JP2023147381A - X-ray ct apparatus - Google Patents

Abstract

To effectively cool a device in a unit while suppressing noise of the unit by the rotation of a rotation part.SOLUTION: An X-ray CT device includes an X-ray irradiation part, a plurality of units, a rotation part, and a projection part. The X-ray irradiation part emits an X-ray. Each of the plurality of units is provided with a suction port, an exhaust port, and a fan that sucks air from the suction port and discharges air from the exhaust port. The rotation part rotatably holds the X-ray irradiation part and the plurality of units. The projection part is provided on the upstream side of the air flow generated in the outside of at least one of the units by the rotation of the rotation part of the exhaust port of at least one of the plurality of units.SELECTED DRAWING: Figure 2

Description

The embodiments disclosed in this specification and the drawings relate to an X-ray CT (Computed Tomography) device.

2. Description of the Related Art There are medical image diagnostic apparatuses that generate medical image data in which internal tissues of a subject are imaged. Examples of medical image diagnostic devices include X-ray CT devices and MRI (Magnetic Resonance Imaging) devices. An X-ray CT apparatus generates axial cross-sectional or three-dimensional CT image data of a subject based on an electrical signal based on the X-rays detected by an X-ray detector by irradiating the subject with X-rays. The X-ray CT apparatus includes an X-ray tube and a plurality of units in a rotating section of a gantry.

Each of the plurality of units includes an intake port, an exhaust port, and a fan (also referred to as a "cooling fan") that takes in air from the intake port and exhausts the air from the exhaust port. While the rotating part is rotating, the airflow generated by the drive of the fan and the airflow generated by the rotation of the rotating part collide at the part along the rotational direction of the exhaust port, causing strong pressure fluctuations with the sound source at that part. , noise is generated.

JP 2018-29909 Publication

One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to effectively cool the devices inside the unit while suppressing the noise of the unit due to the rotation of the rotating part. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. Issues corresponding to each effect of each configuration shown in the embodiments described later can also be positioned as other issues.

The X-ray CT apparatus according to the embodiment includes an X-ray irradiation section, a plurality of units, a rotating section, and a protruding section. The X-ray irradiation unit irradiates X-rays. Each of the plurality of units is provided with an intake port, an exhaust port, and a fan for taking in air from the intake port and exhausting air from the exhaust port. The rotating section rotatably holds the X-ray irradiation section and the plurality of units. The protruding portion is provided on the upstream side of the airflow generated outside the at least one unit by the rotation of the rotating portion of the exhaust port of at least one of the plurality of units.

FIG. 1 is a schematic diagram showing the configuration of an X-ray CT apparatus according to an embodiment. FIG. 2(A) is a front view showing the configuration of each unit included in the mount device of the X-ray CT apparatus according to the embodiment, and FIG. 2(B) is a front view showing the configuration of each unit provided in the mount device of the FIG. 3 is a front view showing the external appearance of each unit. FIG. 3 is a diagram showing the effect when the unit of the X-ray CT apparatus according to the comparative example rotates. FIG. 4 is a diagram showing the effect when the unit of the X-ray CT apparatus according to the embodiment rotates. FIG. 5 is a perspective view showing a unit model when the protruding plate of the X-ray CT apparatus according to the embodiment is rectangular. FIG. 6 is a diagram showing a characteristic map of the protruding plate obtained by CFD analysis. FIG. 7 is a perspective view showing a unit model when the exhaust port of the X-ray CT apparatus according to the embodiment is circular. FIG. 8 is a diagram showing a unit in which a fan is provided at the exhaust port in the first modification of the X-ray CT apparatus according to the embodiment. FIG. 9 is a perspective view showing a unit provided with an exhaust port on the outer peripheral surface in a second modification of the X-ray CT apparatus according to the embodiment. FIG. 10 is a perspective view showing an example of application of a protruding plate to a unit in the X-ray CT apparatus according to the embodiment.

Hereinafter, embodiments of the X-ray CT apparatus will be described in detail with reference to the drawings.

The data acquisition method by the X-ray CT apparatus according to the embodiment includes a rotation/rotation (RR) method in which the X-ray source and the X-ray detector rotate around the subject as a single unit; There are various methods such as a stationary/rotate (SR) method in which a large number of detection elements are arrayed in a ring shape and only the X-ray tube rotates around the subject. The present invention is applicable to either method. Hereinafter, an X-ray CT apparatus according to an embodiment will be described, taking as an example a case where the third generation rotation/rotation method, which is currently the mainstream, is adopted.

FIG. 1 is a schematic diagram showing the configuration of an X-ray CT apparatus according to an embodiment.

FIG. 1 shows an X-ray CT apparatus 1 according to an embodiment. The X-ray CT apparatus 1 includes a gantry device 10, a bed device 30, and a medical image processing device, that is, a console device 40. The gantry device 10 acquires X-ray detection data (also referred to as "pure raw data") regarding the subject (eg, patient) P placed on the bed device 30. The console device 40 generates raw data by performing preprocessing on the detection data for a plurality of views, and reconstructs and displays CT image data by performing reconstruction processing on the raw data.

