CN106408543A - Blocking optical grating optimization method and device for scattering correction of cone-beam CT (computed tomography) image - Google Patents
Blocking optical grating optimization method and device for scattering correction of cone-beam CT (computed tomography) image Download PDFInfo
- Publication number
- CN106408543A CN106408543A CN201610977011.4A CN201610977011A CN106408543A CN 106408543 A CN106408543 A CN 106408543A CN 201610977011 A CN201610977011 A CN 201610977011A CN 106408543 A CN106408543 A CN 106408543A
- Authority
- CN
- China
- Prior art keywords
- grating
- image
- stop
- coordinate
- longitudinal direction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T5/00—Image enhancement or restoration
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10072—Tomographic images
- G06T2207/10081—Computed x-ray tomography [CT]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/20—Special algorithmic details
- G06T2207/20004—Adaptive image processing
Abstract
The present invention provides a blocking optical grating optimization method and device for the scattering correction of a cone-beam CT (computed tomography) image. The method includes the following steps that: a blocking optical grating is scanned, and the swing model of the blocking optical grating is established; the initial coordinates of the blocking optical grating in the longitudinal direction of a detector in an initial projection are set, and an objective function between the data missing voxel value of the CBCT image and the coordinates of the blocking optical grating in the longitudinal direction of the detector is established; and the objective function is minimized by using a mesh adaptive direct search algorithm, so that the optimized coordinates of the blocking optical grating in the longitudinal direction of the detector can be generated. According to the brand new scattering correction method which does not require source compensation and is suitable for clinical CBCT in the present invention, mathematical optimization modeling is performed for data loss in an image field caused by the blocking optical grating; influence on a reconstructed image caused by the blocking device is quantitatively evaluated; the geometric optimal structure of the blocking device is solved by means of the mesh adaptive direct search method; and a solid theoretical basis is established for blocking device measurement-based scattering correction methods.
Description
Technical field
The present invention relates to the related medical imaging field of Cone-Beam CT application, more particularly, to one kind is for pyramidal CT image scattering
The stop grating optimization method and device revised.
Background technology
This part is it is intended that the embodiments of the present invention stated in claims provide background or context.Herein
Description is not because include just recognizing to be prior art in this part.
Image-guided radiation therapy technology (image guide radiation therapy, IGRT) is precisely to put at present
Main means in treatment.IGRT can provide accurate positional information to irradiate for accurate lesion localization and tumor, exists
Widely use in contemporary Minimally Invasive Surgery and radiotherapy.X-ray CBCT being arranged on treatment bedside is the weight of contemporary image guiding
Want realization rate.
However, along with the expansion of irradiated volume in single projection, CBCT (cone-beam computed
Tomography, CBCT) quality of image drastically deteriorates because the restriction of this basic physical process is polluted in scattering.Because traditional
CT reconstruction theory assume x-ray along straightline propagation, the transmitted intensity detecting is with path integral exponential damping.And scatter
Photon deviates incident beam direction it is impossible to be modeled in traditional CT reconstruction theory, thus the error becoming CT image reconstruction is come
Source.Research finds, scattered signal intensity is dull with the increase of x-ray irradiated volume to be strengthened.The scattering of CBCT is seriously polluted
Have impact on the accuracy of its CT value precision, the power of test of low contrast target and Rapid Dose Calculation, these shortcomings directly results in
CBCT cannot clinically extensively apply.The CBCT system not having Scattering correction is scanned to human body, scatter artefacts are led
Up to 350HU, therefore CBCT mainly or is used for Primary Location and pendulum position, in intervention and radiotherapy to the CT value error causing
Application is severely limited further.Scattering correction is to improve the primary problem solving of CBCT picture quality.
The method of the Scattering correction being currently known can be largely classified into two classes：Pretreatment and post-processing approach.Pretreatment side
Method correction scattering mainly passes through additional firmware device, stops scattered photon from reaching detector, such scattered signal and correlation
The statistical noise of connection is just suppressed in projection.The example of two typical preprocess methods includes, and increases detector and object
Between air-gap and use anti-scattering wiregrating.Widen with air-gap, the detectivity of the scattered photon spreading apart can reduce, and
Source signal is then unaffected.But the method is limited by CBCT equipment physical space itself, also need to increase x-ray dosage simultaneously and come
Make up the increase of distance, in clinical practice and impracticable.Anti-scattering wiregrating, using focusing on radiogenic lead grid grid, can hinder
The scattered light of gear non-focusing angle of incidence.The method there is also the not high defect of the extinction efficiency to scattered light.Commercial wiregrating at present
About 3 times of SPR reduction rate can only be provided it is impossible to ensure the CBCT picture quality under high scattering environments.Additionally, it also needs to increase
The radioactive dose of patient is compensating the source transmitted intensity being attenuated.
