JP2020153734A - Medical diagnostic imaging device and method of generating image for inspection - Google Patents

Abstract

To provide a medical diagnostic imaging device in which start-up inspection of a gamma-ray detector can be performed without using an RI (Radio Isotope).SOLUTION: The medical diagnostic imaging device comprises an X-ray tube 32, an X-ray detector 33, and a gamma-ray detector 23, and a generation unit. The X-ray tube radiates an X ray. The X-ray detector detects the X ray radiated from the X-ray tube. The gamma-ray detector detects a gamma ray emitted from a radioactive source administered to a subject. The generation unit generates image data by detecting the X ray radiated from the X-ray tube with the gamma-ray detector.SELECTED DRAWING: Figure 4

Description

Embodiments of the present invention relate to a medical diagnostic imaging apparatus and an inspection image generation method.

Recently, a composite device (hereinafter referred to as SPECT-CT device) that integrates an X-ray CT (Computed Tomography) device that reconstructs a morphological image and a SPECT (Single Photon Emission computed Tomography) device that reconstructs a functional image has been developed. Has been done.

According to the SPECT-CT apparatus, the subject can undergo two types of tests in one test, so that the burden on the subject can be reduced. Further, since the user can simultaneously refer to the morphological image and the functional image relating to the same part of the subject, it is possible to perform highly accurate image diagnosis.

By the way, if the gamma ray detector of the SPECT device fails to take an image after administration of the radiopharmaceutical, the subject is exposed to unnecessary radiation and the quality of medical service is deteriorated. In addition, if an artifact occurs in the scintigram due to a defective gamma ray detector, a misdiagnosis without the user's knowledge will lead to a medical accident. Therefore, in order to control the quality of the gamma ray detector, it is preferable to perform a daily inspection (hereinafter referred to as a start-up inspection) at the start of the SPECT apparatus. The inspection items in the SPECT device start-up inspection include, for example, the energy peak due to the nuclide used and the abnormal accumulation of the gamma ray detector, the presence or absence of defects, the uniformity, and the center of rotation, which are presented in the guidelines for prevention of nuclear medicine medical treatment accidents of the Japanese Society of Nuclear Medicine. For example, visual recognition of misaligned images.

However, this type of start-up inspection, which is performed every time the SPECT device is started, is performed using a vial or syringe containing a solution of a radioactive isotope (Radio Isotope, hereinafter referred to as RI), which is a radiation source for the start-up inspection. .. For this reason, the technician needs to be present to install a radiation source for the start-up inspection at each start-up inspection, and is exposed to the radiation source at each start-up inspection. In addition, as the radiation source for the start-up inspection, a radiation source with the same dose as the RI administered to the subject at the time of normal imaging is used, so it takes time for the count number required for imaging to be accumulated. Therefore, it may take a long time from 30 minutes to sometimes 1 hour or more. In addition, since the RI is prepared every time as a radiation source for the start-up inspection, the start-up inspection is costly.

U.S. Pat. No. 8049175

An object to be solved by the present invention is to perform a start-up inspection of a gamma ray detector without using RI.

The medical image diagnostic apparatus according to the embodiment includes an X-ray tube, an X-ray detector, a gamma ray detector, and a generation unit. The X-ray tube irradiates X-rays. The X-ray detector detects the X-rays emitted from the X-ray tube. The gamma ray detector detects gamma rays emitted from a radiation source administered to a subject. The generation unit generates image data by detecting X-rays emitted from an X-ray tube with a gamma ray detector.

The external view which shows an example of the SPECT-CT apparatus which concerns on one Embodiment. The block diagram which shows one configuration example of a SPECT-CT apparatus. The explanatory view which shows an example of the case where an X-ray detector detects X-rays emitted from an X-ray tube. Explanatory drawing which shows an example of the 1st method of inspection imaging which concerns on this embodiment. (A) is an explanatory diagram showing an example of the second method of inspection imaging according to the present embodiment, and (b) is an explanatory diagram showing another example of the second method of inspection imaging according to the present embodiment. Explanatory drawing which shows an example of SPECT image for inspection. (A) is an explanatory diagram showing a first modification of the first method and a second method of inspection imaging, and (b) is an explanation showing a second modification of the first method and the second method of inspection imaging. Figure. The figure for demonstrating the inspection imaging for confirming the rotation center deviation. The flowchart which shows an example of the procedure at the time of performing the start-up inspection of the gamma ray detector by the SPECT-CT apparatus which concerns on this embodiment without using RI.

