KR20220137712A - Radiation detection apparatus and radiation inspection system equipped with the apparatus - Google Patents

Abstract

The radiation detection device 22 includes, for example, a module having a pixel array in which pixels for detecting radiation such as X-rays are arranged in two dimensions in a first direction (Y) and a second direction (Z) that are orthogonal to each other. A plurality of elongated detectors 31 having module columns 132M disposed adjacent to each other through gaps having a predetermined width are provided in a first direction. In the elongated detector, the module column has a long side along the first direction (Y) and a short side along the second direction (Z), and the long side is longer than the short side, and has an elongated spherical shape. is formed The elongated detector is supported in a posture in which the second direction is directed to the scan direction SD and the first direction is directed to a direction orthogonal to the scan direction, and the oblique direction (θ) is formed with respect to the scan direction. MD) to be movably supported. The elongation detector is preferably a plurality of elongate detectors arranged discretely in the scan direction, for example. Upon detection of data irradiated with radiation, the elongate detector is moved in an oblique direction according to a scan command.

Description

Radiation detection apparatus and radiation inspection system equipped with the apparatus

The present invention relates to a radiation detection apparatus for detecting radiation such as X-rays as an electrical signal, and a radiation inspection system equipped with the apparatus, in particular, a module having a plurality of pixels for detecting radiation in a plurality of directions in one direction. The present invention relates to a radiation detection apparatus for detecting the radiation while scanning radiation detectors arranged adjacent to each other and having an elongated shape in plan view, and to a radiation inspection system equipped with the apparatus.

BACKGROUND ART Conventionally, various detection systems are known for radiation detectors that detect X-rays or gamma rays.

When this detector is classified by shape, there are two-dimensional detectors and line detectors depending on whether the radiation detection elements are arranged in two dimensions or in one dimension. Even if the detection elements are arranged one-dimensionally, in reality, the detection pixels are not arranged one-dimensionally one by one, but the detection pixels are arranged in two dimensions vertically and horizontally, and the number of pixels arranged along one axis The number of pixels (at least one pixel) arranged along the other axis is reduced. For this reason, when the detector is viewed in a planar view, it becomes a elongated spherical shape and becomes a line shape or a linear shape. , a linear detector, etc.

As an example of this line detector, the structure described in patent document 1 is known. The detection apparatus described in this patent document 1 is an example of the apparatus (CT apparatus) which performs computed tomography, The radiation detector equipped with the several line detector which opened toward the radiation path radiated from a radiation source. is equipped with

On the other hand, in recent years, in line detectors used in medical modality and non-destructive X-ray inspection apparatuses, so-called direct conversion detectors that directly convert radiation (X-rays, etc.) into electrical signals, or once converted radiation into optical signals And, a so-called indirect conversion type detector that converts the optical signal into an electrical signal is progressing and improving.

In either of these direct conversion types and indirect conversion types, when a structure in which a detection pixel is formed in a semiconductor layer such as silicon is employed as a circuit for sensing X-rays or light, the semiconductor layer is formed of a crystal ingot. needs to be grown, molded, and processed. For this reason, it is difficult in terms of product yield and cost to form a large detection area, ie, a so-called two-dimensional detector in which a plurality of detection pixels are two-dimensionally mapped.

For this reason, in normal product-level manufacturing, for example, a spherical array structure (eg, a spherical array structure in which 40×40 detection pixels (unit pixels for sensing X-rays or light) are arranged two-dimensionally) For example, a module with a size of 8 mm x 8 mm) is created. A plurality of these modules are prepared, and they are closely adjacent to each other in two dimensions vertically and horizontally to constitute a two-dimensional detector, and densely adjacent to each other in one direction to constitute a line detector, which can also be referred to as a one-dimensional detector.

When a plurality of modules are densely adjoined in this way, it is necessary to provide gaps (gaps and voids) of a certain width between modules in order to improve assembly precision, secure wiring space, and the like. The width of this gap is usually set to about 0.5 to 2 times the width of one detection pixel in many cases.

Of course, providing this gap means that there is no detection pixel in the gap portion, and may also be an artifact of the reconstructed image. For this reason, when reconstructing X-ray transmission data (frame data) collected by a modular two-dimensional detector or a line detector, correction to compensate for the lack of collected data due to the absence of detection pixels in these gaps is performed. need to be carried out

Especially when using a line detector, such a correction is essential. When radiation data is collected by scanning using a line detector, that is, a detector in which at least the detection area has an elongated spherical shape in plan view, the orthogonal posture is maintained in the scanning direction orthogonal to the longitudinal direction of the detector. This is because it is common to move (scan) the detector while it remains. In this case, since the longitudinal direction (direction orthogonal to the width direction) of the gap between modules is parallel to the scan direction, the movement of the line detector only moves the gap portion that does not detect radiation as it is in the scan direction.

Therefore, in order to eliminate the disadvantage accompanying presence of a gap, the countermeasure described in patent documents 2, 3, and 4 is known. Among these patent documents, according to patent document 2,

i) A so-called " an example of 'detector tilt arrangement', and

ii) The line detector itself is arranged in the longitudinal direction, but an example of so-called "module inclined arrangement" is shown in which each detection module is arranged obliquely at a predetermined angle from an orthogonal axis constituting the longitudinal direction.

Moreover, according to patent document 3, in both a line detector and a two-dimensional detector,

iii) the configuration of ii) in the case of panoramic shooting, and

iv) A modified example in which the module itself is formed in a rhombus shape and the coordinate system of the detection pixels of the two-dimensional array is inclined at a predetermined angle with respect to the orthogonal axis is shown.

In addition, Patent Document 4,

v) An example of arrangement of the line detector according to i) is shown.

As described above, in any of Patent Documents 2, 3, and 4, a gap, that is, a band-like insensitive region in which no radiation can be detected, is formed during scanning due to the inclined arrangement of the detector or each detection module in the scanning direction. In order to avoid the state remaining in the , the non-detection of such a dead area can be compensated for by post-processing (eg, sub-pixel method with neighboring pixels).

[Patent Document 1] US Patent 7127029B2 [Patent Document 2] Japanese Patent No. 4251386 [Patent Document 3] Japanese Patent No. 6033086 [Patent Document 4] WO2017/170408A1 However, even with the so-called oblique scan of any of Patent Documents 2 to 4, it can be said that there is a problem when considering a realistic product level in terms of securing sufficient imaging area and reducing the amount of computation required for reconstruction processing as post-processing. have. The structure of the inclination arrangement|positioning of the above-mentioned detector (or module) is divided roughly into the said "detector inclination arrangement|positioning" and "module inclination arrangement|positioning". Among these, in the case of "detector inclination arrangement", the coordinate system itself of the frame data output from the detector is inclined by a predetermined angle with respect to the scan direction (or the vertical axis direction orthogonal thereto). For this reason, in the middle of image reconstruction, for example, it is necessary to first put a process of repositioning the actual imaging system (object space) to the orthogonal coordinate system in which the scanning direction = the horizontal axis of the detector by the sub-pixel method. , this was a factor in the increase in the amount of computation. In addition, in the case of an imaging device that scans the detector of this "detector inclined arrangement", in consideration of the viewpoint of reducing the exposure dose, the opening of the slit arranged on the radiation source side is always inclined and spherical (diamond). It is necessary to adopt the size and attitude toward the whole of the radiation incident window of the model). In this respect, it is disadvantageous in terms of reduction of exposure dose as an imaging system that opposes each other through object space. On the other hand, in the case of "module tilt arrangement", among the detection signals output from each pixel of this tilt module, the imaging area contributing as the imaging area of the detector is a spherical shape ( part of the 矩形狀). For this reason, the pixel area effective for acquisition of a detection signal decreases, and there exists a problem that the imaging area decreases. In addition, both the "detector inclined arrangement" and the "module inclined arrangement" are intended to cover the entire image pickup area of the required size, and a so-called scan-type image pickup apparatus that scans the detector has also been proposed. However, only scanning one line detector increases the scan time, ie, the imaging time, and lowers the throughput. In addition, there is a situation in which the difference in sagittal phase becomes remarkable for objects including moving objects, and the device cannot withstand use. As an example of this, when the lung field or the like is used as the imaging area in the medical field, the above problem becomes present because the area itself is wide and includes a beating heart. In this case, imaging with the same sagittal phase of the heartbeat using ECG or the like is also assumed. However, it is easily assumed that imaging time becomes longer, patient throughput decreases, and inconvenience such as an increase in operation burden on the doctor is easily assumed. In addition, when a two-dimensional detection device having a configuration in which modules are two-dimensionally arranged by the above-described "detector tilt arrangement" and "module tilt arrangement" is constituted, scanning becomes unnecessary. However, for example, when targeting a wide imaging area, such as chest imaging, it is necessary to extend the wiring to the side of the module, so it is difficult to clear this problem and make it two-dimensional. In addition, even if it becomes two-dimensional by making full use of any wiring structure, its practicality is extremely insufficient. That is, in addition to the high component cost of the detection element, the wiring structure itself is complicated, thereby increasing the manufacturing cost of the detector and, by extension, an application device equipped with it. In addition, due to the complexity of the wiring structure, the size of the detector itself is inevitably increased, and there is also a thermal problem. In particular, in the case of a direct conversion type semiconductor detector, although superior in image quality, it faces instability in performance such as charge sharing and polarization. In addition, the manufacturing cost of the direct conversion type semiconductor detector is also relatively high, so that it is difficult to spread widely to the field of medical care or non-destructive inspection. For this reason, in the field, provision of the apparatus in which the balance was employ|adopted in both price and detection performance is awaited. In addition, as a case in which a desired imaging area is photographed by scanning the line detector, there is a case in which a portion in which the parallax due to the scan speed cannot be ignored is included in the object to be photographed. For example, this is the case when photographing a human chest in two dimensions. Although the movement of the lung field can ignore such a sagittal difference by, for example, the subject's breathing for several seconds, the movement of the myocardium due to the beating of the heart cannot be ignored in many cases. Even in such a case, it is desired to make the lag difference in data collection small enough to withstand practical applications. It is recognized that the sagittal difference to the extent that it can withstand practical use is 0.15 second in the lung field and 0.05 second in cardiac imaging, as an example in the present and clinical place.

The present invention was made in consideration of the disadvantages of the radiation detector accompanying the conventional "detector inclined arrangement" and "module inclined arrangement" configurations described above. Compensating for the effect of this, while enabling reconstruction of a high-resolution image by oblique scan, further reduction in exposure dose, data collection over a wider imaging area in a shorter time, and consequently manufacturing cost Its main object is to provide a radiation detection apparatus which can be easily introduced by an examination site, and a radiation examination system equipped with the apparatus.

In addition to achieving the above object, it is also desirable to provide a radiation detection apparatus capable of suppressing the lag in data collection to a level tolerable for practical use, and a radiation inspection system equipped with the apparatus.

Then, in order to achieve the above object, the main features of the radiation detection apparatus and radiation inspection system according to the present invention are as follows.

One explanatory example is as follows. A module column body in which a plurality of modules having a pixel arrangement in which pixels for detecting radiation are arranged two-dimensionally in a first direction and a second direction orthogonal to each other are arranged adjacent to each other in the first direction through a gap of a predetermined width (縱列体), wherein the module column has a long side along the first direction and a short side along the second direction, the long side is longer than the short side, and has an elongated spherical shape in plan view. A thin field detector formed of

The elongated detector is supported in a posture in which the second direction is directed to the scanning direction and the first direction is directed to a direction orthogonal to the scanning direction, and is movable in an oblique direction forming a predetermined angle with respect to the scanning direction. a detector support for supporting the

and moving means for moving the elongated detector in the oblique direction in response to a scan command during imaging to which the radiation is irradiated.

Preferably, the pixel arrangement is a pixel arrangement along rows and columns along the first direction in a two-dimensional plane formed in the first and second directions,

The elongation detector includes a plurality of elongation detectors arranged apart from each other in the second direction, and each of which is supported movably in the scan direction by the detector support portion;

Each of the plurality of elongated detectors is arranged to share a scan range up to a movement start position of another adjacent elongate detector in the scan direction in response to the scan command.

According to a preferred example,

The pixel arrangement is a pixel arrangement along rows and columns in the first direction on a two-dimensional plane formed in the first and second directions,

The elongation detector includes a plurality of elongation detectors arranged apart from each other in the second direction and each supported so as to be movable in the scan direction by the detector support unit,

Each of the plurality of elongated detectors is arranged to share a scan range up to a movement start position of another adjacent elongate detector in the scan direction in response to the scan command.

Furthermore, preferably,

The detector support portion,

Each of the plurality of elongated detectors is arranged to be spaced apart from each other by the same distance in the scan direction, and a movement distance in the scan direction accompanying the scan command is configured to be equal to each other. In this case, the plurality of elongated detectors are two. In addition, the number of the plurality of elongation detectors may be three.

In addition, there is provided a radiation inspection system having the above-described various types of radiation detection apparatus and a radiation generating apparatus for irradiating the radiation.

Here, the radiation includes X-rays or gamma rays, and in addition to medical and non-destructive testing, various radiations flying from space are also included. A pixel is the smallest unit of a physical detection pixel that receives radiation incident on the elongated detector. In addition, as described in the section of the background art, the "long length" of the elongated detector is a line of sight (in other words, a plane view (that is, a plane on which radiation is incident (including a radiation incident window)) viewed from the radiation side. (direction indicates the view along the arrow), the shape of the upper surface of the module column is long and slender. For this reason, the elongated spherical shape (that is, the module column body) extends in a direction (first direction) in which a plurality of modules are adjacently arranged in a column (however, including the gap between the modules). It has a long side and a short side (length shorter than the long side) extending in a direction (second direction) orthogonal to the long side. The direction along this short side, ie, the 2nd direction, coincides with the scanning direction for radiographic imaging. In addition, the elongation detector (module column) is moved in a direction inclined by a predetermined angle in the scan direction while maintaining the posture in which the direction of the long side coincides with the first direction.

At this time, the gaps (gap, gap) provided between the modules have a predetermined width in the first direction (long side direction) in plan view, and are parallel along the second direction (short side direction, scan direction). form a rectangle.

Incidentally, in the present disclosure, the term "elongate" means a strip shape such as the above-mentioned line, and also indicates a shape that may be called a strip shape, a line shape, a linear shape, etc. .

In this radiation detection apparatus and a radiation inspection system equipped with the same, an imaging area of a certain area is divided and scanned by a plurality of particularly preferably employed elongated detectors. That is, the plurality of elongated detectors are moved in parallel in the second direction, which is the scan direction, or the oblique direction thereof (substantially the second direction, that is, it can be regarded as the scan direction). Accordingly, each of the plurality of elongated detectors detects the radiation that has passed through the object in parallel. For this reason, compared with the conventional structure which scans one elongate detector and covers an imaging area, a scan time is shortened significantly.

For example, when a plurality of elongated detectors are spaced apart from each other in the second direction, which is the scan direction, and the scan sharing range is arranged so that they are equal, the total scan time is roughly shortened to "1/number of detectors".

Accordingly, when the image quality conditions are the same, mixing of scattered rays is reduced and the imaging time can be shortened. At the same time, a reduction in exposure dose can also be expected. This point of time is extremely important, especially for diagnostic devices in the medical field. In addition, the plurality of elongated detectors may be engaged in data collection of only the shared range in the scan direction to which each of the entire imaging area is assigned. That is, it is okay if a plurality of thin detectors share and scan one imaging area. This makes it easier to secure a wider imaging area while balancing the exposure dose and the scan time.

