System and method for planning radiation dose in cardiac radiotherapy

Abstract

System and method (400) for simulating the radiation effect of cardiac ablation includes a processor generating a cardiac simulation model configured to simulate the electrical activity of a patient's heart (402). The processor determines a simulated post-radiation state of the patient's heart by adjusting the cardiac simulation model to account for the effect of a radiation therapy plan on the simulated electrical activity of the patient's heart (404). The processor uses the adjusted cardiac simulation model to simulate the simulated post-radiation state of the heart with a stimulus that induces an arrhythmia (406), determines whether an arrhythmia is induced based on the electrical activity generated when simulating the simulated post-radiation state of the heart with the stimulus (408), and outputs an indicator of whether an arrhythmia is induced (410). The processor proposes a modification to the radiation plan if an arrhythmia is induced.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the priority of U.S. Patent Application No. 17 / 855,257, filed on June 30, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] This application generally relates to systems and methods for planning cardiac radiation therapy. Specifically, this application relates to systems and methods that simulate the effects of radiation on the electrical or electrophysiological properties of the heart and optimize or adjust the radiation dose distribution based on the simulation results to reduce or eliminate the recurrence of one or more cardiac pathological conditions. The simulation includes simulating one or more pathological conditions and checking for potential recurrences.

Background Art

[0003] Cardiac ablation is an invasive medical procedure commonly used to treat various cardiac conditions such as atrial fibrillation (AFib), atrial flutter, atrial tachycardia, ventricular tachycardia (VT), atrioventricular nodal reentrant tachycardia (AVNRT), paroxysmal supraventricular tachycardia (PSVT), Wolff - Parkinson - White syndrome, or cardiac tumors. Standard radiation cardiac procedures involve inserting a catheter into the patient's body to access the patient's heart. Then, heat or extreme cold is applied to destroy abnormal areas of the heart and prevent abnormal electrical signals from passing through the heart. This procedure is risky for at least some patients and usually requires monitoring the patient in an intensive care unit afterwards. Some of the risks associated with standard radiation ablation include bleeding or infection at the site where the catheter was inserted, vascular damage, heart valve damage, new or worsening arrhythmias, bradycardia, blood clots, stroke or heart attack, pulmonary vein stenosis, kidney damage from the contrast agent used in the procedure, and / or, in rare cases, death.

[0004] Cardiac radiation ablation (also known as cardiac radioablation) is a non-invasive form of cardiac ablation. Instead of a catheter, a radiation dose is used to target and destroy or correct abnormal areas of the heart. The use of radiation reduces some of the risks associated with invasive procedures and provides relief to high-risk cardiac patients who may have exhausted other options. However, cardiac radioablation itself has risks and its own challenges. Among them, there is a risk of destroying surrounding healthy tissue, especially in the cardiac area. This risk requires precise radiation in terms of the radiation area and dose.

[0005] Before a radiation ablation treatment, a radiotherapy treatment plan is developed. The purpose of the treatment plan is to optimize the radiation angles and / or the radiation dose at each angle to ensure that a high radiation dose reaches the target area and a low radiation dose hits the intervening tissue. SUMMARY OF THE INVENTION

[0006] According to a first aspect of the present invention, there is provided a method for simulating the radiation effect of cardiac ablation according to claim 1. According to a second aspect of the present invention, there is provided a system for simulating the radiation effect of cardiac ablation according to claim 11. Optional features are defined in the dependent claims.

[0007] The aspects described herein relate to optimizing or improving the radiation dose distribution of radiation heart ablation so as to reduce or eliminate the recurrence of cardiac arrhythmias (cardiac rhythm disorders) accompanied by cardiac pathological symptoms. A computer system can generate a patient-specific cardiac simulation model that can mimic or reproduce the electrical activity of a patient's heart. In the cardiac simulation model, the electrical activity or activation signal can be modeled using a set of parameters. The computer system can determine the effect of the radiation distribution (or radiation treatment plan) on the set of parameters that model the electrical activity or signal generated by the cardiac simulation model, and accordingly adjust the set of parameters. The adjusted cardiac simulation model represents or corresponds to the state of the heart after radiation irradiation of the heart with respect to reproducing the electrical activity of the patient's heart. The computer system can virtually stimulate a cardiac arrhythmia accompanied by cardiac pathological symptoms in the adjusted cardiac simulation model and check whether the stimulation causes a recurrence of the cardiac arrhythmia. If a recurrence of the cardiac arrhythmia is detected, the computer system can adjust the radiation distribution (or radiation treatment plan), for example, by changing the radiation dose value and / or changing the target area. The computer system can repeatedly adjust the radiation distribution and / or parameters of the cardiac simulation model and / or check for recurrence of the cardiac arrhythmia until the recurrence of the cardiac arrhythmia is achieved or not detected. If the recurrence of the pathological symptoms is not achieved or detected, the corresponding radiation distribution can be used to advance the radiation treatment plan.

[0008] According to one aspect, a method for simulating the radiation effect of cardiac ablation can include one or more processors generating a cardiac simulation model of a patient's heart based on medical images and / or electrophysiological data of the patient. The cardiac simulation model can be configured to simulate the electrical activity of the patient's heart. The method can include one or more processors determining a simulated post-radiation state of the patient's heart by adjusting the cardiac simulation model to account for the effect of a radiation treatment plan in the simulated (simulated) electrical activity of the patient's heart. The radiation treatment plan specifies the radiation dose applied to different regions of the patient's heart. The method can include one or more processors using the adjusted cardiac simulation model to simulate the simulated post-radiation state of the heart with a stimulus to induce an arrhythmia, determining whether an arrhythmia is induced based on the electrical activity generated when simulating the simulated post-radiation state of the heart with the stimulus, and / or outputting an indicator of whether an arrhythmia is induced in the simulated post-radiation state of the heart.

[0009] In some embodiments, the cardiac arrhythmia is associated with at least one of ventricular tachycardia (VT), atrial tachycardia, ventricular fibrillation, or atrial fibrillation. In some embodiments, the electrical activity is defined in a cardiac simulation model using a plurality of parameters of a plurality of electrical activity signals. Each electrical activity signal is associated with a corresponding region of the patient's heart. Adjusting the cardiac simulation model can include adjusting the parameters of the electrical activity signals associated with the regions of the patient's heart that are scheduled to receive radiation during a radiation treatment plan. Each electrical activity signal can have a plurality of phases, and each phase can be defined by one or more corresponding parameters. Adjusting the parameters of the electrical activity signals can include determining a change in the parameters of each phase of the electrical activity signal due to the effect of the corresponding radiation dose in the region of the patient's heart that is scheduled to receive radiation, and modifying the parameters of each phase of the electrical activity signal according to the determined change.

