 9 can be a bolt, and the bolt is fastened on the guide pillar 7 by rotating the bolt; the fixing means 9 can also be a clamping device like a clip; the securing mechanism 9 may also be a securing strap. Therefore, the fixing mechanism 9 is not exclusively implemented as long as its fixing function can be achieved.

The rotating mechanism 10 is arranged below the shell 6, and the rotating mechanism 10 can drive the shell 6 to rotate 360 degrees in the horizontal direction, so that the length and the width of the focus in different directions can be measured. The rotating mechanism 10 can rotate through manual operation, so that the rotating mechanism 10 can be only a rotating shaft which is coaxially arranged with the central shaft of the shell 6, and when the rotating shaft rotates, the shell 6 is driven to synchronously rotate; the rotating mechanism 10 can also be driven by a motor to rotate, and the rotating mechanism 10 further comprises a motor which drives the rotating shaft to rotate so as to drive the shell 6 to rotate. Furthermore, the rotating mechanism 10 is provided with positioning mechanisms at intervals of 90 degrees in the circumferential direction, and such positioning mechanisms that perform positioning at intervals of 90 degrees belong to the prior art, and the present embodiment will not be described in detail. Then, four positioning mechanisms are provided in total, and the length and width of the focal point in two directions orthogonal to each other can be measured by four position states when the housing 6 is rotated 360 degrees, thereby achieving accurate measurement of the focal point. In addition, a horizontal adjusting mechanism, such as three lifting and rotating screws, is disposed between the housing 6 and the rotating mechanism 10 for adjusting the level of the housing 6, i.e., the level of the detector array 2.

In addition, the X-ray focus measuring device can be further provided with a Bluetooth module, the data acquisition module 3 is connected with the Bluetooth module, the Bluetooth module is in communication connection with the mobile terminal, acquired imaging data are output to the mobile terminal, and data processing and display are achieved through the mobile terminal.

The X-ray focus measuring device measures by using the principle of a slit imaging method, namely according to the similar principle in slit imaging, as shown in figure 5, the mathematical relation of geometric parameters is as follows:

in the formula: s is an object, namely an X-ray 5 to be detected; f₁Is an image, i.e. an image imaged on the detector array 2; l is the distance between the object and the image; l is₁Is the image distance.

The basic test indexes of the X-ray focus measuring device are as follows: focal point measurement range: 0.1 mm-6.0 mm; measurement range of the eye side array: 30 mm; position resolution: 0.01 mm; repeatability: 1 percent; kilovolt: (40-150) kV; mAs range: greater than 5 mAs.

Therefore, the X-ray focus measuring device adopts a slit imaging principle, when an X-ray 5 passes through a slit 1, an image of a focus is formed on a plane of a detector array 2, the intensity of an imaging signal is collected through the detector array 2, the imaging signal of the detector array 2 is collected by a data collection module 3, relevant data conversion is carried out, and then the imaging signal is output to a data processing module 4, the data processing module 4 can calculate the length and the width of the focus according to data uploaded by the data collection module 3 and the mathematical relation, and the length and the width of the focus can be displayed through a display screen.

Two measurement procedures are given below:

the first method comprises the following steps: the measurement process is carried out for a plurality of times, and the specific process is as follows:

the first measurement process: fixing the slit 1 at a position of the guide post 7 through the slit mounting rack 8, then inputting related known parameters to the data processing module 4 (such as inputting through a keyboard), and calculating according to the mathematical relationship to obtain the length and width of the focus;

and (3) a second measurement process: moving the slit mounting rack 8 to change the position of the slit 1 on the guide post 7, so that the related parameters in the mathematical relationship are changed, and then inputting the related known parameters into the data processing module 4 to calculate the length and width of the focus;

the third measurement process: moving the slit mounting rack 8 again to change the position of the slit 1 on the guide post 7, so that each parameter in the mathematical relationship is changed, and then inputting each related known parameter to the data processing module 4 to calculate the length and width of the focus;

and by analogy, measuring for multiple times.

Finally, length and width data of a plurality of groups of focuses are obtained, and accurate focus data can be obtained by calculating an average value.

