JP4057510B2 - X-ray CT system - Google Patents

Description

  The present invention relates to an X-ray CT apparatus, and more particularly to CT measurement of small animals used in animal experiments and the like.

  An X-ray CT apparatus is an apparatus that rotates an X-ray beam that passes through a specimen and reconstructs a tomographic image or a three-dimensional image of the specimen based on data obtained thereby. In addition to being used for diagnosing human diseases, the X-ray CT apparatus is also used for measuring animals and other objects other than the human body for the purpose of research and experiments. For example, in a pharmaceutical company, an X-ray CT apparatus is used to verify the results of animal experiments. In this case, examples of the specimen include small animals such as guinea pigs, rats, mice, hamsters, rabbits, dogs, and cats. In addition, a tissue piece separated from those small animals may be a specimen. Conventionally, when performing X-ray diagnosis of a small animal using an X-ray CT apparatus, for example, the specimen is simply placed on a horizontal bed.

  Patent Document 1 listed below discloses a veterinary X-ray imaging apparatus (so-called X-ray imaging apparatus) including a table having a simple V-groove on which an animal such as a dog is placed. In this device, the front and rear of the small animal are open. Patent Document 2 below discloses an industrial X-ray CT apparatus. According to this document, the enlarged projection image is obtained by rotating the sample side and changing the distance between the X-ray generator and the sample. In this apparatus, the sample to be measured is an industrial product and not a living body. Further, the sample is measured in a bare state.

JP 2001-299786 A JP-A-5-322802

  Conventionally, CT measurement is performed for each specimen. Therefore, when performing CT measurement on a large number of specimens, it is necessary to exchange the specimens to be measured at regular time intervals, that is, artificial replacement work occurs repeatedly, and other work is interrupted repeatedly. As a result, problems such as a decrease in measurement efficiency or an increase in human burden have arisen.

  As can be seen in the above-mentioned conventional X-ray CT apparatus, if the measurement is performed simply by placing the small animal on the horizontal bed, it is very difficult to position and hold the small animal. If positioning is not appropriate, there is also a problem that a part of a small animal's body protrudes from the effective visual field. Also, if the small animal moves during the measurement, the image quality is significantly reduced. In addition, when the hair or tail of a small animal comes into contact with a gantry or other mechanism, hygiene problems are likely to occur. Furthermore, when the excrement of small animals, fallen hair, etc. (that is, filth) is released to the outside, sanitary problems occur as described above. One or more of these problems can be pointed out for subjects other than small animals in some cases. In addition, it is required to solve one or more of these problems.

  An object of the present invention is to enable CT measurement of a plurality of specimens collectively.

  Another object of the present invention is to improve CT measurement efficiency for a plurality of specimens.

(1) The present invention includes a measurement unit that forms an X-ray beam in a direction that intersects the direction of the rotation center axis, and a plurality of specimens that are arranged in an array that intersects the direction of the rotation center axis. A container for accommodating a sample set, a moving mechanism for moving the container relative to the measurement unit in the direction of the rotation center axis, and the measurement unit relative to the container around the rotation center axis And a data processing means for managing measurement data for each sample in the container and processing each measurement data.

  According to the above configuration, the container accommodates a sample set including a plurality of samples to be measured. The sample set is composed of a plurality of samples arranged in parallel, and measurement data (for example, CT images) can be obtained for a plurality of samples at the same time by one CT measurement. Here, a CT image (entire CT image) formed by one CT measurement includes tomographic images (partial CT images) of a plurality of specimens. Thus, for example, the size of a partial CT image is smaller than in a normal case, and the resolution of a partial CT image may be lower than in a normal case. There is an advantage that a plurality of specimens can be measured simultaneously. Further, it is possible to eliminate the labor and time loss of sample exchange and perform efficient measurement. Since each measurement data is separated and managed for each sample, the measurement data for each sample can be easily used.

  The sample set includes, for example, two samples (or sample rows) arranged on the left and right, four samples (or sample rows) arranged on the top, bottom, left and right, three samples (or sample rows) arranged on an equilateral triangle, etc. Configured as If an array crossing the rotation center axis (container center axis) is employed, a plurality of specimens can be measured simultaneously, and various arrays can be employed.

