Hybrid multi-source X-ray source and imaging system

Abstract

Some embodiments include a system having multiple 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, where a first one of the x-ray sources is different from a second one of the x-ray sources, and the target of the x-ray source is a portion of the linear target.

Description

[Background technology]

[0001] Stationary tomosynthesis can be performed using a multi-source x-ray tube, which may include multiple emitters, such as nanotube emitters. While tomosynthesis can be performed using a multi-source x-ray tube, the dose may be insufficient to perform certain higher-dose two-dimensional (2D) imaging. [Brief explanation of the drawings]

[0002] [Figure 1] FIG. 1 is a block diagram of a system with multiple x-ray sources, according to some embodiments. [Figure 2] FIG. 10 is a block diagram of a system with multiple x-ray sources, according to some other embodiments. [Figure 3A] FIG. 10 is a block diagram of a system with an x-ray source including multiple emitters, according to some other embodiments. [Figure 3B] FIG. 10 is a block diagram of a system with an x-ray source including multiple emitters, according to some other embodiments. [Figure 4] FIG. 1 is a block diagram of a system with an x-ray source including a smaller emitter, according to some embodiments. [Figure 5] FIG. 1 is a block diagram of a system with an x-ray source including a larger emitter, according to some embodiments. [Figure 6A] FIG. 1 is a block diagram of a system with an x-ray source whose target has multiple regions, according to some embodiments. [Figure 6B] FIG. 10 is a block diagram of regions of a target with different tilts, according to some embodiments. [Figure 7] FIG. 1 is a block diagram of a system with an x-ray source having a target with multiple regions, including different cooling systems, according to some embodiments. [Figure 8] FIG. 1 is a block diagram of a system with an x-ray source including multiple vacuum enclosures, according to some embodiments. [Figure 9] FIG. 1 is a block diagram of an imaging system, according to some embodiments. [Figure 10] FIG. 10 is a block diagram of an imaging system according to some other embodiments. [Figure 11] 1 is a flowchart of a technique for operating a system with multiple x-ray sources, according to some embodiments. [Figure 12] FIG. 1 is a block diagram of a system with multiple x-ray sources, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0003] Some embodiments relate to x-ray sources with multiple x-ray fluxes (representing different doses). The embodiments described herein may enable tomosynthesis to be used in lower-dose three-dimensional (3D) imaging (e.g., "3D" mammography) and higher-dose two-dimensional (2D) imaging and / or magnification imaging. Various electron emitter-anode configurations can be used with x-ray sources of different x-ray fluxes suitable for different applications.

[0004] 1 is a block diagram of a system with multiple x-ray sources, according to some embodiments. System 100a includes multiple x-ray sources 101a having emitters 102 and 104 and a target 106. System 100a may include other components, electronics, vacuum enclosures, etc., which are not shown for clarity.

[0005] Emitters 102 and 104 may be any of a variety of emitters. For example, each of emitters 102 and 104 may include a filament (e.g., a coil filament emitter), a low work function (LWF) emitter, a field emitter, a dispenser cathode, a photoemitter, etc. 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 an incident electron beam, such as electron beams 108 and 110. Target 106 can 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 such that 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 impinge on different sections or portions of target 106. In some embodiments, the electron beams 108 and 110 from the emitters 102 and 104 may strike at least 3, 5, or 10 different sections or portions of the target 106 .

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

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

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

[0010] The maximum current is the maximum current achievable by the configuration of the individual emitter 102 or 104 and the corresponding portion of the target 106. In some embodiments, the emitters 102 and 104 can be operated to have the same operating current, but the emitters 102 and 104 and / or the target 106 can be configured such that the maximum current achievable by the emitter 104 and the target 106 can be different. For example, one or more of the emitters 102 may have a maximum current that cannot be achieved by the configuration of the emitter 104, or the 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 described in more detail below, emitters 102 and 104 may have some similarities, but in operation and with a corresponding focal spot and portion of target 106, the emitter and target combination has the highest current.