[0010] In some embodiments, the electrical activity is defined in a cardiac simulation model using one or more parameters of conduction velocity. Adjusting the cardiac simulation model can include adjusting at least one parameter of the one or more parameters of conduction velocity. In some embodiments, determining the simulated post-radiation state of the heart can include identifying the tissue of the patient's heart that is expected to become electrically inactive according to a radiation treatment plan.

[0011] In some embodiments, simulating the simulated post-radiation state of the heart using stimulation to induce a cardiac arrhythmia can include simulating virtual catheter-based stimulation in the post-radiation state of the heart.

[0012] In some embodiments, the method can further include proposing one or more modifications to a radiotherapy plan when it is determined that an arrhythmia is induced. The one or more modifications to the radiotherapy plan can include at least one of modifying the radiation dose to a first region of the heart specified in the radiotherapy plan or modifying a second region of the heart that is scheduled to receive radiation during the radiotherapy plan.

[0013] According to another aspect, a system for simulating the radiation effect of cardiac ablation can include one or more processors and a memory storing computer code instructions. The computer code instructions, when executed, cause the one or more processors to generate a cardiac simulation model of a patient's heart based on the patient's medical images and / or electrophysiological data. The cardiac simulation model can be configured to simulate the electrical activity of the patient's heart. The one or more processors can determine a simulated post-radiation state of the heart by adjusting the cardiac simulation model to account for the effect of a radiotherapy plan on the simulated electrical activity of the patient's heart. The radiotherapy plan specifies the radiation doses applied to different regions of the patient's heart. The one or more processors can use the adjusted cardiac simulation model to simulate a simulated post-radiation state of the heart with a stimulus that induces an arrhythmia, determine whether an arrhythmia is induced in the simulated post-radiation state of the patient's heart, and / or output an indicator of whether an arrhythmia is induced in the simulated post-radiation state of the patient's heart.

[0014] In some embodiments, the cardiac arrhythmia may be associated with at least one of ventricular tachycardia (VT), atrial tachycardia, ventricular fibrillation, or atrial fibrillation. In some embodiments, the electrical activity can be defined in a cardiac simulation model using a plurality of parameters of a plurality of electrical activity signals. Each electrical activity signal can be associated with a corresponding region of a patient's heart. When adjusting the cardiac simulation model, one or more processors can adjust the parameters of the electrical activity signals associated with the region of the patient's heart that is scheduled to receive radiation during a radiation treatment plan. Each electrical activity signal can have a plurality of phases, and each phase can be defined by one or more corresponding parameters. When adjusting the parameters of the electrical activity signals, one or more processors can determine the change in the parameters of each phase of the electrical activity signals due to the influence of the corresponding radiation dose in the region of the patient's heart that is scheduled to receive radiation, and can modify the parameters of each phase of the electrical activity signals according to the determined change.

[0015] In some embodiments, the electrical activity can be defined in a cardiac simulation model using one or more parameters of conduction velocity. When adjusting the cardiac simulation model, one or more processors can adjust at least one of the one or more parameters of conduction velocity. In some embodiments, when determining the simulated post-radiation state of the heart, one or more processors can identify the tissue of the patient's heart that is expected to become electrically inactive according to the radiation treatment plan.

[0016] In some embodiments, when simulating the simulated post-radiation state of the heart using a stimulus that induces a cardiac arrhythmia, one or more processors can simulate virtual catheter-based stimulation in the post-radiation state of the heart.

[0017] In some embodiments, one or more processors can further propose one or more modifications to a radiation treatment plan when determining that an arrhythmia is induced. The one or more modifications to the radiation treatment plan can include at least one of modifying the radiation dose to a first region of the heart specified in the radiation treatment plan or modifying a second region of the heart that is scheduled to receive radiation during the radiation treatment plan.

[0018] According to yet another aspect, a computer-readable medium can include stored computer code instructions. When executed, the computer code instructions can cause one or more processors to generate a cardiac simulation model of a patient's heart based on the patient's medical images and / or electrophysiological data. The cardiac simulation model can be configured to simulate the electrical activity of the patient's heart. The one or more processors can determine a simulated post-radiation state of the heart by adjusting the cardiac simulation model to account for the effect of a radiation treatment plan on the simulated electrical activity of the patient's heart. The radiation treatment plan specifies the radiation doses applied to different regions of the patient's heart. The one or more processors can use the adjusted cardiac simulation model to simulate a simulated post-radiation state of the heart with a stimulus that induces an arrhythmia, determine whether an arrhythmia is induced in the simulated post-radiation state of the patient's heart, and / or output an indicator of whether an arrhythmia is induced in the simulated post-radiation state of the patient's heart.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

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Figure 4

[0020] Part or all of the figures are schematic representations for illustrative purposes. The above information and the following detailed description include examples that illustrate various aspects and embodiments, and provide an overview or essence for understanding the nature and characteristics of the aspects and embodiments according to the claims. The figures provide further understanding as examples of various aspects and embodiments, are incorporated herein, and constitute a part thereof.

Embodiments for Carrying Out the Invention

[0021] Various concepts and embodiments regarding a method, apparatus, and system for predicting the position of the heart region in planning cardiac radiation therapy ablation will be described in more detail below. The various concepts described above and in more detail below can be implemented in any of several ways, and the concepts described are not limited to any particular implementation manner. Specific embodiments and application examples are provided mainly for illustrative purposes.

[0022] Cardiac radiation ablation potentially holds the possibility of being a safe and effective ablation strategy compared to catheter-based ablation, mainly from the perspectives of its non-invasive nature and the potential ability to target the entire myocardial layer. However, to realize this potential, various challenges need to be overcome. These challenges mainly stem from the strict requirements regarding radiation accuracy. The heart consists of multiple structures at risk, including coronary arteries and valves. These structures should be shielded from radiation (or receive relatively low radiation) to avoid permanent and significant damage to the heart. On the other hand, the treatment aims to apply a sufficiently high radiation dose to the abnormal area of the heart to destroy or at least change the characteristics (e.g., electrophysiological properties) of the abnormal area. This balance makes radiation therapy, especially in the case of the heart, a laborious and complex task.

[0023] One of the technical challenges associated with cardiac radiation therapy is to plan and evaluate the effectiveness of the radiation plan or the corresponding radiation dose distribution. In other words, given a radiation dose distribution, it is possible to determine how to evaluate its effect on the patient's heart and whether it is sufficient to cure the patient's heart. To evaluate the effectiveness of radiation, physicians usually attempt to induce VT in the patient's heart using catheter stimulation after radiation therapy. However, such an approach is invasive and, since the stimulation is performed after radiation therapy, it cannot be used for radiation dose planning.

[0024] In the present disclosure, a system and method for simulating the effect of radiation on a patient's heart are described. A cardiac simulation model configured to reproduce the electrical activity of the heart is used. The effect of radiation is modeled as a variation or adjustment of the parameters of the cardiac simulation model. Digital catheter stimulation can be applied to the adjusted cardiac simulation model to determine whether an arrhythmia can be induced. If the induction of arrhythmia is successful, the radiation dose distribution can be adjusted for better effectiveness.