  In addition, since each specimen is accommodated in the container, it is possible to avoid a problem that occurs when the specimen is measured by stripping. Each specimen may be a small animal such as a mouse or a tissue separated from the small animal. In the above moving scanning, the container or the measurement unit may be driven, or both may be moved relative to each other. The same applies to the rotational scanning described above. Further, the moving scan may be continuous or intermittent. Usually, moving scanning is performed to cover the entire container or sample row, but in some cases, moving scanning may be performed only in a part of the range. The container may be placed in a horizontal state or a vertical state.

  Preferably, the container includes a partition member that partitions the internal space into a plurality of partial spaces, and the plurality of partial spaces are formed in parallel in an array crossing the rotation center axis, and each of the partial spaces includes at least Contains one specimen. The specimens can be spatially separated by the partition member to prevent mutual contact. Further, if the coordinate information of each partial space is known, it is easy to cut out an image of the specimen in each partial space.

  Desirably, the partition member has an assembly structure including a plurality of partition plates. According to this configuration, the specimen and the partition plate can be set in stages when a plurality of specimens are accommodated in parallel.

  Desirably, at least one of the plurality of partial spaces accommodates a specimen row composed of a plurality of specimens arranged vertically in the direction of the rotation center axis.

  Preferably, the container includes a plurality of partial spaces formed in parallel in an array intersecting the rotation center axis, and a first storage unit that stores the sample set, and the rotation center with respect to the first storage unit. And a second housing portion that is continuous in the axial direction and has a space larger than each of the partial spaces. According to this configuration, a plurality of specimens having different sizes can be measured together.

(2) The present invention also provides a measurement unit that forms an X-ray beam in a direction that intersects the direction of the rotation center axis, and a plurality of specimens that are arranged in an array that intersects the direction of the rotation center axis. A container that contains a sample assembly, a moving mechanism that moves the container relative to the measurement unit in the direction of the rotation center axis, and the measurement unit about the rotation center axis with respect to the container Data for creating and managing a partial CT image for each specimen by performing specimen separation processing on the entire CT image acquired at each measurement position in the direction of the rotation center axis and a rotation mechanism that rotates relatively And a processing means.

  According to the above configuration, a plurality of specimens are simultaneously measured, and a partial CT image for each specimen is separated and generated from the entire CT image obtained thereby. Therefore, there is an advantage that a plurality of samples can be measured in one sample measurement time.

  Preferably, the container includes a partition member that partitions the internal space into a plurality of partial spaces, and the plurality of partial spaces are formed in parallel in an array that intersects the rotation center axis, In this process, an image area corresponding to each partial space is cut out from the entire CT image as the partial CT image.

  Preferably, a measurement section setting means for setting one or a plurality of measurement sections in the direction of the rotation center axis is included. In setting the measurement section, it is desirable to use a scout image, and one or a plurality of measurement sections (scan sections) are automatically set on the scout image by user designation or using image processing such as edge detection. .

(3) Further, the present invention is a hollow container that is set with respect to the X-ray CT apparatus and accommodates a plurality of specimens as small animals or tissues separated therefrom, and is in the direction of the central axis of the container It has a cross-sectional size capable of accommodating a specimen set composed of a plurality of specimens arranged in an intersecting arrangement, and is configured to be transparent or all or partly configured.

  Desirably, it has a partition member which partitions the interior space of the container into a plurality of partial spaces, and the plurality of partial spaces are formed in parallel in an array crossing the rotation center axis.

  The above-mentioned small animals are animals belonging to relatively small mice used for pharmaceutical experiments, for example. By wrapping all of them, problems such as contact of small animals (for example, their tails and hairs) with the device and outflow of excreta can be solved. The container is preferably configured as a cylindrical shape. Since the effective field of view on which the CT measurement can be performed on the beam scanning plane is also circular, compatibility with CT measurement is good if the shape is cylindrical. Moreover, if a part or all is transparent, an internal small animal can be observed also during a measurement, and the state can be confirmed. It is desirable to provide an air hole or an anesthetic gas introduction hole in the container.

  The container can be removed from the main body of the X-ray CT apparatus, and the operability is good. It is also convenient when cleaning the container. Furthermore, the container may be disposable. In a state where the sample is accommodated in the container, the sample is restrained by the fixing member. Thereby, problems such as image blurring and image blurring in CT measurement can be prevented. Further, since the surface of the specimen is separated from the inner surface of the container by the arrangement of the fixing member, there can be obtained an advantage that, for example, the fat layer and the container can be easily separated in the CT image in data processing. As the fixing member provided around the specimen, a clogging member such as urethane, sponge, air packing, gauze, or the like can be used.

