Systems and methods for X-ray imaging and targeted X-ray therapy

Abstract

A radiotherapy method using an X-ray apparatus includes positioning the cathode device of the X-ray source in imaging mode to focus electrons into a focal region of a first size on the anode. The X-ray source in imaging mode is activated to emit an X-ray beam toward the X-ray detector to obtain a first X-ray image of the target. The X-ray source or object is adjusted to align the target with its diagnostic image and direct the X-ray source toward the target, based on a comparison of the first X-ray image with the diagnostic image. The cathode device is switched to output mode to focus electrons into a second focal region having a second size larger than the first size on the anode. The X-ray source in output mode is activated to deliver a therapeutic dose of X-rays to the target.

Description

Technical Field

[0001] Aspects of the present disclosure are directed to X-ray imaging and X-ray therapy, and more particularly, to systems and methods for X-ray imaging and targeted X-ray therapy.

Background Art

[0002] Radiation therapy (RT) is generally considered an effective treatment option for locally controlling tumors. Many cancer patients incorporate RT as part of their overall cancer management plan. However, despite its ability to kill cancer cells, RT does not always result in a successful outcome. This is often due to the fact that the radiation dose required to eradicate a tumor can cause significant damage to surrounding healthy tissue both in the short term and the long term.

[0003] In recent years, there have been notable technological advancements in radiation therapy, particularly with regard to accurate tumor coverage and minimization of exposure to healthy tissue during treatment planning and delivery. As a result, cancer patients can now utilize proton beam radiation therapy and intensity-modulated radiation therapy (IMRT), as well as imaging-guided radiation therapy (IGRT).

[0004] State-of-the-art radiation therapy provides promising benefits to many cancer patients, but these benefits are often limited by the need for high doses of radiation that can cause unacceptable harm to critical structures near the tumor site. Additionally, current radiation therapy techniques may be less effective in pediatric patients, where developing normal tissues are often more sensitive to radiation than their tumors. Thus, pediatric patients generally cannot tolerate radiation therapy doses that can be curative for adults with the same disease.

[0005] An alternative treatment approach called spatially segmented radiotherapy (SFRT) has shown promise in improving the preservation of healthy tissue and has yielded promising results. Conventional radiotherapy typically uses broad, continuous beams of radiation to treat cancer. In contrast, SFRT uses specialized radiation characterized by unique spatial, temporal, and dose patterns. In SFRT, the radiation field is discrete and consists of beams ranging in width from tens of micrometers to several millimeters, or even several centimeters. The spacing between adjacent beams is typically several times (e.g., 2 to 10 times) the width of the beam itself.

[0006] Several SFRT techniques, including GRID, FLASH, LATTICE radiotherapy (LRT), and microbeam radiotherapy (MRT), are currently being studied in preclinical research, and some early clinical experience is available. The primary objective of these SFRT techniques is generally to achieve improved tumor control and reduce damage to healthy tissue. While common mechanisms may exist, our understanding of these mechanisms is currently limited. Bystander effects, abscopal effects, vascular damage, angiogenic responses, and immune responses have all been proposed as potential factors. Despite its potential as a cost-effective cancer treatment, SFRT has not yet been widely adopted in clinical practice, mainly due to the lack of effective radiation delivery systems.

[0007] Most SFRT treatments today are performed using conventional linear accelerators (LINACs). The dose rates of state-of-the-art LINAC machines are approximately 5 Gray / min (Gy / min). Recently, a specific form of SFRT treatment called Flash radiotherapy has been discovered to yield promising treatment outcomes. However, it requires relatively high dose rates (e.g., over 40 Gy / second) during treatment delivery. Dose rates of this magnitude cannot be achieved with existing LINACs. In addition, clinical LINACs generally generate X-rays in the megavolt (MV) range, which is unsuitable for SFRT treatment due to the large footprint of high-energy MV radiation resulting in an insufficient dose profile. Studies have shown that X-ray emission in the high kV range (e.g., several hundred kilovolts: 160kV–800kV) is preferable for SFRT treatment.

[0008] On the other hand, SFRT has been demonstrated using proton therapy and synchrotron-based systems. These advanced machines can deliver SFRT treatment with an acceptable dose profile at high dose rates. However, such machines are relatively expensive. The average cost of a proton therapy machine exceeds $50 million, and the average cost of a synchrotron facility exceeds $100 million. The high cost of such systems significantly hinders their clinical use.

[0009] In some cases, conventional X-ray sources are also being considered for SFRT therapy. For example, as shown in Figure 1, a conventional X-ray source includes an electron cathode and an X-ray anode. The anode carries a high voltage, for example, up to several hundred kV. Electrons emitted by the cathode are accelerated to high energy by the anode voltage and collide with a region (focal point) on the anode to produce X-ray emission. Some X-ray sources may have focusing electrodes to adjust / control the size of the focal point on the anode. However, conventional X-ray sources have relatively low dose rates. One reason for the relatively low dose rate is that such conventional X-ray sources are generally designed for imaging applications that require relatively small focal point sizes (e.g., diameters of less than a millimeter to several millimeters). Small focal points are preferable to provide high-resolution imaging (e.g., a small focal point size provides a higher number of pixels proportional to the desired resolution). However, small focal point sizes also limit the maximum output power (dose rate) of the X-ray source, for example, due to the thermal limitations of the small focal point. Many conventional X-ray sources can only operate at relatively low currents (e.g., in the mA range). Some high-power X-ray sources (e.g., using rotating anodes) are designed to operate at high peak power (e.g., up to 100 kW), but are generally limited to relatively short exposure times (e.g., tens of milliseconds) and low duty cycles (e.g., a few percent).

[0010] To deliver the necessary power (dose rate) for SFRT therapy, particularly flash radiotherapy, an X-ray source with a relatively large focal size or focal line (e.g., up to several tens of centimeters) is required. Some conventional X-ray sources have electron beam focusing / defocusing mechanisms (electrostatic or magnetic) to adjust the focal size on the anode, as shown in Figure 1, for example. However, the range of focal sizes and focal configurations achievable by such focusing / defocusing mechanisms are generally very limited (2-3 times the size range).

[0011] Furthermore, modern radiotherapy requires imaging guidance to accurately deliver the radiation dose to the tumor. In SFRT therapy, due to the small size of the radiation field (as small as tens of micrometers) and high dose rates (e.g., Flash radiotherapy requiring dose rates exceeding 40 Gy / second), performing imaging guidance during treatment becomes even more crucial. In some existing SFRT systems, imaging guidance is generally achieved by an additional, separate, independent imaging device, typically a separate X-ray imaging device combined with the radiotherapy device. The imaging device typically generates images from a different direction than the treatment beam emitted by the radiotherapy device, which is very often orthogonal to the treatment beam, and this is not ideal for imaging guidance and target tracking. Such a configuration also complicates the overall system design and increases system costs. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] Therefore, there is a need for an X-ray radiotherapy system that can accommodate and enable both radiotherapy and imaging functions while minimizing configuration changes between both operating modes. Such an X-ray radiotherapy system should include an X-ray source having a cathode device that can operate in an imaging mode capable of producing high-resolution images using a small focus on the anode, and in a therapy mode capable of achieving the high dose rates desirable for cancer treatment using a large focus / line on the anode. Such an X-ray radiotherapy system should also include imaging guidance and feedback functions before and / or during the radiotherapy phase to ensure that the dose(s) are delivered precisely to the correct target location so that minimal healthy tissue is subjected to radiotherapy. [Means for solving the problem]

[0013] The above and other needs are satisfied by the present disclosure, which in one aspect provides a method for providing multimodal X-ray therapy to a target in an object using an X-ray apparatus including an X-ray source and an X-ray detector, wherein the X-ray source includes an anode and a field emission cathode apparatus located spaced apart from the anode and positioned to emit electrons toward the anode, and the target is determined from a diagnostic image of the target obtained by diagnostic imaging of the object, and is a diagnostic image. Such a method includes: positioning the field emission cathode device of an X-ray source in imaging mode to focus electrons into a first focal region on the anode, the first focal region having a first focal region size; imaging the target by operating the X-ray source in imaging mode and emitting the imaging X-ray beam toward an X-ray detector so that the imaging X-ray beam interacts with the target to obtain a first X-ray image of the target; adjusting the X-ray source or object in response to a comparison between the first X-ray image and a diagnostic image of the target to align the target with the diagnostic image of the target and direct the X-ray source toward the target; switching the position of the field emission cathode device in output mode to focus electrons into a second focal region on the anode, the second focal region having a second focal region size larger than the first focal region size; and operating the X-ray source in output mode to emit a first therapeutic X-ray beam toward the target and deliver a first dose of X-rays to the target.

