A Dose Rate Control Method and Device for Intensity Modulated Arc Therapy

Abstract

The present invention discloses a dose rate control method and device for intensity-modulated arc therapy. The dose rate control method includes: formulating a beam treatment plan according to the dose rate control modes of continuous motion intervals and transition intervals to obtain the monitor units of each sub-field; calculating the relative dose rate of two adjacent continuous motion intervals; determining the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub-field. When the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, the relative dose rate of the transition interval between two adjacent continuous motion intervals is set to be between the relative dose rates of the two continuous motion intervals. The present invention proposes a setting mode for the transition motion interval between continuous motion intervals and a relative dose rate optimization algorithm model to accurately implement the motion model of the linear accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy, and particularly to a method and device for controlling the dose rate in rotational intensity modulated radiotherapy. Background Art

[0002] Volumetric modulated arc therapy (VMAT) is an advanced IMRT technology. By adjusting the multi-leaf collimator in the accelerator and the gantry rotation speed at each angle, not only can the radiation intensity be weakened or enhanced according to the thickness of the tumor, but also the most suitable radiation intensity can be given considering the different thicknesses of different parts of the tumor volume. Its superiority lies in 360-degree rotational irradiation, with a larger range, greater flexibility, and higher precision. Different from the intensity modulation technology with fixed radiation fields, during VMAT, while the gantry rotates around the patient isocentrically, the collimator continuously changes the radiation field size and open field shape according to the current dose rate. VMAT integrates the rotation of the gantry, the change of the dose rate, and the movement of the collimator, greatly improving the treatment efficiency. During the treatment process, the gantry rotates around the patient, and the positions of the multi-leaf collimator blades change with the angle to form an optimized shape. During beam output, the accelerator is controlled to perform arc treatment, and at the same time, the multi-leaf collimator is controlled to dynamically and gradually complete a series of radiation field shapes.

[0003] When formulating an intensity modulated radiotherapy plan for existing rotational intensity modulated radiotherapy, it mainly depends on the treatment requirements of the irradiated treatment organ, so as to determine the dose rate corresponding to each continuous movement interval of rotational intensity modulation. Since this planning process only considers the treatment requirements of the irradiated organ, the dose rates of two adjacent continuous movement intervals may differ greatly, which puts higher requirements on the dose rate switching control of the linear accelerator. As a result, it is difficult to execute due to overly high requirements for the linear accelerator, and it is easy to lead to poor QA results.

[0004] Therefore, in order to solve the problem of free control of the rotation speed and dose rate in rotational intensity modulation, the prior art has the technical problems of being difficult to execute due to overly high requirements for the accelerator and being unable to control the dose rate of rotational intensity modulation. The present invention patent is specifically proposed. Summary of the Invention

[0005] In order to solve the problem of free control of the rotation speed and dose rate in rotational intensity modulation, in combination with the rotational intensity modulation optimization model, the present invention provides a method and device for controlling the dose rate in rotational intensity modulated radiotherapy, enabling the accelerator in rotational intensity modulation to accelerate or decelerate evenly, and the dose optimization to be freely optimized within the control range, avoiding the overly high requirements for the accelerator in the traditional method and being difficult to execute, thereby solving the problem of controlling the dose rate of rotational intensity modulation. Specifically, the following technical solutions are adopted:

[0006] A method for controlling the dose rate in rotational intensity modulated radiotherapy includes:

[0007] Determine the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub - field. Generally, according to the industry - used criteria, the continuous motion interval is usually set to 16°, and the transition interval is 4°;

[0008] Calculate the relative dose rates of two adjacent continuous motion intervals;

[0009] According to the dose rate control modes of the continuous motion intervals and the transition intervals, formulate the beam treatment plan for radiotherapy, and obtain the monitor units of each sub - field. When the difference or ratio between the relative dose rate of the next continuous motion interval and that of the previous continuous motion interval is greater than or less than a preset threshold, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose rates of the two continuous motion intervals.

[0010] As an optional implementation manner of the present invention, in a dose rate control method for rotational intensity - modulated radiotherapy of the present invention, the formulating the beam treatment plan for radiotherapy and obtaining the monitor units of each sub - field includes:

[0011] Preset an optimization algorithm model:

[0012] min{F}=(D t - D p ) 2

[0013] D t = M×∑MU×I ij

[0014] Wherein, D t represents the actual irradiation dose, D p represents the prescribed dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub - field;

[0015] Input the known variables D p , M, I ij into the optimization algorithm model, and solve for the approximate optimal monitor units MU s1 , MU s2 , …, MU sn .

