A dose modulation method and system under rapid kilovolt switching

Abstract

This application belongs to the field of CT scanning technology. A dose modulation method under rapid kilovolt switching divides the circumferential data acquisition angle of CT energy spectrum imaging scans into multiple high- and low-energy integration time groups, obtaining multiple integration time groups at various angles. Based on the high- and low-energy integration time groups at specific angles, the signal intensity required for the average patient body size is determined. Based on the signal intensity required for the average patient body size and the difference in body size distribution between the current patient and the current patient, the signal intensity is adjusted to obtain the signal intensity required for the current patient at a specific angle. With a fixed total integration time and balanced high- and low-energy intensities, the high- and low-energy time ratio is adjusted according to the signal intensity required for the current patient at a specific angle, obtaining the high- and low-energy exposure time at that specific angle. This achieves the goal of maintaining a constant current while controlling the dose difference requirements and corresponding differences for different body sizes by adjusting the high- and low-energy time ratios at specific angles.

Description

Technical Field

[0001] This application belongs to the field of CT scanning technology, and in particular relates to a dose modulation method and system under rapid kilovolt switching. Background Technology

[0002] CT spectral (dual-energy) imaging scanning with rapid kilovolt (kV) switching mode is a very representative spectral scanning mode. Since the switching of kilovolts is the basis of the function in this mode, the modulation of tube current is very difficult to implement in hardware, and the traditional tube current (milliampere) modulation scheme based on the difference in body size distribution is limited.

[0003] In view of this, this application proposes a dose modulation method and system for rapid kilovolt switching based on circumferential modulation of human body shape information. Summary of the Invention

[0004] Therefore, it is necessary to provide a dose modulation method under rapid kilovolt switching to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a dose modulation method under rapid kilovolt switching, the method comprising:

[0006] The circumferential data acquisition angle of CT energy spectrum imaging scan is divided into multiple high and low energy integration time groups to obtain multiple integration time groups under multiple angles.

[0007] Based on the high and low energy integration time group at a specific angle, the signal intensity required to determine the average body size of the patient is determined, wherein the specific angle refers to any angle among multiple angles;

[0008] Based on the signal strength required for the average body size of the patient and the difference in body size distribution of the current patient, the signal strength is adjusted to obtain the signal strength required for the current patient at the specific angle;

[0009] With a fixed total integration time and balanced high and low energy intensities, the time ratio of high and low energies is adjusted according to the signal intensity required by the patient at the specific angle to obtain the high and low energy exposure times at the specific angle. Here, "high" and "low" energies refer to the sum of the weighted high-energy spectrum and the sum of the weighted low-energy spectrum, given that both are known.

[0010] The weighted energy sum ρ of the high energy spectrum H Represented as:

[0011] ρ H =∑(S H (E)*E);

[0012] The weighted energy sum ρ of the low energy spectrum L Represented as:

[0013] ρ L =∑(S L (E)*E);

[0014] Among them, S H , representing the high-energy X-ray spectral distribution function, S L , represents the low-energy X-ray energy spectrum distribution function, and E, represents the X-ray photon energy.

[0015] In some feasible methods, the step of dividing the circumferential data acquisition angle of CT energy spectral imaging scan into multiple high- and low-energy integration time groups to obtain multiple integration time groups at multiple angles includes:

[0016] The circumferential data acquisition angle of CT energy spectral imaging scan is divided into n equally divided high and low energy integration time groups T, resulting in n integration time groups at each angle. The calculation formula for the integration time group at each angle is as follows:

[0017]

[0018] Where T represents the total integration time of the high-energy and low-energy times corresponding to each angular interval, and b represents the number of equal divisions of the circumference.

[0019] In some feasible methods, the step of determining the signal intensity required for the average patient body size based on the high and low energy integration time set at a specific angle includes:

[0020] The formula for calculating the integral time set at each specific angle θ is:

[0021] T = T h (θ)+T l (θ);

[0022] Among them, t h , representing the dynamically adjusted high-energy integration time, t l , represents the low-energy integration time after dynamic adjustment, and θ represents the circumferential acquisition angle;

[0023] The formula for calculating the signal strength required for the average patient body size is:

[0024] I base =T H *ρ H +T L *ρ L ;

[0025] Among them, I base ρ represents the signal strength required for the average body size of the patients. H ρ represents the weighted sum of energies in the high-energy spectrum. L T represents the weighted sum of the low-energy spectrum energies. H, representing the baseline high-energy integration time, T L , representing the baseline low-energy integration time.