[0025] FIG. 1 according to an embodiment shows a computer environment 100 as an example for planning cardiac radiotherapy. Briefly, the computer environment 100 can include a cardiac radiotherapy planning system 102, a radiation effect simulation system 104, a database 106, and / or a communication network 108. The cardiac radiotherapy planning system 102 can include an imaging device 110, an electrophysiology system 114, and / or one or more computing devices 112. The radiation effect simulation system 104 can include one or more computing devices such as computing device 116a and computing device 116b. These are hereinafter also referred to as computing device 116, either individually or collectively. The computing device 116 is configured to simulate the effect of radiation on the heart or the electrical activity of the heart. The cardiac radiotherapy planning system 102, the radiation effect simulation system 104, and the database 106 are communicatively connected to each other via the communication network 108.

[0026] The communication network 108 can include a local area network (LAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a wide area network (WAN), the Internet, a cellular network, other types of networks, or combinations thereof. The network 108 can include both wired communication and wireless communication that comply with one or more standards and / or utilize one or more transmission media. Communication through the network 108 can be performed according to various communication protocols such as TCP / IP (Transmission Control Protocol and Internet Protocol), UDP (User Datagram Protocol), IEEE communication protocols, and the like.

[0027] The cardiac radiotherapy planning system 102 can include one or more imaging devices 110, an electrophysiology system 114, and one or more computing devices 112. The imaging devices 110 can include, among other things, a computed tomography (CT) scanner, a magnetic resonance (MR) scanner, a positron emission tomography (PET) scanner, or a combination thereof. The imaging devices 110 can acquire medical images of a patient's heart through at least a portion of the cardiac cycle. In some embodiments, the imaging devices 110 can acquire a series of images representing the motion or deformation of the heart through the cardiac cycle or a portion thereof. The medical images acquired can include CT images, computed tomography angiography (CTA) images, MR images, PET images, other types of medical images, or a combination thereof.

[0028] The electrophysiology system 114 is configured to perform an electrophysiological examination of a patient, for example, to evaluate the electrical system of the heart and diagnose abnormal heartbeats or arrhythmias. The electrophysiology system 114 can include one or more catheters, a plurality of wire electrodes, and a computing device connected to the wire electrodes for recording electrical signals. A physician inserts a catheter into a vein in the patient's groin and then inserts wire electrodes into the patient's heart through the catheter and the vein. In some embodiments, the electrophysiology system 114 can include a plurality of electrocardiogram (ECG) electrodes disposed on the surface of the patient's body (e.g., chest) using a multi-electrode vest. The natural electrical pulses of the heart are transmitted through the wire electrodes and recorded by the computing device of the electrophysiology system 114. The computing device of the electrophysiology system 114 can transmit electrical signals through the electrodes to attempt to stimulate the heart tissue to produce an abnormal heart rhythm.

[0029] Computing device 112 can receive medical images from imaging device 110 and receive electrophysiological examination data from electrophysiological system 114. Computing device 112 can also obtain other medical data of the patient, such as ECG data, blood pressure data, and / or other patient data. Computing device 112 can be configured to activate or execute a radiation simulation as part of a radiation treatment plan. A radiation treatment planner can use computing device 112 to simulate one or more sets of radiation treatment parameters and determine which parameter set will result in the required radiation dose distribution. Computing device 112 can also send the acquired patient data, such as medical images and electrophysiological examination data, to database 106.

[0030] The radiation effect simulation system 104 (or each computing device 116) can be configured to generate a heart simulation model configured to mimic the patient's heart with respect to electrical activity using the acquired medical images and / or electrophysiological examination data of the patient. The effect of radiation on the patient's heart can be simulated as an adjustment of the parameters of the heart simulation model. The adjusted heart simulation model can be simulated using digital catheter stimulation to induce arrhythmia. If the induction of arrhythmia is successful, the radiation dose distribution may not be efficient for the healing of the heart. Testing for potential recurrence of arrhythmia is a predictor of the natural recurrence of arrhythmia in the patient's heart after radiation therapy. Simulation of the effects of radiation and digital stimulation can help improve the radiation treatment plan and its effectiveness. The functional characteristics of the radiation effect simulation system 104 (or each computing device 116) are described in detail below in relation to FIGS. 3-4.

[0031] In some embodiments, one or more computing devices 116 are configured to execute computer instructions to perform any of the methods described herein or each operation (act, operation, step) of the method. One or more computing devices 116 can generate and display an electronic platform for displaying information indicative of or related to the effect of radiation on the heart. The electronic platform can include a graphical user interface (GUI) through which input data is received and / or an indicator of whether the induction of arrhythmia was successful is displayed. Examples of electronic platforms generated and managed by one or more computing devices 106 can be web-based applications or websites configured to be displayed on various electronic devices such as mobile devices, tablets, personal computers, and the like.

[0032] FIG. 1 shows a network-based embodiment, but note that the methods described herein can also be performed by a single computing device that receives a patient's medical images and / or electrophysiological data and predicts the effect of radiation on the patient's heart according to the methods described herein. The computer environment 100 is not necessarily limited to the components described herein and may include additional or alternative components not shown for simplicity, and such components should also be considered within the scope of the embodiments described herein. By way of example, the computer environment 100 can include additional or alternative databases, for example, within a heart radiotherapy planning system 102 or within a radiation effect simulation system 104. Also, the number of computing devices included in the heart radiotherapy planning system 102 or the radiation effect simulation system 104 can vary according to various embodiments.

[0033] Referring to FIG. 2 according to the embodiment, a block diagram is illustrated showing an example of the system architecture of a computing system 200 that can be used to execute the method described herein. The computing system 200 can include a computing device 202. The computing device 202 can exemplify any example of the device 112 and / or the device 116 in FIG. 1. By way of illustration and not limitation, the computing device 202 can include a computed tomography (CT) scanner, a medical linear accelerator, a desktop, a laptop, a hardware computer server, a workstation, a personal digital assistant (PDA), a mobile computing device, a smartphone, a tablet, or other types of computing devices. The computing device 202 can include one or more processors 204 that execute computer code instructions, a memory 206, and a bus 208 that communicatively connects the processor 204 and the memory 206.

[0034] One or more processors 204 can include a microprocessor, a general-purpose processor, a multi-core processor, a digital signal processor (DSP), or a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or other types of processors. The one or more processors 204 can be communicatively coupled to a bus 208 for processing information. Memory 206 can include a main memory device 210, such as a random access memory (RAM) or other dynamic storage device, connected to the bus 208 for storing information and instructions to be executed by the processor 204. The main memory device 210 can be used to store temporary variables or other intermediate information during execution of instructions (e.g., related to the methods described herein such as method 400) by the processor 204. The computing device 202 can include a read-only memory (ROM) 212 or other static storage device connected to the bus 208 for storing static information and instructions for the processor 204. For example, the ROM 212 can store, for example, medical images of a patient received as an input. The ROM 212 can store computer code instructions related to or representative of the methods described herein. A storage device 214, such as a solid-state device, a magnetic disk, or an optical disk, can be connected to the bus 208 for storing information and / or instructions (or providing them as an input).