[0016] As an optional implementation manner of the present invention, in a dose rate control method for rotational intensity - modulated radiotherapy of the present invention, the determining the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub - field includes:

[0017] The continuous motion interval contains multiple sub - fields, and the monitor unit MU of the continuous motion intervalQ It is equal to the sum of the monitor units of each sub - field within the interval, and controls the linear accelerator to maintain a continuous acceleration or continuous deceleration state within the continuous motion interval;

[0018] The sum of the rotation angles of all the continuous motion intervals and the rotation angles of all the transition intervals is equal to the rotation angle of the intensity - modulated radiation therapy.

[0019] As an optional implementation manner of the present invention, in a dose - rate control method for intensity - modulated radiation therapy, the calculation of the relative dose - rate between two adjacent continuous motion intervals includes:

[0020] According to the formula: where, MU Q is the monitor unit of the continuous motion interval, degree represents the rotation angle of the continuous motion interval, and redoserate represents the relative dose - rate;

[0021] Calculate the relative dose - rates redoserate1, redoserate2,..., redoserate of each continuous motion interval m .

[0022] As an optional implementation manner of the present invention, in a dose - rate control method for intensity - modulated radiation therapy, when the difference or ratio between the relative dose - rate of the next continuous motion interval and the relative dose - rate of the previous continuous motion interval is greater than or less than a preset threshold, setting the relative dose - rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose - rates of the two continuous motion intervals includes:

[0023] Judge whether the relative dose - rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose - rate redoserate of the previous continuous motion interval (m-1) satisfy: or where, η1, η2 are preset values, and the value range is η1 > 9,

[0024] If the judgment result is yes, set the relative dose - rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1)) / 2. If the judgment result is negative, the relative dose rate of the transition interval between two adjacent consecutive motion intervals is set to the relative dose rate redoserate of the previous consecutive motion interval among the two adjacent consecutive motion intervals. (m-1) , where the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

[0025] As an optional implementation manner of the present invention, in a dose rate control method for rotational intensity modulated radiotherapy of the present invention, when the difference or ratio between the relative dose rate of the next consecutive motion interval and the relative dose rate of the previous consecutive motion interval is greater than or less than a preset threshold, setting the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between the relative dose rates of the two consecutive motion intervals includes:

[0026] Judging the relative dose rate redoserate of the next consecutive motion interval among two adjacent consecutive motion intervals m and the relative dose rate redoserate of the previous consecutive motion interval (m-1) Whether it satisfies: |redoserate m -redoserate (m-1) |>redoserate0, where redoserate0 is a preset relative dose rate difference threshold, and the value range is redoserate0>9;

[0027] If the judgment result is positive, the relative dose rate of the transition interval between two adjacent consecutive motion intervals is set to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is negative, the relative dose rate of the transition interval between two adjacent consecutive motion intervals is set to the relative dose rate redoserate of the previous consecutive motion interval among the two adjacent consecutive motion intervals. (m-1) , where the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

[0028] As an optional implementation manner of the present invention, a dose rate control method for rotational intensity modulated radiotherapy of the present invention includes:

[0029] During the rotational intensity modulated radiotherapy process, controlling the linear accelerator to maintain a continuously accelerating or continuously decelerating state within the consecutive motion intervals, and maintaining the same relative dose rate within the same consecutive motion interval;

[0030] If the relative dose rate of the transition interval is set to be between the relative dose rates of two consecutive motion intervals, the control unit controls the linear accelerator to switch the acceleration to enter the transition interval and maintains the same relative dose rate within the same transition interval.

[0031] The present invention also provides a dose rate control device for rotational intensity modulated radiotherapy, comprising:

[0032] A treatment plan module, which formulates a field treatment plan for radiotherapy according to the dose rate control modes of the continuous motion intervals and the transition intervals, obtains the monitor units of each sub-field, and determines the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub-field;

[0033] A relative dose rate calculation module, which calculates the relative dose rates of two adjacent continuous motion intervals;

[0034] A control module, which determines that when the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, the relative dose rate of the transition interval between two adjacent continuous motion intervals is set to be between the relative dose rates of the two continuous motion intervals.

