Imaging system for a radiotherapy device

Abstract

Disclosed herein is an imaging system for a radiation therapy device configured to provide therapy radiation to a patient via a therapy radiation source. The imaging system includes an imaging radiation source, a CBCT panel detector, and a CT detector, wherein the imaging radiation source is configured to be adjustable such that in a first configuration the imaging radiation source is configured to emit imaging radiation toward the CT detector and in a second configuration the imaging radiation source is configured to emit imaging radiation toward the CBCT detector.

Description

Technical Field

[0001] This disclosure relates to imaging systems and methods for use in radiotherapy equipment. Background Technology

[0002] Radiation therapy can be described as the treatment of a human or animal body using ionizing radiation (such as X-rays). Radiation therapy is commonly used to treat tumors within a patient or subject. In this type of treatment, ionizing radiation is used to irradiate and thus destroy or damage the cells that form the tumor. However, in order to deliver a prescribed dose to a tumor or other target area within the subject's body, the radiation must pass through healthy tissue, irradiating it and thus potentially damaging it in the process. The overall goal in this field is to minimize the dose received by healthy tissue during radiation therapy.

[0003] There are many different radiation therapy techniques that allow radiation to be applied from different angles, at different intensities, and over specific time periods. Before radiation therapy treatment, a treatment plan is created to determine how and where radiation should be applied. Typically, such plans are created with the aid of medical imaging techniques. For example, a computed tomography (CT) scan can be performed on the patient to produce a three-dimensional image of the area to be treated. This three-dimensional image allows the treatment planner to observe and analyze the target area and identify surrounding tissues. Furthermore, three-dimensional images can be recorded over a period of time (such as a respiratory cycle) to provide four-dimensional (4D CT) video that can inform the treatment plan.

[0004] Known imaging systems include CT imaging systems and cone beam computed tomography (CBCT) imaging systems. Compared to CBCT imaging systems, CT imaging systems have various advantages and disadvantages, and differ in terms of quality, physical size, measurement time, and cost.

[0005] Providing such systems as part of a radiotherapy device involves many challenges, including complexity and cost. Summary of the Invention

[0006] The invention is described in the independent claims. Optional features are described in the dependent claims. Attached Figure Description

[0007] Embodiments will now be described by way of example with reference to the accompanying drawings, in which:

[0008] Figure 1 This illustrates a known type of radiotherapy device or apparatus;

[0009] Figure 2aA cross-sectional view of a known type of radiotherapy device or apparatus with an imaging system is shown;

[0010] Figure 2b A cross-sectional view of a known type of radiotherapy device or apparatus with an imaging system is shown;

[0011] Figure 3a A cross-sectional view of the geometry of an imaging system according to this disclosure is shown;

[0012] Figure 3b A cross-sectional view of the geometry of an imaging system according to this disclosure is shown;

[0013] Figure 4 Cross-sectional and partial sectional views of the imaging system according to this disclosure coupled to the rack are shown;

[0014] Figure 5 The steps performed in a radiotherapy imaging method according to this disclosure are shown. Detailed Implementation

[0015] Overview

[0016] In general, this disclosure relates to an imaging system for a radiotherapy apparatus that can provide both CT imaging capabilities and CBCT imaging capabilities. The imaging system includes a single imaging radiation source, a CT detector, and a CBCT detector. The CT detector and the CBCT detector are different types of detectors with different characteristics. Embodiments are disclosed in which alternating CT imaging capabilities and CBCT imaging capabilities can be provided using a single common imaging radiation source.

[0017] As used herein, CT imaging systems differ from CBCT imaging systems. These terms are used to refer to different imaging modalities and different associated imaging devices. CT imaging involves rotating an imaging radiation source 360° around the patient at axially spaced locations, directing a fan-shaped beam toward a relatively narrow panel to acquire data that can be used to generate 2D cross-sectional images of the patient. The imaging radiation source or patient can then be gradually advanced to acquire another 2D image and thereby establish a 3D image of the patient or region of interest through multiple 360° rotations around the patient. Alternatively, in addition to gradual advancement, the patient or radiation source can be advanced slowly and continuously while the radiation source rotates to acquire the necessary data to construct a 3D CT image via a helical or spiral delivery of imaging radiation. In “true” or “conventional” CT imagers, imaging radiation is typically emitted in a thin “fan” that projects a slender shape that is much narrower in one direction than in the other onto the detector. Thus, a narrow, curved detector is used.