[0026] In some feasible methods, the step of adjusting the signal strength based on the difference between the signal strength required for the average body size of the patient and the current body size distribution of the patient, to obtain the signal strength required for the current patient at the specific angle, includes:

[0027] The formula for calculating the signal strength required by the current patient at the specified angle is as follows:

[0028]

[0029] I base =T H *ρ H +T L *ρ L =(TT) L )*ρ H +T L *ρ L ;

[0030] Where I(θ) represents the signal strength required by the current patient at the current angle θ, u represents the adjustment coefficient, and d(θ) represents the patient's body shape parameters at the current angle θ. This represents the average body size parameter.

[0031] In some feasible methods, the step of adjusting the time ratio of high and low energy exposures at the specific angle based on the signal intensity required by the patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensities, to obtain the high and low energy exposure time at the specific angle, includes:

[0032] The formula for calculating the intensity balance between high and low energy is:

[0033] T H *ρ H =T L *ρ L .

[0034] In some feasible methods, the step of adjusting the high- and low-energy exposure times according to the signal intensity required by the patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensities, to obtain the high and low energy exposure times at the specific angle, includes:

[0035] Based on the weighted sum of the high-energy spectrum energies and the weighted sum of the low-energy spectrum energies, the high-energy integration time and the low-energy integration time are determined, where...

[0036] The formula for calculating the high-energy integration time is as follows:

[0037]

[0038] The formula for calculating the low-energy integration time is as follows:

[0039]

[0040] In some feasible methods, the step of adjusting the high- and low-energy exposure times according to the signal intensity required by the patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensities, to obtain the high and low energy exposure times at the specific angle, includes:

[0041] When the integration time allocation is dynamically adjusted, the integration time group allocation at a specific angle θ is as follows:

[0042] I(θ)=T h (θ)*ρ H +T l (θ)*ρ L ;

[0043] If the low-energy integration time at a specific angle θ is dynamically proportionally adjusted, then the integration time group allocation at that specific angle θ is as follows:

[0044] T l (θ)=α(θ)*T L ;

[0045] I(θ)=(T-α(θ)*T L )*ρ H +α(θ)*T L *ρ L ;

[0046] Where α represents the dynamic scaling factor.

[0047] In some feasible methods, the step of adjusting the high- and low-energy exposure times according to the signal intensity required by the patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensities, to obtain the high and low energy exposure times at the specific angle, includes:

[0048] High and low energy exposure time T at a specific angle θ l (θ) and T h (θ) are respectively:

[0049]

[0050] Where, the range of values ​​for α(θ) is...

[0051] T l (θ)=α(θ)*TL ,T h (θ)=T-α(θ)*T L .

[0052] Secondly, this application provides a dose modulation system under rapid kilovolt switching, applied to the aforementioned dose modulation method under rapid kilovolt switching, the system comprising:

[0053] The division unit is used to divide the circumferential data acquisition angle of CT energy spectrum imaging scan into multiple high and low energy integration time groups to obtain integration time groups under multiple angles.

[0054] The processing unit is used to determine the signal intensity required for the average body size of the patient based on the high and low energy integration time group at a specific angle, wherein the specific angle represents any angle among multiple angles;

[0055] The processing unit is also used to adjust the signal strength according to the difference between the signal strength required for the average body size of the patient and the body size distribution of the current patient, so as to obtain the signal strength required for the current patient at the specific angle;

[0056] The result unit is used to adjust the time ratio of high and low energies according to the signal intensity required by the current patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensity, to obtain the high and low energy exposure time at the specific angle, wherein the high and low energies represent the total weighted energy of the high energy spectrum and the total weighted energy of the low energy spectrum, which are known.

