Control method and apparatus for tube current modulation of narrow-pulse x-ray source

Abstract

Disclosed in the present invention are a control method and apparatus for tube current modulation of a narrow pulse X-ray source. The control method comprises the following steps: setting a target tube current value of a primary sequential exposure; performing calculation by means of a baseline filament correction algorithm, so as to obtain a baseline filament current of the primary sequential exposure; performing primary exposure, and collecting, during the primary exposure, X-ray-source tube current sampling data, brightness data of dose feedback detection, and attenuation map information data; and for a secondary exposure and following exposures, separately adjusting and setting, on the basis of the data collected during the preceding exposure, the target tube current value, baseline filament current and filament compensation current for the present exposure, and then performing the present exposure. Thus, the accurate modulation and outputting of a tube current are implemented, thereby satisfying requirements of a CT system for tube current modulation.

Description

A control method and device for narrow-pulse X-ray source tube current modulation Technical Field

[0001] This invention relates to a control method for narrow-pulse X-ray source tube current modulation, and also to a corresponding control device, belonging to the field of radiation imaging technology. Background Technology

[0002] In existing technologies, X-rays in a CT (Computed Tomography) system are generated and emitted by an X-ray tube (also called a X-ray tube, which, together with a high-voltage generator, constitutes the X-ray source). By applying a filament current to the cathode filament of the X-ray tube to heat it, when the temperature reaches a certain level, active electrons on the cathode filament, under a high electric field environment, overflow and bombard the anode target disk of the X-ray tube, generating X-rays. The process of electron overflow to the anode is characterized by the tube current (also called mA current). During the X-ray source exposure process, with a constant electric field strength, the density of overflowing electrons is changed by adjusting the filament current applied to the cathode filament, thus changing the number of emitted electrons. This is characterized by the adjustment of the tube current, thereby changing the radiation dose of the CT system. Typically, there is a thermal hysteresis process in the change of filament temperature caused by the change in filament current. Traditional X-ray sources can generate continuous X-rays ranging from hundreds of milliseconds to tens of seconds. On the one hand, this provides sufficient time to react to filament temperature changes; on the other hand, the continuous current output facilitates closed-loop regulation of the tube current, easily meeting the tube current modulation requirements of the CT system. For narrow pulse X-ray sources used in static CT systems, which require narrow pulse sequence exposures of 500 microseconds to a few milliseconds, the impact of thermal hysteresis of the filament cannot be ignored. The poor closed-loop regulation effect of the tube current in a short time leads to poor tube current accuracy and controllability, making it difficult to meet the tube current modulation requirements of CT systems. Summary of the Invention

[0003] The primary technical problem to be solved by this invention is to provide a control method for narrow pulse X-ray source tube current modulation.

[0004] Another technical problem to be solved by the present invention is to provide a control device for narrow pulse X-ray source tube current modulation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] According to a first aspect of the present invention, a method for controlling narrow-pulse X-ray source tube current modulation is provided, comprising the following steps:

[0007] (100) Perform tube current modulation on the first exposure of the sequence, including the following sub-steps:

[0008] (1) Set the target value of the tube current for the first exposure of the sequence;

[0009] (2) Based on the target value of the tube current in the first exposure of the sequence, the basic filament current in the first exposure of the sequence is calculated by the basic filament correction algorithm;

[0010] (3) The filament base current of the first exposure of the filament loading sequence is exposed for the first time. At the same time, the current sampling data of the X-ray source tube, the brightness data of the dose feedback detection and the attenuation map information data of the first exposure are collected.

[0011] (200) Modulate the tube current for the second and subsequent exposures of the sequence, including the following sub-steps:

[0012] (4) Based on the sampling data of the X-ray source tube current of the previous exposure and the brightness data of the dose feedback detection, as well as the correspondence between the two, error analysis calculation is performed to obtain the error correction coefficient;

[0013] (5) Based on the attenuation map information data from the previous exposure and the relationship between the tube current and the attenuation map information data, set the target value of the tube current for this exposure;

[0014] (6) The target value of the tube current in this exposure is corrected using the error correction coefficient to obtain the corrected target value of the tube current; then the basic filament current of this exposure is calculated using the basic filament correction algorithm.

[0015] (7) Calculate the tube current difference obtained by subtracting the tube current corresponding to the attenuation map information data of the previous exposure from the tube current target value of the current exposure, and judge the tube current difference; when the tube current difference is not equal to zero, proceed to step (8); when the tube current difference is equal to zero, proceed to step (9).