[0012] In some embodiments, the maximum current through emitter 104 and the corresponding portion of target 106 is greater than the maximum current through a single emitter 102, such as emitter 102-1, and the corresponding portion of target 106. In other embodiments, the relative maximum currents are reversed, so that emitter 102 has a greater maximum current than emitter 104. The maximum currents may be related by a factor of 1.5, 2, 10, 100, or more.

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

[0014] System 100a may include any number of emitters 102, represented as emitters 102-1 through 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, the emitters 102 and 104 may be arranged in a flat, one-dimensional array. In other embodiments, the 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, the emitters 102 and 104 may be arranged in a two-dimensional array or a combination of one-dimensional and two-dimensional arrays. In some embodiments, the arc of the emitters may extend from about + / - 15 degrees to about + / - 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, the emitter 104 is located at the center of the emitter 102. However, in other embodiments, the emitter 104 may be located at a different location. For example, the emitter 104 may be located at the end of the array of emitters 104, offset from the center of the emitters 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 each operate to generate substantially the same current on target 106. Such an application may be used to generate tomographic images. However, in other operations, such as two-dimensional mammography, two-dimensional projection images may be desired. For such images, a higher x-ray intensity may be desirable. Because emitter 104 is configured differently from emitter 102, system 100a may 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 x-ray source 101b-0 with multiple emitters 104 (other x-ray sources 101 similar to x-ray sources 101a-1 through 101a-n are not shown in this 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, electron beams 110 may be focused and / or steered onto the same portion of target 106, such as onto the same focal spot on target 106. Focusing and / or steering of the electron beam 110 onto the same portion of the target 106 may be performed by structural features of the emitter 104 (e.g., emitter cavity) and / or electrical features (e.g., focusing electrodes) 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 due to the different emitter 104-2.

[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 produce a smaller focal spot on target 106, and emitter 104-2 may be larger and / or configured to produce a larger focal spot on the target. In some operations, emitter 104-1 with the smaller focal spot may be used for high-resolution imaging, while larger emitter 104-2 may be used for two-dimensional imaging such as mammography.

[0021] 3A-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, emitter 104 of x-ray source 101c-0 may include one or more focusing electrodes 112 configured to focus electron beam 110 to different focal spots on target 106. In some operations, focusing electrodes 112 may be controlled to focus each of electron beams 110 to different focal spots on target 106, as shown in FIG. 3A.

[0022] However, in other operations, as shown in FIG. 3B, the focusing electrodes 112 can be controlled to focus the electron beam 110 into a single focal spot. As a result, the effective maximum current at that focal spot is higher than that of a single emitter 104. While 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 a 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 to 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 to a single focal spot. During operation, any number of emitters 104, from zero to all emitters 104, can be controlled to selectively emit the electron beam 110, such as by the focusing electrodes 112 (this combination can be referred to as a grid) or other components specific to the type of emitter 104. As a result, by controlling which emitters 104 emit the electron beam 110 toward a single focal spot, the effective current on the single focal spot can be controlled.

[0024] 4 is a block diagram of a system with an x-ray source including a smaller emitter, according to some 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 electron beam 110d with a lower maximum current. In some embodiments, electron beam 110d may have a smaller focal spot size. The 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] 5 is a block diagram of a system with an x-ray source including a larger emitter, according to some 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 greater current may enable two-dimensional imaging, such as two-dimensional mammography.

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

[0027] 6A is a block diagram of a system including an x-ray source with a target having multiple regions, according to some 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 similar to emitter 102 of x-ray source 101f-1. Emitter 102 and emitter 104 are each configured to emit a corresponding electron beam 108 or 110 toward a different region of target 106f, identified here as regions 106f-0 through 106f-n. Regions 106f-0 through 106f-n are portions of x-ray sources 101f-0 through 101f-n. Here, emitters 102-1 to 102-n are configured to emit electron beams 108-1 to 108-n toward corresponding regions 106f-1 to 106f-n, and emitter 104 is configured to emit electron beam 110 toward region 106f-0.

