CN100482168C - X-ray calculation tomographic scanner and x-ray detecting system - Google Patents
X-ray calculation tomographic scanner and x-ray detecting system Download PDFInfo
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- CN100482168C CN100482168C CNB2004100978773A CN200410097877A CN100482168C CN 100482168 C CN100482168 C CN 100482168C CN B2004100978773 A CNB2004100978773 A CN B2004100978773A CN 200410097877 A CN200410097877 A CN 200410097877A CN 100482168 C CN100482168 C CN 100482168C
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Abstract
The present invention provide a kind of X-ray detection system, which includes one detector for detecting X-ray passing through inspected body and generating analog electric signal corresponding to the X-ray for each channel; one data acquisition unit comprising several circuit modules with circuits in the number corresponding to the channel number to convert the analog signals into digital signal for output; and one phase control unit for controlling the phase the circuit modules in the data acquisition unit and dividing the circuit modules into several groups operating synchronously with the clock signal possessing different phases in different groups.
Description
Technical field
The present invention relates to X-ray calculation tomographic scanner and X-ray detecting system, more particularly, relate to following X-ray calculation tomographic scanner and X-ray detecting system, wherein solved because the problem that the fluctuation of noise among detector or the DAS or running voltage causes has obtained stable and operation reliably whereby.
Background technology
X-ray calculation tomographic scanner (hereinafter being called X-ray CT scanner) is known to be a kind of computed tomographic apparatus.For a long time, X-ray CT scanner has been widely used as the instrument of medical diagnosis and various medical research work.Since it occurred, X-ray CT scanner had had very big development and has still developed.
The X-ray scanner of early stage type once is merely able to obtain the single section of image, therefore is difficult to obtain at short notice to be examined the great amount of images section of body on a large scale.Therefore, in the medical application of reality, be starved of a kind of technology, can obtain to be examined a large amount of high-definition picture sections of body on a large scale at short notice.
In order to satisfy above-mentioned needs, developed many section X-ray CT scanner recently and popularized.In many section X-ray CT scanner, use two-way detector array, the detector element row of given number (for example 4 or 8) wherein on direction, have been arranged perpendicular to row, wherein each row all is similar to the detector element linear array that uses in single section C-ray CT scanner, so two-way detector array comprises the segmental detector element of M passage (channel) xN (segment) (wherein M and N are positive integers) altogether.Data-acquisition system (DAS) connects the outfan of 2 dimension detector arrays.
Many section X-ray CT scanner comprise the X-ray source that is used to launch the X-ray beam, and this beam is fanning in being parallel to the plane of slice direction, also comprises 2 dimension detector arrays of the above-mentioned type.Pass the projecting image data that can once be obtained a plurality of sections by the conical beam X-ray of the body of 2 dimension detector array testing technologies (having visual field FOV effective diameter) by detection.Therefore, cut into slices more X-ray CT scanner can obtain than single section X-ray CT scanner more more number have a more high-resolution image.
2 dimension detector arrays comprise flasher, photodiode and cmos switch array.The X-ray that incides on the flasher is converted into optical signal, and it incides photodiode array and is converted into 2 each segmental analog electrical signal of dimension array.Each segmental signal of telecommunication is transferred to DAS by the respective switch element of cmos switch array.According to given number along detector element row on the slice direction, the cmos switch array will be combined from the signal of telecommunication that the photodiode array element of every group of detector element top is exported, and wherein every group of detector element comprises all that on slice direction the detector element of given number is listed as.
DAS is the device that comprises the analog-digital conversion element (DAS circuit part) with array format, is used to amplify from the analog detection signal of 2 dimension detector array received and with it be transformed into digital signal.Final digital signal is used for the carries out image reconstruction process.
The open No.2001-215281 of the uncensored patent application of Japan discloses a kind of detection system, it mainly comprises 2 dimension detector array and DAS, they are to described above similar and arranged by 3 dimension ground, thereby photodiode array and cmos switch array are disposed on the surface of bilateral circuit board, and DAS is disposed on another surface.In this detection system, thereby arrange that on photodiode array the flasher module makes their optical coupling each other.In practice, above-mentioned part is combined on the module-module basis (block-by-block basis), and wherein each module is assigned with the passage of given number.In typical X-ray CT scanner, DAS has high circuit complexity (complexity) usually to handle a large amount of passages, for example from 500 to several ten thousand passages.In order to reduce the difficulty that so a large amount of parts directly is combined into single, handle tens for each and all prepare a circuit board to the module of a hundreds of passage, and partly form detecting module by photodiode placed array, cmos switch array and DAS, be used to handle the dedicated tunnel that is positioned on any side of circuit board.A plurality of detecting modules are arranged on the part surface of a ball abreast.