Hereinafter, embodiments of the medical image diagnostic apparatus and the inspection image generation method will be described in detail with reference to the drawings.

In the following description, an example of a case where a composite device (SPECT-CT device) of a SPECT device and an X-ray CT device is used as the medical image diagnostic device according to the embodiment will be shown.

FIG. 1 is an external view showing an example of a SPECT-CT apparatus 10 according to an embodiment. Further, FIG. 2 is a block diagram showing a configuration example of the SPECT-CT apparatus 10.

The SPECT-CT device 10 includes a gamma ray scanner device 20, an X-ray scanner device 30, a console 50, and a sleeper device 40. The SPECT-CT apparatus 10 is an example of a medical diagnostic imaging apparatus. The console 50 may be connected to the gamma ray data acquisition circuit 24 and the X-ray data acquisition circuit 34 so as to be able to transmit and receive data, and may not be provided in the same room or building as the gamma ray scanner device 20 and the X-ray scanner device 30. Good.

As shown in FIG. 1, the gamma ray scanner device 20 and the X-ray scanner device 30 have a SPECT mount 21 and an X-ray CT mount 31, respectively. The SPECT pedestal 21 and the X-ray CT pedestal 31 each have cylindrical hollow portions 21a and 31a to which the top plate 41 is transferred. Further, the SPECT pedestal 21 has a rotary pedestal and a fixed pedestal that rotatably supports the rotary pedestal. The X-ray CT pedestal 31 also has a rotary pedestal and a fixed pedestal.

As shown in FIG. 1, in the present embodiment, the longitudinal direction of the top plate 41 of the sleeper device 40 is orthogonal to the z-axis direction and the z-axis direction, and the axial direction horizontal to the floor surface is the x-axis direction. It is assumed that the axial directions orthogonal to the z-axis direction and perpendicular to the floor surface are defined as the y-axis directions.

The gamma-ray scanner device 20 includes a collimator 22, a gamma-ray detector 23 to which the collimator 22 is detachably provided, and a gamma-ray data collection circuit 24 in a SPECT stand 21 (see FIG. 2).

The gamma ray scanner device 20 has the same configuration as, for example, a gamma ray detector rotation type SPECT device. FIG. 1 shows an example in which the gamma ray scanner device 20 has a configuration similar to that of the two-detector type gamma ray detector rotating SPECT device, but even if the number of gamma ray detectors is one or three or more. Good.

The collimator 22 is made of a substance such as lead or tungsten that is difficult to transmit radiation, and is provided with an opening for defining the incident angle of photons. The spatial resolution and sensitivity of the gamma ray scanner device 20 vary depending on the type of collimator 22. The type of collimator 22 differs depending on the thickness of the partition wall, the number of openings, the field of view, the focal position, and the like. Examples of the types of collimators 22 that can be used in the gamma ray detector 23 include parallel hole collimators, fan beam collimators, cone beam collimators, non-point aberration type collimators, pinhole collimators, diverging collimators, converging collimators, slant hole collimators, and the like. Various things can be used.

The two gamma ray detectors 23 are held by the rotating pedestal of the SPECT pedestal 21. As the rotary pedestal rotates around a predetermined rotation axis r (around the z-axis), the two gamma ray detectors 23 integrally rotate around the rotation axis r. The rotary pedestal has a rotary plate that is rotatably supported with respect to the fixed pedestal. The gamma ray detector 23 is held by the rotating plate of the rotating pedestal. The fixed pedestal is composed of a housing fixed to the base. The rotary and fixed mounts are covered, for example, by a mount cover. A hollow portion 21a including an imaging region is provided in the central portion of the rotary pedestal, the fixed pedestal, and the pedestal cover that covers them.

The gamma ray detector 23 detects gamma rays emitted from RI (radioactive isotope, radiation source) such as technetium administered to a subject (for example, a patient). The gamma ray detector 23 may be a scintillator type detector or a semiconductor type detector.