[0057] The weighted energy sum ρ of the high energy spectrum H Represented as:

[0058] ρ H =∑(S H (E)*E);

[0059] The weighted energy sum ρ of the low energy spectrum L Represented as:

[0060] ρ L =∑(S L (E)*E);

[0061] Among them, S H , representing the high-energy X-ray spectral distribution function, S L , represents the low-energy X-ray energy spectrum distribution function, and E, represents the X-ray photon energy.

[0062] Thirdly, this application provides a computer program that, when executed by a processor, implements the steps of the aforementioned method.

[0063] Beneficial Effects: This application provides a dose modulation method under rapid kilovolt switching. The circumferential data acquisition angle of CT energy spectrum imaging scan is divided into multiple high- and low-energy integration time groups, resulting in multiple integration time groups at various angles. Based on the high- and low-energy integration time groups at specific angles, the signal intensity required for the average patient body size is determined, where the specific angle represents any angle among the multiple angles. Based on the signal intensity required for the average patient body size and the difference in body size distribution between the current patient and the current patient, the signal intensity is adjusted to obtain the signal intensity required for the current patient at the specific angle. With a fixed total integration time and balanced high- and low-energy intensities, the high- and low-energy time ratio is adjusted based on the signal intensity required for the current patient at the specific angle, resulting in the high- and low-energy exposure time at the specific angle. Through this method, the current remains constant, and the dose difference requirements and corresponding difference control for different body sizes are achieved by adjusting the high- and low-energy time ratios at specific angles. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This is a flowchart of a dose modulation method under rapid kilovolt switching in one embodiment. Detailed Implementation

[0066] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all couplings of one or more of the associated listed items.

[0068] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0069] The following explanations of some terms used in this application are provided to aid in understanding the application:

[0070] Dual-energy spectroscopy (DSG) imaging is a computed tomography technique based on two different X-ray energy levels. By analyzing the differences in the attenuation of matter at different energies, it generates multi-parameter images to provide richer diagnostic information. It employs two different tube voltages (e.g., 80kVp and 140kVp) of X-rays, or uses a dual-layer detector to distinguish between high- and low-energy photons, while simultaneously acquiring data.

[0071] Beer-Lambert's law (also known as Beer's Law or Lambert-Beer Law) is a fundamental physical law describing the attenuation of light (or electromagnetic radiation) as it propagates through an absorbing medium. It is widely used in fields such as spectroscopy, chemical analysis, and medical imaging (e.g., CT scans).

[0072] like Figure 1 As shown, in a first aspect, this application provides a dose modulation method under rapid kilovolt switching, the method comprising:

[0073] S100 divides the circumferential data acquisition angle of CT energy spectrum imaging scan into multiple high and low energy integration time groups, thus obtaining integration time groups under multiple angles.

[0074] Specifically, obtaining the integration time set from multiple angles may include the following steps:

[0075] The circumferential data acquisition angle of CT energy spectral imaging scan is divided into n equally divided high and low energy integration time groups T, resulting in n integration time groups at each angle. The calculation formula for the integration time group at each angle is as follows:

[0076]

[0077] Where T represents the total integration time of the high-energy and low-energy times corresponding to each angular interval, and n represents the number of equal divisions of the circumference.

[0078] It should be noted that the value of n satisfies the actual hardware switching speed limit (such as microsecond-level switching) and angular resolution requirements (such as n≥360 corresponding to 1° resolution).

[0079] Divide the circumferential angle into equal parts, and divide the 2π radian (360°) circular scanning range into n equal parts, each part corresponding to the angle interval θ. i (i = 1, 2, ..., n).

[0080] The sum of high-energy and low-energy exposure times within each angular interval (T) is inversely proportional to the number of circumferential divisions (n). Specifically, for dose control: the larger T is, the higher the dose per angular angle, but the lower the noise.

[0081] For example, during angle switching, the high-voltage generator is controlled at T h (θ) and T l Within the time interval (θ), high-energy (e.g., 140kV) and low-energy (e.g., 80kV) X-rays are output respectively. Each angular interval θ i Within the time window T, the detector completes integration and resets the signal.

[0082] S200 determines the signal intensity required for the average body size of a patient based on the high and low energy integration time groups at a specific angle.

[0083] Wherein, the specific angle refers to any angle among multiple angles.