In view of the limitation of preprocess method, current research more concentrates in post processing.Post processing refers to by biography
System mode does Scattering correction after obtaining the projected image that scattering is polluted again.During due to theoretically random scatter can not possibly be predicted
Between, even if employing perfect post-processing approach, shot noise still can stay in the picture.Post-processing approach has many kinds, bag
Include：Analytic modeling method, Monte Carlo simulation approach, source modulation method and measurement method.Analytic modeling method thinks that scattered signal is source signal
Response after scattering nucleus, scattering nucleus are usually measured or simulation obtains.If scattering nucleus have linear translation space not
Become characteristic, then its calculating speed is quickly；But scattering estimated accuracy is limited accordingly and needs loaded down with trivial details adjustment to complex object
Parameter.Monte Carlo simulation approach passes through the interaction between simulated photons and illuminated object, is that scattered signal foundation is more smart
True statistical models, but the method amount of calculation is greatly, and quite time-consuming, current Computing ability limits it and is requiring
Application in the CBCT image reconstruction that near real-time is processed.Source modulation is addition high-frequency modulator, root between x-ray source and object
According to scattering the response characteristics different with source signal, frequency domain separates them.The method does not increase sufferer exposure dose
And sweep time, but its clinical application effect is limited by actual physics factor, such as spiral arm vibrations and large focal spot size etc..
Scattering correction based on measurement is the implementation method the most similar to the present invention.The method is in front of CBCT radiographic source
Add beam stop grating to be used for estimating scattered signal, such detector forms the shadow region only comprising scattered signal.Due to
Scatter distributions are mainly low-frequency component and are blocked grating disturbance very little, then entirely wild scatter distributions can be to detector shadow region
Scattering sampling interpolation draw.Accurate scattering can be obtained based on the method for measurement to estimate, but this is to be with source signal loss
Cost.Therefore, people typically require (once has stop grating, another stop light of moving away twice to each angle scanning
Grid), or mobile stop grating in scanning process.
The low cost of stopper and easy making property are so that be possibly realized based on the Scattering correction method of measurement.In China specially
It is proposed that a kind of cone beam CT scatter correction method based on complementary grating and its device in profit 201410380731.3.This invention,
Using a small amount of calculating of complementary grating scanner uni, realize the scatter correction of projected image, using the projected image after scatter correction
Scattering correction sectioning image just can be reconstructed.In Chinese patent 201010574162.8, a kind of scattering of CT system is proposed
Bearing calibration and CT system, by obtaining bright-field image, stopper are placed on detector and are swept between object, after scanning
To attenuation projection image, more respectively scanned object and scattering correction device are scanned obtaining projection image set and scatter correction
Image.Generate scattered signal distribution further according to bright-field image, scatter correction image and attenuation projection image, finally by projection
Image set obtains revised projection with the difference of scattered signal distribution.
Existing be scattered in modification method using stopper, be mostly required for twice sweep to compensate the original throwing of stop
Shadow signal, because which increasing the radioactive dose of patient it is impossible to be put to clinical practice.Additionally, these methods are used in desktop CBCT
Experiment porch, because experiment porch rotates the rotation of alternative source of light and detector using scanning object, CT system etc. center very
Stable, stopper not in the same time location of projection be almost consistent, be so scattered the difficulty revised using stopper
Will substantially reduce, these methods are only applicable to wait the laboratory desktop CBCT system of central stabilizer.However, clinical CBCT system
Due to centre deviations such as the vibrations in frame rotary course and rotations, lead to stop that optical grating projection position rotates with frame and becomes
Change, cause the scattered signal of grating region to be difficult to accurately extract.
Content of the invention
It is an object of the invention to provide a kind of stop grating optimization method and device for pyramidal CT image Scattering correction,
With solve the problems, such as existing be scattered revising using stopper when increase scanning times and scattered signal and be difficult to accurately extract.
In order to achieve the above object, the embodiment of the present invention provides a kind of stop grating for pyramidal CT image Scattering correction
Optimization method, including：Scanning stops grating, sets up the described swinging model stopping grating；Set and stop described in initial projections
Initial coordinate in detector longitudinal direction for the grating, and according to described swinging model, set up CBCT image data missinges voxel value with
Stop object function between the coordinate in detector longitudinal direction for the grating；Minimize institute using mesh adaption Direct search algorithm
State object function, generate described stop optimization coordinate in detector longitudinal direction for the grating.
Further, in one embodiment, described scanning stops grating, sets up the described swinging model stopping grating, tool
Body includes：In the described projection stopping grating, determine a described suitable threshold stopping grating using maximum variance between clusters
Value, carries out the image segmentation based on threshold value to it, generates bianry image, determines described stop grating by the bianry image generating
Coordinate position, obtain described stop grating swinging model.
Further, in one embodiment, stop grating in detector longitudinal direction described in described setting initial projections
Initial coordinate, including：Set described stop grating piece number be n, in initial projections i-th stop grating in detector longitudinal direction
Coordinate be：G=(g1,g2,…,gn)T.