[0035] As an optional implementation manner of the present invention, the treatment plan module includes:

[0036] An optimization algorithm model module, which presets an optimization algorithm model:

[0037] min{F}=(D t -D p ) 2

[0038] D t =M×∑MU×I ij

[0039] Wherein, D t represents the actual irradiation dose, D p represents the prescribed dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub-field;

[0040] Input the known variables D p , M, and I ij into the optimization algorithm model, and solve the approximate optimal monitor units MU s1 , MU s2 , …, MU sn of each sub-field when the objective function value F tends to the minimum value;

[0041] The motion interval planning module determines the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub - field:

[0042] The continuous motion intervals include multiple sub - fields, and the monitor units (MU) of the continuous motion intervals Q are equal to the sum of the monitor units of each sub - field within the interval, and control the linear accelerator to maintain a continuously accelerating or continuously decelerating state within the continuous motion interval;

[0043] The sum of the rotation angles of all the continuous motion intervals and the sum of the rotation angles of all the transition intervals are equal to the rotation angle of the intensity - modulated radiation therapy with rotation.

[0044] As an alternative implementation manner of the present invention, the relative dose rate calculation module calculates the relative dose rates of two adjacent continuous motion intervals as follows:

[0045] According to the formula: where MU Q is the monitor unit of the continuous motion interval, degree represents the rotation angle of the continuous motion interval, and redoserate represents the relative dose rate;

[0046] Calculate the relative dose rates redoserate1, redoserate2,..., redoserate of each continuous motion interval m ;

[0047] Judge whether the relative dose rate redoserate m of the next continuous motion interval in two adjacent continuous motion intervals (m-1) meets: or where η1, η2 are preset values, and the value range is η1 > 9,

[0048] If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be the relative dose rate redoserate (m-1) of the previous continuous motion interval in two adjacent continuous motion intervals, where the order of the continuous interval numbers itself is determined according to the clockwise rotation order.

[0049] Alternatively, determine the relative dose rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose rate redoserate of the previous continuous motion interval (m-1) to see if it satisfies: |redoserate m - redoserate (m-1) | > redoserate0, where redoserate0 is a preset relative dose rate difference threshold, and the value range is redoserate0 > 9;

[0050] If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , with the value being (redoserate m + redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be the relative dose rate redoserate of the previous continuous motion interval in the two adjacent continuous motion intervals (m-1) , where the order of the numbers of the continuous intervals themselves is determined according to the clockwise rotation order.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] A dose rate control method for rotational intensity modulated radiotherapy of the present invention, by setting the relative dose rate of the transition motion interval between two adjacent continuous motion intervals with a large difference in relative dose rates to be between the relative dose rates of the two continuous motion intervals: the continuous motion interval is the same relative dose rate within a section of interval, and is a stable acceleration or deceleration process of the accelerator; when the relative dose rates of the previous continuous motion interval and the next continuous motion interval are different and the difference is large, set the relative dose rate of the transition interval to be between the relative dose rate of the previous continuous motion interval and the relative dose rate of the next continuous motion interval. Through the transition of the transition interval, it is avoided that the linear collimator is not easy to switch control due to a large difference in relative dose rates when switching speeds between two adjacent continuous motion intervals.

[0053] Therefore, a dose rate control method for rotational intensity modulated radiotherapy of the present invention is more likely to realize the switching control of the linear accelerator between two adjacent continuous motion intervals, and can make the linear accelerator in rotational intensity modulation accelerate and decelerate uniformly, and the dose optimization can be freely optimized within the control range, avoiding the excessive requirements for the accelerator in the traditional method and being difficult to execute, thus solving the problem of dose rate control in rotational intensity modulation. Description of the Drawings

[0054] Figure 1 Flow chart of a dose rate control method for intensity modulated arc radiotherapy according to an embodiment of the present invention;

[0055] Figure 2 Example diagram of adding a transition motion interval between two adjacent consecutive motion intervals in a dose rate control method for intensity modulated arc radiotherapy according to an embodiment of the present invention. Detailed implementation manners

[0056] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present invention.

[0057] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0059] It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0060] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the inventive product is normally placed, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0061] See Figure 1 As shown, a dose rate control method for intensity modulated arc radiotherapy in this embodiment includes:

[0062] Determining consecutive motion intervals of a linear accelerator and transition intervals between two adjacent consecutive motion intervals based on the monitor units of each sub - field;

[0063] Calculate the relative dose rate between two adjacent consecutive motion intervals;

[0064] According to the dose rate control modes of the consecutive motion intervals and the transition intervals, formulate a field treatment plan for radiotherapy to obtain the monitor units of each sub-field. When the difference or ratio between the relative dose rate of the next consecutive motion interval and the relative dose rate of the previous consecutive motion interval is greater than or less than a preset threshold, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between the relative dose rates of the two consecutive motion intervals.