In addition, compared to the case of employing two-dimensional detectors in which the detection modules are arranged on one surface, the number of use of the later-described photon counting type or high-sensitivity integration type detection module, which is generally expensive, is small, and , the number of detection circuit channels is also small. Therefore, it is possible to suppress an increase in the manufacturing cost accompanying an increase in the component cost of the detection module, and it is easier to introduce it into the inspection site.

Incidentally, although the oblique movement direction is obliquely oriented with respect to the scan direction (second direction, short side direction), geometrically, of course, it may be slanted with respect to the orthogonal direction (first direction, long side direction) to the contrary. In reality, the predetermined angle in the inclination movement direction is designed to be about several to 20 degrees based on the pixel size and the width (width according to the number of pixels) along the second direction of the module column. For this reason, although the inclined movement direction may be defined as the scan direction, the original scan direction is the second direction (lateral direction), so it is natural to define that the movement direction for scanning is oblique to the scan direction. .

Incidentally, in the present disclosure, since the second direction is originally set as the scanning direction, the direction directed obliquely by a predetermined angle with respect to this scanning direction, that is, the second direction along the transverse direction of the module column body. can also be considered as a scan direction in practice.

In addition, the radiation detection apparatus according to the present disclosure includes a photon counting type processing circuit for measuring the number of photons of the radiation, respectively, and detecting the number of photons as the amount of the radiation in the plurality of elongated detectors It is preferable to configure it as a detector. That is, by such scan-type detection and photon counting processing, the circuit configuration is suppressed and the amount of heat generated is suppressed, compared to a circuit configuration in which the entire imaging region is built as a detection pixel or a direct conversion detector circuit configuration that directly converts radiation into an electrical signal. In addition to reduction of manufacturing cost due to , and component cost, superiority in detection performance such as improvement of detection sensitivity by photon counting, as well as high-precision substance identification by energy identification by processing based on the detection data It can also have advantages such as enabling

In addition, in the radiation detection apparatus according to another illustrative example, the plurality of elongated detectors include a plurality of first elongated detectors and a plurality of second elongated detectors having different lengths of the module columns,

a detector support for integrally supporting the plurality of first elongation detectors and the plurality of second elongation detectors;

Moving means for moving the detector support in the inclined direction at a constant speed when scanning by the radiation

equipped with,

The detector support part,

While supporting the plurality of first elongated detectors discretely from each other by a first separation distance in the second direction, the area of the imaging area covered by the plurality of first elongated detectors is scanned by the radiation. In a portion of the region, a second separation distance shorter than the first separation distance in the second direction together with a portion of the second direction of some of the first thin detectors of the plurality of first elongate detectors, the plurality of and configured to support the second elongated detectors mutually discretely.

In addition, there is provided a radiation inspection system having the above-described various types of radiation detection apparatus and a radiation generating apparatus for irradiating the radiation.

In this radiation detection apparatus and the radiation inspection system mounted therewith, the plurality of first thin detectors and the plurality of second thin detectors are all integrally formed by the detector support unit, and their postures are arranged in a first direction (orthogonal to the long side direction). direction) while being supported movably in a predetermined direction for scanning. The predetermined direction is preferably, as an example, an inclined direction set at a predetermined angle in the second direction (direction along the width of each elongated detector). The moving means moves the detector support according to a scan command from, for example, a front-end processor or the like. Thereby, scanning imaging of radiation is performed. For this reason, at the time of imaging, the plurality of first thin detectors and the plurality of second thin detectors are moved in the scanning direction while maintaining the postures aligned in the first direction by the detector support portion.

A beam of radiation (such as X-rays) irradiated from a radiation source passes through an object and is incident from the radiation incident windows of the first and second elongated detectors, and the number of photons of the beam is, for example, by each module. It is measured as the incident radiation dose.

According to the scanning operation of this radiation detector, the first and second elongated detectors (which may be referred to as line detectors, linear detectors, etc.) are aligned along the longitudinal direction (first direction) in plan view, and in the second direction. moving in a slanted direction.

According to the radiation detection apparatus of this other example, in addition to being able to enjoy various effects according to the above-described aspect, the following effects can also be obtained.

That is, in addition to the plurality of first thin detectors, a plurality of second thin detectors are arranged so that a local part of the imaging region of the plurality of first thin detectors can be detected more precisely in terms of sagittal difference. . Moreover, both the first and second elongation detectors are integrally moved for scanning, for example in the above-described oblique direction. For this reason, it is possible to reduce the lag difference due to the difference in the scan positions of data collection compared to the first thin detector, while the second thin detector also enjoys the above-described operational effects. For example, under a certain scan condition, the time difference between the scan start and the scan end of each of the plurality of first elongated detectors is 0.15 second. At this time, the mounting density of the plurality of second elongated detectors in the second direction (lateral direction) is, for example, three times that of the plurality of first elongated detectors, and the required A second elongate detector may be positioned to cover a localized area. Accordingly, the time difference between the scan start and the scan end of each of the plurality of second elongated detectors can be shortened to 0.05 seconds. This is in accordance with the needs required in the clinical setting, for example in human chest X-ray imaging.

In addition, since the plurality of second elongated detectors are shorter than the plurality of first elongated detectors all of the same length in the first direction, the degree of freedom in the arrangement of which part of the entire imaging area the second elongate detector is covered is high.

In addition, a configuration in which a portion of the plurality of first thin detectors also serves as the second thin detector in the first direction may be adopted. Thereby, the number of the 1st and 2nd thin detectors can be suppressed to a necessary minimum, the complexity of a structure can also be suppressed, and an unnecessary increase in component cost can also be avoided.

In the attached drawing,
BRIEF DESCRIPTION OF THE DRAWINGS It is an X-ray inspection system provided with the X-ray detection apparatus which concerns on 1st Embodiment of this indication, Comprising: A schematic perspective view explaining the structure provided with the 1st arrangement example of an elongate detector in the said X-ray detection apparatus.
[ Fig. 2 ] A partially broken plan view illustrating the X-ray detection device.
Fig. 3 is a diagram for explaining the arrangement and inclination movement of two elongated detectors (X-ray detectors) when the X-ray detection device is viewed in a plan view.
Fig. 4 is a plan view for explaining a second arrangement example that is another arrangement example of the elongated detector.
Fig. 5 is a plan view for explaining a third arrangement example that is another arrangement example of the elongated detector.
Fig. 6 is a plan view for explaining a fourth arrangement example that is another arrangement example of the elongated detector.
Fig. 7 is a plan view for explaining a fifth arrangement example that is another arrangement example of the elongated detector.
Fig. 8 is a plan view for explaining a sixth arrangement example that is another arrangement example of the elongated detector.
Fig. 9 is a plan view for explaining a seventh arrangement example that is another arrangement example of the elongated detector.
[ Fig. 10] A plan view for explaining an eighth arrangement example that is another arrangement example of the elongated detector.
Fig. 11 is a perspective view for explaining an example of a slender detector.
[ Fig. 12] A side view for explaining an X-ray detection module mounted on the elongated detector.
[Fig. 13] A plan view of the module.
[Fig. 14] A perspective view for explaining a schematic configuration centering on a scintillator block of a module.
[Fig. 15] A diagram for explaining the light emission operation of the scintillator.
[FIG. 16] A diagram exemplarily explaining the arrangement of SiPMs disposed on the lower surface side of the scintillator.
[Fig. 17] A diagram schematically explaining the arrangement and wiring of microcells for each pixel of the SiPM.
[Fig. 18] A block diagram illustrating a processing circuit for photon counting by energy discrimination of an output signal of SiPM.
[FIG. 19] A schematic flowchart illustrating a scan operation executed centering on a front-end processor of an X-ray inspection system.
[Fig. 20] Fig. 20 is a view for explaining a scan sharing range and a speed control profile for controlling the scan when the scan operation is performed with two thin detectors.
[FIG. 21] An explanatory diagram for explaining the scan sharing range in terms of the positional relationship between the imaging area and the image area.
[Fig. 22] A diagram for explaining the processing of data according to the amount of photons collected in the scan operation.
Fig. 23 is a diagram schematically explaining a state in which the collection frame data accompanying the inclination movement of the elongated detector, which is one step of data processing, is pasted to the reconstruction space;
[Fig. 24] A plan view for explaining a ninth arrangement example explaining a three-sided bubble, which is another arrangement example of the elongated detector.
25] A schematic perspective view illustrating a configuration in which an X-ray inspection system with an X-ray detection apparatus according to a second embodiment of the present disclosure is provided, wherein the X-ray detection apparatus is provided with a third arrangement example of the elongate detector.
26] A diagram for explaining the arrangement of the elongated detector (X-ray detector) when the X-ray detection device according to the second embodiment is viewed in a plan view.
Fig. 27 is a view for explaining inclination movement of the elongated detector when the X-ray detection device according to the second embodiment is viewed in a plan view;

Hereinafter, embodiments of a radiation detection apparatus according to the present invention and a radiation inspection system in which the radiation detection apparatus is mounted will be described.

Incidentally, this radiation detection device is a so-called indirect conversion type detection device that once converts incident radiation into light and electrically measures the dose as the number of radiation photons. In this radiation detection device, since the amount of light to be detected is as low as, for example, several tens of pW to sub-fW, it is preferable to detect by photon counting (photon counting), so-called weak light. it is light In the present embodiment, this weak light is obtained as light obtained by converting radiation (X-rays, etc.) into an optical signal, and the radiation is, for example, a kind of electromagnetic wave used in medical or non-destructive testing.

For this reason, since X-rays as radiation are handled in the following embodiments, the radiation detection apparatus is implemented as an X-ray detection apparatus, and the radiation examination system is implemented as an X-ray examination system suitable for medical use, non-destructive examination, and the like.

[First embodiment]

<Basic configuration>

The basic structure of the X-ray detection apparatus which concerns on this indication, and the X-ray inspection system in which the X-ray detection apparatus is mounted is shown in FIGS.

As shown in FIG. 1 , the X-ray inspection system 11 is a drive/control system in which an X-ray generator 21 and an X-ray detection device 22 are respectively provided and control their drive. to equip As a system of this drive/control system, a drive device 23 for driving the X-ray generator 21 and a drive device for controlling the movement of a collimator 33 mounted on the X-ray generator 21 ( 24). In addition, this drive/control system includes a drive device 25 incorporated in the X-ray detection device 22, while controlling the drive of these drive devices 23, 24, 25 and X-rays. Also included are a front-end processor 26 that controls data collection from the detection device 22, and a user PC (computer) 27 that processes the collected data.

Although the X-ray detection device 22 is described in detail below, as shown in FIGS. 1 and 2 , a pixel array PXay in which pixels (physical detection pixels), which are the minimum units to which X-rays are incident, are arranged in two dimensions. A plurality of unit elements in which circuits of an optical system and an electric system are formed on a semiconductor chip, usually called a module 132, are mounted in a spherical shape in plan view. Specifically, a plurality of these modules 132 are arranged in a column adjacent to each other with a gap SP ₂ of a predetermined width along one direction on the same mother substrate to form a module columnar body 132M ( see Fig. 3).

In this way, the X-ray detector 31 (hereinafter, this X-ray detector is referred to as a elongate detector or just a detector) has an elongated shape (strip, line, or linear shape) in plan view while accompanying the gap SP ₂ . is called) is composed. Incidentally, the planar view refers to a state in which the X-ray incident window 31W through which the X-rays are incident on the X-ray detector, that is, the elongated detector 31, is viewed from above. The elongated detector may, of course, be referred to as a longitudinal detector or a transverse detector depending on the arrangement direction thereof.

Since the module columnar body 132M has an elongated spherical shape in plan view, it has a long side 31L (first direction) and a short side 31S (second direction) orthogonal thereto. For this reason, as illustrated, it is possible to virtually set a rectangular coordinate system in which the height direction, the longitudinal direction, the short direction, and the height direction are the orthogonal axes (X, Y, Z).

In addition, the gap SP ₂ is set, for example, to a length of 0.5 to 2 pixels of the detection pixel in the first direction (Y-axis direction) along the long side 31L of the module column body 132M. has a certain width. For this reason, it becomes a spherical-shaped gap in planar view in which the size in the direction along the short side 31S becomes longer than the size in the direction along the long side 31L normally. The detection pixel does not exist in the part of this gap SP ₂ , and it becomes an insensitive area|region with respect to X-rays, and this insensitive area|region is located between the modules 132 adjacent to each other.

In the present embodiment, the long side 31L of the elongation detector 31 (shape, may be interchangeably referred to as the module columnar body 132M) is positioned along the first direction Y (Y-axis direction). while maintaining the X-ray scan while moving in the second direction Z (Z-axis direction) orthogonal thereto. That is, the second direction Z along the short side 31S is set as the scan direction SD.

However, in this embodiment, the X-ray detector 31 is actually set at a predetermined angle θ (usually, several degrees to 20 degrees) with respect to the second direction, that is, the scan direction SD from the viewpoint of image processing. ) while moving in the oblique direction MD (slanted direction), the X-ray scan is performed at a constant frame rate during the movement.

In addition, the direction in which the elongation detector 31 is moved may correspond to scan direction SD (2nd direction Z) itself, and may be made to correspond to the inclination direction MD. 1 to 3 illustrate the latter.

The so-called scan type which performs X-ray detection of the imaging area 22W which is a fixed two-dimensional area by making this elongate detector 31 scan in the scanning direction SD (inclination direction MD is also included). constitutes a composition.

In the positional relationship with the inspection object OB, which direction to set the scan direction SD, that is, the scan direction when the X-ray generating device 21 and the X-ray detecting device 22 are opposed through the object space. It is especially important in which direction (SD) should be set in a medical examination system. In this regard, for example, when diagnosing the chest of a person, an aspect in which the left and right directions of the chest are determined to be the scan direction (SD) or the vertical direction of the chest is determined to be the scanning direction (SD) is considered. . In that case, a mode in which a person is photographed in a state lying on a bed or photographing in a standing position is also considered.

In addition, the number of the elongate detectors 31 (X-ray detectors) mounted on one X-ray detection device 22, the number of scan times, and the like are taken into consideration in advance. In the example of Figs. 1 to 3, a certain imaging area 22W is scanned in the scanning direction SD (second direction Z), and the scanning is carried out by sharing the same distance or unequal distance from each other. Thus, a plurality of elongated detectors 31 of the same length and the same width are mounted discretely. That is, 2, 3, 4, ... in the scan direction (SD). As a result, a configuration in which equidistant or unequal distances are spaced apart from each other is adopted. In the case of the example shown in FIGS. 1-3, the elongate detector 31 is two (31 ₁ , 31 ₂ ), and it is arrange|positioned discreetly so that it may share scan sharing range R1, R2 (R1=R2) of equidistant distance. The scan sharing ranges R1 and R2 can also be said to be a section in charge of the scan in which each of the thin detectors 31 is in charge.

As shown in FIG. 3 , each of the plurality of elongated detectors 31 moves in the oblique direction MD in synchronization with each other in the state of X-ray irradiation from the X-ray generator 21 , a scan shared by itself Scan the sharing range R1(R2). Of course, it may be a scan in which the elongation detector 31 is moved in the scan direction SD.

In the case of equidistant, it is preferable from the viewpoint of simplification of scan control that the scan start timing and scan end timing of the plurality of elongation detectors 31 are the same. Incidentally, in the case of unequal distance, the timing of such start and end may be different and may be the same depending on the scan speed adjustment. There are various aspects of the scanning method of the plurality of elongated detectors 31 , which will be described by the following various embodiments and modifications.

