WO2009093305A1 - ポジトロンct装置 - Google Patents
ポジトロンct装置 Download PDFInfo
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- WO2009093305A1 WO2009093305A1 PCT/JP2008/050802 JP2008050802W WO2009093305A1 WO 2009093305 A1 WO2009093305 A1 WO 2009093305A1 JP 2008050802 W JP2008050802 W JP 2008050802W WO 2009093305 A1 WO2009093305 A1 WO 2009093305A1
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- system matrix
- positron
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- lor
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- 239000011159 matrix material Substances 0.000 claims abstract description 76
- 238000004364 calculation method Methods 0.000 claims abstract description 47
- 229940121896 radiopharmaceutical Drugs 0.000 claims description 6
- 239000012217 radiopharmaceutical Substances 0.000 claims description 6
- 230000002799 radiopharmaceutical effect Effects 0.000 claims description 6
- 230000005855 radiation Effects 0.000 claims description 5
- 230000005251 gamma ray Effects 0.000 description 24
- 238000002600 positron emission tomography Methods 0.000 description 18
- 238000002591 computed tomography Methods 0.000 description 13
- 238000010586 diagram Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 9
- 238000010521 absorption reaction Methods 0.000 description 4
- 238000004422 calculation algorithm Methods 0.000 description 4
- 238000007476 Maximum Likelihood Methods 0.000 description 3
- 238000003745 diagnosis Methods 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 230000012447 hatching Effects 0.000 description 3
- 238000009206 nuclear medicine Methods 0.000 description 3
- 238000010606 normalization Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 210000001015 abdomen Anatomy 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000008827 biological function Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000005316 response function Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000003325 tomography Methods 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/29—Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
- G01T1/2914—Measurement of spatial distribution of radiation
- G01T1/2985—In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis)
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
- A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
- A61B6/03—Computed tomography [CT]
- A61B6/037—Emission tomography
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T11/00—2D [Two Dimensional] image generation
- G06T11/003—Reconstruction from projections, e.g. tomography
- G06T11/006—Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2211/00—Image generation
- G06T2211/40—Computed tomography
- G06T2211/424—Iterative
Definitions
- the present invention relates to a positron CT apparatus that detects radiation emitted from a positron radiopharmaceutical administered into a subject and generates a positron distribution image as an image.
- a positron CT device ie, a PET (Positron EmissionographyTomography) device, detects positrons (Positron), that is, a plurality of ⁇ -rays generated by annihilation of positrons, and a plurality of detectors simultaneously detect ⁇ -rays ( In other words, only when simultaneous counting is performed, the image of the subject is reconstructed.
- positron positron
- the process of drug accumulation in the target tissue is measured over time, whereby quantitative measurement of various biological functions is possible. Therefore, the image obtained by the PET apparatus has function information.
- a positron (positron) radioactive isotope for example, 15 O, 18 F, 11 C, etc.
- a detector array comprising a number of ⁇ -ray detectors arranged in a ring shape so as to surround the body axis that is the longitudinal axis of the subject.
- calculation is performed by a computer in the same manner as in ordinary X-ray CT (Computed Tomography), and the image is specified in the plane, and an image of the subject is created.
- Non-Patent Documents 1 and 2 When reconstructing an image, the following method is used (for example, see Non-Patent Documents 1 and 2).
- LOR is a virtual straight line connecting two detectors that simultaneously count.
- the LOR is a tube-like region connecting two detectors that detect two ⁇ -ray photons generated from each voxel and emitted in opposite directions. That is.
- the present invention has been made in view of such circumstances, and an object thereof is to provide a positron CT apparatus capable of realizing high-speed image reconstruction.
- the present invention has the following configuration. That is, the positron CT apparatus according to the present invention includes a plurality of detectors that detect radiation emitted from a positron radiopharmaceutical administered into a subject and output an electrical signal, and the two based on the electrical signal.
- a coincidence counting circuit for detecting that radiation is simultaneously observed in the detector; a system matrix calculating means for calculating a system matrix based on an output of the coincidence counting circuit; and A positron CT apparatus having reconstruction means for generating a distribution image as an image, and calculating a crossing range for obtaining a crossing range of a coincidence LOR, which is a virtual straight line connecting the two detectors for simultaneous counting, and a pixel
- the system matrix calculation means further includes a means for calculating a system matrix by calculating an element in the system matrix included in the crossover range. It is characterized in that for obtaining the matrix.
