Source: https://patents.google.com/patent/WO2002004932A1/en
Timestamp: 2018-08-18 05:41:13
Document Index: 2339080

Matched Legal Cases: ['art 1', 'art 2', 'art 3', 'art 1', 'art 4', 'art 5', 'art 7', 'art 8', 'art 1', 'art 8', 'art 9', 'art 1']

WO2002004932A1 - X-ray measuring apparatus - Google Patents
WO2002004932A1
WO2002004932A1 PCT/JP2001/004946 JP0104946W WO0204932A1 WO 2002004932 A1 WO2002004932 A1 WO 2002004932A1 JP 0104946 W JP0104946 W JP 0104946W WO 0204932 A1 WO0204932 A1 WO 0204932A1
PCT/JP2001/004946
A diagnostic X-ray measuring apparatus having a high spatial resolution and a high sensitivity. The X-ray measuring apparatus comprises an X-ray source for emitting X-rays from an X-ray focal point, an X-ray sensor in which a plurality of sensing elements each having a blind part and a sensitive part encompassed by the blind part are two-dimensionally arrayed, data processing means for collecting the output signals of the sensing elements and for data-processing the same, an X-ray grid arranged between the X-ray focal point and the X-ray sensor at a predetermined distance from the X-ray focal point and having X-ray transmissive members and X-ray blocking members arrayed alternately in a first direction. The period of a linear projected image of the X-ray blocking members projected by X-rays on the sensing surface of the X-ray sensor in the first direction is an integral multiple of twice or more of the period of the array of the sensing elements substantially in the first direction, thereby forming an image of a large field of view without any moire.
X-ray measuring device technology field
The present invention is a planar X-ray detector X-ray imaging apparatus capable of capturing high-quality images using, X-ray fluoroscopy apparatus, an X-ray gauge measuring device such as a cone-beam CT system. BACKGROUND
X-ray fluoroscopic apparatus which performs measurement of the X-ray image using a two-dimensional X-ray detector, 及 Pi X-ray imaging devices are known in the art. X-ray source and Konbi beam CT performs rotation photographed while one revolution around Ken查 target two-dimensional X-ray detector, also fixing the X-ray source and a two-dimensional X-ray detector, one rotation inspected there is a cone-beam CT for rotating photographed while (JP-1 0 - 1 9 2 26 7 No.: prior art 1).
In cone-beam CT, by performing each correction process against a plurality of images obtained by rotating the photographing to obtain a set of projection data. The obtained set of projection data, by performing a 3D reconstruction process using the three-dimensional reconstruction algorithm to obtain a three-dimensional image.
3D reconstruction algorithm of the CT is "image Engineering" (Author Shin Hasegawa, Corona, published, pp 1 9 5 - 1 9 9:. Prior art 2) is described in. The three-dimensional reconstruction algorithm cone beam CT, a method such as full Erudokanpu method is used. In particular, One to Feldkamp method Rere Te is, 'P racticalconebeamalgor ithm I (LA F eldka mp ^ J ournal of O ptica 1 S ocietyof Am erica, vol. 1 (6), pp. 6 1 2- 6 1 9, 1 9 8 4: described in the prior art 3).
The two-dimensional X-ray detector used in cone-beam CT, X-ray I mage I ntensifier (hereinafter, abbreviated as XII.) And a television camera combined via an optical system XII- camera type X Senken can (JP-1 0 1 9 2 2 6 7 No.: prior art 1) and, there is a flat X-ray detector and the like.
. A flat X-ray detector, the possibility of the tomography applications, "Trends in Flat Panel Detector" (rice 邑清 Shinya, video information, V o 1. 3 1 (4), pp 1 25 - 1 3 0: it has been described in the prior art 4).
For example, an amorphous silicon photodiode (hereinafter, a -. Where S i PD as abbreviated) and place the pair of the TFT in a square Matricaria box-shaped, planar X-ray detector that combines these pairs and fluorescent plate directly configuration is known. The planar X-ray detector of this type, the fluorescence X-rays are generated by entering the fluorescent plate is converted into electric charges incident on the a- S i PD nearest. Charge is accumulated to be read. In this example, a one S i PD functions as an independent (discrete) detection elements.
As means for reducing the scattered X-rays incident on the two-dimensional X-ray detector, the scattering X-ray shielding grid (hereinafter, simply abbreviated as X-ray grid.) It is. Ri by the placing the X-ray grid in front of the two-dimensional X-ray detector, X-ray fluoroscopy, X-ray imaging, can be reduced scatter in 及 Pi cone-beam CT imaging.
X-ray Dali head has a laminated structure of repeated X-ray shielding material such as an X-ray transmitting material and lead aluminum alternately. There are cross-X-ray Dali head which is integrally arranged perpendicular to each other the two X-ray Dariddo having this stacked structure. That you use the Konbi Ichimu CT imaging on the scattering X-ray shielding X-rays Dali head is known (JP-A 9 one 1 4 9 8 9 5 No.: prior art 5).
Technology bundled addition for adding the output signals of the plurality of detector elements of the two-dimensional X-ray detector in a one-dimensional direction or two-dimensional direction (binning) is known (JP-A 9 one 1 9 70 5 1 No.: conventional technology 6). XII- The force camera X-ray detector, is known to be possible with this to change the number of output pixels of the television camera. This is also known in the cone-beam CT shooting (JP 1 1 one 2 2 6 004 JP: prior art 7).
The bundled addition, to reduce the number of data of the output signal, the effect of shortening the time for outputting images per sheet, the effect of shortening the time required for data processing can be realized. Ichi且, the output signals of the detecting elements after memorize in the memory, performs an addition bundled by post-processing, it is also possible to shorten the time required for arithmetic processing after bundling addition.
Be one times the integral fraction of the period of the array of planar X-ray detector for shielding X-rays projected onto the surface of the detection element 蔽 X-ray Dali head detecting element the period of X-ray-shielding material of the X-ray is known (JP-A-9 - 75 3 3 2 No. Gazette: prior art 8).
Using the shadow of the X-ray shielding material of the X Seng Li head projected on the surface of the detector elements of the planar X-ray detector by the X-ray, a method to align the X-ray source and the X-ray grid known (JP-A-4 one 3 0 8 8 0 9 No.: Supporting coming technology 9).
