CN106709913B - Cone-Beam CT incident intensity calculation method and device - Google Patents
Cone-Beam CT incident intensity calculation method and device Download PDFInfo
- Publication number
- CN106709913B CN106709913B CN201611262008.0A CN201611262008A CN106709913B CN 106709913 B CN106709913 B CN 106709913B CN 201611262008 A CN201611262008 A CN 201611262008A CN 106709913 B CN106709913 B CN 106709913B
- Authority
- CN
- China
- Prior art keywords
- projected image
- incident intensity
- gray value
- ratio
- intensity
- 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.)
- Active
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0012—Biomedical image inspection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/161—Applications in the field of nuclear medicine, e.g. in vivo counting
-
- 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]
Abstract
The present invention provides a kind of Cone-Beam CT incident intensity calculation method and devices.Method includes the following steps: a. obtains total incident intensity of multiple projected image according to the accumulated dose and incident intensity of multiple projected images and the correction coefficient of dosage；B. the representative gray value of each projected image is calculated；C. according to the representative gray value of each projected image, the ratio in multiple projected image between the incident intensity of every two projected image is calculated；And d. calculates the mean incident intensity of each projected image according to the ratio between total incident intensity and the incident intensity of every two projected image.
Description
Technical field
The invention mainly relates to field of radiation therapy more particularly to a kind of Cone-Beam CT incident intensity calculation method and devices.
Background technique
Radiotherapy (abbreviation radiotherapy) is a kind of local therapeutic approaches using radiation cure tumour.Radioactive ray include putting
The X-ray for α, β, gamma-rays and all kinds of roentgenotherapia machines or the accelerator generation that injectivity isotope generates, electric wire, proton beam
And other particles beams etc..
For guarantee radiotherapy accuracy, the treatment for the first time of accurate radiotherapy must carry out Cone-Beam CT (Cone Beam CT,
CBCT it) scans.The X-ray incident intensity I of CBCT0Calculation method there are two types of.The first is utilized in kV-CBCT system
Incident intensity I0With voltage value (kV), current value (mA), existing one-to-one relationship between the duration (ms).School can be passed through
Just establishing the look-up table of these corresponding relationships.In image reconstruction, by searching for voltage value, current value, duration, phase is found
Corresponding incident intensity.The accuracy of bulb and high pressure generator is within 1%.Second is in MV-CBCT system
In, incident intensity I is established using absolute dosages instrument in image rectification0With the corresponding relationship of dose value MU.Lead to when image reconstruction
The dose value MU of overwriting is calculated corresponding incident intensity I0.First method can not be suitable for MV-CBCT system.This
It is because being influenced by linear accelerator, magnetron etc., incident electron intensity and voltage, current value do not have one-to-one relationship,
It can not realize that incident intensity I0 is calculated by way of establishing look-up table.The uncertainty of the dosage record value of second method compared with
Greatly.
It is therefore desirable for there is one kind that can be suitable for kV-CBCT system and MV-CBCT system simultaneously, and incident intensity calculates
The high method of accuracy.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of Cone-Beam CT incident intensity calculation method and devices, can be improved
The accuracy that single projected image incident intensity calculates.
In order to solve the above technical problems, the present invention provides a kind of Cone-Beam CT incident intensity calculation method, including following step
Rapid: a. obtains multiple projected image according to the accumulated dose and incident intensity of multiple projected images and the correction coefficient of dosage
Total incident intensity；B. the representative gray value of each projected image is calculated；C. according to the representative gray scale of each projected image
Value, calculates the ratio in multiple projected image between the incident intensity of every two projected image；And d. is according to total incidence
Ratio between intensity and the incident intensity of every two projected image calculates the mean incident intensity of each projected image.
In one embodiment of this invention, after step d further include: e. is strong using the average incident of each projected image
Degree carries out three-dimensional image reconstruction, obtains the attenuation coefficient of each voxel；F. each throwing is updated according to the attenuation coefficient of each voxel
The mean incident intensity of shadow image；G. iteration carries out step e and f, until the mean incident intensity of each projected image meets convergence
Condition.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative throwing
The logarithm of the gray value of each pixel of shadow image.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative throwing
The logarithm of the gray value of each pixel on the transverse center hatching line of shadow image.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative packet
The logarithm of the gray value of each pixel of at least one regional area of the transverse center hatching line containing projected image.
