Hybrid multi-source X-ray source and imaging system

Abstract

Some embodiments include a system comprising: a plurality of x-ray sources, each x-ray source comprising: 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: a first x-ray source in the x-ray sources is different from a second x-ray source in the x-ray sources; and the target of the x-ray source is part of a linear target.

Description

[0001] Fixed tomosynthesis can be performed using a multi-source x-ray tube. Such a multi-source x-ray tube may include multiple emitters, such as nanotube emitters. Although tomosynthesis can be performed using a multi-source x-ray tube, the dose may not be sufficient to perform certain higher dose two-dimensional (2D) imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a block diagram of a system with multiple x-ray sources, according to some embodiments.

[0003] Figure 2 is a block diagram of a system with multiple x-ray sources according to some other embodiments.

[0004] FIG. 3A to FIG. 3B is a block diagram of a system including an x-ray source with multiple emitters, according to some other embodiments.

[0005] Figure 4 is a block diagram of a system having an x-ray source with a smaller emitter, according to some embodiments.

[0006] Figure 5 is a block diagram of a system having an x-ray source including a larger emitter, according to some embodiments.

[0007] Fig. 6A is a block diagram of a system having an x-ray source including a target having multiple regions, according to some embodiments.

[0008] Figure 6B is a block diagram of regions of a target having different slopes, according to some embodiments.

[0009] Figure 7 is a block diagram of a system having an x-ray source with a target having multiple regions with different cooling systems, according to some embodiments.

[0010] Figure 8 is a block diagram of a system having an x-ray source including multiple vacuum enclosures, according to some embodiments.

[0011] Fig. 9 is a block diagram of an imaging system according to some embodiments.

[0012] Fig.10 is a block diagram of an imaging system according to some other embodiments.

[0013] Fig.11 is a flow chart of a technique for operating a system with multiple x-ray sources, according to some embodiments.

[0014] Fig.12is a block diagram of a system with multiple x-ray sources, according to some embodiments. DETAILED DESCRIPTION

[0015] Some embodiments are directed to x-ray sources having multiple x-ray fluxes (representing different doses). Embodiments described herein may allow the use of tomosynthesis in lower dose three-dimensional (3D) imaging (e.g., "3D" mammography), as well as in one or both of higher dose two-dimensional (2D) imaging and magnified imaging. Different electron emitter-anode configurations may be used for x-ray sources having different x-ray fluxes suitable for different applications.

[0016] Figure 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, which include emitters 102 and 104 and target 106. System 100a may include other components, electronics, vacuum housings, etc.; however, for clarity, those components are not shown.

[0017] Emitters 102 and 104 may be any type of emitter. 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 reserve cathode, a photoemitter, etc. Emitters 102 and 104 may be the same or different types of emitters. For example, emitter 102 may be a field emitter used in tomosynthesis, while emitter 104 may be a filament used in 2D and / or magnified imaging.

[0018] 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 may include materials such as tungsten (W), molybdenum (Mo), rhodium (Rh), silver (Ag), rhenium (Re), palladium (Pd), etc. In some embodiments, target 106 is a linear target having a length:width (or length:height) aspect ratio, wherein the target length is 2 times, 5 times, 10 times, 20 times, or 50 times the target width (or height). In some embodiments, the linear target may be flat or curved, such as a continuous curve, a piecewise linear curve, a combination of such curves, etc. In some embodiments, the electron beams 108 and 110 from each of emitters 102 and 104 may strike different sections or portions of target 106. In some embodiments, the electron beams 108 and 110 from emitters 102 and 104 may strike at least three, five, or ten different sections or portions of target 106.

[0019] 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 can be oriented in 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 can be the location where an object, specimen, patient, etc. is placed. In some embodiments, the system can be mounted on a fixed structure or gantry. The placement and orientation of the x-ray source 101 can alleviate the need to rotate the system around an object, specimen, patient, etc.

[0020] The combination of the emitter 102 or 104 and the target 106 forms the x-ray source 101a. For example, the x-ray source 101a-0 includes the emitter 104 and the target 106. The x-ray sources 101a-1 to 101a-n each include a corresponding emitter 102-1 to 102-n and a target 106. Although a single target 106 has been shown as an example, as will be described in further detail below, each x-ray source 101 may include a different region of the target 106 or a separate target 106. As will be described in further detail below, the x-ray source 101 may have other aspects, such as a different configuration of the emitter 102 or 104, a different target 106, and / or a different region of the target 106, etc., so that at least one of the x-ray sources 101 is different from the other of the x-ray sources 101. Here, the x-ray source 101a-0 is different from the x-ray sources 101a-1 to 101a-n in that the emitter 102 is different from the 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) is different from the other x-ray sources. However, in some embodiments, each of x-ray sources 101 may be different. In other embodiments, different combinations of emitters 102 and 104 may be identical, while others are different.

