CN101726501A - Method and system for x-ray imaging - Google Patents
Method and system for x-ray imaging Download PDFInfo
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- CN101726501A CN101726501A CN200910174032A CN200910174032A CN101726501A CN 101726501 A CN101726501 A CN 101726501A CN 200910174032 A CN200910174032 A CN 200910174032A CN 200910174032 A CN200910174032 A CN 200910174032A CN 101726501 A CN101726501 A CN 101726501A
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Abstract
A technique is provided for imaging a view field (72) using an X-ray source (12) comprising two or more emission points (70). The two or more emission points (70) may be independently operated. Independent operation of the two or more emission points (70) in performed in accordance with a list of commands that specifies the operation of the emission points (70). The list of commands, in one embodiment, is stored in a sequence buffer (32). In other embodiments, the list of commands is generated for a given usage, without being stored in a sequence buffer (32).
Description
Technical field
The disclosure is usually directed to the non-invasive imaging field, and relates more particularly to computed tomography (CT) imaging field.Especially, the disclosure relates to scanner structure useful in the CT imaging and command sequence.
Background technology
The CT scan device is operated from the fan-shaped of X-ray source or taper X-beam by projection.X-ray source is being launched the X-ray by the object of imaging (for example patient) position, a plurality of visual angle on every side, when they pass through, by the object attenuate X-rays bundle of imaging.The light beam that is attenuated is by one group of detector elements, and this detector element produces the signal of the intensity of the X-beam of representing incident.This signal is processed to produce the data of expression along the line integral of the attenuation coefficient of the described object of X-raypath.These signals are commonly referred to as " data for projection " or are " projection ".By using reconfiguration technique (for example filtering back projection), can put out useful image in order according to projection.This image can be by successively in conjunction with to form the volume drawing of area-of-interest.In medical environment, then can be from the volume of the image of reconstruct or drafting location or discern interested pathology or other structural remodeling.In other environment, can find out interior article of luggage or parcel or the defective in structure or the manufactured goods.
Usually expectation is that development has high room and time resolution, preferable image quality and along the CT scan device of the good coverage of z-axle (being the longitudinal axis of CT scan device).In order to satisfy some or all these target, what may expect is that the coverage (coverage) that is provided by detecting device is provided, thereby allows the bigger scanning coverage on one or more dimensions.For example, the longitudinal axis coverage of detecting device can increase by the line number that increases the detector element in the detecting device.
This method has caused developing the CT system with bigger detecting device.Yet because a variety of causes, bigger detecting device may not expected.For example, but as a kind of expectability, bigger detecting device is that more expensive also more being difficult to produced with relevant collection electronic equipment.In addition, the mechanical subsystem of the detecting device that responsible support and/or rotation are bigger also may need bigger and more complicated and/or may suffer bigger mechanical stress.In addition, the cone angle of large-scale detecting device and increase (promptly by external detector capable to the source focus right angle) related.The pseudo-shadow of cone beam that increases in the cone angle of the increase that is faced toward by the detecting device longitudinal boundary and the image of reconstruct is related successively.When cone angle increased above a certain limit, for axial scan or stepping and shooting scanning (shoot scanning), it is serious that deterioration of image can become.For this reason, it may be difficult increasing the scanning coverage by the longitudinal size that increases detecting device simply.Therefore may expect to be used to use detecting device standard or littler to obtain the technology of high room and time resolution, preferable image quality and good coverage.
Summary of the invention
Present technique provides novel method and apparatus, and it is used to provide two or more discrete X-ray emission points, i.e. focal spot (focal spot), its by lateral excursion (promptly having different xy-coordinates) with or vertical misalignment (promptly having different z-coordinates).For example, the source can be offset on orientation (azimuthal) direction so that after rotation, each source provides the particular subset of the required projection line of the interior imaging object of reconstruction visual field.The source can alternately be activated, but needn't be with the interval that equates, promptly some sources can be activated more continually or activate the longer duration than other source.One or more detecting devices can use together with two or more sources.In one embodiment, detecting device can have in the relatively little plane size and can be flat-panel detector during some are implemented.
In certain embodiments, can stipulate the operation of each focal spot according to activating timing, energy, duration, focal spot size or the like by a row order or instruction.Similarly, can stipulate the activation of one or more detecting devices and the others of operation or CT system by a row order or instruction.The such row order of control that is used for the others of focal spot operation, detecting device operation or CT system can be called as command sequence.This command sequence can be stored in the sequence buffer of CT system or can be sent to the CT system simultaneously with the operation of CT system.Can exist and each single X-ray pulse and/or the single command that is associated with each single detecting device frame (frame).
According to an embodiment, provide CT imaging system.This CT imaging system comprises a plurality of discrete X-ray emission focal spots and is configured to one or more detecting devices of the X-ray that detection sent by these a plurality of X-ray emission focal spots.This CT imaging system also comprises X-ray controller that is configured to a plurality of discrete X-ray emission focal spots of independent operation and the data acquisition system (DAS) that is configured to read output signal from one or more detecting devices.This CT imaging system also comprises the sequence buffer of a row order of the operation that is configured to storage control X-ray controller.
According to further embodiment, provide the sequence buffer.This sequence buffer comprises data store organisation.Command sequence physically is coded in the data store organisation.This command sequence comprises the instruction of a plurality of X-ray emission focal spots that are used for operating independently distributed X-ray source.
According to additional embodiments, provide a kind of method.This method comprises the behavior of a row order of handling the operation that relates to imaging system.Operate a plurality of X-ray focal spots of distributed X-ray source individually according to this row order.
According to another embodiment, provide a kind of method.This method comprises the behavior that distributed X-ray source is provided, and this distributed X-ray source comprises a plurality of discrete and X-ray emission focal spots that can operate respectively.One or more detecting devices also are provided, and it is configured to produce signal in response to the X-ray by distributed X-ray source emission.Sequence buffer also is provided, and it can store a row order that is used to operate a plurality of X-ray emission focal spots.X-ray controller is electrically connected to distributed X-ray source and sequence buffer.X-ray controller can be operated a plurality of X-ray emission focal spots independently according to this row order.Data acquisition system (DAS) is electrically connected to one or more detecting devices.Data acquisition system (DAS) can be read the signal that is produced by one or more detecting devices.
Description of drawings
Aforesaid and other advantage and feature of the present invention will be by reading following detailed description and by becoming with reference to the accompanying drawings obviously, in the accompanying drawings:
Fig. 1 is according to sketch present embodiment, that be CT imaging system form, that be used to produce the exemplary imaging system of handling the back image;
Fig. 2 is the sequential chart according to the exemplary command sequence of present embodiment;
Fig. 3 is according to a kind of possible distributed X-ray source of present embodiment and the diagram of detector arrangement;
Fig. 4 is according to another possible distributed X-ray source of other present embodiment and detector arrangement diagram;
Fig. 5 is the plane internal view according to a pair of X-ray emission points in the configuration of visual field present embodiment, complete;
Fig. 6 is the plane internal view according to a pair of X-ray emission points present embodiment, in the half field-of-view configuration;
Fig. 7 is the plane internal view according to a pair of X-ray emission points in the configuration of visual field present embodiment, any;
Fig. 8 is the plane internal view according to four X-ray emission points in the configuration of visual field present embodiment, complete;
Fig. 9 is the plane internal view according to four X-ray emission points present embodiment, in the half field-of-view configuration;
Figure 10 is the plane internal view according to four X-ray emission points in the configuration of visual field present embodiment, any;
Figure 11 for according to present embodiment, have along the skeleton view of the CT scan device of the configuration of the launching site of longitudinal axis;
Figure 12 is according to a plurality of axial X-ray emission points of present embodiment and the side view of detecting device;
Figure 13 for according to present embodiment, have along the skeleton view of the CT scan device of the identical configuration of the launching site of the longitudinal axis;
Figure 14 has described the focal spot array according to the distributed X-ray source of present embodiment;
Figure 15 has described the r-θ figure of the prior art of half scanned scanning collection scheme; And
Figure 16 has described the r-θ figure of the half scanned scanning collection scheme of carrying out according to present embodiment.