  As described above, according to the present invention, a plurality of specimens can be collectively measured by CT, which is efficient.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows an example of an X-ray CT apparatus. This X-ray CT apparatus is an apparatus for performing CT measurement particularly on mice such as mice, rats, mice, guinea pigs and hamsters. This X-ray CT apparatus is roughly divided into a measurement unit 10 and a calculation control unit 12.

  The measurement unit 10 has a main body 16 having a gantry 18. An opening is formed in the upper surface 16A of the main body 16, and an arm 26 projects upward from the opening. The arm 26 forms a part of a slide mechanism described later. The arm 26 is connected to a container 24 described later, and slides (moves and scans) it in the direction of the rotation center axis.

  On the other hand, measurement units (X-ray generator, X-ray detector), which will be described later, are accommodated in the gantry 18 and rotate around the rotation center axis. A hollow portion 18A is formed in the central portion of the gantry 18 in the direction of the rotation center axis. The hollow portion 18A is a non-penetrating type, but may be a penetrating type.

  In the present embodiment, the container 24 is a capsule for storing a plurality of specimens (small animals, tissues extracted from the same) in parallel (with an array orthogonal to the rotation center axis), and the container 24 is the present embodiment. The container has a substantially cylindrical shape, and is arranged in a state where its container central axis coincides with the rotation central axis. Specifically, the base end portion 76 of the container 24 is detachably attached to the upper end portion of the arm 26 described above. In this case, examples of the attachment / detachment mechanism include various engagement mechanisms or screwing mechanisms. As described above, the container 24 has a hollow cylindrical shape, and a plurality of small animals are arranged inside the container 24 in this embodiment. With such a configuration, the hair of the small animals is directly attached to the gantry 18. Can be prevented from touching. In addition, it is possible to prevent the problem that small animal excrement or detached hair is released to the outside. Further, as will be described later, since it becomes possible to restrain the small animal in a fixed manner, it is possible to prevent problems such as image blurring when the CT image is reconstructed. It is desirable to prepare and selectively use a plurality of types of containers having different sizes and shapes.

  After the container 24 is attached to the arm 26, the arm 26 is driven forward along the direction of the rotation center axis, whereby the container 24 is inserted into the cavity 18A of the gantry 18. At this time, the container 24 is positioned so that the X-ray beam is set at a predetermined position in the specimen. Further, such a measurement position is changed continuously or stepwise.

  An operation panel 20 is provided on the upper surface 16A of the main body 16, and the operation panel 20 includes a plurality of switches, indicators, and the like. Using this operation panel 20, the user can operate the operation of the apparatus at the measurement site. A plurality of casters 22 are provided below the main body 16. Incidentally, the height of the measurement unit 10 is, for example, 100 cm.

  Next, the arithmetic control unit 12 will be described. The arithmetic control unit 12 is electrically connected to the measurement unit 10 by a cable 14. The measurement unit 10 and the calculation control unit 12 may be provided in the same room, or may be installed in different places. The arithmetic control unit 12 is configured by a normal computer system or the like, and specifically includes a processor 30, a display 32, a keyboard 36, a mouse 38, a storage device 34, a printer 40, and the like. The operation control unit 12 controls the operation of the measurement unit 10, and a CT image is configured based on data transmitted from the measurement unit 10. This CT image usually corresponds to a two-dimensional tomographic image, but a three-dimensional image may be constructed. Incidentally, in the apparatus of the present embodiment, the rotation speed of the measurement unit in the gantry 18 is, for example, 10 rotations per minute. Of course, such a rotation speed can be appropriately set according to the application.

  FIG. 2 is a block diagram showing the configuration of the X-ray CT apparatus shown in FIG. An X-ray generator 52 is provided on one side and an X-ray detector 60 is provided on the other side with the rotation center axis O therebetween. A collimator 54 is provided on the irradiation side of the X-ray generator 52. The X-ray generator 52 generates a divergent or fan-shaped (here, fan-beam shaped) X-ray beam 56 as shown. On the other hand, the X-ray detector 60 is configured as a plurality of (for example, 100) X-ray sensors arranged in a line, and an X-ray receiving opening is set according to the opening angle of the X-ray beam 56. Incidentally, the arrangement of the plurality of X-ray sensors may be linear or arcuate.