When a plurality of elongated detectors 31 are provided to have scan sharing ranges R1 and R2 (R1 = R2) equidistant from each other as described above, one elongate detector is provided to scan the entire scan range (R1+R2). Compared with the configuration described above, the scan time can be roughly reduced to "1/number of detectors".

<Example of arrangement of X-ray detector>

Next, the device configuration will be described focusing on various arrangement examples of one or a plurality of X-ray detectors that can be mounted on the X-ray detection device 22 .

<First arrangement example>

1 to 3 again, the elongate detector 31 in the X-ray detection apparatus 22 according to the first arrangement example will be described in detail.

The X-ray detection apparatus 22 shown in FIG. 1 is mounted in a medical modality as an X-ray examination system, for example. Of course, it is not limited to a medical use, It is mounted preferably also to the apparatus of a non-destructive X-ray examination.

As a medical modality, an X-ray imaging apparatus which performs X-ray transmission imaging in a scan type is a preferable example. As the shape of the device, it is a system in which an X-ray detector and an X-ray generating device are positioned before and after the patient in an oral position, or X-ray generation so that the bed on which the patient lies is placed between the top and bottom. An example is a system in which the device and the X-ray detection device are respectively supported at both ends of the C-shaped arm.

The external shape of the X-ray detection device 22 is, as an example, a casing 41 formed in a substantially box shape having a constant thickness and a top and bottom size, as shown in FIGS. 1 to 3 . This casing 41 is loaded in the detector loading part 11D as a cassette of, for example, a detachable material of the X-ray inspection system 11 . X-ray tube 21X (point-shaped X-ray focal point F), a driving device 23 equipped with a high voltage generator for driving it, and a collimator 33 so as to face the detector loading section 11D The equipped X-ray generator 21 is arrange|positioned.

For this reason, as shown in FIG. 3, when such an opposition direction is assigned to the X-axis direction as a height direction, the longitudinal direction along the long side 31L of the elongation detector 31, ie, module columnar body 132M. ) (longitudinal direction: first direction) is set as the Y axis, and a rectangular coordinate system (XYZ) is set in which the short direction (width direction: second direction) along the short side 31S is the Z axis. do. In the present embodiment, as described above, the Z-axis direction (shorter direction, width direction) is the scan direction SD, and 2 in the oblique direction MD inclined by a predetermined angle θ with respect to the scan direction SD. One of the features is that each of the elongated detectors 31 ( 31 ₁ , 31 ₂ ) is moved in synchronization.

Of course, as will be described later, the Z-axis direction = the scanning direction SD = the detector movement direction, that is, the predetermined angle θ = 0 may be set to perform scanning in synchronization with each other.

For the movement of these two elongation detectors 31 ( 31 ₁ , 31 ₂ ), as shown in FIG. 3 , a guide rail 42 and a driving device 43 facing in the inclined direction MD are provided. The two elongated detectors 31 ( 31 ₁ , 31 ₂ ) are respectively mounted on the mother board 44 , so that the mother board 44 is passed through the case or as it is, with a U-shaped one support frame ( 45) (support). Two elongation detectors 31 ( 31 ₁ , 31 ₂ ) are fixed to both arm portions of the support frame 45 , respectively.

The drive apparatus 43 is comprised by the linear actuator which uses an electric motor as a drive source, for example, and moves the support frame 45 with the drive. The back surface of the support frame 45 is locked by the guide rail 42 . The guide rails 42 are arranged obliquely at a predetermined angle θ with respect to the scan direction SD (second direction), that is, in the oblique direction MD. For this reason, when the driving device 43 is driven, the support frame 45 moves while being linearly guided by the guide rail 42 . Accordingly, the two elongated detectors 31 ( 31 ₁ , 31 ₂ ) are moved in the oblique direction MD.

Of course, when the two elongated detectors 31 are moved next to each other, that is, in the short direction Z (second direction) along the short side 31S, the guide rail 42 is the short It may be provided parallel to the direction (Z).

Two or more guide rails 42 may be provided in parallel along the inclination direction MD or the transverse direction Z (= scanning direction). In addition, as another example of the driving device 43 and the guide rail 42 , a device in which a “drive source + guide rail” called a uniaxial actuator also serving as a guide rail guide function is integrated on the back side of the support frame 45 . Excretion (配設) is also free.

In either configuration, the driving source of the driving device 43 is placed under the control of the front-end processor 26, and by feedback control using a movement sensor (not shown) or open control without using it, Likewise, position control (movement control) is performed linearly in the transverse direction (scan direction SD or oblique direction MD) of the elongation detector 31 at only a predetermined speed.

In the above-described collimator 33, two slits 33A and 33B of elongated spherical shape are formed. The collimator 33 is controlled to move in the oblique direction MD or the scan direction SD in synchronization with the movement of the elongation detector 31 inside the X-ray generator 21 . This control is executed by the collimator drive unit 24 , which is placed under the control of the front-end processor 26 . This collimator drive device 24 is provided with, for example, an electric pulse motor, and is comprised.

The area of each of these two slits 33A, 33B is the distance between the X-ray focus F in the height direction X and the same slit, and the X-ray focus F and the elongation detector ( 31) (more specifically, the X-ray incidence window 31W) is set to a predetermined value so as not to cause loss of the X-ray irradiation field due to the precision of the scan travel, etc. It is set a little wider by the minute you set the margin.

In addition, although the linear moving speed of the collimator 33 is different by the above ratio, it is synchronized with the scan speed of the two elongation detectors 31 ( 31 ₁ , 31 ₂ ) located below it, It moves in the oblique direction (MD) or the scan direction (SD). For this reason, during the X-ray scanning operation, the collimated two X-ray fan beams XB always capture the X-ray incident windows 31W of the two elongated detectors 31 respectively in the oblique direction MD or scan. It is configured to move linearly in the direction SD.

For this reason, the X-ray flux emitted from the X-ray generator 21 is formed into two fan-beam-shaped X-rays: (XB), passes through the inspection object OB, and is The elongated detector 31 ( 31 ₁ , 31 ₂ ) is incident on each X-ray incident window 31W, and is detected by a detection pixel described later.

In addition, in this embodiment and this arrangement example, an image is reconstructed based on the data detected by the two elongate detectors 31 ( 31 ₁ , 31 ₂ ). In this reconstruction operation, data is mapped to the reconstruction space, but the gap SP ₂ between modules in the reconstruction space, that is, each of a plurality of pixels corresponding to the dead region, is caused by the mechanical tilt movement of the detector itself, Partial pixels provided by a fraction of each of the neighboring pixels involved in the movement are provided. For this reason, the pixels in the insensitive area are supplemented by the sub-pixel method using the pixel values and area ratios of fractions of the pixel values. In this complementary method, the interpolation precision is higher as the partial pixels are provided, compared to the method of externally inserting (estimating) only from neighboring pixels.

As described above, according to the first arrangement example, the two elongated detectors 31 ( 31 ₁ , 31 ₂ ) have a longitudinal direction Y along the long side 31L, as shown in FIG. 2 for easy understanding. While maintaining the orientation facing each other, they are disposed discretely at an equidistant distance from each other in the scan direction SD. Accordingly, each elongate detector 31 is in charge of X-ray scanning of the scan sharing range (R1 = R2) of the same distance in the scan direction SD. The imaging area 22W of a desired fixed area is determined by the sum of the scan sharing ranges R1 and R2 of two equal scan distances. In addition, since this X-ray detection apparatus 22 is a scan type, each elongate detector 31 stops from the acceleration period from an initial position P _1st (P _2st ) to a constant speed movement, and constant speed movement. In consideration of the deceleration section up to the position (P _1FIN (P _2FIN )), an overlap section (OV) is provided in the scan sharing ranges (R1, R2) (see Fig. 2).

Here, a method of setting the predetermined angle θ in the case of scanning each elongation detector 31 moving in the oblique direction MD will be described.

The predetermined angle θ is, as shown in FIG. 3 , a plurality of detections arranged in a line along the transverse direction Z (second direction) among the pixel arrays PXay arranged in each module 132 of each elongate detector 31 . It is set based on the ratio of the distance which the pixel Pin shows: (A1), and the width|variety of the space|gap SP ₂ in the longitudinal direction Y (1st direction): (A2). Specifically, this predetermined angle: (θ) is the distance: (A1), width: (A2), and the distance of the pixels arranged in the longitudinal direction (Y) when it is assumed that the pixels are arranged in the space SP ₂ . Based on the number n (where n is a positive real number excluding 0),

θ≥tan ^-1 n·(A2/A1)

is set by In particular, the number of pixels n may be a positive integer.

In addition, when the length of the detection pixel Pin in the longitudinal direction Y (first direction) is b, the width: (A2) is preferably a value of b = (1/2)b to 2b. do.

Incidentally, detailed configuration examples of the detection pixel Pin and the pixel array PXay will be described above.

<Second arrangement example>

A second arrangement example is shown in FIG. 4 . In the case of the X-ray detection apparatus 22A according to this arrangement example, the two elongated detectors 31 are respectively arranged at equal intervals in the scan direction SD, that is, in the short direction Z along the short side 31S, have.

In this case, since the two elongation detectors 31 do not move in the oblique direction MD, as will be described in detail below, in image reconstruction, for pixels corresponding to the insensitive area due to the gap SP ₂ between modules, Pixel values are interpolated by external insertion processing.

<Third arrangement example>

A 3rd arrangement example is shown in FIG. In the X-ray detection device 22B according to this arrangement example, the three elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) are respectively installed in an oblique direction MD having a predetermined angle θ with respect to the scan direction SD. is configured to move to Similar to the first arrangement example, the three elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) are arranged equidistant from each other in the scan direction SD, and each of the scan sharing ranges R1, R2, R3 ) is set in the same way. For this reason, the three elongation detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) move in the oblique direction MD with respect to the scan direction SD, and the three elongate detectors 31 are divided by three equal parts. Perform a scan. At the time of this scan, even in the insensitive area due to the gap SP ₂ between the modules 132 adjacent to each other, since the three elongated detectors 31 move obliquely and perform a mechanical oblique scan, it is insensitive at the time of image reconstruction. Reconstructed pixels originating in the region are also given pixel values by a fraction of that of neighboring related pixels. Accordingly, in each reconstructed pixel, pixel values are interpolated by a sub-pixel method of synthesizing such fractional pixel values in an area ratio, for example.

<Fourth arrangement example>

A fourth arrangement example is shown in FIG. 6 . The X-ray detection apparatus 22C according to this arrangement example uses three elongate detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) according to the third arrangement example described above and the second arrangement example described above, respectively. They are discretely arranged at equal intervals in the scan direction SD, that is, in the transverse direction Z along the short side 31S.

In this case, since the three elongation detectors 31 do not move in the oblique direction MD, in the image reconstruction, for the pixels in the insensitive area due to the gap SP ₂ between the modules 132, the extrapolation process is required. pixel values are interpolated by

<Fifth arrangement example>

A fifth arrangement example is shown in FIG. 7 . As shown in FIG. 7, the X-ray detection apparatus 22D which concerns on this arrangement example has shown the state incorporated in the apparatus so that the scanning direction SD may become a gravitational direction or an oblique direction. This assumes, for example, a case in which the patient takes an X-ray photograph of the chest in an oral position. For example, the two elongation detectors 31 ( 31 ₁ , 31 ₂ ) move in the direction MD inclined by a predetermined angle θ with respect to the transverse direction Z corresponding to the vertical direction with respect to the chest, A shared scan can be performed.

Also in this case, of course, three or more elongation detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) may be formed discretely in the scan direction SD. In addition, the moving direction of each detector may be configured to coincide with the scan direction SD itself.

<Sixth arrangement example>

A sixth arrangement example is shown in FIG. 8 . The X-ray detection apparatus 22E according to this arrangement example employs one elongate detector 31, and the elongate detector 31 is inclined in a direction MD by a predetermined angle θ with respect to the scan direction SD. A moving configuration is adopted. By the position control (movement control) leading to the acceleration (slow start) period, the constant speed period, and the deceleration (slow stop) period by driving of the drive device 43 (refer FIG. 19 mentioned later), this one elongate detector 31 moves in the oblique direction MD along the guide rail 42 from the start position P _ST to the end position P _FIN . Accordingly, the entire imaging area 22W is covered.

Of course, in this sixth arrangement example, without setting the inclination direction of the predetermined angle θ, one elongated detector 31 made upright along the Y-axis direction (first direction Y) is set in the Z-axis direction (the second direction). You may make it move toward the two directions Z), ie, the scan direction SD. That is, you may employ|adopt the structure of movement direction = scanning direction SD.

<Seventh arrangement example>

A seventh arrangement example is shown in FIG. 9 . The X-ray detection apparatus 22F according to this arrangement example sets the scan sharing ranges R1 and R2 shared by each of the two elongated detectors 31 described with reference to FIGS. 2 to 3 to R1 in the scan direction SD. The configuration set by ≠R2 is adopted. In this example, R1>R2 is set. The scan times of the two elongated detectors 31 ( 31 ₁ , 31 ₂ ) are different from each other (when the movement speed is the same), and the detection data of both detectors 31 ( 31 ₁ , 31 ₂ ) are respectively analyzed in the same reconstruction space. By properly mapping, image reconstruction becomes possible.

In this way, when each of the plurality of elongated detectors 31 is responsible for scanning ranges of unequal distances, it is effective when trying to cover as much as possible the same object or the same site with one detector.

<Eighth arrangement example>

An eighth arrangement example is shown in FIG. 10 . In the X-ray detection device 22G according to this arrangement example, the movement start positions of the plurality of elongated detectors and other settings of the movement directions are described.

In the case of FIG. 10 , it does not move from one end to the other end of each scan range equally or unevenly allocated to each of the plurality of elongated detectors, but rather in the center of the scan direction SD of the imaging area 22W. The two elongated detectors 31 ( 31 ₁ , 31 ₂ ) initially positioned so as to be adjacent to each other move in opposite directions after the scan starts, so that these scan sharing ranges R1 and R2 are 22W).

More specifically, the two elongated detectors 31 ( 31 ₁ , 31 ₂ ) move only the accompaniment period RB of the illustrated outbound route, for example, in the -Z axis direction of FIG. 10 . . The thinness detector 31 ₁ at the head of the accompaniment direction is used as a running section (acceleration section) RJ ₁ that is a part of the accompaniment period RB, and when the running section RJ ₁ ends, it travels at a constant speed as it is. , and moves in the oblique direction MD inclined at a predetermined angle θ in the -Z-axis direction.

On the other hand, one of the elongation detectors 31 ₂ also moves in the oblique direction MD inclined at a predetermined angle θ in the -Z axis direction until the end point of the outgoing accompaniment period RB, but the accompaniment period RB ) at the end point P _K , the movement direction is reversed in the oblique direction MD at a predetermined angle θ in the +Z axis direction (right direction in FIG. 10 ). For this reason, again, after the movement reversal, one slender detector 312 steers _the said running section _RJ2 , and then moves to constant speed running and moves to the inclined inclination direction MD.

Although not shown, this movement is controlled by a drive mechanism separately mounted to each detector. Although the guide rail is not shown in figure, it may exist in common to each detector, and may exist mutually independently.

Accordingly, the initial region R1 _N in which the detection data is difficult to be stable because it is the running section RJ ₁ of the one of the elongation detectors 31 ₁ is scanned by the constant speed running of the one of the elongation detectors 31 ₂ . . For this reason, the entire area of the scan direction SD is covered by the constant speed travel section of both detectors 31 . For this reason, although it is an acceleration/deceleration running, the area in which the detection data becomes unstable is reduced, and only the detection data of a deceleration area needs to be processed appropriately.