Further, in one embodiment, described according to described swinging model, set up CBCT image data missinges voxel value
And stop object function between the coordinate in detector longitudinal direction for the grating, specifically include：According to described swinging model and just
Beginning coordinate, the described projected image stopping that grating projects in every width of simulation；Backprojection reconstruction is carried out to described every width projected image；
According to the image after backprojection reconstruction, set up left and right half and fan the voxel value of shortage of data and described stop light after reconstruction image merges
Object function between the coordinate in detector longitudinal direction for the grid.
Further, in one embodiment, described utilization mesh adaption Direct search algorithm minimizes described target letter
Number, generates described stop optimization coordinate in detector longitudinal direction for the grating, including：Made with the parameter of the initial stop grating setting
For the initial value of mesh adaption Direct search algorithm, generate described stop optimization coordinate in detector longitudinal direction for the grating.
Further, in one embodiment, the described initial stop grating setting is as being uniformly distributed at equal intervals.
Further, in one embodiment, described stop grating is to refer to chiasma type grating.
In order to achieve the above object, the embodiment of the present invention also provides a kind of stop light for pyramidal CT image Scattering correction
Grid optimize device, including：Swinging model sets up module, stops grating for scanning, sets up the described swinging model stopping grating；
Object function sets up module, for setting stop initial coordinate in detector longitudinal direction for the grating described in initial projections, and root
According to described swinging model, set up CBCT image data missinges voxel value and stop grating between the coordinate in detector longitudinal direction
Object function；Minimize module, for minimizing described object function using mesh adaption Direct search algorithm, generate described
Stop optimization coordinate in detector longitudinal direction for the grating.
Further, in one embodiment, described swinging model set up module for scanning stop grating, set up described resistance
Be in the light the swinging model of grid, specifically includes：In the described projection stopping grating, determine described resistance using maximum variance between clusters
Be in the light an appropriate threshold of grid, and it is carried out with the image segmentation based on threshold value, generates bianry image, by the binary map generating
As determining the described coordinate position stopping grating, obtain the described swinging model stopping grating.
Further, in one embodiment, described object function is set up module and is specifically included：Initial coordinate setup unit,
For setting the described piece number stopping grating as n, the in initial projectionsiPiece stops that coordinate in detector longitudinal direction for the grating is：G
=(g1,g2,…,gn)T；Projected image analogue unit, for according to described swinging model and initial coordinate, simulating described resistance
The projected image that the grid that are in the light project in every width；Back projection unit, for carrying out backprojection reconstruction to described every width projected image；Letter
Number sets up unit, for according to the image after backprojection reconstruction, setting up the body that shortage of data after reconstruction image merges is fanned in left and right half
Element value and described stop object function between the coordinate in detector longitudinal direction for the grating.
The stop grating optimization method and device for pyramidal CT image Scattering correction of the embodiment of the present invention is it is proposed that one
Kind brand-new compensate without source and be suitable for the Scattering correction method of clinical CBCT.The present invention sets up by image partition method
Stop the swing mathematical model that optical grating projection is caused with frame vibrations because of off-centrings such as cantilevers, successfully stop grating is applied to
Clinical cone beam computed tomography (CT) scattering correction；The shortage of data that stop grating is caused in image area carries out mathematical optimization modeling, qualitative assessment
The impact to reconstruction image for the stopper, solves the geometry optimum structure of stopper, is base by mesh adaption direct search method
Scattering correction method in stopper measurement establishes solid theoretical basiss, discloses stopper further and designs to clinical cone-beam
The importance of CT Scattering correction.
Brief description
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
Have technology description in required use accompanying drawing be briefly described it should be apparent that, drawings in the following description be only this
Some embodiments of invention, for those skilled in the art, without having to pay creative labor, can also root
Obtain other accompanying drawings according to these accompanying drawings.
Fig. 1 is the handling process of the stop grating optimization method for pyramidal CT image Scattering correction of the embodiment of the present invention
Figure；
Fig. 2 is that the principle of the stop grating optimization method for pyramidal CT image Scattering correction of the embodiment of the present invention is illustrated
Figure；
Fig. 3 is the geometric model of the stop grating after the optimization obtaining in embodiment illustrated in fig. 2；
Fig. 4 is the structural representation stopping grating optimization device for pyramidal CT image Scattering correction of the embodiment of the present invention
Figure；
Fig. 5 sets up the structural representation of module 102 for the object function in embodiment illustrated in fig. 4；
Fig. 6 is the actual correction Contrast on effect schematic diagram obtaining according to the stop grating optimization method of the present invention.
Specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation description is it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of not making creative work
Embodiment, broadly falls into the scope of protection of the invention.
Art technology technical staff is known, embodiments of the present invention can be implemented as a kind of system, device, equipment,
Method or computer program.Therefore, the disclosure can be implemented as following form, that is,：Completely hardware, completely soft
Part (includes firmware, resident software, microcode etc.), or the form that hardware and software combines.
Below with reference to some representative embodiments of the present invention, the in detail principle of the explaination present invention and spirit.