[0028] Although regions 106f-0 through 106f-n are shown as adjacent, in some embodiments the spacing between the regions may vary. Additionally, in some embodiments, the focal spots produced by electron beams 108 or 110 may be separated rather than overlapping.

[0029] FIG. 6B is a block diagram of regions of a target having different slopes, according to some embodiments. Referring to FIGS. 6A and 6B, in some embodiments, region 106f-0 may have a different slope than another region, such as region 106f-1. In this example, region 106f-0 has a shallower slope than region 106f-1. As a result, the effective current density on the target in region 106f-0 is lower than that in region 106f-1, even though the currents in the corresponding electron beams 108-1 and 110 are the same. In some embodiments, the current in electron beam 110 from emitter 104 may be relatively higher compared to electron beam 108-1. The higher current may be due to the 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 the slope of region 106f-1, the focal spot size of x-ray beam 114-0 may be smaller than the focal spot size of x-ray beam 114-1. As a result, in some embodiments, a higher current may be used to generate x-ray beam 114-0 while maintaining a similar x-ray focal spot size to x-ray beam 114-1. Furthermore, a higher current of electron beam 110 may spread over a larger area within region 106f-0 of target 106. As a result, in some embodiments, the current on region 106f-0 may spread over a larger area, which may result in a smaller current density on region 106f-0 than if a larger current were focused into a smaller focal spot. A lower current density on region 106f-0 may increase the stability of target 106, for example, by reducing the temperature, heat flux, etc. of target 106. In some embodiments, the configuration of regions 106f-1 to 106f-n may be similar, but the configuration of region 106f-0 differs from the configuration of each of regions 106f-1 to 106f-n.

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

[0031] 6A, in some embodiments, region 106f-0 can include a different material than regions 106f-1 through 106f-n. As discussed above, a variety of different materials may be used for target 106f, or a variety of different materials suitable for more efficient heat transfer, such as copper (Cu), can be used to support the target. Any of these materials can be used to create a difference in material between regions 106f.

[0032] In a particular example, region 106f-0 may be formed of tungsten (W). Regions 106f-1 through 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 the other regions 106f-1 through 106f-n. Therefore, a material with higher thermal performance, such as tungsten, may be used for region 106f-0, e.g., a higher melting point. However, rhodium (Rh) may have a more desirable x-ray spectrum for certain applications, such as mammography. Therefore, rhodium may be used for the portions of regions 106f-1 through 106f-n that do not receive the electron beam 108 with a high maximum current. Thus, in some embodiments, materials may be selected based on thermal performance and / or x-ray emission spectrum.

[0033] FIG. 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 some embodiments. System 100g may be similar to system 100f described above. However, system 100g may include a cooling system 116g proximate region 106f-1 and configured to cool at least 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 portions of target 106f may be cooled. However, additional cooling may be provided for region 106f-0 because the region 106f-0 may generate more heat due to its higher maximum current.

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

[0035] In some embodiments, the ability to have two different configurations within one system 100, such as x-ray sources 100a-100g, may reduce costs. Whether the desired operation requires a higher or lower maximum current, the combination in a single system 100 may reduce complexity, include more uniform components, reduce costs, and so on. Furthermore, this combination may enable additional uses while preserving previous uses of other x-ray sources. For example, a user accustomed to using a particular x-ray source for two-dimensional imaging may continue to use that operation while gaining the additional benefits noted above, such as tomographic imaging, improved image quality due to reduced motion blur, and higher resolution imaging.

[0036] FIG. 8 is a block diagram of a system with an x-ray source including multiple vacuum enclosures, according to some embodiments. In some embodiments, system 100h may be similar to system 100a described above. However, emitter 104 may be in a different vacuum enclosure 120. Here, emitter 102 is disposed in vacuum enclosure 120-1 along with corresponding target 106h-1. However, emitter 104 is disposed in vacuum enclosure 120-2 along with corresponding target 106h-2. Vacuum enclosure 120-1 may be adjacent to vacuum enclosure 120-2 and positioned so that the resulting x-rays are directed toward substantially the same location. Including emitter 104 in a vacuum enclosure 120-2 different from vacuum enclosure 120-1 containing emitter 102 can reduce costs by allowing for replacement of failed and / or worn portions 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 the target than the second x-ray source. The first x-ray sources may share the same control electronics, power supply, etc.