[0065] A dose rate control method for intensity-modulated arc radiotherapy in this embodiment, by setting the relative dose rate of the transition motion interval between two adjacent consecutive motion intervals with a large difference in relative dose rate to be between the relative dose rates of the two consecutive motion intervals: The consecutive motion interval is the same relative dose rate within a section of the interval, and it is a stable acceleration or deceleration process of the accelerator; when the relative dose rate of the previous consecutive motion interval is different from that of the next consecutive motion interval and the difference is large, set the relative dose rate of the transition interval to be between the relative dose rate of the previous consecutive motion interval and the relative dose rate of the next consecutive motion interval. A dose rate control method for intensity-modulated arc radiotherapy in this embodiment, through the transition of the transition interval, avoids the difficulty of switching control due to a large difference in relative dose rate when the linear collimator switches speeds between two adjacent consecutive motion intervals.

[0066] Therefore, a dose rate control method for intensity-modulated arc radiotherapy in this embodiment is more likely to achieve the switching control of the linear accelerator between two adjacent consecutive motion intervals, which can enable the linear accelerator in intensity-modulated arc radiotherapy to accelerate and decelerate uniformly, and the dose optimization can be freely optimized within the control range, avoiding the excessive requirements for the accelerator in the traditional method and being difficult to execute, thus solving the problem of dose rate control in intensity-modulated arc radiotherapy.

[0067] As Figure 2 shown, for the transition interval B between two consecutive motion intervals A and C, control the linear accelerator to maintain the same relative dose rate within the consecutive motion intervals A, C, and the transition interval B respectively. The relative dose rate of the transition interval B is between the relative dose rate of the consecutive motion interval A and the relative dose of the consecutive motion interval C, and switch the speed of the linear accelerator from the consecutive motion interval A to the consecutive motion interval C through the transition of the transition interval B.

[0068] As an optional implementation manner of this embodiment, in a dose rate control method for intensity-modulated arc radiotherapy in this embodiment, the formulating a field treatment plan for radiotherapy to obtain the monitor units of each sub-field includes:

[0069] Preset an optimization algorithm model:

[0070] min{F} = (D t - D p ) 2

[0071] D t = M × ∑MU × I ij

[0072] where D t represents the actual irradiation dose, D p represents the prescribed dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub - field;

[0073] Input the known variables D p , M, and I ij into the optimization algorithm model to solve for the approximate optimal monitor units MU s1 , MU s2 , …, MU sn of each sub - field when the objective function value F approaches the minimum value.

[0074] In this embodiment, D p is prescribed by the doctor according to the patient's condition, the dose contribution matrix M is determined by the parameters of the radiotherapy equipment itself, and I ij is optimized by the conjugate gradient method according to the prescribed doses of the planning tumor volume (PTV) and the organs at risk (OARs).

[0075] A dose rate control method for intensity - modulated arc radiotherapy in this embodiment, where determining the continuous motion intervals of the linear accelerator and the transition intervals between adjacent two continuous motion intervals based on the monitor units of each sub - field includes:

[0076] The continuous motion interval contains multiple sub - fields, and the monitor unit MU Q of the continuous motion interval is equal to the sum of the monitor units of each sub - field within the interval, and control the linear accelerator to maintain a continuously accelerating or continuously decelerating state within the continuous motion interval;

[0077] The sum of the rotation angles of all the continuous motion intervals and the rotation angles of all the transition intervals is equal to the rotation angle of the intensity - modulated arc radiotherapy.

[0078] Furthermore, a dose rate control method for intensity - modulated arc radiotherapy in this embodiment, where calculating the relative dose rates of adjacent two continuous motion intervals includes:

[0079] According to the formula: where MU QThe machine hop count for the continuous motion interval, degree represents the rotation angle of the continuous motion interval, and redoserate represents the relative dose rate;

[0080] Calculate the relative dose rates redoserate1, redoserate2,..., redoserate for each continuous motion interval m 。

[0081] As an alternative implementation of this embodiment, in a dose rate control method for rotational intensity modulated radiotherapy of this embodiment, when the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, then setting the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose rates of the two continuous motion intervals includes:

[0082] Judge whether the relative dose rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose rate redoserate of the previous continuous motion interval (m-1) satisfy: or where η1, η2 are preset values, and the value range is η1 > 9,

[0083] If the judgment result is yes, then set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, then set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be the relative dose rate redoserate of the previous continuous motion interval in the two adjacent continuous motion intervals (m-1) . Among them, the order of the continuous interval numbers itself is determined according to the clockwise rotation order.

