X-ray imaging system and method for dental x-ray imaging

Abstract

To provide an X-ray imaging system for dental X-ray imaging.SOLUTION: An X-ray imaging system for dental X-ray imaging comprises a controller, a rotating gantry (120), an X-ray source (124) for emitting X-rays, and an X-ray imaging detector (126) for receiving the X-rays from the source. The controller is configured to control the source to emit X-ray radiation and the detector for receiving the emitted radiation in order to acquire X-ray image data. The system further comprises a depth information-producing camera (177), which is configured to produce depth information, and a position information-producing component (183), which is configured to produce position information, for acquiring at least location data of the depth information-producing camera and detector during the irradiation, synchronously with the image data to be reconstructed.SELECTED DRAWING: Figure 1a

Description

Technical Field

[0001] The present application generally relates to an X-ray imaging system and an X-ray imaging method for dental X-ray imaging.

Background Art

[0002] In known dental X-ray imaging systems used in computed tomography (CT) X-ray imaging, it is necessary to position the patient to be imaged between an X-ray source and an X-ray detector, and thus irradiate the patient with the X-ray source and receive the transmitted radiation with the X-ray detector. The received radiation is converted into the form of X-ray image data within the X-ray detector, and then this image data is used for the reconstruction of a three-dimensional (3D) CT volume of the patient.

[0003] The positioned patient is supported in the imaging position by a head support during X-ray exposure. Support is performed to keep the patient in a stationary state as long as the exposure continues. The support includes a lower shelf that supports the tip of the patient's jaw and a temple support that supports the patient's temples.

[0004] Positioning and supporting the patient is the most time-consuming task in imaging, and it is difficult to completely prevent unwanted patient movements during exposure, regardless of how correctly and carefully the patient is supported. Existing patient movements cause image artifacts throughout the reconstructed CT volume. For example, circular objects can produce sharp corners or become elliptical, sharp features can be blurred, and beam hardening artifacts are exaggerated.

Summary of the Invention

[0005] One object of the present invention is to remove the drawbacks of known solutions and enable simultaneous localization of the X-ray source and detector geometry in a mobile patient coordinate system, X-ray exposure without any support for the patient's head, indirect geometry calibration, and continuous tracking of floating geometry calibration with respect to the system or the environment during patient exposure, and to provide an X-ray imaging system therefor.

[0006] One object of the present invention is achieved by providing an imaging system, an imaging method, a computer program, and a computer-readable medium as recited in the independent claims.

[0007] Embodiments of the present invention are specified by an imaging system, an imaging method, a computer program, and a computer-readable medium as recited in the independent claims.

[0008] An X-ray imaging system for dental X-ray imaging includes a controller, a rotating gantry, an X-ray source for emitting X-rays, and an X-ray imaging detector for receiving X-rays from the source. The gantry includes the source and the detector. The controller is configured to control the source to emit X-ray radiation and the detector to receive the emitted radiation in order to acquire X-ray image data. The system further includes a depth information generating camera configured to generate depth information and a position information generating component configured to generate position information, and during irradiation, at least position data of the depth information generating camera and the detector are acquired synchronously with the image data to be reconstructed.

[0009] The X-ray imaging method for dental X-ray imaging implemented by the previous X-ray imaging system includes the step of presenting an X-ray imaging system having a depth information generation camera and a position information generation component. The method further includes the step of controlling an X-ray source and an X-ray detector within a rotating gantry by a controller of the system to acquire X-ray image data. The method further includes the step of acquiring at least the position data of the depth information generation camera and the detector synchronously with the image data to be reconstructed during the acquisition of the image data by the depth information generation camera together with the position information generation component.

[0010] A computer program including instructions, which, when the program is executed by a computer according to the previous X-ray imaging system, causes the computer to perform at least the steps of the previous X-ray imaging method.

[0011] A tangible non-volatile computer-readable storage medium includes the previous computer program.

Brief Description of the Drawings

[0012] Exemplary embodiments of the present invention will be described with reference to the following drawings.

[0013]

Figure 1a

Figure 1b

Figure 2

Figure 3

[0014] Figure 1a presents an X-ray imaging system (unit) 100 for acquiring image data from a subject, such as a patient or a calibration target, in dental X-ray imaging, for example, extraoral dental X-ray imaging. The acquired image data is used to form a two-dimensional (2D) X-ray image or to reconstruct a three-dimensional (3D) X-ray volume from at least a part of the imaged subject.