[0014] Another aspect of the present disclosure provides a multimodal X-ray system for providing X-ray therapy to a target within an object, the target being determined from a diagnostic image of the target obtained by diagnostic imaging of the object. Such an X-ray system comprises an X-ray detector, an X-ray source including an anode, a field emission cathode device spaced apart from the anode and positioned to emit electrons toward the anode, and a controller communicating with the X-ray source and the X-ray detector. The controller is configured to instruct the X-ray source to position the field emission cathode in imaging mode to focus electrons into a first focal region on the anode, and to image the target by operating the X-ray source in imaging mode and emitting an imaging X-ray beam such that the first focal region has a first focal region size and the imaging X-ray beam interacts with the target and is detected by the X-ray detector to obtain a first X-ray image of the target, and in response to a comparison between the first X-ray image and the diagnostic image of the target, adjust the X-ray source or the target to align the target with the diagnostic image of the target and direct the X-ray source toward the target, and instruct the X-ray source to switch the position of the field emission cathode in output mode to focus electrons into a second focal region on the anode, such that the second focal region has a second focal region size larger than the first focal region size, and operate the X-ray source in output mode to emit a first therapeutic X-ray beam toward the target and deliver a first dose of X-rays to the target.

[0015] A further aspect of the present disclosure provides a method for providing a plurality of modes of an X-ray source apparatus, the X-ray source apparatus comprising an anode and a field emission cathode apparatus located spaced apart from the anode and arranged to emit electrons toward the anode. Such a method includes arranging the field emission cathode apparatus in an imaging mode to focus electrons onto a first focal region on the anode, the first focal region having a first focal region size, and reversibly switching the arrangement of the field emission cathode apparatus to an output mode to focus electrons onto a second focal region on the anode, the second focal region having a second focal region size larger than the first focal region size.

[0016] A further aspect of the present disclosure provides a multimodal X-ray source apparatus comprising an anode and a field emission cathode apparatus located spaced apart from the anode and arranged to emit electrons toward the anode, wherein the field emission cathode apparatus is switchable between an imaging mode in which electrons are focused to a first focal region on the anode, the first focal region having a first focal region size, and an output mode in which electrons are focused to a second focal region on the anode, the second focal region having a second focal region size larger than the first focal region size.

[0017] Therefore, this disclosure includes, but is not limited to, the following exemplary embodiments.

[0018] Exemplary Embodiment 1: A method for providing multimodal X-ray therapy to a target in an object using an X-ray apparatus including an X-ray source and an X-ray detector, wherein the X-ray source includes an anode and a field emission cathode apparatus positioned spaced apart from the anode and configured to emit electrons toward the anode, the target is determined from a diagnostic image of the target obtained by diagnostic imaging of the object, and the method is to position the field emission cathode apparatus of the X-ray source in imaging mode to focus electrons into a first focal region on the anode, wherein the first focal region has a first focal region size, and to position the imaging X-ray beam so as to interact with the target to obtain a first X-ray image of the target. A method comprising: imaging a target by operating an X-ray source in a mode and emitting an imaging X-ray beam toward an X-ray detector; adjusting the X-ray source or object in response to a comparison between a first X-ray image and a diagnostic image of the target to align the target with the diagnostic image of the target and direct the X-ray source toward the target; switching the configuration of a field emission cathode device to output mode to focus electrons into a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size; and operating the X-ray source in output mode to emit a first therapeutic X-ray beam toward the target and deliver a first dose of X-rays to the target.

[0019] Exemplary Embodiment 2: A method by any of the preceding exemplary embodiments or a combination thereof, comprising: after delivering a first dose of X-rays to a target, switching the configuration of the field emission cathode device of the X-ray source to imaging mode; re-imaging the target using the X-ray device to obtain a second X-ray image of the target; adjusting the X-ray source or object in response to a comparison of the second X-ray image with the diagnostic image of the target to align the target with the diagnostic image of the target and direct the X-ray source toward the target; switching the configuration of the field emission cathode device to output mode to focus electrons to a second focal region on the anode; and operating the X-ray source in output mode to emit a second therapeutic X-ray beam toward the target and deliver a second dose of X-rays to the target.

[0020] Exemplary Embodiment 3: A method by any of the preceding exemplary embodiments or a combination thereof, comprising positioning an X-ray detector opposite the X-ray source when the field emission cathode device of the X-ray source is in transmission imaging mode.

[0021] Exemplary Embodiment 4: A method by any of the preceding exemplary embodiments or a combination thereof, comprising positioning an X-ray detector adjacent to an X-ray source when the field emission cathode apparatus of an X-ray source is in backscatter imaging mode.

[0022] Exemplary Embodiment 5: A method by any of the preceding exemplary embodiments or a combination thereof, comprising positioning an X-ray detector so as not to receive a first therapeutic X-ray beam or a second therapeutic X-ray beam when the field emission cathode apparatus of an X-ray source is in output mode.

[0023] Exemplary Embodiment 6: Adjusting the X-ray source or the object includes adjusting the distance between the X-ray source and the object, adjusting the angular position of the X-ray source within the orbit around the object, or adjusting the position of the X-ray source or the object relative to the other in the lateral direction and non-parallel to the imaging X-ray beam, according to any of the preceding exemplary embodiments or combinations thereof.

[0024] Exemplary Embodiment 7: The target margin is determined from diagnostic imaging, and the method includes collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted in the output mode by the X-ray source such that the lateral dimensions of the first therapeutic X-ray beam and the second therapeutic X-ray beam are each less than or equal to the lateral dimension of the target margin perpendicular to the first therapeutic X-ray beam and the second therapeutic X-ray beam, according to any of the preceding exemplary embodiments or combinations thereof.

[0025] Exemplary Embodiment 8: Collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam includes collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in the output mode using a slit collimator such that the first therapeutic X-ray beam or the second therapeutic X-ray beam is emitted as a linear region onto the target, according to any of the preceding exemplary embodiments or combinations thereof.

[0026] Exemplary Embodiment 9: Operating the X-ray source in the output mode to emit the first X-ray dose or the second X-ray dose to the target includes operating the X-ray source in the output mode to emit the first X-ray dose or the second X-ray dose to the target at a predetermined X-ray dose rate over a predetermined time to provide a cumulative X-ray dose to the target, according to any of the preceding exemplary embodiments or combinations thereof.

[0027] Exemplary Embodiment 10: The method according to any preceding exemplary embodiment or combinations thereof, including performing imaging and re-imaging of a target and delivering a first X-ray dose and a second X-ray dose using the same X-ray source.

[0028] Exemplary Embodiment 11: The method according to any preceding exemplary embodiment or combinations thereof, including collimating a first imaging X-ray beam or a second imaging X-ray beam emitted by an X-ray source in an imaging mode using a cone beam collimator such that the first imaging X-ray beam or the second imaging X-ray beam is emitted onto an object as an elliptical region or a circular region.

[0029] Exemplary Embodiment 12: The method according to any preceding exemplary embodiment or combinations thereof, including tracking the movement of an object during delivery of a first X-ray dose and adjusting the X-ray source or the object in response to the tracked movement of the object to align the target with a diagnostic image of the target and maintaining the X-ray source directed towards the target.

[0030] Exemplary Embodiment 13: A multimodal X-ray system for providing X-ray therapy to a target within an object, wherein the target is determined from a diagnostic image of the target obtained by diagnostic imaging of the object, and the X-ray system includes an X-ray source, an X-ray source comprising an X-ray detector, an anode, and a field emission cathode device spaced apart from the anode and positioned to emit electrons toward the anode, and a controller communicating with the X-ray source and the X-ray detector, instructing the X-ray source to position the field emission cathode device in imaging mode to focus electrons to a first focal region on the anode, the first focal region having a first focal region size, the imaging X-ray beam interacting with the target and detected by the X-ray detector to form a first X-ray image of the target A multimodal X-ray system comprising: a controller configured to image a target by operating an X-ray source in imaging mode and emitting an imaging X-ray beam to obtain an image; adjusting the X-ray source or object in response to a comparison of a first X-ray image with a target diagnostic image to align the target with the target diagnostic image, direct the X-ray source toward the target, instruct the X-ray source to switch the configuration of the field emission cathode device to output mode to focus electrons into a second focal region on the anode, the second focal region having a second focal region size larger than the first focal region size, and operating the X-ray source in output mode to emit a first therapeutic X-ray beam toward the target and deliver a first dose of X-rays to the target.

[0031] Exemplary Embodiment 14: A system according to any of the preceding exemplary embodiments or combinations thereof, wherein the controller is configured to instruct the X-ray source to switch the field emission cathode configuration to imaging mode after a first dose of X-rays has been delivered to the target, to re-image the target using the X-ray apparatus to obtain a second X-ray image of the target, to adjust the X-ray source or object in response to a comparison of the second X-ray image with the diagnostic image of the target to align the target with the diagnostic image of the target, to direct the X-ray source toward the target, to switch the field emission cathode configuration to output mode to instruct the X-ray source to focus electrons to a second focal region on the anode, and to operate the X-ray source in output mode to emit a second therapeutic X-ray beam toward the target and deliver a second dose of X-rays to the target.

[0032] Exemplary Embodiment 15: A system according to any of the preceding exemplary embodiments or a combination thereof, wherein the X-ray detector is positioned opposite the X-ray source when the field emission cathode apparatus of the X-ray source is in transmission imaging mode.

[0033] Exemplary Embodiment 16: A system according to any of the preceding exemplary embodiments or a combination thereof, wherein the X-ray detector is positioned adjacent to the X-ray source when the field emission cathode apparatus of the X-ray source is in backscatter imaging mode.

[0034] Exemplary Embodiment 17: A system according to any of the preceding exemplary embodiments or a combination thereof, wherein the X-ray detector is positioned not to receive the first therapeutic X-ray beam or the second therapeutic X-ray beam when the field emission cathode apparatus of the X-ray source is in output mode.

