Method and camera system for generating control data for a recording process of a medical imaging device depending on a patient's movement, as well as system

Abstract

Method for generating control data (8) for a recording process of a medical imaging device (5), in particular a magnetic resonance tomograph, comprising the steps: - successive acquisition of multiple camera images of a patient (10) by means of a camera arrangement (3) during an acquisition process of a medical image of the patient (10) by means of a primary acquisition principle of the medical imaging device (5), - Determining the patient's contours (10) in the multiple camera images, and - Generating control data (8) for the acquisition process of the medical image depending on a movement of the patient (10) detected on the basis of the contours, wherein at least a part of the multiple camera images are acquired as thermal images using a thermal imaging camera and / or based on the principle of thermography, where, based on the thermal images, a pattern of the patient's heat distribution (10) is determined as the contours, wherein by comparing with predetermined patterns a representation of a nose and / or an eye socket and / or a forehead of the patient (10) is determined as the respective pattern.

Description

[0001] The invention relates to a method for generating control data for a data acquisition process of a medical imaging device, in particular a magnetic resonance imaging (MRI) scanner. The invention also relates to a camera system configured to generate the corresponding control data, and to a system comprising the camera system and the medical imaging device. Furthermore, the invention relates to a computer program and a storage medium.

[0002] During a prolonged medical imaging process, the image may become blurred or exhibit artifacts, such as double contours, due to voluntary and / or involuntary patient movements. This can affect, for example, the principle of computed tomography (CT) scans, but especially that of magnetic resonance imaging (MRI). The likelihood of blurred or artifact-laden images increases with the duration of the scan, as it is practically impossible to prevent all patient movement.

[0003] To account for and / or compensate for patient movements during the acquisition process, a so-called "kinetic sensor apparatus" is known. The underlying principle of this apparatus involves a tracking object, such as a cube or any other geometric shape, previously positioned on the patient, for example, on the patient's head, which is then captured by a camera system. By capturing the tracking object, its position or pose relative to the camera system and / or the medical imaging device can be continuously determined. From the respective relative position or pose, the movement of the tracking object can be determined across multiple images. This movement of the tracking object, in turn, can be used to infer the movement of the patient.For example, the acquisition of the medical image is adjusted during the acquisition process according to the patient's movement. Figuratively speaking, this can mean a movement of the coordinate system underlying the medical image during the acquisition process, which attempts to compensate for the patient's movement.

[0004] A disadvantage of tracking devices is that, for practical reasons, they are usually attached to the patient's skin. This attachment, particularly to the patient's head, makes it impossible to accurately correlate the tracking device's movement with internal body movements, as the patient's skin is mobile relative to the body's internal structures. For example, when capturing a medical image of the patient's head, tensing facial muscles results in relative movement between the body surface (skin) and the internal body structure being captured by the medical image (skull or brain). This leads to inaccurate tracking of the patient's movement, which does not correspond to the movement of the internal body, in this example, the brain.This in turn leads to blurring or artifacts in the medical image of the body's interior.

[0005] The use of tracking devices permanently attached to the patient or their internal organs, such as devices attached to the patient's upper jaw or helmet-shaped devices, is not a practical alternative, particularly when treating or imaging head injuries or patients who are incapacitated. Tracking devices that can be positioned on specific body parts, such as a knee, are typically not adaptable to the anatomy of other body parts.

[0006] Publication US 2015 / 0265220A1 discloses systems, methods, and devices for removing prospective motion correction from medical imaging scans. Publication DE 102018112301A1 discloses systems, devices, and / or methods for providing motion-suppressing imaging.

[0007] It is therefore an object of the present invention to enable a more precise detection of a patient's movement during the acquisition of a medical image. In particular, it is an object of the present invention to take into account deviations in the movement of a body surface, especially the skin, and body interiors, such as the brain.

[0008] This problem is solved according to the invention by the subject matter of the independent patent claims. Advantageous embodiments with expedient further developments are the subject matter of the dependent claims.

[0009] A first aspect of the present invention relates to a method for generating control data for an acquisition process of a medical imaging device, in particular a magnetic resonance imaging (MRI) scanner. In one step of the method, several camera images of a patient are successively acquired by a camera arrangement during an acquisition process of a medical image of the patient using a primary acquisition principle of the medical imaging device. In a further step, the contours of the patient are determined in the several camera images. Depending on a movement of the patient detected based on the contours, control data for the acquisition process of the medical image is generated.