The embodiment of the present invention proposes " referring to intersect " type and stops the mathematical model to reconstructed image quality for the grating, this mathematical model
Grating shake is taken into account, the method introducing mesh adaption direct search solves object function, obtains being suitable for clinic
The stop grating geometry designs of CBCT Scattering correction.Then the stop grating of design is placed on before radiographic source, accurately extracts and dissipate
After penetrating sample by interpolation method estimate each projection scatter distributions, finally by half fan sweeping retouch algorithm for reconstructing accurate reconstruction go out scattered
Penetrate revised image, single sweep operation realizes clinical CBCT Scattering correction.
Fig. 1 is the handling process of the stop grating optimization method for pyramidal CT image Scattering correction of the embodiment of the present invention
Figure.As shown in figure 1, including：
Step S101, scanning stops grating, sets up the described swinging model stopping grating；
Step S102, sets and stops initial coordinate in detector longitudinal direction for the grating described in initial projections, and according to institute
State swinging model, set up CBCT image data missinges voxel value and stop target between the coordinate in detector longitudinal direction for the grating
Function；
Step S103, minimizes described object function using mesh adaption Direct search algorithm, generates described stop light
Optimization coordinate in detector longitudinal direction for the grid.
When being embodied as, with reference to Fig. 2, it is that the stop grating for pyramidal CT image Scattering correction of the embodiment of the present invention is excellent
The principle schematic of change method.100 (the setting up grating swinging model) of the corresponding Fig. 2 of step S101 of Fig. 1, step S102 of Fig. 1
200 (the stopping grating mathematical modeling) of corresponding Fig. 2,300 (solutions of model) of corresponding Fig. 2 of step S103 of Fig. 1.In Fig. 2 institute
Show in embodiment, carry out principle explanation using as a example 10 gratings.
In step S101 of the present embodiment, referring to Fig. 2 100 it is necessary first to using Experience Design one stop grating,
Then it is scanned, is projected in what this clinical CBCT caused because the off-centrings such as cantilever and frame shake for studying leads
Swinging model.In a preferred embodiment, designed stop grating is " referring to intersect " grating.
In the projection of the stop grating that scanning obtains, determine described stop grating one using maximum variance between clusters
Appropriate threshold, carries out the image segmentation based on threshold value to it, area-of-interest is converted into a secondary bianry image, can be stopped
Raster center point coordinate figure in this direction, obtains frame angle and the relation stopping stop position change, i.e. by generating
Bianry image determine the described coordinate position stopping grating, the coordinate position according to grating can obtain described stopping grating
Swinging model.
In step S102 of the present embodiment, referring to the 200 of Fig. 2, stop grating and image data missinges voxel to be set up
The object function of quantity.Its principle is：When stopping that grating spacings are wider, schemed by the CBCT that two and Ban fan scanning algorithms reconstruct
As the voxel of shortage of data is fewer.While ensureing that accuracy is estimated in scattering, stop that the design of grating needs to ensure picture number
According to the minimum of disappearance number of voxel, an object function with regard to stopping grating placement location therefore can be designed.
First have to set and described in initial projections, stop initial coordinate in detector longitudinal direction for the grating.Set described stop
The piece number of grating is n, the in initial projectionsiPiece stops that coordinate in detector longitudinal direction for the grating is：
G=(g1,g2,…,gn)T(1)
Then according to described swinging model and initial coordinate, the described projection stopping that grating projects in every width of simulation
Picture.When being embodied as, simulation stops the projected image of grating, makes barrier zones be 1, and the region not being blocked is 0.Due to swinging
The reason with centre deviations such as frames, stop coordinate position that grating projects in every width and differ, djFor stopping grating in jth
Width project migration amount.
P in formula (2) and formula (3)i,j(u, v) is respectively the image in the projection of jth width that left and right side monolithic stops grating,
U is detector pixels across width, w0For stopping raster width, u, v are respectively the horizontal stroke of detector, ordinate value.
Formula (2) is added with formula (3), obtains：
PjFor stopping the image in the projection of jth width of grating.
To m width projection Pj(- u v) carries out backprojection reconstruction, obtains to be multiplied by weighting function f (u, v) and f respectively：
It is noted that MlAnd MrIn by stopping that the voxel value that affected of grating is non-zero, and be not affected by stopping grating impact
Voxel value be zero, Ml·MrRegion for non-zero is the voxel that shortage of data after reconstruction image merges is fanned in left and right half, stops light
The optimization design of grid requires to rebuild the minimum of the voxel value sum (needing binaryzation) of shortage of data in volume.Object function is built
Vertical process is as shown in Fig. 2 following object functions can be obtained：
Wherein,For constraints, represent that left and right grating must be interspersed, and
The vertical coordinate of grating can not exceed the scope of detector vertical coordinate.
In step S103 of the present embodiment, referring to the 300 of Fig. 2, stop the parameter of grating as net with initially set
The initial value of lattice self adaptation Direct search algorithm, generates described stop optimization coordinate in detector longitudinal direction for the grating.Wherein, institute
The parameter stating the stop grating initially setting is as being uniformly distributed at equal intervals naturally it is also possible to adopt other spaced apart.