In this detection system, electric power is fed to all detector modules from single power supply by cable.
DAS handles little electric current.Invaded the noise jamming of DAS by grounded part for fear of the little electric current of DAS processing, the basic framework of the ground wire of DAS circuit and X-ray CT scanner (base frame) insulation, perhaps, if ground wire links to each other with basic framework, then this connection only is present in a bit.In any case, the strong connection between the ground wire that avoid the DAS circuit and the basic framework.The entire circuit of DAS and single oscillator synchronization work.
Above-mentioned traditional detection system has many open questions.
First an open question relates to the grouping of DAS.Because the ground wire of DAS circuit basically with basic framework insulation, so when the entire circuit of DAS was worked with single oscillator synchronization, the ground connection level of DAS can fluctuate, and causes the ground wire of DAS to make a noise, thereby cause the image quality deterioration.
In addition, insulating ground wire causes second problem, i.e. the fluctuation of DAS ground connection level can influence the work of analogue signal.
Another problem is that the cable that supplies power to detection system exists voltage drop.The size of voltage drop changes pro rata with the length of cable, so the voltage drop difference of each detector module, because the cable length difference of each detector module.This causes in the detector module operating characteristic of DAS inhomogeneous.A kind of possible difference of passing through to reduce supply voltage between the detector module makes the operating characteristic of DAS part obtain the technology of enough good homogeneous, and being increases the cable size from power supply to each detector module on demand so that the voltage drop of cable is reduced to enough low level.Another kind of technology is that the length setting with every from power supply to each detector module cable is the length that equals from the power supply to the position the longest cable of detector module farthest.Yet the space that two kinds of technology all cause arranging detection system unacceptably increases, and therefore two kinds of technology all can not actually be dealt with problems.
Summary of the invention
Consider the problems referred to above, first target of the present invention is to reduce because the ground voltage that the clock synchronisation operation of each detector module DAS part causes and the fluctuation of supply voltage, realizes the steady operation of X-ray detecting system whereby.
Another target of the present invention is by a kind of power line that is arranged in the less space supply voltage to be fed to a plurality of detector modules, thereby the difference of the supply voltage between a plurality of detector modules is reduced to admissible scope.
In a scheme, in order to obtain first target, the invention provides a kind of X-ray detecting system, comprising: detector, this detector are surveyed by the X-ray that is examined body and are the analog electrical signal of each passage generation corresponding to the X-ray; Data capture unit, it comprises a plurality of circuit modules with analogue-to-digital converters, each circuit module all comprises the circuit identical with the number of active lanes of distributing to each module, and this data capture unit will be by converting the digital signal of described each passage and the digital signal of output conversion from the analog electrical signal of detector output to the corresponding analogue-to-digital converters of each passage; And phase control unit, the phase place of the circuit module of this phase control unit control data acquiring unit, described a plurality of circuit modules are divided into a plurality of groups, and the operation of respectively organizing circuit module is synchronous with the clock signal that is used for analogue-to-digital converters, and the phase place of described clock signal is different mutually between two groups at least.
As an example, the phase place of phase control unit control data acquiring unit circuit module, thus circuit module is divided into two groups, and the operation of the two groups of circuit modules clock signal opposite with two phase places is synchronous.
And, as another example, phase control unit comprises agitator and unit that is used to produce reference clock signal, it is used for the clock signal that agitator produces is directly offered at least one group of a plurality of circuit module groups, and will offer all the other groups of circuit module by the clock signal that makes the anti-phase generation of a plurality of clock signals that agitator produces.
And, as another example, phase control unit comprises and the same number of agitator of circuit module, is used to produce the reference clock signal that offers a plurality of circuit modules, and the reference clock signal that agitator produces is offered each circuit module independent and asynchronously.
In addition, as another example, phase control unit comprises and is used to produce the unit that reference clock signal also offers final reference clock signal each circuit module, wherein postpones the specific time each other between the reference clock signal.
In another scheme, in order to obtain second target, the invention provides a kind of X-ray detecting system, comprise a detector, it comprises a plurality of circuit modules of distributing to the passage of given number, being used to survey by the X-ray that is examined body also is that each passage produces the analog electrical signal corresponding to the X-ray, a data acquiring unit, it comprises the circuit module identical with the detector circuit number of modules, be used for and convert the digital signal of each passage to and to export final digital signal from the analog electrical signal of detector output, with a voltage regulator, it is arranged in each circuit module, and the supply voltage that is used for offering each circuit module is adjusted in specific magnitude of voltage.
