JP2010233880A - Imaging instrument, imaging method, imaging apparatus, and method for determining subject image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire whether a picked-up image is irradiated with radiation from an appropriate direction. <P>SOLUTION: This imaging instrument 30 for use in imaging a subject using radiation is formed with a regulating frame 44 on a base 42, and is formed with a reference part 46 and an instrument storage part 48 within a region surrounded in T-shape by the regulating frame. A slope 40 and a determining instrument 32 are arranged in the instrument storage part. The determining instrument 32 is formed in block shape using a radiation non-transmitting member and is formed with a plurality of cavity parts 34. Each cavity part is formed to extend from one end face to the other end face with a constant cross section. Consequently, when the base arranged in parallel with a storage phosphor sheet is vertically irradiated with radiation, an image corresponding to the open cross section of the cavity parts can be acquired, but when the base is obliquely irradiated with radiation, an image narrower than the open cross section is acquired. Whether radiation is irradiated in an appropriate direction can thereby be determined. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging instrument, an imaging method, an imaging apparatus, and a subject image determination method used for forming a subject image by radiation transmitted through the subject.

  In the medical field, a diagnostic image formed based on an image obtained by receiving radiation transmitted through a subject with a radiation receiving medium and using a person or the like as an examination target (subject) is often used. That is, in a living body, the absorption of radiation differs depending on the tissue, so that a diagnostic image corresponding to the tissue part distribution of the living body can be obtained from the energy distribution of the radiation that has passed through the living body.

  For the generation of such a diagnostic image using radiation, for example, a layer made of a stimulable phosphor that absorbs radiation energy when irradiated with radiation and generates stimulated emission when irradiated with excitation light is used. Using the provided stimulable phosphor sheet as a radiation receiving medium, the stimulable phosphor sheet is irradiated with radiation that has passed through the site to be inspected, and radiation image information is recorded. By irradiating this stimulable phosphor sheet while scanning with excitation light, and reading the emitted light in time series, an image corresponding to the examination site is obtained. Such radiographic images are frequently used for bone mineral quantitative examinations and the like.

  On the other hand, density unevenness may occur in a radiographic image, and proper image diagnosis becomes difficult due to this density unevenness. From here, the shading correction is performed on the image data of the radiographic image. At this time, a so-called solid area is provided where radiation that does not pass through the subject is irradiated as it is, and the image density of this solid area is used.

  Moreover, in a radiographic image, even if the same site | part is imaged, a density difference may arise. From this, there is a proposal that uses a wedge whose density changes step by step when it is imaged, images the wedge together with the subject, and corrects the gradation of the captured image using the density change of the pixel value formed by this wedge. (For example, refer to Patent Document 1).

  By the way, when performing bone mineral quantification etc. using a radiographic image, a proper diagnostic image may not be obtained unless radiation is irradiated perpendicularly to an imaging medium such as a stimulable phosphor sheet. That is, if radiation is irradiated obliquely to the imaging region, the shadow of the imaging region changes, for example, when the skeleton is imaged, the thickness of the skeleton changes.

JP 2002-119499 A

  The present invention has been made in view of the above-described facts, and an object thereof is to provide an imaging instrument, an imaging method, an imaging apparatus, and a method for determining a captured subject image that can obtain an appropriate radiation transmission image. .

  In order to achieve the above object, the present invention of claim 1 is directed to irradiating the subject from the radiation irradiated to the radiation irradiation surface by irradiating the radiation irradiation surface of the radiation receiving medium with radiation including radiation transmitted through the subject. An imaging instrument used for imaging a subject image for acquiring an image, the determination instrument body formed by a non-radiation transmitting member and disposed together with the subject and facing the radiation irradiation surface, and the determination instrument body In the state facing the radiation irradiation surface, the determination instrument body is formed so as to reach the other end side from one end side along the contact and separation direction with the radiation irradiation surface, and the cross section in the direction along the radiation irradiation surface is constant. And a determination instrument having a radiation transmitting portion surrounded by the non-radiation transmitting member.

  According to the present invention of claim 2, the radiation transmitted through the placement surface on which the subject is placed is irradiated onto the radiation irradiation surface of the radiation receiving medium, so that the subject from the radiation irradiated on the radiation irradiation surface. An imaging instrument used for imaging a subject image for acquiring an image, the determination instrument body formed by a non-radiation transmitting member and disposed on the placement surface, and the determination instrument body on the placement surface Is formed in the determination instrument main body so as to reach the other end side from one end side along the contact and separation direction with the mounting surface, the cross section in the direction along the mounting surface is constant, A determination instrument having a radiation transmitting portion surrounded by the non-radiation transmitting member.

  According to the present invention, the radiation applied to the subject and the determination instrument is applied to the radiation irradiation surface of the radiation receiving medium, and an image transmitted through the radiation transmitting portion of the determination instrument together with the subject image is obtained.

  At this time, the image of the determination instrument according to the cross-sectional load of the radiation transmitting part formed in the determination instrument is obtained by irradiating the radiation substantially perpendicular to the radiation irradiation surface. On the other hand, when the radiation is irradiated obliquely with respect to the radiation receiving surface, the radiation is blocked or absorbed by the peripheral portion of the radiation transmitting portion, so the image of the determination instrument is more than the cross section of the radiation transmitting portion. Narrow.