In one embodiment of this invention, according to the representative gray value of each projected image, multiple perspective view is calculated
The method of ratio as between the incident intensity of every two projected image are as follows:
Wherein Ik1Represent the incident intensity of the first projected image, Ik2Represent the incident intensity of the second projected image, Ck1It represents
The representative gray value of first projected image, Ck2The representative gray value of the second projected image is represented, n represents total voxel number.
In one embodiment of this invention, according between total incident intensity and the incident intensity of every two projected image
Ratio, the step of calculating the mean incident intensity of each projected image include: according to the incident intensity of every two projected image it
Between ratio, calculate ratio of each projected image in total incident intensity；According to each projected image in total incident intensity
Ratio and total incident intensity calculate the mean incident intensity of each projected image.
The present invention separately proposes a kind of Cone-Beam CT incident intensity computing device, including memory and processor.The memory is deposited
Store up computer-readable instruction.The processor executes the computer-readable instruction to implement following step: a. is according to multiple perspective views
The accumulated dose and incident intensity of picture and the correction coefficient of dosage obtain total incident intensity of multiple projected image；B. it calculates
The representative gray value of each projected image；C. according to the representative gray value of each projected image, multiple perspective view is calculated
Ratio as between the incident intensity of every two projected image；And d. is according to total incident intensity and every two projected image
Incident intensity between ratio, calculate the mean incident intensity of each projected image.
In one embodiment of this invention, processor executes the computer-readable instruction also to implement following step: e. makes
Three-dimensional image reconstruction is carried out with the mean incident intensity of each projected image, obtains the attenuation coefficient of each voxel；F. according to every
The attenuation coefficient of a voxel updates the mean incident intensity of each projected image；And g. iteration carries out step e and f, until each
The mean incident intensity of projected image meets the condition of convergence.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative throwing
The logarithm of the gray value of each pixel of shadow image.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative throwing
The logarithm of the gray value of each pixel on the transverse center hatching line of shadow image.
In one embodiment of this invention, the step of calculating the representative gray value of each projected image includes: cumulative packet
The logarithm of the gray value of each pixel of at least one regional area of the transverse center hatching line containing projected image.
In one embodiment of this invention, according to the representative gray value of each projected image, multiple perspective view is calculated
The method of ratio as between the incident intensity of every two projected image are as follows:
Wherein Ik1Represent the incident intensity of the first projected image, Ik2Represent the incident intensity of the second projected image, Ck1It represents
The representative gray value of first projected image, Ck2The representative gray value of the second projected image is represented, n represents total voxel number.
In one embodiment of this invention, according between total incident intensity and the incident intensity of every two projected image
Ratio, the step of calculating the mean incident intensity of each projected image include: according to the incident intensity of every two projected image it
Between ratio, calculate ratio of each projected image in total incident intensity；According to each projected image in total incident intensity
Ratio and total incident intensity calculate the mean incident intensity of each projected image.
The present invention also proposes a kind of Cone-Beam CT incident intensity computing device, comprising: for according to the total of multiple projected images
The correction coefficient of dosage and incident intensity and dosage obtains the module of total incident intensity of multiple projected image；Based on
Calculate the module of the representative gray value of each projected image；For the representative gray value according to each projected image, calculating should
The module of ratio in multiple projected images between the incident intensity of every two projected image；And for total incident strong according to this
Ratio between degree and the incident intensity of every two projected image, calculates the module of the mean incident intensity of each projected image.
Compared with prior art, the present invention has the accuracy for improving the calculating of projected image incident intensity, improves figure
Image quality amount.And this invention simplifies the special designing that ionisation chamber is directed to imaging small-signal, cost has been saved.
Detailed description of the invention
Fig. 1 is the basic structure of radiotherapy system according to some embodiments of the present invention.
Fig. 2 is the configuration diagram of data processing computer according to some embodiments of the present invention.
Fig. 3 is Cone-Beam CT incident intensity calculation method flow chart according to some embodiments of the present invention.
Fig. 4 is the Cone-Beam CT incident intensity calculation method flow chart of other embodiments according to the present invention.