[0035] Exemplary Embodiment 18: A system according to any of the preceding exemplary embodiments or combinations thereof, wherein the controller is configured to adjust the X-ray source or the object by adjusting the distance between the X-ray source and the object, adjusting the angular position of the X-ray source in a trajectory around the object, or adjusting the position of the X-ray source or the object relative to the other in the lateral direction and non-parallel to the imaging X-ray beam.

[0036] Exemplary Embodiment 19: A system according to any of the preceding exemplary embodiments or combinations thereof, wherein the target margin is determined from a diagnostic image, and the system comprises a collimator positioned between the X-ray source and the object, the collimator being configured to collimate the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in output mode such that the lateral dimensions of each first therapeutic X-ray beam and the second therapeutic X-ray beam are less than or equal to the lateral dimension of the target margin perpendicular to each first therapeutic X-ray beam and the second therapeutic X-ray beam.

[0037] Exemplary Embodiment 20: A system according to any of the preceding exemplary embodiments or a combination thereof, comprising a slit-beam collimator configured to collimate a first therapeutic X-ray beam or a second therapeutic X-ray beam emitted in output mode by an X-ray source such that the first therapeutic X-ray beam or the second therapeutic X-ray beam is emitted onto a target as a linear region.

[0038] Exemplary Embodiment 21: A system according to any of the preceding exemplary embodiments or combinations thereof, wherein the controller is configured to operate an X-ray source in output mode to emit a first or second X-ray dose to a target at a predetermined X-ray dose rate over a predetermined time, thereby providing a cumulative X-ray dose to the target.

[0039] Exemplary Embodiment 22: A system according to any of the preceding exemplary embodiments or a combination thereof, wherein imaging and re-imaging of a target and delivery of a first and second X-ray dose are performed using the same X-ray source.

[0040] Exemplary Embodiment 23: A system according to any of the preceding exemplary embodiments or combinations thereof, comprising a cone-beam collimator positioned between an X-ray source and an object, configured to collimate the first imaging X-ray beam or the second imaging X-ray beam emitted by the X-ray source in imaging mode such that the first imaging X-ray beam or the second imaging X-ray beam is emitted onto the object as an elliptical or circular region.

[0041] Exemplary Embodiment 24: A system according to any of the preceding exemplary embodiments or a combination thereof, comprising a tracking device configured to communicate with a controller and track the movement of an object during the delivery of a first dose of X-rays, wherein the controller is configured to adjust the X-ray source or the object in response to the tracked movement of the object to align the target with the diagnostic image of the target and to keep the X-ray source oriented toward the target.

[0042] Exemplary Embodiment 25: A method for providing multiple modes of an X-ray source apparatus, the X-ray source apparatus comprising an anode and a field emission cathode apparatus located spaced apart from the anode and arranged to emit electrons toward the anode, the method comprising: arranging the field emission cathode apparatus in an imaging mode to focus electrons onto a first focal region on the anode, wherein the first focal region has a first focal region size; and reversibly switching the arrangement of the field emission cathode apparatus to an output mode to focus electrons onto a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size.

[0043] Exemplary Embodiment 26: A method by any of the preceding exemplary embodiments or a combination thereof, wherein the field emission cathode apparatus comprises a plurality of individually controllable field emission cathodes, and arranging the field emission cathode apparatus in imaging mode includes activating a first amount of field emission cathodes to direct the electrons thereby emitted to a first focal region on the anode.

[0044] Exemplary Embodiment 27: A method by any of the preceding exemplary embodiments or a combination thereof, wherein the field emission cathode apparatus comprises a plurality of individually controllable field emission cathodes, and switching the arrangement of the field emission cathode apparatus to output mode involves activating a second amount of field emission cathodes, wherein the second amount is greater than the first amount, in order to direct the electrons emitted thereby to a second focal region.

[0045] Exemplary Embodiment 28: A method according to any of the preceding exemplary embodiments or a combination thereof, wherein directing electrons to a second focal region involves directing electrons from each of a second quantity of field emission cathodes to their respective corresponding focal regions on the anode, the respective corresponding focal regions being adjacent to each other on the anode and arranged to form a second focal region on the anode.

[0046] Exemplary Embodiment 29: A method by any of the preceding exemplary embodiments or a combination thereof, wherein each of the second quantity of field emission cathodes emits an electron current directed toward the anode when it is operating, and the method modulates the current emitted by one or more of the second quantity of field emission cathodes such that the intensity of electrons emitted into a second focal region is modulated.

[0047] Exemplary Embodiment 30: A multimodal X-ray source apparatus comprising an anode and a field emission cathode apparatus located spaced apart from the anode and positioned to emit electrons toward the anode, the field emission cathode apparatus being switchable between an imaging mode in which electrons are focused to a first focal region on the anode, wherein the first focal region has a first focal region size, and an output mode in which electrons are focused to a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size.

[0048] Exemplary Embodiment 31: The apparatus according to any of the preceding exemplary embodiments or a combination thereof, comprising a plurality of individually controllable field emission cathodes, wherein the field emission cathode apparatus is configured such that the imaging mode includes a first amount of field emission cathodes which are operated to direct the electrons emitted thereby toward a first focal region on the anode.

[0049] Exemplary Embodiment 32: The apparatus according to any of the preceding exemplary embodiments or a combination thereof, wherein the field emission cathode apparatus is configured to include a second amount of field emission cathodes greater than a first amount, the output mode of which is operated to direct the electrons emitted thereby toward a second focal region.

[0050] Exemplary Embodiment 33: An apparatus according to any of the preceding exemplary embodiments or a combination thereof, wherein a second amount of field emission cathodes are arranged to direct electrons emitted thereby to corresponding focal regions on the anode, and the corresponding focal regions are arranged adjacently on the anode and arranged to form a second focal region on the anode.

[0051] Exemplary Embodiment 34: An apparatus according to any of the preceding exemplary embodiments or combinations thereof, wherein each of the second quantity of field emission cathodes emits an electron current directed toward the anode when in operation, and the electron current emitted by one or more selected of the second quantity of field emission cathodes is modulable such as to modulate the intensity of electrons thereby emitted into a second focal region.

[0052] These and other features, aspects, and advantages of the Disclosure will become apparent from reading the following detailed description together with the accompanying drawings, which are briefly described below. The Disclosure includes any combination of two, three, four, or more features or elements described herein, whether such features or elements are expressly combined or otherwise enumerated in the description of a particular embodiment herein. The Disclosure is intended to be read as a whole so that, unless the context of the Disclosure clearly indicates otherwise, any separable feature or element of the Disclosure in any aspect or embodiment is considered as intended, i.e., as separable.

[0053] It will be understood that this summary is provided solely for the purpose of summarizing several exemplary embodiments to provide a basic understanding of the disclosure. Therefore, it will be understood that the above-described exemplary embodiments are merely examples and should not be construed in any way as narrowing the scope or intent of the disclosure. It will be understood that the scope of the disclosure includes, in addition to those summarized herein, many potential embodiments, some of which are further described below. Furthermore, other embodiments disclosed herein and the advantages of such embodiments will become apparent from the following detailed description, together with the accompanying drawings illustrating the principles of the described embodiments.

[0054] As described above, this disclosure has been explained using general terminology, but here we will refer to the attached drawings, which are not necessarily drawn to a consistent scale. [Brief explanation of the drawing]