[0018] In contrast, CBCT imaging systems use a wider cone beam and a larger panel to cover most of the patient with a single full, half, or other angle of rotation around the patient, thereby acquiring multiple 2D projections of the object from various angles for reconstructing 3D images. CBCT systems are therefore able to deliver 3D images quickly and have fewer gantry rotations compared to conventional CT systems. For example, it is possible to achieve a 3D imaging volume using a CBCT modality via a single 180-degree rotation around the patient.

[0019] CT detectors are typically very expensive per unit area, so surface area is minimized by using a curved detector that translates around the patient. The curvature follows the geometry and angular span of the fan-shaped beam and can have a relatively narrow dimension transverse to the beam plane, i.e., a dimension comparable to the thickness of the fan-shaped beam. CBCT images are obtained using a typically less expensive two-dimensional flat-panel detector, which is insufficient for high-quality CT imaging due to several technical differences and drawbacks. CBCT images are generally acquired faster than CT images and are often used for intra-fractional imaging. Partly due to these advantages in cost and speed, CBCT imaging systems have been considered for use in radiation therapy equipment, for example, to provide 3D images that can guide or form the basis of radiation therapy.

[0020] However, CBCT images are generally of lower quality and, unlike images produced by helical delivery CT imaging, contain inherent artifacts that must be considered. These drawbacks can compromise the quality of the 3D images obtained by a CBCT system. Other advantages can be achieved by using thinner slices with helical imaging in CT, such as reduced scattering of the panel and, as mentioned above, fewer artifacts generated during reconstruction—overall, higher image quality and lower patient doses can be obtained with CT imaging. However, radiotherapy equipment that includes “true” or “conventional” CT imaging systems capable of providing higher quality images than CBCT is difficult to develop due to the cost and complexity of such systems. Even when attempting to integrate CT imaging systems into radiotherapy equipment, it is desirable to include CBCT-type imaging techniques based on two-dimensional panels, particularly for intrafractional imaging. However, producing such large-area panels with the additional quality required for CT imaging capabilities is extremely expensive.

[0021] Therefore, this document discloses an imaging system that can be integrated with radiotherapy equipment to provide multiple types of imaging. This disclosure enables the integration of CT and CBCT imaging into radiotherapy equipment without significantly increasing cost or complexity and with minimal changes in equipment size.

[0022] Although this disclosure describes various examples and embodiments related to CBCT imaging, it should be understood that the systems, devices, and methods disclosed herein can actually be used to perform other types of cross-sectional imaging, including 2D and 3D imaging. Therefore, devices described as suitable for CBCT (such as detectors) should be interpreted as suitable for desired cone-beam imaging techniques; that is, the detector need not be able to produce a full 3D sample, but can be designed to produce 2D CBCT-type images. Similarly, variations of 3D and 4D CT imaging exist, and the use of the term “CT” should not be construed as limited to a particular variation of a 2D slice or helical configuration. This disclosure is intended to relate to a higher quality form of pre-treatment imaging, referred to as “CT,” and a lower quality but faster form of intrafraction imaging, referred to as “CBCT.” Similarly, for illustrative purposes, a “flat panel” detector is disclosed, and in some examples, this detector may be a curved detector suitable for two-dimensional detection.

[0023] Detailed description

[0024] Figure 1 A radiotherapy (RT) device 100 is shown. This device and its components are well known to those skilled in the art, but are described in general herein to provide useful additional information to this disclosure.

[0025] Figure 1 The RT device 100 shown includes a radio frequency wave source 102, an RF transmission device 103, an accelerating waveguide 104, an electron source 106, a treatment head including a collimator 108 (such as a multi-leaf collimator for shaping the treatment beam 110), a housing 112 (shown in partial cross-section), and a patient support surface 114. The depicted device does not have the typical housing that covers the entire RT device in commercial environments such as hospitals. In use, the device also includes a housing that defines an aperture together with a ring gantry. The patient support surface 114 is movable and can be used to support the patient at the start of radiotherapy and to move them or another object into the aperture.