[0015] System 100 is used to perform at least computed tomography (CT) imaging, such as cone beam CT (CBCT) imaging or other types of CT imaging, which provides (generates) image data for the reconstruction of the 3D volume of the imaged subject. System 100 can also be used to perform panoramic imaging that provides image data for the formation of a panoramic 2D image, as in the system 100 presented in the figure. System 100 can also be used to perform cephalometric imaging if the system 100 includes components necessary for cephalometric imaging and provides image data for the formation of a cephalometric 2D image.

[0016] System 100 includes a rotating gantry (gantry component, rotor) 120 that embodies and supports an X-ray source (source component, head) 124 and an X-ray imaging detector (imaging detector component, head) 126, which are used for acquiring image data at least for the reconstruction of the 3D volume. The source and detector 124, 126 can also be used for acquiring image data for the formation of a panoramic 2D image and a cephalometric 2D image if the necessary components are present.

[0017] As presented in Figures 1a and 1b, gantry 120 can have a C-shape, in which case the source 124 can be attached to one end of gantry 120 and the detector 126 can be attached to the other end of gantry 120, so that the source and detector 124, 126 face each other.

[0018] The source 124 comprises an X-ray source that emits X-rays, i.e., generates an X-ray beam, for at least CT imaging, which can be CBCT imaging where the beam is a conical beam, or alternative CT imaging where the beam is a conical beam, a semi-circular conical beam, or a beam of other shapes. The source 124 can also be used for panoramic imaging.

[0019] The detector 126 comprises at least one X-ray detector, e.g., one or two X-ray detectors, that receives the X-rays (beam) emitted from the source 124 and generates image data from the X-ray-exposed, i.e., imaged, object. The received image data is used for forming a panoramic image of the object or reconstructing a 3D volume.

[0020] The one-sensor (single-sensor) detector 126 comprises a panoramic / CT combination sensor, a panoramic / CT / cephalometric combination sensor, or a panoramic / CT sensor that enables one-shot cephalometric imaging. The one-sensor detector 126 can be adjustable such that the sensor (detector 126) can be rotated and / or moved relative to the gantry 120 to be preferably positioned perpendicular to the source 124.

[0021] The two-sensor detector 126 can comprise a panoramic sensor and a CT sensor, or a cephalometric sensor that also enables panoramic imaging, and a CT sensor. The two-sensor detector 126 can be adjustable such that there are several ways to attach the sensors and it is possible to change the sensors located within the beam. The sensors used are preferably positioned perpendicular to the source 124.

[0022] Alternatively, the detector 126 can be fixed.

[0023] The gantry 120 also includes a collimator (collimator component, X-ray beam limiting) 128 for the source 124 that collimates the beam from the source 124. The collimator 128 can be attached in front of the source 124 and controls the size and shape of the beam during imaging so that the beam matches the needs of the selected imaging mode (protocol), such as a CT or panoramic imaging mode, the selected image size, and the size of the associated sensor.

[0024] The system 100 also includes a column (column component) 140 that supports the system 100 and adapts its height Z and, simultaneously, the height of the gantry 120 to the height of the subject for CT or panoramic imaging.

[0025] The system 100 may include a carriage (carriage component) 145 that forms a structure that can provide support for vertical Z movement and for other components adapted to be moved simultaneously.

[0026] When the system 100 includes the carriage 145, the column 140 includes a height adapter (adapter component) 141 that causes vertical Z movement of the carriage 145. The adapter 141 can include, for example, a height motor, gears, a threaded rod, and a telescoping or counterweighted component that realizes Z movement as telescoping or counterweighted movement. The height motor drives the other components of the adapter 141 to adapt the height of the carriage 145.

[0027] The system 100 may also include patient supports (support components) 142, 143, although not necessarily, that are used to support the subject in CT or panoramic imaging as presented in FIGS. 1a and 1b. The patient supports 142, 143 can include a lower shelf 142 attached to the carriage 145 and a forehead support 143. The lower shelf 142 can support the tip of the subject's jaw, and the forehead support 143 can support the subject's forehead or brow.

