JP2007278792A - Radiation detection apparatus and radiation detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the apparatus from being made large due to its light source, in a radiation detecting apparatus. <P>SOLUTION: The radiation detecting apparatus comprises: a substrate 2 on which a plurality of pixels each including a transducer element for transducing radiation into an electric signal, are arranged; a light source 7 for irradiating the transducer element with light; and an optical waveguide 6 for propagating the light from the light source 7 to the transducer element. The light source 7 is disposed inside the optical waveguide 6. Shapes of the substrate 2 and the optical waveguide 6 are polygons, and the light source 7 is disposed along at least one side of the polygons. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation detection apparatus and a radiation detection system that detect radiation such as X-rays, α-rays, β-rays, and γ-rays that are applied to medical image diagnostic apparatuses, non-destructive inspection apparatuses, analysis apparatuses, and the like. Particularly, a radiation detection apparatus having a sensor array in which pixels including a conversion element that converts radiation into an electrical signal and a switch element using a non-single crystal semiconductor such as amorphous silicon are two-dimensionally arranged on an insulating substrate. And a radiation detection system.

  Conventionally, direct X-ray imaging of a patient in a hospital has been mainly performed by a so-called film system in which a patient is irradiated with X-rays and the transmitted X-rays are transferred to a photosensitive film via a visible conversion scintillator.

  This film system still has problems in terms of management and operation in the hospital, such as a problem that it takes time from photographing to development, and a need to store and retrieve a large amount of film.

  By the way, there is a method in which a stimulable scintillator is used in place of this film, and an X-ray image of a patient is once stored in the stimulable scintillator and then scanned with a laser beam to read the X-ray image as a digital value.

  If the image is digitized, it can be recorded on various media, so that the image can be easily stored, searched, and transferred, and the efficiency in the management and operation of the hospital is improved.

  Also, obtaining image information as a digital value is expected to improve diagnosis because advanced image processing can be performed at high speed by a computer.

  However, the method using the photostimulable scintillator also takes time from shooting to development, like the film method.

  On the other hand, an X-ray imaging apparatus using a solid-state imaging device such as a CCD or an amorphous silicon semiconductor has been proposed.

  Similar to the film system, this is a system in which an X-ray image of a patient is directly digitized and read by image sensors arranged on a number of two-dimensional arrays via X-rays and a visible conversion scintillator.

  Since a digital image can be obtained almost in real time, there are significant advantages over the film method and the method using a stimulable scintillator.

  In particular, since amorphous silicon can be formed with a large area, an X-ray imaging apparatus using such an image captures a large part such as chest imaging at the same magnification.

  Therefore, the light utilization efficiency is good and a high S / N ratio is expected.

  A large-area X-ray imaging apparatus having a radiation detection element such as amorphous selenium or the like that directly converts X-rays into electric signals without using a visible conversion scintillator has also been proposed.

  In the following, two conventional techniques including a light source for performing an optical reset operation or an optical calibration operation will be described.

  Patent Document 1 shows an example of an X-ray imaging apparatus equipped with an amorphous silicon semiconductor and a visible conversion scintillator.

  FIG. 17 is a cross-sectional view showing an example thereof.

  In FIG. 17, p1, p2, and p3 are photoelectric conversion elements disposed on the surface of the support 40, 1005 is a scintillator that converts X-rays into visible light, and 1006 is a light source disposed on the back surface of each photoelectric conversion element. . Reference numeral 1008 denotes a dichroic layer made of a dielectric film that transmits light of a certain wavelength and reflects light of other wavelengths. Reference numeral 1009 denotes a support 1040 that is not detected by the photoelectric conversion elements p1, p2, and p3. A colored layer that absorbs transmitted light and transmits light from the light source 1006.

  In FIG. 17, a light source 1005 performs an optical reset operation or an optical calibration operation by causing light from the light source 1005 to enter the photoelectric conversion elements p1, p2, and p3. It is arranged for the purpose of improving.

  Next, Patent Document 2 discloses a large-area X-ray imaging apparatus having a radiation detection element such as amorphous selenium that directly converts an X-ray into an electric signal without using a visible conversion scintillator.

  FIG. 18 is a cross-sectional view showing this example.

  In FIG. 18, reference numeral 1015 denotes an X-ray flat panel detector, which includes an X-ray conversion layer 1025, a detection array 1027, and a surface electrode 1031.

  A light source 1017 includes a light guide plate 1041, a light source 1043 disposed outside the light guide plate 1041, a light reflection plate 1045, and a light diffusion plate 1047.