[0084] Specific examples are as Figure 2 shown. The relative dose rate of the left continuous motion interval A is, the middle transition interval B, the right continuous motion interval C, and the relative dose rate of the continuous motion interval A is redoserate a , and the relative dose rate of the continuous motion interval C is redoserate c . If redoserate c > 9 * redoserate a, the relative dose rate redoserate of the transition interval B is b set to redoserate a <redoserate b <redoserate c . Otherwise, redoserate b = redoserate a .

[0085] As an alternative implementation of this embodiment, in a dose rate control method for rotational intensity modulated radiotherapy in this embodiment, when the difference or ratio between the relative dose rate of the next consecutive motion interval and the relative dose rate of the previous consecutive motion interval is greater than or less than a preset threshold, setting the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between the relative dose rates of the two consecutive motion intervals includes:

[0086] Judge whether the relative dose rate redoserate m of the next consecutive motion interval and the relative dose rate redoserate (m-1) of the previous consecutive motion interval in two adjacent consecutive motion intervals satisfy: |redoserate m - redoserate (m-1) | > redoserate0, where redoserate0 is a preset relative dose rate difference threshold;

[0087] If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m + redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to the relative dose rate redoserate (m-1) of the previous consecutive motion interval in two adjacent consecutive motion intervals, where the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

[0088] Furthermore, a dose rate control method for rotational intensity modulated radiotherapy in this embodiment includes:

[0089] During the rotational intensity modulated radiotherapy process, control the linear accelerator to maintain a continuous acceleration or continuous deceleration state within a consecutive motion interval, and maintain the same relative dose rate within the same consecutive motion interval;

[0090] If the relative dose rate of the transition interval is set to be between the relative dose rates of two consecutive motion intervals, control the linear accelerator to switch the acceleration to enter the transition interval and maintain the same relative dose rate within the same transition interval.

[0091] A dose rate control method for intensity modulated arc radiotherapy in this embodiment. When the relative dose rates of two adjacent consecutive motion intervals differ greatly, by setting the relative dose rate of the transition motion interval, perform transition control on the linear accelerator to avoid excessive acceleration switching of the linear accelerator when switching from the previous consecutive motion interval to the next consecutive motion interval, which is not conducive to the control of the linear accelerator. And when the relative dose rates of two adjacent consecutive motion intervals are relatively close, there is no need to introduce a transition motion interval.

[0092] This embodiment also provides a dose rate control device for intensity modulated arc radiotherapy, including:

[0093] A treatment plan module, according to the dose rate control modes of the consecutive motion intervals and the transition intervals, formulates a beam treatment plan for radiotherapy, obtains the monitor units of each sub - field, and determines the consecutive motion intervals of the linear accelerator and the transition intervals between two adjacent consecutive motion intervals based on the monitor units of each sub - field;

[0094] A relative dose rate calculation module, which calculates the relative dose rates of two adjacent consecutive motion intervals;

[0095] A control module, when determining that the difference or ratio between the relative dose rate of the next consecutive motion interval and the relative dose rate of the previous consecutive motion interval is greater than or less than a preset threshold, sets the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between the relative dose rates of the two consecutive motion intervals.

[0096] A dose rate control device for intensity modulated arc radiotherapy in this embodiment, by setting the relative dose rate of the transition motion interval between two adjacent consecutive motion intervals with a large difference in relative dose rates to be between the relative dose rates of the two consecutive motion intervals: the consecutive motion interval is the same relative dose rate within a period of time, and it is a stable acceleration or deceleration process of the accelerator; when the relative dose rates of the previous consecutive motion interval and the next consecutive motion interval are different and the gap is large, set the relative dose rate of the transition interval to be between the relative dose rate of the previous consecutive motion interval and the relative dose rate of the next consecutive motion interval. A dose rate control device for intensity modulated arc radiotherapy in this embodiment, through the transition of the transition interval, avoids the difficult switching control of the linear collimator due to the large difference in relative dose rates when switching speeds between two adjacent consecutive motion intervals.