  Thereby, it can be determined from the image according to the ray transmission part currently formed in the determination instrument whether the radiation was radiated | emitted from the appropriate direction with respect to the radiation light-receiving surface.

  According to a third aspect of the present invention, there is provided an imaging instrument including a regulation instrument that is framed in a long rectangular shape by a regulation frame made of a radiation transmitting member and is arranged so as to protrude from the placement surface.

  According to the present invention, the radiation receiving medium can be formed with a region irradiated with radiation that does not pass through the subject by the regulating device. Thereby, it is possible to perform appropriate image processing on the captured image based on the image density obtained from this region.

  The imaging device according to claim 4 is formed such that a transmission amount of the radiation is gradually changed from one end side to the other end side in the longitudinal direction, and is accommodated in the regulation frame of the regulation device. And a slope member disposed on the mounting surface.

  According to the present invention, it is possible to include an image in which the density is changed stepwise on the captured image obtained by the radiation irradiated to the radiation receiving medium. Bone mineral density can be obtained.

  According to a fifth aspect of the present invention, there is provided a method for capturing a subject image, wherein the subject image is picked up by a non-radiation transmitting member on a placement surface disposed opposite to a radiation irradiation surface of a radiation receiving medium. The determination instrument main body and the determination instrument main body are formed on the determination instrument main body so as to reach from the one end side along the contact / separation direction to the other end side with the determination instrument main body disposed on the placement surface. An imaging device including a determination device having a cross section in a direction along the mounting surface constant and a radiation transmitting portion surrounded by the non-radiation transmitting member; and A subject may be placed on the surface and irradiated with radiation so that the radiation transmitted through the subject and the imaging device is irradiated onto the radiation irradiation surface of the radiation receiving medium.

  Further, in the subject image capturing method of the present invention, the imaging instrument includes a regulation instrument framed in a long rectangular shape by a regulation frame made of a radiation transmitting member, and the regulation frame protrudes from the mounting surface. The control device may be arranged so as to capture the subject image, and the imaging device has a stepwise transmission of the radiation from one end side to the other end side in the longitudinal direction. A slope member formed to be changed may be included, and the subject may be imaged by accommodating the slope member in the restriction frame of the restriction device.

  In such an imaging apparatus to which the present invention is applied, the radiation including the radiation that has passed through the subject is irradiated onto the radiation irradiation surface of the radiation receiving medium, so that the subject image is extracted from the radiation irradiated on the radiation irradiation surface. An imaging device to be acquired, comprising: a determination instrument body formed by a non-radiation transmitting member and disposed on the placement surface; and the determination instrument body is disposed on the placement surface and placed on the placement surface. The cross section in the direction along the direction is constant, and the periphery is surrounded by the non-radiation transmitting member so as to reach the other end side from the one end side along the contact / separation direction with the placement surface. It is only necessary to include a determination instrument having a radiation transmitting portion.

  In addition, the imaging apparatus of the present invention includes a restriction instrument that is formed by being framed in a long rectangular shape by a restriction frame made of a radiation transmitting member, and arranged so that the restriction frame protrudes from the placement surface. Further, the mounting surface is formed so that the amount of transmission of the radiation is gradually changed from one end side to the other end side in the longitudinal direction, and is accommodated in the restriction frame of the restriction instrument. A slope member disposed above may be included.

  On the other hand, the subject image determination method of the present invention is a subject image determination method for determining the suitability of the subject image captured by the subject image capturing method according to claim 5, wherein the subject image is determined along the mounting surface. The cross-sectional area of the radiation transmitting member of the determination instrument is compared with the projected area of the radiation transmitting member of the determination instrument formed on the radiation receiving medium, and the subject image formed on the radiation receiving medium Judge the suitability of the.

  When the radiation irradiation surface and the mounting surface of the radiation receiving medium are arranged so as to be substantially parallel, the radiation receiving surface is formed on the radiation irradiation surface according to the radiation irradiation direction (angle) with respect to the radiation irradiation surface (mounting surface). The projected area of the radiation transmitting member changes.

  From here, it can be determined whether or not the subject image is formed by irradiating radiation from a desired direction from the cross-sectional area of the radiation transmitting member and the projected area of the radiation transmitting member on the radiation receiving medium. .

  In the subject image determination method of the present invention, when the ratio of the transparent area to the cross-sectional area of the radiation transmitting member is within a preset range, it is determined that the subject image is appropriate. good.

  For example, when performing bone mineral quantification, it is preferable that the radiation is irradiated substantially perpendicularly to the radiation irradiation surface of the radiation receiving medium. In this case, the projected area of the radiation transmitting member is equal to the cross-sectional area of the radiation transmitting member. The projection area of the radiation transmitting member becomes narrower as the angle substantially coincides and the angle of the radiation irradiation surface with respect to the vertical direction increases.

  From this, it can be determined that the subject image is appropriate when the ratio of the transparent area to the cross-sectional area of the radiation transmitting member is within a preset range.