In addition, in the X-ray detection apparatuses 22 and 22A-22G mentioned above, you may arrange|position the elongate detector by any of the 1st - 8th arrangement examples.

<Detailed configuration of the slender detector>

Next, with reference to FIGS. 11-17, the structure and operation|movement of each of the above-mentioned elongate detectors (X-ray detector) 31 are demonstrated. Here, the same reference numerals are assigned to components having the same or equivalent functions as the above-described components, and descriptions thereof are omitted or simplified.

The external appearance of this elongate detector 31 is illustrated in FIG. The elongated detector 31 has a case 131 in the shape of a rectangular parallelepiped elongated as a whole, and the case 131 is moved in the scan direction SD or its direction by the drive device 43 . It is fixed and mounted on the support frame 45 which moves in the inclination direction MD which has a predetermined angle θ in the scan direction SD.

<Outline of layout configuration of X-ray detection module>

Next, the configuration of each of the plurality of X-ray detection modules 132 (hereinafter, simply referred to as 'detection module' or 'module') equipped with each elongated detector 31 will be described in detail.

Fig. 11 shows a plan view of the elongated detector 31, which is seen when the upper surface (ceiling portion) of the case 131 is partially broken and viewed in plan view in the direction of the arrow XB (incident X-ray), 12 is a side view of the detection module 132 viewed from one side in the longitudinal direction (Y-axis direction).

As shown in FIG. 12 , each detection module 132 includes a mother substrate 44 (refer to FIG. 5 ) accommodated in the case 131 , and placed on the mother substrate 44 , for example, one A semiconductor chip 142 is provided. In addition, each detection module 132 includes a scintillator block 143 mounted on the semiconductor chip 142 and biased in a certain range on one side of the semiconductor chip 142 in the lateral direction (Z-axis direction); An ASIC (application specific integrated circuit) block 144 mounted on the semiconductor chip 142 separated from the scintillator block 143 and occupying a certain range on one side of the other side in the lateral direction of the semiconductor chip 142 . to equip

In addition, the mother board 44 may be directly mounted on the support frame 45 without using the case 131 .

In this configuration, one of the major characteristics of the detection module 132 is that the scintillator block 143 and the ASIC block 144 are adjacent to each other on the surface of one semiconductor chip 142 and are spaced apart from each other. The scintillator block 143 is an element that detects photons (photons) of the incident X-ray beam XB as light pulses, as will be described later.

In addition, under the scintillator block 143 , a layer of silicon photomultiplier (SiPM) is formed on the surface of the semiconductor chip 142 . This SiPM is an element that converts a light pulse corresponding to each photon of the incident X-ray beam XB into an electric pulse signal, as will be described later. For this reason, the electric pulse output from the SiPM is transmitted to the adjacent ASIC block 144 through the wiring pattern formed on the surface of the semiconductor chip 142 . This layout structure is also one of the big features. The ASIC block 144 performs discrimination processing of the photon counting type capable of distributing the energy each X-ray photon has to a plurality of energy bins (ranges) by discriminating the electric pulses to a plurality of levels of threshold values, and the discrimination Outputs a digital signal according to the result.

In particular, the X-ray beam XB is irradiated to the detection pixels formed on the upper surface of the scintillator block 143 in the height direction (X-axis direction), and fluorescence is emitted from the emission surface corresponding to each detection pixel on the lower surface of the scintillator block 143 . ) as a foot (發). That is, the electric pulse signal detected as the X-ray: (XB) irradiated along the height direction is converted into fluorescence is transmitted in the lateral direction (Z-axis direction) to reach the ASIC block 144 . For this reason, as schematically shown in FIG. 12, when it sees from the Y-axis direction, the L-shaped signal transmission path L is comprised.

By the adoption of this L-shaped signal transmission path L, as shown in FIG. 13, among the four sides of each detection module 132 in plan view, the upper and lower side surfaces US in the longitudinal direction (Y-axis direction) LS) and the left side surface LFS in the lateral direction (Z-axis direction) are empty. Accordingly, it is possible to arrange another detection module 132 opposite to the empty side surfaces US, LS, and LFS. That is, by disposing the plurality of detection modules 132 adjacent to each other in one or two dimensions, the detection area of X-rays may be increased. In this embodiment, disposing one or a plurality of other detection modules 132 on each of the upper and lower sides US and LS of one detection module 132 adopts a "two-sided buttable structure". ' is called.

In addition, arranging one or a plurality of other detection modules on each of the upper and lower side surfaces US and LS and the left side surface LFS of one detection module 132 is referred to as "adopting a three-sided bubble structure", have. However, when the three-sided bubble structure is adopted, there is one or plural other detection modules adjacent to the upper and lower side surfaces US and LS, but the number of detection modules adjacent to the left surface LFS is limited to one At the same time, it is preferable to reverse the fitting in the longitudinal direction (Y-axis direction).

The elongation detector 31 according to the present embodiment employs such a "two-sided bubble structure". That is, the plurality of detection modules 132, as described above, in a longitudinal direction (Y-axis direction) with a small gap (gap) SP ₂ of a predetermined width in a vertical line (Fig. 3 and 11), it is mounted on the mother substrate 44. This gap SP ₂ is set, for example, to the same width as that of one or a plurality of detection pixels. For example, if the detection pixel Pin is 250 x 250 mu m, it is an integer multiple of 250 mu m, 500 mu m, or the like. Of course, even if it is not necessarily an integer multiple, you may set the gap SP ₂ of 0.5 times, 1.5 times, for example.

Accordingly, as described above, an elongated module columnar body 132M extending in the longitudinal direction made of a plurality of detection modules 132 is formed. The case 131 is formed so as to contain the mother board 44 on which the module column body 132M is mounted.

Incidentally, on the surface of the upper surface of the case 131 opposite to the module columnar body 132M, an open spherical X-ray incidence window 31W formed of a material that transmits X-rays or opened. ) is formed. In particular, the X-ray incident window 31W preferably faces only the scintillator block 143 arranged in a row as described later, and the part of the ASIC block 144 to be described later is formed by a soft plate (鉛板). P _pb ) is preferably covered (see FIG. 11 ).

In addition, as schematically shown in FIG. 20 to be described later, on the front surface of this X-ray detection device 22, that is, on the X-ray incident side, a grid for reducing scattered rays of X-rays from the inspection object OB. You may provide (GR) integrally with the said apparatus 22 or separately. The grid GR includes a plurality of absorption foils with large X-ray absorption, for example, in the scan direction SD, for each scan sharing range R1 (R2) of the elongated detector 31 . It is formed so as to form a focusing grid obliquely focused toward the line focal point F. Thereby, the scattered rays are effectively removed and it is contributing to the improvement of the contrast of an X-ray image. In particular, in the case of a photon counting detector, since substances can be discriminated by identification of energy information, detection of scattering radiation leads to deterioration of the accuracy of substance discrimination, so it is important to remove scattered rays by a grid.

<Detailed structure of X-ray detection module>

[Scintillator Block]

Next, a detailed structure of each detection module 132 will be described. 14 and 15 , the scintillator block 143 includes a plurality of columnar scintillators 143A (columnar bodies) arranged at upper and lower ends in the longitudinal direction, and further They are bundled together so as to form one block densely with a predetermined gap from each other in the planar direction. Each scintillator 143A is a light-emitting material made of an inorganic crystal that emits fluorescence in response to X-rays, and the light-emitting material includes GAGG, GFAG, BGO, LYSO, LuAG, CsI, or SrI ₂ (Eu). etc. are mentioned, of course, other fluorescent substances may be sufficient. Each scintillator 143A is, for example, several millimeters in length, and has a spherical shape of, for example, 250 µm x 250 µm in size of the upper and lower surfaces.

For this reason, by bundling the plurality of scintillators 143A, the block upper surface ( 143U) and block lower surface 143L (refer to FIG. 12) are constituted. In the block upper surface 143U, the upper surface of each scintillator 143A forms the detection pixel P _in of the present detection module 132 , that is, the detector 31 . The size of each detection pixel P _in is the same as the size of the upper surface of each scintillator 143A, and is, for example, 250 µm×250 µm. With this dense bundle structure, the block upper surface 143U functions as an X-ray incident surface in which the detection pixels P _in are arranged two-dimensionally. The number of detection pixels P _in is determined according to the number of scintillators 143A to be disposed. By changing the size of the upper and lower surfaces of each scintillator 143A, the size of the detection pixel can be appropriately changed.

Similarly, in the block lower surface 143L (refer to FIG. 15A), the lower surface (bottom surface) of each scintillator 143A has the same size as the detection pixel size: 250 µm × 250 µm, if described in the above example. The branch functions as an emitting surface (Bout) of X-rays. The block lower surface 143L of the scintillator block 143 functions as a fluorescence emission surface by the two-dimensional arrangement of a plurality of the emission surfaces Bout. The fluorescence emission surface is disposed to directly or indirectly (via an optical interface, for example) directly or indirectly (via an optical interface) to the surface of a light sensing layer (to be described later) on the semiconductor chip 142 .

In addition, at least a part of the peripheral surface of each of the plurality of scintillators 143A with respect to the adjacent scintillator is covered with a light blocking material in the height direction X. This is to prevent X-ray photons incident on each detection pixel P _in from leaking to the adjacent scintillator 143A, or to reduce the leakage to the extent that there is no problem in terms of noise reduction or the like. Ideally, the side surface excluding the lower surface (the emission surface Bout) of each scintillator 43A and, in some cases, the upper surface (the surface forming the detection pixel P _in ) may be covered with a light blocking material. In this case, the light-shielding material covering the upper surface needs to be a member that transmits X-rays.

Incidentally, the above-described dense bundle structure of the scintillator block 143 means a structure that is bundled after manufacturing, and may be bundled after cutting each scintillator 143A, and the bundle of scintillator materials is cut with a laser cutter. It can also be processed so that it may have the structure similar to the above-mentioned bundled|bundling, such as digging a groove|channel with a furnace.

In this way, since the periphery of each of the plurality of scintillators 143A is covered with a light-shielding material to form a dense bundle structure, the size of each pixel division including the detection pixels P _in of the two-dimensional array is, in fact, For example, a scintillator having a size of 250 μm × 250 μm (200 μm × 200 μm) is surrounded by a light blocking material having a thickness of 25 μm, and the thickness of the light blocking material such as a detection pixel (P _in = 250 μm × 250 μm) is increased by the thickness of the light blocking material. . Accordingly, the detection pixels P _in having an effective detection function have a structure in which they are mutually discretely arranged two-dimensionally in the plan view.

When a photon (photon) of X-rays is incident on each scintillator 143A, when the photon propagates through the inside of the scintillator 143A, a scintillation that excites fluorescence as a stochastic phenomenon is performed. causes The fluorescence generated in this way is emitted as fluorescence from each emitting surface Bout while reflecting the inside of the scintillator 143A or propagating linearly. This amount of fluorescence is in the category defined as faint light.

[Semiconductor Chip]

FIG. 13 schematically shows the chip upper surface US in the height X direction of the semiconductor chip 142 along the arrow (VIII-VIII) line shown in FIG. 12 . This chip upper surface US is opposed to the block lower surface 143L of the above-described scintillator block 143 via an optical interface (for example, an adhesive layer made of a light-transmitting resin) not shown.

The semiconductor chip 142 undergoes, for example, cleaning, pattern printing, etching, cleaning, electrode formation, wafer inspection, dicing, and the like on the surface of a silicon wafer to undergo photoelectric conversion. A circuit pattern and a wiring pattern for wiring the circuit to the ASIC block 144 at the rear stage are formed. This semiconductor chip 142 is mounted on a mother substrate 44 (refer to FIGS. 12, 14, and 15 (A)), and the mother substrate 44, the semiconductor chip 142 and the ASIC block 144 are Electrical connection (bonding connection in this embodiment) is performed after the mounting.

In this silicon semiconductor chip 142, the magnitudes YL and ZL in the longitudinal direction Y and the lateral direction Z are set to YL<ZL as an example, and will be described in a plan view according to the example of FIG. 13 . On the lower surface, it is formed in the shape of a long rectangle. For this reason, the area|region of the chip|tip upper surface US has also become a horizontal rectangle shape similarly.

The region of this chip top surface US is described with the example of FIG. 13 , in order from the left, one elongated power supply pad region R _pad1 , is formed biased to the left and functions as a cell region. Area (R _SiPM ) of the pliers (SiPM), a gap area (R _space ) provided for cooling purposes or electromagnetic mutual interference prevention, etc., ASIC area (R _ASIC ) for mounting the ASIC block 144, and It is occupied by the other thin input/output pad area R _pad2 .

ㆍPhotoelectric conversion circuit (silicon photomultiplier (SiPM))

Of these, as shown in FIG. 16A , the SiPM region R _SiPM is entirely formed as a photo-sensing layer, and forms the block lower surface 143L of the plurality of scintillators 143A described above. It faces the plurality of emission surfaces Bout (that is, the output surface of the detection pixel P _in ). The SiPM region R _SiPM is formed as a silicon photomultiplier (SiPM) 151 functioning as a photoelectric conversion circuit through pattern creation by the above-described photolithography.

Specifically, as shown in FIGS. 16A and 16B , this SiPM: (151) is two-dimensionally formed in the SiPM region (R _SiPM ), and further described above. A plurality of light-receiving pixels P _opt opposing each of the plurality of emission surfaces Bout (ie, the output surfaces of the detection pixels P _in ) are formed. In each of the plurality of light-receiving pixels P _opt , a plurality of microcells MS are formed as a photoelectric conversion element array as a micro region each having a photodetector element.

In addition, as can be seen from FIG. 17 , in the SiPM region R _SiPM , a wiring pattern WPpg for connecting power and earth to each microcell MS, and a wiring pattern WPpg connected to each microcell MS are drawn out ( A part of the output wiring pattern WPout is formed. The remaining portion of the output wiring pattern WPout passes through the adjacent gap region R _space and reaches a predetermined bump bonding position of the ASIC region R _ASIc at once. That is, one of the features of this output wiring pattern WPout is that it is wired in the lateral direction Z along the chip top surface US of one semiconductor chip (silicon chip) 142 as will be described later. .

Each microcell MS has an avalanche photodiode (APD: Avalanche Photo-) which is a photoelectric conversion element so as to be driven in, for example, Geiger mode, as shown in FIGS. 16C and 16D . Diode) and quench resistance (R) are built in, and the time constant at the time of electric pulse generation by this quench resistance (R) and the capacitance component (C) inherent to the cell circuit (time constant)數) is to be determined.

16 shows the SiPM region R _SiPM functioning as the cell region as a center ((A) of the same figure), and further, a plurality of detection pixels P _in that form the region R _SiPM two-dimensionally. ) (having a size corresponding to the cross-sectional area in the transverse direction of each scintillator 143A) ((A) to (C) in the same figure) and one light-receiving pixel formed inside each detection pixel P _in , respectively (P _opt ) ((C) of the same figure) and a plurality of microcells MS ((D) of the same figure) constituting a photoelectric conversion element array formed in each of the light-receiving pixels P _opt are schematically shown indicates.

In addition, in this embodiment, each detection pixel P _in and each light receiving pixel P _opt both form a square in plan view, and the center position O of both is made to coincide in plan view. have. That is, in consideration of light collection efficiency from each detection pixel P _in provided by the scintillator 143A and light separation between adjacent light receiving pixels P _opt , such centering is preferable.