Fig. 5 A is the sum of the fan angle simulated in modified Shepp-Logan die body and the corresponding attenuation coefficient of each angle
The schematic diagram of relationship.
Fig. 5 B is the schematic diagram of the relationship of the sum of the fan angle simulated in strip die body and the corresponding attenuation coefficient of each angle.
Fig. 6 is the analog simulation result schematic diagram done according to the method for the present invention.
Specific embodiment
For the above objects, features and advantages of the present invention can be clearer and more comprehensible, below in conjunction with attached drawing to tool of the invention
Body embodiment elaborates.
In the following description, numerous specific details are set forth in order to facilitate a full understanding of the present invention, but the present invention can be with
It is different from other way described herein using other and implements, therefore the present invention is by the limit of following public specific embodiment
System.
As shown in the application and claims, unless context clearly prompts exceptional situation, " one ", "one", " one
The words such as kind " and/or "the" not refer in particular to odd number, may also comprise plural number.It is, in general, that term " includes " only prompts to wrap with "comprising"
Include clearly identify the step of and element, and these steps and element do not constitute one it is exclusive enumerate, method or apparatus
The step of may also including other or element.
Although the application is made that various references to the certain module in system according to an embodiment of the present application, however,
Any amount of disparate modules can be used and be operated on imaging system and/or processor.The module is only illustrative
, and disparate modules can be used in the different aspect of the system and method.
Flow chart used herein is used to illustrate operation performed by system according to an embodiment of the present application.It should
Understand, before or operation below not necessarily accurately carry out in sequence.On the contrary, can be handled according to inverted order or simultaneously
Various steps.Meanwhile or during other operations are added to these, or from these processes remove a certain step or number step operation.
The embodiment of the present invention describes Cone-Beam CT incident intensity calculation method and device, and single projected image can be improved and enter
Penetrate the accuracy of Strength co-mputation.This method and apparatus can be for kV-CBCT system, be also possible to for MV-CBCT system
System.Of course it is to be understood that application here is merely exemplary, and as long as not disagreed with the principle of the present invention, the present invention
It may be also used in other occasions.
It is usually to implement in radiotherapy (hereinafter radiotherapy) system that Cone-Beam CT incident intensity, which calculates,.Fig. 1 is basis
The basic structure of the radiotherapy system of some embodiments of the invention.Refering to what is shown in Fig. 1, radiotherapy system 100 may include that straight line adds
Fast device 101, collimator 102, electronic portal image device (electronic portal imaging device, EPID) 103
With data processing computer 104.Linear accelerator 101 is mounted on fixed position, can produce the ray of high level (usually
Megavolt grade), radiotherapy is carried out to the patient on hospital bed.Collimator 102 is mounted in the treatment head of system 100, for limiting
Radiation scope, to protect the normal tissue outside target area and make to jeopardize organ from irradiation.Electronic portal image device 103 is located at straight
The opposite location of line accelerator, for acquiring cone beam projection image.Linear accelerator 101 is towards electronic portal image device 103
Ray is issued, electronic portal image device 103 receives the X-ray across patient region to generate related tissue of patient density information
Projected image.In CBCT irradiation process, linear accelerator 101 can be in certain angle range (for example, 0-360 degree) inward turning
Turn, irradiates patient body from different perspectives.Electronic portal image device 103 correspondingly can incude ray in different location, and raw
At a series of projected image of different angles.Data processing computer 104 receives a series of throwings from electronic portal image device
Shadow image handles these projected images as required.
Fig. 2 is that the computer collocations framework of data processing computer 104 according to some embodiments of the present invention shows
It is intended to.As shown in Fig. 2, computer 200 can be implemented the current data processing one or more components of computer, module, unit,
Subelement.In addition, data processing computer 104 can by computer 200 by its hardware device, software program, firmware and
Their combination is realized.The calculating that this computer can be the computer of a general purpose or one has a specific purpose
Machine.Two kinds of computers can be used for realizing the particular system in the present embodiment.For convenience's sake, it is only depicted in Fig. 3
One computer, but the described correlation computer function that data processing information needed is provided of the present embodiment be can with point
The mode of cloth is implemented, the processing load of decentralized system by one group of similar platform.