And, as another embodiment, can provide plate shaped conductor, be used for supply voltage is offered each circuit module.
The present invention also provides a kind of X-ray calculation tomographic scanner, comprises the X-ray detecting system according to above-mentioned any one scheme, and data processing unit, and this data processing unit adopts the data reconstructed image that is obtained by the X-ray detecting system.
In X-ray calculation tomographic scanner according to the present invention and X-ray detecting system, the X-ray detecting system that forms has reduced because the radiation noise that the fluctuation of a plurality of detector module ground voltages causes, thereby has solved because the difference of operating characteristic between the detector module that the difference of supply voltage causes between the detector module.Therefore, in the operation of X-X-ray detection X, realized high stability and good uniformity, made the raising image quality become possibility whereby.In addition, also reduced the physical size of system.
Description of drawings
Fig. 1 schematically shows the block diagram of X-ray CT scanner according to an embodiment of the invention;
Fig. 2 is the block diagram that is illustrated schematically in the X-ray detecting system that uses in the X-ray CT scanner according to an embodiment of the invention;
Fig. 3 is arranged in the perspective view that a detecting module on the X-ray detecting system is seen from X-ray light incident side;
Fig. 4 is a perspective view that detecting module is seen from the back side that is arranged on the X-ray detecting system;
Fig. 5 is the sketch of layout that shows the X-X-ray detection X element of a detector module, and wherein this detector module is arranged in according to an embodiment of the invention in the employed X-ray detecting system of X-ray CT scanner;
Fig. 6 is the circuit diagram of the detector module of X-ray detecting system;
Fig. 7 schematically shows the sketch that DAS is divided into the mode of module;
Fig. 8 shows reference clock signal is offered circuit diagram according to the mode of the X-ray CT scanner X-ray detecting system of first embodiment;
Fig. 9 is the time limit figure that shows according to the reference clock signal of first embodiment, and the phase place of this reference clock signal is opposite each other;
Figure 10 shows the sketch that the mode of reference clock signal is provided according to the modification of first embodiment;
Figure 11 is the time limit figure that shows reference clock signal, and this clock signal has the decentralized photo according to the first embodiment modification;
Figure 12 shows the sketch that the mode of reference clock signal is provided according to another modification of first embodiment;
Figure 13 is the perspective view of a detector module, and this detecting module is arranged in the X-ray detecting system according to the X-ray CT scanner of second embodiment of the invention.
Figure 14 shows the block diagram that electric power is offered the mode of each detector module according to second embodiment;
Figure 15 shows to regulate the sketch of the mode of each detector module supply voltage according to second embodiment;
Figure 16 is the perspective view according to the X-ray CT scanner X-ray detecting system of third embodiment of the invention;
Figure 17 shows the sketch that the mode of electric power is provided with bonding jumper according to the 3rd embodiment; With
Figure 18 is the sketch that shows according to connect the mode of detector module by interconnection through the embodiment that revises.
The specific embodiment
Embodiment below with reference to connection with figures illustrates in greater detail the present invention.
First embodiment
Below with reference to Fig. 1-9 explanation first embodiment.
Fig. 1 has shown the many section X-ray CT scanner according to first embodiment of the invention.This many slice CT scanner not only can be carried out many slice helical scan, and can carry out traditional scanning (single section scanning and many section scanning).As shown in Figure 1, many slice CT scanner 10 comprises a bed (not shown), the body of examine (patient) is positioned on this bed, a basic frame G, it has the diagnosis chamber OP that is used to insert body P, is used to obtain projecting image data and data processing unit U of body P, be used to control the work of whole basic frame G, data for projection is reconstructed into image and shows final image.
This bed comprises upper flat plate, and it can alongst slide by bed driver element (not shown).In most of the cases, body P is placed with the length direction that the axis that makes body is parallel to bed.
Basis frame G comprises an X-ray tube 11 as the x-ray radiation source, its layout makes the body P that inserts among the diagnosis chamber OP between X-ray tube 11 and bed, an X-ray detector 12 that will be explained below, with an X-ray detecting system 14, it comprises data-acquisition system (DAS 13).In addition, basic frame G also comprises non-contact data buanch unit 15, bed driver element 16 and slip ring 17.
X-ray tube 11 and X-ray detecting system 14 (comprising X-ray detector 12 and DAS 13) are arranged on the rotating ring (rotating ring) 21, and rotating ring can be at basic frame G internal rotation under the control of bed driver element 16.That is to say that X-ray tube 11 and X-ray detecting system 14 rotate harmoniously around a rotating shaft, this rotating shaft is parallel to the body axis that is inserted in the body P in the basic frame G diagnosis chamber OP.Rotating ring 21 is with one week of per second or higher rotary speed rotation.