In addition, as can be seen from the above example, in the region opposite to each detection pixel P _in on the chip upper surface US, a photoelectric conversion element array made of microcells MS, that is, the light receiving pixel P _opt itself A light sensing region R _act occupied by is formed. Since the area of the light sensing region R _act is smaller than that of each detection pixel P _in , a region in which the avalanche photodiode APD is not disposed remains in the opposite region. Assuming that this remaining area is referred to as a light-insensitive area R _dead , the light-dead area R _dead exists over four peripheral sides of the light-receiving pixel P _opt .

As described above, according to the pixel configuration of the present embodiment, it is characterized in that the size relation is set to "light-receiving pixel P _opt < detection pixel P _in ", leaving light-sensitive region R _dead .

Specifically, if the size of the detection pixel P _{in in} the vertical direction (Y) and in the horizontal direction (Z) is W _L , W _H , respectively (W _L =W _H ), those of the light-receiving pixel P _opt ( W _L1 , W _H1 ) is smaller than W _L (=W _H ) by a selected value between 5 and 45% in length and width, respectively, and W _L1 < W _H1 is set. That is, as an example, in the longitudinal direction (Y), W _L =W _L1 +2W ₁ (W ₁ : width of the light-insensitive region (R _dead )), and in the lateral direction (Z), W _H =W _H1 +2W ₂ ( If W ₂ : width of light-insensitive region (R _dead )), 25% of the total width (W _L ) is secured as width (W ₁ ) of light-insensitive region (R _dead ) in the longitudinal direction (Y) In addition, as the width W ₂ of the light-insensitive region R _dead in the lateral direction Z, it is set so as to leave only 5% of the total width W _H .

Of course, the widths W ₁ , W ₂ of the light-sensitive region R _dead may be appropriately changed in the range of 5 to 45% depending on the required photodetection characteristics. For example, under the above conditions, the ratio of the width W ₁ is 10%, and the ratio of the width W ₂ , may be 20%.

The reason why this light-receiving pixel P _opt is made small by the said 5-45% arbitrary selection value is demonstrated qualitatively with the schematic diagram of FIG. 15 and (B) at the bottom. The numerical value itself is changed by design conditions.

15, (B) at the bottom is a photo-sensing area (R _act ) of each of a plurality of light-receiving pixels (P _opt ) adjacent to each other in the longitudinal direction (Y) and the lateral direction (Z) (that is, a plurality of microcells ( MS)), and a plurality of fluorescence emission surfaces Bout adjacent to each other in the longitudinal direction (Y) and the lateral direction (Z) on the lower surface 143L of the SiPM: 51 (that is, the detection pixel P _in ). The output surface of ) is shown schematically in the longitudinal direction (Y). In this figure, the distribution of the fluorescence L _scin emitted from each emission surface P _out in the horizontal axis direction Z is further shown. The emitted fluorescence L _scin is directly opposite from the inside of each scintillator 143A (columnar body) or indirectly from the exit surface Bout while being reflected from the wall surface through the optical interface 152 It is incident on each light sensing region R _act . For this reason, the distribution of the fluorescence L _scin statistically represents a mountain-shaped curve indicating the highest light quantity at the center of the lateral direction Z of each light sensing region R _act . For this reason, in the distribution curve of the fluorescence (L _scin ), there is an overlapping portion (OVC) between the photo-sensing regions (R _act ) adjacent to each other.

Components of the curved portion OVC where the fluorescence L _scin overlaps each other becomes a crosstalk component of light to the adjacent light sensing region R _act . For this reason, if the amount of light in the overlapping curved portion OVC is sufficiently lowered, the crosstalk component to the adjacent light sensing region R _act can also be reduced, so that the light sensing region R occupied by each light receiving pixel P _opt . _act ) makes the ratio of the area occupied by it small. In particular, at the boundary position between the detection pixels P _{in in} the vertical direction (Y) and the horizontal direction (Z), the light-receiving pixel (P _opt ) and the light-sensing pixel so that the light amount level of the overlapping curved portion (OVC) is sufficiently small By determining the area ratio of the region R _act (light receiving pixel P _opt > light sensing region R _act ), such crosstalk can be sufficiently suppressed. Also, even if there is a position difference between the light-receiving pixel P _opt and the light-sensing region R _act in the longitudinal direction (Y) and the lateral direction during manufacture, it can be absorbed and the above-mentioned magnitude relationship can be maintained.

On the other hand, as described in FIG. 17 , a plurality of small microcells MS are formed in a two-dimensional array in the light-receiving pixel P _opt . The smaller the area of each of the microcells MS, the better the light-sensing sensitivity, but as a whole, the number of microcells MS is increased as much as possible to increase the amount of light received. An area for drawing out the output wiring of each microcell MS is also required. In order to balance these demands, in the present embodiment, as shown in Fig. 17, the number of microcells MS arranged in the lateral direction Z (row direction) is increased in the longitudinal direction Y (column direction). doing more That is, a rectangular light sensing region R _act is formed. Accordingly, while securing the photosensitive region R _dead formed on both sides of the longitudinal direction Y in each light receiving pixel P _opt as the region of the output wiring pattern WPout , the microcell MS By increasing the number, the light reception amount can be increased while maintaining the light reception sensitivity, and the noise resistance is improved.

[Wiring Area]

For this reason, as the light-sensitive area R _dead , in the case of FIG. 17 , the light-sensitive area of the width W ₁ is located above and below the vertical direction Y of the light-sensing area occupied by the light-receiving pixel P _opt , In addition, a light-insensitive region having a width W ₂ is partially formed on each of the left and right in the lateral direction Z, thereby forming the photo-insensitive region. A light-insensitive region R _dead (which functions as a wiring region without a microcell) is formed by the upper, lower, left, and right photo-insensitive regions of this width W ₁ , W ₂ . When the scintillator block 143 is planarly viewed, on the lower surface 143L of the block, the light-sensing area of the light-receiving pixel P _opt extends in the lateral direction Z to form a horizontal rectangle. have. As the rectangle is formed, the number of microcells MS arranged inside the rectangle can sense a larger amount of light when arranged at the same interval. The degree of lateral extension is changed depending on the amount of light to be detected and the degree of light separation (noise).

In the pixel configuration of FIG. 17 , as shown in FIG. 15 , each light receiving pixel P _opt faces each detection pixel P _in through the optical interface 152 . In addition, it is preferable that the optical interface 152 is actually formed as an optically transmissive layer with a thin thickness of, for example, about 10 mu m.

For this reason, the fluorescence (pulsed faint light) excited by the X-ray photons in each scintillator 143A of the scintillator block 143 is emitted from the lower surface of each scintillator 143A (that is, each detection pixel P _in ). )) to the inside of the scintillator block 143 in all directions. Since a large portion of the side surface of each scintillator 143A is covered with a thin light-shielding material, the emission direction of fluorescence is limited to emission from the lower surface. A portion of the emitted fluorescence pulse is incident on the avalanche photodiode (APD) of each of the plurality of microcells (MS) of each light-receiving pixel (P _opt ). The incident fluorescence pulse is converted into an electric pulse signal by the photoelectric conversion function of the avalanche photodiode (APD) and the unset resistor (R). The converted electric pulse signal is output from each microcell MS through the electrostatic capacitance component C of the microcell MS. Since the plurality of microcells MS are wired-OR-connected to each other by a wiring pattern on the outside of the cell (refer to FIGS. 17 and 18), the OR connection from the plurality of microcells MS An electric pulse signal is taken out every time at least one microcell MS responds as one electric pulse signal.

In the present embodiment, the circuit for processing the output signal is constituted by a processing circuit 148 having a photon counting detection function, as shown in FIG. 18 to be described later. This processing circuit 148 is mounted on the ASIC block 144 in the present embodiment. This processing circuit 148 pays attention to the fact that each X-ray photon has a different energy, performs energy discrimination based on a plurality of predetermined energy regions, counts X-ray photons for each energy region, and based on the counted value, the target object It is comprised so that at least the kind and property of the substance contained in (P) can be classified, so-called substance identification can also be performed. Of course, it is also possible to obtain a so-called simple transmission image based on the coefficient values for each energy region.

The configuration of the energy discrimination function portion of the processing circuit 148 is known, for example, in International Patent Application Laid-Open No. WO2013/047788A1 or the like.

[Wiring Patterning]

In the present embodiment, a wiring connection from the aforementioned SiPM region R _SiPM to an input circuit portion and an input terminal in the processing circuit 148 to the ASIC region R _ASIC through the gap region R _space ; and an electrical connection between the ASIC region R _ASIC and the ASIC block 144 , and furthermore, an output signal from the ASIC region R _ASIC to the motherboard 44 . In addition to this, a method of employing a power supply line and a ground line between the above-described mother substrate 44 and the plurality of microcells MS existing in the SiPM region R _SiPM is also one of the characteristics.

As shown in FIG. 17 , the output lines of the plurality of microcells MS in each light receiving pixel P _opt are once wired or connected to each other in the vertical direction Y to form an upper vacant line. It is drawn out to the region above the empty region, that is, the photosensitive region R _dead , and the drawn out leader lines of each column are again drawn out in the lateral direction (Z) this time and wired or connected, and the light-receiving pixel is drawn out. It is collected at the output terminal (Tpixel) of each (P _opt ). That is, for each light-receiving pixel P _opt , the electric pulse signal output from the microcell MS in the pixel is taken out from this output terminal Tpixel.

One or a plurality of electric pulse signals collected at this output terminal (Tpixel) are transmitted through one output wiring pattern (line) (Wpout) running in the lateral direction (Z) in the upper region of the photosensitive region (R _dead ) through the ASIC The pad PD (refer to FIG. 12) formed for each pixel in the region R _ASIC is reached. Of course, it is formed by photolithography on the top surface US of the chip, including the circuit elements of the microcell MS itself, from this output line to the pad.

As shown in Fig. 17, if the above-described light-receiving pixel (P _opt ) is denoted as P _opt1 , the adjacent light-receiving pixel (P _opt2 ) in the lateral direction (Z) is similarly connected to the adjacent light-receiving pixel ( One output wiring pattern WPout from P _opt2 runs along the lateral direction Z and is electrically connected to a corresponding pad PDout formed in the ASIC region R _ASIC . Hereinafter, the same applies to the light-receiving pixel P _opt adjacent thereto in the lateral direction Z.

In addition, as shown in FIG. 17 , also for a plurality of light-receiving pixels (P _opt ) adjacent to each other in the lateral direction (Z) of the second stage, as in the first stage, the light-sensitive region (R _dead ) in the longitudinal direction (Y) It is drawn out through the output wiring pattern WPout up to the individual pads PDout in the lateral direction Z using the empty area above the . Hereinafter, although not illustrated in FIG. 17 , the same applies to a plurality of light-receiving pixels P _opt adjacent to each other in the lateral direction Z after the third step.

In addition, as can be seen from FIG. 17 , in the case of patterning the output wiring pattern WPout, the output wiring pattern WPout adjacent to the lateral direction Z, and the lower side thereof, that is, adjacent to the vertical direction Y, Between the horizontally adjacent output wiring patterns WPout, a partial region (region W ₁ ) of the photosensitive region R _dead is left without patterning. Thereby, mutual electromagnetic interference of the light-receiving pixels P _opt can be reduced, and it becomes easy to take mutual electromagnetic isolation.

Of course, this is determined in consideration of the wiring width, the number of wirings, the wiring density, and the like. The partial region (region of W ₁ ) may be used for the wiring pattern without leaving it.

As described above, the reason for taking out the output wiring pattern WPout from each light receiving pixel P _opt to one side in the lateral direction Z is that the ASIC block 144 is placed on one side of the lateral direction Z on the upper surface of the chip US ) because they are juxtaposed.

[ASIC area and pad placement]

In the ASIC region R _ASIC , pads (not shown) corresponding to the number of each light-receiving pixel P _opt are two-dimensionally arranged. The plurality of pads may be arranged in various ways, and this is also formed by photolithography.

The pad PD is located just below the ASIC block 144 to be mounted, and is aligned with the input terminal T _in (see FIG. 18 ) for a channel provided in the ASIC block 144 , have. The plurality of channels corresponds to the number of channels 148 ₁ to 148 _n for each pixel of the plurality of light-receiving pixels P _opt (the number of circuit parts from the preamplifier to the discrimination circuit).

These pads are for bump bonding, and are electrically connected to the input terminals T _in of the plurality of channels 148 ₁ to 148 _n of the ASIC block 144 by bump bonding (see enlarged portion of FIG. 12 ).

[ASIC block]

The ASIC block 144 is a device in which the processing units (that is, the processing circuit 148) for the plurality of channels 148 ₁ to 148 _n shown in FIG. 18 are integrated into an IC, and the external shape of the semiconductor chip 142 is in the longitudinal direction ( It is set to the same length as the length of Y), and a predetermined width in the lateral direction (Z) (see Fig. 12). In this case, in order to arrange the semiconductor chip 142, ie, the detection module 132, adjacent to each other in the longitudinal direction Y, such a dimension is set.

As the integrated processing circuit 148 inside this ASIC block 144, for each channel 148 ₁ (˜148 _n ) electrically connected to each input terminal T _in , as shown in FIG. 18 , the waveform A signal shaping circuit 161, a plurality of "n+1" comparators (where n is a positive integer of 2 or more) for setting a plurality of n energy BINs (ranges) in the X-ray energy spectrum 162 ₁ , 1162 ₂ , 62 ₃ , 162 ₄ ), and a counter 163 individually connected to these comparators 162 ₁ , 162 ₂ , 162 ₃ , 162 ₄ to count the number of X-ray photons having energy entering each energy BIN ₁ , 163 ₂ , 163 ₃ , 163 ₄ ).

Each waveform shaping circuit 161 is output from a plurality of microcells MS of each light-receiving pixel P _opt at the same time or with a constant timing difference, and is wired or added, through the output wiring pattern WPout and the bump bonding BD It is constituted by a circuit that performs calculus processing on one or more input electric pulse signals at regular intervals. Accordingly, one or a plurality of pulse signals are synthesized into one pulse signal by this calculus process, and the synthesized pulse signal is output at regular intervals. In the present embodiment, the SiPM 151 includes a plurality of small microcells MS, and the photoelectric conversion elements of those microcells MS, under application of an appropriate bias voltage, operate in a Geiger mode (Avalanche Photodiode (APD)). ), a signal is generated with a high gain of about 10 ⁶ due to the avalanche effect, and by discharging it with a value resistor, it becomes a pulse of 40 to 50 ns. When the scintillator material is GFAG, the output of the pixel is the synthesized output of each microcell depending on the delay time characteristics of the scintillator when the scintillator material is GFAG. can do it

The comparators 162 ₁ , 162 ₂ , 162 ₃ , and 162 ₄ are applied with reference voltages (thresholds) TH ₁ , TH ₂ , TH ₃ , and TH ₄ corresponding to the threshold values of the X-ray energy BIN. The reference voltages TH ₁ , TH ₂ , TH ₃ , and TH ₄ are voltage values corresponding to, for example, X-ray energy of 18 keV, 25 keV, 38 keV, and 50 keV (corresponding to tube voltage). Accordingly, three energy BINs of 18 to 25 keV, 25 to 38 keV, and 38 to 50 keV of the X-ray energy spectrum are arithmetically set. In addition, X-ray photons entering the energy range of 0-18 keV are excluded from the photon count as noise.

