System and X-ray system

Abstract

The present invention provides a system that can enable tomosynthesis used in either or both of the following applications: lower-dose three-dimensional (3D) imaging (e.g., "3D" mammography), and higher-dose two-dimensional (2D) imaging and magnified imaging. [Solution] Some embodiments include a system having a plurality of X-ray sources, each X-ray source including an electron source configured to generate an electron beam and a target configured to receive the electron beam and convert the electron beam into an X-ray beam, wherein the first X-ray source is different from the second X-ray source, and the target of the X-ray source is part of a linear target.

Description

Background Art

[0001] Stationary tomography can be performed using a multi-source x-ray tube. Such a multi-source x-ray tube can include multiple emitters such as nanotube emitters. Although tomography can be performed using a multi-source x-ray tube, there may be insufficient dose for performing certain higher-dose two-dimensional (2D) imaging.

Brief Description of the Drawings

[0002] [Figure 1] A block diagram of a system with multiple x-ray sources according to some embodiments. [Figure 2] A block diagram of a system with multiple x-ray sources according to some other embodiments. [Figure 3A] A block diagram of a system with an x-ray source that includes multiple emitters according to some other embodiments. [Figure 3B] A block diagram of a system with an x-ray source that includes multiple emitters according to some other embodiments. [Figure 4] A block diagram of a system with an x-ray source that includes smaller emitters according to some embodiments. [Figure 5] A block diagram of a system with an x-ray source that includes larger emitters according to some embodiments. [Figure 6A] A block diagram of a system with an x-ray source that has a target with multiple regions according to some embodiments. [Figure 6B] A block diagram of regions of a target with different inclinations according to some embodiments. [Figure 7] A block diagram of a system with an x-ray source that has a target with multiple regions and includes different cooling systems according to some embodiments. [Figure 8] A block diagram of a system with an x-ray source that includes multiple vacuum enclosures according to some embodiments. [Figure 9] This is a block diagram of an imaging system according to several embodiments. [Figure 10] This is a block diagram of an imaging system according to several other embodiments. [Figure 11] This is a flowchart of techniques for operating a system with multiple X-ray sources, according to several embodiments. [Figure 12] This is a block diagram of a system with multiple X-ray sources according to several embodiments. [Modes for carrying out the invention]

[0003] Some embodiments relate to an X-ray source having multiple X-ray beams (representing different doses). Embodiments described herein may enable tomosynthesis used for lower-dose three-dimensional (3D) imaging (e.g., "3D" mammography), as well as for higher-dose two-dimensional (2D) imaging and magnified imaging, or both. Various electron emitter-anode configurations can be used with X-ray sources of various X-ray beams suitable for various applications.

[0004] Figure 1 is a block diagram of a system with multiple X-ray sources according to several embodiments. System 100a includes multiple X-ray sources 101a having emitters 102 and 104 and a target 106. System 100a may include other components, electronic equipment, vacuum housing, etc., but these are not shown for clarity.

[0005] Emitters 102 and 104 may be any variety of emitters. For example, emitters 102 and 104 may each include a filament (e.g., a coiled filament emitter), a low work function (LWF) emitter, a field emitter, a dispenser cathode, a photoemitter, and so on. Emitters 102 and 104 may be the same type of emitter or different types of emitters. For example, emitter 102 may be a field emitter used for tomosynthesis, and emitter 104 may be a filament used for 2D and / or magnified imaging.

[0006] Target 106 is a structure configured to generate X-rays in response to incident electron beams such as electron beams 108 and 110. Target 106 may include materials such as tungsten (W), molybdenum (Mo), rhodium (Rh), silver (Ag), rhenium (Re), and palladium (Pd). In some embodiments, target 106 is a linear target with a length:width (or length:height) aspect ratio, where the length of the target is 2, 5, 10, 20, or 50 times the width (or height) of the target. In some embodiments, the linear target may be flat or curved, such as a continuous curve, a piecewise linear curve, or a combination of such curves. In some embodiments, electron beams 108 and 110 from emitters 102 and 104, respectively, may collide with different sections or parts of target 106. In some embodiments, electron beams 108 and 110 from emitters 102 and 104 may collide with at least 3, 5, or 10 different sections or parts of the target 106.

[0007] In some embodiments, the X-rays emitted from the X-ray source 101 can be directed to a common location. For example, the X-ray source 101 may be oriented within a housing, gantry, or other structure so that the X-rays are directed to a single point or area. When the system 100a is installed, the point or area may be the location where an object, specimen, patient, etc., is placed. In some embodiments, the system may be mounted on a stationary structure or gantry. The placement and orientation of the X-ray source 101 may reduce the need to rotate the system around the object, specimen, patient, etc.

[0008] The combination of emitter 102 or 104 and target 106 forms an X-ray source 101a. For example, X-ray source 101a-0 includes emitter 104 and target 106. Each of X-ray sources 101a-1 to 101a-n includes the corresponding emitter 102-1 to 102-n and target 106. Although a single target 106 is shown as an example, each X-ray source 101 may include different regions of target 106 or separate targets 106, as will be described in more detail below. As will be described in more detail below, X-ray sources 101 may have other embodiments such as different configurations of emitter 102 or 104, different targets 106 and / or regions of target 106, such that at least one of the X-ray sources 101 is different from another of the X-ray sources 101. Here, x-ray source 101a-0 differs from x-ray sources 101a-1 to 101a-n in that emitter 102 is different from emitter 104. In some embodiments, emitter 102 may be the same. Thus, only one of the x-ray sources 101a, i.e., x-ray source 101a-0, differs from the others. However, in some embodiments, each of the x-ray sources 101 may be different. In other embodiments, different combinations of emitters 102 and 104 may be the same, while others may be different.

[0009] Emitters 102 and 104 may be similar, but they are configured such that the maximum current of the first electron beam 108 from one of the emitters 102 at the first focal spot on the target 106 is different from the second maximum current of the second electron beam 110 at the second focal spot on the target 106.