- the crossing range calculation means obtains the crossing range of the coincidence counting LOR, which is a virtual straight line connecting two detectors for simultaneous counting, and the pixel.
- the elements in the system matrix of all data in the field of view are conventionally calculated to obtain the system matrix.
- the system matrix calculation means When calculating the system matrix, the system matrix is obtained by calculating the elements in the system matrix included in the crossover range described above. Based on the system matrix, the reconstruction means generates a positron distribution image as an image.
- the data necessary for the calculation of the system matrix can be reduced by reducing the data required for the system matrix from the entire data in the conventional field of view to the data for the crossing range.
- the efficiency of access to the storage means for storing the crossover range is reduced by the reduced amount, and the calculation of the system matrix is also made efficient. As a result, speeding up of image reconstruction can be realized.
- the above-described pixel is composed of a three-dimensional voxel
- the above-described crossing range calculating means approximates a parallel hexahedron circumscribing the detectors at both ends of the LOR to provide a three-dimensional crossing. Find the range.
- To determine the three-dimensional crossover range consider a parallelepiped that is as small as possible, including detectors at both ends of the LOR.
- the parallel hexahedron circumscribing the detector described above becomes the smallest parallel hexahedron, and a three-dimensional crossover is performed by approximating the voxel crossing the parallel hexahedron as a voxel that may cross the LOR.
- a range can be determined.
- each surface forming the parallelepiped is preferably rectangular or square.
- the cross section of the parallel hexahedron with the LOR orthogonal is also rectangular or square, and each side of the cross section is also parallel to the voxel boundary surface.
- the size is also a three-dimensional array of “long side ⁇ short side ⁇ one side of field of view (FOV)”, and the creation of a program related to the initialization work necessary for the calculation of the system matrix described above is simplified.
- the crossover range calculation means obtains the crossover range of the coincidence count LOR, which is a virtual straight line connecting two detectors to be simultaneously counted, and the pixel
- the system matrix calculation means includes: When calculating the system matrix, the system matrix is obtained by calculating elements in the system matrix included in the above-described crossover range. As a result, speeding up of image reconstruction can be realized.
- FIG. 1 is a side view and block diagram of a PET (Positron Emission Tomography) apparatus according to an embodiment. It is a schematic perspective view of a gamma ray detector.
- (A), (b) is the schematic diagram which showed the simultaneous count in the gamma ray detector with which it uses for description of the absorption probability to a micro area
- FIG. 1 is a side view and a block diagram of a PET (Positron Emission Tomography) apparatus according to an embodiment
- FIG. 2 is a schematic perspective view of a ⁇ -ray detector.
- the PET apparatus includes a top plate 1 on which a subject M is placed as shown in FIG.
- the top plate 1 is configured to move up and down and translate along the body axis Z of the subject M.
- the subject M placed on the top 1 is scanned from the head to the abdomen and foot sequentially through the opening 2a of the gantry 2, which will be described later. Get the image. Note that there is no particular limitation on the scanned part and the scanning order of each part.
- the PET apparatus includes a gantry 2 having an opening 2a and a ⁇ -ray detector 3.
- the ⁇ -ray detector 3 is arranged in a ring shape so as to surround the body axis Z of the subject M, and is embedded in the gantry 2.
- the ⁇ -ray detector 3 corresponds to the detector in the present invention.
- the PET apparatus includes a top board drive unit 4, a controller 5, an input unit 6, an output unit 7, a memory unit 8, a coincidence circuit 9, a cross range calculation unit 10, and a system matrix calculation unit 11.
- the top plate driving unit 6 is a mechanism for driving the top plate 1 so as to perform the above-described movement, and is configured by a motor or the like not shown.
- the crossing range calculation unit 10 corresponds to the crossing range calculation unit in the present invention
- the system matrix calculation unit 11 corresponds to the system matrix calculation unit in the present invention
- the reconstruction unit 12 corresponds to the reconstruction unit in the present invention. To do.
- the controller 5 comprehensively controls each part constituting the PET apparatus according to the present embodiment.
- the controller 5 includes a central processing unit (CPU).
- the input unit 6 sends data and commands input by the operator to the controller 5.
- the input unit 6 includes a pointing device represented by a mouse, a keyboard, a joystick, a trackball, a touch panel, and the like.
- the output unit 7 includes a display unit represented by a monitor, a printer, and the like.
- the memory unit 8 includes a storage medium represented by ROM (Read-only Memory), RAM (Random-Access Memory), and the like.