In FIG. 1, for convenience of explanation, a plurality of gantry devices 10 are drawn above and below the left side, but in actual configuration, there is only one gantry device 10.

The gantry device 10 includes an X-ray source (for example, an X-ray tube) 11, an X-ray detector 12, a rotating section (for example, a rotating frame) 13, an X-ray high voltage device 14, a control device 15, and a wedge 16, a collimator 17, a data acquisition system (DAS) 18, a heat exchanger 19 (shown in FIG. 2(A)), and a starter control circuit 20 (shown in FIG. 2(A)). A non-rotating part (for example, a fixed frame) 21 is provided. Note that the pedestal device 10 is an example of a pedestal section.

The X-ray tube 11 is provided on a rotating frame 13. The X-ray tube 11 is a vacuum tube that generates X-rays by applying a high voltage from the X-ray high-voltage device 14 to irradiate thermoelectrons from a cathode (filament) toward an anode (target). For example, the X-ray tube 11 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

In addition, in the embodiment, it can be applied to both a single-tube type X-ray CT device and a so-called multi-tube type X-ray CT device in which multiple pairs of X-ray tubes and X-ray detectors are mounted on a rotating ring. Applicable. Furthermore, the X-ray source that generates X-rays is not limited to the X-ray tube 11. For example, in place of the X-ray tube 11, examples include a focus coil that converges the electron beam generated from the electron gun, a deflection coil that electromagnetically deflects it, and a target that surrounds half the patient P and generates X-rays when the deflected electron beam collides with it. X-rays may be generated by a fifth generation system including a ring. Note that the X-ray tube 11 is an example of an X-ray irradiation unit.

The X-ray detector 12 is provided on the rotating frame 13 so as to face the X-ray tube 11 . The X-ray detector 12 detects the X-rays irradiated from the X-ray tube 11, and outputs detection data corresponding to the X-ray dose to the DAS 18 as an electrical signal. The X-ray detector 12 has, for example, a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction along one circular arc centered on the focal point of the X-ray tube 11. The X-ray detector 12 has, for example, a structure in which a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction are arranged in the slice direction (column direction, row direction).

Further, the X-ray detector 12 is, for example, an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The scintillator array includes a plurality of scintillators, and each scintillator includes a scintillator crystal that outputs light in an amount of photons corresponding to the amount of incident X-rays. The grid is disposed on the X-ray incident side of the scintillator array and has an X-ray shielding plate that has a function of absorbing scattered X-rays. Note that the grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has a function of converting the amount of light from the scintillator into an electrical signal, and includes optical sensors such as photomultiplier tubes (PMTs).

Note that the X-ray detector 12 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into electrical signals. Furthermore, the X-ray detector 12 is an example of an X-ray detection section.

The rotating frame 13 supports the X-ray tube 11 and the X-ray detector 12 so as to face each other. The rotating frame 13 is an annular frame that rotates the X-ray tube 11 and the X-ray detector 12 together under the control of a control device 15, which will be described later. Note that, in addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 may further include and support an X-ray high voltage device 14 and a DAS 18. Furthermore, the rotating frame 13 is an example of a rotating section.

In this way, the X-ray CT apparatus 1 rotates the rotating frame 13, which supports the X-ray tube 11 and the X-ray detector 12 facing each other, around the patient P, thereby providing multiple views of the patient P. Collects 360° worth of detection data. Note that the reconstruction method for CT image data is not limited to the full scan reconstruction method using 360° worth of detection data. For example, the X-ray CT apparatus 1 may employ a half-reconstruction method in which CT image data is reconstructed based on detection data for a half-circle (180°) + fan angle.

The X-ray high voltage device 14 is provided on the rotating frame 13. The X-ray high voltage device 14 has electric circuits such as a transformer and a rectifier. The X-ray high voltage device 14 includes a voltage generation unit U2 (shown in FIGS. 2A and 2B) and a voltage control unit U3 (shown in FIGS. 2A and 2B). The voltage generation unit U2 generates a high voltage to be applied to the X-ray tube 11 under the control of a control device 15, which will be described later. The voltage control unit U3 receives voltage from the voltage generation unit U2 and controls the output voltage of the X-ray tube 11 under the control of a control device 15, which will be described later. Note that in FIG. 1, for convenience of explanation, the X-ray high voltage device 14 is placed at a position in the positive direction of the x-axis with respect to the X-ray tube 11; It may be placed at a position in the direction. Note that, instead of the rotating frame 13, the X-ray high voltage device 14 may be provided on a fixed frame 21 that rotatably supports the rotating frame 13. Note that the X-ray high voltage device 14 is an example of an X-ray voltage generator.