And the second method comprises the following steps: two measurement processes are carried out by two imaging methods, and the two measurement results are calculated, so that the size of the focus on the image plane of the detector array 2 can be obtained, and the influence of focus mark errors is reduced (note that when the measurement process is realized, the distances from the focus to the slit 1 and the distance from the slit 1 to the image plane need to be set to be equal on measurement software, and the assumed distances from the focus to the slit 1 and the distance from the slit 1 to the image plane need to be manually input). The actual size and position of the focal spot is calculated by inversion. The double imaging method is a conventional method and is not described in detail herein.

Therefore, the advancement and innovation of the X-ray focus measuring device are as follows:

1. the detector array distribution is set to be step distribution, so that the position resolution is improved and reaches 10 mu m. The response sensitivity of the sensors in the detector array under weak signals is improved, and the method is suitable for focus slit imaging of an X-ray machine.

2. The rotating mechanism can rotate 360 degrees, a positioning mechanism is arranged every 90 degrees, the positioning mechanism is automatically positioned and used for measuring the length and the width of the focus in two mutually orthogonal directions, and the test of the length and the width direction of the focus of the X-ray machine is completed.

3. Increase in detection limit of exposure (mAs): the detection limit of the exposure (mAs) is increased to 5mAs, the exposure is reduced, and the environmental radiation is reduced.

4. The measurement range is expanded: the measurement range is expanded to 30mm, and the device can adapt to the focal size of 0.1 mm-6 mm. Even if the image of the focal point is deviated in the light field, the range of the focal point imaging can be completely covered. The measurement range is 30mm which is far larger than the existing measurement range of 0.1 mm-5 mm, and the requirement on the slit positioning can be effectively reduced.

Table 1 shows a comparison table between the conventional measuring device and the X-ray focus measuring device provided by the present application, except for a slight difference in the kilovolt range, other indexes are all improved, and the X-ray focus measuring device has outstanding advantages in the aspects of focus measuring range, exposure, theoretical calculation of the true size of the equivalent focus, and real-time data acquisition.

TABLE 1

Claims (10)

1. An X-ray focus measuring device is characterized by comprising a measuring platform and a slit, wherein a guide pillar extending in the vertical direction is arranged above the measuring platform, a slit mounting rack is arranged on the guide pillar, the slit mounting rack is movably assembled with the guide post along the up-down direction, the slit is fixed on the slit mounting rack, the measuring platform comprises a detector array and a data acquisition module, the detector array is used for detecting an image formed by the X-ray to be measured passing through the slit, the signal output end of the detector array is connected with the signal input end of the data acquisition module, the data acquisition module is used for acquiring data detected by the detector array, the signal output end of the data acquisition module is used for connecting the data processing module, and processing the data acquired by the data acquisition module to realize the measurement of the focus of the X-ray to be measured.

2. The X-ray focal point measurement device of claim 1, wherein the slit is a tungsten alloy slit.

3. The X-ray focus measuring device according to claim 1, wherein a driving module for driving the slit mounting frame to move up and down along the guide post is disposed on the slit mounting frame, the driving module includes a driving motor, a controller, and an operation button unit, the operation button unit includes a power-on button, a power-off button, a downward movement button, and an upward movement button, a signal output end of the operation button unit is connected to a signal input end of the controller, a signal output end of the controller is connected to the driving motor, and the driving motor is used for driving the slit mounting frame to move up and down along the guide post.

4. The X-ray focus measuring apparatus according to claim 1, wherein a scale is provided along the guide pillar.

5. The X-ray focus measuring apparatus according to claim 1, wherein a fixing mechanism for fixing the slit mount at a position on the guide post is provided on the slit mount.

6. The X-ray focus measurement device of claim 1, wherein the measurement platform further comprises a housing, the detector array is horizontally disposed on an upper end surface of the housing, and the data acquisition module is disposed inside the housing.

7. The X-ray focus measuring device of claim 6, wherein a rotating mechanism for rotating the housing in a horizontal direction is disposed below the housing.

8. The X-ray focus measuring device of claim 7, wherein the rotating mechanism is provided with a positioning mechanism every 90 degrees in a circumferential direction.

9. The X-ray focus measurement apparatus of claim 1, wherein the measurement platform further comprises the data processing module.

10. The X-ray focus measurement device of claim 7, wherein a horizontal adjustment mechanism is disposed between the housing and the rotation mechanism.

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