Embodiment
Fig. 1 has illustrated with graphical method and has been used to obtain the also imaging system 10 of image data processing.In the embodiment shown, system 10 is computed tomography (CT) system, and it is designed to obtain the X-ray projection data, and this data for projection is reconstituted image, and shows and analyze being used for according to the present technique image data processing.Though this imaging system 10 is inquired into, can be applicable to other Noninvasive CT imaging background in this technology inquired into and configuration, for example the control of luggage or parcel examination and/or workmanship under the background of medical imaging.
In the embodiment shown in Fig. 1, CT imaging system 10 comprises the source 12 of x-ray radiation.So the place is inquired in detail, and the source 12 of x-ray radiation can be discrete by two or more, promptly launching site or focus (foci) that separate, that be used for the X-ray emission are formed.For example, traditional X-ray tube can be equal to single launching site.As selection, X-ray source (the solid-state X-ray source or the thermion X-ray source that for example have field emitter) can comprise a plurality of launching site.This is solid-state or the thermion X-ray source can be configured so that each launching site forms array fixing or that rotate or fixing ring.
Though this instructions can be inquired into the rotation of X-ray source 12, as contingent in traditional third generation CT system, this discussion of rotation X-ray source 12 also comprises function equivalent.For example, for the solid-state X-ray source 12 that is configured to encircle, source 12 and corresponding launching site can physically not rotate.But, can activate along the launching site of ring to be equal to the continuous or discrete mode that surrounds into as body rotation X-ray source 12 effectively.Therefore, when X-ray source 12 or launching site are described in the rotation, it will be understood that this rotation can be produced by the physics rotation of the element in source 12 or source 12 or by this functional equivalent deposits yields.
As mentioned above, in certain embodiments, X-ray source 12 can be distributed X-ray source, and it allows to produce the X-ray on the wide region of focal spot (being launching site) position.For example, in distributed X-ray source embodiment, each launching site can be at interval tens of centimetres, as 10cm, and 15cm, 20cm, 25cm, 30cm etc.This distributed X-ray source can be used for producing the X-ray of the different piece of passing the patient or the object to be imaged basically and/or is used to produce the X-ray that passes the patient or the object to be imaged with different basically position angles.
The example of this distributed X-ray source comprises the electron beam ct scanner, and it produces the X-ray by making the inswept one or more target rings around the scanner visual field of electron beam.This layout can produce the X-ray from different position angles with scanning sequence fast.Other scanning beam X-ray source also can be understood as that distributed X-ray source.In addition, in certain embodiments, distributed X-ray source can be fixing in essence, adopts the on-mechanical motion to produce the X-ray around the patient or the object to be imaged with different viewpoint (view).In this fixing embodiment, distributed source can be based on one or more scanning beams or based on a plurality of discrete electron emitters or the combination of these two kinds of technology.In addition, in certain embodiments, the distributed source architecture can be rotated.For example, in such embodiment, distributed X-ray source can be based on the 2D-array of discrete electron emitter.
In certain embodiments, X-ray source 12 can be positioned at from the nearest position of collimator 14.Collimator 14 can be made up of the collimation district (for example lead or tungsten optical gate) of each launching site that is used for source 12.Collimator 14 General Definitions enter the size and dimension of one or more radiation beam 16 in the zone that main body (for example human patients 18) is arranged in.Radiation beam 16 can be taper usually, and it depends on the structure of detector array of following discussion and desired collecting method.Radiation be attenuated the main body that part 20 is passed provides decay, and impact the detector array of representing with Reference numeral 22 usually.
Detecting device 22 is formed by a plurality of detector element usually, and its detection is passed and near the X-ray of interested main body.Detecting device 22 can comprise the multi-row detector element.When adopting this multi-row detector, radiation beam 16 will have the non-zero cone angle related with it, because the launching site of detector line and activation is not in a plane.The abstract concept that following example can be formulated this z-scope (extent) is with simplified illustration, promptly by restriction to the discussion of the detector element of launching site in a plane that activates.Yet following geometric discussion and example are equally applicable to multi-row detector.
Each detector element is when being impacted by the X-ray, and it understands the electric signal of the intensity of the X-beam that produces the position that is illustrated in element during light beam collision detecting device.Generally speaking, each position, visual angle around interested main body obtains signal so that can collect a plurality of X-ray radiography views.As described below, obtain and handle the image of these signals with feature in the reconstruct main body.
In the embodiment shown in fig. 1, system controller 24 can be by the motion of motor controller 34 control gyrator systems 26 and linear orientation subsystem 28.In imaging system 10 (wherein source 12 and/or detecting device 22 can be rotated), gyrator system 26 can be around patient 18 rotation X-ray sources 12, collimator 14 and/or detecting device 22 through one or multi-turn.Should be pointed out that gyrator system 26 can comprise frame.Linear orientation subsystem 28 can make patient 18 or more specifically the patient table carry out linear displacement.Therefore, the patient table can be moved the image with the specific region that produces patient 18 linearly in frame.
The source 12 of radiation can be disposed in X-ray controller 30 controls in the system controller 24.X-ray controller 30 can be configured to provide electric power and timing signal to X-ray source 12.In addition, if X-ray source 12 is distributed source (for example being configured to the solid-state of array or ring or thermion X-ray source), it is that launching site activates that X-ray controller can be configured to provide focal spot position.For example, X-ray controller 30 can be implemented as high voltage switch circuit to connect and to cut off each focal spot (being launching site) in distributed X-ray source.This circuit can comprise logic controller or communicate by letter to control different high pressure stage (stage) with logic controller.
In one embodiment, so the place is inquired into, and X-ray controller 30 can comprise the sequence buffer 32 of storage different command or instruction (for example command sequence) or communicate by letter with sequence buffer 32, with the different focal spot of operation X-ray source 12.Especially, different X-ray focal spot command sequences can be used for changing picture quality, noise, scattering, X-ray source heat, patient dose or other parameter relevant with the operation of imaging system 10.For example, command sequence can be a row order, and wherein each order comprises the index of focal spot to be activated and is used for mA, kVp, focal spot size and/or the residence time (duration of pulse) that each focal spot activates.Sequence buffer 32 also can be stored " dead time " between focal spot activates hard coded or programmable and crosstalk to help to reduce.In addition, being stored in command sequence in the sequence buffer 32 can comprise the detecting device pattern (for example photon counting is to the energy intergration model, high flux (flux) is to small throughput pattern or the like), this detecting device pattern can be utilized by X-ray controller 30 and/or data acquisition system (DAS) 36 during operation.In practice, sequence buffer 32 can be implemented as memory device or be suitable for other storage organizations that the storage computation machine executes instruction.For example, sequence buffer 32 can be embodied in solid storage device (for example be used as based on ROM in the system of processor or RAM or be used as the storage chip of solid state hard disc), light storage device (for example CD), magnetic storage apparatus (for example traditional hard disk) or any other suitable data storage organization, and this data store organisation is suitable for storing and is used to the command script of operating each focal spot of distributed X-ray source and/or being used to operate one or more detecting devices 22 of imaging system 10.