[0038] In some embodiments, the target is part of a stationary anode. In some embodiments, the target is part of a linear anode.

[0039] FIG. 9 is a block diagram of an imaging system, according to some 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 in the vacuum enclosure. In some embodiments, the configuration of the electron source 205 and the target 206 may be similar to the x-ray source 100 described above, although in other embodiments, the combination may be different. For example, the electron source 205 may include a single emitter.

[0040] Collimator 220a is configured to shape x-ray beam 270. Shaped x-ray beam 270 includes a central axis 272, a portion 274 near electron source 205, and a portion 276 far from electron source 205. Central axis 272 is the direction of x-rays in x-ray beam 270 that originate at an angle perpendicular to incident electron beam 210. Portions 274 and 276 are at least partially formed by edges 220a-1 and 220a-2 of collimator 220a. In particular, edge 220a-1 is closer to electron source 205 than central axis 272. Edge 220a-2 is farther from electron source 205 than central axis 272. Due to a heel effect during generation of 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 near edge 220a-2 of collimator 220a.

[0041] The anode heel effect, or heel effect, refers to the reduction in electric field strength or x-ray flux in portions of the x-ray beam 270 closer to the anode compared to the cathode or electron source 205 due to less x-ray emission from the target material at angles greater than perpendicular to the electron beam. Conversion of the electron beam 210 to x-rays occurs not only at the surface of the target 206 material, but also within the target 206 material. Because x-rays are generated deeper within the target 206 material, these x-rays exit and traverse the target 206 material, allowing the x-rays to travel to the detector 230. More target 206 material must be traversed at an emission angle perpendicular to the electron beam 210 (closer to the target 206) than at an emission angle more parallel to the electron beam 210 (closer to the cathode or electron source 205). As the target 206 material increases, there is more reabsorption of x-rays by the target 206 material, resulting in fewer x-rays reaching the electric field at angles perpendicular to the electron beam 210. In contrast, x-rays emitted at angles closer to the incident electron beam 210 penetrate less of the target 206 material and are less reabsorbed. The net result is that the electric field strength and x-ray flux directed toward the cathode or electron source 205 is greater than that directed toward the target 206. This non-uniform beam effect, or heel effect, can adversely affect the detection results of x-ray imaging.

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

[0043] In some embodiments, x-ray source 200a is used in conjunction with detector 230 to generate an image based on portion 240 of patient 250. For example, portion 240 may be the breast of patient 250. Due to the positioning of patient 250 relative to x-ray beam 270, portion 240' may not be imaged. However, the remainder may be imaged with an x-ray beam that is less susceptible to intensity variations due to the heel effect (e.g., the heel effect applies to narrower portions of the breast with lower mass density). For example, the heel effect variations may range from 80% to 100% for a 15-degree angle of surface 206a. Thus, for a given image quality during operation of x-ray source 200a, the patient may receive a reduced dose. Furthermore, the ability to use a substantially imaging x-ray beam 270 may reduce the source-to-image distance (SID), increasing the imaging x-ray dose, reducing power for the same imaging x-ray dose, etc.

[0044] In some embodiments, a smaller angle may be used on the surface 206a of the target 206. For example, if a nanotube (NT) emitter has a size of w1 (width) × l1 (length), the electrical focal 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). The x-ray FSS of w3 (width) × l3 (length) is determined by the electron FSS and the angle (θ) of the surface 206a. w3 is equal to w2, and l3 is equal to l2 × sin(θ). For a given x-ray FSS, a smaller anode angle results in a larger electron FSS, allowing for a larger emitter. A larger NT emitter can generate a higher emission current. The larger the electron FSS on surface 206a, the larger the area over which to distribute the heat load, allowing for higher tube power and x-ray dose output.