As shown in Fig. 2, computer 200 may include internal communication bus 210, processor (processor) 220 is read-only to deposit
Reservoir (ROM) 230, random access memory (RAM) 240, communication port 250, input output assembly 260, hard disk 270, and use
Family interface 280.Internal communication bus 210 can realize the data communication of 200 inter-module of computer.Processor 220 can execute journey
Any function, component, the module, unit, son list of data processing computer 104 described in application herein are completed in sequence instruction
Member.Processor 220 can be made of one or more processors.Computer 200 and system 100 may be implemented in communication port 250
Data communication between other component (such as electronic portal image device 103).Computer 200 can also include various forms of journeys
Sequence storage element and data storage element, such as hard disk 270, read-only memory (ROM) 230, random access memory (RAM)
240, it stores computer disposal and/or communicates possible program performed by the various data files used and processor 220
Instruction.Input output assembly 260 support computer 200 and 100 other assemblies of system (such as electronic portal image device 103) it
Between input/output data stream.
Data processing computer 104 implements Cone-Beam CT incident intensity calculation method and device of the invention.Fig. 3 is according to this
The Cone-Beam CT incident intensity calculation method flow chart of some embodiments of invention.Refering to what is shown in Fig. 3, method 300 includes following step
It is rapid:
Step 301, it according to the correction coefficient of the accumulated dose of multiple projected images and incident intensity and dosage, obtains multiple
Total incident intensity of projected image；
In step 302, the representative gray value of each projected image is calculated；
In step 303, according to the representative gray value of each projected image, calculates every two in multiple projected images and project
Ratio between the incident intensity of image；
It is calculated each in step 304 according to the ratio between total incident intensity and the incident intensity of every two projected image
The mean incident intensity of projected image.
Step 301 specifically, is the correction coefficient Coef for being previously obtained incident intensity and dosage, reuses multiple projections
The accumulated dose D of imagetotalTotal figure is calculated as incident intensity Isum=CoefDtotal.For the example of MV-CBCT, school
Positive coefficient Coef can be obtained by absolute dosages instrument.
In one embodiment, in step 302, the logarithm of the gray value of each pixel for the projected image that can add up.Tool
Body method is:
In above formula, k represents projected image serial number, biIndicate that the gray value of each pixel, i indicate pixel serial number, m is whole
The pixel quantity of a projected image.
In another embodiment, the gray value of each pixel on the transverse center hatching line for the projected image that can also add up
Logarithm.Specific method is:
In above formula, k represents projected image serial number, biIndicate that the gray value of each pixel, i indicate pixel serial number, [m1,
M2] it is pixel coverage on transverse center hatching line.Here, the reason of selecting each pixel on the transverse center hatching line of projected image
It is that the gray value of the pixel on this hatching line is more acurrate, therefore the calculating of subsequent incident intensity ratio can be more accurate.It is replacing
For the regional area that in embodiment, also can choose in projected image comprising transverse center hatching line, add up wherein each pixel
Gray value logarithm, as representative gray value.
In step 303, it according to the representative gray value of each projected image, calculates every two in multiple projected images and throws
The method of ratio between the incident intensity of shadow image is:
I in above formulak1Represent the incident intensity of the first projected image, Ik2Represent the incident intensity of the second projected image, Ck1Generation
The representative gray value of the first projected image of table, Ck2The representative gray value of the second projected image is represented, n represents total voxel
Number.
And so on, the ratio in available multiple projected images, between the incident intensity of any two projected image.
In step 304, according to the obtained proportionate relationship of step 303, available each projected image is total incident
Ratio in intensity.Further, due to:
Ik1+Ik2+…+IkK=Isum (4)
Also, IsumIt obtains in step 301, further according to ratio of each projected image in total incident intensity, just
Available Ik1,Ik2…,IkK。
Specifically, above-mentioned formula (3) is obtained by:
A ray to a point being irradiated to from linear accelerator 101 on electronic portal image device 103,
In above formula, biRepresent i-th point of gray value on electronic portal image device 103, IkIndicate kth image
Incident intensity, aijIt is the element in projection matrix, is the length that ray passes through each voxel, represents j-th of voxel and electronics is penetrated
The contribution that 103 i-th point of wild device for image, μjThe attenuation coefficient of j-th of voxel is represented, n represents the total voxel for rebuilding object
Number.