[0010] One aspect of the present invention is to capture the patient themselves using camera images. This can be done as an alternative or in addition to capturing the tracking object. By capturing the patient's contours, it becomes possible to quantify the patient's movements, particularly those of a specific body region captured by the medical image. Specifically, the contours can be used to differentiate between movements on the surface, especially the skin, and those within the body. Based on this, control data can be generated that better characterize the patient's movement and allow for corresponding adjustments to the medical image acquisition process.

[0011] The multiple camera images of the patient can be acquired continuously and / or periodically. These images can be stored as image data. In particular, the camera images can be acquired at a predetermined frame rate, such as 50 or 60 Hertz. In other words, the multiple camera images can be acquired sequentially. For example, the multiple camera images can be individual frames of a video signal. This results in a representation of the patient in the camera images at different times. The acquisition principle of the camera setup differs from the primary acquisition principle of the medical imaging device. In other words, the primary acquisition principle of the medical imaging device differs from that of a camera.In particular, the primary acquisition principle is that of magnetic resonance imaging (MRI) or computed tomography (CT). Computed tomography is based on the physical principle of X-ray imaging. However, the method is equally applicable to other acquisition principles for capturing medical images, especially those with a particularly long acquisition time.

[0012] The patient's contours are determined from multiple camera images. Specifically, contours within each image of the patient are identified in the multiple camera images. Well-known algorithms from the field of image recognition can be used for this purpose. In other words, the patient's image in each camera image can be examined for specific contours. These contours can then correspond to the contours actually present on the patient.

[0013] Patient movement can be detected or determined based on the contours. For example, movement can be detected if the position of the contours differs in successive camera images. Conversely, if the position of the contours remains constant in successive camera images, it can be determined that no patient movement is present. In a further refinement, relative movement of the contours in successive camera images can also be used to determine movement. For example, relative movement of the contours to each other can be determined as movement on the body surface, particularly the skin. Alternatively or additionally, uniform movement of contours can be determined as movement of the body's interior.

[0014] Depending on the patient's movement detected via contours, control data can be generated. This control data can characterize or describe the patient's movement. Specifically, the control data describing the patient's movement detected via contours can be transmitted to or provided to the medical imaging device. In this way, the patient's movement can be taken into account or compensated for during the acquisition process of the medical image.

[0015] According to the invention, at least some of the multiple camera images are captured as thermal images using a thermal imaging camera and / or based on the principle of thermography. In other words, some or all of the multiple camera images can be captured by a thermal imaging camera of the camera arrangement. The multiple camera images can, in other words, be captured at least partially based on the principle of thermography. One advantage of thermal images is that they can detect heat radiation emanating from the patient's interior, which shines through the body surface. In other words, by capturing thermal images of the patient, it is possible to determine, at least implicitly, the location or position of heat-radiating areas within the body. The contours of the patient in the thermal images can therefore correspond to contours within the patient's body.Consequently, the sequential acquisition of thermal images and the determination of the patient's contours within these images allow for inferences about internal body movement. In other words, internal body movements can be detected and identified based on the contours in the thermal images.

[0016] The camera system can be configured to capture both conventional optical camera images and thermal images as part of a set of multiple camera images. In this case, the camera system can therefore include at least one thermal imaging camera and at least one optical camera. This allows for the sequential acquisition of multiple thermal images as well as multiple optical images. Optical images are defined as images in the visible wavelength range and / or the near-infrared range. These optical images, for example, cover a wavelength range of 400 to 1000 nm, preferably between 800 and 900 nm. The optical camera images specifically depict the patient's body surface, particularly the skin, while the thermal images specifically depict the patient's internal organs.In this way, a separate evaluation of the respective movement of the body surface and the body interior can be carried out.

[0017] According to a training course, the plan is to use one or more cameras that are sensitive across the entire wavelength range, i.e., in both the optical and thermal imaging ranges. This allows optical and thermal images to be captured alternately or at specific time intervals.

[0018] According to a training course, thermal images are to be acquired exclusively using electromagnetic radiation in a wavelength range above 1 µm, 2 µm, or 5 µm. Alternatively or additionally, thermal images can be acquired exclusively using electromagnetic radiation in a so-called mid-infrared range, a so-called far-infrared range, or both mid- and far-infrared ranges. Accordingly, the thermal images can depend solely on the electromagnetic radiation detected in the respective wavelength range and / or infrared range. The aforementioned wavelength ranges and / or infrared ranges are particularly well-suited for imaging the patient's interior using thermal radiation.