The patient body P of X-ray tube 11 in lying in visual field FOV effective diameter produces the X-ray of conical beam or fan-shaped beam.X-ray tube 11 produces the required electric power (tube voltage or tube current) of X-ray and provides by slip ring 17 from high tension generator 18.More clearly, X-ray tube 11 produces along the fan-shaped beam X-ray of the slice direction diffusion that is parallel to rotating shaft, perhaps along slice direction and perpendicular to the conical beam X-ray of the channel direction diffusion of slice direction.In most of the cases, body P lies on the appearing on the stage of bed along the length direction of bed, so slice direction is parallel to the axon of body P.
In the inside of basic frame G, collimator 19 is between X-ray tube 11 and body P.Collimator 19 will fashion into the X-radiation beam with particular beam size from the conical beam of the x-ray focus of X-ray tube 11 emission or the shape of fan-shaped beam X-ray.
Data processing unit U comprises the master controller 20 as key equipment, and further comprise and be used to carry out for example gauged pretreatment unit 22 of data of pretreatment, memory element 23, secondary storage 24, data processing unit 25, reconstruction unit 26, input equipment 27 and display unit 28, wherein these unit interconnect by data/control bus 29 each other.Bus 29 also connects external image blood processor 30.Image processing apparatus 30 comprises secondary storage 31, data processing unit 32, reconstruction unit 33 and input equipment 34, and display unit 35.
22 pairs of projected images that receive from non-contact data transfer unit 15 of pretreatment unit carry out sensitivity correction or the X-radiographic density is proofreaied and correct.After carrying out sensitivity correction or the correction of X-radiographic density, for example, be temporarily stored in memory element 23 at 1000 covers (1000 width of cloth), the 2 dimension projecting image datas that obtain on 360 ° by pretreatment unit 22.
Reconstruction unit 26 is kept at the section that the projecting image data in the memory element 23 produces (reconstruction) tomographic data according to fan-shaped beam method for reconstructing or conical beam method for reconstructing by reconstruction.
With reference to figure 2-6, explain X-ray detecting system 14 below according to present embodiment.
More clearly, as shown in Figure 2, X-X-ray detection X unit 14 comprises a plurality of (for example 38) detector module 14
1-14
nPower offers each detector module 14 from external power source 38 by cable 39
1-14
n
Each detecting module 14
n(usually use 14
nExpression) all comprises the detection channels of distributing to the given number of detector module in whole detection channels.In X-ray CT scanner, DAS 13 has 500 to several ten thousand passages altogether usually, and DAS 13 is divided into a plurality of modules, and each all comprises tens to a hundreds of passage.Each detector module 14
1-14
nThe X-X-ray detection X element that is arranged to make each module on channel direction along an arcuate alignment, and all X-X-ray detection X element forms X-ray incidence surface, this incidence surface is the form of spherical calotte, the focus that is centered close to X-ray tube 11 of this ball.Fig. 3 and 4 has shown 14
1-14
nIn the particular example of a detector modular structure.
Each detector module 14n has a rigid double-face printed circuit board (PCB) 141, with 142, photodiode arrays 143 of a cmos switch array (switch element array) and a flasher module 144, flasher module 144 with mode stacked on top of each other according to identical being disposed in order on a surface of printed circuit board (PCB) 141 of this paper explanation.Cmos switch array 142 and photodiode 143 are electrically connected to each other.Photodiode array 143 and 144 optical coupling of flasher module.Detector module 14
1-14
nThe combination of cmos switch array 142, photodiode array 143 and flasher module 144 formed X-ray detector 12 jointly.DAS circuit part 13a corresponding to the DAS 13 of each detector module 14n is arranged on the apparent surface of printed circuit 141.DAS circuit part 13a is electrically connected cmos switch array 142.Therefore, X-ray detector 12 and DAS are assembled by printed circuit 141 three-dimensionally.
Fig. 5 has shown the design (development) that detector module 14n sees from X-ray light incident side.Detector module 14n comprises a plurality of detector elements 1031 and 1032, and they are made up of flasher module 144 and photodiode array 143.These detector elements 1031 and 1032 are arranged that with the form of two-dimensional array its row and row extend along channel direction and slice direction respectively.