- the count value (count) simultaneously counted by the coincidence circuit 9 the data relating to the coincidence counting such as the detector pair consisting of the two ⁇ -ray detectors 3 and the LOR, and the cross range calculation unit 10
- the data for the obtained crossing range, the system matrix obtained by the system matrix calculation unit 11, the image processed by the reconstruction unit 12, and the like are written and stored in the RAM, and read from the RAM as necessary.
- the cross range memory unit 8a capable of storing the data for the cross range obtained by the cross range calculation unit 10 is provided in the memory area in the memory unit 8, and the data for the cross range is stored.
- the ROM stores in advance a program for performing imaging including various types of nuclear medicine diagnosis, and the controller 5 executes the program to perform nuclear medicine diagnosis according to the program.
- the crossing range calculation unit 10, the system matrix calculation unit 11, and the reconstruction unit 12 are, for example, a program stored in a ROM of a storage medium represented by the memory unit 8 or the like described above, or a pointing device represented by the input unit 6 or the like. This is realized by the controller 5 executing the command input in (1).
- the ⁇ -rays generated from the subject M to which the radiopharmaceutical is administered are converted into light by the scintillator block 31 (see FIG. 2) of the ⁇ -ray detector 3, and the converted light is photoelectron of the ⁇ -ray detector 3.
- a multiplier tube (PMT: Photo Multiplier Tube) 33 (see FIG. 2) multiplies and converts it into an electrical signal.
- the electric signal is sent to the coincidence counting circuit 9 as image information (pixel value, that is, a count value simultaneously counted by the ⁇ -ray detector 3).
- the coincidence circuit 9 checks the position of the scintillator block 31 (see FIG. 2) and the incident timing of the ⁇ rays, and only when the ⁇ rays are simultaneously incident on the two scintillator blocks 31 on both sides of the subject M. The sent image information is determined as appropriate data.
- the coincidence counting circuit 10 rejects. That is, the coincidence counting circuit 9 detects that ⁇ rays are simultaneously observed in the two ⁇ ray detectors 3 based on the above-described electrical signal.
- the image information sent to the coincidence counting circuit 9 is sent to the crossover range calculation unit 10, the system matrix calculation unit 11, and the reconstruction unit 12.
- the reconstruction unit 12 performs reconstruction based on the system matrix obtained by the system matrix calculation unit 11 and obtains an image of the subject M. Specifically, the reconstruction unit 12 generates a positron distribution image as an image based on the system row example. The image is sent to the output unit 7 via the controller 5. In this manner, nuclear medicine diagnosis is performed based on the image obtained by the reconstruction unit 12. Specific functions of the crossing range calculation unit 10 and the system matrix calculation unit 11 will be described later.
- the ⁇ -ray detector 3 includes a scintillator block 31, a light guide 32 optically coupled to the scintillator block 31, and photoelectrons optically coupled to the light guide 32.
- a multiplier (hereinafter simply abbreviated as “PMT”) 33 is provided.
- Each scintillator element constituting the scintillator block 31 converts ⁇ rays into light by emitting light with the incidence of ⁇ rays. By this conversion, the scintillator element detects ⁇ rays.
- Light emitted from the scintillator element is sufficiently diffused by the scintillator block 31 and input to the PMT 33 via the light guide 32.
- the PMT 33 multiplies the light converted by the scintillator block 31 and converts it into an electric signal.
- the electric signal is sent to the coincidence counting circuit 9 (see FIG. 1) as image information (pixel value) as described above.
- FIG. 3 is a schematic diagram showing coincidence counting with a ⁇ -ray detector for explaining the probability of absorption into a minute region
- FIG. 4 is an explanation of voxels that may cross LOR and a holding array.
- FIG. 5 is a schematic diagram of a parallelepiped circumscribing the ⁇ -ray detector
- FIG. 6 is a schematic diagram relating to a cross-section of the circumscribed hexahedron and voxel. 3 and 5, only the scintillator block 31 is illustrated as the ⁇ -ray detector 3, and the light guide 32 and the PMT 33 are not illustrated.
- Non-Patent Document 3 As shown in FIG. 3A, it is assumed that ⁇ -ray photons generated from the voxel ⁇ j are detected at the i-th LOR (L i ) with a probability of a ij .
- a drawing depicting S sub-LORs (indicated by a two-dot chain line in FIG. 3B) at an interval ⁇ L with respect to the target tube-shaped L i (indicated by a one-dot chain line in FIG. 3) is shown in FIG. b).