The purpose of arranging the light sources is the same as that of the technique disclosed in Patent Document 1.
Japanese Patent Laid-Open No. 10-206552 JP 2004-33659 A

  By the way, in the technique disclosed in Patent Document 1 among the above conventional techniques, the support 1040, the dielectric film 1008, and the colored layer 1009 are disposed between the light source 1006 and the photoelectric conversion elements p1 to p3, and the thickness thereof is as follows. That space is needed in the direction.

  Further, Patent Document 1 has a description of a light emitting diode (hereinafter referred to as LED) as a light source, and an electric substrate for driving the LED is required because the LEDs are arranged two-dimensionally. .

  In such a configuration, a sufficient space in the thickness direction is required, which not only increases the size of the entire apparatus but also results in a heavy apparatus.

  In particular, in the field of round-trip medical care such as hospital rooms, there is an increasing demand for portability, and there is a drawback that it is not possible to achieve a reduction in size and weight.

  In Patent Document 2, since the light source 1043 of the light source 1017 is arranged outside the light guide plate 1041, the light source 1043 is arranged outside the size of the X-ray flat panel detector. Will grow.

  The demand for a large-area X-ray imaging apparatus can best demonstrate its features in the same-magnification imaging of the chest. The imaging requires a space for placing the chin on the top of the device, and in order to optimally image the chest, esophagus, and pharynx, there is a demand to reduce the distance between the jaw position and the photoelectric conversion element area as much as possible. is there. Therefore, there is a restriction that the light source 1043 of Patent Document 2 cannot be arranged on the upper part.

  When a plurality of light source arrangements are required, the position of the light source is further regulated.

  Even if the light source is placed on the measuring part of the device, the measuring part is located at the part where the patient turns both arms, so in order to keep the balance of the arm turning on both sides, the size of the light source on both sides The device becomes larger by the amount of.

  Furthermore, the portable device has the disadvantage that the size of the light source section is determined by the size and thickness of the light source unit, and it is unavoidable to increase the size accordingly.

  Therefore, an object of the present invention is to avoid an increase in the size of the apparatus due to the light source in the radiation detection apparatus.

  In order to solve the above problems, a substrate on which a plurality of pixels including a conversion element that converts radiation into an electrical signal is arranged, a light source for irradiating light to the conversion element, and the light from the light source being converted A radiation detection apparatus having a light guide plate for propagating to an element, wherein the light source is disposed inside the light guide plate.

  According to the present invention, by arranging the light source inside the light guide plate that propagates and transmits the light, the length, width, and thickness of the radiation detection apparatus can be designed without being influenced by the size of the light source. Is possible.

  Thereby, the limitation of imaging by the protruding portion by the light source is eliminated, and an apparatus that can provide an optimal imaging environment can be achieved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic block diagram of a system using a radiation detection apparatus as an embodiment of the present invention.

  In FIG. 1, 101 is an X-ray generator as a radiation generator, 102 is a subject, 103 is a radiation detector, and 104 is a controller and display.

  First, the subject is positioned in front of the radiation detection apparatus 103 and X-rays are emitted from the X-ray generation apparatus 101. X-rays pass through the body of the subject and enter the radiation detection apparatus 103 with an intensity distribution corresponding to the transmittance.

  In the radiation detection apparatus 103, a scintillator that converts X-rays into light and a two-dimensional photoelectric conversion element array that changes light emitted from the X-rays into electric signals are arranged.

  The photoelectrically converted electrical signal is read out by the controller 104 and displayed as a digital image on the attached display device.

  FIG. 2 is a cross-sectional view of a radiation detection apparatus as one embodiment of the present invention.

  In FIG. 2, 1 is a photoelectric conversion element array, 2 is a support substrate, 3 is a scintillator, 4 is an electromagnetic shield and a light shielding layer, 5 is a light diffusion plate, 6 is a light guide plate, 7 is a light source, 8 is a light reflection layer, 9 Is a light reflection part.

  The X-rays incident on the radiation detection apparatus are transmitted through the electromagnetic shield layer 4 made of a metal sheet such as aluminum and converted into light by the scintillator 3.

  The light is converted into an electrical signal corresponding to the intensity of light by the photoelectric conversion element array 1 arranged two-dimensionally on the support substrate 2 and read out as an image.

  On the other hand, the light diffusing plate 5, the light guide plate 6, the light source 7, the light reflecting layer 8, and the light reflecting portion 9 arranged on the back surface (the surface opposite to the X-ray incident surface) of the support substrate 2 are subjected to optical calibration (or (Also referred to as an optical switch).