Further, by using the shadow of the X-ray shielding material of the X-ray grid projected on the surface of the detector elements of the planar X-ray detector by the X-ray, a method to align the X-ray source and detector known and that (JP-A 9 - 6 60 54 No.: prior art 1 0).
First, a description will be given of the terms used in the following description.
(1) Amorphous silicon Konfo Todaiodo: In the following description, a - abbreviated as S i PD.
(2) scattered X-ray shielding grid: In the following description, simply abbreviated as X-ray glycidyl Tsu de.
(3) flat X-ray detector: detection element refers to X-ray detectors arranged in a plane in two dimensions. In the following description, simply referred to X-ray detector.
(4) Detection element: in the example described below, consists of a- S i PD paired with TFT and the fluorescent layer. Detection element, a sensible area a- S i PD varying fluorescence generated by the fluorescent layer into electrical signals are formed (Yukan part) by X-ray, dead region (dead portion other than the sensitive region, including the dead zone portion).
(5) Detection: By the example described below, a surface in which a plurality of a- S i PD in flat X-ray detector is formed.
Using an X-ray detector X-ray fluoroscopic apparatus which performs measurement of X-ray images, X-ray shooting device, for X-ray measurement apparatus for the diagnosis of such a cone-beam CT apparatus, diagnosis Dan'no improved spatial resolution improving been required, miniaturization of the detection elements of the X-ray detector has been developed. Further, the X-ray measuring device for diagnosis, Ri Contact by reduction of X-ray exposure amount in addition to the improvement of the spatial resolution is required, sensitivity of X-ray detection is required.
When using the X-ray detector, there is a problem that has image quality deterioration can be avoided by the scattered X-rays. To reduce the scattered X-rays, to also by the distance of the X-ray shielding material of the X-ray grid so as to correspond to the spacing of the detector elements, as detection element is miniaturized, the interval of the X-ray shielding material is smaller consisting of a lead to desensitization X-ray grid, there is a problem that no to be increased in the X-ray dose to obtain a predetermined sensitivity. Further, when the detection element is miniaturized, the distance between the X-ray shielding material of the X-ray grid so as to correspond to the spacing of the plurality of detection element group, greater than the spacing of the detector elements the distance of the X-ray shielding material it is conceivable to.
However, in either case, there is a problem that moire is caused by correspondence between the period of the sensitivity distribution of the periods and the X-ray detector array of X-ray shielding member is displaced. In particular, since the X-ray detector sensitivity distribution characteristics are steep, easily occurs moire, the cone-beam CT image, say the image quality degradation due to § over Chifata preparative by Moire reduction quantification of 及 Pi CT value occurs a problem there is. For example, as shown in FIG. 6, causing a very complex Achifata bets as a whole with a plurality of curved portions derived from further there ring in addition to the ring arches Fatah bets it is the present inventors - yo Ri confirmed ing. Figure 6 is an example of artifacts which appeared in the center of reconfiguration images of water phantom cylindrical large diameter.
In the X-ray measuring apparatus using an X-ray detector with detector elements of small size, and effectively reduces the scattered X-rays, without a drop in sensitivity, high sensitivity, it is desired to realize a high spatial resolution there. Disclosure of the Invention
An object of the present invention, Ru near to provide an X-ray measurement apparatus for diagnosis which can obtain an image having a large field of view with no moire with high sensitivity at high spatial resolution. ,
X-ray measuring apparatus to which the present invention is applied, the sequence plurality of detecting elements in a two-dimensional with the X-ray source that occur the X-rays from the X-ray focal point, and a sensible portion surrounded insensitive portion and insensitive portion and X-ray detectors, and a data processing means for performing data processing by collecting the output signals of the plurality of detecting elements performs control of photographing, the X-ray focal point between the X-ray focal point and the X-ray detector It is arranged at a predetermined distance relative to the position, and the X-ray transmitting member and the X-ray shielding member is arranged in one direction (first direction) alternately, is fixed in the X-ray transmission flat thin thickness comprising an X-ray Dari' de to shield the scattered radiation.
For example, X-ray detector has a plurality of pairs and a fluorescent layer that is placed in a square Matricaria box shape made of a- S i PD and TFT that functions independently via mutually dead zone (dead portion) (plate) It shall be the known configuration which combined directly. Detector elements, Ru is composed of a pair and a fluorescent layer of a- S i PD and TFT. X-rays that have passed through the test '査 subject after passing through the X-ray grid, is incident on the fluorescent layer. Fluorescence emitted by the fluorescent layer is converted into electric charges incident on the a- S i PD nearest neighbor is stored to the read time of the charge. With no place inspected, the linear projection image of the X-ray shielding member of the X-ray grid by irradiation of X-ray detection surface of the X-ray detector (the surface in which a plurality of a- S i PD is formed) it is possible to get to the top.
In a first configuration of the present invention, the period of one direction of the line-shaped projection images of the X-ray shielding member of the X-ray grid to the detection surface of the X-ray detector, substantially the one direction is 2 or more integer multiples of the period of the array of detection elements, this configuration makes it possible to obtain an image with no moire large field of view with high spatial resolution and high sensitivity.
Further, in the first configuration, the data processing unit performs processing for adding the output signals of the plurality of detector elements adjacent to each other. By adding bundled output signals of the plurality of detection element, a high speed, it is possible to obtain an image without moiré at high spatial resolution 且 one high sensitivity.
In the first configuration, the X-ray grid, X-ray focal point: are fixedly disposed a predetermined distance relative to the position of the X-ray focal point between the X-ray detector, and X-ray focal point in the direction connecting the center of the surface of the X-ray grid or the detection surface of the X-ray detector), the position of the end plane formed of the X-ray incident surface side of the plurality of X-ray shielding member of the X-ray Dariddo a detection surface of the X-ray detector - provided with adjusting means for adjusting the distance between the position (s a surface S i PD is formed), adjusting means, a plurality of X-ray of the X-ray grid the shielding member: in a state where the end portion of the line entrance morphism surface is substantially parallel to retain the detection surface of a plane formed and the X-ray detector can adjust the spacing of the.