[0028] System 100 also includes an upper shelf 150 that supports the gantry 120 and enables the gantry 120 to move relative to the upper shelf 150. The upper shelf 150 can be attached to the carriage 145 by a fixed joint.

[0029] The gantry 120 can be attached to the upper shelf 150 using an attacher 151 that enables the gantry 120 to rotate about its axis of rotation 122 and to move relative to the upper shelf 150.

[0030] The carriage 145 can include a lower shelf 142, a cheek support 143, an upper shelf 150, and a gantry 120. Then, when the height adapter 141 effects Z movement, the height adapter 141 adapts the heights of components 142, 143, 150, 120.

[0031] System 100 also includes a camera 177 (camera component) that can generate depth information. The depth sensing camera 177 can include an optical camera, such as a color camera or a monochrome camera, and a depth camera, such as an infrared (IR) camera, such that either the optical camera or the depth camera functions as the main camera. Alternatively, the camera 177 can include two optical cameras, such as two color cameras or monochrome cameras, such that one of the optical cameras functions as the main camera. Alternatively, the camera 177 can include a time-of-flight (ToF) camera. The camera 177 can be attached to the gantry 120 such that at least its main optical camera is positioned in relation to the detector 126. Other cameras, namely the depth camera and non-main optical cameras in alternative configurations, can also be positioned in relation to the gantry 120, e.g., in relation to the detector 126, or, if such exist, to other components of the system 100, such as the column 140, or the carriage 145.

[0032] System 100 also includes a position information generation component 183 that can determine the position of at least the main camera, camera 177, i.e., generate position data for at least the main camera, camera 177. The position information generation component 183 can be, for example, an inertial measurement unit (IMU). The position information generation component 183 can be installed, for example, within the gantry 120 or within the column 140 of the carriage 145 as presented in FIGS. 1a and 1b if such is available.

[0033] FIG. 1b shows how the attachable 151 enables the rotational movement (R movement) of the gantry 120 up to a maximum of 400 degrees around its axis of rotation 122. This R movement can be used for CT imaging mode, panoramic imaging mode, or both imaging modes.

[0034] The attachable 151 can also enable a first linear Y movement of the gantry 120, such that its axis of rotation 122, and thus its center of rotation, can be adjusted (positioned) along the Y movement with respect to the upper shelf 150 before and during the imaging (scanning) operation of imaging, regardless of the presence or absence of irradiation. The Y movement is parallel to the upper shelf 150.

[0035] The attachable 151 can also enable a second linear X movement, such that the axis of rotation 122 can be adjusted within the plane defined by the X and Y movements before and during the imaging operation of imaging. The X movement is perpendicular to the Y movement.

[0036] The attachable 151 can also enable a third N A movement that moves the axis of rotation 122 along the beam. The N A movement of the axis of rotation 122 along the beam can be used to change the magnification within the CT and panoramic imaging modes.

[0037] The attachable 151 can also enable a fourth N movement that moves the axis of rotation 122 perpendicular to the beam.P It can be made movable. Using it, changes can be made between offset imaging and symmetric imaging in CT imaging, and then it affects the field of view (FOV).

[0038] Alternatively, instead of the fixed joints presented in FIGS. 1a and 1b, the upper shelf 150 can be attached to the column 140, or the carriage 145, if such exists, by a pivotal joint (not shown), and the pivotal joint, if such exists, enables pivotal movement of the upper shelf 150 around the column 140 (carriage 145) and relative to the patient supports 142, 143, and thus the gantry 120 is, for example, above the position where the patient to be imaged is positioned (patient supports 142, 143).

[0039] In this alternative embodiment of the system 100, the attachment 151 also enables the rotational R movement and linear movement of the gantry 120 described earlier, and thus the gantry 120 can rotate up to 400 degrees around its rotation axis 122, and the gantry 120 can move linearly relative to the upper shelf 150, for example, parallel or at a specific angle relative to the parallel direction.

[0040] In this alternative embodiment of the system 100, the attachment 151 can move with at least one linear movement, and thus the rotation axis 212, and thus the center of rotation relative to the upper shelf 150, can be adjusted along the linear movement. In this way, the rotation axis 122 can be positioned within the plane defined by the pivotal movement of the upper shelf 150 and the linear movement of the rotating gantry 120 during imaging.