[0021] Although emitters 102 and 104 may be similar, emitters 102 and 104 are configured such that a maximum current of a first electron beam 108 from one of emitters 102 at a first focal point on target 106 is different than a second maximum current of a second electron beam 110 at a second focal point on target 106 .

[0022] The maximum current is the maximum current achievable by the configuration of the corresponding portion of the individual emitters 102 or 104 and the target 106. Although in some embodiments, the emitters 102 and 104 may be operated to have the same operating current, the emitters 102 and 104 and / or the target 106 may be configured such that the maximum current achievable by the emitters 104 and the target 106 may also be different. For example, one or more of the emitters 102 may have a maximum current that cannot be achieved under 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.

[0023] In some embodiments, system 100a includes at least one emitter 102 and a single emitter 104. As will be described in further detail below, emitters 102 and 104 may have some similarities; however, in operation and in combination with a corresponding focus and portion of target 106, the emitter-target combination has the maximum current.

[0024] In some embodiments, the maximum current due to emitter 104 and corresponding portions of target 106 is greater than the maximum current due to a single emitter 102 (such as emitter 102-1) and corresponding portions of target 106. In other embodiments, the relative maximum currents are reversed so that the maximum current of emitter 102 is greater than emitter 104. The maximum currents may be related by a factor of 1.5, 2, 10, 100, or more.

[0025] In some embodiments, the maximum current of the electron beam 110 may be greater than or less than the maximum current of one of the electron beams 108. Thus, the electron beam 108 may generate a different maximum current on the target 106 than the electron beam 110 even at the same portion of the target 106. 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., the first maximum current) of the electron beam (e.g., 110) from the first electron source (e.g., 101a-0) is at least two times (2 times), three times, five times, ten times, twenty times, fifty times, or one hundred times the maximum current (e.g., the second maximum current) of the electron beam (e.g., 108) from the second electron source (e.g., 101a-1). For example, the electron beam 108 from the emitter 102 may be used for lower dose tomosynthesis, while the electron beam 110 from the emitter 104 may be used for higher dose 2D and / or magnified imaging.

[0026] System 100a may include any number of transmitters 102, represented by transmitters 102-1 through 102-n, where n is any integer greater than one. In some embodiments, the number of transmitters 102 is one or at least two. In some embodiments, the number of transmitters 102 may be about 25. In other embodiments, the number may be different based on various factors such as layout, configuration, application, etc.

[0027] 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, a combination of such curves, etc. In some embodiments, the 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 emitters may extend from about + / - 15 degrees to about + / - 90 degrees around a center point. The target 106 may be shaped in a manner corresponding to the one-dimensional array or the two-dimensional array of emitters 102 and 104.

[0028] In some embodiments, the emitter 104 is disposed at the center of the emitter 102. However, in other embodiments, the emitter 104 may be disposed at a different location. For example, the emitter 104 may be disposed at one end of the array of emitters 104, disposed offset from the center of the emitter 104, etc.

[0029] In some embodiments, system 100a can be used for different applications. For example, in one set of operations, each of emitters 102 and 104 can be operated to generate substantially the same current on target 106. Such applications can be used to generate tomographic images. However, in other operations such as two-dimensional mammography, two-dimensional projection images may be required. For such images, higher x-ray intensities may be required. Since emitter 104 is configured differently from emitter 102, system 100a can be used for both types of operations.

[0030] Figure 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 having multiple emitters 104 (for clarity, other x-ray sources 101 similar to x-ray sources 101a-1 to 101a-n are not shown in this or other figures). Here, two emitters 104-1 and 104-2 are shown; however, 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 beam 110 may be focused and / or directed onto the same portion of the target 106, such as onto the same focal point on the target 106. The focusing and / or directing of the electron beam 110 on the same portion of the target 106 may be performed by the structure (e.g., emitter cavity) and / or electrical (e.g., focusing electrode) features of the emitter 104 and / or magnetic materials or electrostatic mechanisms, etc.

[0031] 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 by being larger or smaller. Therefore, the maximum current on the target may be different for different emitters 104-2.

[0032] 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, while 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 a smaller focal spot may be used for high-resolution imaging, while the larger emitter 104-2 may be used for two-dimensional imaging, such as mammography.

[0033] FIG. 3A to FIG. 3B 1 is a block diagram of a system including an x-ray source having multiple emitters according to some other embodiments. In some embodiments, system 100c can be similar to system 100b described above. However, emitter 104 of x-ray source 101c-0 can include one or more focusing electrodes 112 configured to focus electron beam 110 at different focal points on target 106. In some operations, focusing electrode 112 can be controlled to focus each of electron beam 110 at a different focal point on target 106, such as Figure 3A shown.