[0016] (8) Based on the tube current difference, find the difference coefficient and adjustment time table to obtain the filament current compensation coefficient and compensation output time coefficient, and calculate the filament compensation current and filament compensation time for this exposure; then proceed to step (10);

[0017] (9) The filament base current, filament compensation current and filament compensation time of the previous exposure are used as the filament base current, filament compensation current and filament compensation time of this exposure.

[0018] (10) The base current of the filament and the compensation current of the filament in this exposure are superimposed and applied to the filament for this exposure; at the same time, the current sampling data of the X-ray source tube, the brightness data of the dose feedback detection and the attenuation map information data of this exposure are collected.

[0019] (11) Repeat steps (4) to (10) until the last exposure of the sequence exposure, and then proceed to the next step;

[0020] (12) Narrow pulse sequence exposure ends.

[0021] Preferably, in step (2), the calculation of the filament base current during the first exposure of the sequence satisfies the following formula: f1=λ1*I 2 +λ2*I+I0

[0022] Where f1 is the filament base current of the first exposure of the sequence, λ1 is the coefficient of the quadratic term of the polynomial fitting, λ2 is the coefficient of the linear term of the polynomial fitting, I is the target value of the tube current, and I0 is the constant term of the polynomial fitting.

[0023] Preferably, in step (4), the calculation of the error correction coefficient satisfies the following formula: k i =a1 / a2

[0024] Where, k i denoted by error correction coefficient, i represents the sequence number of this exposure; a1 is the X-ray source tube current sampling data of the previous exposure, and a2 is the tube current value corresponding to the brightness data of the dose feedback detection of the previous exposure.

[0025] Preferably, in step (6), the calculation of the filament base current disclosed in this study satisfies the following formula: f i =λ1*(I x ) 2 +λ2*I x +I0

[0026] Among them, f i This indicates the filament base current exposed in this instance, and i represents the sequence number of this exposure; I x λ1 represents the target value of the tube current after this exposure correction; λ2 represents the coefficients of the quadratic term of the polynomial fitting; and I0 represents the constant term of the polynomial fitting.

[0027] Preferably, in step (8), when the tube current difference is greater than zero, the filament compensation current Ic exposed in this study... i and the filament compensation time Tc i The calculation satisfies the following formula: Ic i =p*(Ith_h) Tc i =v*Te

[0028] Where p is the filament current compensation coefficient corresponding to the difference in positive tube current, v is the compensation output time coefficient, Ith_h is the high threshold for fixed fluctuation of filament current, and Te is the exposure time for this exposure.

[0029] Preferably, in step (8), when the tube current difference is less than zero, the filament compensation current Ic exposed in this study... i and the filament compensation time Tc i The calculation satisfies the following formula: Ic i =n*(Ith_l) Tc i =v*Te

[0030] Where n is the filament current compensation coefficient corresponding to the negative tube current difference, v is the compensation output time coefficient, Ith_l is the low threshold for fixed fluctuation of filament current, and Te is the exposure time of this exposure.

[0031] According to a second aspect of the present invention, a control device for narrow-pulse X-ray source tube current modulation is provided, comprising a processor and a memory, wherein the processor and the memory are coupled together; wherein,

[0032] The memory is used to store computer programs;

[0033] The processor is used to run a computer program stored in the memory to execute the above-described narrow-pulse X-ray source tube current modulation control method.

[0034] Compared with existing technologies, the narrow-pulse X-ray source tube current modulation control method provided by this invention uses relevant data acquired from the previous exposure to set and adjust the tube current and filament current for the next exposure. In sequential exposures, each exposure pulse is automatically pre-set in advance, achieving precise tube current modulation and output, thereby meeting the tube current modulation requirements of CT systems. Therefore, the narrow-pulse X-ray source tube current modulation control method provided by this invention has beneficial effects such as good controllability of tube current output, high accuracy, and excellent closed-loop adjustment effect in a short time. Attached Figure Description

[0035] Figure 1 is a flowchart of a narrow pulse X-ray source tube current modulation control method provided in an embodiment of the present invention;

[0036] Figure 2 is a schematic diagram of a narrow pulse X-ray source tube current modulation control device provided in an embodiment of the present invention. Detailed Implementation

[0037] The technical content of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] To facilitate understanding and explanation, we will first briefly introduce the concept of "narrow pulse sequence exposure" provided by a narrow pulse X-ray source. Narrow pulse sequence exposure, also known as a narrow exposure pulse sequence, is a time-ordered distribution of a set of narrow pulses. It represents the tube current (mA) capable of generating X-rays, and the first exposure in the sequence indicates that the X-ray source emits the first narrow pulse of X-ray. The width, tube current, and time interval of each narrow pulse in the sequence can be the same or different. By adjusting and designing the narrow pulse sequence exposure, the radiation dose of the CT system can be changed, thereby obtaining specific image information to optimize image contrast and clarity.