  These generate light from a light source before the irradiation with X-rays, and efficiently irradiate the photoelectric conversion element array with the light by the light guide plate 6, the light reflection layer 8, the light reflection portion 9, and the light diffusion plate 5. As a result, the charge transfer efficiency of each photoelectric conversion element is improved.

  Since the present embodiment relates to the structure of the light source and the light guide plate, a detailed description of the optical calibration driving method and control will be omitted.

  FIG. 3 is an enlarged view of a cross-sectional view of the radiation detection apparatus of FIG. 2. Light generated by the light source propagates through the light guide plate 6, and light reflected upward by the light reflecting portion 9 is multidirectional by the light diffusion plate 5. It is the figure which showed a mode that it spread | diffused and is irradiated to a photoelectric conversion element array.

  In FIG. 3, the arrow is the direction of light travel.

  The light reflecting layer 8 reflects the light propagating through the light guide plate 6 and not being reflected by the light reflecting portion 9 but transmitted to the light reflecting layer 8 side again to the light guide plate 6 side, thereby increasing the amount of incident light on the light diffusion plate 5. It is arranged for the purpose.

  The light reflecting portion 9 is a reflection pattern formed by uneven shape or printing attached to the surface of the light guide plate.

  The light diffusion plate 5 is a sheet in which irregular irregularities are formed on the surface of an acrylic or polycarbonate resin.

  Here, the light guide plate 6 is preferably made of a resin material with high light propagation efficiency and high transparency, such as acrylic resin.

  The light source 7 is preferably a high output light source such as an LED, a cold cathode tube, or a semiconductor laser.

  FIG. 4 is a plan view of the radiation detection apparatus of FIG. 2 viewed from the light reflection layer 8 side.

  As is clear from FIGS. 2 and 3, the light source 7 has the same thickness as that of the light guide plate 6 and is disposed in the plane of the light guide plate as is apparent from FIG. 4. That is, the light source 7 is disposed inside the light guide plate 6.

  The arrow indicates the direction when the propagation of light from the light source 7 in the light guide plate 6 is expressed in a plane.

In order to achieve the object, when the thickness of the light guide plate is t1, and the thickness of the light source is t2,
t1 ≧ t2
If so, no problem.

  Needless to say, the size of the light source in the planar direction is within the plane of the light guide plate.

(Embodiment 2)
FIG. 5 is a plan view of the radiation detection apparatus according to the second embodiment of the present invention as viewed from the light reflection layer 8 side.

  The feature of this embodiment is that, compared with the first embodiment, two light sources 7 are arranged in the light guide plate 6 for the purpose of increasing the amount of light and equalizing the distribution of the amount of light applied to the photoelectric conversion elements.

  In FIG. 5, 1 is a photoelectric conversion element array, 6 is a light guide plate, and 7-1 and 7-2 are light sources.

  Although FIG. 5 shows a diagram in which the light sources 7-1 and 7-2 are arranged on two adjacent sides, they may be arranged on two opposite sides (not shown).

(Embodiment 3)
FIG. 6 is a plan view of the radiation detection apparatus according to the third embodiment of the present invention as viewed from the light reflection layer 8 side.

  In the present embodiment, similarly to the second embodiment, a light source 7 is arranged in the vicinity of each side in the light guide plate 6 for the purpose of further increasing the amount of light and making the distribution of the amount of light irradiated to the photoelectric conversion element uniform. A total of four light sources are arranged.

  In FIG. 6, 1 is a photoelectric conversion element array, 6 is a light guide plate, and 7-1 and 7-2 to 4 are light sources.

  In this case, not only the amount of light is improved, but also the light propagates from the periphery of the light guide plate 6 toward the center, so that the distribution of the amount of light applied to the photoelectric conversion element array has a uniform distribution concentrically with respect to the center. It is done.

(Embodiment 4)
FIG. 7 is a plan view of the radiation detection apparatus according to the fourth embodiment of the present invention viewed from the light reflection layer 8 side.

  For example, when the light source 7 is a cold cathode tube, the cold cathode tube emits light in the direction of 360 degrees about the axis of the tube.

  Further, the LED or the semiconductor laser can emit light in two directions.

  An embodiment that considers these characteristics is this embodiment.

  As can be seen from FIG. 7, the light source 12 is arranged on a straight line in the center parallel to the side of the light guide plate, so that one light source can emit light in two arrow directions in the figure. Further, light propagation is possible in a half region of the light guide plate 6 as compared with the first embodiment, and the amount of light applied to the photoelectric conversion element array can be improved. The light from the light source can be used efficiently.