  As described above, according to the present invention, it is possible to accurately determine whether or not the radiation is irradiated in an appropriate direction from the image of the radiation transmitting portion formed on the determination instrument. It has the effect that the used highly accurate image diagnosis becomes possible.

  Further, in the present invention, a region irradiated with radiation that does not transmit through the subject can be formed on the radiation irradiation surface by the restriction frame, so that accurate shading correction can be performed from the image of this region.

  Furthermore, in this invention, since the image of the radiation which permeate | transmitted the slope member is contained, appropriate gradation correction | amendment and bone mineral quantity determination are attained from this image.

  In the present invention, since it is determined from the projection image of the radiation transmitting member formed on the radiation receiving medium whether or not the radiation is irradiated from an appropriate direction, an appropriate bone mineral amount is determined from the subject image using the radiation. It can be carried out.

It is a schematic perspective view of the imaging tool applied to this Embodiment. It is the schematic which shows an example of an imaging system. (A) is a schematic perspective view which shows an example of the determination instrument applied to this Embodiment, (B) is the schematic which shows irradiation of the radiation to a determination instrument, (C) is obtained by irradiating a radiation. It is the schematic which shows an example of the determination image. It is a schematic perspective view which shows an example of the imaging using the imaging tool. It is the schematic which shows an example of the captured image obtained by imaging. (A)-(D) are schematic which shows the other example of the determination instrument. (A) is the schematic which shows the other example of a determination instrument, (B) And (C) is the schematic which shows the determination image obtained from the determination instrument of (A). It is the schematic which shows the determination instrument which formed the character. It is the schematic which shows an example of the imaging instrument using the determination instrument of FIG. It is the schematic which shows an example of the captured image obtained using the imaging tool of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of the imaging system 10 according to the present embodiment. The imaging system 10 includes a support column 12, and this support column 12 is erected from a base 12A. In addition, the imaging table 14 is attached to the support column 12 so as to be movable up and down by a lifting mechanism (not shown), and a light source hood 16 is provided above the imaging table 14 (above the paper surface in FIG. 2).

  In the imaging system 10, an imaging region of a person (subject 26) who is a subject is opposed to the imaging table 14. In the imaging system 10, a radiation light source 18 is provided in the light source hood 16, and radiation is emitted from the radiation light source 18 onto the imaging table 14.

  In the following description, the surface of the imaging table 14 on which the imaging part is placed is directed upward and the radiation light source 18 is opposed to the surface. However, the imaging system to which the present invention is applied is described below. However, the imaging table to which the imaging part is opposed may be directed in an arbitrary direction such as a horizontal direction. At this time, the radiation light source moves so as to face the surface of the imaging table. Any configuration can be used.

  A radiation receiving medium is provided in the imaging table 14, and the radiation that has passed through the imaging part of the subject 26 placed on the imaging table 14 is irradiated onto the radiation receiving medium. As this radiation receiving medium, any configuration can be applied as long as it can form an image (captured image) corresponding to the distribution (for example, energy distribution) of the radiation transmitted through the imaging region.

  Here, as shown in FIG. 4, in the present embodiment, a stimulable phosphor sheet 20 having a layer made of a stimulable phosphor is used as an example of a radiation receiving medium. The stimulable phosphor absorbs this radiation energy when irradiated with radiation, and generates and absorbs stimulated light when irradiated with excitation light such as laser light while absorbing the radiation energy. It emits fluorescence according to the radiation energy.

  In the present embodiment, the stimulable phosphor sheet 20 provided with the layer made of the stimulable phosphor is accommodated in the cassette 22. The cassette 22 includes a casing 24 having a rectangular thin box shape and a light shielding property but capable of transmitting radiation, and the stimulable phosphor sheet 20 is accommodated in the casing 24. At this time, the stimulable phosphor sheet 20 is accommodated so that the surface thereof is along the surface of the housing 24.

  As shown in FIG. 2, in the imaging system 10, the cassette 22 is loaded on the imaging table 14. In the imaging system 10, the stimulable phosphor sheet 20 in the cassette 22 loaded on the imaging table 14 is irradiated with radiation. At this time, the imaging part of the subject 26 is placed on the imaging table 14, so that radiation image information by radiation that has passed through the imaging part is recorded on the stimulable phosphor sheet 20.

  Thereafter, the cassette 22 is loaded into, for example, an image information reading / reproducing apparatus. In the image information reading / reproducing apparatus, the stimulable phosphor sheet 20 is irradiated with scanning excitation light, and the fluorescence emitted from the stimulable phosphor sheet is read in time series so that the captured image corresponding to the radiographic image information can be read. Image data is obtained.

  Thereby, the radiation image information recorded on the stimulable phosphor sheet 20 can be visualized. An image obtained from such irradiation line image information is a monochromatic image, and is expressed by a gradation (density) corresponding to radiation energy.

  Here, for example, the bone mineral content of the skeleton can be determined by including a human skeleton in the imaging region. When performing this bone mineral quantification, tone correction and shading correction are performed. That is, the image data obtained from the radiographic image information can be subjected to predetermined image processing such as image processing such as shading correction and gradation correction, whereby bone mineral content can be quantified by, for example, the MD method.