The method introducing mesh adaption direct search, solves object function.Herein in carried Optimized model, shake and machine
Side-play amount d stopping grating vibrations causing of the centre deviations such as framejFor target following gained.Currently for optimization problem
Method for solving has mathematical programming approach, heuritic approach and direct search method etc..Stop grating Optimized model have very strong non-
Linearly, and do not have derivative information can provide, therefore can not be solved using mathematical programming approach；And as heuritic approach such as mould
Although plan annealing algorithm and genetic algorithm etc. is even better in ability of searching optimum, the search capability in local but exists
Deficiency, the speed of convergence is also very slow.Due to object function of every generation, need to carry out back projection's operation, if the present invention
Object function use heuritic approach it may appear that substantial amounts of redundancy iteration, time-consuming.Mesh adaption directly searches (mesh-
Adaptive direct search, MADS) decision vector of algorithm can be discrete, continuous and binary system etc., target
Function and its constraints can be " black box functions ", and MADS algorithm is suitable for solving multivariable mathematical model, therefore this
Bright using MADS algorithm to stop grating Optimized model solve.During solution, in a preferred embodiment, with being uniformly distributed resistance
Be in the light grid parameter as the initial value of MADS object function, solve the grating geometric model that draws as shown in Figure 3.
After the stop optical grating construction optimizing is obtained by above step, place it in radiographic source and scanned object it
Between, after collection project objects, using determining behind the position that grating is located based on the image partition method of threshold value, using gathered
Scattered signal, Interpolate estimation goes out scatter distributions, after original image deducts scatter distributions, obtains the projected image after Scattering correction.
Then recycle and algorithm for reconstructing is retouched based on half fan sweeping of Parker function, reconstruct the image after Scattering correction.
Although it should be noted that describe the operation of the inventive method in the accompanying drawings with particular order, this does not require that
Or hint must execute these operations according to this particular order, or having to carry out all shown operation just enables the phase
The result hoped.Additionally or alternatively, it is convenient to omit some steps, multiple steps are merged into a step execution, and/or will
One step is decomposed into execution of multiple steps.
After the method describing exemplary embodiment of the invention, next, with reference to Fig. 4 to the present invention exemplary reality
The stop grating optimization device for pyramidal CT image Scattering correction applying mode is introduced.The enforcement of this device may refer to
The enforcement of said method, repeats no more in place of repetition.Term " module " used below and " unit ", can be to realize making a reservation for
The software of function and/or hardware.Although the module described by following examples preferably to be realized with software, hardware, or
The realization of the combination of person's software and hardware is also may and to be contemplated.
Fig. 4 is the structural representation stopping grating optimization device for pyramidal CT image Scattering correction of the embodiment of the present invention
Figure.As shown in figure 4, including：
Swinging model sets up module 101, stops grating for scanning, sets up the described swinging model stopping grating；Target
Function sets up module 102, for setting stop initial coordinate in detector longitudinal direction for the grating described in initial projections, and according to
Described swinging model, sets up CBCT image data missinges voxel value and stops mesh between the coordinate in detector longitudinal direction for the grating
Scalar functions；Minimize module 103, for minimizing described object function using mesh adaption Direct search algorithm, generate institute
State stop optimization coordinate in detector longitudinal direction for the grating.
Further, in the present embodiment, described swinging model set up module 101 for scanning stop grating, set up institute
State the swinging model stopping grating, specifically include：In the described projection stopping grating, determine institute using maximum variance between clusters
State an appropriate threshold stopping grating, it is carried out with the image segmentation based on threshold value, generate bianry image, by the two of generation
Value image determines the described coordinate position stopping grating, obtains the described swinging model stopping grating.
Further, in the present embodiment, as shown in figure 5, described object function sets up module 102 specifically includes：
Initial coordinate setup unit 1021, for setting the described piece number stopping grating as n, the in initial projectionsiPiece hinders
The coordinate in detector longitudinal direction for the grid that is in the light is：G=(g1,g2,…,gn)T；
Projected image analogue unit 1022, for according to described swinging model and initial coordinate, simulating described stop light
The projected image that grid project in every width；
Back projection unit 1023, for carrying out backprojection reconstruction to described every width projected image；
Function sets up unit 1024, fans reconstruction image fusion for according to the image after backprojection reconstruction, setting up left and right half
The voxel value of the shortage of data and described stop grating object function between the coordinate in detector longitudinal direction afterwards.
Although additionally, referring to that in above-detailed the stop grating for pyramidal CT image Scattering correction optimizes device
Some units, but this divide only not enforceable.In fact, according to the embodiment of the present invention, it is described above
The feature of two or more units and function can embody in a unit.Equally, an above-described unit
Feature and function can also Further Division be to be embodied by multiple units.