[0026] The RT device beam generation system includes a radio frequency wave source 102, an accelerating waveguide 104, and an electron source 106. The beam generation system is configured to generate a radiation beam (also referred to as a therapeutic beam 110), which is collimated and shaped by a collimator 108 and guided by a guide aperture. The beam generation system is based on a linear accelerator (linac) design.

[0027] A radio frequency (RF) source 102 (such as a magnetron) is configured to generate RF waves. The RF source 102 is coupled to an accelerating waveguide 104 via an RF transmission device 103, which may include a circulator and is configured to pulse the RF waves into the accelerating waveguide 104. The RF waves can travel from the RF source 102 through an RF input window and into an RF input connection conduit or tube. An electron source 106 (such as a diode or transistor electron gun) is also coupled to the accelerating waveguide 104 and configured to inject electrons into the waveguide 104. The electron injection into the accelerating waveguide 104 is synchronized with the RF wave pumping into the accelerating waveguide 104. The design and operation of the RF source 102, the electron source 106, and the accelerating waveguide 104 are such that the RF waves accelerate the electrons to very high energies as they propagate through the accelerating waveguide 104.

[0028] The design of the accelerating waveguide 104 depends on whether it uses standing waves or traveling waves to accelerate electrons, although the waveguide typically comprises a series of units, each connected by apertures or "apertures" through which the electron beam can pass. These units are coupled to generate a suitable electric field mode that accelerates electrons propagating through the accelerating waveguide 104. As electrons are accelerated within the accelerating waveguide 104, the electron beam path can be controlled by a suitable arrangement of guide magnets or guide coils surrounding the accelerating waveguide 104. The arrangement of the guide magnets may include, for example, two sets of quadrupole magnets.

[0029] Once the electrons are accelerated, they enter the flight tube. The flight tube is connected to the waveguide via a connecting tube. This connecting tube or connection structure can be called a drift tube. The electrons travel toward a heavy metal target, which may include, for example, tungsten. As the electrons pass through the flight tube, an arrangement of focusing magnets guides and focuses the electron beam onto the target.

[0030] To ensure unimpeded electron propagation as the electron beam travels toward the target, a vacuum system, including a vacuum pump or a vacuum pump array, is used to evacuate the accelerating waveguide 104. The pump system generates ultra-high vacuum (UHV) conditions within the accelerating waveguide 104. The vacuum system also ensures UHV conditions in the electron source 106, as well as in the drift tube and flight tube (if used). Electrons can be accelerated to near the speed of light within the vacuum waveguide.

[0031] The beam generation system is configured to direct a therapeutic beam 110 to a patient positioned on a patient support surface 114. The therapeutic beam 110 includes therapeutic radiation. The beam generation system may include a heavy metal target to which high-energy electrons leaving the waveguide are directed. When the electrons strike the target, X-rays are generated in various directions. A primary collimator can block X-rays traveling in certain directions and allow only forward-traveling X-rays to pass through, thereby generating the therapeutic beam 110. The X-rays may be filtered and may pass through one or more ion chambers for dose measurement. As part of radiotherapy, the beam may be shaped in various ways (e.g., by using collimator 108) before entering the patient's body using a beamforming device.

[0032] In some implementations, the beam generation system is configured to emit either an X-ray beam or an electron particle beam. Such implementations allow the device to provide electron beam therapy, an external beam therapy in which electrons, rather than X-rays, are directed to the target area. By adjusting components of the beam generation system, a first mode of emitting X-rays and a second mode of emitting electrons can be “switched” between them. Essentially, switching between the first and second modes is achieved by moving a heavy metal target into or out of the electron beam path and replacing it with a so-called “electron window.” The electron window is substantially transparent to the electrons and allows them to exit the flight tube.

[0033] Typically, the radiation detector is diametrically opposed to the collimator 108. The radiation detector is adapted and configured to generate radiation intensity data. In particular, the radiation detector is positioned and configured to detect the intensity of radiation that has passed through the object. The radiation detector may form part of an entrance imaging system.

[0034] The beam generation system is attached to a rotatable gantry 116 so that it rotates together with the gantry 116. In this way, the beam generation system can rotate around the patient, allowing the treatment beam 110 to be applied from different angles around the gantry 116. In a preferred implementation, the gantry is continuously rotatable. In other words, the gantry can rotate 360 ​​degrees around the patient, and in fact, can continue to rotate beyond 360 degrees. The gantry can be annular, i.e., a ring-shaped gantry.