[0097] Therefore, the dose rate control device for intensity modulated radiotherapy in this embodiment is more likely to achieve the switching control of the linear accelerator between two adjacent consecutive motion intervals, enabling the linear accelerator in intensity modulated radiotherapy to accelerate and decelerate uniformly, and allowing the dose optimization to be freely optimized within the control range. This avoids the problem that the traditional method has too high requirements for the accelerator and is not easy to execute, thus solving the problem of dose rate control in intensity modulated radiotherapy.

[0098] As an optional implementation manner of this embodiment, the treatment plan module includes:

[0099] An optimization algorithm model module with a preset optimization algorithm model:

[0100] min{F} = (D t - D p ) 2

[0101] D t = M × ∑MU × I ij

[0102] where D t represents the actual irradiation dose, D p represents the prescription dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub - field;

[0103] Input the known variables D p , M, and I ij into the optimization algorithm model, and solve for the approximate optimal monitor units MU s1 , MU s2 , …, MU sn ;

[0104] A motion interval planning module that determines the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub - field:

[0105] The continuous motion interval contains multiple sub - fields, and the monitor unit MU Q of the continuous motion interval is equal to the sum of the monitor units of each sub - field within the interval, and controls the linear accelerator to maintain a continuous acceleration or continuous deceleration state within the continuous motion interval;

[0106] The sum of the rotation angles of all the continuous motion intervals and the rotation angles of all the transition intervals is equal to the rotation angle of intensity modulated radiotherapy.

[0107] As an optional implementation manner of this embodiment, the relative dose rate calculation module calculates the relative dose rate between two adjacent continuous motion intervals including:

[0108] According to the formula: where, MU Q is the machine jump number in the continuous motion interval, degree represents the rotation angle in the continuous motion interval, and redoserate represents the relative dose rate;

[0109] Calculate the relative dose rates redoserate1, redoserate2,..., redoserate of each continuous motion interval m ;

[0110] Judge whether the relative dose rate redoserate m of the next continuous motion interval and the relative dose rate redoserate (m-1) of the previous continuous motion interval in two adjacent continuous motion intervals satisfy: or where, η1 and η2 are preset values, and the value range is η1>9,

[0111] If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be the relative dose rate redoserate (m-1) of the previous continuous motion interval in the two adjacent continuous motion intervals. Among them, the order of the continuous interval numbers itself is determined according to the clockwise rotation order.

[0112] Or, judge whether the relative dose rate redoserate m of the next continuous motion interval and the relative dose rate redoserate (m-1) of the previous continuous motion interval in two adjacent continuous motion intervals satisfy: |redoserate m -redoserate (m-1) |>redoserate0, where redoserate0 is the preset relative dose rate difference threshold;

[0113] If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m+redoserate (m-1) ) / 2. If the judgment result is negative, the relative dose rate of the transition interval between two adjacent continuous motion intervals is set to the relative dose rate redoserate of the previous continuous motion interval in the two adjacent continuous motion intervals (m-1) , where the order of the numbers of the continuous intervals themselves is determined according to the clockwise rotation order

[0114] This embodiment also provides a computer-readable storage medium storing a computer-executable program, which when executed, implements a dose rate control method for rotational intensity-modulated radiotherapy as described

[0115] The computer-readable storage medium in this embodiment may include a data signal propagated in a baseband or as part of a carrier wave, which carries the readable program code. Such a propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable storage medium may also be any readable medium other than the readable storage medium, and this computer-readable medium may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination of the above

[0116] This embodiment also provides an electronic device including a processor and a memory, the memory being used to store a computer-executable program, and when the computer program is executed by the processor, the processor executes a dose rate control method for rotational intensity-modulated radiotherapy as described

[0117] The electronic device is presented in the form of a general computing device. The processor may be one or multiple and work cooperatively. The present invention does not exclude distributed processing, that is, the processors may be dispersed in different physical devices. The electronic device of the present invention is not limited to a single entity, but may also be the sum of multiple physical devices

[0118] The memory stores a computer-executable program, usually machine-readable code. The computer-readable program may be executed by the processor so that the electronic device can execute the method of the present invention, or at least some steps of the method

[0119] The memory includes volatile memory, such as a random access storage unit (RAM) and / or a cache storage unit, and may also be non-volatile memory, such as a read-only storage unit (ROM)

[0120] It should be understood that the electronic device of the present invention may further include elements or components not shown in the above examples. For example, some electronic devices also include a display unit such as a display screen, and some electronic devices also include human-computer interaction elements such as buttons and keyboards. As long as the electronic device can execute the computer-readable program in the memory to implement at least part of the steps of the method of the present invention, it can be considered as the electronic device covered by the present invention.

