JP4720300B2 - Tomography equipment - Google Patents

Description

  The present invention relates to a tomographic apparatus used in the medical field, industrial fields such as non-destructive inspection, RI (Radio isotope) inspection, and optical inspection.

  Conventionally, as this type of apparatus, an X-ray tube and a flat panel X-ray detector (hereinafter referred to as “FPD” as appropriate) arranged opposite to each other are connected to a tomographic axis (main scanning axis) passing through a region of interest of a subject. Also referred to as a main scan that rotates integrally around the X-ray tube, and the FPD are integrated around one axis (also referred to as a secondary scan axis, hereinafter referred to as “body axis”) that is substantially perpendicular to the tomographic axis. Subordinate scanning is performed. Then, a three-dimensional tomographic image is acquired based on a group of projection data obtained from the FPD at each time point of main scanning and sub scanning.

  As shown in FIG. 20, the FPD 153 rotated by the main scanning mechanism 151 and the sub-scanning mechanism 152 is processed with a power supply unit 154 for power supplied to the FPD 153 and projection data (also referred to as a detection signal) obtained from the FPD 153. The image processing unit 155 is fixedly provided. Therefore, a twist occurs between the FPD 153 and the power supply unit 154 or the image processing unit 155. Therefore, power is supplied from the power supply unit 154 to the FPD 153 via the slip ring mechanism 156. For transmission of projection data from the FPD 153 to the image processing unit 155, an optical isolation method using a pair of optical transmission units 157 and an optical reception unit 158 is used (see, for example, Patent Document 1).

JP 2004-141656 A

However, the conventional example having such a configuration has the following problems.
The life of the slip ring mechanism is limited because it deteriorates and is damaged by wear. Moreover, if a slip ring mechanism, an optical transmitter, and an optical receiver are provided, the cost increases.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a tomographic apparatus capable of performing main scanning in a state where a flexible cable is fixedly connected to a detection means. .

In order to achieve such an object, the present invention has the following configuration.
In other words, the invention according to claim 1 is configured such that an irradiation source for irradiating a subject with electromagnetic waves and a projection data of the subject from the electromagnetic waves that are disposed opposite to the irradiation source with the subject interposed therebetween and transmitted through the subject. The irradiation source and the irradiation source and the irradiation source and the detection unit to be obtained are rotated around the tomographic axis while being inclined at a predetermined angle with respect to the tomographic axis passing through the region of interest of the subject. Main scanning means for performing main scanning for moving the detection means around the tomographic axis, and performing reconstruction processing based on a group of projection data obtained from the detection means at each time point of main scanning. In the tomography apparatus for acquiring a tomographic image, the detection surface of the detection unit is non-rotated around an axis parallel to the tomographic axis during main scanning, and passes through the center of the detection surface. In-plane, with 1 in-plane Comprising a first rotating means for rotating the detection surface about the axis, the first rotating means, characterized in that rotating the detection surface according to the displacement amount from the sectional axis of said detection means is there.

[Operation / Effect] According to the invention described in claim 1, during the main scanning, the detection surface of the detection means is not rotated about the axis parallel to the tomographic axis, and thus moves in parallel around the tomographic axis. . Thereby, in the main scanning, the relative positional relationship between the detection means and the other static (fixed) object is not twisted. Therefore, the main scanning can be performed in a state where the flexible cable is fixedly connected to the detection means.
Further, by providing the first rotation means, the detection surface of the detection means can be inclined according to the amount of displacement from the tomographic axis.

The invention according to claim 2 is the tomography apparatus according to claim 1 , wherein the axis in the detection plane perpendicular to the one axis in the plane at the center of the detection plane is two axes in the plane. A second rotating means for rotating the detection surface about two in-plane axes, the second rotating means rotating the detection surface in accordance with a displacement amount of the detection means from the tomographic axis. It is a feature.

[Operation / Effect] According to the invention described in claim 2, by providing the second rotating means in addition to the first rotating means, the detection surfaces of the detecting means can be inclined in two orthogonal directions. it can.

According to a third aspect of the present invention, in the tomography apparatus according to the second aspect, the main scanning means rotates the holding rod along a predetermined circular orbit around the tomographic axis, and the holding A support member joined to the rod via a bearing and supporting the detection means, and a regulation means for regulating rotation of the support member around the bearing are provided .

[Operation / Effect] According to the invention described in claim 3 , preferably, the detection surface of the detection means is parallel to the tomographic axis by including the restriction means for restricting the rotation of the support member around the bearing. It can be non-rotating around the axis. Thereby, high-speed main scanning is realized with high reliability.

According to a fourth aspect of the present invention, in the tomography apparatus according to the third aspect, the restricting means is formed with a bending portion, and the support member is slidable on the bending portion of the restricting means. The support member and the restricting means constitute the first rotating means and / or the second rotating means by being in contact with each other.

[Operation / Effect] According to the invention described in claim 4, the power transmitted from the rotating means by the regulating means formed with the curved portion and the support member slidably abutted on the curved portion. Thus, the detection surface of the detection means can be rotated. Therefore, it is not necessary to provide the first rotating means and / or the second rotating means as a separate drive source from the rotating means.

According to a fifth aspect of the present invention, in the tomography apparatus according to the fourth aspect of the present invention, the axis passing through the region of interest of the subject perpendicular to the tomographic axis is the second axis, and the tomographic axis and the second axis The support member and the restricting means are configured so that a linear motion component in the third axis direction of the holding rod is a rotational motion on an arc centering on the second axis of the support member itself with an orthogonal axis as a third axis. It is characterized by being converted into components.

[Operation / Effect] According to the fifth aspect of the present invention, the first rotating means (or the second axis as one in-plane axis) by the rotational motion component on the circular arc around the converted second axis (or , Second rotating means having the second axis as two in-plane axes).

According to a sixth aspect of the present invention, in the tomography apparatus according to any of the second to fifth aspects, the detection surface of the detection means is further orthogonal to the irradiation axis during main scanning. It is characterized by this.

[Operation / Effect] According to the invention described in claim 6, since the detection surface of the detection means is orthogonal to the irradiation axis, the reconstruction process can be suitably performed.

Further, the invention according to claim 7, in tomographic imaging apparatus according to any one of claims 1 to 6, wherein the illumination source when the main scanning, a non-rotating to the sectional axis parallel axes around It is characterized by being.

[Operation / Effect] According to the invention described in claim 7, during the main scanning, the irradiation source is not rotated around the axis parallel to the tomographic axis, and therefore moves in parallel around the tomographic axis. Thereby, in the main scanning, the relative positional relationship between the irradiation source and other static (fixed) objects does not twist. Therefore, main scanning can be performed in a state where the flexible cable is fixedly connected to the irradiation source.