[0034] However, in other operations, the focusing electrode 112 may be controlled to focus the electron beam 110 on a single focal point, such as Figure 3B As shown. Therefore, the effective maximum current at this focal point will be higher than the effective maximum current of a single emitter 104. Although two emitters 104 have been used as an example, in other embodiments, more emitters 104 may be used. In some embodiments, a sufficient number of emitters 104 may be grouped together to achieve the desired total current. For example, the emitters 104 may be arranged in a two-dimensional array.

[0035] While some embodiments have been described in which the focusing electrodes 112 may be controlled to focus the electron beam 110 on a single focal point or multiple focal points on the target 106, in other embodiments, the focus may be fixed. For example, the focus may be set to focus the electron beam 110 on a single focal point. In operation, any number of emitters 104, from zero to all emitters 104, may be controlled, such as by the focusing electrodes 112 (the combination of which may be referred to as a grid) or other components specific to the type of emitter 104, to selectively emit the electron beam 110. Thus, the effective current at the single focal point may be controlled by controlling which emitters 104 emit electron beams 110 toward the single focal point.

[0036] Figure 4 is a block diagram of a system having an x-ray source including a smaller emitter according to some embodiments. System 100d can be similar to system 100a described above. However, in some embodiments, emitter 104d can be smaller than emitter 102. Emitter 104d can be configured to provide an electron beam 104d with a lower maximum current. In some embodiments, electron beam 110d can have a smaller focal spot size. The smaller focal spot size can allow for greater resolution than other electron beams 108. Therefore, electron beam 110d and the resulting x-ray beam can be used for high-resolution imaging.

[0037] Figure 5 1 is a block diagram of a system having an x-ray source including a larger emitter according to some embodiments. System 100e can be similar to system 100a described above. However, in some embodiments, the maximum current of emitter 104e can be greater than the maximum current of emitter 102. Therefore, the larger current can allow two-dimensional imaging, such as two-dimensional mammography.

[0038] A number of variations of emitter configurations have been described above that produce different maximum currents on the target 106. As will be described in further detail below, the target 106 may include different configurations for different portions of the target 106 to achieve different maximum currents. Although embodiments will be 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 configurations and target configurations.

[0039] Fig. 6A 1 is a block diagram of a system having an x-ray source including 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. Each emitter 102 and emitter 104 is configured to emit a corresponding electron beam 108 or 110 toward a different region of target 106f (identified here as regions 106f-0 to 106f-n). Regions 106f-0 to 106f-n are portions 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 corresponding regions 106f-1 to 106f-n, and emitter 104 is configured to emit electron beam 110 toward region 106f-0.

[0040] Although regions 106f-0 through 106f-n are shown as being adjacent, in some embodiments, the spacing between regions may be different. Additionally, in some embodiments, the focal spots created by electron beams 108 or 110 may be separate, rather than overlapping.

[0041] Figure 6B is a block diagram of regions of a target having different slopes according to some embodiments. Fig. 6A and Figure 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. Therefore, with the same current in the corresponding electron beams 108-1 and 110, the effective current density on the target in region 106f-0 is less than the effective current density in region 106f-1. In some embodiments, the current in the electron beam 110 from the emitter 104 may be relatively larger than the electron beam 108-1. The larger current may be attributed to the larger size of the emitter 104. Relative to region 106f-1, the electron beam 110 may have a larger focal spot on region 106f-0 of the target 106. However, because the slope of region 106f-0 is less than the slope of region 106f-1, the focal spot size of the x-ray beam 114-0 may be smaller than the focal spot size of the x-ray beam 114-1. Thus, in some embodiments, a higher current may be used to generate the x-ray beam 114-0 while maintaining a similar x-ray focal spot size as the x-ray beam 114-1. In addition, the higher current in the electron beam 110 may be distributed over a larger area in the region 106f-0 of the target 106. Thus, in some embodiments, the current on the region 106f-0 may be distributed over a larger area, resulting in a current density on the region 106f-0 that is less than the current density in the case where the larger current is focused on a smaller focal spot. The lower current density on the region 106f-0 may improve the stability of the target 106, for example, by reducing the temperature, heat flux, etc. of the target 106. In some embodiments, the configurations of the regions 106f-1 to 106f-n may be similar, while the configuration of the region 106f-0 is different from the configuration of each of the regions 106f-1 to 106f-n.

[0042] Although the shallower slope in region 106f-0 has been used as an example, in other embodiments, the configuration may be different. For example, region 106f-0 may have a steeper slope relative to regions 106f-1 through 106f-n.