When the gamma ray detector 23 is a scintillator type detector, the gamma ray detector 23 emits a scintillator that emits a momentary flash when a gamma ray collimated by the collimator 22 is incident, a light guide, and light emitted from the scintillator. It has a plurality of photomultiplier tubes arranged in two dimensions for detection, an electronic circuit for a scintillator, and the like. The scintillator is composed of, for example, thallium-activated sodium iodide NaI (Tl).

In the electronic circuit for scintillator, each time an event in which gamma rays are incident occurs, information on the incident position of gamma rays in a detection surface composed of a plurality of photomultiplier tubes based on the outputs of the plurality of photomultiplier tubes. (Position information), incident intensity information, and incident time information are generated and output to the processing circuit 55 of the console 50. This position information may be information on two-dimensional coordinates in the detection surface, or the detection surface is virtually divided into a plurality of division areas (primary cells) in advance (for example, divided into 128 × 128 pieces). However, it may be information indicating which primary cell was incident.

On the other hand, when the gamma ray detector 23 is a semiconductor type detector, the gamma ray detector 23 is a plurality of semiconductor elements for gamma ray detection arranged in two dimensions for detecting gamma rays collimated by the collimator 22 (hereinafter referred to as “semiconductor elements”). It has a semiconductor element) and an electronic circuit for semiconductors. The semiconductor element is composed of, for example, CdTe or CdZnTe (CZT).

Each time an event in which gamma rays are incident occurs, the semiconductor electronic circuit generates incident position information, incident intensity information, and incident time information based on the output of the semiconductor element and outputs the incident position information, the incident intensity information, and the incident time information to the processing circuit 55. This position information is information indicating which semiconductor element among a plurality of semiconductor elements (for example, 128 × 128) is incident.

That is, the gamma ray detector 23 outputs incident position information, incident intensity information, and incident time information for each event. Further, the position information is at least one of the information indicating which position of the primary cell the gamma ray is incident on and the information of the two-dimensional coordinates in the detection plane.

In the gamma ray detector 23, the imaging timing is controlled by the processing circuit 55.

The gamma ray data acquisition circuit 24 is composed of, for example, a printed circuit board, is controlled by a processing circuit 55, collects the output of each of the two gamma ray detectors 23, for example, in list mode, and outputs the collected projection data to the console 50. To do. In the list mode, the gamma ray detection position information, intensity information, information indicating the relative position between the gamma ray detector 23 and the subject (position and angle of the gamma ray detector 23, etc.), and the gamma ray detection time are for each gamma ray incident event. Collected in.

On the other hand, the X-ray scanner device 30 has an X-ray tube 32, an X-ray movable throttle 32a, an X-ray detector 33, and an X-ray data acquisition circuit 34 in the X-ray CT frame 31.

The X-ray tube 32 is a vacuum tube that generates X-rays by irradiating thermoelectrons from a cathode (filament) toward an anode (target) by applying a high voltage from a high voltage device.

The X-ray scanner device 30 may have the same configuration as the one-tube type X-ray CT device, or a plurality of pairs of an X-ray tube and a detector are mounted on a rotating ring, so-called many. It may have the same configuration as that of a tube-type X-ray CT apparatus. Further, the hardware that generates X-rays is not limited to the X-ray tube 32. For example, instead of the X-ray tube 32, an X-ray is generated by a collision between a focus coil that focuses an electron beam generated from an electron gun, a deflection coil that electromagnetically deflects an electron beam, and an electron beam that surrounds and deflects a half circumference of a subject. X-rays may be generated using the same configuration as that of the 5th generation CT including the target ring to be generated.

The X-ray movable diaphragm 32a is a lead plate or the like for narrowing the irradiation range of X-rays, and a slit is formed by a combination of a plurality of lead plates or the like. The X-ray movable diaphragm 32a is controlled by the processing circuit 55 to change the X-ray irradiation range.

For example, the X-ray movable diaphragm 32a can be positioned at a position where the X-rays emitted from the X-ray tube 32 are directed toward the X-ray detector 33. Further, the X-ray movable diaphragm 32a according to the present embodiment can be positioned at a position where the X-rays emitted from the X-ray tube 32 are directed toward the gamma ray detector 23.