- the number of small areas divided by S the sub LOR, including L i of interest this time also becomes S.
- the sub-LORs are illustrated in parallel, but are not necessarily in parallel. Also, the sub-LORs need not be equally spaced.
- the probability that the ⁇ -ray emitted from the position r in the field of view becomes the i-th projection data is called a “detector response function (DRF)” (in FIG. 3B, “DRF ”) And h i (r).
- DPF detector response function
- h i (r) obtained by the above equation (1) is expressed as hi in a certain minute region s, and each sub-LOR including the target L i is a voxel.
- elements of the system matrix in (i.e. probability a ij) is the combined formula (2) below added to weighted length l js described above in DRF (h iS) expressed.
- a ij is expressed as the following formula (4) by the sum of the absorption probabilities a ij (s) .
- an array A (see FIG. 4) equal to the number of voxels J is prepared for each L i , and a ij (s) is added using the above equation (4).
- a certain a ij can be obtained.
- the crossover range calculation unit 10 lists in advance the voxels ⁇ j that may cross the LOR (L i ), and only a ij corresponding to this is listed.
- An array A ′ (see FIG. 4) is prepared, and a ij is obtained by adding a ij (s) using the above equation (4).
- the crossing range calculation unit 10 calculates LOR (L i ) and voxels.
- a holding array A ′ indicating the crossing range is obtained.
- Voxels ⁇ j that may cross LOR (L i ) are indicated by hatching in FIG.
- a three-dimensional crossing range is obtained by approximating with the parallelepiped HEX circumscribing the detectors 3 0 and 3 1 at both ends of the LOR.
- a parallelepiped HEX that includes detectors 3 0 and 3 1 at both ends of the LOR and is as small as possible.
- the parallel hexahedron HEX circumscribing the detectors 3 0 and 3 1 described above is the smallest parallel hexahedron, and there is a possibility that the voxel ⁇ j intersecting with the parallel hexahedron HEX may be crossed with LOR (L i ).
- LOR L i
- a three-dimensional crossover range can be obtained. That is, returning to FIG. 4, the aggregate of the minimum range of voxels ⁇ j including the parallelepiped HEX is the crossing range indicated by hatching in FIG. 4.
- each surface forming the parallelepiped is preferably set to be a rectangle or a square.
- the cross section of parallel hexahedron HEX in which LOR (L i ) is orthogonal is also rectangular or square, and each side of the cross section (in FIG. (Notation) is also parallel to the voxel interface.
- the cross section of the crossing range at this time is also indicated by hatching in FIG.
- the size is also a three-dimensional array of “long side ⁇ short side ⁇ one side of field of view (FOV)” (when the cross section is square, “(one side of cross section) 2 ⁇ one side of field of view (FOV)”). This simplifies the creation of a program related to the initialization work necessary for calculating the system matrix.
- the storage array A ′ thus obtained is written and stored in the cross range memory unit 8a (see FIG. 1) as cross range data. Then, when the system matrix is calculated by the system matrix calculation unit 11 (see FIG. 1), it is read from the cross range memory unit 8a. As described above, if data for the crossing range (holding array A ′) read from the crossing range memory unit 8a is prepared, a ij (s) is added using the above equation (4). The system matrix calculation unit 11 can obtain a ij that is an element in the system matrix.
- the reconstruction unit 12 performs reconstruction based on the system matrix obtained by the system matrix calculation unit 11.
- the reconstruction based on the system matrix will be described with reference to Non-Patent Document 1 described above.
- description will be made by applying a list-mode DRAMA method (Dynamic Row-Action Maximum Likelihood Algorithm).
- the reconstructed pixel value is x j
- x j is used by using a ij that is an element in the system matrix. Is represented by the following formulas (5) to (10).
- ⁇ k (q) in the equations (6) and (10) is a relaxation parameter
- C j in the equations (6) and (7) is a normalization matrix (normalization matrix).
- p qj is called “Blocking Factor”.
- the above equation (6) is expressed as x j (k, q + 1) using a ij obtained by the system matrix calculation unit 11 (see FIG. 1) and x j (k, q) obtained previously. Means seeking. Therefore, x j (k, 1) ,..., X j (k, M ⁇ 1) is sequentially obtained by repeatedly substituting into the above equation (6) using a ij and x j (k, 0).
- X j (k, M ⁇ 1) finally obtained is substituted into the above equation (8) to be carried up to x j (k + 1) .