X-ray focus position of 及 Pi X-ray Dari' de surface of the X-ray focal point and X-ray Dariddo (:, or the detection surface of the X-ray detector) since the fixed Ru configuration in a direction connecting the center of, for one type of X-ray grid, the spatial resolution, i.e., if the size in one direction of the detection device uses a different X-ray detector also, the X-ray detector in accordance with the spatial resolution select, by adjusting the position by the adjusting means, it is possible to measure the inspection target image.
In the first configuration, the X-ray Dariddo (cross X-ray Dari' de), the first of the first X-ray transmission member and the first X-ray shielding member is arranged in the first direction alternately and X-ray grid, and a second X-ray transmission member and the second X-ray shielding member is alternately composed of the second X-ray Dari' de arranged in a second direction perpendicular to the first direction It is, the first X-ray grid and the second X-ray Dali head is substantially parallel to the central portion of the central portion of the first X-ray Dari' de and second X-ray Dali head There has to be constituted by integrated to substantially match.
Furthermore, the period of the first the first direction of the linear projected onto the detection surface of the X-ray detector of the X-ray shielding member, the test exit surface of the X-ray detector of the second X-ray shielding member period and is substantially equal in the second direction of the projected image of the linear, the first X-ray Dari' de second; X Seng Li head cross X-ray comprised of an X-ray Dariddo the Dari' de. Since having the structure X-ray shielding material of the X-ray Dali head are arranged in two dimensions, less contamination of the scattered X-rays, with high spatial resolution and high sensitivity and c can be obtained with no moiré image in the first configuration, fixed around the test object being placed between the X-ray focal point and the X-ray grid, X-ray source, X-ray grid, and the relative position of the X-ray detector while holding and, X-ray source, X-ray Guritsu .. de, comprising means for rotating the 及 Pi X-ray detector, the data processing means, in a plurality of rotational angle by the rotation, a plurality of detecting elements an output signal in collect, performs data processing for obtaining a tomographic image of Ken查 target.
Radial X-rays from the X-ray focal point by irradiating Ken查 subject performs Konbi beam CT measurement, it is possible to obtain the 3 - dimensional reconstructed image without moire with high spatial resolution and high sensitivity.
In the second configuration of the present invention, similarly to the first configuration, the cycle of the first direction of the linear projected onto the detection surface of the X-ray detector of the X-ray shielding member, the actual qualitatively Ru 2 or more integer multiples der of the period of the array of detector elements in the first direction. By adjusting means having a first configuration and same function, Oite in a first direction, the center of the linear projection image of the X-ray shielding member, the center of the area of ​​the substantially dead zone (not sensitive portion) so as to be positioned, said spacing is adjusted. As in the first configuration, selected for one type of X-ray grid, even when using a plurality of X-ray detectors with different spatial resolution, the X-ray detector in accordance with the spatial resolution to, by adjusting the position by the adjusting means, it is possible to measure the inspection target image.
In a third aspect of the present invention, the first X-ray Dali head cross formed by the second X-ray Dali head described in the first configuration:. X-rays and X-rays Dali head Dali Tsu for use as a de. By adjusting means having a first configuration and same function, in a first direction, the center of the linear projection image of the first X-ray shielding member, the center of the area of ​​the substantially dead zone (dead portion) so as to be positioned, in a second direction, the center of the linear projection image of the second X-ray shielding member, to be in the center of the region of the substantially dead zone (dead portion), said intervals It is adjusted.
Also, the period of the first the first direction of the linear projected onto the detection surface of the X-ray detector of the X-ray shielding member, the substantially second X-ray shielding member X Senken can to the the period in the second direction of the linear projected onto the detection surface of equal configuration. As in the first arrangement, because it uses the X-ray grid having an X-ray shielding 蔽材 sequence of 'are two-dimensionally (cross-X-ray grid), less contamination of the scattered X-rays, high it is possible to obtain a moire-free images with a spatial resolution and high sensitivity.
Incidentally, the prior art 8 previously described, the size of the detector elements does not disclose a small X-ray detector than the distance between the X-ray shielding material. Further, the prior art 9, discloses a method of aligning an X-ray source and the X-ray Dali head, the prior art 1 0 discloses a method of aligning an X-ray source and the detector, the X-ray glycidyl Tsu de and it does not disclose the alignment method of the X-ray detector. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a diagram, Figure 2 showing a structural example of a cone beam CT apparatus of the embodiment of the present invention, examples cone beam CT apparatus in cross-X-ray Dariddo lead foil and the X-ray detector of the present invention cross-sectional view showing an example of a positional relationship between the sensitive region and the dead zone of the detecting element, FIG. 3, adjustment of the positional relationship between the X-ray detector and the X-ray Dali head in Konbi over beam CT apparatus of the embodiment of the present invention sectional view illustrating an example of integer method, FIG. 4, in Konbi chromatography beam CT apparatus of the embodiment of the present invention, be enlarged sectional view of a portion of the X-ray shielding material and the X-ray detector of X 'ray grid a view to explaining shows the positional relationship between the X-ray grid and the detection element, FIG 5 is Oite the cone-beam CT apparatus of the embodiment of the present invention, the detection surface of the X-ray shielding material, each in two directions is arranged the period in the two directions of the projected image, the detection element in the two directions detecting element are respectively formed When adjusted to twice the period, the X-ray shielding material, the sensitive area of ​​the detector element, Ri FIG der illustrating the relative positional relationship of the dead zone, the projection of the X-ray shielding member on the detection surface partially enlarged projection drawing, FIG. 6 is a view to view the Achifata bets by moire in conventional cone-beam CT image. - BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.
Figure i is a diagram showing a configuration example of a cone beam c tau apparatus of the embodiment of the present invention. Cone-beam CT apparatus irradiates X-rays to the inspection target 1
X-ray tube 2, the inspection target 1 rotating device 4 for rotating the holder 3 and the supporter 3 for holding, the X-ray detector 5 for detecting the X-rays transmitted through the inspection object 1, an X-ray grid for shielding scattered rays 6, and controls the adjusting device 7, the X-ray tube 2 and the rotary device 4 and the X-ray detector 5 to adjust by changing the relative position of the X Senken can 5 with respect to the X-ray grid 6, the X-ray detector 5 data collecting device 8 for collecting the output signals of the detecting elements of the data, the data processing device 9 for performing arithmetic processing of the collected data, collected data, and a display device for displaying the calculation processed results 1 consisting of 0, and the like. The function of the data processing device 9 may be provided to the data acquisition device 8.