[0045] Therefore, if the influence of the heel effect is reduced, a smaller angle can be used for surface 206a. A smaller angle allows for a larger current or larger size of the emitter in electron source 205. For example, a larger field emitter size may provide a higher current, but the larger size increases the x-ray FSS. However, for the same or similar SID, the dose can be increased despite lowering the angle of surface 206a to maintain the x-ray FSS.

[0046] FIG. 10 is a block diagram of an imaging system according to some 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 located in a different position, such as closer to the electron source 205. As a result of the positions of the edges 220b-1 and 220b-2 of the collimator 220b, the portion of the x-ray beam 270 that exits the collimator is substantially only the portion 274 or a subset of the portion 274. The heel effect can be mitigated against the 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 the portion 274 may be sufficient, allowing the x-ray filter 260 to be omitted. For example, the x-ray intensity may vary from about 90% to 100% at a 15 degree angle on the target surface 206a. Additionally, the imaging system 200b may have a higher intensity at the distal end of the portion 240.

[0047] In some embodiments, imaging system 200b allows patient 250 to be located on the opposite side of system 200b from that shown in FIG. 9. In some embodiments, the use of a distributed electron source 205 as described above may allow additional space for patient 250 compared to an electron source 205 using a rotating anode. The number of external accessories on the patient 250 side of system 200b can be reduced, leaving more space for patient 250. For example, high-voltage connections, ion pumps, getters, tube formation, etc., may leave more space for patient 250. Furthermore, the use of a distributed electron source 205 allows 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. Patient 250 can be positioned close to x-ray beam 270, minimizing the amount of the patient's 250 chest wall being clipped from the image.

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

[0049] FIG. 11 is a flowchart of a technique for operating a system with multiple x-ray sources, according to some embodiments. At 1100, a first x-ray beam is emitted from a first x-ray source. At 1102, a second x-ray beam is emitted from a second x-ray source. This technique and variations thereof can be used with the various systems described above. For example, with reference to FIGS. 1 and 11, emission of the first x-ray beam can be performed by x-ray source 101a-0, and emission of the second x-ray beam can be performed by x-ray source 101a-1. The emission of the x-ray beams can be caused by the emission of electron beams 108 and 110 from corresponding emitters 102 and 104.

[0050] 2 and 11, the emission of one of the x-ray beams may be the result of multiple electron beams 110-1 and 110-2 focusing on target 106. Referring to Figures 3A, 3B, and 11, in some embodiments, the focusing can be altered so that electron beams 110-1 and 110-2 each focus on different areas or the same area of ​​target 106 to generate multiple or single x-ray beams.

[0051] FIG. 12 is a block diagram of a system with multiple x-ray sources, according to some embodiments. In some embodiments, x-ray source 101 may be coupled to control logic 1200. 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, a combination of such devices, or the like. Control logic 1200 may include external interfaces, such as an address and data bus interface, an interrupt interface, or the like. Control logic 1200 may also include other interface devices, such as a logic chipset, a hub, a memory controller, a communication interface, or the like, for connecting control logic 1200 to internal and external components. Control logic 1200 may be configured to control various operations described herein. Control logic 1200 may include connections to x-ray source 101, including connections for applying voltage and / or supplying current to emitters 102 and 104, focusing electrode 112, target 106, or the like.

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

[0053] Some embodiments include a system having multiple 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, and a first x-ray source (101) of the x-ray sources (101) is different from a 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 a 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 or more.

[0056] In some embodiments, the linear target (106) is a flat, curved, or piecewise 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, a first x-ray source of the plurality of x-ray sources (101) includes at least one field emitter, and another x-ray source (101) of 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 beam from each of the x-ray sources (101).