[0043] Return to reference Fig. 6AIn some embodiments, region 106f-0 may include a material different from that of regions 106f-1 to 106f-n. As described above, a variety of different materials may be used as target 106f, or a variety of different materials may be used to support a target suitable for more efficient heat transfer, such as copper (Cu), for example. Any of these materials may be used to create material differences among regions 106f.

[0044] In a specific example, 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 the target 106f-0 may be greater than that of other regions 106f-1 to 106f-n. Therefore, a material (such as tungsten) with higher thermal properties (such as having a higher melting point) may be used in this region 106f-0. However, rhodium (Rh) may have a more desirable x-ray spectrum for specific applications such as mammography. Therefore, rhodium may be used as a portion of regions 106f-1 to 106f-n that will not receive an electron beam 108 with a higher maximum current. Therefore, in some embodiments, a material may be selected based on thermal properties and / or an x-ray emission spectrum.

[0045] Figure 7 1 is a block diagram of a system having an x-ray source including 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 that is proximate to region 106f-1 and is configured to cool at least region 106f-0. For example, cooling system 1006 may include a fluid cooling system such as a water cooling system, an evaporative cooling system, a phase change material, etc. In some embodiments, other portions of target 106f may be cooled. However, since region 106f-0 may generate more heat due to a higher maximum current, additional cooling may be provided to region 106f-0.

[0046] In some embodiments, the regions 106f may be spaced apart from each other. For example, the spacing between the regions 106f may be a fraction of the length of the region 106f, such as about 5%, 10% or more. In some embodiments, the spacing between the regions 106f may be the same or different. In some embodiments, the spacing between the region 106f-0 and the other regions 106f may be different from the spacing between those other regions 106f.

[0047] In some embodiments, the ability to have two different configurations (such as x-ray sources 100a-100g) in one system 100 can achieve reduced costs. Regardless of whether the desired operation is higher or lower maximum current, combining into a single system 100 can reduce complexity, including more unified parts, reduced costs, etc. In addition, the combination can allow additional uses while maintaining previous uses 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 described above, such as tomographic imaging, improved image quality due to reduced motion blur, higher resolution imaging, etc.

[0048] Figure 8 1 is a block diagram of a system having an x-ray source including multiple vacuum hoods 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 hood 120. Here, emitter 102 is disposed in vacuum hood 120-1 together with corresponding target 106h-1. However, emitter 104 is disposed in vacuum hood 120-2 together with corresponding target 106h-2. Vacuum hood 120-1 may be adjacent to vacuum hood 120-2 and be disposed so that the resulting x-rays are directed to substantially the same location. Placing emitter 104 in a vacuum hood 120-2 that is different from vacuum hood 120-1 having emitter 102 allows replacement of a portion of system 100h that fails and / or wears out without replacing the entire system 100h, which may provide cost savings.

[0049] In some embodiments, the first x-ray source strikes a different target or target area than the second x-ray source.The first x-ray sources may share the same control electronics, power supply, etc.

[0050] In some embodiments, the targets described above are part of a fixed anode. In some embodiments, the targets described above are part of a linear anode.

[0051] Fig. 9200a. The imaging system 200a 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 disposed at an angle different from vertical relative to the incident electron beam 210. In some embodiments, the target 206 is part of a rotating anode; however, in other embodiments, the target 206 may be part of a fixed anode. The electron beam 210 received by the target 206 generates an x-ray beam 270 that passes through a window 280 of a vacuum hood. 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; however, in other embodiments, the combination may be different. For example, the electron source 205 may include a single emitter.

[0052] 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 farther from the electron source 205. The central axis 272 is the direction of the x-rays generated at an angle perpendicular to the incident electron beam 210 in the x-ray beam 270. The portions 274 and 276 are at least partially formed by the edges 220a-1 and 220a-2 of the collimator 220a. In particular, the edge 220a-1 is closer to the electron source 205 than the central axis 272. The edge 220a-2 is farther from the electron source 205 than the central axis 272. Due to the heel effect in the generation of the x-ray beam 270, the intensity in the portion 274 may be higher and more uniform than the intensity in the portion 276. In the portion 276, the intensity may drop faster at the edge 220a-2 closer to the collimator 220a.

[0053] The anode heel effect or heel effect refers to the lower field strength or x-ray flux in a portion of the x-ray beam 720 closer to the anode than to the cathode or electron source 205 due to less x-ray emission from the target material at angles perpendicular to the electron beam or greater. The 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. Since the x-rays are generated deeper in the target 206 material, those x-rays also pass back out of the target 206 material before the x-rays can proceed to the detector 230. More target 206 material needs to be traversed 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). The increase in target 206 material results in more reabsorption of x-rays by the target 206 material, resulting in fewer x-rays arriving at the field at angles perpendicular to the electron beam 210. In contrast, x-rays emitted at angles closer to the incident electron beam 210 pass through less target 206 material and are less reabsorbed. The net result is that the field intensity and x-ray flux toward the cathode or electron source 205 are greater than the field intensity and x-ray flux toward the target 206. This uneven beam effect, or heel effect, can negatively impact detection results in x-ray imaging.