[0019] According to a training course, it is intended that thermal images will be generated based on the patient's radiated heat output. Specifically, the individual pixels of the thermal images can be dependent on the patient's recorded heat output. The image information carried by each pixel can thus correspond to the heat output radiated by the patient in a specific area. For example, this relationship can be linear or any other type of relationship. It can also be ensured that the thermal images exclusively reflect the heat output radiated by the patient.

[0020] According to the invention, a pattern of the patient's heat distribution is determined as contours based on the thermal images. In other words, contours in the heat distribution radiated by the patient are identified or sought in the thermal images. This can be done, for example, using well-known image analysis methods, just as with optical camera images. Such patterns or contours in the heat distribution can result particularly at bones, since less heat is radiated by the patient in the area of ​​bone. In this way, contours are formed at the respective edges of bones, which are particularly easy to determine.

[0021] According to the invention, a representation of the patient's nose and / or eye socket and / or forehead is defined as the respective pattern. Predefined or pre-made patterns for the nose and / or eye socket and / or forehead can be stored in a memory. By comparing the respective patterns in the thermal images with the corresponding predefined patterns, it can be determined whether a particular pattern in the thermal images represents the patient's nose and / or eye socket and / or forehead. In other words, contours of a representation of the patient's nose and / or eye socket and / or forehead in the respective thermal images can be used to detect movement. The advantage of this is that the aforementioned body parts are highly similar in different patients and are therefore easy to identify using the thermal images.Furthermore, the aforementioned body parts may be characterized by particularly striking patterns in the thermal images.

[0022] According to further training, it is envisaged that, in addition to multiple camera images and / or additional camera images, the position of a tracking object attached to the patient is recorded, and the generation of control data is further dependent on the movement of the tracking object. In other words, it is possible to continuously record both the patient and the tracking object. For example, by determining the position and / or movement of the tracking object, a position and / or movement on the patient's body surface can be represented. Similarly, by recording the position and / or movement of the patient's contours in the multiple camera images, especially the thermal images, movement within the patient's body can be represented.By combining both methods, a particularly precise and reliable recording of the patient's movement can be determined, both on the body surface and internally. Furthermore, inconsistencies can be identified and addressed through joint analysis.

[0023] According to further training, the control data will be additionally determined based on a deviation between the movement of the tracking object and the movement detected by the contours. In other words, it can be determined whether there is a discrepancy between the patient's movement detected by the tracking object and the movement determined by the contours. Such deviations can, in particular, allow conclusions to be drawn as to whether the detected patient movement is occurring on the body surface and / or internally. In other words, the aforementioned deviation can be used to differentiate between movement on the body surface and movement internally. For example, a deviation measure can be defined that assigns a value to this deviation.Depending on the degree of deviation or the value, a distinction can then be made between movements on the body surface and movements inside the body.

[0024] According to a further training course, the acquisition process of the medical image is influenced by the patient's movement by taking control data into account. In other words, the control data relating to the patient's movement is used to adapt the acquisition process to the patient's movement. For example, the medical imaging device can be tracked during the acquisition process according to the patient's movement. This counteracts any blurring of the medical image or artifacts resulting from the patient's movement. For this purpose, it is specifically intended that the acquisition of the multiple camera images, or the determination of the contours and the patient's movement, occurs in near real time. This is ensured, for example, if the delay does not exceed 50 ms.In comparison, the time interval between two individual images at a refresh rate of 60 Hz is approximately 16 ms.

[0025] According to a further development, the medical image is modified after the acquisition process is complete by taking control data into account, depending on the patient's movement. For example, the control data is used only after the acquisition process is complete to subtract the patient's movement from the medical image or to correct the medical image for blurring and / or artifacts resulting from the patient's movement. For this purpose, the control data can, for example, be stored together with the medical image. In other words, according to this embodiment, the medical image is subsequently modified using the control data to reduce blurring and / or artifacts resulting from the patient's movement.This can be done in addition to, or instead of, the aforementioned consideration of control data during the medical image acquisition process. In other words, it can be provided that the medical image acquisition process is influenced by the patient's movement through consideration of control data, and additionally, that the medical image is influenced after the acquisition process is complete by considering control data in relation to the patient's movement.