[0039] As shown in Figure 1, the control method for narrow pulse X-ray source tube current modulation provided by an embodiment of the present invention includes at least the following steps:

[0040] S100: Perform tube current modulation on the first exposure of the sequence, including the following sub-steps:

[0041] S1: Set the target value of the tube current for the first exposure of the sequence.

[0042] The CT system sets the target value of the tube current for the first exposure of the sequence based on the radiation dose required for the mission.

[0043] S2: Based on the target value of the tube current during the first exposure of the sequence, the basic filament current during the first exposure of the sequence is calculated using the basic filament correction algorithm.

[0044] In one embodiment of the present invention, the basic filament correction algorithm includes at least the following sub-steps: For each voltage level from 70 to 140 kV (in 10 kV increments), the filament current is gradually increased from its lowest value in fixed increments to train the tube. The tube current data corresponding to the filament current at each voltage level is recorded, a tube current / filament current curve is plotted, and polynomial fitting is performed on this data. Simultaneously, the coefficient of determination of the fitting effect is analyzed. When the coefficient of determination is ≥ 0.5, the fitting formula is accepted; when the coefficient of determination is < 0.5, the area with a large fitting error is fitted piecewise to improve the fitting reliability. Through the above operations, the formula for calculating the basic filament current can be obtained. When a target value for the tube current at a certain voltage level is set, this formula can be used to calculate the filament current required for that operating condition, i.e., the basic filament current.

[0045] For example, after processing with the basic filament correction algorithm, the formula for calculating the basic filament current f1 for the first exposure of the sequence is as follows: f1=λ1*I 2 +λ2*I+I0 (1)

[0046] Where λ1 is the coefficient of the quadratic term in the polynomial fitting, λ2 is the coefficient of the linear term in the polynomial fitting, I is the target value of the tube current, and I0 is the constant term in the polynomial fitting.

[0047] S3: The filament base current of the first exposure of the filament loading sequence is used for the first exposure. At the same time, the sampling data of the X-ray source tube current, the brightness data of the dose feedback detection, and the attenuation map information data of the first exposure are collected.

[0048] The initial exposure of the X-ray source tube current sampling data is collected by the X-ray source device, while the brightness data and attenuation map information data of the dose feedback detection are collected by the CT system. The collected data will be used to modulate the tube current of the next exposure in the sequence exposure to form an advanced preset scheme for each exposure pulse during the narrow pulse sequence exposure process.

[0049] S200: Perform tube current modulation on the second exposure and subsequent exposures of the sequence, including the following sub-steps:

[0050] S4: Based on the sampling data of the X-ray source tube current from the previous exposure and the brightness data from the dose feedback detection, as well as the correspondence between the two, error analysis is performed to calculate the error correction coefficient k.

[0051] The tube current feedback link of the X-ray source uses a linear sampling mechanism. After obtaining the tube current sampling data and dose feedback detection data, the X-ray source control system can linearly correct the sampling ratio of its internal tube current. Assuming the tube current sampling data from the previous exposure is a1, and the tube current value corresponding to the brightness data detected by dose feedback is a2, then the error correction coefficient k... i For: k i =a1 / a2 (2)

[0052] Where i represents the sequence number of this exposure.

[0053] S5: Based on the attenuation map information data from the previous exposure and the relationship between tube current and attenuation map information data, set the target value of tube current for this exposure of the X-ray source.

[0054] The CT system uses the attenuation map data from the previous exposure and calculates the required tube current value for the next exposure based on the relationship between tube current and attenuation map data. This tube current target value is then set. Subsequently, the required filament current for the X-ray source can be determined based on the target tube current value from this exposure.

[0055] S6: The target value of tube current for this exposure is corrected using the error correction coefficient k to obtain the corrected target value of tube current; then the basic filament current for this exposure is calculated using the basic filament correction algorithm.