The invention according to claim 8 is the tomography apparatus according to any one of claims 1 to 7 , further comprising a blade provided on the detection surface to remove scattering of electromagnetic waves. It is characterized by this.

[Operation / Effect] According to the invention described in claim 8, by providing the blade, scattering of electromagnetic waves can be removed.

According to a ninth aspect of the present invention, in the tomography apparatus according to the eighth aspect of the present invention, the blade has a shielding plate arranged so as to intersect in two axial directions.

[Operation / Effect] According to the invention described in claim 9, it is possible to suitably remove the scattering of electromagnetic waves.

The invention according to claim 10 is the tomography apparatus according to any one of claims 1 to 9 , wherein the irradiation source, the detecting means, and the tomographic axis are rotated around the second axis. The reconstructing process is further performed based on a group of projection data obtained from the detecting means at each time point of the sub-scanning. .

[Operation / Effect] According to the invention described in claim 10, a tomographic image of an isotropic spatial resolution of the subject can be obtained by sub-scanning the irradiation source and the detecting means.

  The present specification also discloses an invention relating to the following tomographic apparatus.

(1) In the tomography apparatus according to any one of claims 1 to 10, a transmission line for transmitting electric power or a signal, one end of which is fixedly connected to the detection means, and at least the detection means A tomography apparatus, wherein the other end of the transmission line is drawn out of the casing.

  According to the invention described in (1) above, the positional relationship between the detection means and the static housing in the main scanning is not twisted. Therefore, another device (for example, a power supply unit or an image processing unit) arranged outside the housing and the detection means inside the housing can be fixedly connected by the flexible cable. Therefore, electric power can be transmitted to the detection means without using a slip ring mechanism or the like. In addition, projection data obtained from the detection means can be transmitted without using the optical isolation method.

  According to the tomography apparatus of the present invention, the detection surface of the detection means is not rotated around an axis parallel to the tomographic axis during main scanning, and therefore moves in parallel around the tomographic axis. Thereby, in the main scanning, the relative positional relationship between the detection means and the other static (fixed) object is not twisted. Furthermore, since the detection surface of the detection means is orthogonal to the irradiation axis, the reconstruction process can be suitably performed.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of a tomography apparatus according to the first embodiment, FIG. 2 is a schematic vertical sectional view of the tomography apparatus, and FIG. 3 is a sectional view passing through a tomographic axis of a scanning frame. FIG. 4 is a perspective view inside the scanning frame.

  This tomography apparatus displays an imaging system 1 that obtains projection image data of a subject M, an image processing unit 2 that processes the obtained projection data to create a three-dimensional tomographic image, and the created tomographic image. The display device 3 is roughly divided.

  The imaging system 1 includes a top plate 4 on which a subject M is placed, a scanning frame 7 that houses a rotating anode X-ray tube 5 and a flat panel X-ray detector (hereinafter abbreviated as “FPD”) 6. And a base 8 for holding the scanning frame 7. The base 8 is fixedly installed on the floor surface.

  The tomographic axis B is an axis that passes through the region of interest P of the subject M, and is the main axis of main scanning described later. The body axis A is one of axes passing through the region of interest P of the subject M perpendicular to the tomographic axis B, and is a center axis of sub-scanning described later. The body axis A corresponds to the second axis in the present invention.

  The image processing unit 2 includes a detection signal collection unit 11, a main storage unit 13, a reconstruction processing unit 15, and a storage unit 17.

  Hereinafter, each part will be described.

  As shown in FIG. 2, a substantially semicircular frame holding member 9 for holding the scanning frame 7 is provided on the back side of the scanning frame 7, and a sub scanning belt is provided on the outer periphery of the frame holding member 9. 9a is attached. A groove is formed in the center of the base 8 so as to be curved, and a roller 10 that is rotated by a drive mechanism (not shown) is provided in the groove. The frame holding member 9 is slidably held on the inner peripheral surface of the groove of the base 8 in a state where the secondary scanning belt 9 a is hung on the roller 10. The frame holding member 9, the base 8, and the roller 10 correspond to the secondary scanning means in this invention. The scanning frame 7 corresponds to the housing in the present invention.

  As shown in FIGS. 3 and 4, in the scanning frame 7, in addition to the rotary anode X-ray tube 5 and the FPD 6, a rotary drive motor 31, a rotary drive shaft 32, an X-ray tube gear 33, and an X-ray It has a tube housing 34, an FPD gear 36, a rotary table 37, a holding frame 101, an FPD support member 103, and a flexible cable 111. It is desirable that the X-ray tube gear 33 and the FPD gear 36 have the same diameter.

  The rotation drive motor 31 is connected to the rotation drive shaft 32 through a gear. The rotation drive shaft 32 is connected to an X-ray tube casing 34 that is rotatable about the tomographic axis B via an X-ray tube gear 33. The rotary drive shaft 32 is connected to a rotary table 37 provided to be rotatable about the tomographic axis B via an FPD gear 36.

  In the X-ray tube casing 34, a rotating anode X-ray tube 5 is provided at a position eccentric from the tomographic axis B which is the center thereof.

  The rotary anode X-ray tube 5 employs a rotary anode X-ray tube type as its name suggests. That is, a cathode (filament) 41 that emits thermoelectrons, an anode (target) 42 that generates X-rays by accelerated collision of thermoelectrons emitted from the cathode 41, and the anode 42 are rotated at high speed around the center. A high-speed rotation shaft 43 to be moved, and a bearing portion 44 that rotatably supports the high-speed rotation shaft 43. The high-speed rotation shaft 43 is provided in parallel with the tomographic axis B. The rotating anode X-ray tube 5 corresponds to the irradiation source in the present invention.

  From the rotating anode X-ray tube 5, X-rays having a so-called “cone beam” shape opened by a predetermined angle are irradiated. This X-ray central trajectory, in other words, the trajectory connecting the irradiation source position Q (also referred to as the focal position of the X-ray tube) of the rotary anode X-ray tube 5 and the FPD 6 is referred to as an irradiation axis C. The rotary anode X-ray tube 5 is positioned so that the irradiation axis C passes through the region of interest P of the subject M.

  The rotary table 37 has a holding rod 37a at a position eccentric from the center thereof. The holding frame 101 is a frame body having four side surfaces, and a holding bar 37 a is inserted through an opening in the holding frame 101. The holding frame 101 includes two holding frame holding bars 101a that penetrate two opposing side surfaces and are parallel to the body axis A. These holding frame holding rods 101 a are fixedly installed on the scanning frame 7. Further, the holding frame 101 is provided with bearings at portions where the holding frame holding rod 101a penetrates, and is configured to be slidable only in the body axis A direction. Further, a guide groove 101b is formed on the inner walls of these two side surfaces along a concentric circle centering on the body axis A in a sectional view.