[0035] Computing device 202 may be communicatively connected to or include input device 216 and / or output device 218. Computing device 202 may be connected to output device 218 via bus 208. Output device 218 may include a display device such as a liquid crystal display (LCD), a thin film transistor LCD (TFT), an organic light emitting diode (OLED) display, an LED display, an electronic paper display, a plasma display panel (PDP), or other display for displaying information to a user. Output device 218 may include a communication interface for communicating information to other external devices. Input device 216, such as a keyboard with alphanumeric and other keys, may be connected to bus 208 to communicate information and command selections to processor 204. In another example, input device 216 may be incorporated within a display device such as a touch screen display. Input device 216 may include a cursor controller such as a mouse, trackball, or cursor direction keys to communicate direction information and command selections to processor 204 and control cursor movement on the display device.

[0036] According to various embodiments, the methods or operations (steps) described herein may be implemented as an array of computer code instructions executed by a processor 204 of a computing system 200. The array of computer code instructions can be read from another computer-readable medium, such as ROM 212 or storage device 214, into main memory device 210. Execution of the array of computer code instructions stored in main memory device 210 can cause the computing system 200 to perform the methods or operations described herein. In some embodiments, one or more processors 204 configured as a multiprocessor may be used to execute computer code instructions representing examples of the methods or processes described herein. In some other embodiments, hardwired circuitry may be used in place of or in combination with software instructions to implement examples of the methods or operations described herein. Generally, the embodiments are not limited to any particular combination of hardware circuitry and software. The functions described herein may be implemented in other types of digital electronic circuitry, in computer software, firmware, hardware, or combinations thereof.

[0037] Referring to FIG. 3 according to an embodiment, a block diagram of a radiation effect simulation system 104 shown in FIG. 1 is presented. The radiation effect simulation system 104 is a system for simulating the effects of radiation on a patient's heart, including the effects of radiation on the electrophysiological properties or electrical activity of the heart and / or the pathological effects associated with the potential recurrence of arrhythmias associated with pathological symptoms. Briefly, the radiation effect simulation system 104 can include a simulation model generator 302 that generates a heart simulation model, a radiation effect estimator 304, an arrhythmia simulator 306, an arrhythmia detector 308, and a radiation therapy plan update component 310.

[0038] The radiation effect simulation system 104 can include or be connected to a database 106. The database 106 can include image data 312, electrophysiological data 314, and / or other patient data 316. The image data 312 can include the patient's CT images, CTA images, and / or other medical images. The electrophysiological data 314 can include the patient's electrophysiological examination data indicating the electrical activity of the patient's heart through at least one cardiac cycle or a part thereof. For example, the electrophysiological data 314 can include one or more electrical signals generated by the patient's heart and recorded by the electrophysiological system 114 via one or more electrodes. The electrophysiological system 114 can record electrical signals according to invasive or non-invasive procedures. The other patient data 316 can include blood pressure data, ECG data, medical history data, demographic data, or a combination thereof.

[0039] Each of the components 302, 304, 306, 308, and / or 310 can be implemented as a software component, a hardware component, a firmware component, or a combination of software, firmware, and / or hardware. For example, any of these components can be implemented as computer code instructions executed by one or more processors, such as processor 204, to perform their respective functional steps or processes. Any of the components 302, 304, 306, 308, and / or 310 can be implemented as a digital circuit. The functional steps or processes associated with each of these components are detailed below in relation to FIG. 4.

[0040] FIG. 4 according to the embodiment shows a flowchart illustrating an embodiment of a method 400 for simulating the effect of radiation on the electrical or electrophysiological properties of the heart for cardiac radiotherapy planning. Briefly, the method 400 can include generating a cardiac simulation model of the heart (step 402). For example, one or more processors can generate a cardiac simulation model of a patient's heart based on the patient's medical images and / or electrophysiological data, and the cardiac simulation model is configured to simulate the electrical activity of the patient's heart.

[0041] The method 400 can also include determining a simulated post-radiation state of the heart by adjusting the cardiac simulation model to account for the effect of a radiotherapy plan on the simulated electrical activity of the heart (step 404). For example, one or more processors can determine a simulated post-radiation state of the patient's heart by adjusting the cardiac simulation model to account for the effect of a radiotherapy plan on the simulated electrical activity of the patient's heart, and the radiotherapy plan specifies the radiation dose applied to different regions of the patient's heart.

[0042] The method 400 can include simulating the post-radiation state of the heart using a stimulus that induces an arrhythmia (step 406). For example, one or more processors can use the adjusted cardiac simulation model to simulate the post-radiation state of the heart with a stimulus for inducing an arrhythmia.

[0043] The method 400 can include determining whether an arrhythmia is induced (step 408). For example, one or more processors can determine whether an arrhythmia is induced based on the electrical activity generated when simulating the post-radiation state of the heart using the stimulus.

[0044] Method 400 can include outputting an indicator of whether an arrhythmia is induced in a simulated post-radiation state of the heart (step 410). For example, one or more processors can output an indicator of whether an arrhythmia is induced in a simulated post-radiation state of the heart.

[0045] Method 400 can be executed by its processor, such as computing device 116 or processor 204.

[0046] Referring to FIGS. 1-4, method 400 can include one or more processors 204 or simulation model generator 302 generating a cardiac simulation model of a patient's heart using the patient's image data 312 and electrophysiological data 314 (step 402). Prior to a cardiac ablation procedure, imaging device 110 can acquire the patient's image data 312. The image data 312 can include cardiac gated CTA images, CT images, MR images, other types of medical images, or combinations thereof. Also, electrophysiology system 114 can record the patient's electrophysiological test data 314 representative of the electrical activity of the patient's heart. Computing device 112 can store the image data 312 and electrophysiological data 314 in database 106.

[0047] A physician or other medical professional can mark or outline an ROI to be irradiated on one or more of the acquired medical images of a patient, for example, based on image data 312 and electrophysiological data 314. For example, a physician can manually identify or mark the boundaries of the ROI to be irradiated (e.g., on the display of computing device 112). In some embodiments, computing device 112 can process the marked image to refine the boundaries of the ROI using, for example, an image segmentation algorithm, an object recognition algorithm, other image processing algorithms, or combinations thereof. Computing device 112 can use the refined (or original marked) ROI boundaries to identify the same ROI in other unmarked images of the patient. In some embodiments, a physician can mark the ROI in all of the acquired medical images.