In the detector element 1031 and 1032, the felt width (sensible width) of each detector element 1031 on slice direction is 1.0mm, and the width felt on channel direction is 0.5mm.The felt width of each detector element 1032 on slice direction is 0.5mm, and the width felt on channel direction is 0.5mm.
Notice that the width felt of photodiode is by can sense value (sensible value) definite, this numerical value obtains when the rotating shaft of measured X-ray tube 11.Therefore, for example, the photodiode that can feel width and be 1mm is the photodiode that the width felt that records on the rotating shaft of X-ray tube equals 1mm.In particular cases dispersive at the X-ray, actually feel width equals to record on rotating shaft the width felt and multiply by a ratio, be i.e. the ratio of the distance put of the distance from x-ray focus to the photodiode physical location and rotating shaft from x-ray focus to the X-ray tube.That is to say that this to feel width be that the width felt of the photodiode of 1mm may be less times greater than 1mm, because the distance from x-ray focus to the photodiode physical location may be greater than the distance of putting to X-ray tube rotating shaft from x-ray focus.
Can feel width and be the detector element 1032 of 0.5mm arranges along slice direction to have the array formats that are measured as 16 row.The detector element 1031 that can feel width and be 1mm with the arranged in form of array two directly with can feel in detector element 1032 adjacent areas that width is 0.5mm, be that the column number (for example 12 row) that records on slice direction of each array of the detector element 1031 of 1mm is less than feeling the columns that width is detector element 1032 arrays of 0.5mm thereby can feel width.
In the present invention, the columns of detector element 1032 arrays that record along slice direction (being 16 row in this special case) is configured to the number (being 12 row during this is special) greater than any adjacent detector element 1031 arrays, and less than total columns (being 24 row in this special case) of detector element 1031 arrays.That is to say, in X-ray detector 12 according to the present invention, whole detector modules 14
1-14
nForm a two-way detector array, on channel direction, recorded 912 row, on slice direction, recorded 40 row.
Although in above-mentioned example, X-ray detector 12 has the detector element that is 2 dimension array formats layouts, pitch between its element and the element is that 0.5mm or 1.0mm change according to the width felt of detector element, but X-ray detector 12 also can equate to feel the form formation of the detector element of width with 2 dimension arrays with having.And the size of each detector element is not limited only to 0.5mm or 1.0mm, and other size for example 1.25mm also can adopt.2 analogue signals of tieing up the X-ray projection image that obtain by a large amount of X-ray detector elements 1031 and 1032 send to DAS 13 by cmos switch array 142.More clearly, X-ray projection image data send to DAS13 by cmos switch array 142, this DAS 13 comprises the data acquisition element (having for example 912 row and 8 or 4 row) of arranging with array format, and the number of its row is less than the columns (having for example 912 row and 40 row) of X-ray detector elements array.
During X-ray projection image data are transferred to the processing of DAS 13, under the control of master controller 20, cmos switch array 142 calculates the summation of the X-ray projection image data of specific columns on the slice direction, produces the 2 dimension projecting image datas that comprise specific columns whereby.DAS 13 is by a plurality of data acquisition element, and just, as the DAS circuit chip 13a formation of analogue-to-digital converters, DAS circuit chip 13a and X-ray detector 12 are 2 dimension array formats and arrange.In the DAS 13 that constitutes by this way, each data acquisition element is amplified the X-radiographic image data that is received, and converts thereof into digital form, produces the digital projection picture data whereby.Because X-radiographic image data addition on slice direction of specific columns, thus on the slice direction total columns of data acquisition element less than total columns of the X-ray detector elements of X-ray detector 12.
Make with the light transmission technology by noncontact buanch unit 15 from the numeral 2 dimension projecting image datas of DAS 13 output and to send to data processing unit U.Except the data transfer unit 15 of using the transmission of noncontact light, also can adopt the contact-type data transfer unit of using slip ring or analog.
During a rotation (1 second), use the exploration operation of X-ray detector 12 to be performed for example 1000 times.As a result, per second (1 changes) produces the 2 dimension projecting image datas that comprise M x N passage for 1000 times.In order to send the 2 dimension projecting image datas with big data size that produced with high data speeds non-time delay ground, DAS 13 and non-contact data buanch unit are with high speed operation.
In data processing unit U, the digital projection picture data that received are provided for pretreatment unit 22.The digital projection picture data were passed through pretreatment in pretreatment unit 22 after, final digital projection picture data were stored in the secondary storage 24, and by reconstruction unit 26 carries out image reconstruction process.As a result, obtained the X-ray scanning image of rebuilding.