  In FIG. 2, a high voltage source used with the X-ray generator 52, a data processing circuit used with the X-ray detector 60, and the like are not shown.

  In FIG. 2, reference numeral 58 denotes an effective field of view. This is a circular area in which a CT image can be formed when the X-ray beam 56 is rotated and scanned. Incidentally, the effective visual field 58 is determined according to the positional relationship between the X-ray generator 52 and the X-ray detector 60 and the specimen or the rotation center axis. In this embodiment, since the displacement mechanism 62 is provided, it is possible to change the positional relationship between them and mechanically vary the magnification of the CT image.

  That is, the X-ray generator 52 and the X-ray detector 60 are connected to the displacement mechanism 62, and the displacement mechanism 62 maintains the distance between the X-ray generator 52 and the X-ray detector 60. (That is, the measurement unit) has a function of displacing in the beam axis direction of the X-ray beam 56. In this case, the rotation center axis O is not changed, that is, the magnification can be changed by moving the measurement unit without moving the container described above. The displacement mechanism 62 includes a motor 62A for generating a displacement force.

  The gantry rotation mechanism 66 is a mechanism that rotates the entire base including the displacement mechanism mounted thereon by rotating the rotation base. Since the measurement unit is mounted on the displacement mechanism 62, the measurement unit positioned at a desired position by the displacement mechanism 62 is rotationally driven while maintaining the position. The gantry rotating mechanism 66 has a motor 66A for generating the driving force.

  The slide mechanism 68 is a moving mechanism that slides the arm 26 shown in FIG. 1, and the driving force is generated by the motor 68A. The operation panel 20 is provided on the upper surface of the main body as described above. The operation panel 20 may be connected to a local controller (not shown) provided on the measurement unit 10 side so that the local controller and the arithmetic control unit 12 communicate with each other.

  Incidentally, although various mechanisms 62, 66, 68, etc. are shown in FIG. 2, it is desirable to provide a sensor to detect a position or a change by these mechanisms. Then, it is desirable that the arithmetic control unit 12 performs so-called feedback control based on the output signals of those sensors. The magnification change by the displacement mechanism 62 may be performed by user input. For example, the subject size or the container size is automatically detected, and the magnification is automatically set based on the detected data. Also good. Furthermore, when the container type or the like is registered in advance, the magnification may be set using the registered information. Further, in the example shown in FIG. 2, the slide mechanism 68 has the motor 68A as a drive source, but the slide force may be generated artificially.

  Next, the arithmetic control unit 12 will be described. As described above, the display unit 32, the storage device 34, the keyboard 36, the mouse 38, the printer 40, and the like are connected to the processor 30. In addition, a communication unit 42 for communicating with an external device via a network is connected.

  The processor 30 includes a CPU and various programs. FIG. 2 shows typical functions. The processor 30 includes an operation control unit 44, a reconstruction calculation unit 46, a scout image forming unit 200, a section setting unit 202, and a data management / processing unit 204. ing.

  The operation control unit 44 controls the overall operation of the measurement unit 10. The reconstruction calculation unit 46 executes a calculation for forming a CT image based on a lot of data obtained by rotational scanning of the X-ray beam. In this case, a three-dimensional image may be constructed. Various known methods can be used for the reconstruction operation. Note that, in changing the magnification described above, the arithmetic expression used in the reconstruction calculation can be basically used as it is. However, when a special variable magnification method is applied, a part of the reconstruction calculation expression may be changed as necessary.

  The scout image forming unit 200 forms a scout image prior to CT measurement for a plurality of specimens. Specifically, the container containing a plurality of specimens is moved and scanned by the slide mechanism 68 without rotating the measurement unit 10, and X-ray measurement is performed by the measurement unit 10 at that time. Based on the detection data thus obtained, a scout image as a two-dimensional transmission image such as an X-ray photograph is formed. This scout image is formed in order to set a section for defining a CT scan range for each specimen.

