Gamma knife radiotherapy system and method with respiratory gating function

Abstract

The invention discloses a gamma knife radiotherapy system and method with a respiratory gating function, and belongs to the technical field of radiotherapy. The invention discloses a gamma knife radiotherapy method with a respiratory gating function. The method comprises the following steps: performing respiratory training on a patient; collecting a respiratory movement curve of the patient; respiratory characteristics in the respiratory movement curve are extracted; determining a beam-out inspiration threshold value when the gamma knife completes beam-out and a beam-off expiration threshold value when the beam-off is completed in a respiratory cycle; increasing a beam-out inspiration threshold value as a starting threshold value when a gamma knife beam-out instruction is issued; the beam closing expiration threshold value is increased to serve as an ending threshold value when a gamma knife beam closing instruction is issued, and the starting threshold value and the ending threshold value are related to time delay from gamma knife beam output / beam closing instruction issuing to beam output / beam closing completion; in each breathing cycle after breathing of the patient is stable, when the inspiration amplitude is larger than a starting threshold value, a gamma knife beam output instruction is issued; when the expiration threshold value is smaller than the end threshold value, a gamma knife beam closing instruction is issued.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy, and more particularly to a gamma knife radiotherapy system and method with respiratory gating function. Background Art

[0002] At present, tumors are prevalent and seriously endanger human health. Whole-body gamma knife uses gamma rays to stereotactically damage or inhibit tumor tissues. It has a wide range of clinical indications, including intracranial space-occupying lesions (brain metastases, gliomas, meningiomas, pineal tumors, pituitary cell tumors, etc.), primary and metastatic lung cancer and liver cancer, pancreatic cancer, etc. It has become one of the main devices for treating malignant tumors.

[0003] After searching, a patent document with the existing publication number CN102698376A provides a passive respiratory gating system and its control method. This method monitors the changes in the patient's breathing during treatment in real time, reduces the outer boundary of the subclinical lesions to the planned target area by intervening in the patient's breathing, and ensures that the target area position changes within a smaller range during each treatment; at the same time, it improves the efficiency of radiotherapy, thereby effectively reducing the treatment time.

[0004] When using respiratory gating for radiotherapy, the characteristics of the radiotherapy equipment need to be considered; when using the gamma knife for treatment, there is a delay between issuing instructions and beam emission or beam shutoff; when using an accelerator for radiotherapy, the delay between issuing instructions and beam emission or beam shutoff is shorter and can be performed simultaneously; therefore, when using the gamma knife for treatment, it is necessary to combine the patient's respiratory curve and the response delay of the gamma knife to determine the time point of radiotherapy, avoid normal organs, and ensure the safety of patient treatment. In view of this, we propose a gamma knife radiotherapy system and method with respiratory gating function. Summary of the invention

[0005] 1. Technical problems to be solved

[0006] The purpose of the present invention is to provide a gamma knife radiotherapy system and method with respiratory gating function to solve the problems raised in the above background technology.

[0007] 2. Technical solution

[0008] The present invention is achieved through the following technical solutions:

[0009] A gamma knife radiotherapy method with respiratory gating function, including:

[0010] S1. Provide breathing training to patients;

[0011] S2, collecting the patient's respiratory movement curve;

[0012] S3, extracting respiratory features from the respiratory motion curve;

[0013] S4. According to the respiratory characteristics and tumor characteristics, the inhalation threshold when the gamma knife completes beam delivery and the exhalation threshold when the beam is closed are determined within a respiratory cycle, so that the gamma rays are always irradiated to the tumor during the radiotherapy process;

[0014] S5, increasing the inspiratory threshold for beam output as the starting threshold when the Gamma Knife beam output instruction is issued; increasing the expiratory threshold for beam closing as the ending threshold when the Gamma Knife beam closing instruction is issued, wherein the starting threshold and the ending threshold are related to the time delay from the issuance of the Gamma Knife beam output / beam closing instruction to the completion of beam output / beam closing;

[0015] S6. In each respiratory cycle after the patient's breathing stabilizes, when the inspiratory amplitude is greater than the start threshold, a Gamma Knife beam-out instruction is issued; when the expiratory threshold is less than the end threshold, a Gamma Knife beam-off instruction is issued;

[0016] S7. Accumulate the radiotherapy time in each respiratory cycle, and after reaching the target radiation time, issue the Gamma Knife beam-off command.