For this reason, the comparators 162 ₁ , 162 ₂ , 162 ₃ , and 162 ₄ , respectively, have peak values at their input terminals when they exceed the reference voltages TH ₁ , TH ₂ , TH ₃ , TH ₄ . When an electric pulse signal (an electric pulse signal synthesized for each light sensing element) of For this reason, the counter 163 ₁ (163 ₂ , 163 ₃ , 163 ₄ ) increments the count value in response to the output, thereby counting the number of X-ray photons.

In addition, in the integrated circuit inside the ASIC block 144, a count value recording circuit (Count Value Register) 164 and a count value reading circuit connected to the rear end of each counter 163 ₁ , 163 ₂ , 163 ₃ , 163 ₄ Count Value Read OUT Circuit) (165). The count value recording circuit 164 receives the count values from the respective counters 163 ₁ , 163 ₂ , 163 ₃ , 163 ₄ , calculates a photon count value for each energy BIN based on the mutual difference between the count values, and writes it to the internal memory once. do. This photon count value is read out at a constant timing for each light receiving pixel (that is, for each detection pixel) and every energy BIN by the count value reading circuit 165, and from a plurality of output terminals T _out as a digital signal of a predetermined number of bits. They are output sequentially in time series.

A plurality of output terminals T _out of this ASIC block 144 are returned to the ASIC region R _ASIC of the semiconductor chip 142 via another bump bonding, and input/output pads formed in the input/output pad region R _pad2 . (PD _ia ) is connected. This input/output pad PD _ia is formed by the chip upper surface US by the wiring pattern of the semiconductor chip 142 .

This input/output pad _PDia is electrically connected to the predetermined terminal of the mother board 44 by wire bonding WB, as shown typically in FIG. Via this predetermined terminal, digital data representing the photon count value of the X-ray detection device 22 is sent to the user PC: 27 via the front-end processor 26 .

The user PC: 27 performs substance identification and/or image generation based on such digital data, and provides the result to an X-ray non-destructive examination or a medical X-ray examination.

<Scan operation>

Next, based on FIG. 19, the scanning operation|movement of the X-ray inspection system 11 and its effect are demonstrated.

The flowchart shown in FIG. 19 explains the driving and control of each element, and image processing performed by the front-end processor 26 and the user PC cooperatively.

As shown in the figure, the user PC interactively sets shooting conditions with the user (step S11), and instructs the front-end processor 26 to adjust the X-ray detection device 22 . (Step S12).

Accordingly, the front-end processor 26 gives instructions to the drive units 24 and 43 to position the collimator 33 and the two length detectors 31 ₁ , 31 ₂ to their initial positions (step ( S13)). Accordingly, as shown in FIGS. 20 and 21 , the two elongation detectors 31 ₁ , 31 ₂ are discretely aligned to their predetermined initial positions ST1 , ST2 . In addition, initial position ST1, ST2 shall be determined in the state used as the left-end position of each of those detectors 31 ₁ and 31 ₂ is a left-most position.

At this time, the collimator 33 is also located at the initial position in the scan direction SD (actually, the inclination direction MD thereof). Accordingly, the X-rays irradiated from the X-ray generator 21 are collimated by the openings 33A and 33B of the collimator 33, are formed into two fan-beam X-rays, and are in the initial positions ST1 and ST2. It is irradiated only to the X-ray incident windows 31W ₁ , 31W ₂ of the detectors 31 ₁ , 31 ₂ , or only to the area made to have the above-mentioned predetermined margin than that.

Next, the front-end processor 26 gives a scan command according to a predetermined speed control profile (also referred to as a 'speed pattern') to the drive units 24 and 43 , the collimator 33 and the two elongation detectors 31 ₁ , 31 ₂ ) are started to move in the oblique direction MD (step S14 ). That is, the collimator 33 (openings 33A, 33B) and the detectors 31 ₁ , 31 ₂ are moved in the oblique direction MD in synchronization with each other. At this time, since the guide rail 42 is inclined by a predetermined angle θ with respect to the scan direction SD, the collimators 33 and the detectors 31 ₁ , 31 ₂ are synchronized with each other with respect to the scan direction SD. While being pulled up in the inclined direction MD by the angle θ, it moves along the scan direction SD.

This scan operation is performed from the initial positions ST1 and ST2 to the acceleration section (steering section) from the initial positions ST1 and ST2 until a stop position command by, for example, servo control of the driving devices 24 and 43 or a stop sensor provides stop position information. ), a constant speed section, and a deceleration section, followed by a trapezoidal-shaped speed control profile (steps S14 and S15: see FIGS. 20 and 21 ). That is, in the case of the example shown to these figures, one detector 31 ₁ makes the interval from the initial position ST1 to the position A1 reaching a constant speed an acceleration section, and deceleration starts from the position A1. The section to the position B1 to be made is the constant speed section, and the section from the deceleration start position B1 to the stop position SP1 is the deceleration section. The acceleration sections ST1 to A1 are also called slow start, and conversely, the deceleration sections B1 to SP1 are also called slow stops. Similarly, acceleration section ST2 to A2, constant speed section A2 to B2, and deceleration section B2 to SP2 are set also about the other detector 31 ₂ .

For this reason, about one detector 31 ₁ , position ST1-SP1 is scan charge range R1, and about the other detector 31 ₂ , position ST2-SP2 is scan charge range. (R2), and both scan coverage ranges R1 and R2 have an overlap section OV on the way. Based on the X-ray detection data in this overlap section OV, the X-ray detection data of both ranges R1 and R2 are connected, and the X-ray detection data for the imaging area 22W is digitized at a constant rate. of frame data can be created.

Upon completion of the scan operation (step S16), the front-end processor 26 issues a stop command and a return command to the drive units 24 and 43 to the drive units 24 and 43 (steps S16, S17). Next, while judging whether or not the next scan operation has been commanded, the same scan operation is repeated until the end (steps S18 and S19).

<Data collection, frame data generation, and action effects>

The front-end processor 26 performs the data collection and frame data generation processing shown in the right column of FIG. 19 as a post process or in real time or with a certain delay time in parallel with the above-described scan operation according to a predetermined procedure. do.

This collection and generation process is performed at a predetermined frame rate (eg, each of the detectors 31 ₁ , 31 ₂ ) output from the count value reading circuit 165 of the processing circuit 148 mounted in the X-ray detection device 22 . For example, the frame data FR _INI every 16000 fts is read and sequentially stored temporarily in the internal memory 22M (refer FIG. 22) (steps S31 and S32).

By this reading and temporary storage, the digital amount of X-ray photons counted from the pixel array Pay of each of the plurality of modules 132 arranged in a row in the internal memory 22M for each detector (that is, , a pixel value indicating the amount of X-rays for each pixel Pin) is saved. At this time, since there is a gap SP ₂ of a predetermined width that is a gap between the modules 132 , there is no pixel value in the corresponding position of the detector frame data FR _INI in the internal memory 22M ( FIG. 22 ). Reference).

Therefore, the front-end processor 26 adds, for example, the pixel value of each of the pixels Pines dividing the gap SP ₂ to the existing pixel value of the neighboring pixel by, for example, a known external insertion process. based on the estimation (step S33: see Fig. 22). For this reason, the length in the longitudinal direction Y of the gap SP ₂ , that is, the width of the gap is set according to the size of the pixel Pin (for example, 200, 250, 300 μm, etc.), Insertion operation becomes simpler. In this way, the detector frame data FR _DEC in which the value of the pixel of the gap SP ₂ is satisfied is stored in the memory 22M until the next process.

Incidentally, this external insertion process may be omitted.

Next, the front-end processor 26 converts the externally inserted detector frame data FR _DEC stored in the internal memory 22M to a reconstruction space Srec (pixel Prec) similarly constructed in the internal memory 22M. )), the sub-pixel method is performed while synthesizing the mapping pixels for a predetermined frame rate each collected from both detectors 31 ₁ , 31 ₂ by the shift-and-add method. , frame data corresponding to the photographing area 22W is generated (step S34: see Fig. 22). The frame data thus generated is saved in the internal memory 22M (step S35). This saved frame data is output to the user PC 27 upon completion of data collection and provided for image reconstruction, identification of material types based on the image, and the like (steps S36 and S37).

Here, the generation of frame data based on the shift & add method and the subpixel method performed in step S34, which can also be referred to as an oblique scan accompanying the movement in the oblique direction of the detector 31 according to the present application, is shown in FIG. 23 . describe it using

23 shows that, among frame data collected at, for example, a frame rate of 16000 fps, in a reconstruction space Srec having a pixel Prec of a predetermined size, sequentially collected at times t=t1, t2, t3, t4, and a gap ( The state in which the frame data supplemented with the pixel value was pasted one by one to SP2) is _shown . The sizes of the pixel Pin and the reconstruction pixel Prec, which are physical pixels, are, for example, the same as the above-mentioned 250×250 μm, and the number of pixels in the transverse direction Z (scan direction SD) of the detector 31 . is simplified to four and schematically shown. In addition, the predetermined angle θ is a value that moves by one pixel Pin in the longitudinal direction Y when the detector 31 moves by four pixels Pin in the scan direction SD, and have.

In addition, the sizes of the pixel Pin and the reconstruction pixel Prec may be different from each other.

In addition, since it is assumed that the detector 31 is moving at a constant speed (constant speed section) in the inclination direction MD of a predetermined angle θ, each time ( The amount of movement of frame data in t) is constant. That is, in the speed control profile shown in FIG. 20, mapping (attached) of frame data is shown according to the movement amount synchronized with the speed in the sections of constant speed sections A1 to B1 and A2 to B2.

As described above, according to the present embodiment, for this reason, the frame data for the entire detection data of the module columnar body 132M in which the pixel values of the gap SP ₂ portion of the detector 31 are supplemented by external insertion are stored in the reconstruction space ( Srec) is sequentially mapped in the inclination direction of a predetermined angle θ. At this time, although the pixel value is supplemented, the gap SP ₂ part which is not direct detection data also inclines (shifts) at a predetermined angle (theta).

Therefore, the front-end processor 26, for each reconstruction pixel Prec of the reconstruction space Prec, based on the pixel value and the area contributed by the pixel Pin of each frame, based on the so-called sub-pixel method, The pixel value of the reconstruction pixel Prec is calculated. For example, paying attention to the pixel Prec-n near the center of FIG. 23 , the reconstructed pixel Prec is an externally inserted pixel as a part of the pixel in the pixel portion Pa (gap SP ₂ ) portion. value), the pixel portion Pb (part of the pixel at time t=t4), the pixel portion Pc (part of the pixel at time t=t3), and the pixel portion Pd (of the pixel at time t=t2) part) is composed of For this reason, the pixel values of the reconstructed pixels Prec-n are calculated by adding them according to the area of the pixel portion (here, an area corresponding to 1/4 of the total area of the pixel).

Incidentally, when the above-described external insertion processing is omitted, the pixel portion Pa does not exist, and even if the pixel values of the pixels Prec-n are determined from the pixel values and areas of the pixel portions Pb, Pc, and Pd. free of charge

The other reconstruction pixels Prec are also the same. In particular, the pixel values are similarly calculated in the overlap section OV of the scan ranges R1 and R2 shared by the two detectors 31 . However, in this overlap period OV, if there is a pixel that both detectors 31 detect, the pixel values are averaged and provided by the sub-pixel method. From the viewpoint of reducing this averaging operation, in the speed control profile in FIG. 20 , B1 = A2, that is, the end point of the constant speed section of one detector 31 ₁ and the start point of the constant speed section of the other detector 31 ₂ . It is preferable to match

In addition, the front-end processor 26 maps the frame data and executes the subpixel method as described above, during or after the execution, the acceleration sections ST1 to A1 of one detector 31 ₁ , the other The deceleration section B2 to AP2 of the detector 31 ₂ of the detector 31 1 forms a triangle at the upper and lower ends in the longitudinal direction Y of the detector 31 ₁ , and the detector inclination movement parts DP1 and DP3, and the other detector ( 31 ₂ ), the pixel data of the detector tilting portions DP3 and DP4 in the upper and lower ends in the longitudinal direction Y are discarded.

Accordingly, as shown in FIG. 21 , a spherical image area IMarea based on the scanning operation of both detectors 31 is provided inside the imaging area 22W. The frame data of this image area IMarea includes data of an acceleration section and a deceleration section at both ends in the scan direction SD, and data of an unstable triangular part due to lack of data at the upper and lower ends accompanying the inclination movement of the detector 31. It becomes the excluded, stable and reliable data. This frame data is sent to the user PC 27 .

<Ninth arrangement example>

Here, the arrangement example of the three-sided bubble of the above-mentioned elongate detector is demonstrated as a 9th arrangement example using FIG.

As shown in FIG. 24 , the X-ray detection device 22H according to this arrangement is equipped with two elongated detectors 31 ₁ , 31 ₂ , and the two elongated detectors 31 ₁ are mounted thereon. , 31 ₂ ) are disposed adjacent to each other with their backs facing each other at the left end in the scan direction SD of the imaging area 22W. That is, one elongate detector 31 ₁ is disposed on the front side of the advancing direction in the scan direction SD, and the other elongate detector 31 ₂ is disposed behind the advancing direction of the scan direction SD. , both spherical X-ray incidence windows 31W ₁ , 31W ₂ of both detectors 31 ₁ , 31 ₂ are arranged along the longitudinal direction Y (first direction) and adjacent to each other. . That is, the direction of the longitudinal direction Y with respect to the other detector 31 ₁ of the other elongate detector 31 ₂ is reversed.

The gap between the two X-ray incident windows 31W ₁ , 31W ₂ is preferably set to 0 as much as possible, but in manufacturing, for example, a certain gap SP ₃ (for example, a gap corresponding to before and after one pixel) ), it is also free to empty.

Moreover, as a characteristic arrangement structure, both detectors 31 ₁ , 31 ₂ are made different from each other by a predetermined distance D in such a longitudinal direction Y. This predetermined distance D is a length corresponding to a pixel of D=0.5+N (N is a positive integer equal to or greater than 1). For this reason, D = 1.5 pixels, 2.5 pixels, ... , and is set to a length that is easy to process with respect to the size of the pixel. Of course, the predetermined distance D may be a length equivalent to 0.5 pixels.

By setting the two elongated detectors 31 ₁ and 31 ₂ in a three-sided bubble arrangement in this way, their X-ray incident windows 31W ₁ , 31W ₂ can be adjacent to each other with at least a certain gap SP ₃ . have. That is, compared to a single elongated detector, the length of the X-ray incident window in the scan direction SD, that is, the length of the opening receiving X-rays, can be increased, and the detection function of the two-dimensional surface detector can be more closely approached.

The two elongation detectors 31 ₁ , 31 ₂ are tilted by a predetermined angle θ with respect to the scan direction SD while maintaining a difference of a predetermined distance D in the longitudinal direction Y. MD), it is possible to scan with a wider X-ray incident window 31W ₁ +31W ₂ . Thereby, by moving obliquely as mentioned above, the super-resolution effect can be acquired more effectively.

In addition, a correction process is performed similarly to the correction| _amendment with respect to the gap SP2 of the longitudinal direction Y mentioned above also about the case where a pixel does not exist in the fixed gap|interval SP ₃ in the scan direction SD.