(Embodiment 5)
FIG. 8 is a plan view of the radiation detection apparatus according to the fifth embodiment of the present invention viewed from the light reflection layer 8 side.

  The present embodiment is a modification of the fourth embodiment, and the light source 13 is arranged obliquely with respect to the two opposite sides of the light guide plate 6.

  At that time, the amount of light applied to the photoelectric conversion element array from the light source 13 is guided so that the right and left of the light guide plate are equal to the light source 13 or so that the areas of the left and right light guide plates are equal to the light source 13. A light source 13 is disposed in the light plate 6.

(Embodiment 6)
FIG. 9 is a plan view of the radiation detection apparatus according to the sixth embodiment of the present invention viewed from the light reflection layer 8 side.

  In FIG. 9, the light source 14 is arranged on a line connecting a pair of diagonals of the light guide plate 6. The difference between the present embodiment and the fifth embodiment is that the light source 14 is arranged in the light guide plate under the longest condition. It is to have done.

  Thereby, the amount of light irradiated to the photoelectric conversion element array can be maximized with one light source.

(Embodiment 7)
FIG. 10 is a plan view of the radiation detection apparatus according to the seventh embodiment of the present invention viewed from the light reflection layer 8 side.

  As is apparent from FIG. 10, the present embodiment is that the light sources 14-1, 14-2, and 14-3 are arranged on two pairs of diagonal lines connecting the respective diagonals.

  As a result, the amount of light applied to the photoelectric conversion array can be further improved and the distribution of the light applied to the photoelectric conversion element array can be made more uniform than in the sixth embodiment.

(Embodiment 8)
FIG. 11 is a plan view of the radiation detection apparatus according to the eighth embodiment of the present invention viewed from the light reflection layer 8 side.

  The feature of this embodiment is that an annular light source 15 having the center of the light guide plate 6 as the center is disposed, as is apparent from FIG.

  The difference from the above embodiment is that an annular light source 15 is arranged, so that the distribution of the irradiation light to the photoelectric conversion element array is irradiated with light having the same distribution concentrically with respect to the center of the photoelectric conversion element array. It becomes possible to do. Further, by optimizing the distance between the center of the light guide plate 6 and the light source 15, it is possible to make the irradiation light distribution to the photoelectric conversion element array substantially uniform.

(Embodiment 9)
FIG. 12 is a plan view of the radiation detection apparatus according to the ninth embodiment of the present invention viewed from the light reflection layer 8 side.

  In the present embodiment, the reflective layer 20 is disposed on the side surface around the light guide plate 6.

  As a result, the light generated by the light source and propagated through the light guide plate 6 is reflected by the reflective layer 20 and further propagates in a different direction of propagation, thereby enabling further effective use and uniformization of the light.

  FIG. 12 shows an example in which the reflective layer 20 is arranged in the case of the sixth embodiment, but it goes without saying that the same effect can be obtained even when applied to the first to fifth and seventh to ninth embodiments.

(Embodiment 10)
FIG. 13 is an enlarged cross-sectional view of a tenth embodiment of the present invention.

  Up to now, the relationship between the light guide plate and the light source indicates that the light source is disposed in the groove or gap in the plane of the light guide plate and the thickness of the light source is equal to or less than the thickness of the light guide plate, as shown in FIG. I came.

  In contrast, the present embodiment is an example in which the method of arranging the light source with respect to the light guide plate is changed. The same applies to the following embodiments 11 and 12.

  In FIG. 13, the light source 11 is disposed on the light diffusion plate 5 side inside the light guide plate 6.

  As a result, the light source is isolated from the external atmosphere, and thus is less susceptible to external humidity and the like.

(Embodiment 11)
FIG. 14 is an enlarged cross-sectional view of an eleventh embodiment of the present invention.

  In FIG. 14, the light source is disposed in the groove disposed on the side surface of the light guide plate 6.

  Compared to FIG. 13, the structure is more susceptible to external influences, but on the other hand, the light source can be arranged from the measuring portion of the light guide plate after the light guide plate is arranged, and assembly and manufacture are facilitated.

Embodiment 12
FIG. 15 is an enlarged cross-sectional view of a twelfth embodiment of the present invention.

  FIG. 15 is a diagram showing a product manufactured by arranging a light source inside the light guide plate when the light guide plate is manufactured. Manufacture can be performed by casting.