  By the way, in the imaging system 10 applied to this Embodiment, when radiographic image information is recorded on the stimulable phosphor sheet 20, a predetermined imaging instrument is used. FIG. 1 shows an imaging tool 30 as an example.

  In the following description, the hand 28 of the subject 26 is applied as a structure to be imaged, and in this embodiment, radiation image information for obtaining a skeleton image of the hand 28 on the stimulable phosphor sheet 20 is used. Is recorded (imaged). In addition, by fixing the imaging device 30 to the imaging table 14 in advance, the imaging device 30 can be applied to imaging an arbitrary part with the imaging table 14 facing in an arbitrary direction.

  Further, in the present embodiment, a description will be given on the assumption that the hand 28 as an imaging region is placed on the surface of the casing 24 of the cassette 22 loaded on the imaging table 14. Further, in the following, when viewing the imaging table 14 or the cassette 22 loaded on the imaging table 14 from the subject 26, the right side in the left-right direction is indicated by the arrow R, the left side is indicated by the arrow L, and the back side is indicated by the arrow B. It shows with.

  The imaging tool 30 includes a determination tool 32. As shown in FIG. 3A, the determination instrument 32 uses a radiation absorbing member such as aluminum or a radiation shielding member (radiation non-transparent member), and has an outer shape of a rectangular block shape. The determination instrument 32 is formed with a plurality of cavities 34 as radiation transmitting portions.

  Each of the hollow portions 34 has a rectangular cross-sectional opening, and the determination instrument 32 is hollowed in a columnar shape from one end surface 32A to the other end surface 32B between the end surfaces 32A facing each other. ing. That is, in the determination instrument 32, the penetration direction of the cavity 34 is a direction orthogonal to the end face 32A.

  As a result, as shown in FIG. 3B, in the determination instrument 32, when radiation is irradiated substantially perpendicular to the end face 32A (indicated by a two-dot chain line in FIG. 3B), the cavity portion 34 is obtained. The radiation irradiated on the determination instrument 32 passes through the determination instrument 32, and the radiation irradiated around the cavity 34 is blocked by the determination instrument 32.

  Further, in the determination instrument 32, when radiation is irradiated in a state inclined with respect to the end surface 32A (for example, a state inclined at an angle α with respect to the vertical line of the end surface 32A, a solid line in FIG. 3B). As shown, radiation is blocked at the periphery of the cavity 34, and even a portion of the radiation irradiated into the cavity 34 is blocked by the determination instrument 32.

  Thereby, as shown in FIG. 3C, when the end face 32 </ b> A of the determination instrument 32 is arranged along the surface of the stimulable phosphor sheet 20, the determination instrument 32 is obtained from the radiation irradiated. In the image (projected image by radiation, hereinafter referred to as determination image 36), the area of the high density portion 38 by the radiation transmitted through the cavity 34 is narrow. In addition, in FIG. 3, the irradiation direction of a radiation is shown by the arrow.

  The area of the high-concentration portion 38 is determined by the radiation irradiation angle α and the height H of the determination tool, and varies depending on the radiation irradiation angle α, and is an angle (substantially vertical) that is considered to be perpendicular or perpendicular to the end face 32A. If present, the area of the high-concentration portion 38 is the largest (indicated by a two-dot chain line in FIG. 3C), and becomes narrower when the inclination of radiation increases and the irradiation angle α increases, and the irradiation angle α exceeds a predetermined angle. Then, the high density portion 38 does not appear.

  Therefore, by using the determination tool 32, it is possible to determine whether or not the radiation irradiation angle α is appropriate based on the determination image 36 obtained from the radiation applied to the determination tool 32. That is, it can be determined from the determination image 36 whether or not the irradiation angle α is within a preset range.

  On the other hand, as shown in FIGS. 1 and 4, the imaging tool 30 includes a slope 40. The slope 40 is formed in a band plate shape using a material whose amount of radiation absorption (transmission) varies depending on its thickness, such as aluminum. Moreover, the thickness of the slope 40 is gradually changed from one end side in the longitudinal direction toward the other end side. That is, the cross section along the longitudinal direction of the sleep 40 has a substantially triangular shape, one end side in the longitudinal direction is thin so as to transmit radiation, and the other end side is thick so as to block radiation.

  As a result, the density of the image (hereinafter referred to as phantom image) obtained from the radiation image information transmitted through the slope 40 changes smoothly from one end side to the other end side in the longitudinal direction.

  Further, the imaging device 30 includes a rectangular flat base 42, and a restriction frame 44 is formed on the base 42. The restriction frame 44 is formed to stand up to a predetermined height (for example, about 5 mm to 10 mm) from the surface of the base 42 so as to provide a substantially T-shaped space on the base 42.

  Thereby, on the base 42, the longitudinal direction extends from the reference portion 46 along one side of the base 44 and the intermediate portion of the reference portion 46 in the longitudinal direction in a direction intersecting the longitudinal direction of the reference portion 46. An instrument housing portion 48 is formed.