  The section setting unit 202 sets one or a plurality of CT scan ranges (CT measurement ranges) in the rotation center axis direction according to user settings or automatically. In the case of the user setting, a scout image is displayed on the display 32, and each sample set (four samples arranged in the vertical and horizontal directions as will be described later in this embodiment) is visually determined on the scout image using the mouse 38. A section for performing a CT scan is set. In the case of automatic setting, both ends of each sample set are individually recognized by image processing (for example, edge detection method) of the scout image, and the interval for performing the CT scan so as to cover all the main parts or the main part is automatically set. Is set automatically. This will be described in detail later. In any case, a CT scan range is set by the section setting unit 202, and the operation control unit 44 performs operation control during CT measurement according to the setting.

  In addition, according to the above section setting, measurement can be skipped for the CT scan unnecessary range between sample sets, and the measurement time for a plurality of samples as a whole can be shortened, which is efficient. When the range of each specimen set is known or separately registered, formation of a scout image and measurement for it are not necessary. In addition, without setting the section, a large number of CT images may be acquired for the entire container for the time being, and unnecessary CT images may be removed automatically or by user designation.

  The data management / processing unit 204 performs a separation process on the CT image formed by the reconstruction calculation unit 46, manages an image separated in association with each specimen, and also provides a necessary image for each image. It is a means for performing processing. That is, in this embodiment, as will be described later, four specimens can be arranged in a vertical plane in a container, and CT measurement can be performed on them simultaneously, and individual CT images (total CT images) obtained thereby can be measured. ) Is separated into partial CT images for each specimen, and each partial CT image is associated with each specimen. On the storage device 34, a plurality of partial CT images associated with the specimen identifier or a plurality of images after image processing thereof are stored. Here, the identifier (identification information) of each sample is input by the input means. In this case, the user may be input using the keyboard while being associated with the eight specimen positions, or may be input from the outside. In addition, identification information may be provided for each specimen in some manner and automatically read.

  A scout image and a CT image are displayed on the display 32. For example, when displaying a CT image, it is desirable to display a numerical value representing a magnification (enlargement ratio) or a scale. According to this configuration, the size of the object can be evaluated when the image is visually determined. That is, for example, the amount of fat and the size of a tumor can be determined quantitatively.

  FIG. 3 is a perspective view of the container 24 shown in FIG. The container 24 has a cylindrical shape that extends in the moving direction (rotation central axis direction) 205 and has a large cross-sectional size. The container 24 is roughly divided into a container main body 70 and a lid 72. A distal end portion 74 is provided on the distal end side of the container body 70, and the distal end portion 74 forms a flat vertical wall or has a conical shape protruding forward. A through-hole for introducing air or anesthetic gas is formed in the center of the distal end portion 74 as necessary. A proximal end portion 76 is provided on the proximal end side of the container body 70. A through hole may also be formed in the base end portion 76. As described above, the base end portion 76 is a portion to be mounted on the slide mechanism, but the mounting mechanism is not illustrated. As shown in the figure, when the container 24 is arranged in a horizontal state, filth and the like excreted from the small animals are stored inside the container body 70, and can be prevented from flowing out to the outside. Further, it is possible to prevent the detached hair from coming out.

  An opening 70A is formed in the container body 70, and the lid 72 described above is provided in the opening 70A. The lid 72 may be opened and closed by, for example, a hinge, or may simply be attached to the container body 70 on one side with an adhesive tape or the like, or completely with respect to the container body 70. A configuration in which the lid 72 is separated may be used. In any case, it is desirable that a plurality of small animals can be easily stored in the container body 70. Incidentally, the container 24 is formed of a transparent X-ray transmitting member as a whole. Examples of the material include resins such as acrylic and ABS. As long as internal observation can be performed, only a part may be transparent.

  In the example shown in FIG. 3, the container 24 has a hollow and substantially cylindrical shape as a whole, but other shapes may be adopted. For example, a rotationally symmetric shape around the central axis can be mentioned, and further, an elliptical section, a D-type section, or a quadrangular section can be listed. Considering that the effective field of view 58 shown in FIG. 2 is circular, and considering that a plurality of specimens are arranged in parallel, it is desirable that the cross section of the container 24 be circular, that is, the shape of the container It is desirable to adopt a cylindrical shape. Incidentally, in the example shown in FIG. 1, the container 24 is set in a horizontal state. However, for example, the container 24 may be set in a standing state. In the example shown in FIG. 3, the length of the container 24 is 300 mm, for example, and the diameter (outer diameter) is 120 mm, for example.