The size of sequence buffer 32 can be based on quantity that is stored in the instruction in the sequence buffer 32 and length.In one embodiment, each row instruction can comprise and is used for (sampling period for example in sampling period number, 1,5,15 or the like) 2 byte field, be used for operational code, promptly and the instruction (for example code " 7 " can represent to trigger the instruction of focal spot 7) 1 byte field, three 1 byte field, it is used to determine, the modifier (modifier) or the variable of certain others of modification or complement operation sign indicating number or dos command line DOS (for example, code " 27 ", " 30 " and " 45 " can represent that the source spot that is activated will trigger the back with 27mA be activated 30 μ s, 45 μ s receiving).It can be increased 6 bytes in typical sub-view.Therefore, in such embodiment, suppose that sampling rate is 7kHz, sequence buffer is of a size of every scanning second 42kB+akB.In other was implemented, the sequence buffer size can be about 50kB to about 60kB per second.
In certain embodiments, sequence buffer 32 can not be present in the system controller or can not be used.For example, in certain embodiments, processor and can be used for producing the aforesaid command sequence that is used for using immediately with the suitable storer (it can be or can not be sequence buffer 32 or storer 40) of processor communication, that is, can not rely on sequence that prestore or generation in advance and interim or " hastily " generation command sequence.Such processor can interrelate with system controller 24, computing machine 38 or other suitable system based on processor (it is communicated by letter with CT system 10 or forms CT system 10) with suitable storer.Therefore, in such embodiments, sequence buffer 32 or other storage organization (for example storer 40) can exist but can be use as memory buffer unit, and as being used to produce staging area (staging area) use of the command sequence that i.e. uses produced of existing side by side.
Do not have sequence buffer 32 or do not providing among the embodiment of sequence buffer 32 as the part of system controller 24, order can change the raw capacity that the data service load that is sent in real time on system controller 24 and the link can be lower than sequence buffer into.(it has among the embodiment of 50 focal spots and 20 possible grid levels (grid level) (being the mA level) having distributed X-ray source, suppose that the sampling period number needn't be transmitted, then every typical case's sampling periods 3 byte will be enough, if two focal spots are activated then 6 bytes simultaneously.Suppose that sampling rate is 7kHz, then the baud rate more than or equal to the 500k baud will be enough.
In certain embodiments, can only use 5 bits (being 0-4) the delay with μ s (microsecond) of focal spot between activating of encoding.In such embodiment, can the different moment in the same sampling period but after triggering activate two focal spots.For example, first focal spot can be instructed to activate by 55 μ s after triggering, and second focal spot can be instructed to activate by 60 μ s after triggering.In such enforcement, 5 bits may be not enough to transmit these to postpone, yet the execution command of the logic in the sequence buffer can replace being fit to the delay transmission of order of time to obtain desired delay effectively, for example in this example up to residue less than 31 μ s.The expression of the such packing scheme of the fixedly stand-by period with 40 μ s is provided among Fig. 2.
The display 44 that is coupled to operator workstation 42 can be used for observing the image of reconstruct.In addition, scan image can be printed by the printer 46 that can be coupled to operator workstation 42.Display 44 and printer 46 also can directly or via operator workstation 42 be connected to computing machine 38.In addition, operator workstation 42 also can be coupled to picture archive and communication system (PACS) 48.Should be pointed out that PACS48 can be coupled to remote system 50, radiology information system (RIS), hospital information system (HIS) or be coupled to inside or external network, thereby make and to obtain visit this view data other people of diverse location.
One or more operator workstations 42 can be linked at and be used for output system parameter, desired inspection, visual image or the like in the system.Usually, the display that provides in system, printer, workstation and similar devices can be in data acquisition parts this locality, perhaps can for example link in the mechanism of image capturing system or other place or diverse place in the hospital away from these parts via one or more configurable networks (for example the Internet, Virtual Private Network etc.).
Can dispose above-mentioned CT imaging system 10 in various manners to improve room and time resolution, to improve picture quality, reduce patient's radiant quantity and/or improve vertical coverage.In fact, can realize 22 configurations of different source 12 and detecting device, it improves one or more in these parameters.For example, so the place is inquired into, and can adopt the X-ray source 12 that uses a plurality of launching site (being focal spot).Can be for example by adopting alternately activation mechanism or allowing to activate the activation of coordinates transmission point simultaneously so that only have one to activate at every turn.By this way, each launching site is when when activating, and can be provided at the subclass of the required projection line of reconstruction of objects in the given visual field.Yet the combination of these subclass allows the reconstruct of visual field.In addition, in the embodiment of a subclass once only obtaining the projection line that is associated with the visual field, big I is reduced in the plane of detecting device 22.In fact, big I is reduced to the degree of the flat-panel detector (being the radiographic detector panel) that may be utilized in the plane of detecting device 22.
Can carry out various X-ray source 12 configuration and activation schemes according to present technique.Many exemplary configuration and scheme here have been discussed.Yet should be understood that included example does not limit the scope of present technique.On the contrary, present technique can be interpreted as widely and be comprised a plurality of, the discrete launching site of any permission and any X-ray source configuration that is used for the activation scheme of this launching site.
For example, refer now to Fig. 3 and 4, described the example of different distributed X-ray sources 12 configurations.In example shown in Figure 3, contrary how much CT (inverse-geometry CT) structures in array source of standard have been described.In this example, X-ray source 12 is depicted as by 20 * 3 focal spots (being launching site 70) that are distributed in respectively on x (flatly (azimuthally)) and the z (longitudinally) to be formed.As being understood ground, can use similar geometric configuration, it adopts the launching site 70 of varying number, for example z make progress 1,2,3,4,5 ..., 100 or more multiple exit point and x make progress 2,3,4 ..., 1000 or more multiple exit point.Described structure comprises detecting device 22, for example flat-panel detector.In one embodiment, detecting device 22 is about 10cm * 10cm.Launching site 70 emission X-rays 16 are by visual field 72 shock detectors 22.
In the example that Fig. 4 describes, described the core form of contrary how much CT structures.In this example, distributed X-ray source 12 has about 30 * 3 launching site and two detecting devices 22 that are distributed in respectively on x (flatly (azimuthally)) and the z (longitudinally).In one embodiment, each detecting device 22 is about 10cm * 10cm.In other embodiments, can use detecting device 22 more than two.As being understood ground, can use similar geometric configuration, it adopts the launching site 70 of varying number, for example z make progress 1,2,3,4,5 ..., 100 or more multiple exit point and x make progress 2,3,4 ..., 1000 or more multiple exit point.
The purpose of the aforementioned discussion of the distributed X-ray source of property presented for purpose of illustration, below the example of Jian Huaing will be described the several embodiment about the present technique of the configuration of the launching site on directions X.For example, as depicted in figure 5, in the xy-plane, described a pair of discrete launching site 70 skew in the horizontal direction as radiation source 12.Launching site 70 can be configured to the identical vertical range of distance detector 22 (for example flat-panel detector 60) or can be different distances.Each launching site 70 can be the X-ray tube, based on other the focus that when being activated, can launch the X-ray from it of the focal spot of the distributed X-ray source of solid-state or thermionic emitter or some.X-ray source 12 and its corresponding launching site 70 can be by gridding (gridded).As described here, launching site 70 also can upwards be offset at z.