[0060] In some embodiments, a first x-ray source (101) of the x-ray sources (101) includes a first electron source (102, 104) having at least one emitter, and a 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 a first maximum current of a first electron beam (108, 110) from one of the emitters of the first electron source (102, 104) at a first focal spot on a corresponding target (106) is different from a second maximum current of a second electron beam (108, 110) from the second electron source (102, 104) at a 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 times, 10 times, and 100 times.

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

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

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

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

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

[0069] In some embodiments, for 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 a 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, a second edge of the collimator (220) opposite the first edge is at the electron source (102, 104) or closer to the electron source (102, 104) than the central axis (272) of the x-ray beam 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 than 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 tilt 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) has a material that is different from the material of 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 than the target (106) of the second x-ray source (101).

[0076] Some embodiments include a method, the method including 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 the target (106), the first x-ray source (101) being different from the second x-ray source (101).

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

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

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

[0080] In some embodiments, at least one emitter of the secondary electron source (102, 104) includes a first emitter and a second emitter, and the method further includes emitting a second electron beam (108, 110) from the first emitter of the secondary electron source (102, 104) at a first current during a first operation, and emitting a second electron beam (108, 110) from the second emitter of the secondary electron source (102, 104) at 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) comprises multiple emitters, and further includes focusing the electron beams (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 less 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 a collimator (220) such that the collimator (220) passes at least a portion of the x-ray beam between an edge of the collimator (220) and a central axis (272) of the x-ray beam proximate the second electron source (102, 104).

[0085] Some embodiments include a system having multiple means for emitting an electron beam and a means for generating x-rays in response to the electron beam, where 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. Examples of means for emitting an electron beam include electron sources 102 and 104. Examples of means for generating x-rays in response to the electron beam include target 106.

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

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

[0088] Some embodiments comprise a system including an electron source (102, 104) having multiple emitters, a target (106), the emitters of the electron source (102, 104) configured to emit electrons toward multiple focal spots on separate regions of the target (106), at least one of the separate regions of the target (106) having a different configuration than at least one other of the separate regions.

[0089] Some embodiments comprise a system including 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 of the emitters 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 a first maximum current of a 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 a second maximum current of a 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 have been described in accordance with specific embodiments, those skilled in the art will readily recognize that many variations to the specific embodiments are possible, and therefore, any variations should be considered within the spirit and scope of the disclosure herein. Accordingly, many modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

[0091] The claims following this written disclosure are hereby expressly incorporated into this disclosure, with each claim standing on its own as a separate embodiment. This disclosure includes all variations of independent claims accompanied by dependent claims. Additionally, additional embodiments that may be derived from the following independent and dependent claims are also expressly incorporated into this description. 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 bracketed term "[x]" is replaced with the number of the most recently recited independent claim. For example, for a first set of claims beginning with independent claim 1, claim 4 depends on either claim 1 or 3, and these separate dependencies can result in two different embodiments; claim 5 depends on any one of claims 1, 3, or 4, and these separate dependencies can result in three different embodiments; claim 6 depends on any one of claims 1, 3, 4, or 5, and these separate dependencies can result in four different embodiments, and so on.