Logarithm is taken to above formula (1), is obtained
To each irradiating angle θ, linear accelerator 101 is irradiated to all rays on electronic portal image device 103 and asks
With obtain the representative gray value for k-th of projected image for corresponding to this angle:
For infinite ray, it is easy to get
In the present example it is assumed that the element value of projection matrix are as follows:
Define TkAre as follows:
Here, suppose that TkTo it is angled be essentially identical.Above-mentioned conclusion can be verified by two kinds of die bodys,
A kind of die body is modified Shepp-Logan die body (Modified Shepp-Logan Phantom), and another die body is item
Shape die body (Bar Phantom).
It specifically, is the Shepp-Logan die body schematic diagram of modification referring to Fig. 5 A, Fig. 5 A, wherein abscissa indicates fan
Angle, that is, from 0 degree to 360 degree, ordinate indicates the sum of the attenuation coefficient of the corresponding all voxels of each angle, that is, Tk.From Fig. 5 A
It can be seen that TkVariation within 1%.
Referring back to Fig. 5 B, Fig. 5 B is strip die body schematic diagram, wherein abscissa indicates fan angle, that is, from 0 degree to 360 degree,
Ordinate indicates the sum of the attenuation coefficient of the corresponding all voxels of each angle, that is, Tk, as can be seen from Figure 5B, TkVariation also exist
Within 1%.
Based on the verifying of both the above die body, above-mentioned hypothesis can be set up.
Furthermore according to formula:
Further according to above-mentioned hypothesis, that is, Tk1=Tk2, and then available above-mentioned formula (3):
Although here, the T in the verifying of two kinds of die bodyskVariation it is smaller, but this is not indicated, aforementioned hypothesis is limited to
TkVariation within 1%, it is very reliable that the verifyings of both die bodys, which has only proved aforementioned hypothesis from side,.Even if Tk
Variation be greater than 1%, do not influence aforementioned hypothesis of the invention still.
Equally distributed random noise is added to IkValue, to restore original value from these above-mentioned equatioies.Such as Fig. 6 institute
Show, Fig. 6 shows a kind of simulation result, and wherein abscissa is fan angle, and from 0 degree to 360 degree, ordinate is the corresponding I of each angle0
Value.Specifically, in modified Shepp-Logan die body, multiple I are generated at random0Value (represents ideal incident intensity), is scheming
In indicated with circle, since the attenuation coefficient of the die body is it is known that therefore, data for projection can be obtained by calculation (for example, according to
Formula (5))；Using the data for projection of front simulation calculation, calculated again by aforementioned method 300 of the invention in turn each
I’0Value is simultaneously indicated in figure with cross.In the figure it can be found that the probability that is overlapped with circle of cross is very high, that is, calculate
The I ' arrived0Value and ideal value I0Closely.For the Shepp-Logan die body of modification, error is about 0.65%.For figure
For rebuilding, this error is negligible.
Fig. 4 is the Cone-Beam CT incident intensity calculation method flow chart of other embodiments according to the present invention.With reference to Fig. 4 institute
Show, method 400 the following steps are included:
Step 401, it according to the correction coefficient of the accumulated dose of multiple projected images and incident intensity and dosage, obtains multiple
Total incident intensity of projected image；
In step 402, the representative gray value of each projected image is calculated；
In step 403, according to the representative gray value of each projected image, calculates every two in multiple projected images and project
Ratio between the incident intensity of image；
It is calculated each in step 404 according to the ratio between total incident intensity and the incident intensity of every two projected image
The mean incident intensity of projected image.
In step 405, three-dimensional image reconstruction is carried out using the mean incident intensity of each projected image, obtains each voxel
Attenuation coefficient；
In step 406, the mean incident intensity of each projected image is updated according to the attenuation coefficient of each voxel；
In step 407, judge whether the mean incident intensity of each projected image meets the condition of convergence, if it is returns to step
Rapid 405, otherwise terminate.By this iterative process, the calculating of mean incident intensity can be allowed more accurate.
In a step 406, the formula of mean incident intensity is updated are as follows:
In step 407, the condition of convergence is, for example, | I(p+1)-I(p)|<Ith, wherein I(p)It is that the incidence that pth time calculates is strong
Degree, I(p+1)It is the incident intensity of pth+1 time calculating, IthIt is preset threshold value.