Launching site 70 can allow each launching site 70 from desired visual angle radiation beams 16 around visual field 72 rotations of expectation.When launching site 70 rotations, they can alternately be activated so that in the given moment launching site 70 emission X-rays only be arranged.Each launching site 70 can be configured to when being activated the emission fan-shaped radiation beam, and it surrounds the part (for example as visual field 72 depicted in figure 5 half) of visual field 72.Radiation beam 16 passes visual field 72 before at bump detecting device 22 (for example flat-panel detector 60), and any decay material in the visual field 72.For each activation of launching site 70, data acquisition system (DAS) 36 (Fig. 1) is read the signal that is produced by detecting device 22, and it can be processed to produce data for projection.Along with launching site 70 72 rotations around the visual field, the data for projection that is obtained combination or set is described whole visual field.
For example, as depicted in figure 5, first launching site 74 can be launched the X-ray in a part that comprises visual field 72 (for example half of visual field 72) fan-shaped when activating.Therefore, when first launching site 74 activated, detecting device 22 (for example flat-panel detector 60) can be this part and obtains data for projection.When first launching site 74 when being nonactivated, second launching site 76 can be activated, and is obtained data for projection to allow for by the part of the fan-shaped visual field that comprises 72 of the X-ray of second launching site, 76 emissions.Launching site 70 can center on visual field 72 rotations, is alternately activated with the visual angle of each expectation, comes reconstruction visual field 72 until obtaining desired data for projection.
As will being understood ground, by can obtain enough data for projection of reconstruction visual field 72 around the rotation less than whole process of the launching site 70 of visual field 72 by those of ordinary skills.In fact, half rotation add promptly 180 ° of angles () between two launching site 70+, can be provides data for projection with the enough rotations of reconstruction visual field 72.
In addition, a plurality of launching site 70 can be configured to make when activating their combination fan-shaped only to surround half or other parts of visual field 72, and promptly half field-of-view disposes.For example, with reference to figure 6, described two launching site 70, it is only comprising when activating in half part fan-shaped of visual field 72 launches the X-ray.As depicted, fan-shaped half of visual field 72 of only surrounding of the combination of first and second launching site 74,76.Limit in the plane that the fan angle alpha relevant with each launching site 70 make it possible to further to reduce detecting device 22 (being flat-panel detector 60 here) big or small because when launching site 70 was activation, less visual field 72 was by imaging.As one of ordinary skill will recognize, as depicted in figure 6, can obtain the enough data for projection that use half field-of-view to dispose reconstruction visual field 72 by whole process rotation around the launching site 70 of visual field 72.
In addition, will be appreciated that the same area that the X-ray of being launched by first launching site 74 and second launching site 76 does not pass visual field 72.Especially, pass the central area of visual field 72 by the X-ray of first launching site 74 emission, the object to be imaged or patient generally are positioned at its center in this central area.On the contrary, the outer peripheral areas that the X-ray of being launched by second launching site 76 passes visual field 72, it can comprise empty space or more uninterested by the zone of patient imaged or object.When 72 rotations around the visual field of first and second launching site 74,76 (that is, first launching site 74 continues the central area imaging of visual field 72 and the peripheral imaging that second launching site 76 continues visual field 72), this relation accurately keeps always.
Because this difference between first and second launching site 74,76, first and second launching site 74,76 do not need to be operated comparably, for example when the periphery of visual field 72 when being less or uninterested.For example, if necessary, can use second launching site 76 to obtain less view, that is, second launching site 76 can be activated not as first launching site 74 frequent.Such as, if necessary, can or less activate second launching site 76 every a viewpoint.Equally, can be with duration of reducing or work period or to operate second launching site 76 with respect to first launching site, 74 lower energy.
Same, if are more unessential words by the outer peripheral areas of second launching site, 76 imagings, then second launching site 76 can have the quality (promptly lower flux, lower spatial resolution etc.) lower than first launching site 74.Especially, if lower decay, lower resolution and/or higher noise can be accepted in the periphery of interesting areas 72, may be acceptable then than small throughput or than second launching site 76 of low spatial resolution.The differentiated activation of first and second launching site 74,76 and/or can allow using different dosage at the center of interesting areas 72 and peripheral patient 18 than the use of second launching site 76 of small throughput.By this way, the dosage that received of patient 18 can customize based on environment.
These notions can be expanded to any configuration between half field-of-view configuration and the configuration of full visual field or can have any configuration of interested unique central area 80 (being the core visual field).For example, as depicted in figure 7, the different piece of each limited visual field 72 of first and second launching site 74,76 promptly is respectively interested central area 80 and outer peripheral areas 82.As those skilled in the art will appreciate that ground, be similar to about the relevant discussion of Fig. 6 and describe relevant discussion in detail about the discussion of the interested central area 80 of Fig. 7 and outer peripheral areas 82 about Fig. 6.
Especially, with reference to figure 7, launch the X-ray in central area interested 80 that can be in comprising visual field 72 when first launching site 74 activates fan-shaped.By this way, first launching site 74 can produce the projection line relevant with interested central area 80.Can be when second launching site 76 activates at the area-of-interest 72 that comprises 80 outsides, central area interested radially or in periphery 82 fan-shaped launch the X-ray.For example, by fan-shaped one side of the X-ray of second launching site 76 emission can another side can be tangent with the edge of visual field 72 with central area interested 80 is tangent.By this way, second launching site 76 can produce projection line for the additional part that is not included in the visual field 72 in the central area 80 interested.
As the example of front, because whole visual field 72 is covered by single launching site 70 and detecting device 22, so the plane inside dimension of detecting device 22 can use single launching site 70 little such as fruit.For example, detecting device 22 can have in the relatively little plane size and in fact, can be flat basically, and for example flat-panel detector 60.For example, for the radius of the visual field 72 of the radius of the central area interested 80 of 15cm and 50cm, detecting device 22 can be the relevant detection device size that is associated with same field and single launching site 70 30% or still less.
Half scan-data collection can be used to obtain the data that are used for reconstruct central area 80 interested, i.e. the rotation of 180 °+α degree.Further, because fan angle alpha is than little when using single launching site 70, thus can carry out half scanning more quickly, thus the temporal resolution of raising provided for dynamic organ (for example heart) being carried out imaging.For example, when using second launching site 76, α can equal 15 ° rather than 50 °, thereby makes half scan-data collection can comprise 195 ° rotation rather than 230 ° of rotations of first launching site 74.Yet the whole process rotation (promptly 360 °) that may need first and second launching site 74,76 is to obtain the data that are used for the full visual field 72 of reconstruct (being complete reconstruct outer peripheral areas 82).
Aforesaid half field-of-view's configuration about Fig. 6 if necessary, can be obtained the less visual angle of using second launching site 76, when for example the peripheral view that provides when second launching site 76 is more unessential.Equally, discussed in the example as the front, second launching site 76 can be activated not as first launching site 74 frequent or can be activated reduce the duration.Similarly, as inquiring into before, if by the outer peripheral areas 82 more unessential words of second launching site, 76 imagings, then second launching site 76 can have the quality lower than first launching site 74, promptly lower flux or the like.
The differentiated activation of first and second launching site 74,76 and/or than the use of second launching site 76 of small throughput can allow within the interested central area 80 with outside patient 18 use different dosage.In fact, in some instances, for example treat the object of imaging or organ in interested central area 80, during image data acquiring, might allow the 76 non-activation of second launching site.In this is implemented, the data of obtaining corresponding to outer peripheral areas 82 will be incomplete, (if for example being arranged in this outer peripheral areas 82 by certain part of the object of imaging) but if necessary, these data still can be used the reconstruct in addition of special reconfiguration technique.By this way, the dosage that received of patient 18 can customize based on environment.