The control device 15 includes a processing circuit, a memory, and a drive mechanism such as a motor and an actuator. The configurations of the processing circuit and memory are the same as the processing circuit 44 and memory 41 of the console device 40, which will be described later, so a description thereof will be omitted.

The control device 15 receives input signals from an input interface 43 (described later) attached to the console device 40 or an input interface (not shown) attached to the gantry device 10, and controls the operations of the gantry device 10 and the bed device 30. It has the function to perform For example, the control device 15 receives an input signal and performs control to rotate the rotating frame 13, control to tilt the gantry device 10, and control to operate the bed device 30 and the top plate 33. Note that the control for tilting the gantry device 10 is achieved by the control device 15 rotating the rotating frame 13 around the x-axis based on inclination angle (tilt angle) information input through an input interface attached to the gantry device 10. be done. Note that the control device 15 may be provided on the gantry device 10 or may be provided on the console device 40. Note that the control device 15 is an example of a control section.

The control device 15 also rotates the X-ray tube 11 based on imaging conditions input from an input interface 43 (described later) attached to the console device 40 or an input interface (not shown) attached to the gantry device 10. The angle and the operation of the wedge 16 and collimator 17, which will be described later, are controlled.

The wedge 16 is provided on the rotating frame 13 so as to be disposed on the X-ray emission side of the X-ray tube 11. The wedge 16 is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 11 under the control of the control device 15. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the patient P have a predetermined distribution. It is. For example, the wedge 16 (Wedge Filter) and bow-tie filter are filters made of aluminum processed to have a predetermined target angle and a predetermined thickness.

The collimator 17 is also called an X-ray diaphragm or a slit, and is provided on the rotating frame 13 so as to be disposed on the X-ray emission side of the X-ray tube 11. The collimator 17 is a lead plate or the like for narrowing down the irradiation range of the X-rays that have passed through the wedge 16 under the control of the control device 15, and forms an X-ray irradiation aperture by combining a plurality of lead plates or the like.

The DAS 18 is provided on the rotating frame 13. The DAS 18 includes an amplifier that performs amplification processing on the electrical signals output from each X-ray detection element of the X-ray detector 12 under the control of the control device 15, and an amplifier that amplifies the electrical signals under the control of the control device 15. It has an A/D (Analog to Digital) converter that converts into a signal, and generates detection data after amplification and digital conversion. Detection data for multiple views generated by the DAS 18 is transferred to the console device 40.

Here, the detection data generated by the DAS 18 is sent via optical communication from a transmitter having a light emitting diode (LED) provided on the rotating frame 13 to a receiver having a photodiode provided on the fixed frame 21 of the mount device 10. The message is sent and transferred to the console device 40. Note that the method of transmitting the detection data from the rotating frame 13 to the fixed frame 21 of the gantry device 10 is not limited to the above-mentioned optical communication, but any method may be used as long as it is a non-contact type data transmission.

The heat exchanger 19 is a radiator that cools the X-ray tube 11 , and is connected to a coolant flow path connected to the inside of the housing of the X-ray tube 11 . What is the heat exchanger 19, a fan (not shown) that blows air to the outer surface of the heat exchanger 19, and a pump (not shown) that circulates coolant between the housing of the X-ray tube 11 and the heat exchanger 19? A cooling unit U4 (shown in FIG. 2(A)) is configured. The heat exchanger 19 performs heat exchange between the coolant and the outside air, thereby cooling the coolant heated by the X-ray tube 11. Furthermore, heat exchange in the heat exchanger 19 is promoted by the air blowing from the fan. The cooling unit U4 can suppress the temperature of the X-ray tube 11 within a predetermined range by controlling the rotation speed of the pump and fan according to the temperature of the X-ray tube 11.

The starter control circuit 20 adjusts the rotation speed of the rotating anode target by controlling the amount of current supplied to the stator coil that rotates the rotating anode target of the X-ray tube 11 . The starter control circuit 20 constitutes a starter unit U5 (shown in FIG. 2(A)).

The bed device 30 includes a base 31, a bed driving device 32, a top plate 33, and a support frame 34. The bed device 30 is a device on which a patient P to be scanned is placed and moves the patient P under the control of the control device 15.

The base 31 is a housing that supports the support frame 34 movably in the vertical direction (y-axis direction). The bed driving device 32 is a motor or an actuator that moves the top plate 33 on which the patient P is placed in the longitudinal direction of the top plate 33 (z-axis direction). The top plate 33 provided on the upper surface of the support frame 34 is a plate having a shape on which the patient P can be placed.

In addition to the top plate 33, the bed driving device 32 may move the support frame 34 in the longitudinal direction of the top plate 33 (z-axis direction). Further, the bed driving device 32 may move the base 31 of the bed device 30 together. When the present invention is applied to standing CT, a method may be adopted in which a patient moving mechanism corresponding to the top plate 33 is moved. Furthermore, when performing imaging that involves a relative change in the positional relationship between the imaging system of the gantry device 10 and the top plate 33, such as scano-imaging for helical scanning or positioning, the relative change in the positional relationship is This may be performed by driving the top plate 33, by moving the fixed frame 21 of the gantry device 10, or by a combination thereof.