[0035] Figure 1 The RT device 100 can be controlled by a controller (not shown). The controller is a computer, processor, or other processing device. The controller may consist of several discrete processors; for example, an RT device processor that controls the operation of the RT device; and a patient support surface processor that controls the operation and actuation of the patient support surface 114. The controller is communicatively coupled to a memory, such as a computer-readable medium.

[0036] Figure 2a and Figure 2b It shows that it can be Figure 1 The radiotherapy device 100 and radiotherapy device 220 may have possible geometric arrangements, and the radiotherapy device 220 also includes an imaging system of a known type. The imaging system includes an imaging radiation source 206 (such as an X-ray radiation source) and an imaging detector 205. Figure 2a and Figure 2b The device 220 depicted is configured to provide radiotherapy in a coplanar arrangement. An imaging system and a therapeutic radiation source 200 are coupled to a gantry 204, which may be a ring-shaped gantry. The therapeutic radiation source 200 is configured to emit radiation toward a radiation detector 202 along a therapeutic radiation axis 207, and an imaging radiation source 206 is configured to emit radiation along an imaging beam axis 208.

[0037] The therapeutic radiation source 200 can rotate around the patient 209 positioned in the treatment space of the device 220. Regardless of the rotation angle of the gantry, the point in space through which the therapeutic radiation axis 207 passes is the radiation isocenter 213. In other words, regardless of the rotation angle of the radiation head 200 around the gantry 204, radiation can be delivered to the radiation isocenter 213 at the center of the gantry 204. The rotation axis of the gantry 204 can also pass through the radiation isocenter 213 in a direction perpendicular to both the therapeutic radiation axis 207 and the imaging radiation axis 208. Figure 2a and Figure 2b In the coplanar arrangement shown, radiation is emitted in a plane perpendicular to the rotation axis of the radiation source 200.

[0038] Device 220 may include a movable patient table 210 configured to move a patient 213 into and out of an aperture in gantry 204. The patient table 210 may be moved by a suitable arrangement or configuration of motors and actuators. To provide an image of the patient 213, the patient table 213 is actuated to move the patient into the aperture in the gantry. While at least a portion of the patient 213 is within the aperture, the imaging system rotates around the patient while the imaging radiation source 206 emits a radiation beam. Radiation intensity data, indicating the degree to which the imaging radiation is attenuated by the patient 213, is collected by detector 205.

[0039] When radiation is delivered to a patient, for example, according to a treatment plan, the gantry 204 rotates, causing the radiation detector 202 and the treatment radiation source 200 to rotate together around the circular support track 206, such that they are always arranged 180 degrees to each other around the gantry 204. The treatment radiation source 200 thus directs radiation to the patient 209 from various angles surrounding the patient 209. Figure 2a In the rack 204, the therapeutic radiation source 200 is located at the top of the rack 204, and the radiation detector 202 is located at the bottom of the rack 204. Figure 2b The diagram shows that the two components have been rotated 180 degrees around the frame's axis of rotation, which enters the plane of the figure.

[0040] Components of the imaging system and radiotherapy system can be rigidly coupled to the gantry 204 so that a fixed angle, which can be 90 degrees or other values, is maintained between each component as the gantry 204 rotates. Figure 2a In the configuration, the imaging radiation source 206 is located on the right side of the rack 204, and the imaging radiation detector 205 is located on the left side of the rack 204. Figure 2b This shows that both components have rotated 180 degrees around the gantry rotation axis. The angle between the therapeutic radiation beam axis and the imaging radiation axis is constant and independent of the gantry rotation.

[0041] Figure 2a and Figure 2b The geometry can be used alternately for CT imaging or CBCT imaging. For CT imaging, a suitable CT imaging detector and CT source for imaging radiation are used. Figure 2a and Figure 2b A fan-shaped imaging radiation beam, as illustrated, is used for CT imaging. In this case, the imaging radiation source 206 is configured to emit a fan-shaped beam that still has a central axis shown as a dashed line in the figure. For CBCT imaging, a corresponding CBCT imaging radiation detector and imaging radiation source are used. In this case, the imaging radiation source 206 is configured to emit a cone-shaped beam. The gantry can be rotated such that the imaging radiation source 206 and the imaging radiation detector 205 rotate around the patient according to the desired position and velocity requirements for producing the desired image. As the imaging system rotates and attenuation data is collected, data from different angles are collected, which allows for the reconstruction of cross-sectional images using known techniques. The imaging system may also include a processor or controller configured to receive signals from each of the detectors and generate or reconstruct images based on those signals.