[0092] The recitation in a claim of the term "first" with respect to a feature or element does not necessarily imply the existence of second or additional such features or elements. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: (Other possible items) (Item 1) 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; Including, a first x-ray source of the x-ray sources is different from a second x-ray source of the x-ray sources; The system wherein the target of the x-ray source is part of a linear target. (Item 2) Item 10. The system of item 1, wherein the linear target has an aspect ratio of at least one of 2:1, 10:1, and 20:1. (Item 3) 3. The system of claim 1 or 2, wherein the x-ray source is positioned such that the corresponding x-ray beam is substantially focused to a single point. (Item 4) a first x-ray source of the plurality of x-ray sources includes at least one field emitter; 4. The system of any one of items 1 to 3, wherein another of the x-ray sources comprises a filament, a low work function emitter, a dispenser cathode, or a photoemitter. (Item 5) the first x-ray source of the x-ray sources includes a first electron source having at least one emitter; the second one of the x-ray sources includes a second electron source having at least one emitter; 5. The system of claim 1, wherein the first electron source and the second electron source are configured such that a first maximum current of a first electron beam from one of the emitters of the first electron source at a first focal spot on a corresponding target is different from a second maximum current of a second electron beam from the second electron source at a second focal spot on the corresponding target. (Item 6) Item 6. The system of item 5, wherein the first maximum current is greater than the second maximum current by at least one of 2 times, 10 times, or 100 times. (Item 7) at least some of the x-ray sources are substantially identical; or 7. The system of any one of items 1 to 6, wherein at least three of the x-ray sources are substantially the same. (Item 8) the first x-ray source includes a first emitter and a second emitter; 8. The system of any one of claims 1 to 7, wherein the first emitter is configured to generate a maximum current that is higher than a maximum current of the second emitter. (Item 9) The first x-ray source a plurality of emitters, and a plurality of 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; 9. The system of any one of items 1 to 8, comprising: (Item 10) a first vacuum enclosure having the first x-ray source; a second evacuated enclosure separate from the first evacuated enclosure, the second evacuated enclosure having the second x-ray source; 10. The system of any one of items 1 to 9, further comprising: (Item 11) For at least one of the x-ray sources: a surface of the target positioned at an angle other than normal to an associated electron beam; 11. The system of any one of items 1 to 10, wherein a first edge of the collimator closest to the electron source is closer to the electron source than a central axis of the x-ray beam before it enters the collimator. (Item 12) Item 12. The system of item 11, wherein a second edge of the collimator opposite the first edge is at the electron source or closer to the electron source than the central axis of the x-ray beam before entering the collimator. (Item 13) the target of the first x-ray source has a different tilt than the target of the second x-ray source; and / or 12. The system of any one of items 1 to 11, wherein the target of the first x-ray source has a material that is different from a material of the target of the second x-ray source. (Item 14) 14. The system of any one of claims 1 to 13, further comprising a cooling system configured to cool the target of the first x-ray source differently than 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 target; A method comprising: the first x-ray source is different from the second x-ray source; The method wherein the target is a linear target. (Item 16) emitting the first x-ray beam includes emitting a first electron beam toward the target from a first electron source including 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; Item 16. The method of item 15, wherein a first maximum current of the first electron beam at a first focal spot on the target is different from a second maximum current of the second electron beam at a 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; emitting the second electron beam at a first current from the first emitter of the second electron source during a first operation; and emitting the second electron beam from the second emitter of the second electron source at a second current higher than the first current during a second operation; Item 17. The method of item 16, further comprising: (Item 18) the at least one emitter of the second electron source includes a plurality of emitters; 18. The method of claim 16, further comprising focusing an electron beam from the emitter of the second electron source onto the second focal spot. (Item 19) a plurality of means for emitting electron beams; means for generating x-rays in response to said electron beam; A system comprising: 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) 20. The system of claim 19, wherein a first maximum current at the means for generating x-rays of a first electron beam from one of the means for emitting an electron beam is different from a second maximum current at a second electron beam from another one of the means for emitting an electron beam.

Claims

1. 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; Including, a first one of the x-ray sources is different from a second one of the x-ray sources, and the electron source of the first x-ray source includes at least one field emitter; the electron source of the second one of the x-ray sources is different from a field emitter; the targets of the x-ray source are portions of a linear target, each target being positioned at a different location along the linear target; the electron source of the first x-ray source, the electron source of the second x-ray source, and the target are configured such that a first maximum achievable current of the electron beam from the electron source of the first x-ray source at a first focal spot on the corresponding target is different from a second maximum achievable current of the electron beam from the electron source of the second x-ray source at a second focal spot on the corresponding target.

2. The system of claim 1 , wherein the first maximum achievable current is greater than the second maximum achievable current by at least one of two times, ten times, or one hundred times.