  FIG. 5 is a perspective view of a rotary linear bearing included in the FPD support member. As shown in FIG. 5, a rotary linear bearing 104 that is rotatable in two directions is provided at a substantially central portion of the FPD support member 103. The rotary linear bearing 104 has a through hole whose inner peripheral surface 104a is rotatable, and the through hole itself is configured to be rotatable about an axis g. The rotary linear bearing 104 is held by the rotary table 37 by being joined to the holding rod 37a.

  Further, two back plates 103a are provided on the back side of the FPD support member 103 so as to protrude. Each back plate 103a has a curved shape along a concentric circle with the body axis A as the center. Then, the rotary linear bearing 104 is slidably contacted with the guide groove 101b formed on the inner wall of the holding frame 101 in a state where the rotary linear bearing 104 is joined to the holding rod 37a.

  Further, the FPD support member 103 includes a stepping motor 105.

  6 is a perspective view of the FPD support member, and FIG. 7 is a plan view of the FPD support member. Please refer to FIG. The stepping motor 105 is installed on the front side of the FPD support member 103. The FPD 6 is supported so as to be capable of normal rotation and reverse rotation about an axis f that is an axis passing through the center of the detection surface within the detection surface. The stepping motor 105 is digitally controlled in synchronization with the movement of the FPD 6 so that the detection surface of the FPD 6 is always orthogonal to the irradiation axis C.

  More specifically, the stepping motor 105 is digitally controlled in accordance with the displacement of the FPD 6 in the body axis A direction with respect to the tomographic axis B. The axis f corresponds to one in-plane axis (or two in-plane axes) in the present invention.

  With the configuration described above, the position where the FPD 6 is supported is set so as to face the rotating anode X-ray tube 5 with the subject M interposed therebetween, as shown in FIG. Then, an irradiation axis C connecting the irradiation source position Q of the rotary anode X-ray tube 5 and the FPD 6 intersects the tomographic axis B at a predetermined angle θ in the region of interest P of the subject M and around the tomographic axis B. The rotating anode X-ray tube 5 and the FPD 6 move so as to rotate. In this specification, such movement of the rotary anode X-ray tube 5 and the FPD 6 is referred to as main scanning.

  Here, the angle θ formed by the irradiation axis C and the tomographic axis B is usually 45 degrees or less. Furthermore, a desirable angle θ is 15 degrees to 20 degrees.

  As shown in FIG. 7, the stepping motor 105 described above has an angle θf or an angle −θf, and the range of the angle θf is an angle between the irradiation axis C and the tomographic axis B, as shown in FIG. Below θ is sufficient.

  Further, the rotary table 37 is provided with a counterbalance 37b. The position of the counterbalance 37b is preferably a position facing the position where the holding rod 37a is disposed across the rotation center (tomographic axis B) of the rotary table 37, and is preferably on the peripheral side of the rotary table 37. The counter balance 37b is set so as to balance the moment applied to the holding rod 37a when the rotary table 37 rotates.

  The above-described rotation drive motor 31, rotation drive shaft 32, X-ray tube gear 33, X-ray tube housing 34, FPD gear 36, rotation table 37, holding frame 101, and FPD support member 103 are the main scanning in the present invention. Corresponds to means. The rotary table 37, the holding frame 101, and the FPD support member 103 correspond to the rotation means, the regulation means, and the support member in the present invention, respectively. The holding frame 101 and the FPD support member 103 constitute first rotating means (or second rotating means) in the present invention. The stepping motor 105 corresponds to the second rotating means (or first rotating means) in the present invention.

  The configuration of the FPD 6 will be described with reference to FIGS. FIG. 8 is a vertical sectional view of a main part of the FPD, and FIG. 9 is a plan view of the FPD.

  The FPD 6 includes an application electrode 51, an X-ray sensitive semiconductor film 53, a carrier collection electrode 55, and an active matrix substrate 57, which are sequentially stacked from the X-ray incident side. That is, the FPD 6 is a direct conversion type that directly converts X-rays into electric charges.

  The semiconductor film 53 is exemplified by amorphous selenium or the like. The active matrix substrate 57 is exemplified by a glass substrate having electrical insulation.

  The carrier collecting electrodes 55 are separately formed in a two-dimensional matrix in plan view. On the active matrix substrate 57, for each carrier collecting electrode 55, there are a capacitor Ca for storing charge information, and a switch element for connecting the carrier collecting electrode 55 and the capacitor Ca to the source S to take out charge information. Thin film transistors Tr are formed separately.

  One detection element d is constituted by the one set of carrier collection electrode 55, capacitor Ca, and thin film transistor Tr.

  Furthermore, on the active matrix substrate 57, a gate bus line 61 is laid for each row of the detection elements d, and a data bus line 63 is laid for each column of the detection elements d. Each gate bus line 61 is commonly connected to the gates of the thin film transistors Tr in each row. Each data bus line 63 is commonly connected to the drains of the thin film transistors Tr in each column.

  Further, the FPD 6 has a plurality of amplifiers 65 on one end side of the active matrix substrate 57. A gate driver 69 is provided on the other end side of the active matrix substrate 57.

  A data bus line 63 is connected to each amplifier 65. Each gate bus line 61 is connected to the gate driver 69. In addition, an A / D converter (not shown) is provided on the output side of the amplifier 65. The FPD 6 corresponds to the detecting means in this invention.

  The operation in the FPD 6 will be described. When X-rays enter the FPD 6 with a bias voltage applied to the application electrode 51, charges are generated in the semiconductor film 53, and the charges are accumulated in the capacitor Ca through the carrier collection electrodes 55. The gate bus line 61 transmits a scanning signal from the gate driver 69 and applies it to the gate of the thin film transistor Tr. As a result, the charge information stored in the capacitor Ca is read out to the data bus line 63 via the thin film transistor Tr that has been turned on. The charge information read through each data bus line 63 is amplified by an amplifier 65. Thereafter, it is digitized by an A / D converter to obtain a detection signal.

  There are a plurality of flexible cables 111. Each flexible cable 111 is selectively used in accordance with an application for supplying electric power or an application for transmitting a detection signal. The flexible cable corresponds to the transmission line in the present invention.

  Each flexible cable 111 is fixedly connected to the back side of the FPD 6. Here, “fixed” means not connected by rolling contact. Then, an extra length is provided to the extent that the movement of the FPD 6 is not hindered, and the opening of the scanning frame 7 is laid along a predetermined path that is not buffered by the FPD support member 103, the rotation drive shaft 32, or the like. Each flexible cable 111 is drawn out of the scanning frame 7 through this opening, and is connected to a power supply (not shown) or the image processing unit 2.