[0042] Figure 3 shows the... Figure 2a and Figure 2b An example imaging system with improved layout is provided to combine CT and CBCT imaging capabilities into a single system, rather than being constrained to a specific type of imaging due to cost and complexity limitations. The system is shown in front view 300 and side view 320 corresponding to the views in Figure 2. The imaging radiation source 301 is mounted to a rotatable annular gantry 303, such as… Figure 1 The gantry of the radiation therapy equipment. Patients or subjects to be subjected to imaging or radiation therapy can be placed in the aperture defined by the gantry 303.

[0043] Two detectors are mounted to a ring gantry 303, located on opposite sides of the imaging radiation source 301. The first curved detector 305 possesses properties and quality suitable for CT imaging. For example, the curved detector could be a solid-state detector comprising a scintillator and / or a photodetector. The curved detector 305 is curved, with its axis of curvature aligned with the axis of curvature of the gantry, although the degree of curvature may differ. The curved detector 305 has an elongated face that covers a length equivalent to the patient's lateral body width in the direction in which a cross-sectional image is to be obtained (in one example, a standard length of 80 cm is used). To provide measurements suitable for CT imaging, the width of the face of the curved detector 305 is not extended further than necessary, reducing the required total detector surface area. This system enables CT imaging while utilizing existing radiotherapy gantry structures that can rotate, for example, at 20 rpm or even faster, without requiring modifications to the gantry structure or drive technology, resulting in very high cost efficiency.

[0044] The second flat panel detector 307 offers quality suitable for CBCT and is generally ideal for high-resolution 2D imaging, but it has lower sensitivity, dynamic range, and slower readout frequency, resulting in lower image quality and lower cost compared to the curved detector 305. For example, the flat panel detector 307 could be an amorphous silicon-based detector. The shape of the flat panel detector 307 differs from that of the curved detector 305, and it is a planar / non-curved panel with a width and length more similar in size, and less elongated than the curved detector 305, effectively producing a square detector.

[0045] The imaging radiation source 301 is configured to emit radiation in a direction parallel to the imaging axis 309 in the panel direction. The imaging axis 309 intersects perpendicularly with a second axis, which is the radiation therapy axis 311, as shown below. Figure 1 and Figure 2a and Figure 2bThe radiation therapy apparatus shown defines the direction of the therapeutic radiation. The two axes intersect at isocenter 313. In the side perspective view 320, the imaging radiation source 301 is shown positioned radially opposite to the flat panel detector 307 along the imaging axis 309. Therefore, the flat panel detector 307 is aligned with the isocenter 313. The flat panel detector 307 includes a flat panel of sufficient size for 2D imaging (such as 20×20cm, 25×25cm, 40×40cm, or any other suitable size) and has the same rotation angle as the curved detector 305. In this configuration, with the imaging radiation source 301 in the first position, both the imaging radiation source 301 and the flat panel detector 307 can rotate around the patient to provide CBCT imaging. The imaging radiation from the imaging radiation source 301 is emitted along the imaging axis 309 and, in the illustrated configuration, is incident on the second detector 307, not the curved detector 305. The bending detector 305 is positioned slightly outside the isocenter 313 in the longitudinal direction, although it has the same rotation angle as the isocenter 313. As shown in FIG3, the bending detector 305 is placed adjacent to the flat panel detector 307 and therefore adjacent to the imaging axis 309. This position can be a distance from the imaging axis 309 passing through the isocenter 313 equivalent to 32 rows, 64 rows or more. Those skilled in the art will understand that a line is equivalent to a pixel, such as a pixel 1 mm wide.

[0046] The size of the detectors is such that their placement side-by-side or adjacent to each other advantageously does not extend the length of the orifice of the radiotherapy equipment, which is determined by the other parts and components of the gantry. Therefore, corresponding detection capabilities suitable for CT imaging using the curved detector 305 and CBCT imaging using the flat panel detector 307 can be achieved without excessively increasing the size or footprint of the radiotherapy equipment.