[0010] The maximum current is the maximum current achievable by the configuration of the individual emitters 102 or 104 and the corresponding parts of the target 106. In some embodiments, emitters 102 and 104 can operate to have the same operating current, but emitters 102 and 104 and / or target 106 can also be configured to have different maximum currents achievable by emitters 104 and target 106. For example, one or more of the emitters 102 may have a maximum current that cannot be achieved by the configuration of emitter 104, or emitter 104 may have a maximum current that cannot be achieved by one or more of the emitters 102.

[0011] In some embodiments, system 100a includes at least one emitter 102 and a single emitter 104. As will be described in more detail below, emitters 102 and 104 may have some similarities, but in operation, and in combination with the corresponding focal spot and target portion 106, the emitter-target combination has the maximum current.

[0012] In some embodiments, the maximum current from emitter 104 and the corresponding portion of target 106 is greater than the maximum current from a single emitter 102, such as emitter 102-1, and the corresponding portion of target 106. In other embodiments, the maximum current from emitter 102 is greater than that from emitter 104 due to the reverse flow of relative maximum currents. The relationship between the maximum currents can be 1.5 times, 2 times, 10 times, 100 times, or more.

[0013] In some embodiments, the maximum current of electron beam 110 may be greater than or less than the maximum current of one of the electron beams 108. Therefore, even in the same portion of target 106, electron beam 108 may generate a different maximum current on target 106 than electron beam 110. For example, the maximum current of electron beam 108 may be about 30 milliamperes (mA), while the maximum current of electron beam 110 may be about 100 mA. In one example, the maximum current (e.g., first maximum current) of the electron beam (e.g., 110) from a first electron source (e.g., 101a-0) may be at least twice, three times, five times, ten times, twenty times, fifty times, or even one hundred times greater than the maximum current (e.g., second maximum current) of the electron beam (e.g., 108) from a second electron source (e.g., 101a-1). For example, the electron beam 108 from emitter 102 may be used for lower-dose tomosynthesis, and the electron beam 110 from emitter 104 may be used for higher-dose 2D and / or magnified imaging.

[0014] System 100a can include any number of emitters 102, represented by emitters 102-1 to 102-n, where n is any integer greater than 1. In some embodiments, the number of emitters 102 is one or at least two. In some embodiments, the number of emitters 102 may be approximately 25. In other embodiments, the number may vary based on various factors such as layout, configuration, and application.

[0015] In some embodiments, emitters 102 and 104 may be arranged in a flat, one-dimensional array. In other embodiments, emitters 102 and 104 may be arranged in a curve such as a continuous curve, a piecewise linear curve, or a combination of such curves. In some embodiments, emitters 102 and 104 may be arranged in a two-dimensional array, or a combination of a one-dimensional array and a two-dimensional array. In some embodiments, the arc of the emitter may extend from approximately + / - 15 degrees to approximately + / - 90 degrees around a center point. The target 106 may be formed in a manner corresponding to the one-dimensional or two-dimensional array of emitters 102 and 104.

[0016] In some embodiments, emitter 104 is located at the center of emitter 102. However, in other embodiments, emitter 104 may be located at a different position. For example, emitter 104 may be located at the edge of the array of emitters 104, offset from the center of emitter 104, etc.

[0017] In some embodiments, system 100a may be used for different applications. For example, in one set of operations, emitters 102 and 104 may operate to generate substantially the same current on target 106. Such applications may be used to generate tomographic images. However, in other operations such as two-dimensional mammography, two-dimensional projected images may be desired. For such images, higher X-ray intensity may be desired. Since emitter 104 is configured differently from emitter 102, system 100a can be used for both types of operations.

[0018] FIG. 2 is a block diagram of a system with multiple emitters according to some other embodiments. System 100b may be similar to system 100a described above. However, in some embodiments, system 100b may include an x-ray source 101b-0 with multiple emitters 104 (other x-ray sources 101 similar to 101a-1 to 101a-n are not shown in this figure or other figures for clarity). Here, two emitters 104-1 and 104-2 are shown, but in other embodiments, the number may be greater than two. Each emitter 104 may be configured to generate a corresponding electron beam 110. In some embodiments, the electron beams 110 may be focused and / or steered onto the same portion of the target 106, such as on the same focal spot on the target 106. Focusing and / or steering the electron beams 110 onto the same portion of the target 106 may be performed by structural features (e.g., emitter cavities) and / or electrical features (e.g., focusing electrodes) of the emitter 104 and / or magnetic or electrostatic mechanisms, etc.

[0019] In some embodiments, one of the emitters 104, such as emitter 104-1, may be similar to emitter 102. However, emitter 104-2 may be different, such as being larger or smaller. As a result, the maximum current on the target may be different because emitter 104-2 is different.

[0020] In some embodiments, both emitters 104-1 and 104-2 may be different from emitter 102. For example, emitter 104-1 may be smaller and / or configured to generate a smaller focal spot on target 106, and emitter 104-1 may be larger and / or configured to generate a larger focal spot on the target. In some operations, emitter 104-1 with a smaller focal spot may be used for high-resolution imaging, and larger emitter 104-2 may be used for two-dimensional imaging such as mammography.

[0021] Figures 3A through 3B are block diagrams of systems with x-ray sources including multiple emitters, according to some other embodiments. In some embodiments, system 100c may be similar to system 100b described above. However, the emitter 104 of the x-ray source 101c-0 may include one or more focusing electrodes 112 configured to focus the electron beam 110 onto different focal spots on the target 106. In some operations, the focusing electrodes 112 may be controlled to focus each of the electron beams 110 onto different focal spots on the target 106, as shown in FIG. 3A.

[0022] However, in other operations, as shown in FIG. 3B, the focusing electrodes 112 can also be controlled to focus the electron beam 110 onto a single focal spot. As a result, the effective maximum current on that focal spot is higher than that of a single emitter 104. Although two emitters 104 are used as an example, more emitters 104 may be used in other embodiments. In some embodiments, a sufficient number of emitters 104 can be grouped together to achieve the desired total current. For example, the emitters 104 may be arranged in a two-dimensional array.

[0023] Although some embodiments have been described in which the focusing electrodes 112 can be controlled to focus the electron beam 110 onto a single focal spot or multiple focal spots on the target 106, in other embodiments, the focusing may be fixed. For example, the focusing may be set to focus the electron beam 110 onto a single focal spot. During operation, any number of emitters 104 from zero to all of the emitters 104 can be controlled to selectively emit the electron beam 110 by the focusing electrodes 112 (this combination can be called a grid) or other components specific to the type of emitter 104. As a result, the effective current on a single focal spot can be controlled by controlling which emitter 104 emits the electron beam 110 towards a single focal spot.