The above method 300,400 can be computer program, be stored in the program storage unit of computer 200, such as firmly
Disk 270, read-only memory (ROM) 230, in random access memory (RAM) 240, processor 220, which is loaded into, simultaneously executes this journey
Sequence.
When data processing computer 104 includes the above method 300 or 400, as a kind of Cone-Beam CT incident intensity calculates dress
It sets, including memory and processor.The method 300 or 400 of form of computer readable instructions is stored in memory.Processor is then
The computer-readable instruction is executed with implementation method 300 or 400.
From another viewpoint, Cone-Beam CT incident intensity computing device may also comprise: for according to the total of multiple projected images
The correction coefficient of dosage and incident intensity and dosage obtains the module of total incident intensity of multiple projected image；Based on
Calculate the module of the representative gray value of each projected image；For the representative gray value according to each projected image, calculating should
The module of ratio in multiple projected images between the incident intensity of every two projected image；And for total incident strong according to this
Ratio between degree and the incident intensity of every two projected image, calculates the module of the mean incident intensity of each projected image.
Basic conception is described above, it is clear that those skilled in the art, foregoing invention discloses only
As an example, and not constituting the restriction to the application.Although do not clearly state herein, those skilled in the art may
The application is carry out various modifications, improve and is corrected.Such modification, improvement and amendment are proposed in this application, so such
Modification improves, corrects the spirit and scope for still falling within the application example embodiment.
Meanwhile the application has used particular words to describe embodiments herein.Such as " one embodiment ", " one implements
Example ", and/or " some embodiments " mean a certain feature relevant at least one embodiment of the application, structure or feature.Cause
This, it should be highlighted that and it is noted that " embodiment " or " an implementation referred to twice or repeatedly in this specification in different location
Example " or " alternate embodiment " are not necessarily meant to refer to the same embodiment.In addition, in one or more embodiments of the application
Certain features, structure or feature can carry out combination appropriate.
In addition, it will be understood by those skilled in the art that the various aspects of the application can be by several with patentability
Type or situation are illustrated and described, the combination or right including any new and useful process, machine, product or substance
Their any new and useful improvement.Correspondingly, the various aspects of the application can completely by hardware execute, can be complete
It is executed, can also be executed by combination of hardware by software (including firmware, resident software, microcode etc.).Hardware above is soft
Part is referred to alternatively as " data block ", " module ", " engine ", " unit ", " component " or " system ".In addition, the various aspects of the application
The computer product being located in one or more computer-readable mediums may be shown as, which includes computer-readable program
Coding.
Although the present invention is described with reference to current specific embodiment, those of ordinary skill in the art
It should be appreciated that above embodiment is intended merely to illustrate the present invention, can also make in the case where no disengaging spirit of that invention
Various equivalent change or replacement out, therefore, as long as to the variation of above-described embodiment, change in spirit of the invention
Type will all be fallen in the range of following claims.
Claims (9)
1. a kind of Cone-Beam CT incident intensity calculation method, comprising the following steps:
A. according to the correction coefficient of the accumulated dose of multiple projected images and incident intensity and dosage, multiple projected image is obtained
Total incident intensity；
B. the representative gray value of each projected image is calculated, which includes: the gray scale of each pixel of cumulative projected image
The logarithm of value, or
The logarithm of the gray value of each pixel on the transverse center hatching line of cumulative projected image, or
The logarithm of the gray value of each pixel of at least one regional area of the cumulative transverse center hatching line comprising projected image；
C. according to the representative gray value of each projected image, the incidence of every two projected image in multiple projected image is calculated
Ratio between intensity；And
D. according to the ratio between total incident intensity and the incident intensity of every two projected image, each projected image is calculated
Mean incident intensity.
2. the method as described in claim 1, which is characterized in that after step d further include:
E. three-dimensional image reconstruction is carried out using the mean incident intensity of each projected image, obtains the attenuation coefficient of each voxel；
F. the mean incident intensity of each projected image is updated according to the attenuation coefficient of each voxel；
G. iteration carries out step e and f, until the mean incident intensity of each projected image meets the condition of convergence.