A 对 and X-ray tube 2 of the X-ray Dali head 6 and the X-ray detector 5 is rotated around the inspection target 1, to perform cone beam CT measurement. Further, by fixing the pair and the X-ray tube 2 of the X Seng Li each time 6 and the X-ray detector 5, by rotating the test object 1 by the rotation device 4 may perform cone beam CT measurement. X-ray detector is composed of a plurality of detection Yunitto to be joined to each other. Each detection unit converts Yuni' bets turned into an electric signal by the fluorescence generated a- S i PD the X-rays incident on the detection unit from the fluorescent layer and the phosphor layer for converting the visible light, TF T from the conversion Yuni' DOO amplifier for amplifying a signal Desa read, the signal output unit for sending a signal amplified by the amplifier unit, the detection Interview - composed of read control section or the like that controls the reading of signals in Tsu and.
Each detection unit in the detection element to TMG, one side has a positive square shape of 0. 1 2 7 mm, Ru are squarely arranged at a pitch 0. 1 2 7 mm in two directions. The sensitive area of ​​the detection element (Yukan portion) has a square shape one side is 0. 1 06 mm. The sensible area in four directions, 0.0 1 0 5 (= 0.0 2 1/2) with a width of mm that have been surrounded by a dead region (dead portion). That is, the width of the dead portion formed between the sensitive region of the adjacent detector element is 0. 0 2 1 mm.
X-ray detector is a square array with a pitch 0. 1 2 7 mm in two directions, consists 3 0 7 2 X 30 7 2 = 943 7 1 84 pieces of detector elements, X-ray detector 1 sides with about 3 9 0 mm size of the square shape.
As X-ray grid, using a first, cross the X-ray grid which is integrally overlapped second X-ray Dali head with the same structure. Each of the first and second X-ray grid, as an X-ray shielding material, is 0. 0 5 0 mm thickness, height 1. 0 1 6 mm, elongated is of approximately 3 9 0 mm length lead foil the use, as an X-ray transmitting material, a thickness of about 0. 2 Omm, height 1. 0 1 6 mm, a length to use elongated secondary aluminum © beam foil about 3 9 0 mm. The 1, X-ray grids ratio of the second X-ray Dariddo is 8: 1. First, second X-ray grid is to match the center of the X-ray Dali head, the first X-ray Dali head arranged in the X-ray incident side of the cross-X-ray Dariddo, lead foil, a surface connecting the end face of the X-ray incident side of the 及 Pi aluminum foil, a second X-ray grid arranged in the X-ray emitting side of the cross X-ray Dariddo. lead foil, 及 Pi aluminum foil and a surface connecting the end face of the X-ray incidence side while maintained substantially parallel to the longitudinal direction of the lead foil in the center of the X-ray Dali head is integrally bonded to be orthogonal.
That is, the longitudinal direction of the lead foil in the center of the first X-ray grid arranged parallel to the first direction, the longitudinal direction of the lead foil in the center of the second X-ray Dari' de, the arranged in parallel in a second direction perpendicular to the first direction, and integrating bonded first 1 X-ray glycidyl Tsu de of and a second X-ray grid. The first X-ray grid, lead foil, the distance between the center and the X-ray focal plane connecting the end surfaces of the X-ray incident side of the 及 Pi aluminum foil is 1. 2 m. In cone-beam CT apparatus of the embodiment of the present invention, the first X-ray grid, lead foil, and a surface connecting the end face of the X-ray incident side of the aluminum foil, the detection surface of the detection element of the X-ray detector (s sensible regions, i.e., the distance between the surface) of formed by a plurality of a- S i PD, a 1 9 mm.
In the direction connecting the center and the X-ray focal point of the surface connecting the end face of the X-ray incident side of the first X-ray Dariddo, face a detection surface of the X-ray detector connecting the end face of the X-ray incident side of the substantially moved parallel to the position of the detection surface of the X-ray detector relative cross X-ray Dari' de, adjusted as follows.
Period in the first direction of the linear projected onto the detection surface of the X-ray detector of lead foil of the first X-ray Dali head by X-rays, substantially, detected in the first direction period of to be twice the period of the array of elements, and in a second direction of the linear projected onto the detection surface of the X-ray detector of lead foil of the second X-ray grid by X-ray but essentially, it is adjusted to be twice the period of the array of detector elements in the second direction. Further, in the first direction, the center of the linear projection image of the lead foil of the first X-ray grid is to be in the center of the width of the substantially dead zone, in the second direction, the center of the linear projection image of the second X Seng Li head lead foil, to be in the center of the width of the substantially dead zone, the end face of the X-ray incident side of the first X-ray Dariddo a surface connecting the interval between the detection surface of the detection element of the X-ray detector is adjusted. Figure 2 is an embodiment of a cone-beam CT origin parallel to the X z plane showing an example of a positional relationship between the sensitive region and the dead zone of the sensing element lead foil cross X-ray Dariddo and X-ray detector in the apparatus of the present invention it is a cross-sectional view through the O (2 1). Origin O (2 1) and orthogonal coordinate system (x, y, z) and y-axis of the rotation center axis of the rotary device 4, or pairs and X-rays of the X-ray grid 6 and the X-ray detector 5 a rotation axis when rotating the tube 2 around the test object 1, the xy plane, the first, second X-ray grid 2 2, 2 3 by configured cross the X-ray grid 6 surface connecting the end face of one of the X-ray Dari' de 2 2 X-ray incident side, the detection surface of the sensing element 及 Pi X-ray detector 2 4 (a sensitive area) taken parallel to 2 7. The Z-axis, the direction connecting the center of the surface connecting the end face of the X-ray of the X-ray tube 2 focus F (2 0) and the first X-ray Dali head 2 2 X-ray incident side.
2, through the center of the lead foil 2 6 arranged in a first X direction of the X-ray grid 2 2, X-ray path 2 9 leading to the center of the width of the dead band 2 8 formed in the X direction , and through § lumi two © arm foil 2 5 arranged in the first X-direction of the X-ray grid · 2 2, X-ray path 3 0 leading to center of the width of the dead band 2 8 formed in the X direction It is shown. In Figure 2, the structure of the second X-ray grid 2 3 are omitted.