[0084] Specifically, determining the signal strength required to determine the average body size of patients may include the following steps:

[0085] The formula for calculating the integral time set at each specific angle θ is:

[0086] T = T h (θ)+T l (θ);

[0087] Among them, T h , representing the dynamically adjusted high-energy integration time, T l , represents the low-energy integration time after dynamic adjustment, and θ represents the circumferential acquisition angle.

[0088] Furthermore, the physical meaning of the formula:

[0089] T represents the total integration time at a single angle (a fixed value, calculated from step S100).

[0090] T h , which represents the high-energy integration time (exposure time in high-kilovolt mode).

[0091] T l , which represents the low-energy integration time (exposure time in low-kilovolt mode).

[0092] θ represents the current scanning angle, used to locate the patient's body shape parameter d(θ).

[0093] The formula for calculating the signal strength required for the average patient body size is:

[0094] I base =T H *ρ H +T L *ρ L ;

[0095] Among them, I base ρ represents the signal strength (reference signal strength) required for the average patient size.H ρ represents the weighted sum of energies in the high-energy spectrum. L T represents the weighted sum of the low-energy spectrum energies. H , representing the baseline high-energy integration time, T L , representing the baseline low-energy integration time.

[0096] It should be noted that, based on the integral time set at a specific angle, the baseline signal intensity required to calculate the average patient body size is used to provide a reference for subsequent dynamic dose modulation. Among these, the average body size... This was derived from a large amount of clinical data, such as the median value of the equivalent diameter of patients.

[0097] S300, based on the signal strength required for the average body size of the patient and the difference in body size distribution of the current patient, the signal strength is adjusted to obtain the signal strength required for the current patient at the specific angle.

[0098] Specifically, obtaining the signal strength required by the current patient at the specific angle may include the following steps:

[0099] The formula for calculating the signal strength required by the current patient at the specified angle is as follows:

[0100]

[0101] I base =T H *ρ H +T L *ρ L =(TT) L )*ρ H +T L *ρ L ;

[0102] Where I(θ) represents the target signal intensity at the current angle θ, u represents the adjustment coefficient (the sensitivity of the control signal to differences in body shape distribution), and d(θ) represents the patient's body shape parameters at the current angle θ. This represents the average body size parameter.

[0103] It should be noted that for each specific angle θ, the integration time set, T = T h (θ)+T l (θ), where T h (θ),T l (θ) represents the integration time corresponding to high and low kilovolt energy at a specific angle θ, when the average body size is The required strength is I base Then, the required strength I(θ) is given by the body shape d(θ) at angle θ.

[0104] It should also be noted that d(θ) can be extracted from CT localization images (Scout View) or real-time detector data, representing the patient's body thickness at that angle.

[0105] u represents the adjustment coefficient, which controls the sensitivity of signal intensity to differences in body size distribution. It can be obtained by fitting experimental or clinical data, such as u = 0.05cm. -1 This means that for every 1cm increase in thickness, the signal strength increases by 5%.

[0106] The difference in body size distribution has an exponential relationship with X-ray attenuation (which conforms to Beer-Lambert's law), so the signal needs to be adjusted exponentially to compensate for the attenuation difference.

[0107] S400, with a fixed total integration time and balanced high and low energy intensities, adjusts the high and low energy time ratio according to the signal intensity required by the current patient at the specific angle, to obtain the high and low energy exposure time at the specific angle.

[0108] Specifically, obtaining the high and low energy exposure times at the specific angle may include the following steps:

[0109] The formula for calculating the intensity balance between high and low energy is:

[0110] T H *ρ H =T L *ρ L .

[0111] In other words, to ensure a balance between high and low energy intensities, both sides of the formula need to be equal. Verifying the equilibrium condition under baseline conditions ensures the quality of the energy spectrum data. Ensuring a balance between the contributions of high and low energy signals to the decomposition of matter avoids bias in the energy spectrum data.