By embodiments of the present invention be designed optimize stop grating through experiment, simulation and using it was demonstrated that
Truly feasible.On the CBCT of Varian Trilogy, tested using Catphan504 die body, designed using the present invention excellent
The stop grating changed is scattered revising, and the CT error of area-of-interest drops to 11HU by 115HU, and contrast improves 1.45
Times, as shown in fig. 6, (a) is classified as the image before correction, (b) is classified as revised image to correction effect.
The stop grating optimization method and device for pyramidal CT image Scattering correction of the embodiment of the present invention is it is proposed that one
Kind brand-new compensate without source and be suitable for the Scattering correction method of clinical CBCT.The present invention sets up by image partition method
Stop the swing mathematical model that optical grating projection is caused with frame vibrations because of off-centrings such as cantilevers, successfully stop grating is applied to
Clinical cone beam computed tomography (CT) scattering correction；The shortage of data that stop grating is caused in image area carries out mathematical optimization modeling, qualitative assessment
The impact to reconstruction image for the stopper, solves the geometry optimum structure of stopper, is base by mesh adaption direct search method
Scattering correction method in stopper measurement establishes solid theoretical basiss, discloses stopper further and designs to clinical cone-beam
The importance of CT Scattering correction.
Those skilled in the art are it should be appreciated that embodiments of the invention can be provided as method, system or computer program
Product.Therefore, the present invention can be using complete hardware embodiment, complete software embodiment or the reality combining software and hardware aspect
Apply the form of example.And, the present invention can be using in one or more computers wherein including computer usable program code
The upper computer program implemented of usable storage medium (including but not limited to disk memory, CD-ROM, optical memory etc.) produces
The form of product.
The present invention is the flow process with reference to method according to embodiments of the present invention, equipment (system) and computer program
Figure and/or block diagram are describing.It should be understood that can be by each stream in computer program instructions flowchart and/or block diagram
Flow process in journey and/or square frame and flow chart and/or block diagram and/or the combination of square frame.These computer programs can be provided
The processor instructing general purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device is to produce
A raw machine is so that produced for reality by the instruction of computer or the computing device of other programmable data processing device
The device of the function of specifying in present one flow process of flow chart or multiple flow process and/or one square frame of block diagram or multiple square frame.
These computer program instructions may be alternatively stored in and can guide computer or other programmable data processing device with spy
Determine in the computer-readable memory that mode works so that the instruction generation inclusion being stored in this computer-readable memory refers to
Make the manufacture of device, this command device realize in one flow process of flow chart or multiple flow process and/or one square frame of block diagram or
The function of specifying in multiple square frames.
These computer program instructions also can be loaded in computer or other programmable data processing device so that counting
On calculation machine or other programmable devices, execution series of operation steps to be to produce computer implemented process, thus in computer or
On other programmable devices, the instruction of execution is provided for realizing in one flow process of flow chart or multiple flow process and/or block diagram one
The step of the function of specifying in individual square frame or multiple square frame.
Apply specific embodiment in the present invention principle of the present invention and embodiment are set forth, above example
Explanation be only intended to help and understand the method for the present invention and its core concept；Simultaneously for one of ordinary skill in the art,
According to the thought of the present invention, all will change in specific embodiments and applications, in sum, in this specification
Hold and should not be construed as limitation of the present invention.
Claims (10)
1. a kind of stop grating optimization method for pyramidal CT image Scattering correction is it is characterised in that include：
Scanning stops grating, sets up the described swinging model stopping grating；
Set and stop initial coordinate in detector longitudinal direction for the grating described in initial projections, and according to described swinging model, build
Vertical CBCT image data missinges voxel value and stop object function between the coordinate in detector longitudinal direction for the grating；
Minimize described object function using mesh adaption Direct search algorithm, generate described stop grating in detector longitudinally
On optimization coordinate.
2. the stop grating optimization method for pyramidal CT image Scattering correction according to claim 1 it is characterised in that
Described scanning stops grating, sets up the described swinging model stopping grating, specifically includes：
In the described projection stopping grating, determine a described appropriate threshold stopping grating using maximum variance between clusters,
It is carried out with the image segmentation based on threshold value, generates bianry image, described stop grating is determined by the bianry image generating
Coordinate position, obtains the described swinging model stopping grating.
3. the stop grating optimization method for pyramidal CT image Scattering correction according to claim 1 it is characterised in that
Initial coordinate in detector longitudinal direction for the grating is stopped described in described setting initial projections, including：
Set the described piece number stopping grating as n, the in initial projectionsiPiece stops that coordinate in detector longitudinal direction for the grating is：G
=(g1,g2,···,gn)T.
4. the stop grating optimization method for pyramidal CT image Scattering correction according to claim 1 it is characterised in that
Described according to described swinging model, set up CBCT image data missinges voxel value with stop coordinate in detector longitudinal direction for the grating
Between object function, specifically include：
According to described swinging model and initial coordinate, simulate the described projected image stopping that grating projects in every width；
Backprojection reconstruction is carried out to described every width projected image；
According to the image after backprojection reconstruction, set up left and right half and fan the voxel value of shortage of data and described resistance after reconstruction image merges
Be in the light object function between the coordinate in detector longitudinal direction for the grid.