[0017] As an optional solution of the technical solution of this application document, in S1, through breathing training, the patient can inhale, hold his breath and exhale regularly.

[0018] As an optional solution of the technical solution of this application document, S2 includes the following sub-steps:

[0019] S201. Set a reflective sign on the patient's chest or abdomen;

[0020] S202, collecting displacement information of the reflective mark through an optical sensor;

[0021] S203, fitting the displacement information of the reflective mark into a breathing curve graph.

[0022] As an optional solution of the technical solution of this application document, the breathing characteristics include breathing cycle, breathing amplitude, inhalation duration, breath holding duration, and exhalation duration.

[0023] As an optional solution of the technical solution of this application document, in S5, the starting threshold is calculated using the following formula:

[0024]

[0025] Among them, S a is the starting threshold, is the inhalation threshold for beam emission, α is the safety factor, t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy equipment and the beam emission / beam shutoff, T iA is the duration of the inspiratory phase in a standard respiratory cycle. max is the respiratory amplitude within a standard respiratory cycle, and k is the attenuation coefficient.

[0026] As an optional solution of the technical solution of this application document, the attenuation coefficient is calculated using the following formula:

[0027]

[0028] Among them, T sum is the cumulative radiotherapy time, T target The target radiotherapy time.

[0029] As an optional solution of the technical solution of this application document, the end threshold is calculated using the following formula:

[0030]

[0031] Among them, E a is the exhalation threshold for beam closing, β is the safety factor, t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy device and the beam delivery / beam closing, T e is the duration of the exhalation phase in a standard breathing cycle, A max It is the respiratory amplitude within a standard respiratory cycle.

[0032] As an optional solution of the technical solution of this application document, the S6 also includes: displaying the patient's breathing curve.

[0033] A gamma knife radiotherapy system with respiratory gating function, comprising:

[0034] A breathing detection module is used to detect the patient's breathing amplitude and generate a breathing curve;

[0035] Breathing display module, used to display the breathing curve;

[0036] Treatment planning module, used to issue beam-on and beam-off instructions according to the respiratory curve;

[0037] The gamma knife execution module is used to receive beam-out and beam-off instructions and execute beam-out and beam-off operations.

[0038] 3. Beneficial effects

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present application determines the start threshold and the exhalation threshold according to the time delay from the issuance of the gamma knife beam-on / beam-off command to the completion of the beam-on / beam-off. When the inhalation amplitude is greater than the start threshold, the gamma knife beam-on command is issued; when the exhalation threshold is less than the end threshold, the gamma knife beam-off command is issued. This can increase the safety of radiotherapy and avoid abnormal respiratory fluctuations that may cause the gamma knife beam to be turned off untimely, thereby causing damage to normal cells.

[0041] 2. The present application gradually shortens the duration of radiotherapy during the course of radiotherapy, thereby reducing the adverse effects of increased abnormal respiratory fluctuations after prolonged breathing on radiotherapy in patients, thereby protecting normal cells.

[0042] 3. This application displays the breathing curve to the patient through the breathing display module during radiotherapy, so that the patient can perceive his or her own breathing state according to the breathing curve, avoid large fluctuations in the breathing state, and further increase the safety of radiotherapy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the overall structure of a gamma knife radiotherapy method with respiratory gating function. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0045] Embodiment 1:

[0046] See also Figure 1 The present invention provides a gamma knife radiotherapy method with respiratory gating function, comprising the following steps:

[0047] S1. Provide breathing training to patients;

[0048] S2, collecting the patient's respiratory movement curve;

[0049] S3, extracting respiratory features from the respiratory motion curve;

[0050] S4. According to the respiratory characteristics and tumor characteristics, the inhalation threshold when the gamma knife completes beam delivery and the exhalation threshold when the beam is closed are determined within a respiratory cycle, so that the gamma rays are always irradiated to the tumor during the radiotherapy process;

[0051] S5, increasing the inspiratory threshold for beam output as the starting threshold when the Gamma Knife beam output instruction is issued; increasing the expiratory threshold for beam closing as the ending threshold when the Gamma Knife beam closing instruction is issued, wherein the starting threshold and the ending threshold are related to the time delay from the issuance of the Gamma Knife beam output / beam closing instruction to the completion of beam output / beam closing;

[0052] S6. In each respiratory cycle after the patient's breathing stabilizes, when the inspiratory amplitude is greater than the start threshold, a Gamma Knife beam-out instruction is issued; when the expiratory threshold is less than the end threshold, a Gamma Knife beam-off instruction is issued;

[0053] S7. Accumulate the radiotherapy time in each respiratory cycle, and after reaching the target radiation time, issue the Gamma Knife beam-off command.