  Here, the instrument accommodating part 48 becomes a magnitude | size which can accommodate the above-mentioned determination instrument 32 and the slope 40 along with a longitudinal direction. Further, the base 42 is divided into a region 50L and a region 50R by the instrument housing portion 48.

  In the imaging device 30, the base 42 and the regulation frame 44 are formed of a radiation transmitting member such as resin. Further, as shown in FIG. 4, the size of the base 42 is a size corresponding to the size of the stimulable phosphor sheet 20 (for example, the size of the recording area of the radiation image information). The imaging tool 30 is used by being placed on the imaging table 14 or the casing 24 of the cassette 22 loaded on the imaging table 14. At this time, in the imaging instrument 30, the determination instrument 32 and the slope 40 are accommodated in the instrument accommodating portion 48, and the end face 32 </ b> A of the determination instrument 32 is stored in the cassette 22. Arranged along the surface.

  In the imaging system 10, for example, when imaging the hand of the subject 26, the imaging instrument 30 is used. Here, imaging using the imaging tool 30 and diagnostic images obtained thereby will be described.

  When imaging the hand 28 of the subject 26 using the imaging instrument 30, as shown in FIG. 4, the imaging instrument 30 is placed on the cassette 22 (the surface on the radiation light source 18 side) loaded on the imaging stage 14. Is placed.

  In this state, the subject 26 places the hand 28 on the base 42 of the imaging instrument 30. At this time, since the instrument housing portion 48 is formed at an intermediate portion of the base 42 in the left-right direction (left-right direction as viewed from the subject 26), the left hand 28L is placed on the region 50L of the base 42 and the right hand 28R. Is placed in the region 50R of the base 42.

  Here, since the restriction frame 44 is formed on the base 42 of the imaging tool 30 so as to partition the regions 50L and 50R, the subject 26 accurately positions the left hand 28L and the right hand 28R. Can be judged. In addition, since the restriction frame 44 is formed, it is possible to reliably prevent a part of the hand 28 of the subject 26 from entering the reference unit 46 and the instrument housing unit 48.

  That is, by using the imaging tool 30, the imaging part (in this case, the hand 28) of the subject 26 can be arranged at an appropriate position on the stimulable phosphor sheet 20.

  In the imaging system 10, when the imaging part is placed on the imaging table 14 in this way, radiation is emitted from the radiation light source 18 and imaging is performed to record radiation image information on the stimulable phosphor sheet 20 in the cassette 22. .

  When imaging is performed, the cassette 22 is removed from the imaging table 14 and loaded into the image information reading / reproducing apparatus. Thereby, the captured image according to the radiation image information of the stimulable phosphor sheet 20 is obtained. FIG. 5 shows a captured image 52 as an example at this time. In this captured image 52, an image 56L of the left hand 28L is formed in a region 54L corresponding to the region 50L of the imaging tool 30, and an image 56R of the right hand 28R is formed in a region 54R corresponding to the region 50R.

  The reference unit 46 of the imaging instrument 30 is irradiated with radiation as it is. Thereby, on the captured image 52, the area corresponding to the reference unit 46 is the solid area 58 having the highest density.

  Further, on the captured image 52, a region between the region 54 </ b> L and the region 54 </ b> R corresponds to the instrument storage unit 48 of the imaging instrument 30, and determination that the region is stored in the instrument storage unit 48. A determination image 36 of the instrument 32 and an image of the slope 40 (slope image 60) are formed.

  In the captured image 52 formed in this way, appropriate shading correction for density unevenness can be performed by using the image density of the solid area 58.

  The slope image 60 formed in the captured image 52 is formed so as to change stepwise (smoothly) as the density is set in advance. By using this slope image 60, the captured image is displayed. The gradation correction for 52 can be performed, and the bone mineral quantitative determination can be performed by the slope image 60.

  A known technique can be applied to shading correction, gradation correction, and bone mineral quantification using the captured image 52 for the captured image 52.

  On the other hand, the imaging instrument 30 is provided with a determination instrument 32, and the captured image 52 includes a determination image 36 of the determination instrument 32. The determination instrument 32 is provided with a cavity 34 through which radiation passes. As a result, a high density portion 38 appears in the determination image 36.

  Here, the high-density portion 38 of the determination image 36 is obtained when the radiation is emitted substantially perpendicularly to the end face 32A of the determination instrument 32, that is, the stimulable phosphor sheet 20, the cavity 34 of the determination instrument 32. It has a shape corresponding to the opening cross section and a maximum shape (maximum area).

  On the other hand, when the radiation is irradiated obliquely onto the end face 32A of the determination instrument 32, that is, when the stimulable phosphor sheet 20 is irradiated obliquely, the high density portion 38 in the determination image 36 is small. When the area becomes narrower and the inclination of radiation increases, the high density portion 38 disappears.

  Therefore, in the captured image 52 captured using the imaging instrument 30 including the determination instrument 32, it is determined whether or not the radiation has been applied to the stimulable phosphor sheet 20 at an appropriate angle (here, substantially vertical). Can be determined.