[0048] In some embodiments, the ROI can include or be one or more segments of a standardized N-segment model (where N is an integer). For example, the standardized N-segment model can include a standardized AHA 17-segment heart model. The standardized N-segment model represents a standard geometric description or segmentation of the heart. Computing device 112 can identify segments, for example, based on a parametric model of the heart chambers (ventricles and atria) as described in "Four-Chamber Heart Modeling and Automatic Segmentation for 3-D Cardiac CT Volumes Using Marginal Space Learning and Steerable Features.", IEEE Transactions on Medical Imaging 27, no. 11 (November 2008) 1668-81, which is incorporated herein by reference. In some embodiments, other standardized geometric models of the heart can be used. An operator of computing device 112 can identify the ROI as one or more segments of the standardized N-segment model, for example, using a user interface presented by computing device 112.

[0049] The medical image acquired by imaging device 110 can be a two-dimensional image. Processor 204 or simulation model generator 302 can generate a patient-specific geometric model of the patient's heart using the medical image data 312. The patient-specific geometric model can include a three-dimensional (3D) model that represents the anatomical features of the patient's heart, such as shape, size, and / or various anatomical regions. For example, processor 204 or simulation model generator 302 can generate a 3D mesh of the patient's heart using the patient's medical image. Processor 204 or simulation model generator 302 can add one or more layers on top of the 3D mesh to reflect separate regions or segments of the patient's heart.

[0050] In some embodiments, the processor 204 or the simulation model generator 302 can register electrophysiological data to the generated 3D model of the patient's heart. In some embodiments, the processor 204 or the simulation model generator 302 can combine electrophysiological data to the generated 3D model of one or more patients' hearts, as described in U.S. Patent No. 9,463,072. The content of U.S. Patent No. 9,463,072 is hereby incorporated by reference. The electrical activity of the patient's heart varies spatially throughout the surface of the heart through the myocardium. In summary, the heart includes myocardial contractile cells and myocardial conductive cells. Myocardial conductive cells account for about 1 percent of the cells in the atria and ventricles, and they form the cardiac conduction system including the sinoatrial (SA) node and the atrioventricular (AV) node. Myocardial conductive cells generate electrical impulses and propagate them throughout the heart. Myocardial contractile cells account for about 99% of the cells in the atria and ventricles. These also conduct electrical impulses and are mainly responsible for contractions that pump blood throughout the body in response to the electrical impulses. Thus, the heart acts as an electromechanical system in which electrical impulses are generated by the cardiac conduction system and propagated into the myocardial contractile cells to induce contractions.

[0051] The processor 204 or the simulation model generator 302 can generate a simulation electrical model configured or structured to mimic or reproduce the electrical activity of the patient's heart. The simulation electrical model can be configured to generate signals similar to the signals of the electrophysiological data 314. The simulation electrical model can be a network of connected nodes where each node represents a block or a portion of the myocardium (or the heart). Each node in the simulation electrical model can be associated with each of the active signals and each of the conduction velocities. Each of the active signals can be a function that reaches a peak relatively quickly or rises sharply and then decays slowly over time to zero. Each active signal of the corresponding node can be defined by a set of respective parameters.

[0052] In some embodiments, each electroactive signal can have a plurality of phases, and each phase can be defined by one or more corresponding parameters. In other words, each phase of the active signal can be described from the perspective of a parameterized mathematical formulation. For example, the first phase of the active signal can be a steep gradient described or defined by a first parameterized mathematical formulation having one or more first parameters. The second phase of the active signal can represent a slow decay and can be described or defined by a second parameterized mathematical formulation having one or more second parameters.

[0053] The parameters of each active signal or its phases can be related to the underlying biology of the corresponding block or portion of the myocardium. For example, the parameters of the active signal can be set based on experimental data. Similarly, conduction velocity parameters corresponding to various nodes or various portions of the myocardium can be set based on experimental data. The results of experiments performed on the hearts of animals and / or humans can be used to set the parameters of a simulation electrical model, including the parameters of the active signal and / or the conduction velocity parameters.

[0054] Conduction velocities associated with various nodes correlate with or depend on the activation signal of the node or corresponding heart block or segment. Under healthy conditions, the steepness of the activation signal's ramp is the primary determinant of conduction velocity. The steeper the ramp, the higher the conduction velocity. In other words, how quickly an electrical signal propagates through the myocardium or network of nodes depends on how steep the activation signal's ramp is. For example, if the activation signal associated with a corresponding node reaches its peak within 100 microseconds and the activation threshold of an adjacent node is approximately half the peak amplitude, the adjacent node should be activated in approximately 50 microseconds. On the other hand, if the activation signal reaches its peak in 500 microseconds, the adjacent node should be activated within approximately 250 microseconds. In the heart, a first cell is activated or triggered (e.g., exhibits a respective activation signal) by the activation signal of an adjacent cell. Thus, the steeper the ramp of the adjacent cell's activation signal, the faster the first cell is activated, which is how the properties of one cell affect conduction velocity.

[0055] Additionally, the decay phase of the active signal depends on the ramp or peak of the active signal. The decay phase can follow a predetermined pattern described by a parameterized mathematical formulation, where the first value of the decay phase depends on the peak of the active signal. The higher the peak, the higher the first value of the decay phase of the active signal. Thus, the parameters of the mathematical formulation of the decay phase change as the peak of the active signal changes.

[0056] Processor 204 or simulation model generator 302 can model conduction velocity and activation signals based on experimental data of healthy and abnormal tissues. In particular, the parameterization function can be predefined based on experimental data of healthy and abnormal tissues. Also, processor 204 or simulation model generator 302 can use, for example, a lookup table or other data structure that holds parameter values for various tissue states (e.g., among others, healthy tissue, tissue showing VT, tissue showing AFib, tissue showing atrial fibrillation, tissue showing atrial tachycardia, tissue showing AVNRT, tissue showing PSVT, tissue related to Wolff-Parkinson-White syndrome, or tumor tissue) to set the conduction velocity parameters and the parameterization function or the parameter values for each phase. Processor 204 or simulation model generator 302 can identify the nodes corresponding to the abnormal tissue based on the registration of the simulation electrical model to the 3D model of the patient's heart. Specifically, processor 204 or simulation model generator 302 can identify the nodes related to the ROI and appropriately model their parameters. Processor 204 or simulation model generator 302 can analyze the electrophysiological data 314 to extract the measured values of the electrical activity in the patient's heart. The measured values of the electrical activity can include the measured values extracted from ECG data such as the total activation time of the left or right ventricle, QRS duration, electrical axis, QT interval duration, site-specific activation time, and / or the voltage values measured by a catheter device as part of the electroanatomical mapping. One or more processors 204 or simulation model generators 302 can simulate the corresponding measured values of the electrical activity and compare them with the measured values extracted from the electrophysiological data 314. One or more processors 204 or simulation model generators 302 can modify the conduction velocity and activation signals to minimize the difference between the simulated measured values and the data-based measured values of the electrical activity. For example, the optimal value of the conduction velocity in one region of the heart can be estimated using an iterative algorithm such as BOBYQA.Briefly, multiple candidate values for the conduction velocity can be selected, and for each selection, corresponding simulated measurement values of the electrical activity can be generated. Based on which conduction velocity value generates a simulated measurement value of the electrical activity that is closest to the measurement value based on the data, new candidate values can be generated. This algorithm can terminate when the difference between the simulated measurement value of the electrical activity and the measurement value based on the data falls below a specific threshold or when the maximum number of candidates has been generated. Additional methods for modifying the conduction velocity and the activation signal to reduce the difference between the simulated measurement value of the electrical activity and the measurement value based on the data are disclosed in U.S. Patent Nos. 10,733,910, 10,483,005, 10,241,968, and 10,141,077, which are hereby incorporated by reference.