Shown in Figure 2: X-ray detector 2 4, 2 4 'each, X-direction, and has a size of the same detector element in the y-direction, the dead band 2 8, 2 8 the same width' but with, X-rays detector 2 4 ', rather than the X-ray detector 2 4, spatial resolution is poor, a sensitive area 2 7, the area of ​​the larger area of ​​the sensitive area 2 7 (i.e., the X-ray detector 2 4, the size of the detection element is larger than the size of the detection elements of the X-ray detector 2 4.).
In FIG. 2, to cross the X-ray grid 6, X-ray detector 2 4, 2 4 'in the X direction, 及 Pi y directions, respectively, by the dimension of 1 Z 2 Sa I's of the detection element Schiff good record, be placed in door.
Further, in the example shown in FIG. 2, the first having the same structure, a description has been given of an example of using cross X-ray Dari' de that combines overlapping the second X-ray grid, cross shown in FIG. 2 instead of the X-ray grid, the first X-ray grid for lead foil in the X direction are arranged, it may be used either in the second X-ray grid for lead foil in the y direction are arranged even in this case, the method described above, in the manner described below, may be performed relative alignment of the X-ray grid and an X-ray detector.
X-ray detector 2 4, or, the detection surface of the two 4 ', the first X-ray grid
It is moved while maintaining a parallel to the end faces of the two second X-ray incident side, to adjust the position of the detection surface of the X-ray detector for cross- X-ray Dariddo by. Thing, one of the first the X-ray Dali head 2 2, can be used a plurality of X-ray detectors with different spatial resolutions.
Figure 3 is a cross-sectional view illustrating an example of a method for adjusting the positional relationship between the X Senken out unit and the X-ray Dariddo in cone-beam CT apparatus of the embodiment of the present invention. X-ray detector 5 and the X-ray grid 6, respectively, are fixed to the frame 4 0 Sly was installed in the sul slide plate 4 1. X Senken can 5 and the X-ray glycidyl each time 6 is mounted perpendicular to the frame 4 0.
Distance adjusting adjusting screw 4 2 screw holes 4 3 for are formed on the X-ray grid 6, is screwed to the adjusting screw 4 2 threaded holes 4 3. Adjusting screw 4 2 is screwed toward the X-ray detector 5. The adjusting screw 4 portions 2 of the head contact on the X-ray detector 5, Ri by the adjustment screw 4 2 heads X-ray detector 5 is not so receiving plate 4 4 ​​corruption is provided. By extruding the side of the X-ray detector 5 by turning the adjusting screw 4 2, parallel to enlarge the distance between the X-ray Dariddo 6 and the X-ray detector 5. By pulling on the side of the X-ray grid 6 by turning the Flip sleep regulation 4 2, it is possible to narrow the distance between the X Seng Li each time 6 and the X-ray detector 5. The shown to Example 3, but the adjusting screw has only one further by increasing the number of adjustment screws, it is possible to improve the accuracy of adjustment of the distance.
The first center portion of the surface connecting the end face of the X-ray glyceraldehyde each time 2 2 X-ray incident side of the position of a predetermined distance from the X-ray tube 2 X-ray focal point F (2 0) of the X-ray grid 6 to come to move the slide plate 4 1 to the X-ray grid 6 is fixed, to secure the slide plate 4 1 to the frame 4 0. Extruding the adjusting screw 4 2 on the side of the X-ray detector 5, or to pull out the side of the X-ray grid 6. The plane adjustment screw 4 2 heads of the X-ray detector 5 to Bukkaru position, X-rays detector 5 moves the slide plate 4 1 fixed. Fixing the slide plate 4 1 to the frame 4 0. While not placing an inspection object, measure the projected image of the X-ray shielding material of the X-ray detector 5 occurred the X-ray (lead foil 2 6).
X direction in the projected image, and heart position in the linear projection image of 及 Pi y-direction of lead foil, and detects the center position of the dead zone width in the X direction, and the y-direction, the lead foil in the X direction period of the center position of the projected image of the linear is substantially as twice the period of the array of detector elements in the X direction, linear projected image of the lead foil by y direction the period of the center position, substantially as twice the period of the array of detector elements in the y-direction, further, the linear projection images in the X direction of the lead foil of the first X-ray grid center, so as to be located substantially in the center of the dead zone width in the X direction, linear center of the projected image of the V direction of lead foil of the second X-ray grid, substantially in the y-direction deadband to be in the center of the width of, the X-ray detector 5 is to move the slide plate 4 1 fixed, to adjust the distance between the X-ray Dariddo 6 and the X-ray detector 5. In addition, to confirm whether or not the moire is visible in the projected image. Moire until no longer visible, to adjust the distance.
Bundled by a cone beam C Ding apparatus of the embodiment of the present invention, for adding the output signals of the plurality of detection elements of the X-ray detector, one direction of the X or y direction, or in two directions X and y directions to perform the addition (binning).
Cone-beam CT apparatus of the embodiment of the present invention performs a bundle addition
With two modes. First bundled addition mode is required compared to a long processing time in the second bundling addition mode, a high resolution mode which can provide images of high spatial resolution. Second bundling addition mode, although spatial resolution compared to images obtained in the first bundling addition mode poor, it is possible the second arithmetic processing faster than bundled addition mode is. Standard counting it is a standard mode that gives the conditions.
In high-resolution mode, X-direction, respectively performs a bundled addition for adding the outputs of the two detector elements in 及 Pi y-direction, which adds the outputs of the total of four detection element. In the standard mode, X-direction, respectively Te 及 Pi y direction odor performs bundling addition for adding the outputs of the four detection elements, adds the outputs of the detector elements of a total 1 6. The ratio of the spatial resolution in the spatial resolution and the standard mode in the high resolution mode is 1: 2.
The number of bundled summing detecting elements (number of bundled summing element), i.e., the number of outputs of the detector elements to be added may be variously changed. Collecting data at, after executing the control for adding the output of the detection element, when collecting the addition result, degree of increasing the number of bundled summing element, data can be collected at high speed.