[0056] Assume the corrected target tube current value is I. x The filament base current f exposed this time i The calculation formula is as follows: f i =λ1*(I x ) 2 +λ2*I x +I0 (3)

[0057] Among them, f i The filament base current is represented by i, which represents the sequence number of this exposure; λ1 is the coefficient of the quadratic term of the polynomial fitting, λ2 is the coefficient of the linear term of the polynomial fitting, I is the target value of the tube current, and I0 is the constant term of the polynomial fitting.

[0058] S7: Calculate the tube current difference obtained by subtracting the tube current corresponding to the attenuation map information data of the previous exposure from the target tube current value of this exposure, and judge the tube current difference; when the tube current difference is not equal to zero, proceed to step S8; when the tube current difference is equal to zero, proceed to step S9.

[0059] S8: Based on the tube current difference, find the difference coefficient and adjustment schedule to obtain the filament current compensation coefficient and compensation output time coefficient, and calculate the filament compensation current and filament compensation time for this exposure; then proceed to step S10.

[0060] The calculation of filament compensation current and filament compensation time in step S8 includes two cases:

[0061] The first scenario: When the tube current difference is greater than zero, the filament compensation current Ic exposed in this case... i and filament compensation time Tc i The calculation is as follows: Ic i =p*(Ith_h) (4) Tc i =v*Te (5)

[0062] Where p is the filament current compensation coefficient corresponding to the difference in positive tube current, v is the compensation output time coefficient, Ith_h is the high threshold for fixed fluctuation of filament current, and Te is the exposure time for this exposure.

[0063] The difference coefficient and adjustment time table is a table showing the correspondence between the output positive (negative) tube current difference and the filament current compensation coefficient and compensation output time coefficient when the system corrects the filament base current for the first exposure of the sequence using the basic filament correction algorithm. By looking up the table and making calculations, the filament compensation current and its compensation output time can be obtained, serving as the compensation scheme for the filament current in this exposure. The setting of the fixed high threshold for filament current fluctuation is usually based on the filament life curve, selecting a larger value within the safe range of filament life as the fixed high threshold. For example, if the operating range of the filament current is 6A, based on the filament life curve and the safe range (0.95), the fixed high threshold for filament current fluctuation is selected as 5.7A.

[0064] The second scenario: When the tube current difference is less than zero, the filament compensation current Ic exposed in this case... i The calculation is as follows: Ic i =n*(Ith_l) (6)

[0065] Where n is the filament current compensation coefficient corresponding to the negative tube current difference, and Ith_l is the low threshold for fixed fluctuation of filament current.

[0066] Filament compensation time Tc i Formula (5) is still used for calculation. The low threshold for fixed fluctuation of filament current is usually set to be less than or equal to the preheating current value. For example, the low threshold for fixed fluctuation of filament current is set to 2.5A.

[0067] S9: Use the filament base current, filament compensation current, and filament compensation time from the previous exposure as the filament base current, filament compensation current, and filament compensation time for this exposure.

[0068] When the tube current difference is zero, it indicates that the tube current output is accurate and no readjustment is needed. The parameter settings for this exposure can be the same as those for the previous exposure. It should be noted that if the previous exposure was the first exposure in the sequence, both the filament compensation current and the filament compensation time are zero.

[0069] The steps S4 to S9 above are mainly the process of setting and adjusting the tube current and filament current for this exposure based on the relevant data collected in the previous exposure.

[0070] S10: The base current of the filament and the compensation current of the filament for this exposure are superimposed and applied to the filament for this exposure; at the same time, the current sampling data of the X-ray source tube, the brightness data of the dose feedback detection, and the attenuation map information data of this exposure are collected.

[0071] S11: Repeat steps S4 to S10 until the last exposure of the sequence exposure, and then proceed to the next step.

[0072] The second exposure and subsequent exposure sequences execute steps S4 to S10, allowing the system to individually adjust and control each exposure pulse in advance. It should be noted that the filament compensation current loading time is only the duration of the compensation output time, which is less than or equal to the exposure time of this exposure. The exposure time is the same as the filament base current loading time.

[0073] S12: Narrow pulse sequence exposure ends.

[0074] The steps of the narrow pulse X-ray source tube current modulation control method provided in the embodiments of the present invention have been described in detail above. By performing advance preset adjustment on each exposure pulse in the narrow pulse sequence exposure process through the above steps, accurate control of the tube current is achieved to meet the requirements of narrow pulse X-ray source tube current modulation.