[0054] In some embodiments, an x-ray filter 260 may be disposed in the x-ray beam 270. The x-ray filter 260 is shown downstream of the collimator 220a; however, in other embodiments, the x-ray filter 260 may be disposed in other locations. The x-ray filter 260 may include materials of various thicknesses, such as molybdenum (Mo), rhodium (Rh), silver (Ag) and aluminum (Al), copper (Cu), stainless steel, combinations of such materials, and the like. The x-ray filter 260 may be configured to adjust the intensity of the x-ray beam 270 so that portions 274 and 276 are more uniform, thereby mitigating the heel effect.

[0055] In some embodiments, an x-ray source 200a is used with a detector 230 to generate an image based on a portion 240 of a patient 250. For example, portion 240 may be a 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 remaining portion may be imaged with an x-ray beam where intensity variations due to a heel effect have a reduced effect (e.g., the heel effect is applied to a narrower portion of the breast with a lower mass density). For example, for a 15 degree angle of surface 205a, the variation due to the heel effect may range from 80% to 100%. Thus, for a given image quality during operation of x-ray source 200a, a reduced dose may be accepted by the patient. In addition, using a substantially full-field x-ray beam 270 may allow a reduced source-to-image distance (SID), thereby increasing the imaging x-ray dose, allowing a reduction in power for the same imaging x-ray dose, etc.

[0056] In some embodiments, a smaller angle may be used on the surface 206a of the target 206. For example, a nanotube (NT) emitter of size w1 (width) x l1 (length) produces an electric focal spot size (FSS) of w2 (width) x l2 (length) on the surface 206a after the electron beam is focused. The electron FSS on the surface 206a depends on the focusing electrode design, where the smaller the NT emitter size (w1 x l1), the smaller the electron FSS (w2 x l2) on the surface. The x-ray FSS of w3 (width) x l3 (length) is determined by the angle (θ) between the electron FSS and the surface 206a. W3 is equal to w2, and l3 is equal to l2 x sin (θ). At a given x-ray FSS, a smaller anode angle allows for a larger electron FSS and a larger emitter. A larger NT emitter can produce a larger emission current. A larger electron FSS on the surface 206a distributes the heat load over a larger area, which allows for higher tube power and x-ray dose output.

[0057] Therefore, as the impact of the heel effect is reduced, a smaller angle can be used on the surface 206a. The smaller angle allows the current or size of the emitter in the electron source 205 to be increased. For example, a larger size field emitter can provide a larger current; however, the larger size will result in a larger x-ray FSS. However, the angle of the surface 206a can be reduced to maintain the x-ray FSS while still increasing the dose at the same or similar SID.

[0058] Fig.102 is a block diagram of an imaging system according to some other embodiments. Imaging system 200b may be similar to imaging system 200a as described above. However, imaging system 200b includes a collimator 220b having a different configuration. Collimator 220b includes an edge 220b-2 substantially aligned with central axis 272. In other embodiments, edge 220b-2 may be in a different position, such as closer to electron source 205. Due to the position of edges 220b-1 and 220b-2 of collimator 220b, the portion of x-ray beam 270 that leaves the collimator is substantially only portion 274 or a subset of portion 274. The heel effect on portion 274 may be reduced, resulting in an improved uniformity of x-rays passing through collimator 220b. In some embodiments, x-ray filter 260 may be omitted because the uniformity of x-rays in portion 274 may be sufficient. For example, for a 15 degree angle of target surface 206a, the x-ray intensity may vary from about 90% to 100%. Additionally, imaging system 200b may have greater strength at the distal end of portion 240 .

[0059] In some embodiments, the imaging system 200b allows the patient 250 to be viewed in conjunction with the system 200b. Fig. 9 On the side opposite to that side. In some embodiments, the use of a distributed electron source 205 such as those described above can achieve additional space for the patient 250 relative to an electron source 205 using a rotating anode. The number of external accessories on the patient 250 side of the system 220b can be reduced, thereby leaving more room for the patient 250. For example, high voltage connections, ion pumps, aspirators, tubing, etc. can leave more room for the patient 250. In addition, the use of a distributed electron source 205 achieves the flexibility of not using a rotating anode. Therefore, the bearings, rotors, stators, etc. from the rotating anode may not be present on one side of the patient 250. The patient 250 can be positioned closer to the x-ray beam 270, thereby minimizing the amount of the chest wall of the patient 250 missing from the image.