[0026] A second aspect of the present invention relates to a camera system for providing control data for a medical imaging device, in particular a magnetic resonance tomograph, comprising a communication unit for receiving an operating signal of the medical imaging device, wherein the operating signal relates to a capture process of a medical image of a patient by means of a primary capture principle of the medical imaging device, a camera arrangement for successively capturing several camera images of the patient during the capture process of the medical image,a computing unit designed to determine the patient's contours in the multiple camera images and to generate control data for the acquisition process of the medical image depending on a movement of the patient detected based on the contours.

[0027] For example, the operating signal can indicate when such a data acquisition process is taking place or being carried out, or whether such a data acquisition process is being carried out at the respective time the operating signal is transmitted. For example, the control unit has a communication unit designed to receive the operating signal. The operating signal can be output, for example, by the medical imaging device, such as a control unit of the imaging device.

[0028] A third aspect of the invention relates to a system for capturing a medical image of a patient, comprising a medical imaging device, in particular a magnetic resonance tomograph, and the camera system according to the invention, wherein the medical imaging device is configured to transmit the operating signal to the camera system and to influence the acquisition process of the medical image by taking the control data into account.

[0029] The camera system and / or the system are each further developed by features that are already described within the scope of the inventive method. For reasons of brevity, the corresponding features are not described again here. Accordingly, the medical imaging device can be, in particular, a computed tomography scanner or a magnetic resonance imaging scanner.

[0030] The camera system and / or the installation may each include a control unit. The control unit may be configured to cause the camera system and / or the installation to carry out an embodiment of the method according to the invention. The control unit may implement the communication unit and / or the processing unit of the camera system and may be configured to control the camera arrangement.

[0031] The control unit can include a data processing device or a processor configured to initiate the execution of process steps of the method according to the invention by the camera system and / or the plant. The processor can, for example, include at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (Field Programmable Gate Array) and / or at least one DSP (Digital Signal Processor). Furthermore, the control unit can include program code configured to execute the embodiment of the method according to the invention when executed by the control unit. The program code can be stored in a data memory of the control unit.

[0032] The invention also includes a computer program, which can be directly loaded into a memory of a control unit according to the invention, with program code means to execute the steps of the method according to the invention when the program is executed in the control unit. The computer program according to the invention implements the method according to the invention on the control unit according to the invention when it is executed in the control unit.

[0033] Accordingly, the invention also includes a storage medium with electronically readable control information stored thereon, which comprises at least the aforementioned computer program and is designed such that, when the storage medium is used in a control unit according to the invention, it carries out the method according to the invention. The storage medium can, for example, be configured for digital or analog data storage. The storage medium can be write-once or multiple times, and can be volatile or non-volatile.

[0034] The invention will now be explained in more detail with reference to the accompanying drawings. Features shown in the following figure description or in the figures themselves are also considered further developments of the inventive method, the inventive control unit, or the inventive production environment.

[0035] They show: Fig. 1. A schematic block diagram of a system for capturing a medical image of a patient using a medical imaging device and a camera system; and Fig. 2 a flowchart of a method according to the invention.

[0036] Fig. Figure 1 shows a system 1 for capturing a medical image of a patient 10. The system 1 includes a medical imaging device 5, which in this example is configured as a magnetic resonance imaging (MRI) scanner. Additionally, the system includes a camera system 2 for capturing the movement of the patient 10 during the acquisition of a medical image of the patient 10 with the medical imaging device 5. In particular, the camera system 2 is configured to provide control data 8 to the medical imaging device 5. The camera system 2 includes a control unit 4 and a camera array 3.

[0037] The acquisition process of the medical image of patient 10 by the medical imaging device 5, in this case the magnetic resonance imaging (MRI) scanner, can take a certain amount of time, so movements of the patient 10 during the acquisition process cannot be ruled out. Such movements could, however, result in a blurred or artifact-laden medical image of the patient. The medical image may, in particular, be a magnetic resonance imaging scan of patient 10. To reduce such blurring or artifacts, the camera system 2 is designed to detect any movement of the patient 10 and provide corresponding control data 8 to the medical imaging device 5. Based on the control data 8, the movement of the patient 10 during the acquisition process can be compensated for by the imaging device 5.For example, the medical imaging device can be designed to track the movement using appropriate sensors to capture the medical image according to the control data 8.