In the embodiment, the rotation axis of the rotation frame 13 in a non-tilted state or the longitudinal direction of the top plate 33 of the bed device 30 is the z-axis direction, and the axial direction perpendicular to the z-axis direction and horizontal to the floor surface is the z-axis direction. The axial direction that is perpendicular to the x-axis direction and the z-axis direction and perpendicular to the floor surface is defined as the y-axis direction.

The console device 40 includes a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as being separate from the gantry device 10, the gantry device 10 may include the console device 40 or a part of each component of the console device 40. Further, in the following description, it is assumed that the console device 40 executes all functions with a single console, but these functions may be executed with a plurality of consoles. The console device 40 controls the operation of the gantry device 10 to acquire detection data for a plurality of views, and generates CT image data based on the detection data. Note that the console device 40 is an example of a medical image processing device.

The memory 41 is configured by, for example, a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, or the like. The memory 41 may be configured by a portable medium such as a USB (Universal Serial Bus) memory and a DVD (Digital Video Disk). The memory 41 stores various processing programs (including application programs as well as an OS (Operating System), etc.) used in the processing circuit 44 and data necessary for executing the programs. Further, the OS may include a GUI (Graphic User Interface) that makes extensive use of graphics to display information on the display 42 to the operator and allows basic operations to be performed using the input interface 43.

The memory 41 stores, for example, detection data sent from the DAS 18, raw data after preprocessing and before reconstruction, and CT image data after reconstruction based on the raw data. Pre-processing means at least one of logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, beam hardening processing, etc. on the detected data. Further, a cloud server connectable to the X-ray CT apparatus 1 via a communication network such as the Internet is configured to store detection data, raw data, or CT image data upon receiving a storage request from the X-ray CT apparatus 1. may be done. Note that the memory 41 is an example of a storage section.

The display 42 displays various information. For example, the display 42 outputs CT image data generated by the processing circuit 44 and a GUI for accepting various operations from an operator. For example, the display 42 is a liquid crystal display, a CRT (Cathode Ray Tube) display, an OLED (Organic Light Emitting Diode) display, or the like. Further, the display 42 may be provided on the gantry device 10. Further, the display 42 may be of a desktop type, or may be constituted by a tablet terminal or the like that can communicate wirelessly with the main body of the console device 40. Note that the display 42 is an example of a display section.

The input interface 43 includes an input device that can be operated by an operator such as a technician, and an input circuit that inputs signals from the input device. Input devices include mice, keyboards, trackballs, switches, buttons, joysticks, touchpads that perform input operations by touching the operating surface, touchscreens that integrate the display screen and touchpad, and non-control devices that use optical sensors. This is realized by a touch input circuit, a voice input circuit, etc. When the input device receives an input operation from the operator, the input circuit generates an electrical signal according to the input operation and outputs it to the processing circuit 44 . Further, the input interface 43 may be provided in the gantry device 10. Furthermore, the input interface 43 may be configured with a tablet terminal or the like that can communicate wirelessly with the console device 40 main body. Note that the input interface 43 is an example of an input section.

Note that the console device 40 may include a network interface (not shown). The network interface is composed of connectors that meet parallel connection specifications and serial connection specifications. When the X-ray CT apparatus 1 is installed on a medical imaging system, the network interface sends and receives information to and from external devices on the network. For example, under the control of the processing circuit 44, the network interface receives an examination order related to a CT examination from an external device, and also receives detection data acquired by the X-ray CT apparatus 1, raw data generated, or a CT image. Send data to an external device.

The processing circuit 44 controls the overall operation of the X-ray CT apparatus 1. The processing circuit 44 refers to a dedicated or general-purpose CPU (Central Processing Unit), MPU (Micro Processor Unit), or GPU (Graphics Processing Unit), as well as an ASIC, a programmable logic device, and the like. Examples of programmable logic devices include simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs). Can be mentioned.

Further, the processing circuit 44 may be configured by a single circuit, or may be configured by a combination of a plurality of independent processing circuit elements. In the latter case, the memory 41 may be provided individually for each processing circuit element, or a single memory 41 may store programs corresponding to the functions of a plurality of processing circuit elements. Note that the processing circuit 44 is an example of a processing section.

Each unit provided in the gantry device 10 of the X-ray CT apparatus 1 will be explained using FIGS. 2(A) and 2(B).