  Further, the light sources can be arranged in the arrangement forms of all the above embodiments.

  Thereby, the influence from the outside can be prevented, and since it is fixed in the light guide plate, the positional deviation of the light source due to vibration is eliminated.

  As mentioned above, although the light source was described only in the case of the first embodiment, it is possible in the case of other embodiments. As in the first embodiment, there is no problem even if the light source is a cold cathode tube, LED, or semiconductor.

(Embodiment 13)
FIG. 16 is an enlarged cross-sectional view of a thirteenth embodiment of the present invention.

  The present embodiment is an example in which an EL (electro-luminescence) 16 is mounted on a light source.

  Since EL can obtain a uniform light emission distribution in a plane, it can be provided as a more advantageous light source.

  The EL 16 can also be arranged with a groove in the light guide plate 6, but the one formed integrally with the light guide plate 6 has less light loss due to the air layer and less influence from the outside. The above handling is also advantageous.

  In this specification, an example is shown in which X-rays are used as radiation. However, radiation includes α-rays, β-rays, γ-rays, and the like, which are beams formed by particles (including photons) emitted by radiation decay. . In addition, a beam having the same or higher energy, such as a particle beam or a cosmic ray, is included in the radiation.

  The present invention is used for a radiation detection apparatus used in the fields of medical diagnostic equipment, non-destructive testing equipment, and the like.

1 is a schematic block diagram of a system using a radiation detection apparatus as one embodiment of the present invention. It is sectional drawing of the radiation detection apparatus as one Embodiment of this invention. It is an enlarged view of sectional drawing of the radiation detection apparatus of FIG. It is the top view which looked at the radiation detection apparatus of FIG. 2 from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 2nd Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 3rd Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 4th Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 5th Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 6th Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 7th Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 8th Embodiment of this invention from the light reflection layer 8 side. It is the top view which looked at the radiation detection apparatus of the 9th Embodiment of this invention from the light reflection layer 8 side. It is an expanded sectional view of the 10th embodiment of the present invention. It is an expanded sectional view of the 11th Embodiment of this invention. It is an expanded sectional view of the 12th Embodiment of this invention. It is an expanded sectional view of the 13th Embodiment of this invention. It is sectional drawing which shows an example of a prior art. It is sectional drawing which shows an example of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoelectric conversion element array 2 Support substrate 3 Scintillator 4 Electromagnetic shield and light shielding layer 5 Light diffusing plate 6 Light guide plate 7 Light source 8 Light reflection layer 9 Light reflection part 16 EL

Claims (15)

A substrate on which a plurality of pixels including a conversion element that converts radiation into an electrical signal are arranged, a light source for irradiating light to the conversion element, and a light guide plate for propagating the light from the light source to the conversion element In a radiation detection apparatus comprising:
The radiation detection apparatus according to claim 1, wherein the light source is disposed inside the light guide plate. The radiation detection apparatus according to claim 1, wherein the substrate and the light guide plate are polygonal, and the light source is provided along at least one side of the polygon. The radiation detection apparatus according to claim 2, wherein the light source is provided along a plurality of sides of the polygon. The radiation detection apparatus according to claim 3, wherein the polygon is a rectangle. The radiation detection apparatus according to claim 4, wherein the light source is provided along four sides. The radiation detection apparatus according to claim 1, wherein the substrate and the light guide plate are rectangular, and the light source is disposed in parallel to a side of the light guide plate and at substantially the center of the rectangle. The radiation detection apparatus according to claim 1, wherein the substrate and the light guide plate are rectangular, and the light source is arranged to be symmetric with respect to a center line of the light guide plate. The radiation detection apparatus according to claim 1, wherein the substrate and the light guide plate are rectangular, and the light source is disposed on a diagonal line of the light guide plate. The radiation detection apparatus according to claim 1, wherein the substrate and the light guide plate are square, the light source is annular, and the center of the annular light source is at the same position as the center of the square. . The radiation detection apparatus according to claim 1, wherein a reflective layer is provided on a side surface around the light guide plate. The radiation detection apparatus according to claim 1, wherein the light source is disposed on the substrate side. The radiation detection apparatus according to claim 1, wherein a groove is provided at an end of the light guide plate, and the light source is provided in the groove. The radiation detection apparatus according to claim 1, wherein the light guide plate and the light source are integrally manufactured. The radiation detection apparatus according to claim 1, wherein the light source is formed in the same shape as the light guide plate. A radiation generator;
The radiation detection apparatus according to any one of claims 1 to 14,
And a controller for reading out an electrical signal converted by the conversion element.