3. the method as described in claim 1, which is characterized in that according to the representative gray value of each projected image, calculating should
The method of ratio in multiple projected images between the incident intensity of every two projected image are as follows:
Wherein Ik1Represent the incident intensity of the first projected image, Ik2Represent the incident intensity of the second projected image, Ck1Represent first
The representative gray value of projected image, Ck2The representative gray value of the second projected image is represented, n represents total voxel number.
4. the method as described in claim 1, which is characterized in that according to the incidence of total incident intensity and every two projected image
Ratio between intensity, the step of calculating the mean incident intensity of each projected image include:
According to the ratio between the incident intensity of every two projected image, ratio of each projected image in total incident intensity is calculated
Example；
Being averaged for each projected image is calculated according to ratio of each projected image in total incident intensity and total incident intensity
Incident intensity.
5. a kind of Cone-Beam CT incident intensity computing device, comprising:
Memory stores computer-readable instruction；
Processor executes the computer-readable instruction to implement following step:
A. according to the correction coefficient of the accumulated dose of multiple projected images and incident intensity and dosage, multiple projected image is obtained
Total incident intensity；
B. the representative gray value of each projected image is calculated, which includes: the gray scale of each pixel of cumulative projected image
The logarithm of value, or
The logarithm of the gray value of each pixel on the transverse center hatching line of cumulative projected image, or
The logarithm of the gray value of each pixel of at least one regional area of the cumulative transverse center hatching line comprising projected image；
C. according to the representative gray value of each projected image, the incidence of every two projected image in multiple projected image is calculated
Ratio between intensity；And
D. according to the ratio between total incident intensity and the incident intensity of every two projected image, each projected image is calculated
Mean incident intensity.
6. Cone-Beam CT incident intensity computing device as claimed in claim 5, which is characterized in that processor also executes the computer
Readable instruction is to implement following step:
E. three-dimensional image reconstruction is carried out using the mean incident intensity of each projected image, obtains the attenuation coefficient of each voxel；
F. the mean incident intensity of each projected image is updated according to the attenuation coefficient of each voxel；
G. iteration carries out step e and f, until the mean incident intensity of each projected image meets the condition of convergence.
7. Cone-Beam CT incident intensity computing device as claimed in claim 5, which is characterized in that according to the generation of each projected image
Table gray value, the method for calculating the ratio in multiple projected image between the incident intensity of every two projected image are as follows:
Wherein Ik1Represent the incident intensity of the first projected image, Ik2Represent the incident intensity of the second projected image, Ck1Represent first
The representative gray value of projected image, Ck2The representative gray value of the second projected image is represented, n represents total voxel number.
8. Cone-Beam CT incident intensity computing device as claimed in claim 5, which is characterized in that according to total incident intensity and often
Ratio between the incident intensity of two projected images, the step of calculating the mean incident intensity of each projected image include:
According to the ratio between the incident intensity of every two projected image, ratio of each projected image in total incident intensity is calculated
Example；
Being averaged for each projected image is calculated according to ratio of each projected image in total incident intensity and total incident intensity
Incident intensity.