[0075] The following example, illustrating the control method for the current modulation of the narrow-pulse X-ray source tube, is further explained through a narrow-pulse sequence exposure process in an application scenario.

[0076] For example, in a certain application scenario, a narrow-pulse X-ray source needs to perform sequential exposures at a voltage level of 120kV. The parameters for the first exposure in the sequence are as follows: target tube current of 180mA, exposure time of 1.3ms, and interval time of 16ms. The relevant information for starting the X-ray source system is set accordingly. Furthermore, based on the filament's operating parameters, the high threshold for fixed filament current fluctuation is set to 5.7A, and the low threshold for fixed filament current fluctuation is set to 2.5A. The control process for the narrow-pulse X-ray source tube current modulation is as follows.

[0077] S101: Set the target value of the tube current for the first exposure of the sequence to 180mA.

[0078] The CT system sets the target tube current value for the first exposure of the X-ray source device according to the radiation dose required for the mission.

[0079] S102: Based on the target tube current of 180mA for the first exposure of the sequence, the basic filament current f1 for the first exposure of the sequence at a voltage level of 120kV is calculated using the basic filament correction algorithm and the aforementioned formula (1) as follows: f1=-0.000045*180 2 +0.016563*180+3.894685=5.418025A;

[0080] Where -0.000045 is the coefficient of the quadratic term in the polynomial fitting, 0.016563 is the coefficient of the linear term in the polynomial fitting, and 3.894685 is the constant term in the polynomial fitting.

[0081] S103: The filament base current of the first exposure of the filament loading sequence is 5.418A. At the same time, the X-ray source device collects the X-ray source tube current of 179mA for the first exposure. The CT system collects the brightness data and attenuation map information data of the dose feedback detection. The tube current value corresponding to the dose feedback brightness data collected by the CT system is 174mA.

[0082] The following is the operation process exposed for the second time:

[0083] S104: Based on the X-ray source tube current sampling data of 179mA from the previous exposure and the brightness data from the dose feedback detection, as well as the correspondence between the two, an error analysis was performed, and the error correction coefficient k1 was obtained as: k1=a1 / a2=179 / 174=1.0287;

[0084] Where a1 is the sampling data of the X-ray source tube current, and a2 is the tube current value corresponding to the brightness data detected by dose feedback.

[0085] S105: The CT system sets the target value of the tube current for the current exposure of the X-ray source based on the attenuation map information data from the previous exposure and the relationship between the tube current and the attenuation map information data.

[0086] The CT system uses the attenuation map information data from the previous exposure projection to calculate the tube current value required for the next exposure projection, which is 170mA, according to the relationship between the tube current and the attenuation map information data. In other words, the target tube current value for this exposure of the X-ray source is set to 170mA.

[0087] S106: The target tube current value for this exposure is corrected using the error correction coefficient k1, resulting in a modified target tube current value of 174.879 mA. Using the basic filament correction algorithm, the basic filament current f2 for this exposure sequence at a 120 kV voltage level is calculated as follows: f2 = -0.000045 * 174.879 2 +0.016563*174.879+3.894685=5.415A;

[0088] S107: Subtracting the tube current of 174mA corresponding to the attenuation map data from the previous exposure from the target tube current value of 170mA for this exposure, the tube current difference is -4mA. This tube current difference is less than zero. Therefore, the filament compensation current and filament compensation time need to be calculated according to the second case in step S8 above.

[0089] S108: Based on the tube current difference of -4mA, find the difference coefficient and adjustment time table (see Table 1). The filament current compensation coefficient corresponding to the negative tube current difference is 1.0 and the compensation output time coefficient is 0.1. The filament compensation current Ic2 and filament compensation time Tc2 for this exposure are calculated as follows: Ic2 = 1.0 * 2.5 = 2.5A Tc2 = 0.1 * 1.3 = 0.13ms

[0090] Wherein, 2.5A is the low threshold for fixed fluctuation of filament current, and 1.3ms is the exposure time for this exposure. Then proceed to step S110.

[0091] Table 1. Difference coefficients and adjustment schedules for 120kV levels.

[0092] It should be noted that Table 1 only lists the coefficients for negative tube current differences and does not include data for positive tube current differences. Furthermore, to further improve the accuracy of compensation, the difference coefficients and adjustment time schedule can be formulated as a matrix table with a smaller scale. For example, negative tube current differences within the range of -20mA to 0 can be divided into six or more intervals, listing the corresponding filament current compensation coefficients and filament current compensation time coefficients for each interval. Real-time data analysis can also be used to introduce a closed loop during the table's reference.