Number bundled summing element in the x-direction and bundled adding the number of elements in the y-direction ^ may be a not rather equal configuration, for example, to reduce the lowering of sensitivity without increasing the number of bundled summing element in the X-direction, y by increasing the number of bundled summing element in the direction, achieving high speed, it is possible to perform high sensitivity and high-speed data acquisition.
4, the cone-beam CT apparatus of the embodiment of the present invention, enlarged cross-sectional view through the origin parallel to the part of the X z plane of the X-ray shielding material and the X-ray detector of the X-ray grid O (2 1) and is a diagram for explaining the positional relationship between the X-ray grid and the detection element. '
4, there is an X-ray focal point F of the X-ray tube to the left of the z-direction (not shown) (2 0) in FIG. 4. Dotted 42 1, 42 2, 42 3, 424, 4 2 5 4 2 6 X-ray of the X-ray grid are emitted from the X-ray focal point, shielding material enters the advanced detection element in contact with the (lead foil) It shows the X-ray path to. Each dotted line 4 2 1-42 6 are not parallel to each other, the path of the X-ray indicated by the dashed line 4 21-4 26, as shown in exaggerated in Figure 2, X-rays emanating from the X-ray focal point it is a path by the beam.
First X-ray glyceraldehyde each time 22 cross the X-ray glycidyl each time 6, the X-ray shielding material to array in the X direction (lead foil) 40 1, 40 and 2, 403, X-ray transmitting material that array in the x-direction consists (Arumiyuumu foil) 4 1 1, 41 2, 4 1 3, 4 1 4, at the end face of the first X-ray Guritsu de 2 2 X-ray incident side lead foil, the end face of 及 Pi aluminum foil lead foil at the end face of the plane formed 4 71, X-ray emitting side, and forming surface 47 2 of the end face of the aluminum foil which respectively lies in the same plane parallel to the X y plane (first, not shown in FIG. 4 the same is true of the X-ray grid 2 3).
In Figure 4, the sensitive area 4 5 1 of the four detection elements of the X-ray detector 24, 4 5 2, 4 5 3, 4 5 4 illustrates a. X-ray shielding material of the X-ray grid, 及 Pi X-ray transmitting material by X-rays emitted from the X-ray focal point F (20), and it slightly is enlarged to detect surface 4 6 1 of the X-ray detector 24 It is projected. The magnification, the distance between the distance between the detection surface 46 1 and X-ray focal point F (2 0), X-ray focal point F (20) and the surface 4 7 1 of the X-ray grid which is the ratio. The distance between the front 4 7 3 of the X-ray grid surface 4 7 1 and the X-ray detector and L (47 0).
Hereinafter, the position of the X-ray Dariddo projected onto the detection surface 461, the positional relationship of the sensitive area of ​​the detection element will be described. Example shown in FIG. 4, the period the period of the image of the first X-ray shielding material of the X-ray Dari' de projected onto the detection surface 4 6 1 by X-ray from the X-ray focus, the detection element is formed It doubled so as showing a case where it is adjusted.
Dotted 8 0 1, 8 0 2 8 0 3 indicates the boundary of the detecting element group bundling adding the output in the high resolution mode is added is made, the position of these boundaries, the sensitive detection elements corresponding to heart position within the width of the dead zone is formed between the regions.
Bundled addition is, X direction in the high resolution mode, and the total for the four detector elements of their respective two detector elements in the y-direction, the sum of each of the four detection elements X direction in standard mode, and in the y direction 1 6 It is performed for the detection element. That is, in the high resolution mode, the period of the image of the X-ray shielding material projected onto the test exit face consists period of the array of detection element element group to be bundled adds the same. Period of the array of detecting element groups to be added bundled in standard mode, an integral multiple of the period of the array of detecting element groups to be added bundled with high resolution mode.
Border 8 0 1, 8 0 2 8 0 3 corresponds to the center position of the width of the dead zone is formed in the x-direction, X-ray shielding material arranged in the projected X-direction on the detection surface 4 6 1 of to match the center position of the image, the first X-ray Dali Tsu distance between positions 4 7 1 of the front surface of the de of the front 4 7 3 of the X-ray detector L (4 70) is modified adjusted It is. Distance changing of L (4 70) is performed by adjusting to change the position of the front 4 7 3 of the X-ray detector.
As a result, since the period of the image of the X-ray shielding material projected on the detection surface, and the period of the array of detecting element groups to be bundled the summing is that Itasu over, thereby preventing occurrence of moire. Moreover, the sensitive area of ​​the detector elements so effectively reduce the rate that will be shielded by the X-ray shielding material, the sensitivity of the X-ray measuring apparatus is improved. Furthermore, the addition bundled in the X direction, 及 Pi y direction (For example, in the X direction, lead foil 4 0 1 and lead foil pair 402) to the same X-ray shielding material for the inner detector element child group since executed, it is possible to suppress the deterioration of spatial resolution due to the addition of the output of the detecting element group to a minimum.
Figure 5 is the cone beam CT apparatus of the embodiment of the present invention, X Direction, and the y-direction in the X direction of the center position of the image projected on the detection surface 46 1 of the X-ray shielding material arranged respectively, and the period in y-direction, X direction detecting element are respectively formed, when adjusted to twice the period of the detection elements in 及 Pi y-direction, X-rays shielding material, the sensitive detection elements region is a diagram illustrating the relative positional relationship between the dead zone, a partial enlarged projection view obtained by projecting the X-ray shielding member on the detection surface 46 1, in the projection view of the FIG. 4 from the vertical ones toward the paper is there. In the example shown in FIG. 5, FIG. 2, as in FIG. 4, first with the same structure and a cross-X-ray Dariddo constituted by the second X-ray grid.
X direction, and detection elements respectively are formed in the same regular intervals in the y direction (0. 1 2 7 mm X 0. 1 2 7 mm) sensible region of (0. 1 0 6 mm X 0. 1 06 mm) 1 0 1, 1 0 2, 1 0 3 1 04, 1 1 1, 1 1 2, 1 1 3, 1 1 4, 1 2 1, 1 2 2 1 2 3, 1 24, 1 3 1, around 1 3 2, 1 3 3 1 34 is surrounded by the dead zone (width 0. 02 1 mm). Region near or et width 0. 0 1 5 mm of each the sensitive areas in the vicinity of two adjacent sides of each the sensitive region is projected to the cross X-ray grid is covered by a de (detection surface 46 1 the dimensions of the X-ray shielding material is 0. 0 5 1 mm).