  Thereby, when it determines with the radiation having been irradiated from the appropriate direction, exact bone mineral_quantity | quantitative_assay is obtained. That is, when the stimulable phosphor sheet 20 is irradiated with radiation obliquely, the thickness of the skeleton projection image on the stimulable phosphor sheet 20 changes. For this reason, even if bone mineral content is determined based on the width and concentration of the skeleton on the captured image 52, an accurate bone mineral content quantitative test cannot be performed.

  At this time, by using the determination image 36 obtained by the determination instrument 32, it is possible to obtain an accurate bone mineral quantification from the captured image 52 by confirming whether or not the radiation is emitted from an appropriate direction. It is possible to reliably determine whether or not an erroneous determination of bone mineral content has occurred.

  Whether or not appropriate bone mineral content can be determined is determined by measuring the area of the projection image (projection area) of the cavity 34 in the determination image 36 and the ratio of the projection area to the opening area of the cavity 34 of the determination instrument 32. May be determined based on whether or not is within a preset allowable range.

  At this time, if it is determined that the radiation irradiation angle α is large and out of the allowable range, bone mineral quantification may be stopped using the captured image 52. Further, the images 56L and 56R that are subject images may be corrected using the ratio of the projected area to the aperture area.

  When such a determination is made, the radiation image information recorded on the stimulable phosphor sheet 20 is read and read by a reading device, for example, an extraction unit that extracts a projection image in the determination image 36 from the captured image 52, an extraction unit Calculating means for calculating the area of the projection image extracted by the calculation means, comparing means for comparing the area calculated by the calculating means with the opening area of the cavity 34 set in advance, and determining means for determining suitability from the comparison result of the comparing means As long as it contains

  On the other hand, in the present embodiment, the imaging instrument 30 and the determination instrument 32 are used. However, the imaging instrument only needs to include at least the determination instrument, and thereby, the storage fluorescence that is a radiation receiving medium. It is possible to accurately determine whether the body sheet 20 is irradiated with radiation at an appropriate angle.

  In addition, the imaging instrument and the determination instrument are not limited to the imaging instrument 30 and the determination instrument 32, and any configuration can be applied.

  For example, in the determination instrument 32, the cavity portions 34 having a rectangular cross-sectional opening are provided at four locations, but the determination instrument is not limited to this, and may be a determination instrument in which one cavity portion 34 is formed. In addition, as shown in FIGS. 6A and 6B, the cross-sectional opening may have a shape other than a rectangle. The determination instrument 70 shown in FIG. 6A is formed in a rectangular block shape, and a cavity 72 having a circular cross-sectional opening is formed. Moreover, the determination instrument 74 shown in FIG. 6B is formed in a rectangular block shape, and a cavity 76 having a cross-sectional (+: plus) cross-sectional opening is formed.

  Furthermore, as a determination instrument, as shown in FIGS. 6C and 6D, a determination instrument may be formed by arranging cavities 78 having a long rectangular opening cross section in a layered manner. For example, in the determination instrument 80 shown in FIG. 6C, a plurality of cavities 78 are formed at predetermined intervals. Moreover, in the determination instrument 82 shown in FIG. 6D, the determination instrument has a cavity portion 78 (cavity portion 78A) in which the longitudinal direction of the cross-sectional opening extends along one direction, and a cavity portion 78 along a direction intersecting the one direction. (Cavity 78B) is formed.

  Even when such determination devices 70, 74, 80, 82 are used, the size (opening area, vertical and horizontal dimensions, etc.) and height (depth of the cavities 72, 76, 78) are appropriately set. By setting to, it is possible to accurately determine whether or not radiation has been irradiated at an appropriate angle (for example, whether or not proper bone mineral quantification is possible).

  Moreover, as a determination instrument, as shown in FIG. 7A, a determination instrument 86 in which a large number of cavities 84 having small opening areas are arranged in a matrix (vertically and horizontally) at regular intervals may be used. As shown in FIG. 7B, the determination image 88 formed by such a determination instrument 86 has a relatively large area of each high-concentration portion 90 when the radiation is appropriately irradiated. The average density of 88 is the highest. For example, if the opening area by the cavity 86 is ½ with respect to the area of the end face 86A of the determination tool 86, the density of the determination image 88 is half the solid density.

  On the other hand, in the determination tool 86, the determination image 88A, which is the determination image 88 when the radiation is irradiated obliquely, is a high concentration that becomes an individual high concentration portion 90, as shown in FIG. The area of the portion 90A is reduced, and thereby the average density of the determination image 88A is also reduced.

  From here, it can be determined from the density | concentration (average density | concentration) of the determination image 88 whether the radiation was irradiated from the appropriate direction.

  Furthermore, in this Embodiment, although the cavity part was formed as a radiation transmissive part, it is not restricted to this, You may fill with radiation transmissive materials, such as resin. That is, it may be formed in a block shape by wrapping or filling the periphery or hollow portion of a radiation transmitting portion formed in a column shape with a radiation transmitting material with a non-radiation transmitting member.

  Thereby, it is possible to form a determination instrument whose cross section is a character, a symbol, or various characters. At this time, for example, by using a character that does not have a symmetric straight line (not line symmetric), it is possible to prevent an error in the front and back of the captured image and an error in the orientation.