3. For at least one of the plurality of x-ray sources, a surface of the target is positioned at an angle other than perpendicular to an associated electron beam; the system includes a collimator downstream of the target that initially shapes the x-ray beam, a first edge of the collimator closest to the electron source being closer to the electron source than a central axis of the x-ray beam before it enters the collimator; The system of claim 1 .

4. 4. The system of claim 3, wherein a second edge of the collimator opposite the first edge is at the central axis of the x-ray beam before entering the collimator or is closer to the electron source than the central axis of the x-ray beam before entering the collimator.

5. The system of claim 1 , wherein the aspect ratio of the linear target is greater than or equal to 2:1, 10:1, or 20:

1.

6. The system of claim 1 , wherein the second one of the x-ray sources comprises a filament, a low work function emitter, a dispenser cathode, or a photoemitter.

7. at least some of the x-ray sources are substantially identical; or The system of claim 1 , wherein at least three of the x-ray sources are substantially identical.

8. the first x-ray source includes a first emitter and a second emitter; 5. The system of claim 1, wherein the first emitter is configured to generate a maximum current that is higher than a maximum current of the second emitter.

9. The first x-ray source a plurality of emitters, and a plurality of 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; The system of claim 1 , comprising:

10. a first evacuated enclosure having the first x-ray source; a second evacuated enclosure separate from the first evacuated enclosure having the second x-ray source; The system of claim 1 , further comprising:

11. A system described in any one of claims 1 to 4, wherein the target of the first x-ray source has a different inclination than the target of the second x-ray source.

12. A system described in any one of claims 1 to 4, wherein the target of the first x-ray source has a material different from the material of the target of the second x-ray source.

13. 5. The system of claim 1, further comprising a cooling system configured to cool the target of the first x-ray source differently than the target of the second x-ray source.

14. emitting a first x-ray beam from a first x-ray source including a field emitter at a first portion of the target; and emitting a second x-ray beam from a second x-ray source including an emitter different from the field emitter at a second portion of the target different from the first portion of the target; A method comprising: the first x-ray source is different from the second x-ray source; the target is a linear target; the field emitter of the first x-ray source, the emitter of the second x-ray source, and the target are configured such that a first maximum achievable current of a first electron beam emitted from the field emitter of the first x-ray source on the first portion of the target is different from a second maximum achievable current of a second electron beam emitted from the emitter of the second x-ray source on the second portion of the target.

15. emitting the first x-ray beam includes emitting the first electron beam toward the target from a first electron source including a plurality of emitters; emitting the second x-ray beam includes emitting the second electron beam toward the target from a second electron source including at least one emitter; 15. The method of claim 14, wherein the first maximum achievable current of the first electron beam at a first focal spot on the target is different from the second maximum achievable current of the second electron beam at a second focal spot on the target.

16. the at least one emitter of the second electron source includes a first emitter and a second emitter; emitting the second electron beam at a first current from the first emitter of the second electron source during a first operation; and emitting the second electron beam from the second emitter of the second electron source at a second current higher than the first current during a second operation; 16. The method of claim 15, further comprising:

17. the at least one emitter of the second electron source includes a plurality of emitters; 17. The method of claim 15 or 16, further comprising focusing an electron beam from the emitter of the second electron source onto the second focal spot.

18. a plurality of means for emitting electron beams; means for generating x-rays in response to said electron beam; A system comprising: a first combination of first means for emitting an electron beam and means for generating x-rays in response to the electron beam of the first means for emitting an electron beam includes a field emitter, and the first combination is different from a second combination of second means for emitting an electron beam and means for generating x-rays in response to the electron beam of the second means for emitting an electron beam; the second means for emitting an electron beam includes an emitter different from a field emitter; the means for generating x-rays in response to the electron beam of the first means for emitting an electron beam is located at a different location than the means for generating x-rays in response to the electron beam of the second means for emitting an electron beam; a first maximum achievable current at the means for generating x-rays in response to the electron beam of the first means for emitting the electron beam is different from a second maximum achievable current at the means for generating x-rays in response to the electron beam of the second means for emitting the electron beam.

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