[0054] During radiotherapy, it is necessary to ensure that the radiation can be emitted and shut off in time with the patient's breathing; using respiratory gating on the accelerator can respond in time to emit and shut off the radiation, but when using respiratory gating on the gamma knife, after the beam emission and beam shutoff instructions are issued, the beam emission and beam shutoff operations need to be performed by a mechanical structure, which will cause a response lag. This method can adjust the time of issuing the beam emission and beam shutoff instructions to solve the problem of response lag.

[0055] In S1, breathing training enables patients to inhale, hold their breath, and exhale regularly, increasing the accuracy of radiotherapy.

[0056] In S2, the patient's breathing curve is acquired through the following sub-steps:

[0057] S201. Set a reflective sign on the patient's chest or abdomen;

[0058] S202, collecting displacement information of the reflective mark through an optical sensor;

[0059] S203, fitting the displacement information of the reflective mark into a breathing curve graph.

[0060] In S3, the respiratory features extracted from the respiratory motion curve include: respiratory cycle, respiratory amplitude, inhalation duration, breath holding duration, and exhalation duration.

[0061] In S4, the inspiratory threshold for beam out and the expiratory threshold for beam off mainly depend on the effect of respiration on the change of tumor position. By determining the appropriate inspiratory threshold and the expiratory threshold for beam off, the time of tumor radiotherapy in a single respiratory cycle can be increased, thereby increasing the treatment efficiency.

[0062] In S5, the start threshold is calculated using the following formula:

[0063]

[0064] Among them, S a is the starting threshold, is the inhalation threshold for beam emission, α is the safety factor, which can be 1.2, and t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy device and the beam emission / beam shutoff, T iA is the duration of the inspiratory phase in a standard respiratory cycle. max is the respiratory amplitude within a standard respiratory cycle, and k is the attenuation coefficient.

[0065] The attenuation coefficient k is calculated using the following formula:

[0066]

[0067] The end threshold is calculated using the following formula:

[0068]

[0069] Among them, E a is the exhalation threshold for beam-off, β is the safety factor, which can be 1.2, and t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy device and the beam delivery / beam shutoff, T e is the duration of the exhalation phase in a standard breathing cycle, A max It is the respiratory amplitude within a standard respiratory cycle.

[0070] The above standard breathing cycle is the average of multiple breathing cycles collected from the patient after breathing training.

[0071] In S6, when the inhalation threshold is greater than the start threshold, a beam instruction is issued, so that the inhalation threshold when the gamma knife executes beam delivery is greater than the beam delivery inhalation threshold and the start threshold; at the start threshold, there is already a gap between the radiation and normal cells, and there is a high risk in issuing a beam instruction at this time; if the patient's breathing fluctuates abnormally, exhalation occurs, and the inhalation amplitude no longer increases, a beam-off instruction needs to be issued, and before the beam-off operation is completed, the radiation may have been irradiated on normal cells, causing damage; therefore, it is necessary to set an interval between the beam delivery inhalation threshold and the start threshold to provide a safe space for the delay from issuing the beam-off instruction to the completion of beam-off during abnormal breathing;

[0072] When the exhalation threshold is less than the end threshold, the exhalation threshold of the Gamma Knife when performing beam closing is greater than the beam closing exhalation threshold; ultimately, during Gamma Knife radiotherapy, the radiation can always be irradiated to the tumor site; as the radiotherapy time accumulates, the start threshold will continue to increase, and by shortening the radiotherapy time of each respiratory cycle, the adverse effects of increased abnormal respiratory fluctuations after long-term breathing on radiotherapy are reduced, thereby protecting normal cells.

[0073] During radiotherapy, by displaying the patient's breathing curve, the patient can perceive his or her own breathing status based on the breathing curve and avoid large fluctuations in the breathing status.