  FIG. 8 shows determination instruments 100 and 102 as an example. The determination instrument 100 is formed in a rectangular shape by surrounding the character block 104 having a cross section of L with a non-radiation transmitting material. Further, the determination instrument 102 is formed in a rectangular shape in which a hollow portion in the character block 106 having a cross section of R is filled with a non-radiation transmitting material and the periphery of the character block 106 is surrounded by the non-radiation transmitting material. .

  Accordingly, the determination instrument 100 determines whether or not an appropriate L-shape is formed in the captured image, and the determination instrument 102 determines whether or not an appropriate R-shape is formed in the captured image. Thus, in addition to whether or not radiation has been emitted from an appropriate direction, it can be determined whether or not the front and back sides and orientation of the captured image are appropriate.

  FIG. 9 shows a photographing instrument 108 using the determination instruments 100 and 102. In this imaging instrument 108, a reference tool 114 formed by standing up a restriction frame 112 at the peripheral edge of a band plate-like base 110, and a restriction frame 118 upright at the peripheral edge of the band plate-like base 116. And the instrument container 120 formed in the above manner. In the imaging instrument 108, the slope 40 is accommodated in the instrument container 120.

  For example, when imaging the hand 28 (the left hand 28L and the right hand 28R), the imaging device 108 configured in this way has the reference tool 114 on the back side and the longitudinal direction on the housing 24 of the cassette 22 in the left-right direction. Arrange along the direction. Further, the determination instrument 100 is disposed on the left side of the reference tool 114, and the determination instrument 102 is disposed on the right side. Furthermore, the instrument housing 120 that houses the slope 40 is arranged so that one end in the longitudinal direction thereof is the central portion in the longitudinal direction of the reference device 114 and the other end is on the near side.

  In this state, the left hand 28L and the right hand 28R, which are imaging parts, are arranged with the instrument container 120 interposed therebetween, and radiation is irradiated.

  In the captured image 122 obtained by imaging in this way, as shown in FIG. 10, a slope image 60 is formed between the image 56L of the left hand 28L and the image 56R of the right hand 28R, and further on the back side. A reference solid region 58 is formed. At this time, since the restriction frame 112 is formed on the reference tool 114 and the restriction frame 118 is formed on the instrument container 120, a part of the body of the subject 26 overlaps the solid region 58 and the slope image 60. The image will not be damaged.

  Further, determination images 124 and 126 by the determination instruments 100 and 102 appear on both sides of the solid region 58.

  Here, in the determination image 124 by the determination instrument 100, an L-shaped character image 128 appears corresponding to the character block 104, and in the determination image 126 by the determination instrument 102, an L-shaped character image 130 corresponding to the character block 106. Appears, it is obtained whether or not the radiation is irradiated at an appropriate irradiation angle depending on whether or not the character images 128 and 130 appear in an appropriate area, that is, an image that can be used for appropriate bone mineral quantification is obtained. It can be determined whether or not. Furthermore, in the photographed image 122, it can be accurately determined from the orientation of the character images 128 and 130 whether or not it has been mistakenly inverted.

  Accordingly, it is possible to accurately check whether or not the captured image 122 can be an appropriate diagnostic image by using the imaging instrument 108.

  On the other hand, depending on the imaging system 10 or the loading position of the cassette 22 in the imaging system 10, the radiation light source 18 may be biased with respect to the subject. For example, the left hand 28L side is irradiated with radiation substantially vertically, but the right hand 28R side may be irradiated with radiation at an angle.

  At this time, the determination instrument 100 is disposed on the left hand 28L side and the determination instrument 102 is disposed on the right hand 28R side, so that the determination result using the determination image 124 and the determination result using the determination image 126 are different. Arise.

  From this, when the determination image 126 is used, it is determined that the radiation irradiation angle exceeds the allowable range. However, when the determination image 124 is used, if the radiation irradiation angle is determined to be within the allowable range. The bone mineral content may be determined using the image 56L on the determination image 124 side.

  Further, in any of the determination images 124 and 126, when it is determined that the radiation angle exceeds the allowable range, the radiation direction (radiation angle α) is specified using the determination images 124 and 126. Then, the edge correction may be performed on at least one of the images 56L and 56R using the identification result, and the bone mineral quantity may be determined using the corrected image.

  In addition, this Embodiment demonstrated above does not limit the structure of this invention. For example, in the present embodiment, the left and right hands have been described as an example of the subject. However, the present invention is not limited to this, and the present invention is applicable to any subject that is a target for recording radiation image information on the stimulable phosphor sheet 14. can do.

  In addition, the present invention can be applied to any configuration in which radiation image information is recorded on the stimulable phosphor sheet 20 by radiation transmitted through the subject.

  Furthermore, in the present embodiment, the stimulable phosphor sheet 20 has been described as the radiation receiving medium. However, the present invention is not limited to this. For example, a radiation receiving element that receives radiation energy and converts it into an electrical signal is used. You may apply to the structure which uses the radiation light-receiving medium which arrange | positions a radiation light-receiving element in a line shape, and carries out scanning movement, or arrange | positions a radiation light-receiving element in a planar shape, and acquired a radiation transmission image.