[0041] The movements and required components of the alternative embodiment of the system 100 are presented accurately by the published patent application FI20145617.

[0042] System 100 also includes a rotation motor (not shown) that rotates and / or moves the gantry 120 as described above by the attachor 151 while positioning the gantry 120 above the lower shelf 142 and / or during imaging. The rotation motor can be within the gantry 120 or within the upper shelf 150.

[0043] System 100 may include a first movement motor that moves the collimator 128 and / or the detector 126 during positioning of the gantry 120 and / or during imaging. The first movement motor can be within the gantry component 120 or within the upper shelf 150.

[0044] System 100 can use R movement to read the CT detector during the imaging phase of CT imaging that results in image data of a 3D volume. System 100 can also use X movement and / or Y movement during the imaging phase of CT imaging.

[0045] System 100 can generate a projection x-ray image of the ROI such that the center of the region of interest (ROI) and the R movement coincide. The effective rotation angle (aperture) can be approximately 180 to 360 degrees, depending on System 100.

[0046] System 100 can use at least one of the R movement, X movement, and Y movement during the imaging phase of panoramic imaging that results in image data of a panoramic image.

[0047] When the upper shelf 150 is attached by a pivotal joint as described above, System 100 can use at least one of the R movement, pivotal movement, and linear movement during the imaging phases of CT and panoramic imaging.

[0048] FIG. 2 presents an x-ray imaging method 201 in CT imaging implemented by the system 100 described, for example, in the context of the previous figures.

[0049] In step 202, system 100 presents source 124, detector 126, camera 177, and position information generation component 183. The operator of system 100 activates system 100, whereupon system 100 initializes itself to obtain image data from source 126, camera data from camera 177, and position data from position information generation component 183 for use in calibrating components 124, 126, 177 and reconstructing the 3D volume of the imaged object.

[0050] In step 204, the operator, via its user interface (UI, user interface component) 178, instructs controller (control component) 370 of system 100 to perform calibration of source, detector, and camera 124, 126, 177 to obtain source / detector (SD) pair calibration data, camera calibration data, and exact (integrated) transformation data between SD pair 124, 126 and camera 177, based on at least one predetermined condition exceeding a predetermined limit, such as a specific parameter describing the state of system 100, a specific elapsed time after a previous calibration, or several implemented imaging processes. After detecting the need for calibration, the operator gives such an instruction. Alternatively, controller 370 may proactively (automatically) detect the need for calibration when at least one of the previously described conditions exceeds a predetermined limit value and perform calibration of source, detector, and camera 124, 126, 177.

[0051] System 100 calibrates SD pair 124, 126, for example, by imaging (scanning) a calibration target and mapping the target within a 3D space (CT space), and simultaneously calibrates camera 177, where the target can be visually recognized together, by imaging the target and mapping the calibration target within a local 3D space (camera space). At the same time, at this so-called zero point, controller 370 obtains transformation data based on the geometry established between source, detector, and camera 124, 126, 177 by camera 177 and position information generation component 183.

[0052] In step 206, the operator instructs the controller 370, via the UI 178, to synchronize the acquisition of image data, i.e., the imaging of the patient performed by the source and detectors 124, 126, the recording of camera data, and the acquisition of position data performed by the position information generation component 183. As a result of this step 206, the acquisition of image and position data and the recording of camera data are performed synchronously.

[0053] Steps 204 and 206 do not need to be performed every time, but these steps 204, 206 may be performed very rarely, even when compared to known calibration solutions, either automatically or by operator initiation.

[0054] In step 208, the operator instructs the patient, i.e., the subject, to attach to or be positioned at the position between the source and the detectors 124, 126 so that the patient can be imaged. The patient can be positioned by the patient supporters 142, 143. Thus, either the lower shelf 142 supports the tip of the patient's jaw, or the forehead or cheek support 143 supports the patient's forehead or cheek, or all parts of the patient supporters 142, 143 support the patient. Alternatively, the patient can be freely positioned between the source and the detectors 124, 126 without the help of the patient supporters 142, 143.

[0055] In step 210, the operator instructs the controller 370, via the UI 178, to control the system 100 to perform the necessary imaging operations by the mover 375 to acquire image data from the positioned patient, to cause the source 124 to emit X-ray radiation, and to cause the detector 126 to receive the emitted radiation during these operations.