[0060] refer to Fig. 9 and Fig.10 In some embodiments, the collimator 220 may be adjustable. For example, the position of the edge 220a-2 / 220b-2 may be adjustable so that the edge Fig. 9 Move to the position in Fig.10 In other embodiments, other aspects of the collimator may be moved. For example, the position, aperture, shape, etc. may be adjusted to achieve a desired opening relative to the central axis 272 and portions 274 and 276.

[0061] Fig.11is a flow chart of a technique for operating a system having 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 can be used with various systems described above. For example, reference Figure 1 and Fig.11 , emitting the first x-ray beam may be performed by x-ray source 101a-0, and emitting 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 corresponding emitters 102 and 104.

[0062] refer to Figure 2 and Fig.11 , the emission of one of the x-ray beams may be the result of the plurality of electron beams 110 - 1 and 110 - 2 being focused on the target 106. Figure 3A , Figure 3B and Fig.11 In some embodiments, the focusing may be modified so that the electron beams 110 - 1 and 110 - 2 are focused on different areas or the same area of ​​the target 106 to generate multiple or single x-ray beams, respectively.

[0063] Fig.12 1 is a block diagram of a system with multiple x-ray sources according to some embodiments. In some embodiments, the x-ray source 101 may be coupled to the 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 device, a discrete circuit, a combination of such devices, and the like. The control logic 1200 may include external interfaces, such as address and data bus interfaces, interrupt interfaces, and the like. The control logic 1200 may include other interface devices that connect the control logic 1200 to internal components and external components, such as a logic chipset, a hub, a memory controller, a communication interface, and the like. 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 to apply voltage and / or supply current to the emitters 102 and 104, the focusing electrode 112, the target 106, and the like.

[0064] In some embodiments, emission of an x-ray beam may be the result of emitters of different sizes emitting an electron beam 110 toward the target 106 .

[0065] Some embodiments include a system comprising: a plurality of x-ray sources (101), each x-ray source (101) comprising: 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 a first x-ray source (101) in the x-ray sources (101) is different from a second x-ray source (101) in the x-ray sources (101).

[0066] In some embodiments, the target (106) of the x-ray source (101) is part of a linear target (106).

[0067] In some embodiments, the linear target (106) has an aspect ratio greater than or equal to at least one of 2:1, 10:1, and 20:1.

[0068] In some embodiments, the linear target (106) is a flat, curved, or segmented linear target (106).

[0069] In some embodiments, the x-ray source (101) is configured such that the corresponding x-ray beams converge substantially onto a single point.

[0070] In some embodiments, the first plurality of x-ray sources (101) includes at least one field emitter; and another x-ray source (101) in the x-ray sources (101) includes a filament, a low work function emitter, a reserve cathode, or a photoemitter.

[0071] 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).

[0072] In some embodiments, the first x-ray source (101) in the x-ray source (101) includes a first electron source (102, 104), the first electron source including at least one emitter; the second x-ray source (101) in the x-ray source (101) includes a second electron source (102, 104), the second electron source including at least one emitter; and wherein: the first electron source (102, 104) and the second electron source (102, 104) are configured so 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 point 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 point on the corresponding target (106).

[0073] In some embodiments, the first maximum current is greater than the second maximum current.

[0074] In some embodiments, the first maximum current is at least one of 2 times, 10 times, and 100 times the second maximum current.

[0075] In some embodiments, at least some of the x-ray sources (101) are substantially identical.

[0076] In some embodiments, at least three of the x-ray sources (101) are substantially identical.

[0077] In some embodiments, the first x-ray source (101) includes a first emitter and a second emitter; and the first emitter is configured to generate a maximum current that is higher than a maximum current of the second emitter.

[0078] 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 the emitters onto a single focal point.

[0079] In some embodiments, the first x-ray source (101) includes: a plurality of emitters; and a plurality of focusing electrodes (112), wherein the plurality of focusing electrodes are configured to controllably focus the electron beams (108, 110) from the emitters on a single focal point and to controllably focus the electron beams (108, 110) from the emitters on a plurality of focal points.

[0080] In some embodiments, the system further comprises a first vacuum enclosure (120, 282), the first vacuum enclosure comprising the first x-ray source (101); and a second vacuum enclosure (120, 282) separated from the first vacuum enclosure (120, 282), the second vacuum enclosure comprising a second x-ray source (101).

[0081] In some embodiments, for at least one of the x-ray sources (101): a surface of the target (106) is disposed at an angle other than perpendicular relative to an 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 a central axis (272) of the x-ray beam prior to entering the collimator (220).