10 Imaging system 20 Storage phosphor sheet (radiation receiving medium)
22 cassette 24 housing 30, 108 imaging device 32, 70, 74, 80, 82, 86, 100, 102 determination device (device body)
34, 72, 76, 78, 84 Cavity (radiation transmission part)
36, 88 Judgment image 38, 90 High density part 40 Slope (slope member)
46 Reference part (regulating member)
48 Instrument housing (regulating member)
52 Captured image 58 Solid area 60 Slope image 104, 106 Character block (radiation transmission part)
114 Reference tool (regulating member)
120 Instrument container (regulation member)

Claims (12)

An imaging instrument used for imaging a subject image that obtains the subject image from radiation irradiated on the radiation irradiation surface by irradiating the radiation irradiation surface of the radiation receiving medium with radiation including radiation transmitted through the subject. There,
A determination instrument main body formed by a non-radiation transmitting member and disposed opposite to the radiation irradiation surface together with the subject;
The determination instrument main body is formed on the determination instrument main body so as to reach the other end side from the one end side along the contact / separation direction with the radiation irradiation surface in a state of facing the radiation irradiation surface, and along the radiation irradiation surface. A radiation transmitting part having a constant cross-section in the direction and surrounded by the non-radiation transmitting member;
An imaging device including a determination device having Used to capture a subject image for acquiring the subject image from the radiation irradiated on the radiation irradiation surface by irradiating the radiation irradiation surface of the radiation receiving medium with radiation transmitted through the mounting surface on which the subject is placed. An imaging device,
A determination instrument body formed by a non-radiation transmitting member and disposed on the mounting surface;
The determination instrument main body is formed on the determination instrument main body so as to reach the other end side from one end side along the contact / separation direction with the mounting surface in a state where the determination instrument main body is disposed on the mounting surface. A radiation transmitting part having a constant cross-section in the direction and surrounded by the non-radiation transmitting member;
An imaging device including a determination device having   The imaging instrument according to claim 2, further comprising a regulation instrument that is framed in a long rectangular shape by a regulation frame made of a radiation transmitting member and disposed so as to protrude from the placement surface.   The transmission amount of the radiation is changed stepwise from one end side to the other end side in the longitudinal direction, is accommodated in the restriction frame of the restriction instrument, and is disposed on the mounting surface. The imaging device according to claim 3, comprising a slope member. On the mounting surface arranged opposite to the radiation irradiation surface of the radiation receiving medium,
A determination instrument main body formed by a non-radiation transmitting member and disposed on the placement surface, and the determination instrument main body disposed on the placement surface, along the contact / separation direction with the placement surface A radiation transmitting portion formed in the determination instrument main body so as to reach from the one end side to the other end side, having a constant cross-section in the direction along the mounting surface, and surrounded by the non-radiation transmitting member Arrange the imaging equipment including the judgment equipment,
In addition, the subject is placed on the mounting surface and irradiated with radiation,
A method for capturing a subject image, wherein the radiation transmitted through the subject and the imaging device is irradiated onto the radiation irradiation surface of the radiation receiving medium.   The imaging instrument is provided with a regulation instrument framed in a long rectangular shape by a regulation frame by a radiation transmitting member, and the regulation instrument is arranged so that the regulation frame protrudes from the placement surface, The subject image capturing method according to claim 5, wherein the subject image is captured.   The imaging instrument includes a slope member formed so that the amount of transmission of the radiation changes stepwise from one end side to the other end side in the longitudinal direction, and the slope member is the regulation of the regulation instrument. The subject image capturing method according to claim 6, wherein the subject image is captured in a frame. There is an imaging apparatus for acquiring the subject image from the radiation irradiated on the radiation irradiation surface by irradiating the radiation irradiation surface of the radiation receiving medium with radiation including radiation transmitted through the subject,
A determination instrument body formed by a non-radiation transmitting member and disposed on the mounting surface;
In a state where the determination instrument body is disposed on the mounting surface, the cross section in the direction along the mounting surface is constant, and the other end side from the one end side along the contact / separation direction with the mounting surface A radiation transmitting part formed in the determination instrument body so as to be surrounded by the non-radiation transmitting member so as to reach
An imaging device including a determination instrument having   The imaging apparatus according to claim 8, further comprising: a restricting instrument that is formed by being framed in a long rectangular shape by a restriction frame made of a radiation transmitting member, and arranged so that the restriction frame protrudes from the placement surface.   The transmission amount of the radiation is changed stepwise from one end side to the other end side in the longitudinal direction, is accommodated in the restriction frame of the restriction instrument, and is disposed on the mounting surface. The imaging device according to claim 9, comprising a slope member. A method for determining a subject image for determining suitability of the subject image captured by the subject image capturing method according to claim 5,
A cross-sectional area of the radiation transmitting member of the determination instrument along the placement surface is compared with a projected area of the radiation transmission member of the determination instrument formed on the radiation receiving medium. A method for determining a subject image, which determines whether or not the subject image to be formed is appropriate.   The subject image determination method according to claim 11, wherein the subject image is determined to be appropriate when a ratio of the transparent area to the cross-sectional area of the radiation transmitting member is within a preset range.