  Next, the image processing unit 2 will be described.

  The detection signal collecting unit 11 collects detection signals from the FPD 6. The main storage unit 13 stores detection signals.

  The reconstruction processing unit 15 performs a reconstruction process based on the detection signal stored in the main storage unit 13 and creates a tomographic image.

  The storage unit 17 stores the tomographic image obtained from the reconstruction processing unit 15. Then, a tomographic image is displayed on the display device 3 in accordance with the operator's instructions as appropriate.

  The image processing unit 2 is realized by a central processing unit (CPU) that reads and executes a predetermined program, a RAM (Random-Access Memory) that stores various types of information, a storage medium such as a fixed disk, and the like.

  Next, the operation of the tomography apparatus according to the first embodiment will be described separately for the imaging system 1, the image processing unit 2, and the display device 3.

<Imaging system 1>
In the imaging system 1, the roller 10 provided on the base 8 is rotationally driven by a drive mechanism (not shown) to send the sub-scanning belt 9 a. As a result, the frame holding member 9 and the scanning frame 7 are reciprocally rotated around the body axis A together. Thereby, the rotary anode X-ray tube 5 and the FPD 6 in the scanning frame 7 can be moved so as to rotate the tomographic axis B around the body axis A. Such movement of the rotary anode X-ray tube 5 and the FPD 6 is called secondary scanning.

  In this embodiment, the tomographic axis B is configured to be rotatable about 180 ° around the body axis A.

  In the scanning frame 7, the rotation drive motor 31 rotates the rotation drive shaft 32. The rotation drive shaft 32 rotates the X-ray tube casing 34 via the X-ray tube gear 33 and rotates the rotary table 37 via the FPD gear 36.

  As the X-ray tube casing 34 rotates, the rotary anode X-ray tube 5 accommodated therein rotates about the tomographic axis B. Furthermore, the anode 42 of the rotary anode X-ray tube 5 rotates about the high-speed rotation shaft 43 by the rotation of the high-speed rotation shaft 43 itself.

  On the other hand, the rotation of the rotary table 37 causes the FPD support member 103 to move on a circular orbit whose radius is the distance that the holding rod 37a is eccentric with respect to the tomographic axis B. At this time, when the back plate 103a of the FPD support member 103 abuts against the inner wall of the holding frame 101, the FPD support member 103 itself does not rotate about the rotary linear bearing 104 (the axis of the holding rod 37a). Be regulated. Further, the back plate 103a of the FPD support member 103 slides along the guide groove 101b of the holding frame 101 in accordance with the rotational movement of the holding rod 37a. As a result, the FPD support member 103 reciprocates along a concentric arc centered on the body axis A.

  That is, the movement of the FPD support member 103 is a combination of the linear motion component m1 in the body axis A direction and the arc-shaped rotational motion component m3 centered on the body axis A. The movement of the holding rod 37a is considered to be a combination of the linear motion component m1 in the body axis A direction and the linear motion component m2 in the third axis D direction, which is an axis orthogonal to the body axis A and the tomographic axis B. Can do. That is, the FPD support member 103 and the holding frame 101 convert the linear motion component m2 of the holding rod 37a in the third axis D direction into an arc-shaped rotational motion component m3 centered on the body axis A of the FPD support member 103 itself. Will be converted.

  Further, the stepping motor 105 rotates the FPD 6 in accordance with the displacement of the FPD support member 103 in the body axis A direction (linear motion component m1 in the body axis A direction). Thereby, the linear motion component m1 of the FPD support member 103 in the body axis A direction is converted into the linear motion component m1 of the FPD 6 in the body axis A direction and the rotational motion about the axis f of the FPD 6.

  The rotational motion component m3 of the FPD support member 103 becomes an arc-shaped rotational motion component m3 centered on the body axis A of the FPD 6 as it is.

  As described above, the FPD 6 includes the linear motion component m1 in the direction of the body axis A of the FPD 6, the arc-shaped rotational motion component m3 about the body axis A of the FPD 6, and the rotational motion component about the axis f of the FPD 6. It will be synthesized. The rotational motion component m3 includes a rotational motion component of the FPD 6 centering on an axis in the detection surface of the FPD 6 orthogonal to the axis f and passing through the center of the detection surface. This axis corresponds to two in-plane axes (or one in-plane axis) in the present invention.

  Further, the detection surface of the FPD 6 does not rotate at all around an axis parallel to the tomographic axis B. Therefore, each flexible cable 111 connected to the FPD 6 does not twist. Note that the displacement amount of the FPD 6 is absorbed by the extra length of each flexible cable 111.

  The FPD 6 is viewed from another point of view as follows. FIG. 10 is a schematic diagram illustrating a positional relationship between the rotary anode X-ray tube and the FPD in the main scanning according to the first embodiment. As shown in FIG. 10, the FPD 6 moves along a curve TF1 (also referred to as a saddle shape) that connects the intersection of a virtual cylinder Ac centered on the body axis A and a virtual cylinder Bc centered on the tomographic axis B. . Note that the detection surface of the FPD 6 is always inclined so as to be orthogonal to the irradiation axis C.

  Even during the secondary scanning, the FPD 6 and the rotary anode X-ray tube 5 are moved so that the tomographic axis B is rotated around the body axis A. Therefore, the relative positional relationship between the FPD 6 and the rotary anode X-ray tube 5 Is the same as in the case of main scanning. Therefore, the detection surface of the FPD 6 is always orthogonal to the irradiation axis C even during the secondary scanning.

  A detection signal obtained from the FPD 6 is given to the image processing unit 2 through the flexible cable 111 at each time point of the main scanning and the sub scanning of the imaging system 1.

<Image Processing Unit 2 and Display Device 3>
The detection signal collecting unit 11 collects detection signals obtained from the FPD 6 at each time point of the main scanning and the sub scanning. The reconstruction processing unit 15 performs reconstruction processing based on the collected detection signals and generates a tomographic image. The storage unit 17 stores the tomographic image generated by the reconstruction processing unit 15. The display device 3 displays the tomographic image stored in the storage unit 17.

  Here, the operation of the reconstruction processing unit 15 will be described in detail with reference to FIGS. 11 and 12. FIG. 11 is a schematic diagram for explaining the procedure of reconstruction processing based on main scanning, and FIG. 12 is a schematic diagram for explaining the procedure of reconstruction processing based on main scanning and sub scanning.