<Effect>

As mentioned above, the X-ray inspection system 11 which concerns on this embodiment, and the scanning type X-ray detection apparatus 22 mounted on this were demonstrated with various detector arrangement examples. According to this embodiment, especially, the effect of the structure which the present inventors call "multi-row arrangement|positioning" which arrange|positions a plurality of elongation detectors discretely along the longitudinal direction Y, and one or a plurality of The inventors of the present invention move the elongate detector obliquely by a predetermined angle [theta] from the scan direction SD, which can be broadly divided into the effect of "mechanical tilt scan". Of course, as described above, by performing a combination of multi-row arrangement and mechanical oblique scan, the effects of both can be obtained.

<Multi-row arrangement>

When multi-row arrangement|positioning is employ|adopted, first, one imaging|photography area|region 22W can be divided and scanned by the two elongate detectors 31 ₁ , 31 ₂ , for example. Accordingly, compared to the case of scanning one detector, the scanning time, that is, the imaging time required for data collection can be shortened by 1/several minutes.

In addition, the area of the partial regions DP1 to DP4 to be discarded at the time of frame data generation described with reference to FIG. 21 is smaller than that in the case of performing the conventional oblique scan with one elongate detector by setting the multi-row arrangement. For this reason, the collected data can be used as much as possible without waste.

<Mechanical tilt scan>

In addition, in the case of the mechanical oblique scan, each elongate detector 31 has a gap SP ₂ between the modules 132 adjacent to each other, so even when there is no physical detection pixel, pixels corresponding to the gap SP ₂ . After the values are interpolated by external insertion, they are obliquely affixed to the reconstruction space Prec (see Fig. 23). For this reason, there is no effect due to the absence of a detection pixel in the gap SP ₂ , and even if the gap SP ₂ exists by mapping in a relative inclination direction with the reconstruction space Prec, the pixels are displayed with high resolution. It is possible to reconstruct frame data made up of digital non-digital pixels (Prec) with smooth changes. In addition, since the scan at an angle reduces the statistical noise, the statistical noise is reduced compared to the reconstructed pixel size. That is, the exposure dose is reduced.

By organically linking these superiorities with each other, so-called substance identification, which classifies types and properties of substances in objects that can be photographed by the user PC, becomes more accurate and reliable.

In this way, the module columnar body 132M, that is, the elongation detector 31 can be manufactured in a state where the presence of the known gap SP ₂ at regular intervals is allowed. That is, the constraint that the plurality of modules 132 be adjacent to each other without gaps is relieved or eliminated, thereby facilitating the assembly operation and reducing the assembly cost.

In addition, since the frame data of the detector is pasted in the reconstruction space in the process of generating the image data of the image area IMarea, it is also possible to restore the resolution having a pixel smaller than the detection pixel. In addition, it is possible to reduce mixing of scattered rays from a subject (object) compared to a surface detector.

<Multi-row batch, mechanical scan>

In addition, in the case of a mechanical oblique scan on the premise of this multi-row arrangement, as described in FIG. 21 , in the imaging area 22W, which is the sum of the scan sharing areas R1 and R2, in fact, the detected data changes in the scan speed ( Acceleration/deceleration) and data of the image area (IMarea) are obtained by excluding the unstable partial area of the pixel value. For this reason, it is possible to more stably obtain only data in a high-resolution area, and to achieve higher quality of the reconstructed image.

In addition, in the present embodiment, the length and width of the openings 33A and 33B (or one of them) formed in the collimator 33 can be made smaller in both the multi-row arrangement and the mechanical scan. That is, as shown in Fig. 21, the finally requested collection area is the illustrated image area IMarea. Since each detector 31 has an X-ray incident window 31W, the width Wc of the incident window 31W is determined, but the length Hc in the longitudinal direction Y is the same as that of the image area IMarea. The length in the longitudinal direction has to be satisfied. For this reason, the vertical and horizontal widths of the openings 33A and 33B have a spherical shape of length Hc × width Wc, which is a part of the image area IMarea, or have the above-mentioned predetermined margin. What is necessary is just to be able to collimate X-rays on a spherical shape. When collimating with the size of this length (Hc) x width (Wc), it is smaller than the conventional oblique scan (for example, the scan structure described in WO2017/170408A1 described above) of the same size in which the detector itself is arranged at an angle. and thus contributes to the reduction of X-ray exposure to the subject.

<Operational Effects of Photon Counting Type and Scanning Type Detector>

The elongate detector 31 according to the above embodiment is a photon counting detector that counts the number of photons as the amount of X-rays, and is a scanning detector that operates as a surface detector while scanning an object.

Accordingly, compared to the conventional integral type X-ray detector, the reduction of mixing of the scattering component from the patient by discretely disposing the detector is reduced, compared to the original, the bokeh corresponding to the light diffusion of the scintillator is reduced. Since it is small, the resolution is excellent; the contrast resolution is high because the mixing of electric noise can be reduced; In addition, some have high detector sensitivity. Moreover, since the process up to the X-ray pulse signal processing can be accelerated, a high-speed response is also possible. In addition, since it is a photon counting type, energy information of transmitted X-rays can be discriminated and processed with high precision, so it is suitable for processing dependent on energy discrimination, such as so-called substance identification. Furthermore, it is possible to significantly reduce the X-ray exposure dose to the doctor as well as the patient, which is a problem these days in the medical diagnostic apparatus. This is due to high detection sensitivity and low electrical noise.

On the other hand, compared to a direct conversion type X-ray detector using a semiconductor such as CdTe, the elongated detector 31 of the present application has a wide detectable energy range (keV), a high detection sensitivity, and a pixel Since there is little crosstalk (corresponding to charge sharing) between livers, energy drawing ability is high, and as a result, it is excellent in a count rate characteristic (1% count loss/1mm< ² >). Accordingly, the application range of this detector is wider. In addition, since there are fewer unstable factors such as polarization, it is possible to cope with the detection capability required for medical CT, food foreign material inspection, and the like. Furthermore, it is unnecessary to supply a high bias voltage necessary for the operation of the CdTe semiconductor, and it is possible to facilitate the circuit design of the detector, thereby making it easier to respond to medical safety standards. Of course, it is also possible to suppress the manufacturing cost to a lower level.

In addition, by using the scan type, mixing of scattered rays from the object is extremely reduced, the image quality (contrast resolution) is improved, and when the detection configuration of the photon counting type is adopted, it also contributes to the improvement of the accuracy of material identification. In particular, since synchronous interlocking with the collimator 33 is used in combination, the X-ray irradiation field is collimated to the width of the X-ray incident window 31W required for the moving elongated detector 31, and in the longitudinal direction. The length of (Y) is collimated by the length Hc shown in FIG. 21 or the length which added a fixed margin to it in this embodiment. Accordingly, the X-ray exposure dose is further reduced. Collimation of the irradiation field to the length Hc in the longitudinal direction Y is only possible with the mechanical scan according to the present embodiment, and is one of the advantages over the conventional scanning type in which the detector itself is tilted at an angle.

[Second embodiment]

Next, 11 A of X-ray inspection systems which concern on 2nd Embodiment are demonstrated based on FIGS.

In addition, also in this embodiment, the same code|symbol is attached|subjected to the element which exhibits the same or equivalent function as the element demonstrated by the above-mentioned Example and various arrangement example, and the description is abbreviate|omitted or simplified.

This X-ray inspection system 11A is a detector in which the three elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) according to the third arrangement example (see FIG. 5 ) or the fourth arrangement example described above are further developed. have a structure Of course, although the number of the elongation detectors 31 also depends on the size and structure of the inspection object OB, 4 or 5 or more may be sufficient.

Described as a preferred example, based on the three elongated detectors 31 ₁ , 31 ₂ , 31 ₃ according to the third arrangement example shown in FIG. 5 , this detector arrangement structure is used in a medical examination system, in particular, publicly, It is applied to a scan-type medical examination system for chest imaging. This medical inspection system is a flat panel detector (FPD) in terms of a product group that has been put into practical use. In this embodiment, of course, it is comprised as an X-ray inspection system which can follow the characteristics of the photon counting and a unique scanning method mentioned above as it is.

In the present embodiment, in addition to these characteristics, a plurality of elongated detectors (preferably two or more elongated detectors) perform a shared scan in each scan direction, and in the imaging area 22W (refer to FIG. 2 ) covering the entirety, As the sagittal difference during the start and end of the scan (the maximum value of the time difference depending on the detection position of data collection), it is said that it is suitable for imaging in which a region that requires a locally smaller sagittal difference is included. Of course, if the plurality of elongated detectors can be moved at a higher speed to ensure the minimum sagittal difference required for imaging of a local area, the scan structure described below need not be employed. However, while the entire imaging area 22W is scanned, there is an object or an imaging target for which such a shorter sagittal difference is required locally.

As an example, there is a chest diagnosis in a medical examination, for example. When examining the chest, since the lungs and heart are in motion, it is preferable that the sagittal difference between the start and end of the scan be smaller. In particular, the heartbeat usually moves with a smaller cycle than that of the lungs. For this reason, in chest imaging, the cardiac region is an imaging target site that requires a shorter sagittal difference locally as such.

For this reason, the X-ray examination system 11A concerning this embodiment is comprised so that it can mount in the medical diagnostic apparatus which can perform chest imaging in consideration of the state in which the heartbeat moves faster than other parts (lungs, etc.).

The outline of the X-ray examination system 11A in which chest imaging is possible in FIG. 25 is shown. This X-ray examination system 11A is equipped with the X-ray detection apparatus 22H which considered such a heartbeat. This X-ray detection device 22H employs three elongate detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) according to the third arrangement example shown in FIG. 5 , and furthermore, the above-described heart movement (local It has a configuration in which an additional elongated detector configured to be tracked in terms of sagittal difference in data collection is added to the target region (a region that moves faster than other regions).

Other configurations are the same as or equivalent to those of the first embodiment according to the third arrangement example except for the collimator 133 . About the collimator 133, from a viewpoint of reduction of manufacturing cost and X-ray exposure, this embodiment employ|adopts the compromise structure so that it may mention later.

The arrangement structure of the elongate detector of the X-ray detection apparatus 22H in FIG. 26 is demonstrated. This X-ray detection apparatus 22H schematically shows and shows the X-ray flat panel detector (FPD) for chest imaging of 14 inches x 17 inches as an example.

As shown in FIG. 26 , this X-ray detection device 22H includes three first elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) and a body of the elongated detector 31 . and three second elongated detectors 231 ( 231 ₁ , 231 ₂ , 231 ₃ ) configured to be movable integrally with each other. The three first elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) all have the same length and the same width, and have a configuration equivalent to that according to the third arrangement example described above. On the other hand, the three second elongate detectors 231 ( 231 ₁ , 231 ₂ , 231 ₃ ) are respectively formed to have a length in the longitudinal direction Y shorter than that of the first elongate detector 31 in the arranged state. has been This shortness is set to a length capable of covering the range in the height direction of the heart region HT of the standard size located in the lower central portion of the chest field of view, assuming that the entire imaging region 22W covers the chest. has been Incidentally, the second thin detectors 231 ( 231 ₁ , 231 ₂ , 231 ₃ ) all have the same length and the same width in the present embodiment, but they may be different from each other.

More specifically, in the present embodiment, as shown in FIG. 27 , the three first thin detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) have the same size and structure as described above. In contrast, the three second thin detectors 231 ( 231 ₁ , 231 ₂ , 231 ₃ ) cooperate with the first thin detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) to capture the entire chest area. Among 22W, it is arrange|positioned so that it may cover the local area|region including the area|region (heart area|region HT) which image|photographs a heart. The first and second elongation detectors 31 and 231 are respectively mounted on independent mother substrates 441 , and these six mother substrates 441 are arranged on the upper surface of the common support 451 . This support 451 is driven by the drive device 431 along the guide rail 421 arranged obliquely by a predetermined angle θ with respect to the scan direction SD, and thus performs an inclined scan similar to that described above. It is designed to be able to This configuration is the same as the configuration described in Fig. 3 described above, in which an oblique scan can be performed with two elongated detectors.

More specifically, as an example, the first thin detector 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) is configured to include an imaging area 22W (eg, They are discretely arranged at a predetermined interval Z1 (eg, 118.2 mm) in the lateral direction (Z-axis direction) in length: 428.75 mm × width: 354.60 mm). The first elongate detector 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) has a predetermined length Y1 (eg, 428.75 mm) in the longitudinal direction (Y-axis direction), respectively, and includes the module 132 described above. (An example of a vertical/horizontal size is 6.25 mm x 4 mm), for example, 66 pieces, are arrange|positioned adjacently in a _row , and set the gap SP2 (for example, 0.25 mm).

In contrast, the second elongation detectors 231 ( 231 ₁ , 231 ₂ , 231 ₃ ) are all formed with the same length and the same width, and are formed at a predetermined interval Z2 in the lateral direction (Z-axis direction) (for example, 39.4mm) and placed discreetly. However, in the present embodiment, on the right side of FIG. 26 , the detectors covering the lower predetermined length Y2 (eg, 214.38 mm) of each of the two first elongated detectors 31 ( 31 ₂ , 31 ₃ ) The portions 31 ₂₂ , 31 ₃₂ (refer to the hatched portions in FIG. 26 ) serve not only as the first thin detector part but also as the second thin detector. The predetermined length Y2 is set to Y2<Y1.

For this reason, in the case of this embodiment, the number of the 2nd thin detectors 5 including the said combined part 31 ₂₂ and 31 ₃₂ are arrange|positioned at the predetermined space|interval Z2 (for example, 39.4 mm). That is, five _second thin detectors 231 ₁ , _{31 22} , 231 ₂ , _{31 32} , 231 ₃ , including some useful parts, are more transverse ( Z-axis direction), more densely arranged.

This X-ray examination system 11A operates an X-ray chest imaging apparatus, for example. In this case, that is, the X-ray detection apparatus 22H can function as a scanning type FPD. The imaging area 22W of the X-ray detection device 22H covers the entire chest of the subject. For this reason, when the drive device 431 of the X-ray inspection system 11A is driven to diagonally scan the X-ray detection device 22H, the three first elongated detectors 31 ( 31 ₁ , 31 ₂ , 31 ₃ ) are , captures the imaging area 22W covering the entire chest at the speed V1 (eg, 0.15 sec) by the above-mentioned divided scan in 3 equal parts and the oblique scan. Of course, this speed V1 changes depending on the driving conditions.

In complete sagittal parallel to this oblique scan, the five second elongated detectors 231 ₁ , 31 ₂₂ , 231 ₂ , 31 ₃₂ , 231 ₃ including the functional detector part described above are also divided into 5 equal division scans (Fig. Reference numerals 26 and 27 (B1 to B5)) and by oblique scan (refer to arrow MD in FIG. 27 ), the heart region, which is a local part, of the imaging region 22W of the entire chest is imaged. At this time, since the mounting density in the lateral direction (Z) of the detector is three times the scan speed at this time, the scan sharing range of each of the second elongated detectors 231 ₁ , 31 ₂₂ , 231 ₂ , 31 ₃₂ , 231 ₃ is 1 It is scanned at a velocity V2 (eg, 0.05 sec), which becomes /3. That is, the heart region is photographed at 1/3 the scan rate compared to the rest of the region.

Incidentally, the collimator 133 cooperates with the first and second elongation detectors (that is, the mother substrate 441) of the X-ray detection device 22H by the front-end processor 26 in the above-described inclination movement direction. (MD) is moved accordingly. The collimator 133 includes three first thin detectors 31 (31 ₁ , 31 ₂ , 31 ₃ : partly, also serves as a second thin detector)) and three second thin detectors 231 (231 ₁ , 231 ). ₂ , 231 ₃ )) corresponding to the first to sixth slits 133A to 133F are formed in parallel to each other and discretely.