[0121] From the description of the above embodiments, it is easy for those skilled in the art to understand that the present invention can be implemented by hardware capable of executing a specific computer program, such as the system of the present invention, and the electronic processing unit, server, client, mobile phone, control unit, processor, etc. included in the system. The present invention can also be implemented by computer software for executing the method of the present invention, such as control software executed by a microprocessor, an electronic control unit, a client, a server, etc. However, it should be noted that the computer software for executing the method of the present invention is not limited to being executed in one or a specific number of hardware entities, and it can also be implemented in a distributed manner by unspecified specific hardware. For computer software, the software product can be stored in a computer-readable storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), or can be distributed and stored on a network, as long as it can enable the electronic device to execute the method according to the present invention.

[0122] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above respective embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and their improvements that do not depart from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. A method for controlling the dose rate of intensity-modulated rotational radiotherapy, characterized in that Including: Formulating a field treatment plan for radiotherapy according to the dose rate control mode of the continuous motion interval and the transition interval, and obtaining the monitor units of each sub-field; Calculating the relative dose rate between two adjacent continuous motion intervals; Based on the monitor units of each sub-field, determining the continuous motion interval of the linear accelerator and the transition interval between two adjacent continuous motion intervals. When the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, the relative dose rate of the transition interval between two adjacent continuous motion intervals is set to be between the relative dose rates of the two continuous motion intervals.

2. The dose rate control method for rotational intensity modulated radiotherapy according to claim 1, characterized in that, The formulating a field treatment plan for radiotherapy and obtaining the monitor units of each sub-field includes: Presetting an optimization algorithm model; min{F} = (D t - D p ) 2 D t = M × ∑MU × I ij Among them, D t represents the actual irradiation dose, D p represents the prescribed dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub - field; Input the known variables D p , M, I ij into the optimization algorithm model to solve the approximate optimal number of jumps MU of each sub - field for which the objective function value F tends to the minimum s1 , MU s2 , …, MU sn .

3. The dose rate control method for rotational intensity modulated radiotherapy according to claim 2, characterized in that, The determining the continuous motion interval of the linear accelerator and the transition interval between two adjacent continuous motion intervals based on the monitor units of each sub-field includes: The continuous motion interval described contains a plurality of sub - fields, and the monitor units (MU) of the continuous motion interval Q is equal to the sum of the jumps of each sub - field within the interval, and controls the linear accelerator to maintain a continuously accelerating or continuously decelerating state within the continuous motion interval; The sum of the rotation angles of all the continuous motion intervals and the sum of the rotation angles of all the transition intervals is equal to the rotation angle of the intensity-modulated arc radiotherapy.

4. A dose rate control method for rotational intensity modulated radiotherapy according to claim 3, characterized in that, The calculating the relative dose rate between two adjacent continuous motion intervals includes: According to the formula: where MU Q is the machine jump number in the continuous motion interval, degree represents the rotation angle in the continuous motion interval, and redoserate represents the relative dose rate; Calculate the relative dose rates redoserate1, redoserate2, …, redoserate for each continuous motion interval m ; When the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, the setting the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose rates of the two continuous motion intervals includes: Determine the relative dose rate redoserate of the next consecutive motion interval in two adjacent consecutive motion intervals m and the relative dose rate redoserate of the previous consecutive motion interval (m-1) whether it satisfies: or where η1 and η2 are preset values, and the value range is η1 > 9, If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to the relative dose rate redoserate (m-1) of the previous consecutive motion interval among the two adjacent consecutive motion intervals. Among them, the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

5. A dose rate control method for intensity modulated arc radiotherapy according to claim 3, characterized in that, The calculating the relative dose rate between two adjacent continuous motion intervals includes: According to the formula: wherein, MU Q is the machine skip count in the continuous motion interval, degree represents the rotation angle in the continuous motion interval, and redoserate represents the relative dose rate; Calculate the relative dose rates redoserate1, redoserate2, …, redoserate for each continuous motion interval m ; When the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, the setting the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose rates of the two continuous motion intervals includes: Determine the relative dose rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose rate redoserate of the previous continuous motion interval (m-1) to check if it satisfies: |redoserate m - redoserate (m-1) | > redoserate0, where redoserate0 is a preset relative dose rate difference threshold with a value range of redoserate0 > 9; If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to the relative dose rate redoserate (m-1) of the previous consecutive motion interval among the two adjacent consecutive motion intervals. Among them, the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