  First, a simple back projection (simple back projection: simple BP) is performed on the group of photographing data to generate a simple BP intermediate image. Next, this simple BP intermediate image is subjected to three-dimensional Fourier transform, and is converted into a three-dimensional Fourier distribution image converted from real space data to Fourier space data (FIGS. 11 and 12 are displayed in three-dimensional Fourier space coordinates. Corresponding to the one). Next, filtering processing is performed on the three-dimensional Fourier distribution image (| ω | filtering (absolute value omega filtering) or low-pass filtering). Next, the filtered three-dimensional Fourier distribution image is subjected to three-dimensional inverse Fourier transform to return from the Fourier space data to the real space data, and is displayed on the right end side in the three-dimensional volume data (FIGS. 11 and 12). , Corresponding to a cylindrical shape in which several broken lines are illustrated in the circumferential direction). In this way, image reconstruction for generating three-dimensional volume data of the region of interest P is performed. By selecting an image of an arbitrary tomographic plane from this three-dimensional volume data, the selected tomographic image can be seen (FIGS. 11 and 12 show a thin cylindrical shape displayed at the rightmost end. Corresponding to what you are seeing). As described above, a method of once generating a simple BP intermediate image and subjecting the simple BP intermediate image to a predetermined filtering process in Fourier space is called an F (Fourier) spatial filter method.

  When the reconstruction process is performed based on the main scanning and the sub-scanning (corresponding to the procedure shown in FIG. 12), the resolution in the tomographic axis B direction can be increased, and the isotropic spatial resolution tomography of the subject. An image can be obtained.

  As described above, according to the tomographic imaging apparatus according to the first embodiment, the detection surface of the FPD 6 does not rotate at all around the axis parallel to the tomographic axis B at each time point of the main scanning and the secondary scanning. The flexible cables 111 connected to the FPD 6 are not twisted. Therefore, since power can be transmitted to the FPD 6 only by the flexible cable 111, a slip ring mechanism is not required. Further, since the detection signal from the FPD 6 to the image processing unit 2 can be transmitted only by the flexible cable 111, an optical transmitter and an optical receiver necessary for the optical isolation method are not required.

  Further, when the secondary scanning is performed, the base 8 can be made compact by rotating while holding a part of the frame holding member 9, and the floor occupation area of the entire tomography apparatus can be reduced. Can be reduced. Further, opening the upper part of the subject M gives the subject M a feeling of opening.

  Further, since the high-speed rotation shaft 43 of the rotary anode X-ray tube 5 is always parallel to the tomographic axis B during main scanning, the force applied to the bearing unit 44 during rotation around the tomographic axis B is reduced, and the bearing unit 44 can be prevented from being damaged.

  Further, by installing the counter balance 37b on the rotary table 37, it is possible to prevent inconveniences such as the vibration of the rotary table 37 during rotation.

  In addition, the X-ray tube gear 33 and the FPD gear 36 have the same diameter, and the X-ray tube gear 33 and the FPD gear 36 are connected to the rotary drive shaft 32, whereby the rotary anode X-ray tube 5 and the FPD 6 are connected. And can be easily synchronized with each other.

  Embodiment 2 of the present invention will be described below with reference to the drawings. In addition, about the same structure as Example 1, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol. FIG. 13 is a block diagram illustrating a schematic configuration of the tomography apparatus according to the second embodiment, FIG. 14 is a cross-sectional view passing through the tomographic axis of the scanning frame, and FIG. 15 is a perspective view inside the scanning frame. FIG. 16 is a perspective view of the FPD support member.

  The image processing unit 2 includes a detection signal collection unit 11, a main storage unit 13, a blade stripe removal unit 14, a reconstruction processing unit 15, and a storage unit 17.

  Hereinafter, each part will be described.

  As shown in FIGS. 14 and 15, in the scanning frame 7, in addition to the rotary anode X-ray tube 71 and the FPD 6, an X-ray tube rotation drive motor 80X, an X-ray tube gear 33, and an X-ray tube rotary table are provided. 81, an X-ray tube holding frame 82, an X-ray tube support member 83, an FPD rotation drive motor 80F, an FPD gear 36, a rotary table 37, a holding frame 121, and an FPD support member 123. Further, a blade 141 is provided on the detection surface of the FPD 6.

  In the second embodiment, rotation drive motors 80X and 80F are separately provided for the X-ray tube and the FPD. These X-ray tube and FPD rotary drive motors 80X and 80F are digitally controlled to rotate synchronously by a control unit (not shown).

  The X-ray tube rotation drive motor 80 </ b> X is connected to an X-ray tube rotation table 81 provided to be rotatable about the tomographic axis B via an X-ray tube gear 33. Further, the FPD rotation drive motor 80F is connected to a rotation table 37 provided to be rotatable about the tomographic axis B via the FPD gear 36.

  The X-ray tube rotary table 81 has a holding rod 81a at a position eccentric from the center thereof. The X-ray tube holding frame 82 is a frame body having four side surfaces, and a holding rod 81 a is inserted through an opening in the X-ray tube holding frame 82. The X-ray tube holding frame 82 includes two holding frame holding bars 82a that pass through two opposing side surfaces and are parallel to the body axis A. These holding frame holding bars 82 a are fixedly installed on the scanning frame 7. Further, the X-ray tube holding frame 82 is provided with bearings at portions where the holding frame holding rod 82a penetrates, and is configured to be slidable only in the body axis A direction.

  The X-ray tube support member 83 has a bearing 83a having a hole whose inner peripheral surface is rotatable, and the bearing 83a is held by the rotary table 81 for the X-ray tube by joining to the holding rod 81a. Further, a back plate 83b that contacts the inside of the X-ray tube holding frame 82 is provided on the back side of the X-ray tube support member 83 so that the direction of the X-ray tube support member 83 is always in a fixed direction. Has been. Further, the X-ray tube support member 83 is arranged so that the X-ray tube generated by the rotary anode X-ray tube 71 irradiates the region of interest P of the subject M when the X-ray tube rotary table 81 rotates. The wire tube 71 is supported at a predetermined position.

  The rotary anode X-ray tube 71 includes a cathode (filament) 75 that emits thermoelectrons, an anode (target) 76 that generates X-rays by accelerated collision of thermoelectrons emitted from the cathode 75, and the anode 76 as its anode 76. A high-speed rotation shaft 77 that rotates around the center and a bearing portion (not shown) that rotatably supports the high-speed rotation shaft 77 are provided. The rotary anode X-ray tube 71 corresponds to the irradiation source in the present invention.

  In the rotary anode X-ray tube 71, the relative positions of the cathode 75 and the anode 76 are different from those of the rotary anode X-ray tube 5 of the first embodiment. The high-speed rotation shaft 77 of the rotary anode X-ray tube 71 is provided so as to be orthogonal to the tomographic axis B.