[0082] In some embodiments, a second edge of the collimator (220) opposite to the first edge is located at the central axis (272) of the x-ray beam before entering the collimator (220) or closer to the electron source (102, 104) than the central axis (272) of the x-ray beam before entering the collimator (220).

[0083] In some embodiments, the position of the collimator (220) relative to the x-ray beam is adjustable.

[0084] 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).

[0085] In some embodiments, the target (106) of the first x-ray source (101) has a different slope than the target (106) of the second x-ray source (101).

[0086] In some embodiments, the target (106) of the first x-ray source (101) has a material that is different from a material of the target (106) of the second x-ray source (101).

[0087] 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).

[0088] Some embodiments include a method comprising: emitting a first x-ray beam from a first x-ray source (101) that includes at least a portion of a target (106); and emitting a second x-ray beam from a second x-ray source (101) that includes at least a portion of the target (106); wherein the first x-ray source (101) is different from the second x-ray source (101).

[0089] In some embodiments, the target is a linear target.

[0090] 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 the collimator (220).

[0091] In some embodiments, emitting the first x-ray beam includes emitting a first electron beam (108, 110) from a first electron source (102, 104) including a plurality of emitters toward a target (106); and emitting the second x-ray beam includes emitting a second electron beam (108, 110) from a second electron source (102, 104) including at least one emitter toward the target (106); wherein a first maximum current of the first electron beam (108, 110) at a first focal point on the target (106) is different from a second maximum current of the second electron beam (108, 110) at a second focal point on the target (106).

[0092] In some embodiments, the at least one emitter of the second electron source (102, 104) includes a first emitter and a second emitter; and the method further includes: emitting the second electron beam (108, 110) from the first emitter of the second electron source (102, 104) at a first current during a first operation; and emitting the second electron beam (108, 110) from the second emitter of the second electron source (102, 104) at a second current greater than the first current density during a second operation.

[0093] In some embodiments, the first operation is a three-dimensional imaging operation; and the second operation is a two-dimensional imaging operation.

[0094] In some embodiments, the at least one emitter of the second electron source (102, 104) comprises a plurality of emitters; and the method further comprises focusing the electron beam (108, 110) from the emitter of the second electron source (102, 104) at the second focal point.

[0095] In some embodiments, the first maximum current is less than the second maximum current.

[0096] In some embodiments, an x-ray beam generated in response to the second electron beam (108, 110) is collimated with a collimator (220) such that 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 closer to the second electron source (102, 104) passes through the collimator (220).

[0097] Some embodiments include a system comprising: a plurality of devices for emitting electron beams; and a device for generating x-rays in response to the electron beams; wherein a first combination of a first device for emitting electron beams and a device for generating x-rays in response to the electron beams is different from a second combination of a second device for emitting electron beams and a device for generating x-rays in response to the electron beams. Examples of devices for emitting electron beams include electron sources 102 and 104, etc. Examples of devices for generating x-rays in response to the electron beams include target 106, etc.

[0098] In some embodiments, a first maximum current on a device for generating x-rays of a first electron beam from one of the devices for emitting electron beams is different than a second maximum current of a second electron beam from another of the devices for emitting electron beams.

[0099] In some embodiments, the system further comprises means for collimating the x-ray beam. Examples of means for collimating the x-ray beam include collimator 220.

[0100] Some embodiments include a system comprising: an electron source (102, 104) comprising a plurality of emitters; and a target (106); wherein: the emitters of the electron source (102, 104) are configured to emit electrons toward a plurality of focal points 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.

[0101] Some embodiments include a system comprising: a first electron source (102, 104), the first electron source comprising at least one emitter; a second electron source (102, 104), the second electron source comprising 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 so 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 point 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 point on the target (106).

[0102] Although structures, devices, methods and systems have been described according to specific embodiments, it should be readily appreciated by those skilled in the art that many variations of the specific embodiments are possible, and therefore any variation thereof should be considered to be within the spirit and scope disclosed herein. Therefore, many modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

[0103] The claims accompanying this written disclosure are hereby expressly incorporated into this written disclosure, wherein each claim may stand on its own as a separate embodiment. This disclosure includes all permutations of an independent claim and its dependent claims. In addition, additional embodiments that can be derived from subsequent independent and dependent claims are also expressly incorporated into this written description. These additional embodiments are identified by replacing the dependencies of a given dependent claim with the phrase "as any of the claims beginning with claim [x] and ending with the claim immediately preceding the given dependent claim", wherein the bracketed term "[x]" is replaced with the number of the most recently recited independent claim. For example, for the first claim group beginning with independent claim 1, claim 4 may be dependent on any of claims 1 and 3, wherein these separate dependencies result in two different embodiments; claim 5 may be dependent on any of claims 1, 3, or 4, wherein these separate dependencies result in three different embodiments; claim 6 may be dependent on any of claims 1, 3, 4, or 5, wherein these separate dependencies result in four different embodiments; and so on.