Accordingly, the X-rays incident on the share range B1 to B5 that is the share of the second thin detector 231 ₁ , 31 ₂₂ , 231 ₂ , 31 ₃₂ , 231 ₃ including the functional detector portion described above are , at least collimate, and X-ray exposure is reduced.

In the present embodiment, the output data of the entire detection module 132 collected by scan shooting is once mapped to a reconstruction space on the memory of the user PC 27 and reconstructed according to, for example, the sub-pixel method, similarly to the above. and is provided as a chest image. In addition, when collecting this data, for the second thin detectors 231 ₁ , 31 ₂₂ , 231 ₂ , 31 ₃₂ , 231 ₃ including the functional detector part described above, the processing circuit determines their division range ( It is configured so that only the data of B1 to B5) is employed. That is, for each detector, it is comprised so that the data collected in the range other than each sharing range B1 (-B5) may be ignored.

As described above, in the case of chest imaging, since the effect of data collection of heart movement on the thalamus is greater than that of the lung field, in the case of scan-type FPD, from the start to the end of scanning the heart region. It is preferable to suppress the sagittal difference to about 0.05 seconds. According to this embodiment, this request|requirement can be met.

In addition, the structure demonstrated in the said 1st Embodiment and various detector arrangement examples, for example, the structure of a detector, predetermined angle (theta) of an oblique scan, etc. can be employ|adopted similarly also in this 2nd Embodiment.

For this reason, when the characteristic of this embodiment is summarized, it becomes as follows.

In addition to the plurality of first elongation detectors 31 , a plurality of second elongation detectors 231 , local parts of the imaging area 22W of the plurality of first elongation detectors 31 , in the plane of sagittal difference They are arranged so that they can be detected more precisely. Moreover, both the first and second elongation detectors 31 and 231 are integrally moved for scanning, for example, in the above-described oblique direction MD. For this reason, while the second thin detector 231 also enjoys the above-described effects, it is possible to reduce the lag difference due to the difference in the scan positions of data collection compared to the first thin detector 31 . For example, under a certain scan condition, the time difference between the scan start and the scan end of each of the plurality of first elongated detectors is 0.15 second. At this time, the mounting density of the plurality of second thin detectors 231 in the second direction (transverse direction) (however, functionally, some parts 31 ₂₂ , 31 ₃₂ of the first thin detector 31 are included) The second elongation detector 231 can be arranged so as to be, for example, three times larger than that of the plurality of first elongation detectors 31 and to cover a necessary local area of the entire imaging area 22W. Accordingly, the time difference between the scan start and scan end of each of the plurality of second thin detectors can be shortened as in the above example. This can meet the needs demanded in the clinical setting, for example in chest X-rays of humans.

In addition, since the plurality of second elongated detectors 231 are shorter than the plurality of first elongated detectors 31 all having the same length in the first direction, the second elongated detectors 231 are used in the entire imaging area 22W. ), the degree of freedom of arrangement for which part to cover is high. For example, in such a partial area with a high density of detection, the characteristics of the object to be photographed, such as the upper part or the central portion of the entire imaging area 22W (localized part inside, or the part moving faster than the whole) It can be suitably changed depending on what you do, etc.).

In addition, a portion of the plurality of first elongation detectors 31 also employs a configuration in which the second elongation detector 231 is also used in the first direction. Thereby, the number of the 1st and 2nd thin detectors can be suppressed to a necessary minimum, the complexity of a structure can also be suppressed, and an unnecessary increase in component cost can also be avoided.

In addition, the feature according to the second embodiment can be said to be a detector capable of selectively shortening the photographing time of only a specific area. In addition, it can be said that both an image in which time is lengthened only in a specific area and an image photographed in a fraction of the time can be acquired. This can also be used to verify whether the photographed part has moved while photographing, if all the acquired data is used without discarding it. From this point of view, the plurality of second thin detectors may be arranged to be movable manually or automatically in a direction orthogonal to the scan, and the photographing position of a selective specific area may be changed.

In addition, in the case of 2nd Embodiment, although the 3rd arrangement example (FIG. 5) was employ|adopted as the arrangement example of the 1st, 2nd elongate detector, you may employ|adopt the 4th arrangement example (FIG. 6) instead of this. In the case of this fourth arrangement example, both the first and second elongation detectors 31 and 231 are integrally formed and maintained in alignment along the first direction (longitudinal direction), while maintaining the alignment in the second direction (short direction, width direction). direction, transverse). In the case of this aspect, the process of employing the pixel signal dropout due to the gap SP ₂ between modules, for example, employing an average value using the pixel signals in the vicinity thereof, is required. This is also as described above.

Further, the number of the first thin detectors is one or more, but it is preferred that it is an aspect in which two or more thin detectors are preferably scanned. The number of the second thin detectors may increase the mounting density of the first thin detectors in the scan direction. Such a number can be determined according to the nature of the object to be photographed.

By the way, in the second embodiment, a portion having a high detector mounting density (covering the heart region) is locally set in the lower central portion of the entire imaging region 22W (covering the chest region). A portion including the parts 31 ₂₂ , 31 ₃₂ was also configured as a second thin field detector. That is, the portion having a high mounting density is dividedly scanned by the five short second thin detectors 231 ₁ , 31 ₂₂ , 231 ₂ , 31 ₃₂ , 231 ₃ , and the spherical second local area is formed. succeeded). However, the plurality of first elongate detectors are treated as they are, and a second short elongate detector is disposed complementary between the detectors of the plurality of first elongated detectors so that, for example, a local region such as a heart region is shared by both. You might think of it as Mars. That is, it is not necessary to consider that a part of the first thin detector also serves as the second thin detector.

In addition, this invention is not limited to the structure of the above-mentioned embodiment, As long as it does not deviate from the summary of this invention, you may implement combining further various structures.

11, 11A: X-ray inspection system (radiation inspection system)
21: X-ray generator
22, 22A to 22G, 22H: X-ray detection device (radiation detection device)
22W: shooting area
23, 24: drive device (mobile means)
25: drive device (mobile means)
26: Front-end processor (vehicle)
27: User PC
31: first slender detector (X-ray detector)
231: second thin field detector
31 ₂₂ , 31 ₃₂ : a part of the first thin detector and a part of the detector useful as the second thin detector
31W: X-ray incident window
31L: Long side (providing first direction)
31S: Short side (provides a second direction)
33, 133: collimator
33A, 33B: first and second slits
133A to 133F: first to sixth slits
42, 421: guide rail (mobile means)
43, 431: drive device (moving means)
44, 441: mother board (detector support)
45, 451: support frame (support, detector support)
132M: module column
PXay: Pixel Array
131: case
132: module
SP ₂ : Gap (gap, gap)
Y: Long direction
Z: short direction
θ: predetermined angle
MD: oblique direction
IMarea: image area
OB: Inspection object
R1, R2, R3: scan range by the first thin detector (scan share range)
B1, B2, B3, B4, B5: Scan range by the second thin detector (scan share range)
XB: X-ray fan beam (X-ray, radiation)

Claims (26)

A module column body in which a plurality of modules having a pixel arrangement in which pixels for detecting radiation are arranged two-dimensionally in a first direction and a second direction orthogonal to each other are arranged adjacent to each other in the first direction through a gap of a predetermined width , wherein the module column has a long side along the first direction and a short side along the second direction, and the long side is longer than the short side, and has an elongated spherical shape in plan view. A thin field detector formed of
The elongated detector is supported in a posture in which the second direction is directed to the scanning direction and the first direction is directed to a direction orthogonal to the scanning direction, and is moved in an oblique direction forming a predetermined angle with respect to the scanning direction. a detector support capable of supporting;
Moving means for moving the elongated detector in the oblique direction according to a scan command during imaging to which the radiation is irradiated
A radiation detection device comprising a. According to claim 1,
The pixel arrangement is a pixel arrangement along rows and columns in the first direction on a two-dimensional plane formed in the first and second directions,
The elongation detector includes a plurality of elongation detectors arranged apart from each other in the second direction, and each of which is supported movably in the scan direction by the detector support portion;
and each of the plurality of elongated detectors is arranged to share a scan range up to a movement start position of another adjacent elongate detector in the scan direction in response to the scan command. 3. The method of claim 2,
The detector support part,
Each of the plurality of elongated detectors is arranged to be spaced apart from each other by the same distance in the scan direction, and a movement distance in the scan direction accompanying the scan command is configured to be equal to each other. 4. The method of claim 2 or 3,
The plurality of elongated detectors are two, A radiation detection apparatus characterized in that. 4. The method of claim 2 or 3,
The plurality of elongated detectors are three, the radiation detection apparatus. 6. The method according to any one of claims 1 to 5,
The means of movement is
Moving means for moving the plurality of elongated detectors in synchronization with each other in the oblique direction in accordance with the scan command at the time of imaging to which the radiation is irradiated
A radiation detection device comprising a. 7. The method according to any one of claims 2 to 6,
The detector support part,
and a base body for integrally supporting the plurality of elongated detectors;
The means of movement is
a driving mechanism capable of moving the base body in the oblique direction in response to the scan command;
Movement control means for controlling the driving of the drive mechanism to move the base body in the oblique direction by at least a distance covering the scan sharing range covered by each of the plurality of elongated detectors in the second direction
A radiation detection device comprising a. 8. The method of claim 7,
The scan sharing range covered by each of the plurality of elongated detectors is,
The radiation detection device, characterized in that they are identical to each other in the second direction. 9. The method according to claim 7 or 8,
The movement control means,
The radiation detection apparatus of claim 1, wherein each of the plurality of elongated detectors is configured to move at a constant velocity the distance in the second direction corresponding to at least the scan sharing range of each of the detectors. 10. The method of claim 9,
As a speed control profile of the movement of each of the plurality of elongated detectors, an acceleration range from the movement start position of each of the detectors to transition to the constant velocity movement, a constant velocity movement range in which the constant velocity movement is performed, and the constant velocity movement With a deceleration range from the range to the stop position,
The movement control means,
and move the detector support in the oblique direction according to the speed control profile. 11. The method of claim 10,
The speed control profile is
of the plurality of elongated detectors, the deceleration ranges of the second and subsequent elongated detectors in the scan direction and the acceleration ranges of the third and subsequent elongated detectors in the scan direction are set to overlap each other on the speed control profile A radiation detection device, characterized in that. 11. The method of claim 10,
of the plurality of elongation detectors, the plurality of elongation detectors excluding the acceleration range of the first elongation detector and the deceleration range of the last elongation detector in the scan direction corresponding to the scan direction, A radiation detection apparatus configured to set a two-dimensional range in which the first and second directions are orthogonal axes that move in two directions and form as an imaging area by scanning the radiation. 3. The method of claim 2,
The plurality of elongation detectors includes a plurality of first elongation detectors and a plurality of second elongation detectors having different lengths of the module columns,
a detector support for integrally supporting the plurality of first elongation detectors and the plurality of second elongation detectors;
Moving means for moving the detector support in the inclined direction at a constant speed when scanning by the radiation
equipped with,
The detector support part,
The range of a part of the imaging area by the radiation covered by the plurality of first elongated detectors being scanned by the plurality of first elongated detectors while supporting each other discretely at a first separation distance in the second direction. a second separation distance shorter than the first separation distance in the second direction together with a portion of the second direction of some of the first thin detectors of the plurality of first elongation detectors, the plurality of second elongation A radiation detection device, characterized in that configured to support the detectors mutually discretely. 14. The method of claim 13,
The number of the plurality of second elongated detectors is greater than the number of the first elongated detectors, and the plurality of second elongated detectors includes elongated detectors having the same arrangement position in the second direction. which is a radiation detection device. 15. The method of claim 13 or 14,
The pixel arrangement is a pixel arrangement along rows and columns in the first direction on a two-dimensional plane formed in the first and second directions,
The detector support part,
movably supporting each of the plurality of first elongated detectors to a movement start position of an adjacent first elongated detector in the scan direction in response to the scan command;
Each of the plurality of second elongation detectors is configured to movably support a movement start position of an adjacent first or second elongate detector in the scan direction in response to the scan command. , radiation detection device. 16. The method according to any one of claims 13 to 15,
the plurality of first elongated detectors are three;
the plurality of second elongation detectors are five arranged to take charge of the scanning of the partial area of the imaging area;
The partial area of the photographing area,
In the imaging area, the scan size and position of the target site for which a lag in data collection by the scan is required to be smaller than that of the remaining areas other than the partial area are set to be scannable,
A radiation detection device, characterized in that. 17. The method according to any one of claims 1 to 16,
The predetermined angle is
Among the plurality of pixels arranged in the respective modules of the elongated detector, the distance indicated by the plurality of pixels arranged in the second direction: (A1) and the width of the gap in the first direction: (A2) It is set based on rain, The radiation detection apparatus characterized by the above-mentioned. 18. The method of claim 17,
The predetermined angle: (θ) is,
Based on the distance: (A1), the width: (A2), and the number (n) of the pixels (where n is a positive integer excluding 0) assuming that the pixels are arranged in the gap,
θ≥tan ^-1 n·(A2/A1)
A radiation detection device, characterized in that it is set by. 19. The method of claim 17 or 18,
When the length of each pixel in the first direction is b,
wherein the width: (A2) adopts a value of b=(1/2)b to 2b. 20. The method according to any one of claims 1 to 19,
The radiation detection device, characterized in that the X-ray. 20. The method according to any one of claims 1 to 19,
The plurality of elongated detectors are each a detector provided with a photon counting type processing circuit that counts the number of photons of the radiation and detects the number of photons as the amount of the radiation. The radiation detection device according to any one of claims 1 to 21;
A radiation generating device for irradiating the radiation according to any one of claims 1 to 21;
a collimator having a slit for narrowing an irradiation field of the radiation so that the radiation generated by the radiation generating device is irradiated only to the radiation incident window of the elongated detector;
Collimator moving means for moving the collimator in the inclination direction in synchronization with the movement in the inclination direction of the elongation detector
A radiographic inspection system, characterized in that it is equipped with. 23. The method of claim 22,
A grid arranged on the incident side of the radiation detection device to block or reduce scattered rays of the radiation is provided as a part of the radiation detection device or separately from the radiation detection device. inspection system. 24. The method of claim 22 or 23,
The radiation detection device,
one line segment when one end of the elongate detector before the movement in the first direction is extended along the second direction when the elongate detector moves in the oblique direction with scanning; When the other end of the elongate detector in the first direction is extended in the second direction after the movement has been completed, a two-dimensional region is taken as an edge parallel to each other by the radiation. have as an area,
The slit of the collimator has a spherical shape surrounded by a length of a part of the radiation incident window in the first direction corresponding to the imaging region and a width of the radiation incident window in the second direction. A radiation inspection system, characterized in that formed as a spherical opening formed to narrow the radiation to an area. 25. The method according to any one of claims 22 to 24,
The radiation detection device,
a scanning type radiation detection device configured to move the elongated detector along a horizontal plane or an oblique plane,
A radiological examination system, characterized in that it is incorporated into a radiological diagnosis apparatus diagnosed while a patient is lying in bed, or a non-destructive radiographic examination apparatus in which an object is placed in a horizontal position. 25. The method according to any one of claims 22 to 24,
The radiation detection device,
a scanning type radiation detection device configured to move the elongated detector along a vertical plane,
A radiological examination system, characterized in that it is incorporated into a radiological diagnosis apparatus in which a patient is diagnosed in a standing position, or a non-destructive radiographic examination apparatus in which an object is placed in a vertical position.

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