[0024] Figure 4 is a block diagram of a system with an X-ray source including a smaller emitter, according to several embodiments. System 100d may be similar to system 100a described above. However, in some embodiments, emitter 104d may be smaller than emitter 102. Emitter 104d may be configured to provide an electron beam 110d with a lower maximum current. In some embodiments, electron beam 110d may have a smaller focal spot size. A smaller focal spot size may enable higher resolution than other electron beams 108. As a result, electron beam 110d and the resulting X-ray beam can be used for high-resolution imaging.

[0025] Figure 5 is a block diagram of a system with an X-ray source including a larger emitter, according to several embodiments. System 100e may be similar to system 100a described above. However, in some embodiments, the maximum current of emitter 104e may be greater than the maximum current of emitter 102. As a result, the larger current may enable two-dimensional imaging, such as two-dimensional mammography.

[0026] Many variations of the emitter configuration that result in different maximum currents on target 106 have been described above. As will be described in more detail below, target 106 may include different configurations for different parts of target 106 in order to achieve different maximum currents. Embodiments in which emitters 102 and 104 have electron beams 108 and 110 with the same or similar currents will be described, but in other embodiments, different maximum currents can be achieved by various combinations of emitter and target configurations.

[0027] Figure 6A is a block diagram of a system with an X-ray source having a target with multiple regions, according to several embodiments. System 100f may be similar to system 100a described above. However, in some embodiments, emitter 104 of X-ray source 101f-0 may be the same as emitter 102 of X-ray source 101f-1. Each of emitters 102 and 104 is configured to emit a corresponding electron beam 108 or 110 toward different regions of target 106f, which are here identified as regions 106f-0 to 106f-n. Regions 106f-0 to 106f-n are part of X-ray sources 101f-0 to 101f-n. Here, emitters 102-1 to 102-n are configured to emit electron beams 108-1 to 108-n toward the corresponding regions 106f-1 to 106f-n, and emitter 104 is configured to emit electron beam 110 toward region 106f-0.

[0028] Regions 106f-0 to 106f-n are shown as adjacent, but in some embodiments, the spacing between regions may differ. Furthermore, in some embodiments, the focal spots generated by electron beams 108 or 110 may be separated rather than overlapping.

[0029] Figure 6B is a block diagram of target regions having different inclinations according to several embodiments. Referring to Figures 6A and 6B, in some embodiments, region 106f-0 may have a different inclination than another region, such as region 106f-1. In this example, region 106f-0 has a shallower inclination than region 106f-1. As a result, the effective current density on the target in region 106f-0 is smaller than that in region 106f-1, although the current is the same for the corresponding electron beams 108-1 and 110. In some embodiments, the current in electron beam 110 from emitter 104 may be relatively larger compared to electron beam 108-1. The increased current may be due to a larger size of emitter 104. Electron beam 110 may have a larger focal spot on region 106f-0 of target 106 compared to region 106f-1. However, because the slope of region 106f-0 is smaller than that of region 106f-1, the focal spot size of the X-ray beam 114-0 may be smaller than that of the X-ray beam 114-1. As a result, in some embodiments, the X-ray beam 114-0 can be generated using a higher current while maintaining a similar X-ray focal spot size to that of the X-ray beam 114-1. Furthermore, as the current of the electron beam 110 increases, the area over which it spreads within region 106f-0 of the target 106 may increase. Consequently, in some embodiments, the current over region 106f-0 may result in a lower current density on region 106f-0 than when a larger current is focused to a smaller focal spot, due to the larger area over which it spreads. A lower current density on region 106f-0 can increase the stability of the target 106, for example, by reducing the temperature and heat flux of the target 106. In some embodiments, the configurations of regions 106f-1 to 106f-n may be similar, but the configuration of region 106f-0 may be different from the respective configurations of regions 106f-1 to 106f-n.

[0030] While a shallower slope for region 106f-0 is used as an example, the configuration may differ in other embodiments. For example, region 106f-0 may have a steeper slope compared to regions 106f-1 through 106f-n.

[0031] Referring back to Figure 6A, in some embodiments, region 106f-0 may contain a different material from the material of regions 106f-1 through 106f-n. As mentioned above, various different materials may be used as the target 106f, or the target may be supported using various different materials suitable for more efficient heat transfer, such as copper (Cu). Using any of these materials can create material differences between regions 106f.

[0032] In certain examples, region 106f-0 may be formed of tungsten (W). Regions 106f-1 to 106f-n may be formed of a tungsten-rhodium alloy. As described above, in some embodiments, the maximum current of the beam 110 on target 106f-0 may be greater than that of the other regions 106f-1 to 106f-n. Therefore, a material such as tungsten with higher thermal properties, such as having a higher melting point, can be used for region 106f-0. However, rhodium (Rh) may have a more desirable X-ray spectrum for certain applications such as mammography. Therefore, rhodium can be used as part of regions 106f-1 to 106f-n that do not receive the electron beam 108 with a high maximum current. Thus, in some embodiments, the material may be selected based on thermal properties and / or X-ray emission spectrum.

[0033] Figure 7 is a block diagram of a system with an X-ray source having a target with multiple regions, including different cooling systems according to several embodiments. System 100g may be similar to system 100f described above. However, system 100g may include a cooling system 116g adjacent to region 106f-1 and configured to cool at least that region 106f-0. For example, cooling system 116g may include a fluid cooling system such as a water cooling system, an evaporative cooling system, or a phase-change material. In some embodiments, other parts of target 106f may be cooled. However, since higher maximum currents may result in more heat being generated in region 106f-0, additional cooling of that region 106f-0 may be provided.

[0034] In some embodiments, the regions 106f can be spaced apart from each other. For example, the spacing between regions 106f may be a portion of the length of the regions 106f, such as about 5%, 10%, or more. In some embodiments, the spacing between regions 106f may be the same or different. In some embodiments, the spacing between region 106f-0 and other regions 106f may be different from the spacing between those other regions 106f.