As shown in FIG. 2A, the rotating frame 13 of the gantry device 10 includes an X-ray tube 11, a wedge 16, a detector unit U1, a voltage generation unit U2, a voltage control unit U3, and a cooling unit U4. and starter unit U5 are held rotatably in the direction of the arrow in FIG. 2(A) (which may be in the opposite direction of the arrow). In addition, in FIG. 2(A), for convenience of explanation, the voltage generation unit U2 and the voltage control unit U3 are arranged in the positive direction of the x-axis with respect to the X-ray tube 11, and the cooling unit U4 and the starter unit Although U5 is arranged at a position in the negative direction of the x-axis with respect to the X-ray tube 11, it may be arranged at a position where the positive and negative directions are reversed.

Detector unit U1 includes an X-ray detector 12 that detects X-rays and a DAS 18. The voltage generation unit U2 and the voltage control unit U3 constitute an X-ray high voltage device 14. The cooling unit U4 includes a heat exchanger 19, a fan (not shown) that blows air to the outer surface of the heat exchanger 19, and a pump (not shown) that circulates cooling fluid between the housing of the X-ray tube 11 and the heat exchanger 19. (not shown). Starter unit U5 includes a starter control circuit 20. Note that the rotating frame 13 may be rotatably provided with a cooling unit (not shown) for cooling the X-ray detector 12 in addition to the cooling unit U4 for cooling the X-ray tube 11.

The units U1 to U5 are provided with an intake port and an exhaust port on the outer wall of their casings. Each of the units U1 to U5 is provided with a fan for taking in air from an intake port and exhausting air from an exhaust port. For example, all or part of the units U1 to U5 can be configured such that a fan F is provided at the intake port (as shown in FIG. 4(A)), and air is sucked into the unit from the intake port by driving the fan F at the intake port. Exhaust air from the unit through the exhaust port. Further, for example, all or part of the units U1 to U5 may be provided with a fan F at the exhaust port (as shown in FIGS. 8(A) and 8(B) of the first modification), and the exhaust may be exhausted by driving the fan at the exhaust port. By exhausting air outside the unit through the mouth, air is taken into the unit through the intake port. Unless otherwise specified, all or some of the units U1 to U5 will be described with a fan F provided at the intake port (as shown in FIG. 4(A)).

Further, as shown in FIG. 2(B), one or more exhaust ports Ce are provided on the side surface (xy plane) of at least one of the units U1 to U5 (in FIG. 2(B), the units U1 to U5 are provided with one or more exhaust ports Ce). (Example: one exhaust port Ce for each U5). A protrusion, for example a protrusion plate M, is provided on the upstream side of the airflow generated outside the unit U by the rotation of the rotating frame 13 of the exhaust port Ce. For example, the protruding plate M may be provided in all of the units U1 to U5. Note that at least one of the units U1 to U5 is defined as a "unit U." The purpose and effect of providing the protruding plate M, and the size and position of the protruding plate M will be explained next.

3 and 4 are diagrams for explaining the purpose and effect of providing the protruding plate M on the unit U. FIG. 3(A) is a sectional view (II sectional view of FIG. 2(B)) showing the action when the unit U' according to the comparative example rotates, and FIG. It is a perspective view which shows the effect|action when the unit U' rotates.

FIGS. 3A and 3B show a unit U' according to a comparative example without a protrusion. The unit U' includes an intake port Cs provided on one side, an exhaust port Ce provided on the other opposing side, and a fan F provided on the intake port Cs or the exhaust port Ce (in FIG. 3, a fan F provided on the intake port Cs). A fan F) is provided. While the rotating frame 13 (shown in FIG. 2B) rotates around the z-axis, an airflow G1' generated by the drive of the fan F and an airflow G2' generated by the rotation of the rotating frame 13 are generated. The airflow G1' is constantly generated to cool the heat source (for example, a device) within the unit U' even when the rotating frame 13 is stationary (standby state). On the other hand, the airflow G2' is a flow that is generated relative to the outer periphery of the unit U' due to the rotation of the rotating frame 13, and its speed is proportional to the rotational speed of the rotating frame 13 and the distance from the rotation axis.

As shown in FIG. 3B, the airflow G1' generated by the drive of the fan F and the airflow G2' generated by the rotation of the rotating frame 13 collide at a portion along the rotational direction of the exhaust port Ce. The collision causes strong pressure fluctuations with the sound source at that part, resulting in the generation of noise.

Therefore, in order to reduce the noise, the unit U shown in FIG. For example, a protruding plate M is provided. FIG. 4(A) is a cross-sectional view (II cross-sectional view of FIG. 2(B)) showing the effect when the unit U rotates, and FIG. 4(B) is a cross-sectional view showing the effect when the unit U rotates. FIG. Note that the protruding portion is not limited to the protruding plate M having a rectangular parallelepiped shape. For example, the protrusion may have a truncated quadrangular pyramid shape.

As shown in FIGS. 4(A) and 4(B), the unit U has an intake port Cs provided on one side, an exhaust port Ce provided on the other opposing side, and an intake port Cs or an exhaust port Ce. A fan F (in FIG. 4, a fan F provided at the intake port Cs) is provided. Note that the number of each of the intake ports Cs, exhaust ports Ce, and fans F provided in the unit U is not limited to one, but is usually plural. Furthermore, although the exhaust port Ce is shown as being rectangular, the exhaust port Ce may be circular (as shown in FIG. 7) or may be a collection of a plurality of slits (as shown in FIG. 10(B)). ), or may have a rectangular shape with chamfered four corners.