  FIG. 4 is a perspective view showing a state where a plurality of small animals are accommodated in the container 24. In the present embodiment, a sample set consisting of a total of eight samples (small animals) is accommodated in the container 24 at the same time. The sample set is composed of four sample rows, and these sample rows are arranged in an array perpendicular to the direction of the rotation center axis, specifically, in an up / down / left / right arrangement. In this example, each sample row is composed of two samples arranged in the direction of the rotation center axis. From another point of view, the sample set is composed of two sample sets arranged in the direction of the rotation center axis, and each sample set is composed of four samples arranged vertically and horizontally.

  A partition member (separator) 300 is provided in the container 24. The partition member 300 includes a fixed vertical plate 302 extending in the direction of the rotation center axis, and a three-plate 304 as a detachable member, and is configured as an assembly thereof. The triple plate 304 includes a pair of horizontal plates 304B and 304C such as horizontal wings, and a vertical plate 304A such as a vertical wing formed upright from the central portion thereof. The lower end of the vertical plate 304A protrudes downward beyond the level of the pair of horizontal plates 304A and 304B, and a concave portion 304D is formed in the protruding portion. The recess 304D is fitted to the upper side of the fixed vertical plate 302 when the three-plate 304 is mounted in the container 24. In that state, the partition member 300 has a cross-shaped vertical cross section.

  Therefore, when the partition member 300 is provided in the container 24, the internal space of the container 24 is divided into four partial spaces arranged vertically and horizontally, and one or a plurality of specimens are arranged in each partial space. FIG. 4 shows a state in which two specimens 84 are accommodated in each of the two lower partial spaces. After arranging the four specimens in the lower part of the container 24 in this way, as shown in FIG. 5, the three plates 304 are set and then two in each of the two partial spaces formed in the upper part of the container 24. A specimen 84 is accommodated. Then, by closing the lid 72, the arrangement of a total of eight specimens 84 is completed.

  With the partition member 300, the specimens 84 are arranged apart from each other in the vertical plane. For this reason, the sample can be kept as it is without being compressed more than necessary, and the data of each sample can be easily separated. The partition member 300 is preferably made of a member that does not attenuate X-rays as much as possible, and has at least an X-ray attenuation rate different from that of the soft tissue or fat (and the container 24 as necessary) of the specimen. It is desirable to use

  Since CT images become unclear when each small animal moves during measurement, it is desirable that a fixing member that hardly attenuates X-rays is accommodated in the container 24 and each specimen 84 is fixed by the fixing member. In this case, examples of the fixing member include an elastically deformable sponge body, an air packing, an adhesive sheet, and a clogging member (such as gauze).

  As described above, it is configured so that a plurality of samples can be accommodated in a container, and after performing CT measurement on a plurality of samples at the same time, data management is performed for each sample, each sample is measured individually. Compared to the case, the number of specimens processed per unit time can be increased, and efficient measurement can be realized. In addition, since the synchronization of measurement can be achieved, for example, the problem of measurement time difference for a plurality of samples after drug administration can be solved. Depending on the size and number of specimens accommodated in the container, the partition structure in the container may be varied.

  According to the above fixing member, the movement of the small animal 84 can be prevented, and the surface of the small animal 84 can be separated from the inner surface of the container 24, so that an advantage in data calculation is also obtained. That is, when the container material has an X-ray absorption coefficient equivalent to the fat or muscle of the small animal 84, if the small animal 84 is in contact with the inner surface of the container, the container itself is a part of the small animal. As such, there is a risk of being mistaken for data calculation. On the other hand, by inserting a material having a different X-ray absorption coefficient between the small animal 84 and the container 24 (the same applies to the partition member), the two are discriminated on the image, and the above-mentioned misperception is made. It becomes possible to prevent.

  The number of specimens arranged in the direction of the rotation center axis in the container 24 is arbitrary, but when arranging a plurality of specimens, a separator (partition plate) is also provided in order to separate the specimens adjacent in the direction of the rotation center axis. ) May be provided. Moreover, you may make it provide such a separator with the tail insertion part which accommodates the tail of a small animal.