[0055] [Figure 1] A typical illustrative prior art X-ray source, including a metal anode (such as tungsten or molybdenum), an electron cathode, and in some examples, an electron focusing electrode, is schematically shown. [Figure 2A] An X-ray source according to one aspect of the present disclosure is schematically shown, the field emission cathode apparatus comprising a plurality of individually controllable field emission cathodes, one of which field emission cathodes can be operated to provide imaging X-rays from a first field of view (Figure 2A), then that field emission cathode is deactivated, and another field emission cathode is operated to provide imaging X-rays from a different field of view (Figure 2B). [Figure 2B] An X-ray source according to one aspect of the present disclosure is schematically shown, the field emission cathode apparatus comprising a plurality of individually controllable field emission cathodes, one of which field emission cathodes can be operated to provide imaging X-rays from a first field of view (Figure 2A), then that field emission cathode is deactivated, and another field emission cathode is operated to provide imaging X-rays from a different field of view (Figure 2B). [Figure 3] Figures 2A and 2B schematically show an X-ray source according to an embodiment of the present disclosure, in which individual field emission cathodes (or small groups of field emission cathodes) can be operated sequentially to provide imaging X-rays from multiple viewing angles. [Figure 4A] A schematic representation of an X-ray source according to one aspect of the present disclosure, the field emission cathode apparatus comprises a plurality of individually controllable field emission cathodes, many (or all) of which are operated simultaneously to generate a large focus / ray on the anode for the delivery of radiotherapy treatment. [Figure 4B] A schematic X-ray source according to an embodiment of the present disclosure is shown in Figure 4A, in which only some (or some group of) field emission cathodes are selectively activated (the rest are deactivated) (Figure 4B) to distribute the radiation dose to the target, and the electron current from each field emission cathode or each group of field emission cathodes is modulated to generate intensity-modulated radiation (IMRT) along a large focus / line. [Figure 4C] A schematic X-ray source according to an embodiment of the present disclosure is shown in Figure 4A, in which only some (or some group of) field emission cathodes are selectively activated (the rest are deactivated) (Figure 4B) to distribute the radiation dose to the target, and the electron current from each field emission cathode or each group of field emission cathodes is modulated to generate intensity-modulated radiation (IMRT) along a large focus / line. [Figure 5] A schematic representation of a method for providing multiple operating modes for an X-ray source device according to one aspect of this disclosure is provided. [Figure 6A] A schematic representation of an X-ray source, configured in therapeutic / output mode and operated to deliver radiotherapy treatment to a target, is shown in one aspect of this disclosure. [Figure 6B] Figure 6A schematically shows an X-ray source configured in treatment / output mode according to an aspect of the present disclosure, the X-ray source having a single large focus / ray on the anode and emitting directed X-ray radiation through a single slit collimator in order to deliver radiotherapy treatment to a target. [Figure 6C] Figure 6A schematically shows an X-ray source configured in treatment / output mode according to an embodiment of the present disclosure, the X-ray source having multiple large focal points / rays on the anode and emitting directed X-ray radiation through a slit collimator having multiple slits in order to deliver radiotherapy treatment to a target. [Figure 7A] A schematic representation of an X-ray source arranged in imaging mode according to one aspect of the present disclosure is shown, which is configured to emit directed X-ray radiation through a cone-beam collimator and has a small focal point mounted on the anode for imaging a target as shown in the cross-sectional view. [Figure 7B] A schematic representation of an X-ray source arranged in imaging mode according to one aspect of the present disclosure is shown, which is configured to emit directed X-ray radiation through a cone-beam collimator and has a small focal point mounted on the anode to image a target as shown in the sagittal diagram. [Figure 8A]A schematic representation of a radiotherapy system including a multimodal X-ray source according to one aspect of this disclosure is provided. [Figure 8B] Figure 8A schematically illustrates a radiotherapy system according to an embodiment of the present disclosure, in which the X-ray source and X-ray detector are mounted on a gantry, and the gantry and / or patient are movable relative to each other to facilitate target alignment / positioning relative to the X-ray source. [Figure 8C] Figure 8A schematically shows a radiotherapy system according to an embodiment of the present disclosure, in which the X-ray source and X-ray detector are mounted on a gantry, and the X-ray source and / or X-ray detector are movable relative to each other to facilitate alignment / positioning of the target relative to the X-ray source. [Figure 9] A method for providing multimodal X-ray therapy to a target, according to one aspect of this disclosure, is schematically shown. [Figure 10] Figure 8A schematically shows a radiotherapy system according to an embodiment of the present disclosure, in which a gantry is mounted with a plurality of X-ray sources and a plurality of corresponding X-ray detectors facing the X-ray detectors. [Figure 11] A schematic representation of a radiotherapy system according to one aspect of the present disclosure is shown, wherein the X-ray source is configured to form both an imaging and a treatment focus on the anode, and a single collimator having both a cone-beam collimator and a slit collimator is associated with the X-ray source so that imaging and radiotherapy can be performed simultaneously. [Figure 12(a)] A schematic representation of a radiotherapy system according to one aspect of this disclosure is shown, in which a single slit collimator is implemented for both therapeutic and imaging purposes. [Figure 12(b)] A schematic representation of a radiotherapy system according to one aspect of this disclosure is shown, in which a single slit collimator is implemented for both therapeutic and imaging purposes. [Figure 12(c)] A schematic representation of a radiotherapy system according to one aspect of this disclosure is shown, in which a single slit collimator is implemented for both therapeutic and imaging purposes. [Figure 13A]A single slit collimator (Figure 13A) is used to align with the original diagnostic image of the target / tumor (Figure 13B), and the images of the target / tumor generated by the radiotherapy system in the manner of disclosure shown in Figures 12(a) to 12(c) are schematically shown. [Figure 13B] A single slit collimator (Figure 13A) is used to align with the original diagnostic image of the target / tumor (Figure 13B), and the images of the target / tumor generated by the radiotherapy system in the manner of disclosure shown in Figures 12(a) to 12(c) are schematically shown. [Figure 14] A schematic representation of a radiotherapy system according to one aspect of this disclosure is shown, in which an X-ray source is mounted on a robotic arm. [Modes for carrying out the invention]

[0056] Herein, this disclosure is described more fully with reference to the accompanying drawings, which illustrate some, though not all, embodiments of this disclosure. In fact, these disclosures may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided to satisfy the applicable legal requirements of this disclosure. Similar numbers refer to similar elements throughout.

[0057] One aspect of the present disclosure comprises a multimodal X-ray source apparatus, collectively denoted by reference numeral 100 (see, for example, Figures 2A and 2B). In some aspects, such an X-ray source apparatus 100 comprises an anode 200 and a field emission cathode apparatus 300 located apart from the anode 200 and arranged such that the field emission cathode apparatus 300 emits electrons (e.g., an electron beam 305) toward the anode 200.

[0058] In one embodiment, the field emission cathode apparatus 300 comprises a plurality of individually controllable field emission cathodes 310. Thus, since X-ray imaging generally requires a small focal size on the anode 200 to provide higher resolution for imaging, the X-ray source apparatus 100 can operate in imaging mode, in which case just one field emission cathode 310 or a few, several, or otherwise few field emission cathodes 310 of the field emission cathode apparatus 300 can be activated to achieve a relatively small focal point (e.g., less than a millimeter to a few millimeters in diameter) of the electron beam(s) 305 on the anode 200 for imaging purposes (see, for example, Figure 2A) and obtain a view of the target from one imaging angle. In some configurations of the X-ray source 100, different single field emission cathodes 310 (or different few, several, or otherwise few field emission cathodes 310) may be activated to achieve different views of the target from different field angles, as shown in Figure 2B. In imaging mode, the energy of the X-ray source (for example, the energy is proportional to the voltage applied to anode 200) can be adjusted to an appropriate range for imaging (e.g., approximately 30kV to 160kV) to achieve suitable X-ray imaging results. In some embodiments, as shown in Figure 3, for example, multiple views of the target can be obtained from various field angles, for example, for three-dimensional (3D) imaging purposes. That is, as shown in Figure 3, one or a few groups of field-emission cathodes can be operated sequentially to generate a series of X-ray images from different field angles. These images can be processed and combined as needed to reconstruct and achieve a 3D view of the target object.

[0059] In another aspect of this disclosure, the X-ray source 100 can operate in therapeutic mode or power mode to generate a relatively large focal spot of the electron beam 305 on the anode 200. That is, in some cases, many (or all) of the multiple field emission cathodes 310 can be operated simultaneously, with each emitted electron beam directed toward adjacent or overlapping focal spots on the anode 200, resulting in the combination of focal spots / regions on the anode 200 struck by the electron beam 305 to form a common large focal spot or focal line (e.g., up to several tens of centimeters) on the anode 200, as shown, for example, in Figure 4A. The large focal spot / line allows the X-ray source 100 to operate at a relatively high power output, providing a proportionally higher dose rate (e.g., above 40 Gy / second) as power. For example, the energy of the X-ray source 100 is increased by increasing the voltage applied to the anode 200 to a relatively higher level (e.g., approximately 160kV to 800kV) to achieve a favorable radiation dose rate distribution across the target for better treatment outcomes.

[0060] In some embodiments, the X-ray source 100 in treatment / output mode may have only some of its field emission cathodes 310 selectively activated, as shown in Figure 4B, for example, while the rest of the field emission cathodes 310 remain inactive. In addition, the current from each activated field emission cathode (the flow of electrons in the electron beam) (and thus the X-ray radiation emitted from the corresponding focal point on the anode 200) can be programmed / modulated to have different intensity levels, as shown in Figure 4C, for example. This selective field emission cathode activation and electron beam modulation operation mode of the X-ray source 100 results in different radiation intensities from the corresponding focal points, as shown in Figure 4C, thereby enabling the achievement of intensity-modulated radiotherapy (IMRT) capability in the SFRT treatment protocol.

[0061] One embodiment of the multi-model X-ray source 100 may include a field emission cathode device 300 that can switch between an imaging mode in which the emitted electron / electron beam 305 is focused on a first focal region on the anode 200, the first focal region having a first focal region size, and an output mode or treatment mode in which the emitted electron / electron beam 305 is focused on a second focal region on the anode 200, the second focal region having a second focal region size larger than the first focal region size.

[0062] In one embodiment, the field emission cathode apparatus 300 comprises a plurality of individually controllable field emission cathodes 310 configured and arranged such that the imaging mode includes a first amount of field emission cathodes 310 which are operated to direct the electrons emitted thereby (electron beam 305) to a first focal region on the anode 200. In a further embodiment, the field emission cathode apparatus 300 is configured such that the output mode includes a second amount of field emission cathodes 310 which are operated to direct the electrons emitted thereby (electron beam 310) to a second focal region on the anode 200. The second amount of field emission cathodes 310 is greater than the first amount of field emission cathodes 310. Furthermore, the second quantity field emission cathodes 310 are positioned to direct the electrons (electron beam or current) emitted thereby to their respective corresponding focal regions on the anode 200, the respective corresponding focal regions being adjacent to each other on the anode 200 and positioned to form a second focal region on the anode 200. In a further embodiment, each cathode of the second quantity field emission cathodes 310 is operated to provide a current / electron beam of electrons directed to the anode 200, and the current from one or more selected of the second quantity field emission cathodes 310 is moduloable to modulate the intensity of electrons thereby emitted to the second focal region. Thus, the first and second quantity field emission cathodes 305 in the field emission cathode apparatus 300 can be selected and positioned to provide appropriate focal sizes on the anode 200 for imaging mode and treatment / output mode, respectively, and the appropriate energy for each mode is determined based on the voltage applied to the anode 200.