  The rotary table 37 has a holding rod 37a at a position eccentric from the center thereof. The holding frame 121 is a frame body having four side surfaces, and a holding rod 37 a is inserted through an opening in the holding frame 121. The holding frame 121 includes two holding frame holding rods 121a that pass through two opposing side surfaces and are parallel to the body axis A. These holding frame holding rods 121 a are fixedly installed on the scanning frame 7. Further, the holding frame 121 is provided with a bearing at each part through which the holding frame holding rod 121a penetrates, and is configured to be slidable only in the body axis A direction. Further, linear guide grooves 121b are formed on the inner walls of these two side surfaces.

  The FPD support member 123 has a bearing 123a having a hole whose inner peripheral surface can freely rotate, and the bearing 123a is held by the rotary table 37 by joining to the holding rod 37a. Further, two back plates 123b are provided on the back side of the FPD support member 123 so as to protrude. The bearing 123a is slidably contacted with the guide groove 121b formed on the inner wall of the holding frame 121 in a state where the bearing 123a is joined to the holding rod 37a. Accordingly, the FPD support member 123 itself is configured to be restricted from rotating around the bearing 123a.

  Refer to FIG. FIG. 16 is a perspective view of the FPD support member according to the second embodiment. The FPD support member 123 includes a first stepping motor 124, a rotating frame 126 that is rotatably supported by the first stepping motor 124, and a second stepping motor 129 that is provided integrally with the rotating frame 126. The second stepping motor 129 supports the FPD 5 so as to be rotatable.

  The first stepping motor 124 is disposed on the FPD support member 123 so as to rotate the rotating frame 126 around an axis f2 parallel to the body axis A. The second stepping motor 129 is provided integrally with the rotating frame 126 so as to rotate the FPD 6 around an axis f1 orthogonal to the axis f2 whose intersection passes through the center of the detection surface. These stepping motors 124 and 129 are digitally controlled in synchronization with the movement of the FPD 6 so that the detection surface of the FPD 6 is always orthogonal to the irradiation axis C.

  More specifically, the first stepping motor 124 is digitally controlled according to the displacement amount of the FPD 6 in the third axis D direction with respect to the tomographic axis B. At this time, the shaft f1 also rotates. Further, the second stepping motor 129 is digitally controlled in accordance with the amount of displacement of the FPD 6 in the body axis A direction with respect to the tomographic axis B. By this operation, the FPD 6 rotates around the axis f2 and the axis f1. Note that the axis f1 and the axis f2 correspond to one in-plane axis and two in-plane axes in the present invention.

  Refer to FIG. FIG. 17 is a schematic diagram showing the relationship between the position of the FPD and the rotation angles around the axes f1 and f2. When the rotary table 37 rotates at a rotational angular velocity ω (constant) and a period T, the rotational angles θf1 and θf2 of the shaft f1 and the shaft f2 have a maximum amplitude as shown in FIG. It is an angle θ formed with B, and the characteristics are 90 degrees out of phase with each other.

    With the configuration described above, the position where the FPD 6 is supported is set so as to face the rotating anode X-ray tube 71 with the subject M interposed therebetween, as shown in FIG. Then, the irradiation axis C connecting the irradiation source position Q of the rotary anode X-ray tube 71 and the FPD 6 intersects the tomographic axis B at a predetermined angle θ in the region of interest P of the subject M and around the tomographic axis B. Main scanning is performed to move the rotary anode X-ray tube 71 and the FPD 6 so as to rotate.

  The X-ray tube rotation drive motor 80X, the FPD rotation drive motor 80F, the X-ray tube gear 33, the X-ray tube rotation table 81, the X-ray tube support member 83, the FPD gear 36, the rotation table 37, the holding frame 121 and The FPD support member 123 corresponds to the main scanning means in this invention. Further, the rotary table 37, the holding frame 121, and the FPD support member 123 correspond to the rotation means, the regulation means, and the support member in the present invention, respectively. The first and second stepping motors 124 and 129 correspond to the first rotating means and the second rotating means in the present invention, respectively.

  Please refer to FIG. FIG. 18 is a perspective view of a blade provided on the detection surface of the FPD. A blade 141 for removing scattered X-rays is provided on the detection surface of the FPD 6. The blade 141 is provided with a plurality of shielding plates arranged so as to intersect with each other in two axial directions so as to be inclined toward the irradiation source position Q of the rotary anode X-ray tube 71. Examples of the material of the shielding plate include molybdenum and tungsten. The blade 141 corresponds to the blade in the present invention.

  As for the image processing unit 2, only the blade stripe removal unit 14 will be described.

  The blade stripe removal unit 14 removes the shadow of each shielding plate of the blade 141 (hereinafter referred to as “blade stripe component”) from the detection signal stored in the main storage unit 13.

  The blade stripe removal unit 14 is also realized by a central processing unit (CPU) that reads and executes a predetermined program, a RAM (Random-Access Memory) that stores various information, a storage medium such as a fixed disk, and the like. .

  Next, the operation of the tomography apparatus according to the second embodiment will be described separately for the imaging system 1, the image processing unit 2, and the display device 3.

<Imaging system 1>
In the imaging system 1, since the secondary scanning is the same as that in the first embodiment, the main scanning will be described.

  In the scanning frame 7, the X-ray tube and FPD rotary drive motors 80 </ b> X and 80 </ b> F are driven under synchronous control by a control unit (not shown). The X-ray tube rotation drive motor 80 </ b> X rotates the X-ray tube table 81 via the X-ray tube gear 33. The FPD rotation drive motor 80 </ b> F rotates the rotary table 37 via the FPD gear 36.

  By the rotation of the X-ray tube table 81, the X-ray tube support member 83 moves on a circular orbit whose radius is the distance that the holding rod 81a is eccentric from the tomographic axis B. At this time, the back plate 83b of the X-ray tube support member 83 is in contact with the X-ray tube holding frame 82, so that the direction of the X-ray tube support member 83 is always regulated to be in a certain direction. Therefore, the X-ray tube support member 83 moves in parallel along the circular orbit.

  The rotary anode X-ray tube 71 moves around the tomographic axis B together with the X-ray tube support member 83. Therefore, the rotary anode X-ray tube 71 also moves in parallel on the circular orbit without changing its posture. Further, the anode 76 of the rotary anode X-ray tube 71 rotates around its center by the rotation of the high-speed rotation shaft 77 itself.

  On the other hand, the rotation of the rotary table 37 causes the FPD support member 123 to move on a circular orbit whose radius is the distance that the holding rod 37a is eccentric with respect to the tomographic axis B. At this time, when the back plate 123b of the FPD support member 123 contacts the holding frame 121, the direction of the FPD support member 123 is always regulated to be in a certain direction. Therefore, the FPD support member 123 moves in parallel along the circular orbit.