  FIG. 6 shows a scout image acquired prior to CT measurement. In the figure, the X direction is the container center axis direction (first horizontal direction), and the Y direction is the direction orthogonal to the X direction (second horizontal direction). As already described, this scout image is acquired by fixing the X-beam irradiation direction, for example, vertically without rotating the measurement unit in the gantry, and moving and scanning the container on the X-ray irradiation direction. In FIG. 6, four specimen images 84A are shown, but actually, there are four specimens in the same arrangement under the four specimens (in order to simplify the drawing content in FIG. 6). They are not shown in the figure).

  When the CT measurement section is set for each specimen set (four specimens arranged vertically and horizontally) by manual setting, for example, on the screen on which the scout image is displayed, the section 310A in the X direction using a pointing device or the like by the user. , 310B is designated. For the Y direction, the measurement width 312 can be designated based on the inner diameter of the container in advance.

  On the other hand, when the sections 310A and 310B are automatically set, image analysis is performed on the scout image, and the sections 310A and 310B are set from the image analysis result. Specifically, in each X coordinate, the Y direction is set as a search direction, and an evaluation value, specifically, a maximum pixel value (maximum pixel value) is searched along the Y direction. The distribution of the maximum pixel value is shown in FIG. Two independent trapezoidal or mountain-shaped waveforms are generated corresponding to each sample set, and if a threshold value T is set for the distribution, the rising and falling coordinates of each waveform are used as the coordinates crossing it. Can be automatically identified. In this way, the sections 310A and 310B are determined.

  FIG. 8 shows a cross section of the container 24. A partition member 300 having a cross shape is disposed in the container 24, and the internal space of the container 24 is divided into four partial spaces. A specimen 316 is arranged in each partial space. One CT image (entire CT image) is formed by one rotation scanning of the measurement unit, and the CT image includes four specimen cross sections (partial CT images). Although it is possible to manage the CT image as it is, in the present embodiment, image processing for separating each of the four specimen sections is performed. In that case, four sector-shaped cutout areas 320 are set, and four partial CT images are cut out from the entire CT image accordingly. In this case, as long as the target specimen portion is sufficiently covered, each cut-out area may have a circular shape or other shapes instead of the sector shape.

  FIG. 9 shows another embodiment of the container as a cross-sectional view. The container 322 has a cylindrical shape as a whole and includes a main body 321 and four lids 326. In the main body 321, a specimen storage chamber 324 having a circular cross section is formed at four positions on the top, bottom, left, and right by an internal partition structure. Each specimen storage chamber 324 is provided with a lid 326 that can be opened and closed. That is, the sample can be taken in and out individually for each sample storage chamber 324 by opening the lid 236. Further, since the sample storage chamber 324 is a cylindrical space, it is easy to store a small animal or the like, and it is also easy to fix with a fixing member. On the other hand, a dead space is likely to occur. Even when such a container 300 is used, CT measurement can be simultaneously performed on a plurality of specimens.

  Next, the operation will be described with reference to FIG. After a plurality of specimens are accommodated in a predetermined arrangement in the container and the lid of the container is closed, the container is set in the measurement unit. In S101, the container is moved and scanned, whereby a scout image is acquired. In S102, it is determined whether the manual designation mode or the automatic designation mode is selected, and when the user selects the former, a measurement section is designated for each sample set on the scout image in S110. When the latter is selected, 0 is given to X as an initial setting in S104. Next, in S105, the pixel value of each pixel is referred to along the Y direction in the X coordinate, and the maximum pixel value is determined from among them. Px is specified. In S106, it is determined whether the maximum pixel value Px crosses the threshold value, that is, exceeds or falls below. If yes, the X value at that time is used as the X coordinate of the end point (the tip X coordinate or the tail end X coordinate). Saved. Then, in S108, it is determined whether or not X has reached the maximum value. If it has not reached, X is incremented by 1 in S109, and each process from S105 is repeated again. Finally, each section is set.

  When it is determined in S108 that X has reached the maximum value, or when the process of S110 is completed, CT measurement is executed for each section in S111, that is, CT measurement is executed for the sample set, A plurality of (for example, 40) CT images are acquired at a predetermined pitch for each specimen set. In this case, the identification code of each specimen is read as necessary. In S112, a partial CT image for each sample is cut out from the entire CT image, the image is managed for each sample, and the image is processed as necessary. According to the above, it is efficient because a plurality of samples can be measured simultaneously, and data management for each sample can be performed reliably. The user can also perform other operations during a series of CT measurements.