[0056] In step 212, simultaneously, that is, during the acquisition of the image data and synchronously with the acquisition of the image data, camera 177 images the source 124, the positioned patient, or both, in order to acquire camera data, and the position information generation component 183 determines position data so as to track the position of camera 177 with respect to the object being imaged, for example the positioned patient, during the acquisition of the camera data.

[0057] In step 213, if all imaging and recording have not been completed, the method returns to step 210. Otherwise, when all the necessary data have been acquired, method 201 proceeds to the next step 214.

[0058] In step 214, after the acquisition of the necessary image data is completed, the operator instructs the patient to exit the imaging position.

[0059] In step 216, the controller 370 calculates the position data of the SD pair 124, 126 at each instant from the recorded camera data by calculating the position data of camera 177 at each instant with respect to the position of camera 177 being calibrated at the zero point by the calibration data of camera 177, and by using the calculated position data of camera 177 and the conversion data at each instant.

[0060] In step 218, the controller 370 uses the calculated position data of the SD pair 124, 126 at each instant when reconstructing the acquired image data into a 3D volume of the imaged patient.

[0061] Figure 3 presents a system 100 capable of acquiring X-ray image data and camera data used for the reconstruction of a 3D volume.

[0062] System 100 includes a controller 370 that controls the operation and movement of, for example, its components 120, 124, 126, 128, 141, 150, 151, 177, 178, 183, 374, 375, 379 so that the system 100 operates as described in the context of the previous figures.

[0063] The controller 370 includes a processor (processor component) 372 that executes instructions started by an operator (user) and / or by a computer program (software) to process data in order to execute an application. The processor 372 may include at least one processor, for example, one, two, three, or more processors.

[0064] If the processor 372 includes several processors, the processor 372 may be located only within the system 100, or within at least one separate device, or one component of the processor 372 may be located within the system 100 and another component of the processor 372 may be located within at least one separate device capable of performing the reconstruction of the 3D volume of the imaged object and the formation of the 2D image.

[0065] The controller 370 also includes a memory (memory component) 380 for storing and maintaining data. The data can be instructions, computer programs, and data files. The memory 380 includes at least one memory, for example, one, two, three, or more memories.

[0066] System 100 also includes a data transfer device (data transfer component) 374 that the controller 370 uses to send control commands, data requests, and data to at least one of components 124, 126, 128, 141, 177, 178, 183, 375, 379 within system 100, such as source 124, detector 126, mover 375, camera 177, or position information generating component 183. The data transfer device 374 also receives control commands, data requests, and data from at least one of components 124, 126, 128, 141, 177, 178, 183, 375, 379 within the controller 370's control, such as source 124, detector 126, mover 375, camera 177, or position information generating component 183. Communication between the data transfer device 374 and components 124, 126, 128, 141, 177, 178, 183, 375, 379 within system 100 is provided via wired and / or wireless connections.

[0067] The mover 375 includes a motor, driver, or other component that the controller 370 uses to cause the movement of at least one of components 120, 124, 126, 128, 141, 150, 151.

[0068] System 100 also includes a camera 177 that the controller 370 uses to acquire camera data as described in the context of the previous figures, and a position information generating component 183 that the controller uses to acquire position data.

[0069] System 100 also includes a UI 178 that enables an operator to input control commands, receive information and / or instructions, and display information. The UI 178 can include at least one of a touch screen, at least one function key, and a wired or wireless remote control. The UI 178 can be attached to the column 140 or the carriage 145 as presented in FIGS. 1a and 1b.

[0070] System 100 also includes a power supply (power supply component) 379 that enables power supply to the system 100. The power supply 379 includes a connection to at least one component for power supply to the system 100, such as an electrical plug, a battery, or a regulator.

[0071] Memory 380 stores at least a data transfer application 384 for operating (controlling) the data transfer component 374, a user interface (UI) application 388 for operating the UI 178, and a power supply application 381 for operating the power supply 379.

[0072] Memory 380 also stores a computer program (computer software, computer application) 389 that, when executed by a computer, for example, by the controller 370 in the system 100, uses at least one of the components 124, 126, 128, 141, 151, 177, 183, 375 to control the operation of the system 100 as previously described in this description and the figures.