5. the stop grating optimization method for pyramidal CT image Scattering correction according to claim 1 it is characterised in that
Described utilization mesh adaption Direct search algorithm minimizes described object function, generates described stop grating in detector longitudinally
On optimization coordinate, including：
With the initial initial value as mesh adaption Direct search algorithm for the parameter stopping grating setting, generate described stop
Optimization coordinate in detector longitudinal direction for the grating.
6. the stop grating optimization method for pyramidal CT image Scattering correction according to claim 5 it is characterised in that
The described initial stop grating setting is as being uniformly distributed at equal intervals.
7. the stop grating optimization method for pyramidal CT image Scattering correction according to any one of claim 1～6, its
It is characterised by, described stop grating is to refer to chiasma type grating.
8. a kind of stop grating for pyramidal CT image Scattering correction optimizes device it is characterised in that including：
Swinging model sets up module, stops grating for scanning, sets up the described swinging model stopping grating；
Object function sets up module, for setting stop initial coordinate in detector longitudinal direction for the grating described in initial projections,
And according to described swinging model, set up CBCT image data missinges voxel value with stop coordinate in detector longitudinal direction for the grating it
Between object function；
Minimize module, for minimizing described object function using mesh adaption Direct search algorithm, generate described stop
Optimization coordinate in detector longitudinal direction for the grating.
9. stop grating for pyramidal CT image Scattering correction according to claim 8 optimize device it is characterised in that
Described swinging model set up module for scanning stop grating, set up described stop grating swinging model, specifically include：
In the described projection stopping grating, determine a described appropriate threshold stopping grating using maximum variance between clusters,
It is carried out with the image segmentation based on threshold value, generates bianry image, described stop grating is determined by the bianry image generating
Coordinate position, obtains the described swinging model stopping grating.
10. the stop grating for pyramidal CT image Scattering correction according to claim 8 optimizes device, and its feature exists
In described object function is set up module and specifically included：
Initial coordinate setup unit, for setting the described piece number stopping grating as n, the in initial projectionsiPiece stops that grating exists
Coordinate in detector longitudinal direction is：G=(g1,g2,···,gn)T；
Projected image analogue unit, for according to described swinging model and initial coordinate, simulating described stop grating in every width
The projected image of projection；
Back projection unit, for carrying out backprojection reconstruction to described every width projected image；
Function sets up unit, lacks for according to the image after backprojection reconstruction, setting up data after left and right half fan reconstruction image merges
Object function between the coordinate in detector longitudinal direction for the voxel value and described stop grating losing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610977011.4A CN106408543B (en) | 2016-11-07 | 2016-11-07 | A kind of blocking grating optimization method and device for pyramidal CT image Scattering correction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610977011.4A CN106408543B (en) | 2016-11-07 | 2016-11-07 | A kind of blocking grating optimization method and device for pyramidal CT image Scattering correction |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106408543A true CN106408543A (en) | 2017-02-15 |
| CN106408543B CN106408543B (en) | 2019-04-23 |
Family
ID=58015327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610977011.4A Active CN106408543B (en) | 2016-11-07 | 2016-11-07 | A kind of blocking grating optimization method and device for pyramidal CT image Scattering correction |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106408543B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018082088A1 (en) * | 2016-11-07 | 2018-05-11 | 深圳先进技术研究院 | Blocking optical grating optimization method and device for scattering correction of cone-beam ct image |
| CN109259781A (en) * | 2018-07-26 | 2019-01-25 | 深圳先进技术研究院 | A kind of grating stopper and method, CBCT system for adjusting grating space |
| CN111588997A (en) * | 2020-05-18 | 2020-08-28 | 上海联影医疗科技有限公司 | Method, device and equipment for determining scattering quantity and storage medium |
| CN112150542A (en) * | 2020-09-24 | 2020-12-29 | 上海联影医疗科技股份有限公司 | Method and device for measuring radiation field, electronic equipment and storage medium |
| CN116531015A (en) * | 2023-07-04 | 2023-08-04 | 中国科学院深圳先进技术研究院 | Image reconstruction method, device, electronic equipment and storage medium |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090225932A1 (en) * | 2008-02-27 | 2009-09-10 | Lei Zhu | Cone-beam CT imaging scheme |
| CN104161536A (en) * | 2014-07-30 | 2014-11-26 | 西北工业大学 | Cone beam CT scatter correction method and device based on complementary gratings |