The X-ray shielding material projected on the detection surface 46 1, hole by projection onto the detection surface 4 6 1 of the X-ray shielding material of the cross-X-ray grid, by the projection of the X-ray shielding material on the detection surface 46 1 5 0 1, 5 0 2, 5 0 3, 5 04 are formed. First, when using the cross-X-ray grid constituted by 及 Pi second X-ray grid, holes 50 1, 5 0 2, 5 03, the 504 parts of the, X-ray of the first X-ray grid shielding material, any of the second X-ray shielding material of the X-ray grid is a portion not projected.
Dotted lines shown in FIG. 5 shows the X-direction, the range boundaries of the detection element element group to be added bundled by 及 Pi y direction. In the example shown in FIG. 5, bundled summation, X direction is performed in 及 Pi y direction relative to a total of four elements of each of the two elements. The center of the area where four detection elements which are bundled addition is occupied, so that the center of the hole is that Itasu over, X direction of the projection image onto the detection surface of the X-ray shielding material of the cross-X-ray Dari' de, and the center position in the y-direction, so as to match the center position of the width of the dead zone, for the front of the position of the first X-ray grid cross X-ray Dali head, the position of the detection surface of the X-ray detector adjust. That is, as shown in FIG. 5, the position of the dotted line indicating the bounds of the detection device group to be added bundled in the X direction, 及 Pi y-mind position within the width of the dead zone, 及 Pi, cross the X-ray X direction of the projection image onto the detection surface of the X-ray shielding material of the grid is made to coincide with the center position in 及 Pi y direction.
As a result, the period of the image of the X-ray shielding material of the cross-X-ray grid projected on the detection surface, bundled summed by Itasu period and is over a sequence of the detector element group Runode, occurrence of moire can be prevented . Also, it is the sensitive region of the detection element
Since the ratio is shielded by the X-ray shielding material can be effectively reduced, the sensitivity of the X-ray measuring equipment is improved. Moreover, X-direction, detection device group to be added bundled by 及 Pi y-direction is in the interior of the pores, the same pair of X-ray shielding material (for example, in X direction, lead foil 4 0 1 and lead foil 4 0 since addition entangle detecting element group inside the second pair) is performed, Ru can suppress a decrease in spatial resolution due to the summing of the output of the detection element group X direction, and a minimum in the y-direction.
In the standard mode, X-direction, and it is added bundled with detecting elements a total of 1 6 of the four detection element in each y direction. As a result, it is possible to prevent the cycle of the image of the X-ray shielding material projected on the detection surface cross X-ray grid, since the period of the sequence of the detector element group to be bundled addition is that Itasu over, the occurrence of moire. Since the sensitive area of ​​the detection element can effectively reduce the rate is shielded by the X-ray shielding material, the sensitivity of the X-ray measuring apparatus is improved.
Furthermore, the addition bundled in the X direction, 及 Pi y direction, the same pair of X-ray shielding material (e.g., in the X direction, lead foil 4 0 1 and the lead foil 4 0 2 pairs) inner detection element group since executed for, it is possible to suppress the deterioration of spatial resolution due to the addition of the output of the detecting element group to a minimum. In the standard mode, 1 by 6 bundled addition of detection elements, the spatial resolution is reduced, the effect of. The amount of data processing to be performed on or after the bundling addition is shortened greatly reduced computation time.
In cone-beam CT apparatus of the embodiment of the present invention, bundling addition it is performed in two stages. The bundled addition, prior to storing the signal to collect the memory from the detection elements, configurations and carried out by hardware, both configurations performed after memorize in the memory in software are possible, these two configurations series is not available in. Bundled addition of x-direction, and a total of four detection elements of the two detector elements in the y direction, prior to storing the signals from the detecting elements in the memory and executed by Haiti Douea. The resulting bundled summed signal (4 element bundle ne addition signal) is stored in a memory is collected. In the post-process, bundles addition of the collected four bundled summed signal (4 elements bundled addition signal) is performed by software. -
That is, to perform the bundling addition of the detection device 1 6 in combination with a post-treatment with pretreatment and software by hard ware. Function by hardware capable of executing bundled addition of four detection elements using X-ray detector having a (4 elements bundled addition function), by software post-processing, can perform bundling addition of the detection element 1 6. As a result, the to generalize the design of the X-ray detector to allow cost reduction, based on the relationship of the computation time and space between resolution, the flexibility of how the use of X-ray measuring device that high Mel it can.
When using a cross-X-ray grid as one detection element to one hole of the corresponding, as in the example shown in FIG. 5, four detection for one hole of the element than when using cross X-ray Dali head to correspond, there is effect that shielding capacity of the scattered radiation is high. At this time, when not executing the bundled addition, the X direction of the projection image onto the detection surface of the X-ray shielding material of the X-ray grid, the center position location in 及 Pi y-direction, the boundary line of detector elements, i.e., X direction, the X direction of the dead zone width in 及 Pi y-direction, and coincides with the center position in the y-direction. As a result, Runode can reduce the rate of the sensitive area of ​​the detection element is shielded by the X-ray shielding material effectively, the sensitivity of the X-ray measuring apparatus is improved. Also, it can deter the occurrence of moire. Industrial Applicability
X-ray measuring apparatus of the present invention, applied X-ray detector X-ray imaging apparatus capable of shooting of high-quality images using, X-ray fluoroscopy apparatus, a device for diagnostic purposes such as cone beam CT device It is, according to the X-ray measuring apparatus of the present invention, the following effects.
(1) the sensitive area of ​​the detector element effectively reduces the rate of play shielded by the X-ray shielding material, it can prevent the occurrence of moire can be improved detection sensitivity of the X-ray.
(2) bundled since the addition performed by the addition of the output signals of the detection elements in the inner region of the pair of X-ray shielding material can be suppressed to minimize the degradation of the spatial resolution in the bundled addition.
(3) by bundling the addition of the output of the detecting element can be fast to obtain an image without moiré at high spatial resolution 且 one high sensitivity.
(4) by adjusting the spacing of the X-ray grid and an X-ray detector, relative to the period of the detection elements is different X-ray detector, flexibility of the X-ray grid can be used with the same X-ray Dali head it can be increased.