- x j (k + 1) is used, and similarly using a ij and x j (k + 1,0) , the above (6)
- x j (k + 1 , 1) is sequentially obtained.
- k indicating the superscript of j is the number of successive approximations in the successive approximation expression representing the above expression (6). Note that the initial value x j (0) is set to x j (0) > 0.
- the initial value x j (0) is determined, and the determined x j (0) is substituted into the above equation (5) to obtain x j (0, 0) , and a ij and , X j (0,0) is repeatedly substituted into the above equation (6) to obtain x j (0,1) ,..., X j (0, M ⁇ 1) sequentially, X j (0, M ⁇ 1) finally obtained is substituted into the above equation (8) to be moved up to x j (1) .
- x j is sequentially incremented (x j (0) , x j (1) ..., X j (k) ).
- the number of times k is not particularly limited and may be set as appropriate.
- the reconstructing unit 12 (see FIG. 1) performs reconstruction by arranging x j finally obtained in this manner for each voxel v j corresponding thereto, and obtains an image of the subject M.
- the reconstruction based on the system matrix is not limited to the above-described DRAMA method, and may be a static (that is, static) RAMLA method (Row-Action Maximum Likelihood Algorithm) or an ML-EM method (Maximum Likelihood). Expectation Maximization) or OSEM method (Ordered Subset ML-EM) may be used. It is preferable that reconstruction is performed using a successive approximation method using a successive approximation expression such as the above formula (6).
- the crossover range calculation unit 10 obtains the crossover range of the coincidence count LOR, which is a virtual straight line connecting two detectors to be simultaneously counted, and the pixels. .
- the element a ij in the system matrix of all data in the field of view was calculated to obtain the system matrix
- the matrix calculation unit 10 calculates the system matrix by calculating the element a ij in the system matrix included in the crossing range stored in the crossing range memory unit 8a using the above equation (4). ing.
- the reconstruction unit 12 generates a positron distribution image as an image. Therefore, the data required prior to the calculation of the system matrix is reduced from all data (array A) in the conventional field of view to the data for the crossing range (holding array A ′), and is necessary for the calculation of the system matrix.
- the efficiency of the initialization work is simply increased by calculating the crossover range, the efficiency of access to the crossover range memory unit 8a for storing the crossover range is reduced by the amount reduced to the data for the crossover range, and the calculation of the system matrix is also performed. Increased efficiency. As a result, speeding up of image reconstruction can be realized.
- the present invention is not limited to the above embodiment, and can be modified as follows.
- the positron CT apparatus PET apparatus
- PET apparatus positron CT apparatus
- the pixel is formed of a three-dimensional voxel and approximated by a parallelepiped circumscribing the detectors at both ends of the LOR to obtain a three-dimensional crossing range.
- the pixel is a two-dimensional pixel ( It may be applied to the case of pixel).
- a two-dimensional crossing range may be obtained by approximating with a parallelogram or rectangle circumscribing the detectors at both ends of the LOR.
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Abstract
Description
Nakamura T, Kudo H: Derivation and implementation of ordered-subsets algorithms for list-mode PET data, IEEE Nuclear Science Symposium Conference Record: 1950-1954, 2005 Tanaka E, Kudo H: Subset-dependent relaxation in block-iterative algorithms for image reconstruction in emission tomography. In: Phys Med Biol 48, 1405-1422, 2003 高橋悠,山谷泰賀,小林哲哉,他 :近接撮影型DOI-PETの画像再構成における観測系モデルの検討.JAMIT AnnualMeeting 2006 講演予稿集,OP10-7 H. Tonami, K. Kitamura, M. Satoh, T. Tsuda, and Y. Kumazawa, "Sophisticated 32×32×4-Layer DOI Detector for High Resolution PEM Scanner," IEEE Medical Imaging Conference Record, pp. 3803-3807, 2007.