[0063] Another aspect of the present disclosure provides a method for providing a plurality of modes of an X-ray source device 100, as shown in Figure 5, the X-ray source device 100 including an anode 200 and a field emission cathode device 300 that is spaced apart from the anode 200 and arranged to emit electrons toward the anode 200. Such a method includes arranging the field emission cathode device 300 in imaging mode to focus electrons onto a first focal region on the anode 200, the first focal region having a first focal region size (block 510), and reversibly switching the arrangement of the field emission cathode device 300 to output mode to focus electrons onto a second focal region on the anode 200, the second focal region having a second focal region size larger than the first focal region size (block 520).

[0064] In some embodiments, the field emission cathode apparatus 300 comprises a plurality of individually controllable field emission cathodes 310, and the step of setting up the field emission cathode apparatus 300 in imaging mode includes activating a first amount of field emission cathodes 310 to direct the electrons emitted thereby to a first focal region on the anode 200. In other embodiments, the field emission cathode apparatus 300 comprises a plurality of individually controllable field emission cathodes 310, and the step of switching the setting up the field emission cathode apparatus 300 in output mode includes activating a second amount of field emission cathodes 310 to direct the electrons emitted thereby to a second focal region, wherein the second amount is greater than the first amount. In yet another embodiment, the step of directing electrons to a second focal region includes directing electrons from each of the second quantity of field emission cathodes 310 to their respective corresponding focal regions on the anode 200, the respective corresponding focal regions being adjacent to each other on the anode 200 and arranged to form or combine a second focal region on the anode. In yet another embodiment, each of the second quantity of field emission cathodes 310 emits an electron current that is directed to the anode 310 when it is operating, and the method includes modulating the electron current emitted by one or more selected of the second quantity of field emission cathodes 310 to modulate the intensity of the electrons or electron current thereby emitted to the second focal region on the anode 200.

[0065] Accordingly, embodiments of the multimodal X-ray source 100 disclosed herein include the ability to reversibly switch the same X-ray source between imaging mode and treatment / output mode by programming the control of the field emission cathode apparatus 300 to allow selective operation of one or more of the field emission cathodes 310 of the field emission cathode apparatus 300. This selective operation capability of the field emission cathodes 310 of the field emission cathode apparatus 300 can be achieved in many different ways, such as disclosed in concurrently pending U.S. Patent Application No. 18 / 247,265, assigned to NCX Corporation, entitled "Multi-Beam X-ray Source and Method for Forming Same," which is incorporated herein by reference. For example, multiple individually addressable and operable field emission cathodes can be implemented for multimode operation of the X-ray source 100. In this way, the dual mode can be configured to suitably change the size of the electron beam focus on the anode 200 so that a smaller focus is used for imaging mode and a larger focus is used for radiotherapy treatment in treatment / output mode.

[0066] For example, as shown in Figure 6A, an X-ray source 100 configured to implement a large focal point on its anode is used for radiotherapy treatment with the X-ray source in therapeutic / power mode. In some embodiments, the large focal point size may be cumulative in that it can direct the electron beam(s) to a single focal point / line on the anode, or it can direct the electron beam(s) to multiple focal points / lines on the anode, and the multiple focal points / lines provide a cumulative large focal point for the X-ray source 100 in therapeutic / power mode. In therapeutic mode, relatively higher dose rates are often preferred for treating the patient (e.g., the tumor as the "target"). The large focal point / line implemented via the X-ray source in therapeutic mode allows the X-ray source 100 to operate at relatively higher power (higher anode voltage, higher electron current, and longer exposure time / duty cycle). A slit collimator 600 is used to generate the spatially discrete X-ray beam required for SFRT treatment (e.g., to extend the dose to the periphery of the tumor / target). Figures 6A–6C show detectors 700 facing the X-ray source 100 so that the target / tumor 750 is positioned between them; however, in practice, the detectors 700 are optional and can be repositioned or removed when the X-ray source 100 is in treatment / output mode. In addition to the X-ray source 100 being positioned and configured in treatment / output mode so that the electron current is directed to a single focus / line or multiple focus / lines on the anode, the slit collimator 600 for directing the X-ray beam(s) emitted by the X-ray source 100 may be configured to have a single slit opening (see, e.g., Figure 6B) or multiple slit openings (see, e.g., Figure 6C). If the emitted X-ray beam(s) directed through the slit collimator 600 does not extend sufficiently to irradiate the tumor 750, the X-ray source 100 and / or the patient may be translated / moved during the treatment procedure so that the X-ray beam(s) irradiate the entire tumor (see, e.g., Figure 6B). Otherwise, radiotherapy treatment can be divided into several subtreatments, each subtreatment covering a portion of the target / tumor.In other words, in such cases, the X-ray source 100 can be positioned and actuated to deliver a first dose of radiation to a first portion of the target / tumor 750. Then, the deactivated X-ray source 100 is shifted / translated, then positioned and actuated to deliver a second dose of radiation to a second portion of the target / tumor 750, and the process is repeated to provide radiotherapy treatment to the entire target / tumor 750.

[0067] For example, as shown in Figures 7A and 7B, an X-ray source 100 configured to implement a small focal point on its anode is used to image a target / tumor 750 when the X-ray source is in imaging mode. The smaller focal point on the anode is more suitable for imaging purposes because it provides higher spatial resolution for imaging. In addition, in imaging mode, the X-ray source 100 can operate at relatively lower power (e.g., lower anode voltage, lower electron current, and shorter exposure time / duty cycle) so that the anode can withstand the power requirements associated with a smaller focal point. In some embodiments, a cone-beam collimator 625 is used to define a field of view size for imaging so that the X-ray beam(s) emitted by the X-ray source 100 are directed and detected by the detector 700.

[0068] In some embodiments, the multimodal X-ray source 100 can be incorporated into a patient treatment system 400, as shown, for example, in Figure 8A. Such a system 400 may include a gantry 410 for supporting the X-ray source 100 in a position opposite to the X-ray detector 700. A couch / table 420 is positioned adjacent to the gantry 410 to support the patient so that the target / tumor 750 is positioned between the X-ray source 100 and the X-ray detector 700. The couch / table 420 may be movable laterally (e.g., movable in a horizontal plane) to translate the patient to align with the therapeutic and / or imaging X-ray beam(s) emitted by the X-ray source 100. As shown in Figure 8B, the gantry 410 can be configured to be rotatable around a central axis extending through the gantry, parallel to the couch / table 420, so that a pair of X-ray sources 100 / X-ray detectors 700 can be swung around the patient to treat and / or image the tumor / target from different directions. In some cases, as shown in Figure 8C, the gantry 410 may be configured to allow the X-ray sources 100 and / or X-ray detectors 700 to be moved perpendicular to the central axis (e.g., shifted perpendicular or laterally to the central axis). That is, Figure 8C schematically shows that the X-ray sources 100 and / or X-ray detectors 700 can be mounted on rails 710 so that their respective distances from the central axis can be adjusted. The adjustable distance provides flexibility for achieving the optimal treatment and / or imaging position. For example, a relatively larger distance between the X-ray sources 100 and the central axis (e.g., the imaging center) provides a larger radiation field for treatment and imaging (e.g., a dimensionally larger X-ray beam). In another example, a relatively small distance between the X-ray source 100 and the central axis / imaging center increases the radiation dose rate for treatment and imaging.

[0069] The computer workstation / controller 430 communicates with the couch / table 420, gantry 410, X-ray source 100, and X-ray detector 700 to manage, for example, radiation therapy planning, as well as the delivery and control of radiation therapy. Such functions include, for example, aligning and moving a patient via a couch / table 420 and / or gantry 410; switching the X-ray source 100 between imaging mode and treatment / output mode; moving the X-ray detector 700 independently of the X-ray source 100 (e.g., to move the X-ray detector 700 away when the X-ray source 100 is in treatment / output mode); moving the X-ray detector 700 independently of or simultaneously with moving the X-ray source 100 (e.g., shifting the X-ray source 100 and / or X-ray detector 700 perpendicular or laterally with respect to the central axis); controlling the X-ray source 100 and X-ray detector 700 as needed in both imaging mode and treatment / output mode; and processing the X-ray beam detected by the X-ray detector 700 to form a desired image of the target 750. In certain embodiments, the X-ray source 100 is controllable by the controller 430 so that the X-ray source 100, and therefore the system 400, can be seamlessly switched between a treatment / output mode and an imaging mode to provide real-time imaging-guided radiotherapy (IGRT). In some embodiments, those skilled in the art will understand that the switching between the treatment / output mode and the imaging mode with respect to the system 400 also includes switching of a collimator, for example, between a cone-beam collimator (imaging) and a slit collimator (treatment / output).