(6) As the X-ray grid, X-direction, and cross the X-ray grid Ru structure identical der of 及 Pi y-direction, the sequence interval is X-direction of the detection element is the same in both directions 及 Pi y Direction X using a line detector, X-direction, and the y direction can achieve the same spatial resolution in both the direction. '
1. The X-ray source which irradiates the X-ray focal point to the test object X-ray, a plurality of detector elements and a insensitive portion surrounding the sensible portion and the sensible portions arranged in a two-dimensional, transmitted through said object a flat X-ray detector for detecting and t X-ray image, and a data processing means for performing data processing relating to the X-ray image by collecting the output signal of the detection element, the plane type X-ray and the X-ray focal point are arranged at a predetermined distance relative to the position of the X-ray focal point there between the detector, X-rays transmitting member and the X-ray shield member and the first direction are arranged X-ray grid alternately It has the door, and the period in the first direction of the projected image of the detection surface of the flat X-ray detector of the X-ray shielding member by the X-ray is substantially the first X-ray measurement instrumentation, characterized by being configured to be a two or more integral multiple of the period of arrangement of the detection element in the direction
2. The data processing means, X-rays measurement device of the plurality of the first term range billed, characterized in that the output signal is configured to perform a processing of adding the detecting device, wherein adjacent to each other. ,
3. The distance between the position of said planar X-ray detector of the X-ray Dali head in the direction connecting the center of the X-ray focal point and the X-ray Dali head. Of the X-ray Dali head surface and the planar X-ray detector of the detection surface and the X-ray measuring apparatus according to the range set forth in claim 1, wherein characterized in that it comprises adjustment means for adjusting while maintaining the relationship.
4. The X-ray grid, first the X-ray grid in which the first X-ray transmission member and the first X-ray shielding member is arranged in the first direction alternately, the second X alternately the line transmission member and the second X-ray shielding member, and a second X-ray Dali head arranged in a second direction perpendicular to said first direction. and the first X-ray Dali head and said second X-ray Dali head and the X-ray measuring apparatus substantially parallel to disposed claims, characterized by comprising first claim of.
5. The period in the first direction of the projected image to the detection surface of the first X-ray shielding member, before 5 Symbol projected image to the detection surface of the second X-ray shielding member X-ray measuring apparatus claims paragraph 4, wherein the the period in the second direction and substantially equal.
6.. Around said object disposed between said X-ray focal point and the X-ray Dariddo, the X-ray source, the X-ray grid, relative of 及 Pi the plane type X-ray detector while maintaining the Do position, comprising means for providing a 0 relative rotation with respect to the detection target, the data processing means collects the output signal of said detecting elements at a plurality of rotational angle by the rotation Te, X-rays measurement device ranging first claim of claim, wherein the performing data processing for obtaining a tomographic image of said object.
7. The X-ray source which irradiates the X-ray focal point to the test object X-ray, a plurality of detector elements and a insensitive portion surrounding the sensible portion and said 5 sensible portions arranged in a two-dimensional, the test object a flat X-ray detector for detecting transmitted X-ray image, and a data processing means for performing data processing relating to the X-ray image by collecting the output signal of the detection element, the plane type X-ray and the X-ray focal point test • is arranged at a predetermined distance relative to the position of the X-ray focal point between the output device, and 0 X-ray transmission member and the X-ray grid in which an X-ray shielding member is arranged in the first direction alternately the in better direction of the X-ray focal point and connecting the central part of the X-ray Dali head, the distance between the position of the plane type X-ray detector and the position of the X-ray Dariddo, the X-ray grid and an adjusting means for adjusting while maintaining the relationship between the test exit surface of the surface with the planar X-ray detector, and 5 wherein Period in the first direction of the linear projection image to the detection surface of the X-ray shielding member, two or more integral multiple of periodic array of the detector elements in substantially the first direction X-ray measurements, characterized by being configured such that the
8. The by adjusting means, the center of the line-shaped projection images of the X-ray shielding member in the first direction, so as to be positioned substantially in the center of the region of the dead part, the distance is adjusted X-ray measuring apparatus billed ranging paragraph 7, wherein the formed by.
9. The X-ray source which irradiates the X-ray focal point to the test object X-ray, a plurality of detector elements and a insensitive portion surrounding the sensible portion and the sensible portions arranged in a two-dimensional, transmitted through said object It was a flat X-ray detector for detecting X-ray image, and a data processing means for performing data processing relating to the X-ray image output signals collected by the said detection device, a first X-ray transmission member and the first first X-ray grid in which an X-ray shielding member is arranged in the first direction alternately 及 Pi second X-ray transmission member and the second X-ray shielding member is alternately the first direction the second comprises a second X-ray grid, which is arranged in a direction, the first X-ray grid and the second X-ray grid is substantive parallel to perpendicular to the is disposed, and X-ray Dali head disposed a predetermined distance relative to the position of the X-ray focal point between the flat X-ray detector and the X-ray focus, the X Keru you in a direction connecting the center of focus and the X-ray grid, the distance between the position of the plane type X-ray detector and the position of the X-ray grid, the surface of the X-ray grid and an adjustment means for adjusting substantially held parallel to the detection surface of the flat X-ray detector, and a linear to the detection surface of the by the X-ray first X-ray shielding member period in the first direction of the projected image is a two or more integral multiple of the period of the array of detection elements in substantially the first direction, said by the X-ray second X-ray period in the second direction of the linear projection image to the detection surface of the shielding member is located in two or more integral multiple of periodic array of the detector elements in substantially the second direction , by the adjusting means, and have contact to the first direction, the center of the line-shaped projection images of the first X-ray shielding member in a substantially region before Symbol insensitive portion So as to be located, in the first-second direction, so that the center of the line-shaped projection images of the second X-ray shielding member is located at the center of the region of substantially the dead portion, the distance is adjusted X-ray measuring apparatus characterized by comprising been.
1 0. The line to the said detection surface of the first and the period in the first direction of the line-shaped projection images to the detection surface of the X-ray shielding member, the second X-ray shielding member X-ray measuring apparatus and the period in the second direction shaped for projected image substantially claims paragraph 9, wherein the equal correct it and said.
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