[0093] S110: The base filament current of 5.415A (exposure time of 1.3ms) and the filament compensation current of 2.5A (filament compensation time of 0.13ms) for this exposure are superimposed and applied to the filament for this exposure; at the same time, the X-ray source device collects the X-ray source tube current sampling data for this exposure, and the CT system collects the brightness data and attenuation map information data of the dose feedback detection.

[0094] S111: Repeat steps S104 to S110 until the last exposure of the sequence exposure, and then proceed to the next step.

[0095] S112: Narrow pulse sequence exposure ends.

[0096] It should be noted that in the subsequent sequence exposure process, if the tube current difference calculated in step S107 of a certain sequence exposure is greater than zero, step 108 will be replaced by the first case of step S8 in the aforementioned method; if the tube current difference calculated in step S107 is equal to zero, step 108 will be replaced by step S10 in the aforementioned method.

[0097] As can be seen from the above embodiments, the narrow pulse X-ray source tube current modulation control method provided by the present invention, in sequential exposure, uses relevant data collected from the previous exposure to separately set and adjust the tube current and filament current for the next exposure, thereby achieving precise tube current modulation and output.

[0098] Based on the above-described control method for narrow-pulse X-ray source tube current modulation, this embodiment of the invention further provides a control device for narrow-pulse X-ray source tube current modulation, as shown in FIG2. The control device includes one or more processors and a memory. The memory is coupled to the processors and is used to store one or more computer programs. When one or more computer programs are executed by one or more processors, the one or more processors implement the control method for narrow-pulse X-ray source tube current modulation as described in the above embodiment.

[0099] The processor controls the overall operation of the control device to complete all or part of the steps of the narrow-pulse X-ray source tube current modulation control method described above. This processor module can be a central processing unit (CPU), graphics processing unit (GPU), field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), digital signal processing (DSP) chip, etc. The memory stores various types of data to support the operation of the control device. This data may include, for example, instructions for any application or method used to operate the control device, as well as application-related data. The memory module can be implemented using any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, etc.

[0100] In summary, compared with existing technologies, the narrow-pulse X-ray source tube current modulation control method provided by this invention uses relevant data acquired from the previous exposure to set and adjust the tube current and filament current for the next exposure. This allows for automatic advance pre-setting of each exposure pulse during sequential exposure, achieving precise tube current modulation and output, thus meeting the tube current modulation requirements of CT systems. Therefore, the narrow-pulse X-ray source tube current modulation control method provided by this invention has beneficial effects such as good controllability of tube current output, high accuracy, and excellent closed-loop adjustment effect in a short time.

[0101] The control method and apparatus for narrow-pulse X-ray source tube current modulation provided by the present invention have been described in detail above. Any obvious modifications made by those skilled in the art without departing from the essence of the present invention will constitute an infringement of the patent rights of the present invention and will incur corresponding legal liability.

Claims

1. A method of controlling the modulation of tube current for a narrow-pulse radiation source, characterized by Includes the following steps: (100) Perform tube current modulation on the first exposure of the sequence, including the following sub-steps: (1) Set the target value of the tube current for the first exposure of the sequence; (2) Based on the target value of the tube current in the first exposure of the sequence, the basic filament current in the first exposure of the sequence is calculated by the basic filament correction algorithm; (3) The filament base current of the first exposure of the filament loading sequence is exposed for the first time. At the same time, the current sampling data of the X-ray source tube, the brightness data of the dose feedback detection and the attenuation map information data of the first exposure are collected. (200) Modulate the tube current for the second and subsequent exposures of the sequence, including the following sub-steps: (4) Based on the sampling data of the X-ray source tube current of the previous exposure and the brightness data of the dose feedback detection, as well as the correspondence between the two, error analysis calculation is performed to obtain the error correction coefficient; (5) Based on the attenuation map information data from the previous exposure and the relationship between the tube current and the attenuation map information data, set the target value of the tube current for this exposure; (6) The target value of the tube current exposed in this exposure is corrected using the error correction coefficient to obtain the corrected target value of the tube current. Then, the basic filament current of this exposure sequence is calculated using the basic filament correction algorithm; (7) Calculate the tube current difference obtained by subtracting the tube current corresponding to the attenuation map information data of the previous exposure from the tube current target value of the current exposure, and judge the tube current difference; when the tube current difference is not equal to zero, proceed to step (8); when the tube current difference is equal to zero, proceed to step (9). (8) Based on the tube current difference, find the difference coefficient and adjustment time table to obtain the filament current compensation coefficient and compensation output time coefficient, and calculate the filament compensation current and filament compensation time for this exposure; then proceed to step (10); (9) The filament base current, filament compensation current and filament compensation time of the previous exposure are used as the filament base current, filament compensation current and filament compensation time of this exposure. (10) The base current of the filament and the compensation current of the filament in this exposure are superimposed and applied to the filament for this exposure; at the same time, the current sampling data of the X-ray source tube, the brightness data of the dose feedback detection and the attenuation map information data of this exposure are collected. (11) Repeat steps (4) to (10) until the last exposure of the sequence exposure, and then proceed to the next step; (12) Narrow pulse sequence exposure ends.