[0070] In an example workflow related to the treatment system 400 shown in Figure 8A, an SFRT treatment plan is first generated using the workstation / controller 430 based on the required system 400 and patient information. Once the treatment plan is complete, it is stored in the workstation / controller 430 and / or transferred to the system 400 for treatment delivery and control. Before initiating SFRT treatment, the patient is positioned on the couch / table 420 according to the treatment plan and system 400 configuration. Then, to facilitate patient setup (e.g., to determine the spatial location and extent of the target / tumor relative to the X-ray source 100), a set of X-ray images is acquired using the X-ray source 100 operating in imaging mode (small focus of electron beam on the anode). Once the patient is properly positioned and aligned, the X-ray source 100 is switched to treatment / output mode (large focus / line of electron beam(s) on the anode) for radiotherapy (SFRT) treatment. During SFRT treatment, the operation of system 400, which is in treatment / output mode, can be temporarily suspended, and the X-ray source 100 can be switched to imaging mode to confirm the placement of the patient (e.g., the target to be treated, a reference marker, etc.). If the patient / target placement does not correspond to the placement for which the treatment plan has been formed, the patient / target will be realigned and positioned before the X-ray source 100 is switched back to treatment / output mode and resumes SFRT treatment.

[0071] One aspect of the present disclosure, schematically shown in Figure 9, includes a method for providing multimodal X-ray therapy to a target 750 within an object (e.g., a patient) using an X-ray apparatus including an X-ray source 100 and an X-ray detector 700, wherein the X-ray source 100 includes an anode 200 and a field emission cathode device 310 spaced apart from the anode 200 and arranged to emit electrons 305 toward the anode 200, and the target 750 is determined from a diagnostic image of the target 750 obtained by diagnostic imaging of the object. Such a method involves positioning the field emission cathode device 310 of the X-ray source 100 in imaging mode to focus electrons 305 onto a first focal region on the anode 200, the first focal region having a first focal region size (block 910); positioning the field emission cathode device 300 of the X-ray source 100 in imaging mode to focus electrons 305 onto a first focal region on the anode 200, the first focal region having a first focal region size (block 920); and operating the X-ray source 100 in imaging mode to emit the imaging X-ray beam toward the X-ray detector 700 so that the imaging X-ray beam interacts with the target 750 to obtain a first X-ray image of the target 750. The process includes imaging 50 (block 930), adjusting the X-ray source 100 or the object in response to a comparison between the first X-ray image and the diagnostic image of the target 750 to align the target 750 with the diagnostic image of the target 750 and directing the X-ray source 100 toward the target 750 (block 940), switching the configuration of the field emission cathode device 300 to output mode to focus electrons 305 onto a second focal region on the anode 200, wherein the second focal region has a second focal region size larger than the first focal region size, and operating the X-ray source 100 in output mode to emit a first therapeutic X-ray beam toward the target 750 and deliver a first dose of X-rays to the target 750.

[0072] In some embodiments, such a method includes, after delivering a first dose of X-rays to the target 750, switching the configuration of the field emission cathode device 300 of the X-ray source 100 to imaging mode; re-imaging the target 750 using the X-ray device to obtain a second X-ray image of the target 750; adjusting the X-ray source 100 or the object in response to a comparison of the second X-ray image with the diagnostic image of the target 750 to align the target 750 with the diagnostic image of the target 750 and directing the X-ray source 100 toward the target 750; switching the configuration of the field emission cathode device 300 to output mode to focus the electrons 305 to a second focal region on the anode 200; and operating the X-ray source 100 in output mode to emit a second therapeutic X-ray beam toward the target 750 and deliver a second dose of X-rays to the target 750.

[0073] In some embodiments, the method includes positioning the X-ray detector 700 opposite the X-ray source 100 when the field emission cathode 300 of the X-ray source 100 is in transmission imaging mode. In other embodiments, the method includes positioning the X-ray detector 700 adjacent to the X-ray source 100 when the field emission cathode 300 of the X-ray source 100 is in backscatter imaging mode. In such cases, the backscatter element (not shown) may be positioned opposite the X-ray source 100 so that the object / target is located between the backscatter element and the X-ray source 100, and the backscatter element is configured / positioned to reflect / return the imaging X-ray(s) toward the X-ray detector 700 positioned adjacent to the X-ray source 100.

[0074] In some embodiments, the method includes positioning the X-ray detector 700 so as not to receive a first or second therapeutic X-ray beam when the field emission cathode apparatus 300 of the X-ray source 100 is in output mode. In other embodiments, adjusting the X-ray source 100 or the object includes adjusting the distance between the X-ray source 100 and the object, adjusting the angular position of the X-ray source 100 in a trajectory around the object, and / or adjusting the position of the X-ray source 100 or the object relative to the other in the lateral direction and nonparallel to the imaging X-ray beam.

[0075] In some embodiments, the margin (e.g., boundary) of the target 750 is determined from the diagnostic imaging. In such embodiments, the method includes collimating the first or second therapeutic X-ray beams emitted by the X-ray source 100 in power mode such that the lateral dimensions of each first and second therapeutic X-ray beam are less than or equal to the lateral dimension of the margin of the target 750 perpendicular to each first and second therapeutic X-ray beam (i.e., the collimator can be implemented to optimize the therapeutic X-ray beam to the size of the target 750 and minimize irradiation of healthy tissue surrounding the target 750). In other embodiments, the step of collimating the first or second therapeutic X-ray beams includes collimating the first or second therapeutic X-ray beams emitted by the X-ray source 100 in power mode using a slit collimator 600 such that the first or second therapeutic X-ray beam is emitted onto the target 750 as a linear region. In yet another embodiment, a cone-beam collimator 625 is used to collimate the first or second imaging X-ray beam emitted by the X-ray source 100 in imaging mode so that the first or second imaging X-ray beam is emitted onto the object as an elliptical or circular region. As disclosed herein, the steps of imaging and re-imaging the target and delivering the first and second X-ray doses are achieved using the same X-ray source 100.

[0076] In some cases, the step of operating the X-ray source 100 in output mode to emit a first or second dose of X-rays to the target 750 includes operating the X-ray source 100 in output mode to emit a first or second dose of X-rays to the target 750 at a predetermined dose rate over a predetermined time, thereby providing the target 750 with a cumulative dose. In other cases, the method includes tracking the movement of an object during the delivery of the first dose of X-rays, and in response to the tracked movement of the object, adjusting the X-ray source 100 or the object to align the target 750 with a diagnostic image of the target 750 and to maintain the X-ray source 100 oriented toward the target 750 (i.e., any movement of the object can be tracked via a reference marker attached to the object so that it remains in a known spatial relationship with the target 750 regardless of the movement of the object).

[0077] To carry out such a method, aspects of the present disclosure include a corresponding multimodal X-ray system 400 for providing X-ray therapy to a target 750 within an object, the target 750 being determined from a diagnostic image of the target 750 obtained by diagnostic imaging of the object. The X-ray system 400 comprises an X-ray detector 700, an X-ray source 100 including an anode 200 and a field emission cathode device 300 spaced apart from the anode 200 and positioned to emit electrons 305 toward the anode 200, and a controller 430 communicating with the X-ray source 100 and the X-ray detector 700. The controller 430 instructs the X-ray source 100 to position the field emission cathode device 300 in imaging mode and focus electrons 305 onto a first focal region on the anode 200, the first focal region having a first focal region size, and images the target 750 by emitting an imaging X-ray beam so that the imaging X-ray beam interacts with the target 750 and is detected by the X-ray detector 700 to obtain a first X-ray image of the target 750, and in response to a comparison between the first X-ray image and the diagnostic image of the target 750, the X-ray source 100 Alternatively, the object is adjusted so that the target 750 is aligned with the diagnostic image of the target 750, the X-ray source 100 is directed toward the target 750, the field emission cathode device 300 is switched to output mode and the X-ray source 100 is instructed to focus the electrons 305 onto a second focal region on the anode 200, the second focal region having a second focal region size larger than the first focal region size, and the X-ray source 100 is operated in output mode to emit a first therapeutic X-ray beam toward the target 750 and deliver a first dose of X-rays to the target 750.

[0078] In some embodiments, the controller 430 is configured to, after a first dose of X-rays has been delivered to the target 750, instruct the X-ray source 100 to switch the configuration of the field emission cathode 300 to imaging mode, to re-image the target 750 using the X-ray apparatus to obtain a second X-ray image of the target 750, and in response to a comparison of the second X-ray image with the diagnostic image of the target 750, adjust the X-ray source 100 or the object to align the target 750 with the diagnostic image of the target 750, orient the X-ray source 100 toward the target 750, switch the configuration of the field emission cathode 300 to output mode to focus the electrons 305 to a second focal region on the anode 200, and operate the X-ray source 100 in output mode to emit a second therapeutic X-ray beam toward the target 750 to deliver a second dose of X-rays to the target 750.