[0038] The camera system 2 successively captures several camera images of the patient 10 during the acquisition process of the medical image by the medical imaging device. For example, the camera system 2 can receive an operating signal 9 from the imaging device 5, where the operating signal 9 relates to the acquisition process. For example, the operating signal 9 can indicate when such an acquisition process is taking place. For example, the control unit 4 has a communication unit 12 configured to receive the operating signal 9. The operating signal 9 can be output, for example, by the medical imaging device 5, such as a control unit 6 of the imaging device 5. The communication unit 12 can alternatively or additionally be configured to transmit the control data 8 to the medical imaging device 5. For example, the video signal has a frame rate of 60 Hz.In this case, including subsequent evaluation by the control unit 4, sufficient real-time capability can be ensured for generating the control data 8 and / or for tracking the acquisition of the medical image by the medical imaging device 5. A delay of no more than 50 ms is particularly suitable for this purpose.

[0039] The multiple camera images each depict at least a portion of the patient 10. For example, the camera images can each depict the same body part or the same body segment of the patient 10 at different times. The acquisition principle of the camera arrangement 3, or of one or more cameras of the camera arrangement 3, differs from a primary acquisition principle of the medical imaging device 5, namely, in this case, magnetic resonance imaging. The camera images can, for example, be acquired digitally in the form of image data. In particular, the acquisition of the multiple camera images occurs continuously, for example, in the form of a video signal. The multiple camera images can then be different individual frames of the video signal. A processing unit 13 of the control unit 4, or of the camera system 2, is configured to determine the contours of the patient 10 in the multiple camera images.In particular, the processing unit determines contours in the multiple camera images that represent the contours of patient 10. This can be done, in particular, using known mechanisms and methods of image analysis.

[0040] Depending on the movement of the patient 10 detected by the contours, the control data 8 are generated, in particular by the processing unit 13. For this purpose, the contours can be evaluated with regard to their position in the multiple camera images. In other words, the patient's movement is detected or determined based on the contours, especially their respective position in the multiple camera images. If the position of the contours differs in the multiple camera images, the movement can be determined based on this. For example, a movement vector for the contours can be determined based on the different positions in the different camera images. This movement vector can then be transformed into a movement vector for the patient 10, for example, by coordinate transformation.In other words, the movement vector of patient 10 can be determined from the movement vector of the contours.

[0041] Additionally, a tracking object 11, for example a cube or any other geometric body, can be detected by the camera images or by further camera images. The tracking object 11 is specifically positioned on a body surface of the patient 10. Using such a tracking system, movement of the tracking object 11 can be observed. From the movement of the tracking object 11, a movement of the patient 10, in particular of their body surface at a point where the tracking object 11 is attached, can infer.

[0042] For illumination, the medical imaging device 5 in this case has a light source 7, for example comprising at least one LED, at least one light bulb, at least one gas discharge lamp and / or at least any other light source.

[0043] The following section will explain in more detail three different embodiments of the system 1 and the camera system 2.

[0044] According to a first embodiment, the camera arrangement 3 is operated in the visible light range and / or the near-infrared range. In this case, the multiple camera images are, for example, based on light in the wavelength range of 400 to 1000 nm, preferably between 800 and 900 nm. The multiple camera images can thus each contain a representation of at least the body region or body part of the patient 10 in the aforementioned wavelength range. Additionally, in the present embodiment, the movement of the patient 10 is detected using the tracking object 11 arranged on the patient, as described above. This can be done using the same camera images or different camera images. In other words, the same or different camera images can be used to detect the patient 10 (or its body part or body region) and the tracking object 11.The movement of patient 10 is then determined based on both the contours of patient 10 and the movement of the tracking object 11. Basic information about the movement of patient 10 can be derived from the movement of the tracking object 11. Additionally, by capturing the body surface of patient 10 in an area around the tracking object 11, it can be determined whether the movement detected or recognized by the tracking object 11 involves the body's interior or only its surface. Furthermore, the movement of the contours in the multiple camera images can be evaluated and compared with the movement of the tracking object 11 and the derived movements of patient 10. From this, it can be determined to what extent the movement of the tracking object 11 represents a movement of the patient's interior.If the two different detection methods—namely, the contours of the patient 10 and the tracking object 11—detect internal body movement, the control data 8 can request or enable the medical imaging device 5 to compensate for this movement. Conversely, if the two detection methods indicate that the movement only affects the surface of the patient 10, the medical imaging device 5 can prevent or avoid compensating for this movement.