[0035] In some embodiments, cost reductions may be possible by allowing two different configurations within a single system 100, such as X-ray sources 100a to 100g. Regardless of whether the desired operation results in a higher or lower maximum current, the combination within a single system 100 may reduce complexity, allow for the inclusion of more uniform components, reduce costs, and so on. Furthermore, this combination may allow for additional use while maintaining the previous use of other X-ray sources. For example, a user accustomed to using a particular X-ray source for two-dimensional imaging can continue to use that operation while obtaining the additional benefits mentioned above, such as tomographic imaging, improved image quality due to reduced motion blur, and higher resolution imaging.

[0036] Figure 8 is a block diagram of a system with an X-ray source including multiple vacuum housings, according to several embodiments. In some embodiments, system 100h may be similar to system 100a described above. However, emitter 104 may be in a different vacuum housing 120. Here, emitter 102 is located in vacuum housing 120-1 together with the corresponding target 106h-1. However, emitter 104 is located in vacuum housing 120-2 together with the corresponding target 106h-2. Vacuum housing 120-1 may be adjacent to vacuum housing 120-2 and may be positioned so that the resulting X-rays are directed to substantially the same location. By including emitter 104 in vacuum housing 120-2, which is different from vacuum housing 120-1 containing emitter 102, costs can be reduced by making it possible to replace a faulty and / or worn part of system 100h without replacing the entire system 100h.

[0037] In some embodiments, the first X-ray source strikes a different target or region of a target than the second X-ray source. The first X-ray source may share the same control electronics, power supply, etc.

[0038] In some embodiments, the above-described target is part of a fixed anode. In some embodiments, the above-described target is part of a linear anode.

[0039] Figure 9 is a block diagram of an imaging system according to several embodiments. In some embodiments, the imaging system 200a includes an electron source 205 configured to generate an electron beam 210. The electron beam 210 is directed toward a target 206. The target 206 has a surface 206a positioned at an angle other than perpendicular to the incident electron beam 210. In some embodiments, the target 206 is part of a rotating anode, while in other embodiments, the target 206 may be part of a stationary anode. The electron beam 210 received by the target 206 generates an X-ray beam 270 that passes through a window 280 of the vacuum housing. In some embodiments, the configuration of the electron source 205 and the target 206 may be the same as that of the X-ray source 100 described above, while in other embodiments, the combination may differ. For example, the electron source 205 may include a single emitter.

[0040] The collimator 220a is configured to shape the X-ray beam 270. The shaped X-ray beam 270 includes a central axis 272, a portion 274 closer to the electron source 205, and a portion 276 further away from the electron source 205. The central axis 272 is the direction of the X-rays in the X-ray beam 270, which are generated at an angle perpendicular to the incident electron beam 210. The portions 274 and 276 are at least partially formed by edges 220a-1 and 220a-2 of the collimator 220a. In particular, edge 220a-1 is closer to the electron source 205 than the central axis 272. Edge 220a-2 is further away from the electron source 205 than the central axis 272. Due to the heel effect during the generation of the X-ray beam 270, the intensity of portion 274 may be higher and more uniform than that of portion 276. In portion 276, the intensity may decrease more rapidly closer to edge 220a-2 of the collimator 220a.

[0041] The anode heel effect, or heel effect, refers to the reduction in electric field strength or X-ray flux in the portion of the X-ray beam 270 closer to the anode compared to the cathode or electron source 205, because X-ray emission from the target material decreases at angles greater than perpendicular to the electron beam. The conversion of the electron beam 210 to X-rays occurs not only on the surface of the target material 206 but also within the target material 206. Because X-rays are generated deeper within the target material 206, these X-rays can exit and cross the target material 206 and then return, allowing the X-rays to proceed to the detector 230. More material in the target 206 needs to be crossed at emission angles perpendicular to the electron beam 210 (closer to the target 206) than at emission angles more parallel to the electron beam 210 (closer to the cathode or electron source 205). As the amount of material in the target 206 increases, there is more reabsorption of X-rays by the target material 206, resulting in fewer X-rays reaching the electric field at angles perpendicular to the electron beam 210. In contrast, as the emission angle of the X-rays approaches that of the incident electron beam 210, less of the X-rays pass through the material of the target 206 and less are reabsorbed. Ultimately, this results in a greater electric field strength and X-ray flux directed toward the cathode or electron source 205 than toward the target 206. This non-uniform beam effect, or heel effect, can negatively impact the detection results of X-ray imaging.

[0042] In some embodiments, the X-ray filter 260 may be positioned within the X-ray beam 270. Although the X-ray filter 260 is shown as being downstream of the collimator 220a, in other embodiments, the X-ray filter 260 may be positioned elsewhere. The X-ray filter 260 may contain materials such as molybdenum (Mo), rhodium (Rh), silver (Ag), and aluminum (Al), copper (Cu), stainless steel, or combinations thereof, in varying thicknesses. The X-ray filter 260 may be configured to mitigate the heel effect by adjusting the intensity of the X-ray beam 270 so that portions 274 and 276 are more uniform.

[0043] In some embodiments, the X-ray source 200a is used with the detector 230 to generate an image based on a portion 240 of the patient 250. For example, the portion 240 may be the breast of the patient 250. Due to the positioning of the patient 250 relative to the X-ray beam 270, portion 240' may not be imaged. However, the remainder can be imaged with an X-ray beam in which the effects of intensity fluctuations due to the heel effect (e.g., the heel effect applied to a narrower portion of the breast with lower mass density) are mitigated. For example, the fluctuation due to the heel effect may range from 80% to 100% when the angle of the surface 206a is 15 degrees. Thus, with respect to a given image quality while the X-ray source 200a is operating, the dose received by the patient may be reduced. Furthermore, if a substantially imaging type X-ray beam 270 can be used, it becomes possible to reduce the SID (source-to-image distance: the distance from the X-ray source to the detector), increase the imaging X-ray dose, and reduce the output for the same imaging X-ray dose.