6. A method for controlling the dose rate of intensity modulated radiation therapy according to claim 4 or 5, characterized in that Including: During the intensity-modulated arc radiotherapy process, controlling the linear accelerator to maintain a continuous acceleration or continuous deceleration state within the continuous motion interval, and maintaining the same relative dose rate within the same continuous motion interval; If the relative dose rate of the transition interval is set to be between the relative dose rates of the two continuous motion intervals, controlling the linear accelerator to switch the acceleration to enter the transition interval, and maintaining the same relative dose rate within the same transition interval.

7. A dose rate control device for intensity modulated arc radiotherapy, characterized in that, Including: A treatment plan module, formulating a field treatment plan for radiotherapy according to the dose rate control mode of the continuous motion interval and the transition interval, obtaining the monitor units of each sub-field, and determining the continuous motion interval of the linear accelerator and the transition interval between two adjacent continuous motion intervals based on the monitor units of each sub-field; A relative dose rate calculation module, calculating the relative dose rate between two adjacent continuous motion intervals; A control module, when determining that the difference or ratio between the relative dose rate of the next continuous motion interval and the relative dose rate of the previous continuous motion interval is greater than or less than a preset threshold, setting the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between the relative dose rates of the two continuous motion intervals.

8. The dose rate control device for rotational intensity modulated radiotherapy according to claim 7, characterized in that, The treatment plan module includes: Optimization algorithm model module, with a preset optimization algorithm model: min{F} = (D t - D p ) 2 D t = M × ∑MU × I ij Among them, D t represents the actual irradiation dose, D p represents the prescribed dose, M represents the dose contribution matrix, MU is the monitor unit, and I ij is the intensity of each pencil beam in the sub - field; Input the known variables D p , M, I ij into the optimization algorithm model to solve the approximate optimal number of jumps MU of each sub - field when the objective function value F tends to the minimum value s1 , MU s2 , …, MU sn ; Motion interval planning module, determining the continuous motion intervals of the linear accelerator and the transition intervals between two adjacent continuous motion intervals based on the monitor units of each sub - field: The continuous motion interval described above contains multiple sub - fields, and the monitor units (MU) of the continuous motion interval Q is equal to the sum of the jumps of each sub - field within the interval, and controls the linear accelerator to maintain a continuously accelerating or continuously decelerating state within the continuous motion interval; The sum of the rotation angles of all the continuous motion intervals and the rotation angles of all the transition intervals is equal to the rotation angle of intensity - modulated arc radiotherapy.

9. The dose rate control device for rotational intensity modulated radiotherapy according to claim 7, wherein The relative dose rate calculation module calculates the relative dose rates of two adjacent continuous motion intervals, including: According to the formula: where MU Q is the machine jump number in the continuous motion interval, degree represents the rotation angle in the continuous motion interval, and redoserate represents the relative dose rate; Calculate the relative dose rates redoserate1, redoserate2, …, redoserate for each continuous motion interval m ; Determine the relative dose rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose rate redoserate of the previous continuous motion interval (m-1) whether it satisfies: or where η1 and η2 are preset values, and the value range is η1 > 9, If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent continuous motion intervals to the relative dose rate redoserate (m-1) of the previous continuous motion interval among the two adjacent continuous motion intervals, where the order of the numbers of the continuous intervals themselves is determined according to the clockwise rotation order; Alternatively, determine the relative dose rate redoserate of the next continuous motion interval in two adjacent continuous motion intervals m and the relative dose rate redoserate of the previous continuous motion interval (m-1) to check if it satisfies: |redoserate m - redoserate (m-1) | > redoserate0, where redoserate0 is a preset relative dose rate difference threshold with a value range of redoserate0 > 9; If the judgment result is yes, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to be between redoserate m and redoserate (m-1) , and the value is (redoserate m +redoserate (m-1) ) / 2. If the judgment result is no, set the relative dose rate of the transition interval between two adjacent consecutive motion intervals to the relative dose rate redoserate (m-1) of the previous consecutive motion interval among the two adjacent consecutive motion intervals. Among them, the order of the numbers of the consecutive intervals themselves is determined according to the clockwise rotation order.

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