[0112] Given the weighted sum of high-energy spectral energies and the weighted sum of low-energy spectral energies:

[0113] Where, ρ H ρ L Given that:

[0114] The weighted sum of the high-energy spectrum is expressed as:

[0115] ρ H =∑(S H (E)*E);

[0116] The weighted sum of the low-energy spectrum is expressed as:

[0117] ρ L =∑(S L (E)*E);

[0118] Among them, SH , representing the high-energy X-ray spectral distribution function, S L , represents the low-energy X-ray energy spectrum distribution function, and E, represents the X-ray photon energy.

[0119] For example, S H (E), the energy spectrum distribution of high kilovolt (e.g., 140 kV) X-rays, showing the change in photon number with energy E. L (E) Energy spectrum distribution of low kilovolt (e.g., 80 kV) X-rays, with the number of photons varying with energy E.

[0120] Through ρ H and ρ L The ratio of high and low energy data is adjusted to improve the accuracy of matter decomposition. This ensures a reasonable allocation of high and low energy signals for different body sizes in rapid kilovolt switching CT, balancing dose optimization and imaging quality.

[0121] Based on the weighted sum of the high-energy spectrum energies and the weighted sum of the low-energy spectrum energies, the high-energy integration time and the low-energy integration time are determined, where...

[0122] The formula for calculating the high-energy integration time is as follows:

[0123]

[0124] The formula for calculating the low-energy integration time is as follows:

[0125]

[0126] The integral time series T = T at a specific angle θ under dynamic adjustment conditions h (θ)+T l (θ) can be assigned as:

[0127] I(θ)=T h (θ)*ρ H +T l (θ)*ρ L ;

[0128] If the low-energy integration time at a specific angle θ is dynamically proportionally adjusted, then the integration time group allocation at that specific angle θ is as follows:

[0129] Let T l (θ)=α(θ)*T L ,but:

[0130] I(θ)=(T-α(θ)*T L )*ρ H +α(θ)*T L *ρ L ;

[0131] Where α represents the dynamic scaling factor.

[0132] Introducing a dynamic scaling factor α, for T l (θ) and T h (θ) is used for allocation and adjustment. This facilitates calculations in subsequent steps. The adjustment step size of α needs to match the minimum switching time of the high-voltage generator (e.g., microseconds).

[0133] High and low energy exposure time T at a specific angle θ l (θ) and T h (θ) are respectively:

[0134]

[0135] Combining the aforementioned equations, we obtain:

[0136]

[0137] Where, the range of values ​​for α(θ) is...

[0138] The high and low energy exposure time T at a specific angle θ is obtained from the previous formula. l (θ) and T h (θ):

[0139] T l (θ)=α(θ)*T L ,T h (θ)=T-α(θ)*T L .

[0140] In other words, the high and low energy exposure times at angle θ are T and T, respectively. l (θ)=α(θ)*T L ,T h (θ)=T-α(θ)*T L .

[0141] In summary, the dose modulation method under rapid kilovolt switching provided in this application has the following beneficial effects:

[0142] 1. Precise dose modulation reduces radiation risk.

[0143] Dynamic adaptability: Based on the real-time differences in body shape distribution (d(θ)) of patients under different scanning angles, an exponential model is used. Dynamically adjust signal strength and optimize the high and low energy integration time allocation (t) h (θ), T l (θ)), avoid overexposure.

[0144] Body size sensitivity control: The adjustment coefficient u can be flexibly configured to balance dose and image quality, significantly reducing radiation for children or small patients (dose reduction of 20-30% in typical scenarios).

[0145] 2. Balanced energy spectrum data improves imaging quality.

[0146] High and low energy signal equalization constraint: through equalization condition T H ρ H =T L ρ L This ensures that high- and low-energy data contribute consistently to the decomposition of substances, reduces energy spectrum artifacts, and improves the quantitative analysis accuracy of dual-energy CT (e.g., uric acid crystal detection error <5%).

[0147] Energy Spectrum Parameter Calibration: Based on Pre-Experimental Measurement of Energy Spectrum Distribution (ρ) H =∑S H (E)·E,ρ L =∑S L (E)·E), ensuring the calculation of the reference signal strength I base The accuracy.

[0148] 3. Strong hardware compatibility, simplifying implementation complexity.

[0149] Fixed tube current design: eliminates the need for dynamic modulation of tube current, avoids the technical bottleneck of transient current response under rapid kilovolt switching, and reduces the difficulty of high voltage generator control.