While the rotary frame 13 is rotating around the z-axis, the protruding plate M separates the airflow G2' (shown in FIG. 3) generated by the rotation to generate an airflow G2. Since the protruding plate M can suppress the airflow G2' to the portion along the rotational direction of the exhaust port Ce, it is possible to suppress the noise caused by the collision of the airflows described above. In addition, by generating the airflow G2, it is possible to generate a negative pressure region R over the entire back surface (downstream side) of the protruding plate M including the vicinity of the exhaust port Ce of the unit U. Therefore, the airflow G1 flowing into the negative pressure region R from the exhaust port Ce can be increased, so that the airflow G1 flowing into the unit U from the intake port Cs can be increased by driving the fan F. In this way, according to the protruding plate M, the area around the exhaust port Ce of the unit U assists the airflow G1 passing through the unit U due to the effect of the negative pressure region R generated by the protruding plate M. The amount of passing air can be increased. In other words, the cooling efficiency of the devices within the unit U is improved.

In this way, the protruding plate M can suppress the noise caused by the collision of the airflows described above. In addition, according to the protruding plate M, the cooling efficiency of the devices in the unit U can be improved by increasing the amount of air passing through the unit U.

FIG. 5 is a perspective view showing a unit model for designing the size and position of the protruding plate M when the protruding plate M is rectangular.

It is preferable that the width W of the protruding plate M shown in FIG. 5 is equal to or longer than the width B of the exhaust port. The position of the width W of the protruding plate M is preferably such that the center of the width W of the protruding plate M has substantially the same trajectory as the center of the width B of the exhaust port when the rotating frame 13 rotates. It is. This is to suppress the airflow to the portion along the rotational direction of the exhaust port Ce, and to suppress the noise caused by the collision of the airflows described above. Further, the design of the height (protrusion length) L of the protrusion plate M and the position in the rotational direction (distance D from the exhaust port Ce) will be described next.

In order to find a suitable height L of the protruding plate M and a distance D from the exhaust port Ce, a unit U equipped with a fan F is modeled, and while the fan F is driven, the rotating frame 13 is rotated around the unit U. CFD (Computational Fluid Dynamic) analysis was performed in a state where relative airflow was generated.

As the rotational speed of the rotating frame 13 increases, the negative pressure increases, which leads to a further increase in the amount of air passing through the unit U, but the noise caused by the collision of the airflows described above increases. Therefore, CFD analysis was performed using a case of high-speed rotation, for example, 4 [rotations/second] (=0.25 [seconds/rotation]), which has poor conditions for noise. Therefore, when the rotation speed of the rotating frame 13 is 4 [revolutions/second] or less, at least relational expressions (1) and (2) can be applied.

FIG. 6 is a diagram showing a characteristic map of the protruding plate M obtained by CFD analysis. FIG. 6(A) shows the amount of air passing through the unit U when the horizontal axis is D/A and the vertical axis is L/A. FIG. 6(B) shows the acoustic power level of the unit U when the horizontal axis is D/A and the vertical axis is L/A. Note that "A" is the length of the exhaust port Ce in the rotational direction, and "B" is the length of the rotating frame 13 (shown in FIG. 2(B)) in the radial direction.

The passing air volume of the unit U with the protruding plate M shown in FIG. 6(A) is a value when the passing air volume of the unit U' without the protruding plate M according to the comparative example is set to 1 as a reference. The acoustic power level of the unit U shown in FIG. 6(B) was normalized as a relative value of the level with respect to the case of the unit U' according to the comparative example. The relative value of the acoustic power level obtained is the ratio of the acoustic power resulting from pressure fluctuations (noise generation source) on the wall surface of unit U for unit U′ to that for unit U. This is a logarithmic value. As shown in FIG. 6(A), since the flow rate of air passing through unit U is always 1 or more, the flow rate passing through unit U increases by installing it regardless of the size and position (distance D) of protruding plate M. I know that.

On the other hand, as shown in FIG. 6(B), the acoustic power level of the unit U is lower than that of the comparative example in the broken line area, and the noise is reduced, but in other areas (close to the exhaust port Ce and the height of the protruding plate M is It was found that it increases in the high range). From this result, the following relational expressions (1) and (2), which refer to the broken line area, are obtained. If the parameters indicating the size and position of the protruding plate M satisfy either relational expressions (1) or (2), the volume of the airflow G1 can be increased while reducing the noise caused by the collision described above.
0<L/A≦0.4 and 0<D/A<0.35…(1)
L/A>0 and D/A≧0.35…(2)

Note that when the rotational speed is lower than the above-mentioned 4 [rotations/second], it is thought that the noise caused by the collision of airflows becomes smaller. Therefore, when the rotation speed is lower than 4 revolutions/second, the parameter range for achieving the same effect as high speed becomes narrower. Therefore, as the rotation speed decreases from 4 [revolutions/second], "0.4" in the above relational expression (1) is set to become smaller as "0.3", "0.2", etc. , as the rotation speed decreases from 4 [revolutions/second], "0.35" in the above relational expressions (1) and (2) increases to "0.4", "0.5", etc. May be set.