9. a kind of Cone-Beam CT incident intensity computing device, comprising:
For obtaining multiple perspective view according to the accumulated dose and incident intensity of multiple projected images and the correction coefficient of dosage
The module of total incident intensity of picture；
It include cumulative for the step of calculating the module of the representative gray value of each projected image, calculating the representativeness gray value
The logarithm of the gray value of each pixel of projected image, or
The logarithm of the gray value of each pixel on the transverse center hatching line of cumulative projected image, or
The logarithm of the gray value of each pixel of at least one regional area of the cumulative transverse center hatching line comprising projected image；
For the representative gray value according to each projected image, entering for every two projected image in multiple projected image is calculated
Penetrate the module of the ratio between intensity；And
For calculating each projected image according to the ratio between total incident intensity and the incident intensity of every two projected image
Mean incident intensity module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611262008.0A CN106709913B (en) | 2016-12-30 | 2016-12-30 | Cone-Beam CT incident intensity calculation method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611262008.0A CN106709913B (en) | 2016-12-30 | 2016-12-30 | Cone-Beam CT incident intensity calculation method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106709913A CN106709913A (en) | 2017-05-24 |
| CN106709913B true CN106709913B (en) | 2019-10-08 |
Family
ID=58906374
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611262008.0A Active CN106709913B (en) | 2016-12-30 | 2016-12-30 | Cone-Beam CT incident intensity calculation method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106709913B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107730550B (en) * | 2017-10-31 | 2019-12-06 | 华中科技大学 | detection method of puncture biopsy needle in ultrasonic image |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102648857A (en) * | 2011-02-23 | 2012-08-29 | 西门子公司 | Method and computer system for scattered beam correction in a multi-source CT |
| KR20140004433A (en) * | 2012-07-02 | 2014-01-13 | 충남대학교산학협력단 | Cone beam ct apparatus using low dose x-ray |
| CN106204548A (en) * | 2016-06-30 | 2016-12-07 | 上海联影医疗科技有限公司 | Image resolution method and device |
-
2016
- 2016-12-30 CN CN201611262008.0A patent/CN106709913B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102648857A (en) * | 2011-02-23 | 2012-08-29 | 西门子公司 | Method and computer system for scattered beam correction in a multi-source CT |
| KR20140004433A (en) * | 2012-07-02 | 2014-01-13 | 충남대학교산학협력단 | Cone beam ct apparatus using low dose x-ray |
| CN106204548A (en) * | 2016-06-30 | 2016-12-07 | 上海联影医疗科技有限公司 | Image resolution method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106709913A (en) | 2017-05-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhu et al. | Scatter correction for cone‐beam CT in radiation therapy | |
| US7567647B1 (en) | Source array translation for digital tomosynthesis | |
| JP2022509306A (en) | Methods and equipment to improve scatter evaluation and scatter correction in imaging | |
| Ljungberg et al. | 3D absorbed dose calculations based on SPECT: evaluation for 111-In/90-Y therapy using Monte Carlo simulations | |
| US8433119B2 (en) | Extension of the field of view of a computed tomography system in the presence of interfering objects | |
| US7865005B2 (en) | Iterative reconstruction of multiple-peak isotope images | |
| Wu et al. | Metal artifact correction for x‐ray computed tomography using kV and selective MV imaging | |
| McCowan et al. | An in vivo dose verification method for SBRT–VMAT delivery using the EPID | |
| Stute et al. | Monte Carlo simulations of clinical PET and SPECT scans: impact of the input data on the simulated images | |
| Paudel et al. | Evaluation of normalized metal artifact reduction (NMAR) in kVCT using MVCT prior images for radiotherapy treatment planning | |
| Killoran et al. | Motion artifacts occurring at the lung/diaphragm interface using 4D CT attenuation correction of 4D PET scans | |
| Berndt et al. | Application of single-and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy | |
| Neppl et al. | Measurement‐based range evaluation for quality assurance of CBCT‐based dose calculations in adaptive proton therapy | |
| CN106709913B (en) | Cone-Beam CT incident intensity calculation method and device | |
| Malusek et al. | A model‐based iterative reconstruction algorithm DIRA using patient‐specific tissue classification via DECT for improved quantitative CT in dose planning | |
| CN110914868A (en) | System and method for scatter calibration | |
| Ayyangar et al. | Do we need Monte Carlo treatment planning for linac based radiosurgery? A case study | |
| CN111001097B (en) | Radiotherapy dose evaluation system, device and storage medium | |
| CN109959669A (en) | Sill decomposition method and device and computer readable storage medium | |
| Robar et al. | Volume‐of‐interest cone‐beam CT using a 2.35 MV beam generated with a carbon target | |
| Somasundaram et al. | Development and validation of an open source Monte Carlo dosimetry model for wide‐beam CT scanners using Fluka | |
| Palaniappan et al. | A 2D-3D Deformable image registration framework for proton radiographies in adaptive radiation therapy | |
| Souleyman et al. | Impact of acquisition protocols on accuracy of dose calculation based on xvi cone beam computed tomography | |
| Hyytiäinen | 4D dose calculation in pencil beam scanning proton therapy | |
| CN109846501B (en) | Scattered ray correction method and terminal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 201807 2258 Chengbei Road, Jiading District, Shanghai Patentee after: Shanghai Lianying Medical Technology Co., Ltd Address before: No. 802258 Jiading Road, Shanghai Patentee before: SHANGHAI UNITED IMAGING HEALTHCARE Co.,Ltd. |