[0073] The computer program 389, that is, its computer program code, can be stored in a tangible non-volatile (non-transitory) computer-readable medium, such as a compact disc (CD) or a universal serial bus (USB) storage device.

[0074] Here, the present invention and some of its advantages have been described with reference to the previous exemplary embodiments. It is clear that the present invention is not limited to these embodiments only and includes all possible embodiments within the scope of the following claims.

Claims

1. An X-ray imaging system (100) for dental X-ray imaging, comprising: a controller (370); a rotating gantry (120); an X-ray source (124) for emitting X-rays; an X-ray imaging detector (126) for receiving the X-rays from the X-ray source; a camera (177) for generating depth information; a geometry established between the X-ray source, the X-ray imaging detector, and the camera; and comprising: the rotating gantry comprises the X-ray source and the X-ray imaging detector (124, 126); the controller is configured to control the X-ray source to emit X-ray radiation and the X-ray imaging detector to receive the emitted X-ray radiation in order to acquire (210) X-ray image data; the camera is configured to generate (212) depth information synchronously with the X-ray image data; the X-ray imaging system further comprises a component (183) configured to generate position information for acquiring (212) at least position data of the camera and the X-ray imaging detector synchronously with the X-ray image data during X-ray irradiation, and the controller is enabled to acquire (216) position data of the X-ray source / X-ray imaging detector pair (124, 126) at each instant based on the acquired position data of the camera.

2. The camera comprises an optical camera and a depth camera, or two optical cameras, and one of the cameras belonging to the camera functions as a main camera. The X-ray imaging system according to claim 1. The X-ray imaging system according to claim 1.

3. The component is configured to determine the position of at least the main camera of the camera. The X-ray imaging system according to claim 2. The X-ray imaging system according to claim 2.

4. The camera is attached to the rotating gantry such that at least the main camera is installed in relation to the X-ray imaging detector. The X-ray imaging system according to claim 2 or 3. The X-ray imaging system according to claim 2 or 3.

5. The controller controls the camera to record (212) camera data synchronously with the acquisition of the X-ray image data during X-ray irradiation. The X-ray imaging system according to any one of claims 1 to 4. The X-ray imaging system according to any one of claims 1 to 4.

6. The controller controls calibration (204) of the camera and the X-ray source to acquire calibration data of the camera and the X-ray source before X-ray irradiation. The X-ray imaging system according to any one of claims 1 to 5.

7. The controller obtains accurate conversion data based on the geometry established between the camera, the X-ray source, and the X-ray imaging detector. The X-ray imaging system according to claim 6.

8. The controller calculates the position data of the camera at each instant regarding the position of the camera during calibration based on the calibration data of the camera, and uses the calculated position data of the camera at each instant and the conversion data to calculate the position data of the X-ray source / X-ray imaging detector pair at each instant, thereby calculating the position data of the X-ray source / X-ray imaging detector pair from the recorded camera data (216). The X-ray imaging system according to claim 7.

9. Dental imaging is cone beam computed tomography X-ray imaging. The X-ray imaging system according to any one of claims 1 to 8.

10. The controller uses the calculated position data of the X-ray source / X-ray imaging detector pair at each instant when reconstructing the acquired X-ray image data into a three-dimensional X-ray volume. The X-ray imaging system according to claim 9.

11. Before X-ray irradiation, the controller controls the synchronization (206) of the acquisition of the X-ray image data and the recording of the camera. The X-ray imaging system according to any one of claims 1 to 10.

12. An X-ray imaging method (201) for dental X-ray imaging by the X-ray imaging system (100) according to any one of claims 1 to 11, comprising: To acquire the X-ray image data, a step (210) of controlling the X-ray source (124) and the X-ray imaging detector (126) in the rotating gantry (120) by the controller (370); A step (212) of generating depth information in synchronization with the X-ray image data by the camera (177); A step (212) of acquiring the position data of the camera and the X-ray image data synchronously with the X-ray image data by the component (183) during X-ray irradiation so that the controller can acquire the position data of the X-ray source / X-ray imaging detector pair based on the acquired position data of the camera.

13. A computer program (389) comprising instructions which, when executed by a computer (100), cause the computer to perform at least the steps of the X-ray imaging method according to claim 12. Computer program (389). **Claim 14** A tangible non-transitory computer-readable storage medium comprising the computer program (389) according to claim 13.

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