[0044] In some embodiments, smaller angles may be used for the surface 206a of the target 206. For example, if the nanotube (NT) emitter has a size of w1 (width) × l1 (length), the electric focus spot size (FSS) on the surface 206a after electron beam focusing will be w2 (width) × l2 (length). The electron FSS on the surface 206a depends on the design of the focusing electrode; the smaller the NT emitter size (w1 × l1), the smaller the electron FSS on the surface (w2 × l2). An X-ray FSS of w3 (width) × l3 (length) is determined by the angle (θ) between the electron FSS and the surface 206a, where w3 is equal to w2 and l3 is equal to l2xsin(θ). Given an X-ray FSS, a smaller anode angle allows for a larger electron FSS and thus a larger emitter. A larger NT emitter can generate a larger emission current. The larger the electron FSS on surface 206a, the larger the area for distributing the thermal load, which in turn allows for higher output from the tube and higher X-ray dose.

[0045] Therefore, reducing the heel effect allows for a smaller angle to be used on surface 206a. A smaller angle allows for a larger current or size of the emitter in the electron source 205. For example, a larger field emitter size may allow for a larger current to be supplied, but a larger size results in a larger X-ray FSS. However, in the same or similar SID, the dose can be increased despite reducing the angle of surface 206a to maintain the X-ray FSS.

[0046] Figure 10 is a block diagram of an imaging system according to several other embodiments. The imaging system 200b may be similar to the imaging system 200a described above. However, the imaging system 200b includes a collimator 220b having a different configuration. The collimator 220b includes an edge 220b-2 that is substantially aligned with the central axis 272. In other embodiments, the edge 220b-2 may be in a different position, such as being closer to the electron source 205. As a result of the positions of edges 220b-1 and 220b-2 of the collimator 220b, the portion of the X-ray beam 270 leaving the collimator is substantially only portion 274 or a subset of portion 274. The heel effect can mitigate the impact on portion 274, resulting in improved uniformity of the X-rays passing through the collimator 220b. In some embodiments, the uniformity of the X-rays within portion 274 may be sufficient, and the X-ray filter 260 can be omitted. For example, the X-ray intensity can vary from approximately 90% to 100% at a 15-degree angle on the target surface 206a. Furthermore, the imaging system 200b may have higher intensity at the distal end of portion 240.

[0047] In some embodiments, the imaging system 200b allows the patient 250 to be on the opposite side of system 200b from Figure 9. In some embodiments, the use of the distributed electron source 205 as described above may allow for additional space for the patient 250 compared to the electron source 205 using a rotating anode. More space can be left for the patient 250 by reducing the number of external accessories on the patient 250 side of system 200b. For example, more space may be left for the patient 250 by eliminating high-voltage connections, ion pumps, getters, tubing, etc. Furthermore, the use of the distributed electron source 205 allows for the flexibility of not using a rotating anode. As a result, the bearings, rotor, stator, etc. of the rotating anode may not be present on the patient 250 side. The patient 250 can be positioned close to the X-ray beam 270, minimizing the amount of the patient 250's chest wall cropped from the image.

[0048] Referring to Figures 9 and 10, in some embodiments, the collimator 220 may be adjustable. For example, the position of edge 220a-2 / 220b-2 may be adjustable to move the edge from the position in Figure 9 to the position in Figure 10. In other embodiments, other aspects of the collimator may be shifted. For example, the position, aperture, shape, etc., may be adjusted with respect to the central axis 272 and portions 274 and 276 to achieve a desired opening.

[0049] Figure 11 is a flowchart of a technique for operating a system with multiple X-ray sources in several embodiments. At 1100, the first X-ray beam is emitted from the first X-ray source. At 1102, the second X-ray beam is emitted from the second X-ray source. This technique and its variations can be used by the various systems described above. For example, referring to Figures 1 and 11, the emission of the first X-ray beam may be performed by X-ray source 101a-0, and the emission of the second X-ray beam may be performed by X-ray source 101a-1. The emission of the X-ray beams may be caused by the emission of electron beams 108 and 110 from the corresponding emitters 102 and 104.

[0050] Referring to Figures 2 and 11, one of the X-ray beams may be the result of multiple electron beams 110-1 and 110-2 being focused onto the target 106. Referring to Figures 3A, 3B, and 11, in some embodiments, the focusing can be modified so that electron beams 110-1 and 110-2 are focused onto different or the same region of the target 106, thereby generating multiple or a single X-ray beam.

[0051] Figure 12 is a block diagram of a system with multiple X-ray sources according to several embodiments. In some embodiments, the X-ray source 101 may be coupled to control logic 1200. The control logic 1200 may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit, a microcontroller, a programmable logic circuit, a discrete circuit, or a combination of such devices. The control logic 1200 may include external interfaces, such as an address and data bus interface, an interrupt interface, etc. The control logic 1200 may also include other interface devices for connecting the control logic 1200 to internal and external components, such as a logic chipset, a hub, a memory controller, a communication interface, etc. The control logic 1200 may be configured to control various operations described herein. The control logic 1200 may include connections to the X-ray source 101, including connections for applying voltage and / or supplying current to emitters 102 and 104, focusing electrodes 112, a target 106, etc.

[0052] In some embodiments, the emission of the X-ray beam may be the result of emitters of different sizes emitting the electron beam 110 toward the target 106.

[0053] Some embodiments include a system having a plurality of X-ray sources (101), each X-ray source (101) including an electron source (102, 104) configured to generate an electron beam (108, 110), and a target (106) configured to receive the electron beam (108, 110) and convert the electron beam (108, 110) into an X-ray beam, wherein the first X-ray source (101) of the X-ray sources (101) is different from the second X-ray source (101) of the X-ray sources (101).

[0054] In some embodiments, the target (106) of the x-ray source (101) is part of the linear target (106).

[0055] In some embodiments, the aspect ratio of the linear target (106) is at least one of 2:1, 10:1, and 20:1.

[0056] In some embodiments, the linear target (106) is flat, curved, or segmented linear target (106).

[0057] In some embodiments, the x-ray source (101) is positioned such that the corresponding x-ray beam is substantially focused to a single point.

[0058] In some embodiments, the first X-ray source among the plurality of X-ray sources (101) includes at least one field emitter, and another X-ray source (101) among the X-ray sources (101) includes a filament, a low work function emitter, a dispenser cathode, or a photoemitter.