[0104] Recitation of a claim with respect to the term "first" for a feature or element does not necessarily imply the presence of second or additional such features or elements. Embodiments of the invention claiming exclusive properties or characteristics are defined as follows.

Claims

1. A system comprising: A plurality of x-ray sources, each x-ray source comprising: 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; in: 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 comprises 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 parts of a linear target, and each target is disposed at a different position along the linear target; and The electron source of the first x-ray source and the electron source of the second x-ray source are configured so that a first maximum current of the electron beam from the electron source of the first x-ray source at a first focal point on a corresponding target is different from a second maximum current of the electron beam from the electron source of the second x-ray source at a second focal point on the corresponding target.

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

1.

3. The system of claim 1, wherein: The electron source of the second one of the x-ray sources includes a filament, a low work function emitter, a reserve cathode, or a photoemitter.

4. The system of claim 1, wherein: The first maximum current is at least one of 2 times, 10 times, or 100 times the second maximum current.

5. The system of claim 1, wherein: At least some of the x-ray sources are substantially identical, or At least three of the x-ray sources are substantially identical.

6. The system of claim 1, wherein: the first x-ray source comprising a first emitter and a second emitter, the first emitter and the second emitter configured to generate the electron beam at the first focal point from the electron source of the first x-ray source; and The first transmitter is configured to generate a maximum current that is higher than a maximum current of the second transmitter.

7. The system of claim 1, wherein the first x-ray source comprises: Multiple transmitters; as well as A plurality of focusing electrodes are configured to controllably focus the electron beam from the emitter on a single focal point and to controllably focus the electron beam from the emitter on a plurality of focal points.

8. The system of claim 1, further comprising: a first vacuum enclosure, the first vacuum enclosure comprising the first x-ray source; A second vacuum enclosure is separate from the first vacuum enclosure, the second vacuum enclosure including the second x-ray source.

9. The system of claim 1, wherein for at least one of the x-ray sources: The surface of the target is disposed at an angle other than perpendicular to the associated electron beam; and 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 entering the collimator.

10. The system of claim 9, wherein: A second edge of the collimator opposite to the first edge is located 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.

11. The system of claim 1, wherein: The target of the first x-ray source has a different slope than the target of the second x-ray source; and / or The target of the first x-ray source has a material that is different from the material of the target of the second x-ray source.

12. The system of claim 1, further comprising: A cooling system is configured to cool the target of the first x-ray source differently than the target of the second x-ray source.

13. A method comprising: Emitting a first x-ray beam from a first x-ray source including a field emitter includes: emitting the first electron beam from a first electron source toward a first portion of a target; and Emitting a second x-ray beam from a second x-ray source including an emitter different from the field emitter includes: emitting a second electron beam from a second electron source toward a second portion of the target different from the first portion of the target; in: the first x-ray source is different from the second x-ray source; and The target is a linear target; and The first electron source of the first x-ray source and the second electron source of the second x-ray source are configured so that a first maximum current of the first electron beam from the first electron source of the first x-ray source at a first focal point on a first portion of a target is different from a second maximum current of the second electron beam from the second electron source of the second x-ray source at a second focal point on a second portion of the target.

14. The method according to claim 13, wherein: The first electron source comprises a plurality of emitters; and The second electron source includes at least one emitter.

15. The method of claim 13, wherein: The emitter of the second electron source includes a first emitter and a second emitter; and The method further comprises: emitting the second electron beam at a first current from the first emitter of the second electron source during a first operation; as well as The second electron beam is emitted from the second emitter of the second electron source during a second operation at a second current greater than the first current.

16. The method of claim 13, wherein: The emitter of the second electron source comprises a plurality of emitters; and The method also includes focusing the electron beam from the emitter of the second electron source at the second focal point.

17. A system comprising: a plurality of devices for emitting electron beams; as well as means for generating x-rays in response to said electron beam; in: a first combination of a first means for emitting an electron beam and said means for generating x-rays in response to said electron beam of said first means for emitting an electron beam comprising a field emitter and being different from a second combination of a second means for emitting an electron beam and said means for generating x-rays in response to said electron beam of said second means for emitting an electron beam; The second means for emitting an electron beam comprises an emitter other than a field emitter; the means for generating x-rays in response to the electron beam of the first means for emitting an electron beam being disposed 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; and A first maximum current on a 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 of a second electron beam from another of the means for emitting an electron beam.

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