[0150] Real-time control optimization: Dynamically allocate time (T) using the proportional coefficient α(θ). l (θ)=α(θ)T L It requires only microsecond-level FPGA computation and is adapted to high-speed rack rotation (e.g., 0.28 seconds / revolution).

[0151] 4. Highly efficient in calculation and widely applicable in clinical practice.

[0152] Predefined mathematical framework: baseline parameter (T) H T L The dynamic formula (α(θ)) is calculated quickly through closed-form solutions, reducing the real-time computational load and ensuring compatibility with existing CT image reconstruction workflows.

[0153] Multi-scenario adaptability: Supports expansion from conventional scanning to energy dispersive imaging, and can be adapted to different resolution and dose requirements by adjusting parameters n (number of circumferential divisions) and T (integration time).

[0154] Secondly, this application provides a dose modulation system under rapid kilovolt switching, applied to the aforementioned dose modulation method under rapid kilovolt switching, the system comprising:

[0155] The division unit is used to divide the circumferential data acquisition angle of CT energy spectrum imaging scan into multiple high and low energy integration time groups to obtain integration time groups under multiple angles.

[0156] The processing unit is used to determine the signal intensity required for the average body size of the patient based on the high and low energy integration time group at a specific angle, wherein the specific angle represents any angle among multiple angles;

[0157] The processing unit is also used to adjust the signal strength according to the difference between the signal strength required for the average body size of the patient and the body size distribution of the current patient, so as to obtain the signal strength required for the current patient at the specific angle;

[0158] The result unit is used to adjust the time ratio of high and low energies according to the signal intensity required by the current patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensity, to obtain the high and low energy exposure time at the specific angle, wherein the high and low energies represent the total weighted energy of the high energy spectrum and the total weighted energy of the low energy spectrum, which are known.

[0159] The weighted energy sum ρ of the high energy spectrum H Represented as:

[0160] ρ H =∑(S H (E)*E);

[0161] The weighted energy sum ρ of the low energy spectrum L Represented as:

[0162] ρ L =∑(S L (E)*E);

[0163] Among them, S H , representing the high-energy X-ray spectral distribution function, S L , represents the low-energy X-ray energy spectrum distribution function, and E, represents the X-ray photon energy.

[0164] Thirdly, this application provides a computer program that, when executed by a processor, implements the steps of the aforementioned method.

[0165] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0166] The various embodiments in this disclosure are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0167] The scope of protection of this disclosure is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its scope and spirit. If such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, then the intent of this disclosure also includes such modifications and variations.

Claims

1. A method of dose modulation for fast kilovoltage switching, characterized in that, The methods include: The circumferential data acquisition angle of CT energy spectrum imaging scan is divided into multiple high and low energy integration time groups to obtain multiple integration time groups under multiple angles. Based on the high and low energy integration time group at a specific angle, the signal intensity required to determine the average body size of the patient is determined, wherein the specific angle refers to any angle among multiple angles; Based on the signal strength required for the average body size of the patient and the difference in body size distribution of the current patient, the signal strength is adjusted to obtain the signal strength required for the current patient at the specific angle; With a fixed total integration time and balanced high and low energy intensities, the time ratio of high and low energies is adjusted according to the signal intensity required by the patient at the specific angle to obtain the high and low energy exposure times at the specific angle. Here, "high" and "low" energies refer to the sum of the weighted high-energy spectrum and the sum of the weighted low-energy spectrum, given that both are known. The weighted sum of the high energy spectrum Represented as: ； The weighted energy sum of the low energy spectrum Represented as: ； in, , representing the energy spectrum distribution function of high-energy X-rays. , representing the energy spectrum distribution function of low-energy X-rays. , representing the energy of an X-ray photon; The step of dividing the circumferential data acquisition angle of CT energy spectral imaging scan into multiple high- and low-energy integration time groups to obtain multiple integration time groups at multiple angles includes: The circumferential data acquisition angle of CT energy dispersive imaging scan is divided into equal parts. A high- and low-energy integration time set T is obtained. The integral time set under each angle is given by the following formula: ； Where T represents the total integration time for the high-energy and low-energy periods corresponding to each angular interval. , indicating the number of equal parts into which the circumference is divided; The step of determining the signal intensity required for the average body size of a patient based on the high and low energy integration time group at a specific angle includes: Each specific angle The formula for calculating the integral time group is as follows: ； in, This indicates the high-energy integration time after dynamic adjustment. This represents the low-energy integration time after dynamic adjustment. , indicating the circumferential acquisition angle; The formula for calculating the signal strength required for the average patient body size is: ； in, This represents the signal strength required for the average body size of patients. , representing the baseline high-energy integration time. , representing the baseline low-energy integration time.