[0045] This embodiment is based on the principle that anatomical features of the patient 10, represented by the contours in the camera images, are evaluated together with the tracking object to prevent the medical imaging device 5 from incorrectly tracking phantom movements. Phantom movements are defined here specifically as movements affecting the body surface but not the interior of the patient 10. Tracking based on phantom movements would be erroneous, since the medical image typically relates, at least substantially, to the interior of the patient 10.

[0046] According to a second embodiment, the individual cameras of the camera arrangement 3 detect different wavelengths. At least one camera of the camera arrangement 3 is configured as a thermal imaging camera or, in addition to its functionality as a conventional camera, also has functionality as a thermal imaging camera. The thermal imaging camera is designed to capture or generate thermal images of the body region of the patient's body part 10. In particular, the thermal imaging camera is designed to capture several thermal images of the patient sequentially. The thermal imaging camera can, for example, be operated exclusively in the mid- and / or far-infrared range, for instance, in a wavelength range of 7 µm to 14 µm.

[0047] In addition, the camera arrangement 3 according to the second embodiment comprises at least one camera, which is essentially the same as the camera responsible for detecting the tracking object 11 in the first embodiment. This camera is referred to here as the "optical camera." In particular, the "optical camera" can be operated in the visible light range and / or in the near-infrared range, i.e., approximately between 400 nm and 1000 nm, preferably between 800 nm and 900 nm. As in the first embodiment, the optical camera determines the position or tracks the tracking object 11. Thus, the movement of the patient 10 can be inferred analogously from the movement of the tracking object 11.

[0048] In contrast, the thermal imaging camera detects the movement of patient 10 based on contours in the thermal images. This is essentially analogous to the first embodiment. The same mechanisms for image acquisition and evaluation can be applied as described for an optical camera image as in the first embodiment. Unlike an optical camera image, contours in the thermal images can be more sharply defined at characteristic points on patient 10. For example, sharp contours may be present on the nose, eye socket, and / or forehead of patient 10, enabling particularly good evaluation. The contours on the nose, eye socket, and / or forehead of patient 10 can also be compared with predetermined patterns.This allows for a refinement of contour recognition accuracy, as the aforementioned body parts (nose, eye socket, and / or forehead) often appear similar in different patients. The major difference compared to the first embodiment is that the contours in the thermal images essentially represent the patient's interior. This is because certain areas of the body surface are better able to transmit thermal radiation from the body's interior.

[0049] The camera system 2 thus records the movement of patient 10 in two ways: firstly, using the tracking object 11 located on the body surface, and secondly, using the thermal images representing the body's interior. Both sources must be filtered to combine the respective data and prevent mutual influence or interference between the two camera types of the camera arrangement 3, i.e., the at least one thermal imaging camera and the at least one optical camera. Temporal filters and / or frequency filters can be used for this purpose.

[0050] In a further embodiment, it can be provided that both camera types, i.e., the thermal imaging camera and the at least one optical camera, are operated alternately. In other words, it can be arranged that the thermal imaging camera does not acquire a thermal image while the optical camera is acquiring one of the multiple optical images, and / or that the optical camera does not acquire an optical image while acquiring one of the multiple thermal images. In other words, the different cameras, which are operated particularly in different wavelength ranges, can be operated intermittently relative to each other. Similarly, the light source 7 can, for example, also be operated in a pulsed manner. Preferably, the light source 7 is only activated to emit light during image acquisition by the at least one optical camera.In this way, a faulty influence of light from the light source 7 on the acquisition of the thermal images by the thermal imaging camera can be reduced or avoided.

[0051] A considerable amount of heat generated by the light source 7 can become uncomfortable for the patient 10 over time. This is especially true for the additional heat generated in the second embodiment. Therefore, it may be possible to deactivate the pulsing of the light source 7 during a rest phase, i.e., when no medical image acquisition process is taking place. The pulsing of the light source 7 can then be reactivated when a medical image acquisition process is initiated. During such a rest phase, the light source 7 can then be permanently switched off. This would not completely solve the problem of overheating, but would at least help to minimize it.