Although the example of front has been inquired into the realization that comprises two launching site 70, present technique can be expanded to three or more launching site 70.For example, can use three or more X-ray tubes or can use solid-state or thermion X-ray source 12 (it comprises three or more addressable launching site 70 that are configured to array or ring).Comprise that other X-ray source 12 discrete and addressable launching site 70 also can be suitable for using together with present technique.
For example, Fig. 8 has described four launching site 70 in the configuration of full visual field, and is similar with the description among Fig. 5.Launching site 70 can be configured to apart from the identical vertical range of flat-panel detector 60 or can be different distances.As inquiring into about Fig. 5, launching site 70 can rotate so that each launching site 70 can be from the visual angle radiation beams 16 of expectation around the visual field 72 of expectation.
When launching site 70 rotations, they can alternately be activated so that at given time a launching site 70 emission X-rays only be arranged.Each launching site 70 can be configured to emission fan-shaped radiation beam when being activated, and it surrounds the part of visual field 72.Radiation beam 16 passed any decay material in visual field 72 and the visual field 72 before bump flat-panel detector 60.For each activation of launching site 70, data acquisition system (DAS) 36 (Fig. 1) is read the signal that is produced by detecting device 22, and this signal can be processed to produce data for projection.Along with launching site 70 72 rotations around the visual field, the data for projection that is obtained combination or set is described whole visual field.As above discussion, in so full visual field configuration, available half scanning collection (promptly depending on geometric 180 °+certain additional angle) obtains enough projections of reconstruction visual field 72.
Similarly, can use more than two launching site 70 and implement half field-of-view configuration.For example, with reference to figure 9, described four launching site 70, its fan-shaped radiation beam 16 is surrounded half or some other parts of visual fields 72 usually.As mentioned above, each launching site 70 can alternately be activated, so that only has a launching site 70 to activate at every turn.Because it is big or small that the limited fan angle alpha relevant with each launching site 70, detecting device 22 can have in the plane of minimizing.In the configuration of this half field-of-view, the available whole process that centers on the launching site 70 of visual field 72 is rotated the enough data for projection that obtain reconstruction visual field 72.
In addition, as mentioned above, the different radiation areas of launching site restriction visual field 72.For example, first launching site 74 defines central areas and second launching site, 76 restriction outside radiation areas then.Similarly, the 3rd launching site 86 restrictions radiation areas and the 4th launching site 88 restrictions the radiation areas peripheral or outside then.Because the different radiation areas of launching site 70 restriction visual fields 72, so if the radiation areas that they limit are fully uninterested or little interest, then different launching site 70 can keep non-activation during imaging sequence.For example, if the outer peripheral areas of visual field 72 comprises empty space or not so for uninterested, then the 4th launching site 88 can keep non-activation.As half field-of-view's configuration of inquiring into before, use as the whole process of the launching site 70 that enough data for projection of half field-of-view depicted in figure 9 configuration reconstruction visual field 72 can be by centering on visual field 72 is rotated and obtained.
Similarly, as inquiring into about Fig. 6 and 7, the first, the second, the third and fourth launching site 74,76,86,88 does not need to be operated to reach following degree with being equal to: the different radiation areas of their restrictions have different property interested or different importance.For example, can activate each launching site 70 for the viewpoint (view) of varying number.For example, can activate first and second launching site 74,76, can activate the 3rd launching site 86 every a viewpoint, and can not activate the 4th launching site for any viewpoint for each viewpoint.This enforcement can allow the image that will be fabricated to have good quality towards the center of visual field, has relatively poor quality outside the center, and 72 outer peripheral areas does not produce image in the visual field.Similarly, different launching site (for example the 4th launching site 88) can be operated in the duration that reduces, perhaps to operate with respect to first launching site, 74 lower energy.Equally, based on the radiation areas of their restrictions, launching site 70 can be gone up different in quality (being flux).For example, in the X-ray tube was implemented, the 3rd and/or the 4th launching site 86,88 can be the X-ray tube of inferior quality (being small throughput).
Therefore, when the quantity of X-ray emission points 70 increased, the ability that makes x-ray dose be adapted to the patient 18 or the object to be imaged also can increase.Especially, possible radiation areas quantity can be along with the increase of the quantity of launching site 70 and is increased.When the quantity of radiation areas increases, adopt the chance of discrepant operation (for example activating and/or the duration) or different hardware configuration (for example small throughput X-ray tube) also can increase.By this way, the picture quality of the different piece of dosage that is received by patient 18 and image can customize based on environment.
Equally, the use of additional emission point 70 can be extended to any configuration or have the configuration of interested unique central area 80 (for example about core (cardiac) visual field 80 that Fig. 7 inquired into).For example, with reference to Figure 10, first and two launching site 74,76 can limit the central area interested 80 of visual field 72.On the contrary, third and fourth launching site 86,88 can limit the outer peripheral areas 82 of visual field 72.As inquiring into about Fig. 7 and 9, launching site 70 can be operated variantly or be constituted, so that can adapt to or adjust patient dose based on environment.For example, when outer peripheral areas 82 when being more uninterested or uninterested, the 3rd and/or the 4th launching site 86,88 can not be activated or can be only for the subclass at possible visual angle and be activated.Similarly, if outer peripheral areas 82 is more uninterested, then third and fourth launching site 86,88 can be activated with lower quality (for example using small throughput or big focal spot size).
As previous examples because single launching site 70 and detecting device 22 do not cover whole visual field 72, so detecting device 22 (for example flat-panel detector 60) if the comparable single launching site 70 that uses of plane inside dimension littler.Similarly, use half scan-data collection of first and second launching site 74,76 to can be used for obtaining the data that are used for the interested central area 80 of reconstruct, promptly 180 °+certain additional rotation angle.Yet, may need the whole process rotation (promptly 360 °) of the first, the second, third and fourth launching site 74,76,86,88 to obtain the data that are used for the full visual field 72 of reconstruct (being complete reconstruct outer peripheral areas 82).
Though the example of front has been described the explanation that is configured to simplify this notion of adopting two or four launching site 70, disclosed technology can extend to other configuration that wherein exists more than one launching site 70.Similarly, except described those visual field configuration be not excluded outside present technique and can from as the use of the multiple exit point 70 inquired into here benefit.
In addition, consider the distributed X-ray source configuration of Fig. 3 and 4, may be desirably in offset launch point 70 on the z direction sometimes.For example, as shown in figure 11, z skew can be applicable to continuous launching site 70, and the result produces the array of the launching site 70 that the main shaft with respect to CT scan device 100 tilts a little.This especially can be used for the helical cone beam collection, because the data set that generates can be by rearrangement with the collection of emulation with the acquisition of single-shot exit point.In order to obtain such result, the spacing (pitch) of the array that z is offset and therefore generates will depend on the pitch of using during the image acquisition.The Z skew can be conditioned the pitch (helical pitch) with adaptive expectation.
In addition, for pencil-beam and volume CT geometry, expectation be the additional emission point 70 that comprises along the longitudinal axis.Especially, the minimizing of the plane inside dimension of the detecting device that replacement is inquired into above or except the minimizing of the plane inside dimension of the detecting device inquired into above can allow the axial dimension of detecting device 22 to be reduced along the use of a plurality of launching site 70 of the longitudinal axis.For example, with reference to Figure 12, three launching site 70 disposing along the longitudinal axis of CT scan device 100 have been described.Can make launching site 70 alternately (for example sequentially) luminous so that only have a launching site 70 to activate at every turn.Having the mode that the detecting device 22 (for example flat-panel detector 60) of the axial dimension that reduces can be inquired into to be similar in the previous examples is used in combination with a plurality of vertical launching site.In the example as the front, the enforcement of present technique longitudinally consider than small-angle and therefore less detecting device 22 longitudinally use.