[0079] In some embodiments, when the field emission cathode 300 of the X-ray source 100 is in transmission imaging mode, the X-ray detector 700 is positioned opposite the X-ray source 100, while in other embodiments, when the field emission cathode 300 of the X-ray source 100 is in backscatter imaging mode, the X-ray detector 100 is positioned adjacent to the X-ray source 100. In some embodiments, the X-ray detector 700 is positioned so as not to receive the first or second therapeutic X-ray beam when the field emission cathode 300 of the X-ray source 100 is in output mode (for example, the X-ray detector 700 is deactivated or otherwise moved out of the effective path of the X-ray beam(s) emitted by the X-ray source 100).

[0080] In some embodiments, the controller 430 is configured to adjust the X-ray source 100 or the object by adjusting the distance between the X-ray source 100 and the object, adjusting the angular position of the X-ray source 100 in a trajectory around the object, or adjusting the position of the X-ray source 100 or the object relative to the other in the lateral direction and non-parallel to the imaging X-ray beam.

[0081] In some embodiments, the margin of the target 750 is determined from a diagnostic image, and the system 400 includes a collimator positioned between the X-ray source 100 and the object, the collimator being configured to collimate the first or second therapeutic X-ray beams emitted by the X-ray source 100 in output mode such that the lateral dimensions of each first and second therapeutic X-ray beam are less than or equal to the lateral dimension of the margin of the target 750 perpendicular to each first and second therapeutic X-ray beam. Such a collimator may include a slit-beam collimator 600 configured to collimate the first or second therapeutic X-ray beams emitted by the X-ray source 100 in output mode such that the first or second therapeutic X-ray beam is emitted onto the target 750 as a linear region. In other embodiments, such a collimator may include a cone-beam collimator 625 positioned between the X-ray source 100 and the object, configured to collimate the first or second imaging X-ray beam emitted by the X-ray source 100 in imaging mode so that the first or second imaging X-ray beam is emitted onto the object as an elliptical or circular region. In some embodiments, imaging and re-imaging of the target 750, as well as delivery of the first and second X-ray doses, are performed using the same X-ray source 100.

[0082] In some embodiments, the controller 430 is configured to operate the X-ray source 100 in output mode to emit a first or second dose of X-rays to the target 750 at a predetermined dose rate over a predetermined period of time, thereby providing a cumulative dose to the target 750. In other embodiments, a tracking device (e.g., a reference marker detectable by the X-ray device in imaging mode, or a reference marker and detector system communicating with the controller 430) is included to communicate with the controller 430 and is configured to track the movement of an object during the delivery of the first dose of X-rays, and the controller 430 is configured to adjust the X-ray source 100 or the object in response to the tracked movement of the object to align the target 750 with the diagnostic image of the target 750 and to keep the X-ray source 100 oriented toward the target 750.

[0083] Many modifications and other embodiments of the disclosures described herein will be conjured to those skilled in the art, having benefit from the teachings presented in the foregoing description and the associated drawings. For example, instead of a single X-ray source 100 / single X-ray detector 700 pair mounted on the gantry 410, some aspects of the present disclosure may include multiple X-ray sources 100 and corresponding X-ray detectors 700 mounted on the gantry 410, as shown in Figure 10. Such a configuration can provide multiple radiotherapy treatments to a target / tumor 750 from different directions / angles, for example, to achieve higher dose rates over shorter treatment times. Imaging of the target 750 can also be performed from different directions / angles, and / or the target 750 can be imaged by a pair of X-ray sources 100 / X-ray detectors 700 while a second X-ray source 100 is providing radiotherapy treatment to the target / tumor 750 (e.g., simultaneously).

[0084] In another example, the X-ray source 100 may be configured to simultaneously generate both therapeutic and imaging X-ray beams, as shown in Figures 11A and 11B. More specifically, in one example, the X-ray source 100 may configure / program a specific field emission cathode 310 of the field emission cathode apparatus 300 to form two small foci on the anode 200 for imaging purposes, with these two small foci on either side of three larger foci / lines formed by activating another group of field emission cathodes for radiotherapy therapeutic purposes. Such a configuration may allow the radiotherapy therapeutic X-ray beam and the imaging X-ray beam to be collimated independently using a single fixed collimator assembly 650 (e.g., including a cone-beam collimator 625 and a slit collimator 600 in a single assembly, arranged to minimize overlap between the imaging and therapeutic X-ray beams). The imaging X-ray beam can be activated during treatment (e.g., while the radiotherapy therapeutic X-ray beam(s) are activated) to provide real-time imaging guidance and feedback without interrupting radiotherapy. Two corresponding X-ray detectors 705 can also be mounted on the gantry 410 and used to capture the imaging X-ray beam to provide imaging guidance and feedback during treatment.

[0085] In yet another example, a slit collimator 600 can be implemented for imaging purposes during radiotherapy treatment. As shown in Figure 12(a), a single slit collimator 600 (which may have one or more slits) is used for both treatment and imaging. During radiotherapy treatment, the X-ray source 100 can be configured and positioned, as shown in Figure 12(b), to activate a group of field emission cathodes 310 to form a large focal point / line, which is aligned with the slits defined by the collimator 600 for therapeutic X-ray beam generation. During subtreatment of the target / tumor 750, the field emission cathode apparatus 300 can be switched to imaging mode, resulting in the activation of one or a small group of field emission cathodes 310 to form a small focal point on the anode 200. As shown in Figure 12(c), in imaging mode, the small focal point helps in high-resolution imaging acquisition. The pattern of the small focal point remains selected to match the pattern of slits in the slit collimator 600. In such cases, the imaging X-ray beam, directed through the slit of the slit collimator 600 and detected by the X-ray detector 700, results in the generation of an incomplete / partial image of the target 750, as shown in Figure 13A, due to interference from the portion of the slit collimator 600 that defines the slit (e.g., the bar of the slit collimator). The partial image, including the portion of the target / tumor 750, can still be aligned to the original diagnostic image of the target / tumor 750 (see, for example, Figure 13B), and thus can still provide imaging guidance and feedback during radiotherapy.

[0086] In yet another example, as shown in Figure 14, the X-ray source 100 may be mounted on a robotic arm 1000 instead of a gantry, allowing for greater flexibility and freedom of movement when positioning the X-ray source 100 in three-dimensional (3D) space for optimal interaction with the target / tumor 750. In such a configuration, a corresponding X-ray detector may be mounted on another robotic arm (not shown) to provide imaging guidance and feedback during radiotherapy and / or while the X-ray source 100 is moving due to the movement of the robotic arm 1000. In other examples, a corresponding X-ray detector may be mounted adjacent to the X-ray source 100 on the same robotic arm 1000, and the X-ray source 100 may be configured to utilize backscatter modes for the purposes of X-ray imaging, imaging guidance, and feedback.

[0087] Therefore, it should be understood that this disclosure is not limited to the specific embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Certain terms are used herein, but they are used in a general and descriptive sense only and not for limiting purposes.

Claims

1. A method for providing multimodal X-ray therapy to a target within an object using an X-ray apparatus including an X-ray source and an X-ray detector, wherein the X-ray source includes an anode and a field emission cathode apparatus spaced apart from the anode and arranged to emit electrons toward the anode, the target is determined from a diagnostic image of the target obtained by diagnostic imaging of the object, and the method is The field emission cathode apparatus of the X-ray source is positioned in imaging mode to focus the electrons onto a first focal region on the anode, wherein the first focal region has a first focal region size. The target is imaged by operating the X-ray source in the imaging mode and emitting the imaging X-ray beam toward the X-ray detector so that the imaging X-ray beam interacts with the target and a first X-ray image of the target is obtained, In response to the comparison between the first X-ray image and the diagnostic image of the target, the X-ray source or the object is adjusted to align the target with the diagnostic image of the target and direct the X-ray source toward the target. Switching the arrangement of the field emission cathode apparatus to output mode, thereby focusing the electrons to a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size. The X-ray source is operated in the output mode to emit a first therapeutic X-ray beam toward the target, and a first dose of X-rays is delivered to the target. Methods that include...

2. After delivering the first dose of X-rays to the target, the arrangement of the field emission cathode apparatus of the X-ray source is switched to the imaging mode, The target is re-imaged using the aforementioned X-ray apparatus to obtain a second X-ray image of the target. In response to the comparison of the second X-ray image with the diagnostic image of the target, the X-ray source or the object is adjusted to align the target with the diagnostic image of the target and to direct the X-ray source toward the target. Switching the arrangement of the field emission cathode device to the output mode, and focusing the electrons to the second focal region on the anode, The X-ray source is operated in the output mode to emit a second therapeutic X-ray beam toward the target, and a second dose of X-rays is delivered to the target. The method according to claim 1, including the method described in claim 1.

3. The method according to claim 1, further comprising arranging the X-ray detector so as to face the X-ray source when the field emission cathode device of the X-ray source is in transmission imaging mode.

4. The method according to claim 1, further comprising arranging the X-ray detector adjacent to the X-ray source when the field emission cathode device of the X-ray source is in backscatter imaging mode.

5. The method according to claim 2, further comprising arranging the X-ray detector so as not to receive the first therapeutic X-ray beam or the second therapeutic X-ray beam when the field emission cathode apparatus of the X-ray source is in the output mode.

6. The method according to claim 2, wherein adjusting the X-ray source or the object includes adjusting the distance between the X-ray source and the object, adjusting the angular position of the X-ray source in a trajectory around the object, or adjusting the position of the X-ray source or the object relative to the other in the lateral direction and non-parallel to the imaging X-ray beam.