[0052] However, switching the device on and off can lead to other undesirable effects. Repeated heating and cooling of the apparatus would cause small shifts in the camera positions due to thermal expansion and contraction, resulting in the loss of the geometric calibration required for accurately determining the position of the tracking object 11 using the camera system 2. Therefore, it may be necessary to establish a predetermined thermal equilibrium "idle state" in which the current flowing through the light source 7 is high enough to maintain a constant temperature (to avoid loss of calibration) but low enough to prevent excessive and unnecessary heating of the medical imaging device 5, as well as the light source 7, camera assembly 3, and patient 10.

[0053] According to a third embodiment, determining the movement of patient 10 using the tracking object 11 can be completely dispensed with. In this case, all cameras of the camera system 2 or camera arrangement 3 can be configured as thermal imaging cameras. In this case, the movement of patient 10 can be determined solely based on the contours in the thermal images. This is done analogously to the first and especially the second embodiment. In particular, with such purely two-dimensional acquisition using thermal imaging cameras of the camera arrangement 3, the importance of so-called landmarks, such as the patient's nose, eye socket, and / or forehead, can increase. By comparing corresponding landmarks with predetermined patterns, three-dimensional motion information can also be obtained from the two-dimensional images.In this case, misalignment of the camera system 2 or the camera arrangement 3 due to alternating heating and cooling plays a less significant role than in the second embodiment. Therefore, the imaging of patient 10 can be improved.

[0054] Because the body surface of patient 10 is captured only to a very limited extent using thermal images in the third embodiment, this embodiment is particularly robust against movements on the body surface. Therefore, this approach of capturing movement solely based on thermal images is not limited to capturing the head of patient 10; rather, any features on any part of the body can be captured. Additionally, patient 10 could undergo the acquisition of the medical image while clothed or covered, since the thermal image is visible through a thin layer of fabric.

[0055] Currently, there is also considerable interest in another "wireless motion detection" method, the so-called PilotTone method, which is developing into a powerful tool in magnetic resonance imaging (MRI). PilotTone wirelessly measures information about cardiac movements (e.g., heartbeat) and abdominal movements (e.g., respiration), thus eliminating the need to apply ECG leads to the patient's body surface or skin or to use a breathing pillow / belt to detect respiratory movements. The information obtained by PilotTone is ultimately used by the MRI measurement control system to improve the quality of the MRI images. However, the PilotTone signal is inherently noisy and could occasionally be prone to loss of accuracy. It also does not provide an absolute measurement of motion.Capturing the movement of patient 10 using thermal images, particularly according to the third embodiment, could support the PilotTone method and improve the overall robustness of the technique, thereby compensating for some weaknesses and improving the overall reliability of the technique. Therefore, it is advantageous to couple the proposed camera system 2, particularly in conjunction with one or more thermal imaging cameras of the camera arrangement 3, with the existing respiratory sensor (PilotTone) to measure and correct the movement of patient 10 more robustly during image acquisition using magnetic resonance imaging.This approach, which combines two (or more) sources of information to arrive at a robust, “most probable” solution, is consistent with the principles underlying artificial intelligence, essentially using large amounts of data to solve complex problems.

[0056] This embodiment essentially describes how real-time motion information (namely, the control data 8) output by the camera system is used prospectively or simultaneously with the acquisition process ("live") so that the imaging device 5 (i.e., in particular the magnetic resonance imaging scanner) "follows" the movement of the patient 10 or compensates for it (e.g., by adjusting a coordinate system underlying the imaging). Thus, the real-time motion information is used prospectively or simultaneously to control the acquisition process, and the acquired medical image is already corrected when the reconstruction of the final images is performed.

[0057] Alternatively or additionally, it is possible to perform the motion correction retrospectively, i.e., after the acquisition process has been completed. In this operating mode, the control data 8 (also referred to as motion data, since it relates to the movement of the patient 10) captured by camera system 2 are recorded and stored. This allows them to be used at a later time to perform the motion correction retrospectively. If a sufficient amount of data (medical image data and motion data) was acquired during the initial scan, the motion data is applied retrospectively during the reconstruction of the medical image. Special motion correction algorithms apply the motion data to the (artifact-laden and / or blurred) medical image to make the desired motion corrections.This allows these artifacts and / or blurring in the medical image to be reduced subsequently.