For example, with reference to Figure 13, described along three groups of identical (duplicate) launching site 94,96,98 of the longitudinal axis of CT scan device 100.In described example, every group of identical launching site 94,96,98 in the xy plane, share coordinate but on the z axle (promptly vertically) their position difference.
Example as before plane bias internal and vertical misalignment is described, and present technique disclosed herein can provide various benefits.For example, in the plane that reduces of detecting device 22 and/or longitudinal size can allow to use less, more cheap detecting device, flat-panel detector 60 (Fig. 5-10 and 12) for example.Usually, making less detecting device (especially flat-panel detector) can be easier and more cheap.
In addition, present technique can provide bigger spatial resolution, especially away from isocenter (isocenter).Particularly, single launching site can be relevant with corresponding big detecting device with big segment angle.Owing to the increase of so-called apparent (apparent) focal spot size causes the focal spot relevant with launching site to seem bigger at the edge of detecting device.The apparent focal spot size that increases can cause comparing with detector centre the lower spatial resolution in detector edge.Because the cause of the less apparent focal spot size of launching site 70, size (Fig. 5-10 and 12) can allow to improve the spatial resolution away from isocenter (promptly on the remainder of visual field) in the segment angle that reduces of the detecting device 22 that is used in combination with present technique and the less plane.
In addition, the use of a plurality of launching site 70 (Fig. 5-10) can allow the dynamic flux control during the image acquisition.For example, a plurality of launching site 70 can be activated consistance with the signal that keeps detecting device 22 places based on the visual angle variantly, and therefore raise the efficiency and the dynamic range at limitation detector place, perhaps for optimum dose or picture quality.Especially, under the imaging of medical background, patient 18 (Fig. 1) is oval-shaped usually in xsect, and this causes path difference by patient 18, and (that is, the X-ray path of passing patient 18 changes according to the position, visual angle with respect to patient 18.Conventional CT technology can be used butterfly filter disc (bowtie filter), is adapted to be by the full xsect of the body region of imaging, to compensate these different paths.
Yet present technique allows to regulate based on the real-time flux of patient 18 tissue (being virtual dynamic butterfly).Especially, with the visual angle corresponding to the path (for example by chest and back) of the weak point by patient 18, launching site 70 can be activated and have X-ray than small throughput with emission.On the contrary, with the visual angle corresponding to long path (for example from the shoulder to the shoulder), launching site 70 can be activated and have the X-ray of higher flux with emission.Similarly, for the path of centre, can suitably regulate the flux of the X-ray of being launched.In addition, the flux relevant with the position, visual angle can dynamically be regulated, because the patient moves through the CT scan device linearly.By this way, when allowing dynamic adjustments with the consistance of the signal that keeps detecting device 22 places, the effect of butterfly filter disc can be replicated.In addition, the flux of the corresponding X-ray of scalable focal spot and viewpoint so that to the radiation dose of responsive organ minimize and the optimization area-of-interest in image noise.
Present technique also can allow to use various detector technologies (for example energy range divides detecting device), so that can carry out CT technology (for example energy is distinguished CT).Because planar and/or vertically go up less detector size, so implement the material benefit more of this foreign technology.Similarly, this detecting device also can be easier to make to adapt to the detector size that reduce relevant with present technique.In addition, less segment angle relevant with present technique and cone angle have reduced the scattering in the measurement of X-transmitted intensity and can allow to save anti-scattering resistant grating from detecting devices, thereby increase detector efficiency.
The various physical arrangements of the source launching site 70 in x and z dimension and the detecting device 22 that is suitable for using have been narrated in the discussion of front in imaging system.In certain embodiments, can come operation issue point 70 and/or (a plurality of) detecting device 22 according to the one or more orders or the instruction sequence of some operating parameter that defines each launching site (being focal spot) and/or detecting device respectively.For example, command sequence definable focal spot be activated order, each focal spot of (promptly luminous) luminous the duration, the luminous energy of each launching site 70, with focal spot activate relevant mA, focal spots activation the duration or the like.Like this, given command sequence definable focal spot light-emitting mode does not wherein have focal spot simultaneously luminous, and some focal spots are simultaneously luminous, and some focal spots are luminous more frequent or more not frequent than other focal spots, and/or are used for the sequential or non-sequential sequence of light of focal spot.By this way, can select command sequence, it reaches some target, for example minimizes the heart overscanning, minimizes the spiral fashion overscanning, improves picture quality, reduces noise, reduces scattering, reduces heat, restriction patient dose of X-ray source or the like.In certain embodiments, for given patient, can scan (scout scan) (scanning of for example using the standing order sequence to use the butterfly filter disc of standard to obtain) based on initial alignment and calculate the appropriate command sequence.Just as will be understood, as inquiring into about Fig. 1, the instruction of the various command sequence of Tan Taoing here can be stored in also can be from wherein visit in the suitable sequence buffer 32.As selection, command sequence can by especially or " hastily " calculate, for example use close-loop feedback based on detectors measure.
About the command sequence of following discussion, and with reference now to Figure 14, z to focal spot series by the alphabet sequence mark, i.e. A, B, C, x to focal spot series then numbered promptly 1 to 20.In described example, and as following more detailed discussion, outside focal spot 64 can be corresponding with the peripheral radiation visual field among some embodiment.Equally, inner focal spot 66 can be corresponding with inner circular visual field (for example core visual field among some embodiment).
Consider above-mentioned UNC, described the continuous activation sequence of standard that is used for upwards having the distributed source of discrete focal spot at x and z.In this example, distributed X-ray source is the focus as 3 * 20 arrays depicted in figure 13.Can activate this distributed x-ray source by the command sequence that is stored in the sequence buffer (for example sequence buffer 32 of Fig. 1) sequentially.This serial command sequence can be corresponding to activation sequence, for example: A1-A2-A3-...-A20-B1-B2-B3-...-B20-C1-C2-C3-...-C20-A1-A2-A3-...-A20-... or the like.As selection, another example of serial command sequence can be A1-B1-C1-A2-B2-C2-A3-...-A20-B20-C20-A1-B1-C1-A2-... or the like.Like this, in these examples, launching site activates and can be undertaken by row or column is sequential.In other example, can use alternative pattern, for example spiral pattern, zigzag pattern, pseudo random pattern etc.In these continuous examples, have fixing or predetermined order and activate sequentially based on this fixing predetermined order.
In other embodiments, command sequence can be heterogeneous.In some such embodiment, comparable other focal spot of some focal spot is luminous more continually promptly to be activated.For example, the focal spot of the area-of-interest by requiring excellent picture quality luminous height decay part by patient or object and/or luminous can luminously more continually (replace adopting higher mA, kW and/or residence time luminous or except adopting higher mA, outside kW and/or residence time are luminous).On the contrary, focal spot by responsive organ luminous low decay part by patient or object and/or luminous can more not luminously (replace the lower mA of employing, kW and/or residence time luminous or except adopting lower mA, outside kW and/or residence time are luminous).An example of this heterogeneity command sequence can comprise all focal spots of activating distributed X-ray source (A1-〉C20) sequentially, activate subsequently only sequentially inner focal spot 66 (A6-〉A15, B6-〉B15, C6-〉C15) and repeat these corresponding command sequences.Like this, in this example, the frequency that inner focal spot 66 is activated is the twice of outside focal spot 64.In another example, some focal spots can not be activated.For example, in only to the interested enforcement of the sub-fraction of patient or object, can only activate inner focal spot 66 (A6-〉A15, B6-〉B15, C6-〉C15).As it will be appreciated that ground, also can use other combination of luminous (or non-luminous) focal spot, so that different focal spots or focal spot subclass more frequently or more are not activated continually than other focal spot or focal spot subclass.