7. The method according to claim 2, wherein the margin of the target is determined from the diagnostic imaging, and the method includes collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in the output mode such that the lateral dimensions of each of the first therapeutic X-ray beam and the second therapeutic X-ray beam are less than or equal to the lateral dimension of the margin of the target perpendicular to each of the first therapeutic X-ray beam and the second therapeutic X-ray beam.

8. The method according to claim 7, wherein collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam includes collimating the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in the output mode using a slit collimator such that the first therapeutic X-ray beam or the second therapeutic X-ray beam is emitted onto the target as a linear region.

9. The method according to claim 2, wherein operating the X-ray source in the output mode to emit a first X-ray dose or a second X-ray dose to the target includes operating the X-ray source in the output mode to emit a first X-ray dose or a second X-ray dose to the target at a predetermined X-ray dose rate over a predetermined period of time, thereby providing the target with a cumulative X-ray dose.

10. The method according to claim 2, comprising imaging and re-imaging the target and delivering the first X-ray dose and the second X-ray dose using the same X-ray source.

11. The method according to claim 2, comprising using a cone-beam collimator to collimate the first imaging X-ray beam or the second imaging X-ray beam emitted by the X-ray source in the imaging mode such that the first imaging X-ray beam or the second imaging X-ray beam is emitted onto the object as an elliptical or circular region.

12. Tracking the movement of the object during the delivery of the first dose of X-rays, In response to the tracked movement of the object, the X-ray source or the object is adjusted to align the target with the diagnostic image of the target and maintain the X-ray source oriented toward the target. The method according to claim 1, including the method described in claim 1.

13. A multimodal X-ray system for providing X-ray therapy to a target within an object, wherein the target is determined from a diagnostic image of the target obtained by diagnostic imaging of the object, and the X-ray system is X-ray detector and An X-ray source including an anode and a field emission cathode device that is spaced apart from the anode and arranged to emit electrons toward the anode, A controller that communicates with the X-ray source and the X-ray detector, The field emission cathode apparatus is positioned in imaging mode and the X-ray source is instructed to focus the electrons to a first focal region on the anode, wherein the first focal region has a first focal region size. The target is imaged by operating the X-ray source in the imaging mode and emitting the imaging X-ray beam such that the imaging X-ray beam interacts with the target and is detected by the X-ray detector to obtain a first X-ray image of the target. In response to the comparison between the first X-ray image and the diagnostic image of the target, the X-ray source or the object is adjusted to align the target with the diagnostic image of the target, and the X-ray source is directed toward the target. The arrangement of the field emission cathode apparatus is switched to output mode and the X-ray source is instructed to focus the electrons into a second focal region on the anode, wherein the second focal region has a second focal region size that is larger than the first focal region size. The X-ray source is operated in the output mode to emit a first therapeutic X-ray beam toward the target, and a first dose of X-rays is delivered to the target. A controller and, A multimodal X-ray system equipped with [specific features / equipment].

14. The aforementioned controller After the first dose of X-rays has been delivered to the target, the X-ray source is instructed to switch the arrangement of the field emission cathode apparatus to the imaging mode. Using the aforementioned X-ray apparatus, the target is re-imaged to obtain a second X-ray image of the target. In response to the comparison between the second X-ray image and the diagnostic image of the target, the X-ray source or the object is adjusted to align the target with the diagnostic image of the target, and the X-ray source is directed toward the target. The arrangement of the field emission cathode apparatus is switched to output mode, and the X-ray source is instructed to focus the electrons onto the second focal region on the anode. The X-ray source is operated in the output mode to emit a second therapeutic X-ray beam toward the target, and a second dose of X-rays is delivered to the target. The system according to claim 13, configured as described above.

15. The system according to claim 13, wherein the X-ray detector is positioned to face the X-ray source when the field emission cathode device of the X-ray source is in transmission imaging mode.

16. The system according to claim 13, wherein the X-ray detector is positioned adjacent to the X-ray source when the field emission cathode device of the X-ray source is in backscatter imaging mode.

17. The system according to claim 14, wherein the X-ray detector is positioned so as not to receive the first therapeutic X-ray beam or the second therapeutic X-ray beam when the field emission cathode device of the X-ray source is in the output mode.

18. The system according to claim 14, wherein the controller is configured to adjust the X-ray source or the object by adjusting the distance between the X-ray source and the object, adjusting the angular position of the X-ray source in a trajectory around the object, or adjusting the position of the X-ray source or the object relative to the other in the lateral direction and non-parallel to the imaging X-ray beam.

19. The system according to claim 14, wherein the margin of the target is determined from the diagnostic imaging, and the system comprises a collimator positioned between the X-ray source and the object, the collimator being configured to collimate the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in the output mode such that the lateral dimensions of each of the first therapeutic X-ray beam and the second therapeutic X-ray beam are less than or equal to the lateral dimension of the margin of the target perpendicular to each of the first therapeutic X-ray beam and the second therapeutic X-ray beam.

20. The system according to claim 19, wherein the collimator includes a slit-beam collimator configured to collimate the first therapeutic X-ray beam or the second therapeutic X-ray beam emitted by the X-ray source in the output mode such that the first therapeutic X-ray beam or the second therapeutic X-ray beam is emitted onto the target as a linear region.

21. The system according to claim 14, wherein the controller is configured to operate the X-ray source in the output mode to emit a first X-ray dose or a second X-ray dose at a predetermined X-ray dose rate over a predetermined period of time, thereby providing a cumulative X-ray dose to the target.

22. The system according to claim 14, wherein imaging and re-imaging of the target and delivery of the first and second X-ray doses are performed using the same X-ray source.

23. The system according to claim 14, further comprising a cone-beam collimator positioned between the X-ray source and the object, and configured to collimate the first imaging X-ray beam or the second imaging X-ray beam emitted by the X-ray source in the imaging mode such that the first imaging X-ray beam or the second imaging X-ray beam is emitted onto the object as an elliptical or circular region.

24. The system according to claim 13, comprising a tracking device configured to communicate with the controller and track the movement of the object during the delivery of the first dose of X-rays, wherein the controller is configured to adjust the X-ray source or the object in response to the tracked movement of the object to align the target with the diagnostic image of the target and to keep the X-ray source directed toward the target.

25. A method for providing multiple modes of an X-ray source apparatus, wherein the X-ray source apparatus includes an anode and a field emission cathode apparatus located spaced apart from the anode and arranged to emit electrons toward the anode, The field emission cathode device is positioned in imaging mode to focus the electrons onto a first focal region on the anode, wherein the first focal region has a first focal region size. The arrangement of the field emission cathode device is reversibly switched to an output mode to focus the electrons to a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size, and the switching is reversible. Methods that include...

26. The method according to claim 25, wherein the field emission cathode device comprises a plurality of individually controllable field emission cathodes, and positioning the field emission cathode device in the imaging mode includes activating a first amount of the field emission cathodes to direct the electrons thereby emitted toward a first focal region on the anode.

27. The method according to claim 26, wherein the field emission cathode device comprises a plurality of individually controllable field emission cathodes, and switching the arrangement of the field emission cathode device to the output mode includes activating a second amount of the field emission cathodes to direct the electrons thereby emitted to the second focal region, wherein the second amount is greater than the first amount.

28. The method according to claim 27, wherein directing the electrons to the second focal region includes directing the electrons from each of the second amount of field emission cathodes to the respective corresponding focal regions on the anode, the respective corresponding focal regions being adjacent to each other on the anode and arranged to form the second focal region on the anode.

29. The method of claim 28, wherein each of the second quantity of field emission cathodes emits an electron current directed toward the anode when it is operating, and the method modulates the current emitted by one or more of the second quantity of field emission cathodes such that the intensity of the electrons emitted toward the second focal region is modulated.

30. A multimodal X-ray source device, A-scatter, A field emission cathode device positioned at a distance from the anode and configured to emit electrons toward the anode, wherein the device is switchable between an imaging mode in which the electrons are focused to a first focal region on the anode, wherein the first focal region has a first focal region size, and an output mode in which the electrons are focused to a second focal region on the anode, wherein the second focal region has a second focal region size larger than the first focal region size. A multimodal X-ray source system equipped with the following features.

31. The apparatus according to claim 30, wherein the field emission cathode apparatus comprises a plurality of individually controllable field emission cathodes, wherein the imaging mode includes a first amount of the field emission cathode which is operated to direct the electrons emitted thereby toward the first focal region on the anode.

32. The apparatus according to claim 31, wherein the field emission cathode apparatus is configured to include a second amount of the field emission cathode, greater than the first amount, which is operated to direct the electrons emitted thereby toward the second focal region.

33. The apparatus according to claim 32, wherein the second amount of field emission cathodes is arranged to direct the electrons emitted thereby to corresponding focal regions on the anode, and the corresponding focal regions are arranged adjacently on the anode and are arranged to form the second focal region on the anode.

34. The apparatus according to claim 33, wherein each of the second quantity of field emission cathodes emits an electron current directed toward the anode when in operation, and the electron current emitted by one or more selected of the second quantity of field emission cathodes is modulated such as to modulate the intensity of the electrons thereby emitted into the second focal region.

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