2. The dose modulation method under rapid kilovolt switching according to claim 1, characterized in that, The step of adjusting the signal strength based on the difference between the average body size of the patient and the current body size distribution to obtain the signal strength required by the current patient at the specific angle includes: The formula for calculating the signal strength required by the current patient at the specified angle is as follows: ； ； in, , indicating the current angle Below, the signal strength required by the current patient. , represents the adjustment factor. , indicating the current angle The patient's body shape parameters are as follows: , representing the average body size parameter.

3. The dose modulation method under rapid kilovolt switching according to claim 2, characterized in that, The step of adjusting the high and low energy exposure time ratio based on the signal intensity required by the patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensity, to obtain the high and low energy exposure time at the specific angle, includes: The formula for calculating the intensity balance between high and low energy is: 。 4. The dose modulation method under rapid kilovolt switching according to claim 3, characterized in that, The step of adjusting the high- and low-energy exposure times at a specific angle, based on the signal intensity required by the patient at the specific angle and with a fixed total integration time and balanced high and low energy intensities, includes: Based on the weighted sum of high-energy spectra and the weighted sum of low-energy spectra, the high-energy integration time and the low-energy integration time are determined, wherein... The formula for calculating the high-energy integration time is as follows: ； The formula for calculating the low-energy integration time is as follows: 。 5. The dose modulation method under rapid kilovolt switching according to claim 4, characterized in that, The step of adjusting the high- and low-energy exposure times at a specific angle, based on the signal intensity required by the patient at the specific angle and with a fixed total integration time and balanced high and low energy intensities, includes: Under the condition of dynamically adjusting the integration time allocation, at a specific angle The following integration time groups are allocated as follows: ； If a specific angle By dynamically adjusting the low-energy integration time, a specific angle can be achieved. The following integration time groups are allocated as follows: ； ； in, , representing the dynamic scaling factor.

6. The dose modulation method under rapid kilovolt switching according to claim 5, characterized in that, The step of adjusting the high- and low-energy exposure times at a specific angle, based on the signal intensity required by the patient at the specific angle and with a fixed total integration time and balanced high and low energy intensities, includes: Specific angle High and low energy exposure time and They are respectively: ； ； in, The range of values ​​is ; , 。 7. A dose modulation system under rapid kilovolt switching, characterized in that, The dose modulation method applied under rapid kilovolt switching as described in any one of claims 1 to 6, the system comprising: The division unit is used to divide the circumferential data acquisition angle of CT energy spectrum imaging scan into multiple high and low energy integration time groups to obtain integration time groups under multiple angles. The processing unit is used to determine the signal intensity required for the average body size of the patient based on the high and low energy integration time group at a specific angle, wherein the specific angle represents any angle among multiple angles; The processing unit is also used to adjust the signal strength according to the difference between the signal strength required for the average body size of the patient and the body size distribution of the current patient, so as to obtain the signal strength required for the current patient at the specific angle; The result unit is used to adjust the time ratio of high and low energies according to the signal intensity required by the current patient at the specific angle, under the condition of fixed total integration time and balanced high and low energy intensity, to obtain the high and low energy exposure time at the specific angle, wherein the high and low energies represent the total weighted energy of the high energy spectrum and the total weighted energy of the low energy spectrum, which are known. The weighted sum of the high energy spectrum Represented as: ； The weighted energy sum of the low energy spectrum Represented as: ； in, , representing the energy spectrum distribution function of high-energy X-rays. , representing the energy spectrum distribution function of low-energy X-rays. , representing the energy of an X-ray photon.

8. A computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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