  The first stepping motor 124 provided on the FPD support member 123 rotates the FPD 6 according to the displacement amount of the FPD support member 123 in the third axis D direction (linear motion component m2 in the third axis D direction). The second stepping motor 129 rotates the FPD 6 in accordance with the amount of displacement of the FPD support member 123 in the body axis A direction (linear motion component m1 in the body axis A direction).

  As a result, the linear motion component m2 in the third axis D direction of the FPD support member 123 is converted into a linear motion component m2 in the body axis D direction of the FPD 6 and a rotational motion about the axis f2. Similarly, the linear motion component m1 of the FPD support member 123 in the body axis A direction is converted into a linear motion component m1 of the FPD 6 in the body axis A direction and a rotational motion about the axis f1.

  Note that the detection surface of the FPD 6 does not rotate at all around an axis parallel to the tomographic axis B. Therefore, each flexible cable 111 connected to the FPD 6 is not twisted. Note that the displacement amount of the FPD 6 is absorbed by the extra length of each flexible cable 111.

  The FPD 6 is viewed from another point of view as follows. FIG. 19 is a schematic diagram showing the positional relationship between the rotary anode X-ray tube and the FPD in main scanning. As shown in FIG. 19, the rotary anode X-ray tube 71 rotates on a circular orbit TX around the tomographic axis B, and the FPD 6 moves on a circular orbit TF2 around the tomographic axis B. At this time, the detection surface of the FPD 6 is always inclined so as to be orthogonal to the irradiation axis C.

  In FIG. 19, one side portion of the detection surface is schematically illustrated by a double line on the FPD 6 in order to clearly show that the FPD 6 moves in parallel on the circular orbit TF2.

  A detection signal obtained from the FPD 6 is given to the image processing unit 2 through the flexible cable 111 at each time point of the main scanning and the sub scanning of the imaging system 1.

  The blade 141 moves together with the FPD 6. For this reason, the blade 141 always faces each irradiation plate to the irradiation source position Q of the rotary anode X-ray tube 71 during main scanning.

  In the secondary scan, the FPD 6 and the X-ray tube 71 are moved so that the tomographic axis B is rotated around the body axis A. Therefore, the relative positional relationship between the FPD 6 and the X-ray tube 71 is the same as that of the main scan. Same as the case. Therefore, also in the secondary scanning, the detection surface of the FPD 6 is always orthogonal to the irradiation axis C, and each shielding plate of the blade is directed to the irradiation source position Q.

  The detection signal obtained from the FPD 6 is given to the image processing unit 2 at each time point of the main scanning and the sub scanning of the imaging system 1.

<Image Processing Unit 2 and Display Device 3>
Since the operations of the reconstruction processing unit 15 and the like are the same as those in the first embodiment, the operation of the blade stripe removal unit 14 will be described.

  The fringe component of the blade 141 is extracted from the detection signal for one frame by FIR (Finite Impulse Response) filtering or the like. The extracted stripe component portion of the blade 141 is repaired by the surrounding detection signal. As specific extraction of the fringe component of the blade 141, two-dimensional Fourier transform and the like are exemplified.

  As described above, even in the tomographic imaging apparatus according to the second embodiment, at each time point of the main scanning and the sub-scanning, there is no rotational movement around the axis parallel to the tomographic axis B that penetrates the center of the FPD 6. The flexible cables 111 connected to the FPD 6 are not twisted. Therefore, since power can be transmitted to the FPD 6 only by the flexible cable 111, a slip ring mechanism is not required. Further, since the detection signal from the FPD 6 to the image processing unit 2 can be transmitted only by the flexible cable 111, an optical transmitter and an optical receiver necessary for the optical isolation method are not required.

  Further, since the high-speed rotation shaft 77 of the rotary anode X-ray tube 71 faces the same direction during main scanning, the force applied to the bearing portion (not shown) is reduced and the bearing portion is prevented from being damaged. be able to. Incidentally, compared to the case where the X-ray tube is fixedly provided on the X-ray tube table 81 and the high-speed rotary shaft 77 rotates integrally with the rotary table 81, an effect of reducing the force applied to the bearing portion can be obtained. The non-rotation similar to that on the FPD 6 side eliminates the need for a slip ring mechanism for supplying a high voltage to the X-ray tube 81 and simplifies wiring similar to that on the FPD 6 side.

  In addition, since the detection surface of the FPD 6 is always orthogonal to the irradiation axis C, each shielding plate is connected to the rotating anode X even if the blade 141 is provided with a plurality of shielding plates arranged so as to intersect the two axes. It can face the irradiation source position Q of the ray tube 71. Therefore, X-ray scattered rays can be suitably removed, and X-rays are not shielded more than necessary by each shielding plate.

  Further, the rotation drive shaft 32 can be omitted by providing the rotation drive motors 80X and 80F separately for the X-ray tube and the FPD. Thereby, the freedom degree of the shape of the scanning frame 7 spreads.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In each of the above-described embodiments, the detection surface of the FPD 6 is inclined so as to be orthogonal to the irradiation axis C during main scanning, but is not limited thereto. For example, it may be configured not to rotate around an axis (for example, axis f, axis f1, axis f2, etc.) in the detection surface during main scanning. In this case, in Example 1, the guide groove 101b of the holding frame 101 and the back plate 103a of the FPD support member 103 do not need to be curved, and may be linear. Further, the stepping motor 105 can be omitted. Similarly, in the second embodiment, the first and second stepping motors 124 and 129 can be omitted.

  (2) When the detection surface of the FPD 6 is orthogonal to the irradiation axis C during main scanning, the first embodiment includes the stepping motor 105 and rotates the detection surface of the FPD 6 around the axis f. In No. 2, the first and second stepping motors 124 and 129 are rotated about the axis f1 and the axis f2, respectively. However, with the configuration of the holding frame 101 and the FPD support member 103, the detection surface of the FPD 6 may be rotated only by the rotation of the rotary table 37, so that only one stepping motor is omitted. Thus, in the first embodiment, the stepping motor 105 is omitted, and only the rotational drive motor 31 is sufficient. In the second embodiment, the same arcuate slide as that of m3 in FIG. 4 is used in two axes, so that the first and second stepping motors 124 and 129 are omitted, and only the FPD rotary drive motor 80F is sufficient.

  (3) In the above-described second embodiment, the blade 141 includes the shielding plate that intersects the two axial directions, but is not limited thereto. For example, a blade including a shielding plate arranged only in one axial direction may be used.

  (4) In each embodiment described above, the shape of the FPD 6 is not limited to a flat plate. For example, the detection surface may have a curved shape.

  (5) In each of the embodiments described above, the FPD 6 has been described as an example, but the present invention can be applied to any X-ray detector having a plurality of detection elements d on the detection surface.