In another embodiment, two or more focal spots can be activated simultaneously.Produce on the different piece that incides detecting device 22 at the focal spot that activated simultaneously or incide under the situation of the X ray on the different detecting device 22, this embodiment may be useful.For example, can be at the focal spot relevant with C of calibration on the z direction so that each row focal spot be luminous on the different longitudinal portions of detecting device 22 with row A, thereby make that if the focal spot on row A and the C is activated simultaneously, very little overlapping is then arranged or does not have to overlap on detecting device 22.In this example, the focal spot among row A and the C can be activated simultaneously, for example according to this command sequence:
A1C1-B1-A2C2-B2-A3C3-B3-...-A20C20-B20-A1C1-B1...。
In the enforcement of using more than a detecting device 22, for example depicted in figure 4, the adjustable focal spot is so that they are only by a detection in the available detecting device 22.In this was implemented, the focal spot that is calibrated to illuminate a detecting device 22 can activate simultaneously with the focal spot that is calibrated to illuminate different detecting device 22.By using two or more less detecting devices by this way, can obtain the bigger flux of the detecting device in single, big zone, allow simultaneously to manage and alleviate bigger synthetic scattering in the mode of the tissue (anatomy) that is suitable for being scanned or object.
In this embodiment that uses the focal spot that activates simultaneously, can produce additional cross scatter.Like this, can be based on the object that stands imaging, the desired path of passing object of each focal spot (because long path is corresponding with bigger scattering potential (scatter potential) usually), the position of each focal spot is (optionally to avoid activating following focal spot simultaneously, the X-ray of these focal spots too closely incides on a detecting device or a plurality of detecting device each other), the detectable signal (optionally to avoid activating following focal spot simultaneously, these focal spots have big difference aspect the desired detectable signal) that each focal spot is desired and making about whether activating the decision of focal spot simultaneously.In certain embodiments, the focal spot that can select its desired path to equate basically is used for activating simultaneously.If path has essential difference, then can adopt lower mA to activate to have less path (with therefore, lower decay) focal spot so that the main flux that receives equate and reduce to have reception than the cross scatter in the detecting device of low signal.
In addition, in certain embodiments, during given " sampling period " or activation interval, can in certain part in this cycle, activate a focal spot and in the different cycles, activate another focal spot, this different cycle can overlap or can not overlap with the cycle very first time in time, and promptly focal spot can have additional residence time.Just have net (net) cross scatter, this can be by own rather than directly measure in the unlatching source simultaneously with another by it once in a while.
In addition, can construct the command sequence that alleviates motion artifacts in certain embodiments.For example, because coronary vasodilator moves along the y axle in the xy plane mostly, so the focus of aiming at direction of motion will experience minimum motion.Like this, the command sequence of the focus of aiming at the structure in moving by the frequency that increase to activate or residence time reactivation can be used for making the minimum motion artifacts in the image of reconstruct.
In addition, in certain embodiments, can use the focal spot of different size or size (scale), because the focal spot of different size is more suitable for carrying out imaging in the structure to different size.For example, in the enforcement of heart, can use the command sequence of the little focal spot of reactivation (it covers the minor structure in the area-of-interest, for example coronary vasodilator).
Usually can activate the sequence aspect of each focal spot therein, whether activate simultaneously focal spot aspect, aspect absolute mA that each focal spot is associated, aspect relative mA that the focal spot that activates simultaneously is associated and have dirigibility aspect the additional residence time that provides for each focal spot.As an alternative, if at detecting device or reading horizontal (about this reading horizontal, produce detected X-ray from focal spot) go up to exist and obscure, promptly as long as do not overlap at (a plurality of) detecting device place, these various factorss can change on indivedual focal spot levels or with respect to some or all of focal spots.In fact, in certain embodiments, the available selected command sequence that is provided at balance desired between sampling, dose efficiency, scattering, image noise, temporal resolution and the spatial resolution is carried out the detailed assessment of possible subsequence or sequence.
Except the heterogeneity command sequence of focus, can use other command sequence that is suitable for solving heart half scanned scanning problem.In traditional third generation CT system, " half scanning " by 180 °+α rotation at interval (wherein α is the fan angle, its can be the physics fan angle of X-beam or corresponding to the fan angle of interested visual field) constitute.The data set that obtains in half scanning of rotation generally is rearranged for the collection that obtains corresponding to parallel beam or by the appearance reconstruct according to Parker's method of weighting.Compare with the parallel beam collection, the extra rotation that surpasses the fan angle can cause the patient that is scanned or the additional dosage of object.For example, with reference to Figure 15, described the view of prior art with r-θ coordinate, this view has described to use the useful data for projection 80 that half scanning collecting method obtains and the dosage 82 of waste, and wherein r be to be angle with respect to the ray of Z-axis with respect to the distance of the ray of isocenter (isocenter) and θ.
Inquire into as this paper, use distributed X-ray source and suitable Activiation method can reduce the waste dosage relevant with half scanning collection.For example, in one embodiment, the scope of the focal spot of activation (being launching site) can little by little be expanded the focal spot into rotation in 180 ° of parallel beam scopes (perhaps 90 ° in the enforcement of two detecting devices, in the enforcement of three detecting devices 60 ° etc.).When X-ray source during in interested parallel beam scope inner rotary, focal spot can be by little by little deactivation.Go to Figure 16 now, described r-θ coordinate diagram, this figure has illustrated the useful data relevant with present technique and the dosage of waste.As seeing in Figure 15 and 16, the waste dosage relevant with the technology of this example is reduced with respect to half traditional scanning collection technology.
Similarly, in the spiral fashion scan pattern, some x-ray doses can be wasted at the edge of helix.When by activate gradually and the deactivation focal spot (along with x to opposite z to) activation scheme when controlling, the distributed source topology can be avoided this waste dosage, because they enter interested longitudinal region and come out from interested longitudinal region.By this way, spiral fashion overscanning problem can be resolved.
In addition, being stored in order in the sequence buffer can each X-ray pulse of optimization and the detecting device timing of reading, thereby makes that corresponding the measurement is arranged in the r-θ space (radon space) well, is used for data rearrangement or image reconstruction efficiently.
In the command sequence that realizes being stored in the sequence buffer 32, can consider external information (for example ECG sequence).For example, in the gating of expection was gathered, the ECG signal can be used for determining when heart is in the desired stage that is used for imaging.In such embodiments, the frame angle correlativity that has (part that for example wherein virtual butterfly filter disc is used as command sequence is realized) in the sequence of being provided at.Therefore, in this embodiment, the X-ray may not can be produced, until reaching half by impact damper, be instruction in the sequence buffer can shelf position and the ECG trigger be condition so that some instructions can not be implemented till desired condition begins to be satisfied.Similarly, relevant embodiment can use " JUMP " or " GOTO " order in the sequence of being stored, to set about carrying out one group of instruction when definite ECG trigger and/or shelf position are suitable.