[0059] In some embodiments, the system further includes a collimator (220) configured to collimate the X-ray beams from each of the X-ray sources (101).

[0060] In some embodiments, the first X-ray source (101) of the X-ray sources (101) includes a first electron source (102, 104) having at least one emitter, and the second X-ray source (101) of the X-ray sources (101) includes a second electron source (102, 104) having at least one emitter, and the first electron source (102, 104) and the second electron source (102, 104) are configured such that the first maximum current of the first electron beam (108, 110) from one of the emitters of the first electron source (102, 104) at the first focal spot on the corresponding target (106) is different from the second maximum current of the second electron beam (108, 110) from the second electron source (102, 104) at the second focal spot on the corresponding target (106).

[0061] In some embodiments, the first maximum current is greater than the second maximum current.

[0062] In some embodiments, the first maximum current is greater than the second maximum current by at least one of 2, 10, and 100 times.

[0063] In some embodiments, at least some of the x-ray sources (101) are substantially the same.

[0064] In some embodiments, at least three of the x-ray sources (101) are substantially the same.

[0065] In some embodiments, the first x-ray source (101) includes a first emitter and a second emitter, the first emitter being configured to generate a maximum current higher than the maximum current of the second emitter.

[0066] In some embodiments, the first X-ray source (101) includes a plurality of emitters and a plurality of focusing electrodes (112) configured to focus electron beams (108, 110) from these emitters onto a single focal spot.

[0067] In some embodiments, the first X-ray source (101) includes a plurality of emitters and a plurality of focusing electrodes (112), the plurality of focusing electrodes configured to controllably focus electron beams (108, 110) from these emitters onto a single focal spot, and to controllably focus electron beams (108, 110) from the emitters onto a plurality of focal spots.

[0068] In some embodiments, the system further includes a first vacuum housing (120, 282) having a first X-ray source (101), and a second vacuum housing (120, 282) different from the first vacuum housing (120, 282) having a second X-ray source (101).

[0069] In some embodiments, with respect to at least one of the x-ray sources (101), the surface of the target (106) is positioned at an angle other than perpendicular to the associated electron beam (108, 110), and the first edge of the collimator (220) closest to the electron source (102, 104) is closer to the electron source (102, 104) than the central axis (272) of the x-ray beam before it enters the collimator (220).

[0070] In some embodiments, the second edge of the collimator (220) opposite to the first edge is closer to the electron source (102, 104) than the central axis (272) of the X-ray beam at or before it enters the collimator (220).

[0071] In some embodiments, the position of the collimator (220) relative to the X-ray beam is adjustable.

[0072] In some embodiments, the target (106) of the first X-ray source (101) has a different configuration from the target (106) of the second X-ray source (101).

[0073] In some embodiments, the target (106) of the first X-ray source (101) has a different inclination than the target (106) of the second X-ray source (101).

[0074] In some embodiments, the target (106) of the first X-ray source (101) is made of a different material than the target (106) of the second X-ray source (101).

[0075] In some embodiments, the system further includes a cooling system configured to cool the target (106) of the first X-ray source (101) differently from the target (106) of the second X-ray source (101).

[0076] Some embodiments include a method comprising emitting a first X-ray beam from a first X-ray source (101) having at least a portion of a target (106), and emitting a second X-ray beam from a second X-ray source (101) having at least a portion of a target (106), wherein the first X-ray source (101) is different from the second X-ray source (101).

[0077] In some embodiments, the target is a linear target.

[0078] In some embodiments, emitting a first X-ray beam includes emitting a first X-ray beam through a collimator (220), and emitting a second X-ray beam includes emitting a second X-ray beam through a collimator (220).

[0079] In some embodiments, emitting a first X-ray beam includes emitting a first electron beam (108, 110) toward a target (106) from a first electron source (102, 104) having multiple emitters, and emitting a second X-ray beam includes emitting a second electron beam (108, 110) toward a target (106) from a second electron source (102, 104) having at least one emitter, wherein the first maximum current of the first electron beam (108, 110) at the first focal spot on the target (106) is different from the second maximum current of the second electron beam (108, 110) at the second focal spot on the target (106).

[0080] In some embodiments, at least one emitter of the second electron source (102, 104) includes a first emitter and a second emitter, and further includes emitting a second electron beam (108, 110) from the first emitter of the second electron source (102, 104) with a first current during a first operation, and emitting a second electron beam (108, 110) from the second emitter of the second electron source (102, 104) with a second current greater than the first current during a second operation.

[0081] In some embodiments, the first operation is a three-dimensional imaging operation, and the second operation is a two-dimensional imaging operation.

[0082] In some embodiments, at least one emitter of the second electron source (102, 104) includes a plurality of emitters, further comprising focusing the electron beam (108, 110) from the emitters of the second electron source (102, 104) onto a second focal spot.

[0083] In some embodiments, the first maximum current is smaller than the second maximum current.

[0084] In some embodiments, the X-ray beam generated in response to the second electron beam (108, 110) is collimated by the collimator (220) such that at least a portion of the X-ray beam passes between the edge of the collimator (220) and the central axis (272) of the X-ray beam near the second electron source (102, 104).

[0085] Some embodiments include a system having a plurality of means for emitting an electron beam and means for generating X-rays in response to the electron beam, wherein a first combination of a first means for emitting an electron beam and means for generating X-rays in response to the electron beam is different from a second combination of a second means for emitting an electron beam and means for generating X-rays in response to the electron beam. Examples of means for emitting an electron beam include electron sources 102 and 104, etc. Examples of means for generating X-rays in response to the electron beam include a target 106, etc.

[0086] In some embodiments, the first maximum current in the means for generating X-rays of the first electron beam from one of the means for emitting an electron beam is different from the second maximum current of the second electron beam from another of the means for emitting an electron beam.

[0087] In some embodiments, the system further includes means for collimating the X-ray beam. An example of means for collimating the X-ray beam is a collimator 220.

[0088] Some embodiments include a system comprising an electron source (102, 104) having multiple emitters and a target (106), wherein the emitters of the electron source (102, 104) are configured to emit electrons toward multiple focal spots on separate regions of the target (106), and at least one of the separate regions of the target (106) has a configuration different from at least one other of the separate regions.