[0058] In conclusion, it shows Fig. 2 Methods for generating control data 8 for a recording process of a medical imaging device 5, in particular a magnetic resonance tomograph, comprising the steps: - S1: successive acquisition of multiple camera images of a patient 10 by means of a camera arrangement 3 during an acquisition process of a medical image of the patient 10 by means of a primary acquisition principle of the medical imaging device 5, - S2: Determining the contours of patient 10 in the multiple camera images, and - S3: Generating control data 8 for the acquisition process of the medical image depending on a movement of the patient recognized based on the contours 10.

Claims

[1] Method for generating control data (8) for a recording process of a medical imaging device (5), in particular a magnetic resonance tomograph, comprising the steps: - successive acquisition of multiple camera images of a patient (10) by means of a camera arrangement (3) during an acquisition process of a medical image of the patient (10) by means of a primary acquisition principle of the medical imaging device (5), - Determining the patient's contours (10) in the multiple camera images, and - Generating control data (8) for the acquisition process of the medical image depending on a movement of the patient (10) detected on the basis of the contours, wherein at least a part of the multiple camera images are acquired as thermal images using a thermal imaging camera and / or based on the principle of thermography, where, based on the thermal images, a pattern of the patient's heat distribution (10) is determined as the contours, wherein by comparing with predetermined patterns a representation of a nose and / or an eye socket and / or a forehead of the patient (10) is determined as the respective pattern. [2] Method according to claim 1, characterized by that the thermal images are acquired exclusively using electromagnetic radiation in a wavelength range above 1 µm or above 2 µm or above 5 µm. [3] Method according to one of claims 1 or 2, characterized by , that in the thermal images image information is formed based on a heat output emitted by the patient (10). [4] Method according to any one of the preceding claims, characterized by, that in addition, in particular based on the multiple camera images and / or further camera images, a position of a tracking object which is arranged on the patient (10) is recorded and the generation of the control data (8) additionally takes place depending on a movement of the tracking object. [5] Method according to claim 4, characterized by , that the control data (8) are additionally determined depending on a deviation between the movement of the tracking object and the movement detected on the basis of the contours. [6] Method according to any one of the preceding claims, characterized by , that by taking into account the control data (8) the acquisition process of the medical image is influenced depending on the movement of the patient. [7] Method according to any one of the preceding claims, characterized by, that the medical image is only influenced after completion of the recording process by taking into account the control data (8) depending on the movement of the patient. [8] Camera system (2) for providing control data (8) for a medical imaging device (5), in particular a magnetic resonance imaging scanner, with - a communication unit (12) for receiving an operating signal (9) of the medical imaging device (5), wherein the operating signal (9) relates to a acquisition process of a medical image of a patient (10) by means of a primary acquisition principle of the medical imaging device (5), - a camera arrangement (3) for successively capturing multiple camera images of the patient (10) during the medical image acquisition process, - a computing unit configured to determine contours of the patient (10) in the multiple camera images and to generate control data (8) for the acquisition process of the medical image depending on a movement of the patient (10) recognized on the basis of the contours, wherein the camera system is configured to acquire at least a part of the multiple camera images as thermal images using a thermal imaging camera and / or based on the principle of thermography, wherein the camera system is configured to determine a pattern of heat distribution of the patient (10) as the contours on the basis of the thermal images, wherein the camera system is configured to determine a representation of a nose and / or an eye socket and / or a forehead of the patient (10) by comparison with predetermined patterns as the respective pattern. [9] Appendix (1) for capturing a medical image of a patient (10), with - a medical imaging device (5), in particular a magnetic resonance imaging scanner, and - the camera system (2) according to claim 8, wherein - the medical imaging device (5) is designed to transmit the operating signal (9) to the camera system (2) and to influence the acquisition process of the medical image by taking into account the control data (8). [10] Computer program which can be loaded directly into a memory of a control unit (4) of a camera system (2) or a plant (1), comprising program code means which cause the camera system (2) or the plant (1) to execute the steps of the method according to any one of claims 1 to 7 when the program is executed in the control unit (4). [11] Storage medium with electronically readable control information stored thereon, which includes at least one computer program according to claim 10 and is designed such that, when the storage medium is used in a control unit (4) of a camera system (2) or a plant (1), it causes the camera system (2) or the plant (1) to perform the steps of the method according to any one of claims 1 to 7.

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