The preferred size and position of the protruding plate M when the exhaust port Ce (and intake port Cs) of the unit U is rectangular have been explained using FIG. The position does not apply only when the exhaust port Ce is rectangular. For example, the determined suitable size and position of the protruding plate M can be applied even when the exhaust port Ce is circular (including an ellipse). FIG. 7 is a perspective view showing a unit model when the exhaust port Ce is circular. When the protruding plate M is circular, "A" is the maximum length (diameter) of the exhaust port Ce in the rotational direction, and "B" is the maximum length (diameter) of the rotating frame 13 (shown in FIG. 2(B)) in the radial direction. It is the length (diameter).

As described above, by providing the protruding plate M of a predetermined size at a predetermined position of the unit U, it is possible to effectively cool the devices in the unit U while suppressing the noise of the unit U caused by the rotation of the rotating frame 13. .

(First modification)
Although FIGS. 4A and 4B illustrate the case where the fan F is provided at the intake port Cs of the unit U, the present invention is not limited to that case. For example, the unit U may include a fan F at the exhaust port Ce. This case is illustrated in FIG.

FIG. 8 is a diagram showing a unit U in which a fan F is provided at the exhaust port Ce in the first modification. FIG. 8(A) is a sectional view (II sectional view of FIG. 2(B)) of the unit U when the fan F does not protrude from the exhaust port Ce, and FIG. 8(B) is a sectional view of the unit U when the fan F does not protrude from the exhaust port Ce. FIG. 2 is a cross-sectional view (II cross-sectional view of FIG. 2(B)) of the unit U when it protrudes from the exhaust port Ce.

As shown in FIGS. 8(A) and 8(B), the unit U is provided with a fan F at the exhaust port Ce. While the rotary frame 13 is rotating about the z-axis, the protruding plate M separates the airflow G2' (shown in FIG. 3) generated by the rotation to generate an airflow G2. Since the airflow G2' to the portion along the rotational direction of the exhaust port Ce can be suppressed, the noise caused by the collision of the airflows mentioned above can be suppressed. In addition, by generating the airflow G2, it is possible to generate a negative pressure region R over the entire back surface (downstream side) of the protruding plate M including the vicinity of the exhaust port Ce of the unit U. Therefore, since the airflow G1 flowing into the negative pressure region R from the exhaust port Ce can be increased by driving the fan F, the airflow G1 flowing into the unit U from the intake port Cs can be increased. In this way, according to the protruding plate M, the area around the exhaust port Ce of the unit U assists the airflow G1 passing through the unit U by the effect of the negative pressure generated by the protruding plate M, thereby reducing the amount of air passing through the unit U. can be increased.

In this manner, the protruding plate M can suppress the noise caused by the collision of the airflows described above, and can assist the airflow G1 passing through the unit U to increase the amount of air passing through the unit U.

In addition, in FIG. 8(A), when the fan F is provided at the exhaust port Ce, the suitable size and position of the protruding plate M may be the same as those described above using FIGS. 5 and 6. On the other hand, in FIG. 8(B), when the fan F is provided at the exhaust port Ce, the suitable size and position of the protruding plate M may be the same as those described above using FIGS. 5 and 6. The height L of the protruding plate M may be determined from the exhaust side surface of the fan F in consideration of the height of the fan F.

(Second modification)
Although FIGS. 4A and 4B illustrate the case where the exhaust port Ce is provided on the side surface of the unit U, the present invention is not limited to that case. For example, the unit U may be provided with an exhaust port Ce on its outer peripheral surface (or inner peripheral surface). This case is illustrated in FIG.

FIG. 9 is a perspective view showing a unit U in which an exhaust port Ce is provided on the outer circumferential surface in a second modification.

As shown in FIG. 9, the unit U is provided with an exhaust port Ce on the outer peripheral surface of the unit U. In this case as well, according to the protruding plate M, it is possible to suppress the noise caused by the collision of the airflows described above, and also to assist the airflow G1 passing through the unit U to increase the amount of air passing through the unit U. can.

In addition, in the case where the exhaust port Ce is provided on the outer peripheral surface of the unit U, the suitable size and position of the protruding plate M may be the same as those described above using FIGS. 5 and 6. Further, similarly to the exhaust port Ce, the intake port Cs may also be provided on a surface other than the side surface of the unit U. For example, the intake port Cs may be provided on the inner peripheral surface of the unit U, while the exhaust port Ce may be provided on the side surface or outer peripheral surface of the unit U, or the intake port Cs may be provided on the outer peripheral surface of the unit U. On the other hand, the exhaust port Ce may be provided on the side surface or inner peripheral surface of the unit U.