  In the above embodiment, the entire small animal is the measurement target, but a part of the small animal tissue (for example, the lumbar spine) may be the measurement target. In that case, a measurement section or an image configuration area is set so that the partial tissue is covered. Moreover, you may make it accommodate as a specimen the extracted bone, the extracted brain, etc. which were extracted from the small animal. In the above embodiment, eight specimens are accommodated in the container, but the invention is not limited to this.

  FIG. 11 shows a modification. In this example, the container 330 includes a first storage portion 330A and a second storage portion 330B. A partition member 334 having a cross-shaped cross section is disposed in the first accommodating portion 330A, that is, four partial spaces are configured. Accordingly, eight small animals 338 are accommodated in the first accommodating portion 330A. The second accommodating portion 330B has a single accommodating space in which a slightly large medium-sized small animal 336 can be accommodated. Thus, if the cross-sectional size of the storage space is made different between the first storage unit 330A and the second storage unit 330B, there is an advantage that a plurality of specimens having different sizes can be CT-measured together.

  In the embodiment shown in FIG. 3 and the like, a total of eight specimens are accommodated at the same time. Of course, only four specimens arranged in the vertical and horizontal directions may be accommodated, or two specimens are arranged side by side. It may be arranged. In addition, there are various other modes of parallel arrangement of a plurality of specimens.

1 is a perspective view showing an overall configuration of an X-ray CT apparatus according to the present invention. 1 is a block diagram showing an overall configuration of an X-ray CT apparatus according to the present invention. It is a perspective view of the container which accommodates a some sample side by side. It is a perspective view for demonstrating the internal structure of a container. It is a perspective view which shows the state which accommodated eight specimens in the container. It is a figure for demonstrating the setting of the measurement area in a rotation center axis direction. It is a figure for demonstrating automatic area setting. It is a figure for demonstrating the process which cuts out four partial CT images from a whole CT image. It is sectional drawing for demonstrating the structure of the container which concerns on other embodiment. It is a flowchart for demonstrating operation | movement of a X-ray CT apparatus. It is a schematic diagram which shows the structure of the container which concerns on other embodiment.

Explanation of symbols

  10 measurement units, 12 calculation control units, 24 containers, 44 operation control units, 46 reconstruction calculation units, 200 scout image forming units, 202 section setting units, 204 data management / processing units.

Claims (5)

A measuring unit that forms an X-ray beam in a direction intersecting the direction of the central axis of rotation;
A container for storing a sample set composed of a plurality of samples arranged in an array crossing the direction of the rotation center axis;
A moving mechanism for moving the container relative to the measurement unit in the direction of the rotation center axis;
A rotation mechanism for rotating the measurement unit relative to the container around the rotation center axis;
Scout image forming means for forming a scout image of the sample set prior to CT measurement of the sample set;
A measurement section setting means for setting one or a plurality of CT measurement sections in the direction of the rotation center axis by user designation on the scout image or by image processing based on the scout image;
A specimen separation process is performed on an entire CT image representing a cross section of the specimen set acquired in the one or a plurality of CT measurement sections, and a partial CT image for each specimen constituting the specimen set is created. Data processing means to manage ;
X-ray CT apparatus characterized by including. The apparatus of claim 1.
The container has a partition member that partitions the internal space into a plurality of partial spaces,
The plurality of partial spaces are formed in parallel in an array intersecting the rotation center axis,
Each X-ray CT apparatus is characterized in that each partial space contains at least one specimen. The apparatus of claim 2.
An X-ray CT apparatus characterized in that at least one of the plurality of partial spaces accommodates a specimen row composed of a plurality of specimens arranged vertically in the direction of the rotation center axis. The apparatus of claim 1.
The container is
A plurality of partial spaces formed in parallel in an array crossing the rotation center axis, a first storage unit for storing the sample set;
A second housing portion that is continuous in the direction of the rotation center axis with respect to the first housing portion and has a space larger than each of the partial spaces;
X-ray CT apparatus characterized by including. The apparatus of claim 1 .
The container has a partition member that partitions the internal space into a plurality of partial spaces,
The plurality of partial spaces are formed in parallel in an array intersecting the rotation center axis,
The X-ray CT apparatus, wherein the specimen separation process is a process of cutting out an image region corresponding to each partial space from the entire CT image as the partial CT image.

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