| CN104408753A (en) * | 2014-10-27 | 2015-03-11 | 浙江大学 | Self-adaptive iteration scattering correction method of cone beam CT |
| CN105011955A (en) * | 2014-04-30 | 2015-11-04 | 株式会社东芝 | X-ray diagnostic apparatus and image processing apparatus |
| CN105631909A (en) * | 2015-12-23 | 2016-06-01 | 浙江大学 | CBCT iterative reconstruction method with artifact correction assistance |
-
2016
- 2016-11-07 CN CN201610977011.4A patent/CN106408543B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090225932A1 (en) * | 2008-02-27 | 2009-09-10 | Lei Zhu | Cone-beam CT imaging scheme |
| CN105011955A (en) * | 2014-04-30 | 2015-11-04 | 株式会社东芝 | X-ray diagnostic apparatus and image processing apparatus |
| CN104161536A (en) * | 2014-07-30 | 2014-11-26 | 西北工业大学 | Cone beam CT scatter correction method and device based on complementary gratings |
| CN104408753A (en) * | 2014-10-27 | 2015-03-11 | 浙江大学 | Self-adaptive iteration scattering correction method of cone beam CT |
| CN105631909A (en) * | 2015-12-23 | 2016-06-01 | 浙江大学 | CBCT iterative reconstruction method with artifact correction assistance |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018082088A1 (en) * | 2016-11-07 | 2018-05-11 | 深圳先进技术研究院 | Blocking optical grating optimization method and device for scattering correction of cone-beam ct image |
| US10722205B2 (en) | 2016-11-07 | 2020-07-28 | Shenzhen Institutes Of Advanced Technology | Method and apparatus for optimizing blocking grating for cone beam CT image scattering correction |
| CN109259781A (en) * | 2018-07-26 | 2019-01-25 | 深圳先进技术研究院 | A kind of grating stopper and method, CBCT system for adjusting grating space |
| CN111588997A (en) * | 2020-05-18 | 2020-08-28 | 上海联影医疗科技有限公司 | Method, device and equipment for determining scattering quantity and storage medium |
| CN111588997B (en) * | 2020-05-18 | 2022-07-12 | 上海联影医疗科技股份有限公司 | Method, device and equipment for determining scattering quantity and storage medium |
| CN112150542A (en) * | 2020-09-24 | 2020-12-29 | 上海联影医疗科技股份有限公司 | Method and device for measuring radiation field, electronic equipment and storage medium |
| CN112150542B (en) * | 2020-09-24 | 2023-02-24 | 上海联影医疗科技股份有限公司 | Method and device for measuring radiation field, electronic equipment and storage medium |
| CN116531015A (en) * | 2023-07-04 | 2023-08-04 | 中国科学院深圳先进技术研究院 | Image reconstruction method, device, electronic equipment and storage medium |
| CN116531015B (en) * | 2023-07-04 | 2023-10-03 | 中国科学院深圳先进技术研究院 | Image reconstruction method, device, electronic equipment and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106408543B (en) | 2019-04-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3400876B1 (en) | Automatic estimating and reducing scattering in computed tomography scans | |
| CN106408543B (en) | A kind of blocking grating optimization method and device for pyramidal CT image Scattering correction | |
| CN109621228B (en) | Radiation dose calculation device, radiation dose calculation apparatus, and storage medium | |
| RU2449372C2 (en) | Efficient user interaction with polygonal meshes for medical image segmentation | |
| CN101688917A (en) | Method for eliminating scatter artefacts in computed tomography | |
| Da Silva et al. | Sub-second pencil beam dose calculation on GPU for adaptive proton therapy | |
| CN110678906B (en) | Generation of accurate hybrid data sets for quantitative molecular imaging | |
| US9295432B2 (en) | Method of determining distribution of a dose in a body | |
| Penfold | Image reconstruction and Monte Carlo simulations in the development of proton computed tomography for applications in proton radiation therapy | |
| JP2020179146A (en) | Medical image processing apparatus, x-ray computed tomography apparatus, and program | |
| CN111001097B (en) | Radiotherapy dose evaluation system, device and storage medium | |
| EP4341905A1 (en) | Iterative image reconstruction | |
| CN111462267A (en) | Method and system for acquiring X-ray projection data | |
| WO2018082088A1 (en) | Blocking optical grating optimization method and device for scattering correction of cone-beam ct image | |
| Ordoñez et al. | Fast in situ image reconstruction for proton radiography | |
| US11424037B2 (en) | Disease simulation in medical images | |
| Zhu et al. | Total variation superiorization in dual-energy CT reconstruction for proton therapy treatment planning | |
| US9406128B2 (en) | X-ray dose distribution calculation for a computed tomography examination | |
| Bartolac | Fluence field modulated computed tomography | |
| Alsaffar et al. | Computational scatter correction in near real-time with a fast Monte Carlo photon transport model for high-resolution flat-panel CT | |
| US20230082049A1 (en) | Structure contouring, such as for segmentation or radiation treatment planning, using a 3d paint brush combined with an edge-detection algorithm | |
| US20230372739A1 (en) | Techniques for detecting movement during radiotherapy treatment | |
| US20240131360A1 (en) | Updating proton stopping power maps for proton radiation therapy treatment planning | |
| Pluta et al. | A New Statistical Approach to Image Reconstruction with Rebinning for the X-Ray CT Scanners with Flying Focal Spot Tube | |
| Niu et al. | UBES: Unified scatter correction using ultrafast Boltzmann equation solver for conebeam CT |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |