CN102151140A - Improved computer tomography imaging for detecting examination object with sharp attenuation - Google Patents
Improved computer tomography imaging for detecting examination object with sharp attenuation Download PDFInfo
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Abstract
本发明涉及一种利用计算机断层造影系统(C1)采集检查对象的测量数据(p)以用于再现检查对象的图像数据(f)的方法。在射线源(C2，C4)围绕检查对象旋转期间作为投影采集测量数据。对检查对象的体素的图像数据(f)的测量数据采集发生在多次旋转期间。每一次旋转都采集非整数数量的投影，使得多次旋转的投影合并成整数数量的投影。例如这些针对一个体素的投影可以在两次相继的旋转期间被采集，其中每次旋转都采集半整数数量的投影。
The invention relates to a method for acquiring measurement data (p) of an examination object with a computed tomography system (C1) for reconstructing image data (f) of the examination object. The measurement data are acquired as projections during the rotation of the radiation source ( C2 , C4 ) around the examination object. The measurement data acquisition of the image data (f) of the voxels of the examination object takes place during a plurality of rotations. A non-integer number of projections are collected for each rotation, so that projections from multiple rotations are combined into an integer number of projections. For example, these projections for a voxel may be acquired during two successive rotations, with each rotation acquiring a half-integer number of projections.
Description
Technical field
The present invention relates to a kind of method that is used to utilize the computer-tomographic system collection to check the measurement data of object, wherein during checking the object rotation, gather this measurement data as projection at radiographic source.
Background technology
It generally is known utilizing the CT system to come the method for scanography object.Wherein for example adopt circular scan, have the order circular scan or the helical scanning of advance value.In these scannings, the detector that is arranged on the opposite by at least one x-ray source and at least one is taken the absorption data of checking object from different shooting angle, and is counted as the cross-sectional image of checking object by absorption data or the projection meter that corresponding reproducting method will be collected like this.
For the X ray CT data set according to computer tomograph (CT equipment) reproduces the CT (computer tomography) image, just reproduce the CT (computer tomography) image, adopt so-called filtered back-projection method (Filtered Back Projection as standard method at present according to the projection of being gathered; FBP).Developed more bothersome method recently, the reproducting method of iteration for example utilizes these methods can eliminate at least some restrictions among the conventional FBP.
If the quality of the CT image that assessment is reproduced, then noise is main parameter.This noise can be divided into quantum noise and electronic noise, and the latter is also referred to as detector noise.Quantum noise checks that by passing at the X ray by the x-ray source emission random fluctuation that scattering takes place in the object process and absorbing when causes.Although hit detector the X ray quantum random distribution that this causes existing consistent shooting situation also to have varying number.On the contrary, detector noise is the thermal noise in the detector, and this thermal noise is irrelevant with the quantity that drops on the quantum on the detector.Therefore, the electronic noise deal that accounts for whole noises is along with by the decline of the quantum quantity of detectors measure and rise.This is a special problem with the low quantum takeoff of x-ray source the time or when measuring the inspection object of strong attenuation.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of method of utilizing the computer-tomographic system collection to check the measurement data of object, and this method is devoted to reduce the component of electronic noise.In addition, also to provide the method that is used to reproduce the CT image accordingly, control corresponding and computing unit, CT system, computer program and computer program.
Utilize measurement data that the computer-tomographic system collection checks object being used for reproducing the method for the view data of checking object of the present invention, radiographic source during check the object rotation as the projection acquisition measurement data.During the measurement data acquisition of the view data of the voxel of checking object occurred in repeatedly rotation.The projection of non-integer number is all gathered in rotation each time, thereby the projection of repeatedly rotating is merged into the projection of integer amount.
For reproduced image, all should provide the projection of specific quantity to each voxel of checking object.Particular voxel be projected in radiographic source and be arranged between the detector on opposite, pass when connecting line that this voxel extends exists and can be gathered.In this case, this voxel is by X ray " irradiation " or transmission.In the method, data acquisition is carried out like this, i.e. this transmission not only exists in the once rotation of x-ray source, and exists in the repeatedly rotation of x-ray source.Therefore, reproduce each voxel is not only handled data from the single rotation, and handle from twice or the data of rotation repeatedly in order to carry out image.
For acquired projections, need particular time interval and/or specific angle advance value, this interval or angle advance value are identical to all projections.This interval or angle advance value can be selected as, and the quantity of collectable projection is not to draw integer in feasible each rotation.Therefore, if just begin acquired projections in when beginning rotation, then after next one rotation beginning, just finish on the collection of a projection.
The repeatedly rotation that each voxel all is used for image calculation is consistent mutually with the number of projections of each rotation: if the projection addition that will repeatedly rotate then obtains integer.Preferably, when the projection of repeatedly all rotations of rotation all just obtains integer during addition, therefore, when the projection of a small amount of rotation of an addition, can not obtain integer.
Particularly advantageously be that the position, angle of distributing to the once projection of rotation exists displacement with respect to the position, angle of the projection of rotation next time.Each projection is commonly referred to projected angle all corresponding to the position, angle of x-ray source.Interlocking of projected angle, all check new " view " object and that pass the inspection object corresponding to overlooking because have each projection of different projected angles corresponding to checking the better scanning of object.On the contrary, the projection with same projection angle does not provide so new view.
As preferred numerical example, can be to use the projection of twice circulation in conjunction with 1/2 integer amount, and the projection of using three rotations and 1/3 integer amount.Certainly can also be other combination, for example projection of 4 circulations and 1/4 integer amount, the projection of 5 circulations and 1/5 integer amount, or the like.
This method is particularly useful for the measurement data of taking less than the spiral CT of 1 pitch according to having.At this, pitch explanation to be used for carrying out the measurement data that image reproduces about specific picture point the how many times rotation will take place in order to gather.Interchangeable, can also be according to sequence C T shooting, collecting measurement data.
In embodiments of the present invention, check the inspection object that the ray that radiographic source is launched is carried out strong attenuation owing to its stretching, extension to liking.Its typical example is bulky patient.
Be used for reproduce checking the method for the view data of object in the present invention, gather measurement data in advance according to the method described above according to measurement data.To checking each voxel of object, all the projection separately with a plurality of rotations of carrying out continuously is combined into a data set.Reproduce the image value of this voxel according to this data set.
Description of drawings
Explain the present invention in detail by embodiment below.This:
Fig. 1 illustrates first sketch map of the embodiment of the computer-tomographic system with image reproduction block,
Fig. 2 illustrates second sketch map of the embodiment of the computer-tomographic system with image reproduction block,
Under the supposed situation that the CT that Fig. 3 is illustrated in does not have electronic noise takes when picture quality remains unchanged theoretic dosage reduce.
The specific embodiment
In Fig. 1, at first schematically show the first computer-tomographic system C1 with image-reproducing means C21.In rack shell C6, has support, the detector C 3 that the first X-ray tube C2 is set and is arranged on its opposite on this support in this unshowned sealing.Optionally, the detector C 5 that the second X-ray tube C4 is set and is arranged on its opposite in the CT system shown here, thereby can realize higher temporal resolution by the additional irradiator/detector combination that provides, perhaps in irradiator/detector system, also can carry out " dual energy " under the situation of use different x-ray energy spectrum and check.
In addition, the C1 of CT system also has patient's bed C8, the patient can be moved in the measurement field along the axle C9 of system (being also referred to as the Z axle) on this patient's bed when checking, wherein scanning itself can be used as and do not advance patient's pure circular scan only to carry out in interested inspection area.In this process, x-ray source C2 and C4 are respectively around patient's rotation.In x-ray source C2 and C4 opposite detector C 3 and C5 motion together concurrently, with the acquired projections measurement data, these projection measurement data are used to reproduction of sectional view then in this process.Replace wherein the patient is passing the sequential scanning of checking that the field is moved step by step between each time scanning, certainly can also carry out helical scanning, the patient is utilizing the scan period of the rotation that X ray carries out to move along the inspection field that the axle C9 of system is passed between X-ray tube C2 or C4 and detector C 3 or the C5 continuously in this helical scanning.Along the moving and the rotation of x-ray source C2 or C4 simultaneously of axle C9, under x-ray source C2 or C4 situation, during this measurement, producing helical orbit by the patient with respect to helical scanning the patient.This track can also realize in the following manner that promptly support moves along axle C9 under the situation that the patient does not move.
The projection measurement data p that is obtained by detector C 3 and C5 (below be also referred to as initial data) sends control and computing unit C10 to by initial data interface C23.These initial datas p is being further processed in image reproduction block C21 through after the appropriate pretreatment subsequently in case of necessity.Image reproduction block C21 in this embodiment in control and computing unit C10 with processor on the form realization of software, for example with one or more computer program code Prg
1To Prg
nForm.Reproduce as with reference to the control of measuring process being explained computer program code Prg about image
1To Prg
nBe also contained on the exterior storage medium and can be loaded into when needed control and computing unit C10 in.
Then, the view data f that reproduces by image reproduction block C21 be stored among the memorizer C22 of control and computing unit C10 and/or according to common mode output to control and the display screen of computing unit C10 on.They can also be input to the network that is connected with computer-tomographic system C1 by the unshowned interface of Fig. 1, for example in the radiology information system (RIS), and are stored in this system and export in the operational mass storage or as image.
Control and computing unit C10 additionally can also carry out the function of EKG, wherein use lead C12 to conduct the EKG electromotive force between patient and control and computing unit C10.In addition, the C1 of CT system shown in Figure 1 also has contrast medium injector C11, by this contrast medium injector can be in addition with radiography through injecting patient's blood circulation, thereby patient's blood vessel, the ventricle of especially dancing heart can be shown better.Also exist thus in addition and carry out the probability that perfusion is measured, the method that is proposed is equally applicable to perfusion and measures.
Fig. 2 illustrates C arc system, and wherein the CT system with Fig. 1 is different, shell C6 carrying C arc C7, and a side has been fixed X-ray tube C2 on this C arc, and opposite side is being fixed the detector C 3 on opposite.In order to scan, C arc C7 centers on the axle C9 of system deflection equally, thereby can scan from a plurality of scanning angles, and can determine the homolographic projection data p from a plurality of projection angles.The same control and the computing unit C10 that also has at the described type of Fig. 1 of the C arc C1 of system of Fig. 2 with the CT system of Fig. 1.
The present invention can use in two systems illustrated in figures 1 and 2.In addition, the present invention can be used for other CT system in principle, for example is used to have the CT system of the detector that forms a unbroken loop.
A kind of special challenge is to obtain fine in nature CT image under the situation that a small amount of X ray arrival detector is only arranged.This is especially true under bulky inspection object situation, just has under the situation of high attenuation at object.Because it is the quantity of overweight patient in Western industrialized economy is increased sharply, more and more important to the optimization of this patient group's CT examination.In general, when checking the obese patient, reach the power limit of x-ray source soon.That is to say, to have only a small amount of X ray quantum to arrive detector owing to enclosing of patient is long, because these X ray quantum are almost absorbed fully in patient's body although the power of x-ray source is the highest.Same problem also must exist during promptly so-called " low dose " checks to hang down the inspection that ray dosage carries out.Its example is a screening inspection, does not just have specifically to suspect the prevention inspection of disease, and perhaps follow-up (follow up) checks, i.e. inspection after finding disease, and it has the purpose that occurs and can treat this disease once more of timely this disease of identification.
Bed precession when in these cases, people attempt by longer support rotational time and the shooting of minimizing spiral comes accumulated dose.When spiral was taken, pitch was a parameter that does not have dimension, and this parameter is provided by the pitch of spiral curve.The pitch of this spiral curve is corresponding to the bed precession of each rotation and the ratio of detector width, just under the situation of multi-row detector with the ratio of the width that adds up of all detector line.Pitch less than 1 situation under, have eclipsed scanning, thereby image contributed more than the data of rotation once volume.Therefore, check that the voxel of object is penetrated by X ray during x-ray source repeatedly rotates, this X ray is detected by detector, just repeatedly is being arranged in FoV (visual field) during the rotation.Therefore can be used for being projected in the repeatedly circulation " having (stecken) " of image reproduction.For example, if select 0.5 pitch, then twice circulation projection is used to reproduce the image value of a picture point.
But by the described technology that is used for accumulated dose, can not avoid following principle matter when shooting has the object of high attenuation: each rotation all needs the projection of specific minimum number to be used for the image reproduction.In general, should provide 1000 projections at least, for example 1158.This is used to be avoided to occur scanning pseudo-shadow and along with the distance from center of rotation increases and strong row reduce definition.Can explain like this along with the strong row apart from increasing from center of rotation reduce definition, promptly must exist more projection to be used for the image reproduction than the voxel that is positioned at the center for being positioned at from the voxel at the far place of center of rotation.If do not have enough measured values at these voxels, just in measurement data, there be " space ", pseudo-shadow then can appear scanning.This scans pseudo-shadow can wherein for example produce the data that do not record by interpolation by smoothly filling up, but has reduced image definition thus.
The projection of this minimum number and support rotational time have been determined the Measuring Time of each projection, i.e. the so-called time of integration or persistent period of reading.For the obese patient, very rapidly just reached pad value, even wherein under the longest as far as possible situation of X-ray tube power maximum and support rotational time, also can only in the time of integration, measure a spot of quantum, make electronic noise surpass quantum noise and become main noise component in the CT image.At this, electronic noise is understood that the noise component(s) that quantity detector and measured X ray quantum has nothing to do.
Because the existence of electronic noise, limited CT to very obese patient's application on the one hand, patient for normal size just must apply more roentgendosis to reach specific picture noise on the other hand, has unnecessarily strengthened patient's radiation burden thus.Fig. 3 is illustrated in hope and eliminates fully under the situation of influence of electronic noise, and what change along with the patient's diameter DIA that with cm is unit for mode standard (time of integration of 215 μ s and the x-ray tube current of 500mA) is that the imaginary dosage of unit is saved SAV with %.Suppose specific picture noise respectively, and which component of check image noise to be can be regarded as electronic noise for this reason.If for example investigate the inspection object of 40cm diameter, be to have saved 70% dosage under 80kV and picture quality remains unchanged simultaneously the situation then at the accelerating potential of X-ray tube, the if there is no words of electronic noise.The shared deal of electronic noise rises along with the increase of patient's diameter DIA on the one hand in the entire image noise, because arrive the quantum minimizing of detector along with the increase of patient's diameter DIA.On the other hand, this deal reduces along with the accelerating potential of X-ray tube and rises, because X ray is absorbed more under situation more weak, more low-yield ray just.
The Measuring Time of each projection-just time of integration-prolongation, can reduce relative value's size of electronic noise and quantum noise, thereby under the situation of given decay, reduce picture noise.Therefore this is to be worth desired effects.But, simultaneously also reduced the quantity of the captured projection of each circulation thus, and be accompanied by that the pseudo-shadow of the scanning of explaining above of not expecting increases and along with the distance from center of rotation increases and reduces the effect of definition.
Considering under the situation of these understanding, is proposing a kind of scan pattern or image acquisition modality of correction of the object that is used to have high attenuation, wherein eclipsed helical scanning under the fine pith situation and obvious increased integration time are being combined.As mentioned above, the prolongation of the time of integration causes the number of projections of each rotation to reduce.This causes scanning, and pseudo-shadow increases and along with the distance from center of rotation increases and reduces the not desired effects of definition.In order to avoid these effects, the number of projections of pitch with each rotation is complementary.This coupling is carried out like this, and the projection of non-integer number is all taken in promptly each rotation.
At this, the number of projections of each rotation is understood that multiplying each other this quantity and the time of integration has just illustrated the once persistent period of rotation.Gathered during being projected in the x-ray source rotation, wherein each projection during the interval that equates with the time of integration is all counted the X ray quantum by detector.During this time of integration, the angle advance value that the x-ray source rotation is specific.If the projection of non-integer number is all gathered in each rotation, this means last being projected in during the current rotation, but will after ensuing rotation begins, just finish collection this projection not by complete collection.