[0057] Theoretically, the nodes of the simulation electrical model can represent individual cells of the heart. However, implementing a simulation electrical model at the cellular level results in a very complex model. Modeling the cardiac electrical system at a coarser granularity (e.g., each node corresponds to an individual myocardial block or section) results in a model that is not as complex while still providing an accurate modeling. Typically, adjacent healthy cells of the same type (e.g., myocardial contractile cells) have similar electrical properties.

[0058] The processor 204 or the simulation model generator 302 can register the simulation electrical model to a geometry (or 3D) model. Each node in the simulation electrical model is mapped to its position in the 3D model. The cardiac simulation model includes the 3D model and the simulation electrical model after registration. In some embodiments, the processor 204 or the simulation model generator 302 can use other patient data 316 to generate a cardiac simulation model of the patient's heart. For example, the processor 204 or the simulation model generator 302 can estimate one or more model parameters using the patient's age or the patient's medical history.

[0059] Method 400 can include the processor 204 or the radiation effect estimator 304 determining a simulated post - radiation state of the patient's heart by adjusting a heart simulation model to account for the effect of a radiation treatment plan on the simulated electrical activity of the patient's heart (step 404). The radiation treatment plan can include a radiation dose irradiation profile that specifies the radiation dose applied to different regions of the patient's heart. The radiation treatment plan may not be a complete plan at this stage. The radiation effect estimator 304 can receive the radiation treatment plan or the radiation dose irradiation profile from the heart radiation treatment planning system 102 or the computing device 112. In some embodiments, the radiation dose irradiation profile can be the radiation dose prescribed by the patient's physician. The radiation effect estimator 304 assumes that radiation is delivered according to the radiation dose irradiation profile and estimates the effect of the assumed delivered radiation on the electrical characteristics or electrical activity of the patient's heart.

[0060] The effect of radiation in the ROI or target volume can be simulated as a change in the electrophysiological properties of the heart tissue. For example, radiation induces upregulation of cardiac conduction proteins such as NaV1.5 and Cx43, which can be modeled as an increase in conduction velocity. The radiation dose-dependent increase in conduction velocity in the ROI is illustrated, for example, in FIG. 3 of Zhang, David M., Rachita Navara, Tiankai Yin, Jeffrey Szymanski, Uri Goldsztejn, Camryn Kenkel, Adam Lang, et al., “Cardiac Radiotherapy Induces Electrical Conduction Reprogramming in the Absence of Transmural Fibrosis,” Nature Communications 12, no. 1 (December 2021): 5558, which is hereinafter referred to as “Zhang”. Also, the radiation effect estimator 304 can model the new fibrosis potentially generated at high levels of radiation as a reduction in conduction velocity or even as a zero conduction velocity.

[0061] At least the experimental results published in Zhang may indicate that radiation increases the conduction velocity in the viable myocardium. Also, relatively high levels of radiation dose cause cell death and render electrically inactive. In other words, when the radiation dose applied to the heart tissue exceeds a given threshold, the tissue dies and becomes electrically inactive (e.g., does not respond to electrical simulation without electrical capture or propagation of electrical impulses). The radiation dose threshold can be determined from experimental results. Typically, the experimental results may include the measured changes in conduction velocity for multiple irradiation doses.

[0062] The processor 204 or the radiation effect estimator 304 can interpolate experimentally measured values. The processor 204 or the radiation effect estimator 304 can estimate or identify a radiation dose threshold leading to fibrosis or necrotic tissue. The interpolated experimental results with the identified threshold can be held in one or more data structures, such as one or more lookup tables or linked lists. The data structure can hold a mapping between a radiation dose level (or value) and a corresponding change in conduction velocity (or corresponding conduction velocity). The data structure can also hold a mapping between a radiation dose level (or value) and a corresponding change in activation signal parameter (or corresponding activation signal parameter). The mapping can include corresponding changes in parameters of each phase of the activation signal parameter (or corresponding parameters of each phase of the activation signal). Variations in the activation signal parameter (with respect to the radiation dose level) can be estimated from variations in the conduction velocity or defined based on experimental results measuring changes in the activation signal parameter.

[0063] The processor 204 or the radiation effect estimator 304 can identify nodes of the simulation electrical model belonging to the ROI, for example, based on registration of the simulation electrical model to the 3D model, and determine the radiation dose associated with the nodes or corresponding blocks or parts of the heart based on the radiation dose distribution. For each node within the ROI, the processor 204 or the radiation effect estimator 304 can determine changes in conduction velocity and changes in activation signal parameter based on the corresponding radiation dose and one or more mappings held within one or more data structures. The processor 204 or the radiation effect estimator 304 can update the conduction velocity and parameters of the activation signal for each node within the ROI. If the activation signal is parameterized for each phase, the processor 204 or the radiation effect estimator 304 can determine changes in the parameter for each phase of the activation signal and update the phase parameter accordingly.

[0064] Updating or adjusting the conduction velocity and parameters of the activation signal results in an updated or adjusted cardiac simulation model that reflects the effect of the "irradiated" radiation on the electrical properties (or electrical activity) of the heart. In other words, the updated or adjusted cardiac simulation model represents the simulated post-irradiation state of the patient's heart as if it had been irradiated according to the radiation distribution (or radiotherapy treatment plan). The initial conduction velocity and initial activation signal correspond to the pre-simulated radiation state, while the adjusted conduction velocity and adjusted activation signal correspond to the simulated post-irradiation state of the patient's heart.

[0065] Method 400 can include the processor 204 or the arrhythmia simulator 306 simulating the simulated post-irradiation state of the patient's heart using stimuli that induce an arrhythmia (step 406). The arrhythmia can be associated with at least one of ventricular tachycardia (VT), atrial tachycardia, ventricular fibrillation, atrial fibrillation, or other cardiac pathological conditions. The processor 204 or the arrhythmia simulator 306 can apply one or more digital catheter-based stimuli to the post-irradiation state of the heart. For example, in practice, a physician would use a catheter to stimulate the heart with a rapid series of stimuli to induce VT. If the radiation has not completely cured the heart, the heart begins to contract erratically, indicating induced VT. Induced VT is a strong predictor of spontaneous VT after radiation.