2. The control method for narrow-pulse X-ray source tube current modulation as described in claim 1, characterized in that... In step (2), the basic filament correction algorithm includes the following sub-steps: At the preset electric field voltage level, the filament current is gradually increased from the lowest value of the filament current in a fixed increment to carry out tube training. The tube current data corresponding to the filament current at each voltage level is recorded, the tube current / filament current curve is plotted, and polynomial fitting is performed on the tube current data. Analyze the coefficient of determination of the fit; when the coefficient of determination is ≥0.5, the fit formula is accepted. When the coefficient of determination is less than 0.5, the region with the largest fitting error is fitted in a piecewise manner to improve the fitting reliability.

3. The control method for narrow-pulse X-ray source tube current modulation as described in claim 2, characterized in that... In step (2), the calculation of the filament base current for the first exposure of the sequence satisfies the following equation: f1 = λ1 * I 2 + λ2 * I + I0 Where f1 is the filament base current of the first exposure of the sequence, λ1 is the coefficient of the quadratic term of the polynomial fitting, λ2 is the coefficient of the linear term of the polynomial fitting, I is the target value of the tube current, and I0 is the constant term of the polynomial fitting.

4. The method of claim 1, wherein the pulse width is less than 100 ns. In step (4), the calculation of the error correction coefficient satisfies the following formula: k i = a1 / a2 wherein k i represents the error correction coefficient, i represents the sequence number of the current exposure; a1 is the tube current sampling data of the previous exposure, and a2 is the tube current value corresponding to the brightness data of the dose feedback detection of the previous exposure.

5. The method of claim 1, wherein the pulse width is less than 100 ns. In step (6), the calculation of the filament base current for the present exposure satisfies the following equation: f i = λ1 * (I x ) 2 + λ2 * I x + I0 Wherein, f i represents the filament base current of this exposure, i represents the sequence number of this exposure; I x is the tube current target value after correction for this exposure; λ1 is the quadratic term coefficient of polynomial fitting, λ2 is the linear term coefficient of polynomial fitting, and I0 is the constant term of polynomial fitting.

6. The method of controlling narrow pulse x-ray source tube current modulation of claim 1, wherein In step (8), when the tube current difference is greater than zero, the filament compensation current Ic for the present exposure i and the calculation of the filament compensation time Tc i satisfies the following formula: Ic i = p * (Ith h) Tc i = v * Te Where p is the filament current compensation coefficient corresponding to the difference in positive tube current, v is the compensation output time coefficient, Ith_h is the high threshold for fixed fluctuation of filament current, and Te is the exposure time for this exposure.

7. The method of controlling the tube current modulation of a narrow pulse radiation source of claim 1, wherein In step (8), when the tube current difference is less than zero, the filament compensation current Ic for the present exposure i and the filament compensation time Tc i are calculated to satisfy the following formulae: Ic i = n * (Ith_l) Tc i = v * Te Where n is the filament current compensation coefficient corresponding to the negative tube current difference, v is the compensation output time coefficient, Ith_l is the low threshold for fixed fluctuation of filament current, and Te is the exposure time of this exposure.

8. A control device for narrow pulse x-ray source tube current modulation, characterized in that It includes a processor and a memory, wherein the processor and the memory are coupled; wherein, The memory is used to store computer programs; The processor is used to run a computer program stored in the memory to execute the narrow pulse X-ray source tube current modulation control method as described in any one of claims 1 to 7.

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