As example, provide about 0.5 the pitch value (thereby twice circulation contributed to every image) and the combination of the half integral number of projections that at every turn circulates.(half integral quantity is understood that 0.5 number that finishes).Therefore can be at this roughly with half change of normally used number of projections of rotating at every turn; For example be 579.5 replace using always 1158.But this can use half integral arbitrarily number of projections under as 0.5 situation in pitch.Another example is to use the combination of the number of projections (for example 386.33 replace using always 1158) of about 0.33 pitch value (thereby every image is given in 3 rotation contributions) and each rotation 1/3 integer.(numeral of 1/3 integer is understood that 0.33 numeral that finishes).
Respectively importantly, the number of projections of each rotation is not an integer.The projection of integer amount will all just obtain under the situation of addition in all projections that the image that will conduce a voxel reproduces.
Each projection is assigned to specific position, support angle.Have for each rotation under the situation of 1158 projections, the distance between the position of adjacent projections approximately is 0.31 °.Therefore first projection is corresponding to 0 ° angle, thus second projection subsequently corresponding to 0.31 ° angle, ensuing the 3rd projection is corresponding to 0.62 ° angle, the rest may be inferred.If the projection of integer amount is used in each rotation, then to be distributed in when support rotates at every turn all be identical at these angles.On the contrary, if the projection of non-integer number is used in each rotation, then the projection of adjacent rotation is that displacement is arranged mutually with regard to their position, angle.Therefore, in the rotation of following mutually of the image value that contributes to a voxel, raster is interlaced on angle direction, thereby interlocking on the angle direction produces meticulousr raster by each eclipsed being rotated in.
For reproduced image, can the known method of employing own.But under the situation of using multi-row detector, just under situation about measuring with taper ray geometry, the pseudo-shadow of cone beam may appear.The pseudo-shadow of this cone beam can be avoided by the reproduction of adopting iteration, because cause that under the situation that iteration is reproduced the geometrical relationship of the pseudo-shadow of cone beam is taken into account calculating and has suffered.
By described prolongation, concerning the object (such as overweight patient) of strong attenuation, realized the better pictures quality by the electronic noise in the obvious minimizing image to the time of integration.Simultaneously, bring along with reducing number of projections simply in the prior art such as the pseudo-shadow of scanning and along with the distance from center of rotation increases and the shortcoming that reduces definition has strongly obtained avoiding, its method is to adopt the projection of less pitch in conjunction with non-integer number each rotation and this pitch-matched.
According to embodiment the present invention has been described.Should be appreciated that and to carry out countless changes and correction and can not depart from the scope of the present invention.Thereby certainly do not adopt described spiral to take and adopt sequence shooting with repeatedly rotation; Between each sequence is taken, relatively move in this case and check object and x-ray source, or take in cone of radiation and will check the relatively move part of detector width of object and x-ray source under the geometric situation corresponding to the width of detector.
Claims (15)
1. a measurement data (p) of utilizing computer-tomographic system (C1) collection inspection object is to be used to reproduce the method for the view data (f) of checking object, wherein at radiographic source (C2, C4) around checking during the object rotation as projection acquisition measurement data (p)
During the measurement data acquisition of the view data (f) of the voxel of checking object occurred in repeatedly rotation,
The projection of non-integer number is all gathered in rotation each time, makes the projection of repeatedly rotation be merged into the projection of integer amount.
2. method according to claim 1, there is displacement in the position, angle of wherein distributing to once the projection of rotation with respect to the position, angle of the projection of rotation next time.
3. according to the described method of one of claim 1 to 2, wherein said repeatedly rotation is twice circulation, and the projection of described non-integer number is the projection of half-integer quantity.
4. according to the described method of one of claim 1 to 2, wherein said repeatedly rotation is three circulations, and the projection of described non-integer number is the projection of 1/3 integer amount.
5. according to the described method of one of claim 1 to 4, wherein the collection of measurement data (p) is carried out according to having to take less than the spiral CT of 1 pitch.
6. according to the described method of one of claim 1 to 4, wherein the collection of measurement data (p) is taken according to sequence C T and carry out.