[0047] In the example, the bending detector 305 measures 800mm × 64mm, although any suitable size can be used.

[0048] The imaging radiation source can be configured to be adjustable such that, in a first configuration, it is configured to emit imaging radiation toward a CT detector, and in a second configuration, it is configured to emit imaging radiation toward a CBCT panel detector. Such an imaging radiation source can be any imaging radiation source described with respect to the imaging system disclosed herein. The imaging radiation source 301 is configured such that it can alternately irradiate a flat panel detector 307 (as shown in Figure 3) and a curved detector 305. In one example, the imaging radiation source 301 is movable, or translational, using a motor, such that it can move laterally and be directed to emit along a second imaging axis 315 instead of along the previous imaging axis 309. Arrow AB in Figure 3 indicates possible linear directions of movement of the imaging radiation source 301. In another example, the imaging radiation source 301 can be rotated or tilted at an angle to point at and irradiate the curved detector 305, such that the curved detector 305 is irradiated with imaging radiation in the tilted position instead of the flat panel detector 307. In such cases, the curved detector 305 can be placed at an angle so that the illumination axis remains orthogonal; however, it does not need to be placed in this way and can actually be placed such that the illumination axis is not orthogonal to the detector surface. Of course, the default position can be reversed, so that the imaging radiation source 301 must be tilted toward the flat panel 307, which can then be mounted again in a corresponding angled or tilted position. In each example, the object or patient to be imaged is placed between the imaging radiation source 301 and the corresponding detector, and the imaging radiation source 301 and the corresponding detector rotate around the object according to the requirements of CT imaging technology (using the curved detector 305) or CBCT imaging technology (using the flat panel detector 307).

[0049] The reference isocenter 313 is precisely calibrated to the imaging coordinate system of the corresponding CBCT and CT images. Therefore, the acquired images and reconstructed 3D volumes can be correlated with the isocenter 313, making it possible to calculate and compensate for patient offset.

[0050] In some examples, the imaging radiation source 301 is configured to be movable, allowing the use of two alternative collimators. Alternatively, a single adjustable collimator is used. The purpose of each collimator component is to properly shape the beam for the corresponding CT or CBCT technique, i.e., using a curved detector 305 to generate a fan-shaped beam of imaging radiation for CT, and using a flat-panel detector 307 to generate a cone-shaped beam of imaging radiation for CBCT. In one example, instead of moving the imaging radiation source 301 laterally or at an angle, the imaging radiation source 301 emits a sufficiently wide cone or fan-shaped beam such that both detector panels are illuminated by it. In such examples, collimation can be selectively applied so that the cone-shaped beam is incident on the second detector 307 for CBCT and the fan-shaped beam is incident on the first detector 305 for CT. Such methods rely on sufficient flux density provided by the wider beam so that each detector receives a sufficient signal.

[0051] In some examples, the imaging radiation source 301 is an X-ray tube and generator suitable for CT imaging, although other forms of imaging radiation can be used. Using the same source for both types of imaging advantageously allows both types of imaging to be integrated into the radiotherapy system without undue cost and complexity. CT imaging can be used for pre-treatment imaging, and CBCT or 2D imaging can be used for intra-fractional imaging. When using the X-ray tube and generator, the generator is configured such that the imaging radiation source 301 can operate in a pulsed or continuous manner. In pulsed or continuous operation, the source can irradiate one panel at a time or two panels simultaneously, depending on the arrangement and method selected from those disclosed herein. The source can operate at typical energies between 50 kV and 150 kV, but can also operate outside this range or at more than one energy level.

[0052] In some examples, the imaging radiation source 301 is selected and positioned such that its field of view is almost not projected onto the entire flat panel surface of the flat panel detector 305; in other words, the flat panel detector 305 substantially fills the field of view of the imaging source. The control system of the imaging radiation source 301 is configured such that the source can be operated in a pulsed manner and / or in a manner suitable for fluorescence permeation, having a continuous imaging radiation beam.