Fig. 6 is the circuit block diagram of the X-ray detecting system 14 that makes up in the above described manner.DAS circuit part 13a to photodiode array chip 143, cmos switch array chip 142 and DAS 13 provides supply voltage, thereby provides supply voltage respectively for each detector module.
As mentioned above, X-ray detecting system 12 is made of a plurality of modules, and the module of DAS 13 is corresponding to the module of X-ray detecting system 12.Fig. 7 has schematically shown the module of DAS 13, and it comprises corresponding to each detector module 14
1-14
nDAS circuit 13
1-13
n(each all comprises DAS circuit part 13a).The integral body of DAS 13 can be obtained many passages, for example the data of 1000 passages (equaling along the number of the data acquisition element of channel direction layout).When DAS 13 comprises 10 modules, 13
1-13
nEach DAS circuit obtain the data of 100 passages.
In the present invention, two paths of the reference clock signal that is produced by single agitator 51 by as shown in Figure 8 offer DAS circuit 13
1-13
nMore clearly, the rectangle reference clock signal that agitator 51 produces is directly outputed to path A, and outputs to path B after signal is anti-phase by phase inverter 52.As a result, as shown in Figure 9, the phase place of the reference clock signal that provides by path A is opposite with the reference clock signal that provides by path B.
DAS circuit 13
1-13
nBe grouped, thereby offered DAS circuit 13 by commonage by the reference clock signal that path A provides
1, 13
3And other odd positions, and offered DAS circuit 13 by commonage by the reference clock signal that path B provides
2, 13
4With other even number positions.Each DAS circuit is all synchronously carried out analog-digital conversion with the reference clock signal of being given.
As mentioned above, in the scan operation of X-ray CT scanner used according to the invention, surveyed by X-ray detecting system 14 by the X-ray of body, and by rebuild X-ray CT image from the projecting image data of X-ray detecting system 14 outputs.In the detection of X-ray, the DAS circuit 13 of the DAS 13 of X-ray detecting system 14
1-13
nReference clock signal drives with opposite phase.This makes in the DAS 13 because the radiation noise that the fluctuation of power ground voltage causes is eliminated basically fully.Therefore, noise is weakened, thereby can obtain high-quality X-ray CT image.
Can be according to the mode that reference clock signal is offered DAS 13 of first embodiment by differently correct, as mentioned below.
First modification is shown in Figure 10 and 11.In modification as shown in figure 10, prepared DAS circuit 13 with chain DAS 13
1-13
nThe same number of agitator 51
1-51
n, and from agitator 51
1-51
nThe reference clock signal of output is offered each DAS circuit 13 respectively
1-13
nTherefore, as shown in figure 11, DAS circuit 13
1-13
nSynchronously work with each reference clock signal independent of each other.Note DAS circuit 13
1-13
nWork be synchronous because each DAS circuit is all synchronously worked with reference clock signal independent of each other respectively.This makes DAS circuit 13
1-13
nThe ground voltage or the fluctuation of supply voltage disperseed or be eliminated basically.Therefore, weaken the radiation noise, thereby can obtain high-quality X-ray CT image.
Second modification as shown in figure 12.In second modification, as shown in figure 12, the reference clock signal that is produced by single agitator 51 is by each delay circuit 53
1-53
N-1Postpone regular time in turn.The DAS circuit 13 of DAS 13
1-13
nBe not divided into and delay circuit 53
1-53
nThe same number of group, from agitator 51 and each delay circuit 53
1-53
nThe reference clock signal of output is provided for each DAS circuit bank.In this modification, the reference clock signal that postpones the set time each other can only produce with an agitator 51.This makes the fluctuation of ground voltage or supply voltage be disperseed or is eliminated basically.Therefore, weaken the radiation noise, thereby can obtain high-quality X-ray CT image.
Second embodiment
Below with reference to Figure 13-15 explanation second embodiment of the present invention.
Second embodiment relates to the technology of regulating the voltage of each detector module 14n of X-ray detecting system 14 in the X-ray CT scanner.According to the X-ray CT scanner of second embodiment substantially to similar according to the scanner of above-mentioned first embodiment.Represent with similar reference numerals to part similar among first embodiment, and no longer repeat specification herein.
In a second embodiment, as shown in figure 13, each detector module 14n has a power connector 61 and voltage regulators that are positioned at the printed circuit board (PCB) 141 lip-deep DAS of facing.As shown in figure 14, the power connector 61 of each detector module 14n is connected with the outfan of power supply 63 by cable 64, thereby by power connector 61 electric power is offered voltage regulator 62.