[0089] Some embodiments include a system comprising a first electron source (102, 104) having at least one emitter, a second electron source (102, 104) having at least one emitter, and a target (106), wherein each emitter of the first electron source (102, 104) and the second electron source (102, 104) is configured to emit electrons toward the target (106), and the first electron source (102, 104) and the second electron source (102, 104) are configured such that the first maximum current of the first electron beam (108, 110) from one of the emitters of the first electron source (102, 104) at a first focal spot on the target (106) is different from the second maximum current of the second electron beam (108, 110) from the second electron source (102, 104) at a second focal spot on the target (106).

[0090] While structures, devices, methods, and systems are described according to specific embodiments, those skilled in the art will readily recognize that many modifications are possible to specific embodiments, and therefore any modifications should be considered to fall within the spirit and scope disclosed herein. Accordingly, many modifications can be made by those skilled in the art without departing from the spirit and scope of the appended claims.

[0091] The claims following the disclosure in this document are hereby explicitly incorporated into the disclosure in this document, and each claim stands as a separate embodiment in itself. This disclosure includes all variations of the independent claims with dependent claims. Furthermore, additional embodiments that can be derived from the following independent and dependent claims are also explicitly incorporated into the description in this document. These additional embodiments are determined by replacing the dependency of a given dependent claim with the phrase "any of the claims beginning with claim [x] and ending with the claim immediately preceding this claim," where the parenthetical term "[x]" is replaced with the number of the most recently described independent claim. For example, for a first set of claims beginning with independent claim 1, claim 4 may depend on either claims 1 and 3, and these separate dependencies may result in two different embodiments; claim 5 may depend on any one of claims 1, 3, or 4, and these separate dependencies may result in three different embodiments; claim 6 may depend on any one of claims 1, 3, 4, or 5, and these separate dependencies may result in four different embodiments, and so on.

[0092] The description of a feature or element in a claim as "first" does not necessarily imply the existence of a second or additional such feature or element. Embodiments of the invention for which exclusive ownership or privilege is claimed are defined as follows: (Other possible items) (Item 1) A system including multiple X-ray sources, Each X-ray source is, An electron source configured to generate an electron beam, and A target configured to receive the electron beam and convert the electron beam into an X-ray beam, Includes, The first X-ray source among the aforementioned X-ray sources is different from the second X-ray source among the aforementioned X-ray sources, The system wherein the target of the X-ray source is part of a linear target. (Item 2) The system according to item 1, wherein the aspect ratio of the linear target is at least one of 2:1, 10:1, and 20:1. (Item 3) The system according to item 1 or 2, wherein the X-ray source is arranged such that the corresponding X-ray beam is substantially focused to a single point. (Item 4) The first X-ray source among the plurality of X-ray sources includes at least one field emitter, Another X-ray source among the aforementioned X-ray sources is a system according to any one of items 1 to 3, including a filament, a low work function emitter, a dispenser cathode, or a photoemitter. (Item 5) The first X-ray source among the X-ray sources includes a first electron source having at least one emitter, The second X-ray source among the aforementioned X-ray sources includes a second electron source having at least one emitter, The system according to any one of items 1 to 4, wherein the first electron source and the second electron source are configured such that the first maximum current of the first electron beam from one of the emitters of the first electron source at a first focal spot on the corresponding target is different from the second maximum current of the second electron beam from the second electron source at a second focal spot on the corresponding target. (Item 6) The system according to item 5, wherein the first maximum current is greater than at least one of 2, 10, or 100 times the second maximum current. (Item 7) At least some of the aforementioned X-ray sources are substantially the same, The system according to any one of items 1 to 6, wherein at least three of the aforementioned X-ray sources are substantially the same. (Item 8) The first X-ray source includes a first emitter and a second emitter, The system according to any one of items 1 to 7, wherein the first emitter is configured to generate a maximum current higher than the maximum current of the second emitter. (Item 9) The first X-ray source is, Multiple emitters, and Multiple focusing electrodes configured to controllably focus the electron beam from the emitter onto a single focal spot, and to controllably focus the electron beam from the emitter onto multiple focal spots, A system including any one of items 1 through 8. (Item 10) First vacuum housing having the first X-ray source, A second vacuum housing, separate from the first vacuum housing, having the second X-ray source, The systems described in any one of items 1 through 9, further including the systems described in item 1 through 9. (Item 11) For at least one of the aforementioned X-ray sources, The surface of the target is positioned at an angle different from that perpendicular to the associated electron beam. The system according to any one of items 1 to 10, wherein the first edge of the collimator closest to the electron source is closer to the electron source than the central axis of the X-ray beam before it enters the collimator. (Item 12) The system according to item 11, wherein the second edge of the collimator, which is on the opposite side of the first edge, is located in the electron source or is closer to the electron source than the central axis of the X-ray beam before it enters the collimator. (Item 13) The target of the first X-ray source has a different inclination than the target of the second X-ray source, and / or The system according to any one of items 1 to 11, wherein the target of the first X-ray source is made of a different material from the material of the target of the second X-ray source. (Item 14) The system according to any one of items 1 to 13, further comprising a cooling system configured to cool the target of the first X-ray source differently from the target of the second X-ray source. (Item 15) Emitting a first X-ray beam from a first X-ray source that includes at least a portion of the target, and Emitting a second X-ray beam from a second X-ray source that includes at least a portion of the aforementioned target, A method including, Unlike the second X-ray source, the first X-ray source is The aforementioned target is a linear target, method. (Item 16) Emitting the aforementioned first X-ray beam includes emitting a first electron beam toward a target from a first electron source comprising a plurality of emitters, Emitting the second X-ray beam includes emitting a second electron beam toward the target from a second electron source including at least one emitter, The method according to item 15, wherein the first maximum current of the first electron beam at the first focal spot on the target is different from the second maximum current of the second electron beam at the second focal spot on the target. (Item 17) The at least one emitter of the second electron source includes a first emitter and a second emitter, During the first operation, the second electron beam is emitted from the first emitter of the second electron source with a first current, and During the second operation, the second electron beam is emitted from the second emitter of the second electron source with a second current higher than the first current. The method described in item 16, further including the method described in item 16. (Item 18) The at least one emitter of the second electron source includes a plurality of emitters, The method according to item 16 or 17, further comprising focusing the electron beam from the emitter of the second electron source onto the second focal spot. (Item 19) Multiple means for emitting an electron beam, Means for generating X-rays in response to the electron beam, A system that includes, A system in which a first combination of a first means for emitting an electron beam and a means for generating X-rays in response to the electron beam is different from a second combination of a second means for emitting an electron beam and a means for generating X-rays in response to the electron beam. (Item 20) The system as described in item 19, wherein the first maximum current in the means for generating the X-rays of the first electron beam from one of the means for emitting the electron beam is different from the second maximum current of the second electron beam from another of the means for emitting the electron beam.