[0053] Figure 4 Cross section 400 and partial section 420 of the system using the geometry of Figure 3 are shown. The imaging radiation source 301 is illustrated in each figure as existing in two alternating locations; however, this is for illustrative purposes only. As described above, only one imaging radiation source is used and... Figure 4In the system, the imaging radiation source 301 can be moved from a first position 301a, where it passes through a first collimator 401, which generates a cone-shaped beam 403 and is guided to a flat panel detector suitable for CBCT, equivalent to the flat panel detector 307 of FIG. 3. In a second position 301b, the imaging radiation source 301 passes through a second collimator 405, which generates a fan-shaped beam 407 and is guided to a CT detector, equivalent to the curved detector 305 of FIG. 3. Alternatively, an adjustable single collimator component can be used to generate either a fan-shaped or cone-shaped beam. In each example, the fan-shaped beam has a cross-section much narrower in one dimension than in the other, and the cone-shaped beam has cross-sections in two similar dimensions and can be approximately circular or square. As in the system of FIG. 3, these components are mounted on a rotatable gantry 410. Similar to the system of FIG. 3, Figure 4 The system can be with Figure 1 Used together with radiotherapy equipment 100. Figure 4 The differences in shape and projection shape between the narrow fan-shaped beam 407 and the wider conical beam 403 are shown.

[0054] Figure 5 This is a flowchart depicting method 500 according to this disclosure. Method 500 can be described using Figure 3 or... Figure 4 The system described herein is used to perform this. Method 500 is an example of improved imaging options allowed by the system of this disclosure.

[0055] In general, method 500 can be used to update an existing treatment plan during scheduled delivery, i.e., during radiotherapy treatment. Images taken by an imaging system at a specific gantry rotation angle and along a specific "line of sight" can be used to inform radiation delivery along the same line of sight.

[0056] In the example, an existing treatment plan can consist of a set of several radiation delivery variables defined for each of multiple gantry rotation angles. Clinically equivalent CT images can be acquired and 3D tomographic volumes reconstructed. Therefore, the original plan can be reviewed against the patient's actual anatomy, and if necessary, it can be updated or modified so that the delivery plan and dose will accurately hit the target from all angles. Alternatively, the patient's position can be adjusted in 3D or 6D based on the CT images. Such pre-treatment imaging can be performed using the system's CT imaging capabilities.

[0057] At step 510, an image is acquired using a first detector panel. In this implementation, the imaging system is a CT imaging system and the image is a CT image. The first detector panel is suitable for CT imaging, such as the bending detector 305 of Figure 3.

[0058] As described above, the imaging radiation source can be moved laterally or rotated, or generate a sufficiently wide beam to illuminate two adjacent detectors. In step 510, the imaging radiation source is positioned such that it illuminates the first detector panel.

[0059] At step 520, one or more radiation delivery variables are updated based on the acquired image. This can be done in any suitable manner for a skilled reader. For example, the radiation delivery variables may include one or more beam weights. The radiation delivery variables may also include beam collimation variables, which may relate to the shape and size of the beam. Beam collimation variables may include, for example, the position of one or more blades of a multi-leaf collimator (MLC), the position of a beam stopper or beam aperture, and / or the tilt or position of the beam stopper and / or the MLC. The radiation delivery variables may also include the duration of radiation delivery. The radiation delivery variables may also include a gating variable that determines whether the beam is gated, i.e., stopped.

[0060] In the example, the CT images show that the target area has changed position relative to the image used as the basis for forming the original treatment plan. This could be because the patient has adjusted their position on the support surface. Radiation delivery variables can be updated to accommodate this change. For example, the MLC blade position can be adjusted systematically or individually to achieve the desired dose distribution, the patient positioning system can be adjusted in 3D or 6D, or the treatment plan can be updated—all to achieve target coverage and conserve healthy tissue. Updates can be performed using known optimization techniques known to the technician.

[0061] At step 530, the gantry is rotated such that when the image is acquired at point 520, the axis of the therapeutic radiation beam is aligned with the axis of the imaging beam. In other words, the image is acquired at a first moment along the first axis. The gantry is rotated by the necessary angle until, at a second moment, the radiation beam axis is aligned with the first axis, allowing the therapeutic radiation source to deliver radiation along the first axis.

[0062] At step 540, radiation is delivered according to the updated radiation delivery variables. The imaging radiation source is adjusted to illuminate the second detector panel by changing its angle or tilt, moving it laterally, or adjusting the collimator. The second detector panel is suitable for 2D or CBCT imaging, such as the flat panel 307 in Figure 3, and is used to perform intra-segment imaging. Typically, the CBCT panel and coordinate system are aligned with the radiation isocenter so that 2D images can be acquired during the radiation sequence with the patient in the same position, even if the pulses are staggered for optimal image quality.