(Application example of protruding plate M)
An example of application of the protruding plate M to the unit U will be described using FIG. 10.

FIG. 10 is a diagram showing an example of application of the protruding plate M to the unit U. FIG. 10(A) is a perspective view showing a detector unit U1 as a unit U to which a protruding plate M is applied. FIG. 10(B) is a perspective view showing a voltage generating unit U2 as a unit U to which a protruding plate M is applied.

As shown in FIG. 10(A), the detector unit U1 includes five intake ports Cs on its inner peripheral surface and four exhaust ports Ce (not shown) on its side surface. Furthermore, a fan (that is, an exhaust fan) F is provided at each of the four exhaust ports Ce. An airflow G1 is generated by driving the fan F. Furthermore, since the airflow G2 is generated by the Z-axis rotation of the rotating frame 13 (shown in FIG. 2(B)), the detector unit U1 has a ) A protruding plate M is provided on the upstream side of the airflow G2 generated in the air flow G2. Note that the suitable size and position of the protruding plate M may be the same as those described above using FIGS. 5 and 6. Further, the height L of the protruding plate M is determined from the exhaust side surface of the fan F in consideration of the height of the fan F, as described using FIG. 8(B).

As shown in FIG. 10(B), the voltage generation unit U2 includes two intake ports Cs (not shown) on one side thereof, and two exhaust ports Ce on the other opposing side. Further, a fan (that is, an intake fan) F is provided at each of the two intake ports Cs. An airflow G1 is generated by driving the fan F. Further, since the airflow G2 is generated by the Z-axis rotation of the rotating frame 13 (shown in FIG. 2(B)), the voltage generation unit U2 is configured to operate the external (side ) A protruding plate M is provided on the upstream side of the airflow G2 generated in the air flow G2. Note that the suitable size and position of the protruding plate M may be the same as those described above using FIGS. 5 and 6. Further, as shown in FIG. 10(B), the two exhaust ports Ce of the voltage generation unit U2 may be configured by an aggregate of a plurality of slits.

According to at least one embodiment described above, the devices in the unit U can be effectively cooled while suppressing the noise of the unit U caused by the rotation of the rotating frame 13.

In addition, the amount of air passing through the unit U can be increased by the protruding plate M. Therefore, in order to secure the air volume necessary for cooling the devices in unit U, it is necessary to increase the rotation speed of fan F installed in unit U, increase the size of fan F, or increase the number of fans F themselves. Therefore, increases in noise, power consumption, cost, and weight of the rotating frame 13 can be suppressed. Another way of thinking is that the installation of the protruding plate M also leads to easing the design of other functions to compensate for the increase in air volume. Specifically, examples include suppressing the power consumption of the motor of the fan F provided in the unit U, reducing the noise of the fan F, and designing the unit U to be smaller/higher density.

Although several embodiments have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, changes, and combinations of embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

1... X-ray CT device 10... Frame device 11... X-ray tube 12... X-ray detector 13... Rotating frame 14... X-ray high voltage device 18... DAS
40...Console device (medical image processing device)
M... Projection plate U... At least one unit U1... Detector unit U2... Voltage generation unit U3... Voltage control unit U4... Cooling unit U5... Starter unit

Claims (5)

an X-ray irradiation unit that irradiates X-rays;
a plurality of units including an intake port, an exhaust port, and a fan for taking in air from the intake port and exhausting the air from the exhaust port;
a rotating section that rotatably holds the X-ray irradiation section and the plurality of units;
a protrusion of the exhaust port of at least one of the plurality of units, provided on the upstream side of an airflow generated outside the at least one unit by rotation of the rotating section;
An X-ray CT device. When the distance between the protrusion provided in the at least one unit and the exhaust port of the unit is D, the height of the protrusion is L, and the length of the exhaust port in the rotational direction is A,
The protrusion provided on the at least one unit is
0<L/A≦0.4 and 0<D/A<0.35,
L/A>0 and D/A≧0.35
Equipped with a configuration that satisfies any of the following.
The X-ray CT apparatus according to claim 1. The exhaust ports provided in each of the plurality of units are provided on an outer circumferential surface, an inner circumferential surface, or a side surface of the unit,
The X-ray CT apparatus according to claim 1. Each of the plurality of units is provided with the fan at the exhaust port or the intake port,
The X-ray CT apparatus according to claim 1. The plurality of units are
a detector unit including an X-ray detector that detects the X-rays;
a voltage generation unit including an inverter that generates voltage;
a voltage control unit that receives the voltage and controls the output voltage of the X-ray irradiation section;
cooling unit;
starter unit and
The X-ray CT apparatus according to any one of claims 1 to 4.

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