7. according to the described method of one of claim 1 to 6, wherein check to as if because its stretching, extension and (C2, C4) ray of being launched carries out the inspection object of strong attenuation to radiographic source.
8. a method that is used for reproducing according to measurement data (p) view data (f) of checking object is wherein gathered measurement data (p) according to the described method of one of claim 1 to 7,
Each voxel of checking object all is combined into a data set with the projection separately of a plurality of rotations of carrying out continuously,
Reproduce the image value of this voxel according to this data set.
9. a control unit (C10) that is used to control the measurement data acquisition of CT system (C1) comprises and is used for program code stored (Prg
1-Prg
n) program storage, wherein in this program storage, have the program code (Prg be used to carry out according to the method for one of claim 1 to 7
1-Prg
n).
10. a computing unit (C10) that is used for reproducing according to the measurement data (p) of CT system (C1) view data (f) of checking object comprises and is used for program code stored (Prg
1-Prg
n) program storage, wherein in this program storage, have the program code (Prg be used to carry out method according to Claim 8
1-Prg
n).
11. CT system (C1) that has according to the control unit and/or the computing unit (C10) of claim 9 and/or 10.
12. a computer program that is used to control the measurement data acquisition of CT system (1) has program code devices (Prg
1-Prg
n), be used for when this computer program moves on computers, controlling method according to one of claim 1 to 7.
13. one kind has program code devices (Prg
1-Prg
n) computer program, be used for when this computer program moves on computers carrying out method according to Claim 8.
14. a computer program, comprise the measurement data acquisition that is used to control CT system (C1) computer program can be on computer-readable data medium stored program code device (Prg
1-Prg
n), be used for when this computer program moves on computers producing to execution according to the method for one of claim 1 to 7.
15. a computer program, comprise computer program can be on computer-readable data medium stored program code device (Prg
1-Prg
n), be used for when this computer program moves on computers, carrying out method according to Claim 8.
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| DE102010005635.9A DE102010005635B4 (en) | 2010-01-25 | 2010-01-25 | Improved CT scans for investigation of severely debilitating subjects |
| DE102010005635.9 | 2010-01-25 |
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|---|---|---|---|---|
| CN104414675A (en) * | 2013-09-06 | 2015-03-18 | 西门子公司 | Method and x-ray system for dual-energy spectra ct scanning and image reconstruction |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5265142A (en) * | 1992-05-08 | 1993-11-23 | General Electric Company | Image reconstruction technique for a computer tomography system |
| CN1144032A (en) * | 1994-02-03 | 1997-02-26 | 模拟公司 | X-ray tomography system for and method of improving quality of scanned image |
| US20060018424A1 (en) * | 2004-07-01 | 2006-01-26 | Herbert Bruder | Method for detecting and visualizing dynamic processes in an object volume |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3227625A1 (en) * | 1982-07-23 | 1984-01-26 | Siemens AG, 1000 Berlin und 8000 München | Computer tomograph |
| JPS62221338A (en) | 1986-03-24 | 1987-09-29 | 横河メディカルシステム株式会社 | Scan data collection method in radiation tomographic imaging apparatus |
-
2010
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-
2011
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5265142A (en) * | 1992-05-08 | 1993-11-23 | General Electric Company | Image reconstruction technique for a computer tomography system |
| CN1144032A (en) * | 1994-02-03 | 1997-02-26 | 模拟公司 | X-ray tomography system for and method of improving quality of scanned image |
| US20060018424A1 (en) * | 2004-07-01 | 2006-01-26 | Herbert Bruder | Method for detecting and visualizing dynamic processes in an object volume |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104414675A (en) * | 2013-09-06 | 2015-03-18 | 西门子公司 | Method and x-ray system for dual-energy spectra ct scanning and image reconstruction |
| US9706971B2 (en) | 2013-09-06 | 2017-07-18 | Siemens Aktiengesellschaft | Method and X-ray system for dual-energy spectra CT scanning and image reconstruction |
Also Published As
| Publication number | Publication date |
|---|---|
| DE102010005635B4 (en) | 2018-09-20 |
| CN102151140B (en) | 2015-03-11 |
| DE102010005635A1 (en) | 2011-07-28 |
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