[0063] Computer-based systems can be used to control or operate various parts of the systems, devices, methods, and apparatuses disclosed herein. Computer-based systems can be implemented in software, firmware, and / or hardware and may include a computer-readable medium containing instructions that, when executed by a processor, cause the system to perform any of the methods described herein.

[0064] It should be understood that the above description is intended to be illustrative and not restrictive. Many other implementations will become apparent to those skilled in the art upon reading and understanding the above description. Although this disclosure has been described with reference to specific example implementations, it will be appreciated that this disclosure is not limited to the described implementations but can be implemented through modifications and variations within the spirit and scope of the appended claims. Therefore, the specification and drawings should be considered illustrative and not restrictive. Consequently, the scope of this disclosure should be determined by reference to the appended claims and their equivalents.

Claims

1. An imaging system for a radiation therapy device, configured to deliver therapeutic radiation to a patient via a therapeutic radiation source. The imaging system includes an imaging radiation source, a CBCT panel detector, and a CT detector; in: The imaging radiation source is configured to be adjustable such that, in a first configuration, the imaging radiation source is configured to emit imaging radiation toward the CT detector, and in a second configuration, the imaging radiation source is configured to emit imaging radiation toward the CBCT detector. In the second configuration, the imaging radiation source is configured to emit imaging radiation along a first imaging axis; and The CT detector is positioned adjacent to the first imaging axis.

2. The system according to claim 1, wherein, The imaging radiation source is configured to move between a first position and a second position, wherein the first position corresponds to the first configuration and the second position corresponds to the second configuration.

3. The system according to claim 2, wherein, The imaging radiation source is configured to move between the first position and the second position via a translation mechanism.

4. The system according to claim 2, wherein, The imaging radiation source is configured to move between the first position and the second position via a rotation mechanism.

5. The system of claim 1, further comprising a collimator component arranged such that when the imaging radiation source is in the first configuration, the collimator component is configured to shape the radiation into a fan-shaped beam, and when the imaging radiation source is in the second configuration, the collimator component is configured to shape the radiation into a cone-shaped beam.

6. The system according to claim 1, wherein, The imaging radiation is X-ray radiation.

7. The system according to claim 1, wherein, The imaging radiation source is configured to operate in a pulsed manner.

8. The system according to claim 1, wherein, The CT detector measures 800 mm × 64 mm.

9. The system according to claim 1, wherein, The CBCT panel detector measures 250 mm × 250 mm.

10. A radiotherapy device comprising an imaging system, the radiotherapy device being configured to deliver therapeutic radiation to a patient via a therapeutic radiation source. The imaging system includes an imaging radiation source, a CBCT panel detector, and a CT detector; in: The imaging radiation source is configured to be adjustable such that, in a first configuration, the imaging radiation source is configured to emit imaging radiation toward the CT detector, and in a second configuration, the imaging radiation source is configured to emit imaging radiation toward the CBCT detector. In the second configuration, the imaging radiation source is configured to emit imaging radiation along a first imaging axis; and The CT detector is positioned adjacent to the first imaging axis.

11. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform an imaging method for radiation therapy, the method comprising: Prior to radiation therapy treatment, images are acquired using an imaging radiation source and CT detector panel in the first configuration; Update one or more radiation delivery variables based on the image; Configure radiation therapy equipment to deliver treatment based on updated radiation delivery variables; The imaging radiation source is adjusted to a second configuration, wherein the imaging radiation source is configured to emit imaging radiation along a first imaging axis, and the CT detector panel is positioned adjacent to the first imaging axis. A second image is acquired using the imaging radiation source and CBCT detector panel in the second configuration.

12. An imaging radiation source for use in CBCT panel detectors and CT detectors; in: The imaging radiation source is configured to be adjustable such that, in a first configuration, the imaging radiation source is configured to emit imaging radiation toward a CT detector, and in a second configuration, the imaging radiation source is configured to emit imaging radiation toward a CBCT panel detector. In the second configuration, the imaging radiation source is configured to emit imaging radiation along a first imaging axis; and The CT detector is positioned adjacent to the first imaging axis.

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