すなわち、この発明のポジトロンCT装置は、被検体内に投与されたポジトロン放射性薬剤から放出される放射線を検出して電気信号を出力する複数の検出器と、前記電気信号に基づいて、2つの前記検出器において放射線が同時観測されたことを検出する同時計数回路と、前記同時計数回路の出力に基づいて、システム行列を算出するシステム行列算出手段と、当該システム行例に基づいて、前記ポジトロンの分布画像を画像として生成する再構成手段とを有するポジトロンCT装置であって、前記同時計数する2つの検出器を結ぶ仮想上の直線である同時計数LORと画素との交叉範囲を求める交叉範囲算出手段を更に有し、前記システム行列算出手段は、前記交叉範囲に含まれる前記システム行列中の要素を演算することによりシステム行列を求めることを特徴とするものである。
10 … 交叉範囲算出部
11 … システム行列算出部
12 … 再構成部
Li … i番目のLOR
A´ … (交叉範囲を示す)保持用配列
aij … 確率(システム行列中の要素)
νj … ボクセル
HEX … 平行六面体
M … 被検体
Claims (3)
- 被検体内に投与されたポジトロン放射性薬剤から放出される放射線を検出して電気信号を出力する複数の検出器と、前記電気信号に基づいて、2つの前記検出器において放射線が同時観測されたことを検出する同時計数回路と、前記同時計数回路の出力に基づいて、システム行列を算出するシステム行列算出手段と、当該システム行例に基づいて、前記ポジトロンの分布画像を画像として生成する再構成手段とを有するポジトロンCT装置であって、前記同時計数する2つの検出器を結ぶ仮想上の直線である同時計数LORと画素との交叉範囲を求める交叉範囲算出手段を更に有し、前記システム行列算出手段は、前記交叉範囲に含まれる前記システム行列中の要素を演算することによりシステム行列を求めることを特徴とするポジトロンCT装置。
- 請求項1に記載のポジトロンCT装置において、前記画素は3次元のボクセルからなり、前記交叉範囲算出手段は、前記LOR両端にある前記検出器に外接する平行六面体で近似して3次元の前記交叉範囲を求めることを特徴とするポジトロンCT装置。
- 請求項2に記載のポジトロンCT装置において、前記平行六面体を形成する各々の面が長方形あるいは正方形であることを特徴とするポジトロンCT装置。
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US12/863,615 US8546763B2 (en) | 2008-01-22 | 2008-01-22 | Positron computed tomography device |
JP2009550390A JP5152202B2 (ja) | 2008-01-22 | 2008-01-22 | ポジトロンct装置 |
PCT/JP2008/050802 WO2009093305A1 (ja) | 2008-01-22 | 2008-01-22 | ポジトロンct装置 |
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JP2012233881A (ja) * | 2011-04-28 | 2012-11-29 | Toshiba Corp | 核医学イメージング方法、核医学イメージング装置及び記憶媒体 |
WO2012173155A1 (ja) * | 2011-06-14 | 2012-12-20 | 株式会社東芝 | 再構成装置、方法及びプログラム |
WO2013035883A1 (ja) * | 2011-09-09 | 2013-03-14 | 株式会社東芝 | ポジトロン放射断層撮影システム、再構成装置及び距離比決定方法 |
JP2014100574A (ja) * | 2012-11-20 | 2014-06-05 | Inst Nuclear Energy Research Rocaec | 三次元レイトレーシングの投影方法 |
CN111881412A (zh) * | 2020-07-28 | 2020-11-03 | 南京航空航天大学 | 一种基于cuda的pet系统矩阵计算方法 |
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JP4983984B2 (ja) * | 2009-01-30 | 2012-07-25 | 株式会社島津製作所 | 放射線断層撮影装置 |
JP2010178867A (ja) * | 2009-02-05 | 2010-08-19 | Fujifilm Corp | 放射線撮影用ネットワークシステム及び放射線画像撮影システム制御方法 |
JPWO2010109523A1 (ja) * | 2009-03-25 | 2012-09-20 | 株式会社島津製作所 | 放射線断層撮影装置 |
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CN108717716B (zh) * | 2018-04-03 | 2022-05-17 | 江苏赛诺格兰医疗科技有限公司 | 数据校正方法、装置和计算机存储介质 |
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JP2007286020A (ja) * | 2006-04-18 | 2007-11-01 | Inst Nuclear Energy Research Rocaec | 画像再構成方法 |
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US5378893A (en) * | 1993-10-26 | 1995-01-03 | General Electric Company | Radiation event qualifier for positron emission tomography |
JP4650324B2 (ja) * | 2006-03-29 | 2011-03-16 | 株式会社島津製作所 | 核医学診断装置 |
JP5396684B2 (ja) * | 2006-06-14 | 2014-01-22 | 株式会社島津製作所 | 核医学診断装置およびエミッションデータの吸収補正方法 |
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US20100284600A1 (en) | 2010-11-11 |
JP5152202B2 (ja) | 2013-02-27 |
US8546763B2 (en) | 2013-10-01 |
JPWO2009093305A1 (ja) | 2011-05-26 |
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