Claims

1. It consists of multiple X-ray sources, A first electron source configured to generate a first electron beam, A plurality of X-ray sources, including a second electron source configured to generate a second electron beam, The target, The first electron beam is received, and the first electron beam is converted into a first X-ray beam. The target is configured to receive the second electron beam and convert the second electron beam into a second X-ray beam, Collimator and A filter positioned downstream of the collimator, A first focusing electrode is provided, The surface of the target is positioned at an angle different from that perpendicular to the first electron beam. The first edge of the collimator closest to the first electron source is closer to the first electron source than the central axis of the first X-ray beam before it enters the collimator. The second edge of the collimator opposite to the first edge is located on the central axis of the first X-ray beam before it enters the collimator, or is located closer to the first electron source than the central axis of the first X-ray beam before it enters the collimator. The first edge of the filter closest to the first electron source has a first thickness, The second edge of the filter opposite to the first edge has a second thickness that is smaller than the first thickness. The first electron source is configured to guide the first electron beam through the first focusing electrode, The second electron source is configured to guide the second electron beam to the target without passing it through a focusing electrode. system.

2. The first X-ray source among the plurality of X-ray sources differs from the second X-ray source among the plurality of X-ray sources, The aforementioned target is a linear target. The system according to claim 1.

3. The system according to claim 1 or 2, wherein the filter comprises at least one of molybdenum (Mo), rhodium (Rh), silver (Ag), aluminum (Al), copper (Cu), or stainless steel.

4. The first X-ray source among the plurality of X-ray sources operates at the first maximum current, The system according to any one of claims 1 to 3, wherein the second X-ray source among the plurality of X-ray sources operates with a second maximum current different from the first maximum current.

5. The system according to claim 4, further comprising a cooling system configured to provide different cooling to a first region of the target associated with the first X-ray source and a second region of the target associated with the second X-ray source.

6. The third X-ray source among the plurality of X-ray sources operates at the first maximum current, The first X-ray source and the third X-ray source are generated by the first electron beam and the third electron beam focused on the first region of the target, The system according to claim 4 or 5, wherein the second X-ray source is generated by the second electron beam guided to a second region of the target different from the first region.

7. The system according to claim 6, wherein the first focusing electrode is configured to focus the first electron beam and the third electron beam without focusing the second electron beam.

8. The first surface of the target is parallel to the longitudinal axis of the target and is positioned at a first angle with respect to the first electron beam. The second surface of the target is parallel to the longitudinal axis of the target and is positioned at a second angle with respect to the second electron beam. The second angle is different from the first angle. The system according to any one of claims 1 to 7.

9. The target, A first electron source configured to generate a first electron beam guided toward a first region of the target at a first angle perpendicular to the longitudinal axis of the target, A second electron source configured to generate a second electron beam guided toward a second region of the target at a second angle oblique to the longitudinal axis of the target, The system comprises a third electron source configured to generate a third electron beam that is guided toward the second region of the target at a third angle oblique to the longitudinal axis of the target, At least one of the second electron source or the third electron source is larger or smaller than the first electron source. X-ray system.

10. Furthermore, it is equipped with a focusing electrode, The first electron source is configured to generate the first electron beam which is directed toward the target located outside the focusing electrode. The second electron source and the third electron source are configured to generate the second electron beam and the third electron beam, which are guided toward the target through the focusing electrode. The X-ray system according to claim 9.

11. The first electron source is configured to operate at a first maximum current, The second electron source and the third electron source are configured to operate with a second maximum current different from the first maximum current. The X-ray system according to claim 9 or 10.

12. The first region includes a first plane that is inclined at a first angle with respect to the first electron beam and is parallel to the longitudinal axis of the target, The second region includes a second plane that is inclined at a second angle with respect to the second electron beam and the third electron beam, and is parallel to the longitudinal axis of the target, The second angle is different from the first angle. The X-ray system according to any one of claims 9 to 11.

13. The X-ray system according to any one of claims 9 to 12, wherein the first material of the target in the first region is different from the second material of the target in the second region.

14. The first electron source includes a first type electron emitter, The second electron source and the third electron source include a second type electron emitter that is different from the first type electron emitter. The X-ray system according to any one of claims 9 to 13.

15. The first electron source is configured to guide the first electron beam toward a first focusing spot on the target having a first area, The second electron source is configured to guide the second electron beam toward a second focal spot on the target having a second area, The first area is different from the second area. The X-ray system according to any one of claims 9 to 14.

16. A target comprising a first region having a first inclination with respect to the longitudinal axis of the target and a second region having a second inclination different from the first inclination with respect to the longitudinal axis, A first electron source configured to generate a first electron beam at a first focused spot within the first region having a first area on the target, The second electron source is configured to generate a second electron beam at a second focal spot within a second region having a second area on the target, wherein the second area is larger or smaller than the first area, and the second region is spatially separated from the first region without overlapping. The first inclination is tilted at a first angle with respect to the first axis of the first electron beam, The second inclination is tilted at a second angle with respect to the second axis of the second electron beam, The second angle is closer to 90° than the first angle. X-ray source.

17. The X-ray source according to claim 16, wherein the first material in the first region is different from the second material in the second region.

18. The X-ray source according to claim 16 or 17, wherein the second electron source and the second area are each larger than the first electron source and the first area.

19. The X-ray source according to any one of claims 16 to 18, wherein the second electron source is configured to generate the second electron beam having a lower maximum current than the first electron beam, and the second area is smaller than the first area.

20. The X-ray source according to any one of claims 16 to 19, wherein the second area is larger than the first area.

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