[0066] The processor 204 or the arrhythmia simulator 306 can digitally simulate the presence of a catheter that conveys very fast pacing to the cardiac simulation model. The digital simulation of the presence of the catheter can include applying a high-speed pulse train to one or more nodes of the cardiac simulation model. The nodes to which the high-speed pulse train is applied can depend on the type of arrhythmia to be induced. For example, in the case of VT, the nodes to be stimulated correspond to the tissue of the left or right ventricle. In the case of atrial tachycardia, the nodes to be stimulated correspond to the tissue of either the left or right atrium.

[0067] The method 400 may include the processor 204 or the rhythm disorder detector 308 determining whether a cardiac rhythm disorder is induced in the simulated post-irradiation state of the heart (step 408). The processor 204 or the rhythm disorder detector 308 may determine whether a cardiac rhythm disorder is induced in the simulated post-irradiation state of the heart based on electrical activity generated when simulating the simulated post-irradiation state of the heart using stimulation. The processor 204 or the rhythm disorder detector 308 may determine or calculate a simulated ECG signal of the cardiac simulation model, for example, as described in U.S. Patent No. 9,463,072, which is incorporated herein by reference. The processor 204 or the rhythm disorder detector 308 may analyze the simulated ECG signal to determine whether a cardiac rhythm disorder is induced in the simulated post-irradiation state of the heart.

[0068] In some embodiments, the processor 204 or the rhythm disorder detector 308 can determine the frequency, period, or autocorrelation signal of the simulated ECG signal. If the frequency, period, or autocorrelation signal does not indicate a normal-period simulated ECG signal, the processor 204 or the rhythm disorder detector 308 can infer that a cardiac rhythm disorder will be induced in the simulated post-irradiation state of the heart. If a cardiac rhythm disorder is induced, this is a strong predictor that the radiation therapy treatment plan will not be effective in healing the heart. In such cases, the radiation treatment plan should be adjusted, or, if the patient has already received radiation according to the simulated radiation treatment plan, the patient should receive additional radiation sessions, for example, with a new radiation treatment plan.

[0069] Method 400 can include the processor 204 or the radiation therapy plan update component 310 outputting an indicator of whether an arrhythmia is induced in the simulated post-radiation state of the heart. In some embodiments, the processor 204 or the radiation therapy plan update component 310 can cause a display device, such as the output device 218, to display a simulated ECG signal. A physician can check whether an arrhythmia has been induced based on the simulated ECG signal. In some embodiments, the processor 204 or the radiation therapy plan update component 310 can display a text or visual indicator indicating whether an arrhythmia has been induced. The processor 204 or the radiation therapy plan update component 310 can output an audio signal indicating whether an arrhythmia has been induced.

[0070] In some embodiments, the processor 204 or the radiotherapy plan update component 310 can recommend or propose one or more modifications to the radiotherapy plan when it determines that an arrhythmia is induced. The modifications can include modifying the radiation dose to the heart tissue or ROI specified in the radiotherapy plan, or modifying (e.g., expanding) the ROI that is scheduled to receive radiation during the radiotherapy plan. For example, the processor 204 or the radiotherapy plan update component 310 can examine the electrical activities of various nodes of the heart simulation model when stimulated to induce an arrhythmia. The processor 204 or the radiotherapy plan update component 310 can identify abnormal tissue in the ROI in the post-radiation state based on the electrical activities of the corresponding nodes. If the electrical activities of some nodes are abnormal, the processor 204 or the radiotherapy plan update component 310 can identify the nodes as abnormal and recommend increasing the radiation dose at the corresponding positions or parts within the heart. The processor 204 or the radiotherapy plan update component 310 can examine the electrical activities of the nodes corresponding to the tissue around the ROI. If the electrical activity of the node or the corresponding tissue is determined to be abnormal or disordered, the processor 204 or the radiotherapy plan update component 310 can identify the tissue as abnormal or unhealthy and recommend expanding the ROI to include the surrounding tissue.

[0071] After the radiotherapy plan (or radiation dose distribution) is updated, steps 404-410 can be repeated using the updated radiotherapy plan (or radiation dose distribution). In some embodiments, the processor 204 can execute steps 404-410 for a plurality of radiotherapy plans, select a plan that maximizes the likelihood of early termination of the arrhythmia (or the corresponding pathological symptom), and apply it to the patient. A radiation plan that maximizes the likelihood of early termination of VT is selected for execution on the patient. To estimate the likelihood of early termination of an arrhythmia (e.g., VT), one possible approach is to count the number of various programmed stimulation strategies that result in a sustained or non-sustained arrhythmia in the simulated post-radiation state. The processor 204 can identify the radiotherapy plan with the fewest number of stimuli that induce an arrhythmia as the plan that maximizes the likelihood of early termination of the arrhythmia (or the corresponding pathological symptom).

[0072] In some embodiments, the processor 204 or the radiotherapy plan update component 310 can reduce the ROI (or reduce the radiation dose) if it is determined that the arrhythmia is not induced. The processor 204 can execute steps 404-410 for the updated treatment plan to determine whether an arrhythmia is induced. The processor 204 can continue to reduce the ROI (or continue to reduce the radiation dose) and repeat steps 404-410 until an arrhythmia begins to be induced. The processor 204 can select the treatment plan with the smallest ROI (or the minimum radiation dose) that did not result in the induction of an arrhythmia. In some embodiments, the radiation dose to at least some of the tissues within the ROI changes the electrical properties of the tissue without destroying the tissue or rendering the tissue electrically inactive.

[0073] In some embodiments, method 400 can be used after radiation or during a radiation treatment. In such cases, if ECG measurements are available during the intervention, the estimated conduction velocity in step 404 is further optimized after each radiation dose irradiation to match the ECG-based metric. For example, the conduction velocity at each site point of the heart can be scaled by a factor k that reduces the mismatch between the simulated ECG and the measured ECG. In some embodiments, a first dose irradiation session is performed, followed by ECG measurements and corresponding updates of the post-radiation state of the heart. The updated post-radiation state of the heart is used to optimize the dose irradiation in subsequent sessions.

[0074] It goes without saying that the embodiments discussed herein are provided for illustrative purposes and should not be construed in a limiting sense. For example, other techniques can be used to estimate or adjust the effect of radiation on the electrical properties of the heart. Also, other types of criteria can be used to determine whether an arrhythmia is included in the simulated post-radiation state.

[0075] Each method described in this disclosure, such as method 400 of FIG. 4, can be executed by computer code instructions stored in a computer-readable medium. When the computer code instructions are executed by one or more processors of a computing device, the computing device can be made to execute the method.

[0076] Although the present disclosure has been specifically shown and described with reference to specific embodiments, it should be understood by those of ordinary skill in the art that various changes in form and detail can be made without departing from the spirit and scope of the invention described in this disclosure.