[0074] Embodiment 2:

[0075] The present invention provides a gamma knife radiotherapy system with a respiratory gating function, which adopts a gamma knife radiotherapy method with a respiratory gating function described in Example 1, comprising:

[0076] A breathing detection module is used to detect the patient's breathing amplitude and generate a breathing curve;

[0077] Breathing display module, used to display the breathing curve;

[0078] Treatment planning module, used to issue beam-on and beam-off instructions according to the respiratory curve;

[0079] The gamma knife execution module is used to receive beam-out and beam-off instructions and execute beam-out and beam-off operations.

[0080] After completing the patient's breathing training, the patient is simulated and positioned by CT. After positioning is completed, the breathing detection module is used to detect the patient's breathing amplitude, generate a breathing curve, and display the breathing curve to the patient through the breathing display module. After the patient's breathing curve is stable, the treatment plan module is used to issue beam and beam off instructions. After receiving the beam and beam off instructions, the gamma knife execution module executes the beam and beam off operations to achieve radiotherapy of the patient's tumor site.

Claims

1. A gamma knife radiotherapy method with respiratory gating function, characterized in that: include: S1. Provide breathing training to patients; S2, collecting the patient's respiratory movement curve; S3, extracting respiratory features from the respiratory motion curve; S4. According to the respiratory characteristics and tumor characteristics, the inhalation threshold when the gamma knife completes beam delivery and the exhalation threshold when the beam is closed are determined within a respiratory cycle, so that the gamma rays are always irradiated to the tumor during the radiotherapy process; S5, increasing the inspiratory threshold for beam output as the starting threshold when the Gamma Knife beam output instruction is issued; increasing the expiratory threshold for beam closing as the ending threshold when the Gamma Knife beam closing instruction is issued, wherein the starting threshold and the ending threshold are related to the time delay from the issuance of the Gamma Knife beam output / beam closing instruction to the completion of beam output / beam closing; S6. In each respiratory cycle after the patient's breathing stabilizes, when the inspiratory amplitude is greater than the start threshold, a Gamma Knife beam-out instruction is issued; when the expiratory threshold is less than the end threshold, a Gamma Knife beam-off instruction is issued; S7. Accumulate the radiotherapy time in each respiratory cycle, and after reaching the target radiation time, issue the Gamma Knife beam-off command.

2. A gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: In S1, breathing training enables patients to breathe in, hold their breath, and exhale in a regular pattern.

3. The gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: The S2 comprises the following sub-steps: S201. Set a reflective sign on the patient's chest or abdomen; S202, collecting displacement information of the reflective mark through an optical sensor; S203, fitting the displacement information of the reflective mark into a breathing curve graph.

4. The gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: The breathing characteristics include breathing cycle, breathing amplitude, inhalation duration, breath holding duration, and exhalation duration.

5. The gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: In S5, the start threshold is calculated using the following formula: Among them, S a is the starting threshold, is the inhalation threshold for beam emission, α is the safety factor, t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy equipment and the beam emission / beam shutoff, T i A is the duration of the inspiratory phase in a standard respiratory cycle. max is the respiratory amplitude within a standard respiratory cycle, and k is the attenuation coefficient.

6. The gamma knife radiotherapy method with respiratory gating function according to claim 5, characterized in that: The attenuation coefficient is calculated using the following formula: Among them, T sum is the cumulative radiotherapy time, T target The target radiotherapy time.

7. The gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: The end threshold is calculated using the following formula: Among them, E a is the exhalation threshold for beam closing, β is the safety factor, t is the time delay between the issuance of the on / off command of the gamma knife radiotherapy device and the beam delivery / beam closing, T e is the duration of the exhalation phase in a standard breathing cycle, A max It is the respiratory amplitude within a standard respiratory cycle.

8. The gamma knife radiotherapy method with respiratory gating function according to claim 1, characterized in that: The S6 also includes: displaying the patient's breathing curve.

9. A gamma knife radiotherapy system with respiratory gating function, using a gamma knife radiotherapy method with respiratory gating function as claimed in any one of claims 1 to 8, characterized in that: include: A breathing detection module is used to detect the patient's breathing amplitude and generate a breathing curve; Breathing display module, used to display the breathing curve; Treatment planning module, used to issue beam-on and beam-off instructions according to the respiratory curve; The gamma knife execution module is used to receive beam-out and beam-off instructions and execute beam-out and beam-off operations.

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