  In the above-described embodiment, the FPD 6 has been described by taking a direct conversion type detector as an example, but is not limited thereto. For example, an indirect detection element that converts incident X-rays into light with a scintillator and converts the light into charge information with a semiconductor layer formed of a photosensitive material may be used.

  (6) In the above-described embodiment, the FPD 6 is a detector that detects the incidence of X-rays, but what is incident is not limited to X-rays. The present invention can also be applied to cases in which radiation other than X-rays, electromagnetic waves, and light are incident.

  (7) In each of the above-described embodiments, the medical X-ray imaging apparatus is used. However, the present invention is not limited to this. For example, the present invention can also be applied to a radiation imaging apparatus used in industrial fields such as non-destructive inspection, RI (Radio Isotope) inspection, and optical inspection, and in the nuclear power field. In each embodiment, the subject M is described, but the subject M is not limited to the human body.

  (8) In each example, the body axis A of the subject M has been described. However, it is not particularly limited by the term “body axis”, and the subject's interest is perpendicular to the tomographic axis. If it is one axis passing through the part, it is changed as appropriate.

1 is a block diagram illustrating a schematic configuration of a tomography apparatus according to Embodiment 1. FIG. It is a schematic vertical sectional view of a tomography apparatus. It is sectional drawing which passes along the tomographic axis of a scanning frame. It is a perspective view in a scanning frame. It is a perspective view of the rotation type linear bearing which an FPD support member has. It is a perspective view of a FPD support member. It is a top view of a FPD support member. It is a vertical sectional view of the principal part of FPD. It is a top view of FPD. It is a schematic diagram which shows the positional relationship of the rotating anode X-ray tube and FPD in main scanning. It is a schematic diagram for demonstrating the procedure of the reconstruction process based on main scanning. It is a schematic diagram for demonstrating the procedure of the reconstruction process based on main scanning and subscanning. 5 is a block diagram illustrating a schematic configuration of a tomography apparatus according to Embodiment 2. FIG. It is sectional drawing which passes along the tomographic axis of a scanning frame. It is a perspective view in a scanning frame. It is a perspective view of a FPD support member. It is a schematic diagram which shows the relationship between the position of FPD, and the rotation angle around the axis | shaft f1 and the axis | shaft f2. It is a perspective view of the braid | blade provided in the detection surface of FPD. It is a schematic diagram which shows the positional relationship of the rotating anode X-ray tube and FPD in main scanning. It is a schematic wiring diagram of the conventional radiation imaging device.

Explanation of symbols

5, 71 ... Rotating anode X-ray tube 6 ... Flat panel X-ray detector (FPD)
DESCRIPTION OF SYMBOLS 7 ... Scanning frame 8 ... Base 9 ... Frame holding member 10 ... Roller 15 ... Reconstruction processing part 31 ... Rotary drive motor 34 ... X-ray tube housing 37 ... Rotary table 101, 121 ... Holding frame 103, 123 ... FPD support Member 105, 124, 129 ... Stepping motor 111 ... Flexible cable 141 ... Blade d ... Detecting element A ... Body axis B ... Stomach axis C ... Irradiation axis D ... Third axis m1 ... Linear motion component in body axis direction m2 ... No. Linear motion component in three axial directions m3 ... Rotational motion component on an arc centered on the body axis Ac ... A virtual cylinder centered on the body axis Bc ... A virtual cylinder centered on the fault axis P ... Part of interest f, f1, f2 …axis

Claims (10)

An irradiation source that irradiates the subject with electromagnetic waves, a detection unit that is disposed opposite to the irradiation source with the subject interposed therebetween, and obtains projection data of the subject from electromagnetic waves that have passed through the subject, the irradiation source, and the detection The irradiation source and the detection means are moved around the tomographic axis so that the irradiation axis connecting the means is rotated around the tomographic axis while being inclined at a predetermined angle with respect to the tomographic axis passing through the region of interest of the subject. A tomography apparatus for acquiring a three-dimensional tomographic image by performing reconstruction processing based on a group of projection data obtained from the detection means at each time point of main scanning, The detection surface of the detection means is non-rotated around an axis parallel to the tomographic axis during main scanning ,
1st rotation means which rotates the said detection surface centering on 1 axis | shaft in an in-plane surface with the axis | shaft in the said detection surface passing through the center of the said detection surface as 1 axis | shaft in the surface, The said 1st rotation means is the said detection A tomography apparatus, wherein the detection surface is rotated in accordance with a displacement amount of the means from a tomographic axis . 2. The tomography apparatus according to claim 1 , further comprising: an axis within the detection plane that is orthogonal to an in-plane axis at the center of the detection plane, wherein the axis within the detection plane is two in-plane axes, and the detection is performed with respect to two in-plane axes. A tomography apparatus comprising: a second rotation unit configured to rotate a surface, wherein the second rotation unit rotates the detection surface according to a displacement amount of the detection unit from a tomographic axis. The tomography apparatus according to claim 2 , wherein the main scanning unit is joined to the holding rod via a bearing and a rotating unit that rotates the holding rod along a predetermined circular orbit around the tomographic axis, and the detection is performed. A tomography apparatus comprising: a support member that supports the means; and a restriction means that restricts rotation of the support member around the bearing. 4. The tomography apparatus according to claim 3 , wherein the restricting means is formed with a curved portion, and the support member is slidably contacted with the curved portion of the restricting means, so that the support member and the The tomographic apparatus is characterized in that the restricting means constitutes the first rotating means and / or the second rotating means. 5. The tomography apparatus according to claim 4, wherein an axis passing through a region of interest of the subject perpendicular to the tomographic axis is a second axis, and an axis orthogonal to the tomographic axis and the second axis is a third axis. The member and the regulating means convert a linear motion component in the third axis direction of the holding rod into a rotational motion component on an arc centered on the second axis of the support member itself. apparatus. The tomography apparatus according to any one of claims 2 to 5 , wherein the detection surface of the detection means is further orthogonal to the irradiation axis during main scanning. The tomography apparatus according to claim 1 , wherein the irradiation source is non-rotated around an axis parallel to the tomographic axis during main scanning. The tomography apparatus according to claim 1 , further comprising a blade provided on the detection surface to remove scattering of electromagnetic waves. 9. The tomography apparatus according to claim 8 , wherein the blade has a shielding plate arranged so as to intersect in two axial directions. 10. The tomographic apparatus according to claim 1 , further comprising: a slave scanning unit that performs slave scanning to move the irradiation source and the detection unit so that the tomographic axis is rotated around the second axis. The tomography apparatus is further characterized in that the reconstruction processing is further performed based on a group of projection data obtained from the detection means at each time point of sub-scanning.

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