[0077] Although this disclosure includes many details of specific embodiments, these should not be construed as limitations on the scope of any invention or the scope of the claims, but rather as descriptions of features specific to particular embodiments of a particular invention. Certain features described herein in the context of separate embodiments may also be implemented in combination in one embodiment. Conversely, the various features described in the context of one embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. Further, even if features are described above as acting in a particular combination and are initially claimed as such, one or more features based on the claimed combination may in some cases be disassociated from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination.

[0078] Similarly, although operations are shown in the drawings in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order to achieve the desired result, or that all of the illustrated operations be performed. In certain circumstances, multitasking and parallel processing may be advantageous. Further, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described may generally be integrated into a single software product or packaged into multiple software products.

[0079] With respect to "or", "or" may be construed as inclusive such that any term described using "or" may indicate any of the recited terms alone, two or more, and all.

[0080] The above describes specific embodiments of the subject matter. Other embodiments are within the scope of the claims. In some cases, the functions recited in the claims may be performed in a different order and still achieve desirable results. Additionally, the processes shown in the accompanying figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing may be advantageous.

Claims

1. A method for simulating the radiation effect of cardiac ablation, comprising: one or more processors generating a cardiac simulation model of the patient's heart based on medical images and / or electrophysiological data of the patient; the cardiac simulation model being configured to simulate the electrical activity of the patient's heart; the one or more processors determining a simulated post-radiation state of the patient's heart by adjusting the cardiac simulation model to account for the effect of a radiation treatment plan on the simulated electrical activity of the patient's heart; the radiation treatment plan specifying the radiation dose applied to different regions of the patient's heart; the one or more processors using the adjusted cardiac simulation model to simulate the simulated post-radiation state of the heart with stimulation to induce arrhythmia; the one or more processors determining whether the arrhythmia is induced based on the electrical activity generated when simulating the simulated post-radiation state of the heart with the stimulation; the one or more processors outputting an indicator of whether the arrhythmia is induced in the simulated post-radiation state of the heart. A method comprising the above steps.

2. The method according to claim 1, wherein the arrhythmia is related to at least one of ventricular tachycardia (VT), atrial tachycardia, ventricular fibrillation, or atrial fibrillation.

3. The electrical activity is defined in the cardiac simulation model using parameters of a plurality of electrical activity signals, each of the electrical activity signals being associated with a corresponding region of the patient's heart; Adjusting the cardiac simulation model comprises: adjusting the parameters of the electrical activity signal associated with the region of the patient's heart that is scheduled to receive radiation during the radiation treatment plan. The method according to claim 1 or 2.

4. The electrical activity signal has a plurality of phases, each of the phases being defined by one or more corresponding parameters; Adjusting the parameters of the electrical activity signal comprises: determining the change in the parameters of each of the phases of the electrical activity signal due to the effect of the corresponding radiation dose in the region of the patient's heart that is scheduled to receive radiation. ​ modifying the parameters of the respective phases of the electrical activity signal according to the determined change The method according to claim 3

5. The method according to any one of claims 1 to 4, wherein the electrical activity is defined in the cardiac simulation model using one or more parameters of a conduction velocity

6. Adjusting the cardiac simulation model comprises adjusting at least one parameter of the one or more parameters of the conduction velocity The method according to claim 5

7. Determining the simulated post-radiation state of the heart comprises identifying tissue of the patient's heart that is expected to become electrically inactive according to the radiotherapy plan The method according to any one of claims 1 to 6

8. Simulating the simulated post-radiation state of the heart using the stimulation to induce the cardiac arrhythmia comprises simulating virtual catheter-based stimulation in the post-radiation state of the heart The method according to any one of claims 1 to 7

9. The method according to any one of claims 1 to 8, further comprising proposing one or more modifications to the radiotherapy plan when it is determined that the cardiac arrhythmia is induced

10. The one or more modifications to the radiotherapy plan are modifying the radiation dose to a first region of the heart specified in the radiotherapy plan, or modifying a second region of the heart that is scheduled to receive radiation during the radiotherapy plan, including at least one of The method according to claim 9

11. A system for simulating the radiation effect of cardiac ablation, comprising one or more processors and a memory storing computer code instructions The computer code instructions, when executed, cause the one or more processors to generate a cardiac simulation model of the patient's heart based on the patient's medical images and / or electrophysiological data The cardiac simulation model is configured to simulate the electrical activity of the patient's heart determine the simulated post-radiation state of the heart by adjusting the cardiac simulation model to account for the effect of a radiotherapy plan on the simulated electrical activity of the patient's heart The radiation treatment plan specifies the radiation doses applied to different regions of the patient's heart, uses the adjusted heart simulation model to simulate the post-simulated radiation state of the heart with stimuli that induce arrhythmia, determines whether arrhythmia is induced in the post-simulated radiation state of the patient's heart, outputs an indicator of whether arrhythmia is induced in the post-simulated radiation state of the patient's heart, system.

12. The system according to claim 11, wherein the arrhythmia is related to at least one of ventricular tachycardia (VT), atrial tachycardia, ventricular fibrillation, or atrial fibrillation.

13. The electrical activity is defined in the heart simulation model using a plurality of parameters of a plurality of electrical activity signals, and each of the electrical activity signals is associated with a corresponding region of the patient's heart, when adjusting the heart simulation model, adjusting the parameters of the electrical activity signal associated with the region of the patient's heart that is scheduled to receive radiation during the radiation treatment plan. The system according to claim 11 or 12.

14. Each of the electrical activity signals has a plurality of phases, and each of the phases is defined by one or more corresponding parameters, when adjusting the parameters of the electrical activity signal, the one or more processors determine changes in the parameters of each of the phases of the electrical activity signal due to the influence of the corresponding radiation dose in the region of the patient's heart that is scheduled to receive radiation, configured to modify the parameters of each of the phases of the electrical activity signal according to the determined changes. The system according to claim 13.

15. The system according to any one of claims 11 to 14, wherein the electrical activity is defined in the heart simulation model using one or more parameters of conduction velocity.

16. when adjusting the heart simulation model, the one or more processors are configured to adjust at least one of the one or more parameters of the conduction velocity. The system according to claim 15.

17. when determining the post-simulated radiation state of the heart, the one or more processors configured to identify the tissue of the patient's heart that is expected to become electrically inactive according to the radiotherapy plan The system according to any one of claims 11 to 16

18. When simulating the post-simulated radiation state of the heart using the stimulus that induces the arrhythmia, the one or more processors configured to simulate virtual catheter-based stimulation in the post-radiation state of the patient's heart The system according to any one of claims 11 to 17

19. The one or more processors further configured to propose one or more modifications to the radiotherapy plan when it is determined that the arrhythmia is induced The system according to any one of claims 11 to 18

20. The one or more modifications to the radiotherapy plan modifying the radiation dose to a first region of the heart specified in the radiotherapy plan, or modifying a second region of the heart that is scheduled to receive radiation during the radiotherapy plan, including at least one of the above The system according to claim 19

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