Therefore, in any one detector module 14n, voltage regulator 62 receives the input voltage (for example 6V) greater than particular value V1, and input voltage regulation (reductions) is arrived specific voltage V1 (for example 5V).
In X-ray detecting system 14 according to present embodiment, as mentioned above, although voltage drop different (for example differing about 0.1V-0.5V) in detector module 14n along cable 64, but the supply voltage that in fact is provided to each detector module 14n is adjusted in particular value V1, and does not consider the amount of voltage drop.
Therefore, whole DAS circuit part 13a of all detector modules work under identical voltage.This elimination or reduced because the difference of the analog-digital conversion characteristic that the difference of detecting module supply voltage causes.As a result, on all detector modules, obtained uniform X-X-ray detection X characteristic, thereby obtained high overall performance.
The 3rd embodiment
Below with reference to the Figure 16 and the 17 explanation third embodiment of the present invention.
The 3rd embodiment relates to the power line structure of X-ray detecting system 14 each detector module 14n in the X-ray CT scanner.Except power line structure, according to the X-ray CT scanner of second embodiment basically to similar according to the scanner of above-mentioned first embodiment.
In the X-ray detecting system 14 according to present embodiment, as shown in figure 16, the power line that will (just) supply voltage offers each detector module 14n is made of plate shaped bonding jumper 71.More clearly, supply voltage offers X-ray detecting system 14 from power supply 72 by cable 73, further offers each detector module 14n in the X-ray detecting system 14 by bonding jumper 71.As shown in figure 17, bonding jumper 71 has the 71a of branch, and its end is electrically connected the special part of each detector module 14n with screw or adapter.
Use bonding jumper 71 to make supply voltage because the change of the voltage drop that the position of detector module 14n causes minimizes, thereby the difference of supply voltage in the detector module has been reduced to low-down level as power line.As a result, in exploration operation, obtain high stability, thereby can obtain high quality image.In addition, do not need to use large-diameter cable, might reduce the space that is used to arrange power line in the X-ray detecting system 14, thereby might reduce the overall size of X-ray detecting system 14.
In order to prevent that X-ray detecting system 14 is subjected to the influence of the noise that illustrates among first embodiment, the interconnection of detector module 14n can be done following adjustment among the DAS 13.In interconnection structure shown in Figure 180, detecting module 14n adjacent one another are on channel direction links to each other by modular connector 81 each other.According to the type of X-ray detecting system 14, except being used for also needing to be used for sending the interconnection of data at detecting module 14n as the DAM chip interconnection of analogue-to-digital converters IC (for example being used for the interconnection of 16 IC).
In this example, as shown in figure 18, expectation is used for the interconnection of the DAM chip 82 of Analog signals and arranges discretely with the interconnection 83 that is used to send numerical data.In example shown in Figure 180, interconnection 83 is arranged in the center (seeing along slice direction) of each detecting module 14n, and DAM chip 82 is arranged in along the slice direction and the 83 adjacent two side areas that interconnect.This has reduced the interference from interconnection 83 noise, and wherein digital signal is by the 83 DAM chips 82 that send to Analog signals that interconnect.As a result, the standard deviation that might prevent the image noise measurement result worsens.In addition, by with the DAM chip 82 of Analog signals along the slice direction 83 adjacent two side areas that are arranged in and interconnect, might prevent that DAM chip 82 is exposed to the X-ray, also might make the interconnection length minimum of DAM chip 82.
Although the special embodiment of top reference has illustrated the present invention, the present invention is not limited in those embodiment, but can carry out many modifications under the prerequisite that does not deviate from the scope of the invention.
For example, although in the above-described embodiments, X-ray CT scanner is assumed that present widely used rotation/rotation type, wherein X-ray tube and X-ray detecting system center on the body of being checked and rotate harmoniously, but the present invention also can use static/rotation type, wherein a large amount of detector elements is arranged in fixed position along a ring, and the body that has only the X-ray tube to center on to be checked rotation.
And, although in the above-described embodiment, the flasher that has fluorescent material by use at first is transformed into light with the X-ray, by using photo-electric conversion element, for example photodiode further is transformed into electric charge with light again, incident X-ray is transformed into electric charge indirectly, optical semiconductor electric conductance unit directly is transformed into electric charge with the X-ray but for example also can use, and just, produces electron-hole pair and make electronics and the hole moves to electrode in quasiconductor.
Further, although in the above-described embodiments, X-ray CT scanner has single X-ray tube, also can arrange many to X-ray tube and X-ray detecting system on rotating ring.That is to say that the present invention also can adopt multitube X-ray CT scanner.