As selection, can be with the form of instruction to being stored in method like the DAS implementation of class in the sequence buffer 32.For example, can with the instruction in the circulation pattern sequence of operation impact damper and this instruction can be in proper order by and do not carry out, till desired frame angle and/or ECG trigger take place.At this moment, promptly when acquisition condition satisfies, will send " Exposure On " order and, the logic that is stored in when next ultraphotic figure begins in the sequence buffer will begin normal execution.
Like this, can be relevant as the order of command sequence storage or instruction or be correlated with the operation of DAS36 with the control of the operation of distributed X-ray source and X-ray controller 30.For example, can be provided as the part of the instruction column on the sequence buffer to the predetermined adjustment of data collection.In an example, when flux is low, may has electronic noise and benefit from long sub-view (DAS sampling interval).Like this, when when the instruction of the sequence buffer of X-ray controller 30 causes small throughput, corresponding instruction can be placed in the sequence buffer sampling interval with increase DAS36 in during small throughput.Similarly, when the two kVp of execution scanned, the order of switching kV also can be stored in the sequence buffer 32.
Technique effect of the present invention comprises that two or more discrete launching site of use and one or more relevant detection device are to carry out imaging to the visual field.The operation of two or more discrete launching site can be independently of one another.Can carry out the operation of each launching site and/or reading of detecting device according to the order that is stored in the sequence buffer.
This printed instructions uses example to come open the present invention, comprises optimal mode, and also makes any those skilled in the art can put into practice the present invention, comprises the method for making and using any equipment or system and carry out any merging.Scope of patent protection of the present invention is limited by claim, and can comprise thinkable other example of those skilled in the art.If these other examples have the structural detail as broad as long with the word language of claim, if perhaps these other examples comprise the structural detail that has the equivalence of unsubstantiality difference with the word language of claim, other such example is determined to be within the scope of claim.
The element tabulation
10 imaging systems
12 X-ray sources
14 collimators
16 radiation beams
18 patients
The decay part of 20 radiation
22 detectors
24 system controllers
26 gyrator systems
28 linear orientation subsystems
30 X-ray controllers
32 sequence buffers
34 motor controllers
36 data collecting systems (DAS)
38 computers
40 memories
42 operator workstations
44 displays
46 printers
48 PACS
60 flat-panel detectors
64 outside focal spots
66 inner focal spots
70 launching site
72 visual fields
74 first launching site
76 second launching site
80 interested central areas
82 outer peripheral areas
86 the 3rd launching site
88 the 4th launching site
90
92
94 launching site
96 launching site
98 launching site
100 CT scan devices
Claims (9)
1. a CT imaging system (10), it comprises:
A plurality of discrete X-ray emission focal spots (70);
One or more detecting devices (22), it is configured to detect the X-ray (16,20) by described a plurality of X-ray emission focal spots (70) emission;
X-ray controller (30), it is configured to operate independently described a plurality of discrete X-ray emission focal spot (70);
Data acquisition system (DAS) (36), it is configured to read output signal from described one or more detecting devices (22); And
Sequence buffer (32), it is configured to a row order of the operation of the storage described X-ray controller of control (30).
2. CT imaging system as claimed in claim 1 (10), wherein, described sequence buffer (32) further is configured to the secondary series order of the operation of the storage described data acquisition system (DAS) of control (36).
3. CT imaging system as claimed in claim 2 (10), wherein, described secondary series order comprises that the described data acquisition system (DAS) of one or more indications (36) is adjusted the sampling period, the beginning data are read or stops the order that data are read.
4. CT imaging system as claimed in claim 1 (10), wherein, described a plurality of discrete X-ray emission focal spots (70) are the part of distributed X-ray source (12).
5. CT imaging system as claimed in claim 1 (10), wherein, a described row order comprise one or more orders, these one or more orders indicate described X-ray controller (30) moment of appointment or with the sequence of appointment, with the mA of appointment, appointment the duration in, with the focal spot size of appointment, with the appointed interval after triggering, activate corresponding X-ray emission focal spot with the energy of appointment or with the kVp of appointment.
6. CT imaging system as claimed in claim 1 (10), wherein, each order in the described row order is corresponding with the operation at the X-ray emission focal spot at viewpoint place accordingly.
7. CT imaging system as claimed in claim 1 (10), wherein, from the different command definition of each X-ray emission of described a plurality of discrete X-ray emission focal spots (70) by a described row order.
8. method, it comprises:
Provide and comprise a plurality of discrete and distributed X-ray sources (12) of the X-ray emission focal spot (70) of operation discriminably;
The one or more detecting devices (22) that are configured to produce in response to the X-ray (16,20) by described distributed X-ray source (12) emission signal are provided;
Provide to store and be used to operate the sequence buffer (32) that one of described a plurality of X-ray emission focal spots (70) are listed as order;
X-ray controller (30) is electrically connected to described distributed X-ray source (12) and described sequence buffer (32), and wherein, described X-ray controller (30) can be operated described a plurality of X-ray emission focal spots (70) independently according to a described row order; With
Data acquisition system (DAS) (36) is electrically connected to described one or more detecting device (22), and wherein said data acquisition system (DAS) (36) can be read the signal that is produced by described one or more detecting devices (22).
9. method as claimed in claim 8 is wherein operated described data acquisition system (DAS) (36) according to a described row order.
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| US12/254,732 US7885375B2 (en) | 2004-02-27 | 2008-10-20 | Method and system for X-ray imaging |
| US12/254732 | 2008-10-20 |
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| CN102551783A (en) * | 2012-02-16 | 2012-07-11 | 邓敏 | Bi-modal real-time imaging device for surgery, system and method thereof |
| CN104545978A (en) * | 2015-01-20 | 2015-04-29 | 董桂青 | Filter for CT machine |
| CN104545963A (en) * | 2013-10-11 | 2015-04-29 | 中国科学院深圳先进技术研究院 | Adjacent dual-X-ray source CT imaging system and application thereof |
| CN106132302A (en) * | 2013-11-06 | 2016-11-16 | 射线科学有限公司 | X-ray imaging equipment including multiple x-ray sources |
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2009
- 2009-10-08 JP JP2009233968A patent/JP5658449B2/en active Active
- 2009-10-20 CN CN200910174032A patent/CN101726501A/en active Pending
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| CN104545963A (en) * | 2013-10-11 | 2015-04-29 | 中国科学院深圳先进技术研究院 | Adjacent dual-X-ray source CT imaging system and application thereof |
| CN106132302A (en) * | 2013-11-06 | 2016-11-16 | 射线科学有限公司 | X-ray imaging equipment including multiple x-ray sources |
| CN104545978A (en) * | 2015-01-20 | 2015-04-29 | 董桂青 | Filter for CT machine |
| CN109561865A (en) * | 2016-08-08 | 2019-04-02 | 昂达博思有限公司 | It is a kind of that X-ray is overlapped to rebuild the method and system of 3-D image by space-time |
| CN109561865B (en) * | 2016-08-08 | 2023-09-12 | 昂达博思有限公司 | Method and system for reconstructing three-dimensional image by space-time overlapping X-rays |
| GB2568735A (en) * | 2017-11-25 | 2019-05-29 | Adaptix Ltd | An x-ray imaging system |
| CN110123352A (en) * | 2018-02-02 | 2019-08-16 | 西门子保健有限责任公司 | The determination based on spectral topology figure of imaging parameters |
| CN112971816A (en) * | 2019-12-13 | 2021-06-18 | 通用电气公司 | System and method for focus motion detection and correction |
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| Publication number | Publication date |
|---|---|
| JP2010094509A (en) | 2010-04-30 |
| JP5658449B2 (en) | 2015-01-28 |
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