Claims (8)
1. X-ray detecting system comprises:
Detector, this detector are surveyed by the X-ray that is examined body and are the analog electrical signal of each passage generation corresponding to the X-ray;
Data capture unit, it comprises a plurality of circuit modules with analogue-to-digital converters, each circuit module all comprises the circuit identical with the number of active lanes of distributing to each module, and this data capture unit will be by converting the digital signal of described each passage and the digital signal of output conversion from the analog electrical signal of detector output to the corresponding analogue-to-digital converters of each passage; With
Phase control unit, the phase place of the circuit module of this phase control unit control data acquiring unit, described a plurality of circuit modules are divided into a plurality of groups, and the operation of respectively organizing circuit module is synchronous with the clock signal that is used for analogue-to-digital converters, and the phase place of described clock signal is different mutually between two groups at least.
2. according to the X-ray detecting system of claim 1, wherein
The phase place of the circuit module in the phase control unit control data acquiring unit is divided into two groups with described a plurality of circuit modules, and opposite with two phase places respectively clock signal of the operation of these two group circuit modules is synchronous.
3. according to the X-ray detecting system of claim 1, wherein phase control unit comprises:
Agitator is used to produce reference clock signal; With
A unit, the clock signal that is used for that agitator is produced directly offer at least one groups of many group circuit modules, and the clock signal that will produce by the polarity inversion that makes the clock signal that agitator produces offers the circuit module of all the other groups.
4. according to the X-ray detecting system of claim 1, wherein
Phase control unit comprises and the same number of agitator of circuit module, is used to produce the reference clock signal that offers a plurality of circuit modules, and independently, asynchronously is offered each circuit module by the reference clock signal that agitator produces.
5. according to the X-ray detecting system of claim 1, wherein
Phase control unit comprises that each reference clock signal that is used to produce each reference clock signal of being delayed special time each other and will produces offers the unit of each circuit module.
6. according to the X-ray detecting system of claim 1, wherein
Detector is 2 dimension detectors, comprises one 2 dimension detector array, wherein each row be arranged in the vertical direction of slice direction on, the number of the detector element of arranging along channel direction that each row is comprised is identical with the number of passage,
This detector comprises: the flasher module for each detector element is arranged is used for the X-ray is transformed into optical signal; Photodiode array with the optical coupling of flasher module is used for and will be transformed into the signal of telecommunication from the optical signal of the flasher module output of each detector element; And a switch element array, the signal of telecommunication that the detector element photodiode that is used for listing along given number on the slice direction is exported combines.
7. according to the X-ray detecting system of claim 6, wherein
Photodiode array, switch element array and data capture unit are arranged by 3 dimension ground by circuit board.
8. X-ray calculation tomographic scanner comprises according to the X-ray detecting system of claim 1 and uses the data processing unit of the data reconstructed image that is obtained by this X-ray detecting system.
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| JP2008237886A (en) * | 2007-02-28 | 2008-10-09 | Toshiba Corp | X-ray ct device and method of controlling the same |
| US9689996B2 (en) * | 2013-04-05 | 2017-06-27 | General Electric Company | Integrated diode DAS detector |
| CN105890553A (en) * | 2016-04-08 | 2016-08-24 | 中国科学院等离子体物理研究所 | Nondestructive detection method by using X rays for online measuring torsion rate of superconducting cable |
| DE102016213379A1 (en) * | 2016-07-21 | 2018-01-25 | Siemens Healthcare Gmbh | Method for operating an X-ray device and associated X-ray device |
| JP6869914B2 (en) * | 2018-03-06 | 2021-05-12 | 富士フイルム株式会社 | Radiation image detector |
| CN109199427A (en) * | 2018-10-30 | 2019-01-15 | 江苏赛诺格兰医疗科技有限公司 | A kind of distributed high voltage supply framework for PET system |
| CN110702706B (en) * | 2019-09-20 | 2022-05-20 | 天津大学 | Method for simulating output data of energy spectrum CT system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4969095A (en) * | 1987-01-06 | 1990-11-06 | U.S. Philips Corporation | Scintillation camera having computer control of electrical signals indicating scintillations |
| EP1343024A1 (en) * | 2000-11-22 | 2003-09-10 | Kabushiki Kaisha Toshiba | Radiation image diagnostic system and radiation detector |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4969095A (en) * | 1987-01-06 | 1990-11-06 | U.S. Philips Corporation | Scintillation camera having computer control of electrical signals indicating scintillations |
| EP1343024A1 (en) * | 2000-11-22 | 2003-09-10 | Kabushiki Kaisha Toshiba | Radiation image diagnostic system and radiation detector |
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