The X-ray detector 33 detects X-rays irradiated from the X-ray tube 32 and passed through the subject, and outputs an electric signal corresponding to the X-ray dose to the DAS 18. The X-ray detector 33 has a plurality of X-ray detection element trains in which a plurality of X-ray detection elements are arranged in the channel direction along one arc centering on the focal point of the X-ray tube 32. Further, the X-ray detector 33 has a structure in which a plurality of X-ray detection element sequences in which a plurality of X-ray detection elements are arranged in the channel direction are arranged in a slice direction (column direction, row direction) (for example, 320 rows). Have.

Further, the X-ray detector 33 is an indirect conversion type detector having, for example, a grid, a scintillator array, and an optical sensor array. The scintillator array has a plurality of scintillators, and the scintillator has a scintillator crystal that outputs a photon amount of light according to an incident X dose. The grid is arranged on the surface of the scintillator array on the X-ray incident side, and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may also be called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has a function of converting into an electric signal according to the amount of light from the scintillator, and has, for example, an optical sensor such as a photomultiplier tube (PMT).

The X-ray detector 33 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electric signal.

The X-ray data acquisition circuit (DAS (Data Acquisition System)) 34 is an amplifier that amplifies the electric signal output from each X-ray detection element of the X-ray detector 33, and an analog-to-digital conversion of the electric signal (DAS). It has an A / D converter for AD conversion) and generates detection data. The X-ray data acquisition circuit 34 is a conversion board composed of a plurality of signal processing boards (hereinafter referred to as AD conversion boards) including signal processing circuits such as an IV converter and an AD converter that receive data from an X-ray detection element. Have a group. The detection data generated by the X-ray data acquisition circuit 34 is transferred to the console 50.

The rotating pedestal of the X-ray CT pedestal 31 rotates around the same rotation axis as the rotating pedestal of the SPECT pedestal 21. The rotating pedestal of the X-ray CT pedestal 31 is an annular frame that supports the X-ray tube 32 and the X-ray detector 33 so as to face each other and rotates the X-ray tube 32 and the X-ray detector 33 around the z-axis. is there. In addition to the X-ray tube 32 and the X-ray detector 33, the rotary gantry further supports a high-voltage device and an X-ray data acquisition circuit 34. The detection data generated by the X-ray data acquisition circuit 34 is a photodiode provided on the fixed frame of the X-ray CT frame 31 by optical communication from a transmitter having a light emitting diode (LED) provided on the rotary frame. Is transmitted to a receiver having a diode and is transferred to the console 50. The method of transmitting the detection data from the rotating pedestal of the X-ray CT pedestal 31 to the fixed pedestal is not limited to optical communication, and any method may be adopted as long as it is a non-contact type data transmission.

The sleeper device 40 is a device for placing and moving a subject to be scanned, and includes a top plate 41, a base, a sleeper drive device, and a support frame.

The base is a housing that supports the support frame so as to be movable in the vertical direction (y direction). The sleeper drive device is a motor or actuator that moves the top plate 41 on which the subject is placed in the long axis direction (z direction) of the top plate 41. The top plate 41 provided on the upper surface of the support frame is a plate on which the subject is placed.

In addition to the top plate 41, the sleeper drive device may move the support frame in the long axis direction (z direction) of the top plate 41. Further, the sleeper drive device may be moved together with the base of the sleeper device 40.

The console 50 is composed of, for example, a general personal computer or a workstation, and has an input interface 51, a display 52, a storage circuit 53, a network connection circuit 54, and a processing circuit 55. The console 50 does not have to be provided independently. For example, a part of the configuration 51-55 of the console 50 is dispersed on the front surface or side surface of the SPECT pedestal 21 or the front surface or side surface of the X-ray CT pedestal 31. It may be provided.

The input interface 51 is composed of general input devices such as a trackball, a switch button, a mouse, a keyboard, and a numeric keypad, and outputs an operation input signal corresponding to the user's operation to the processing circuit 55. For example, the user can specify the imaging target site and the RI to be used in the inspection via the input interface 51.

The display 52 is composed of a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display.

The storage circuit 53 has a configuration including a recording medium that can be read by a processor, such as a magnetic or optical recording medium or a semiconductor memory. Some or all of the programs and data in these recording media may be configured to be downloaded by communication over an electronic network.

The network connection circuit 54 is composed of, for example, a network card having a predetermined printed circuit board, and implements various information communication protocols according to the form of the network. The network connection circuit 54 connects the nuclear medicine diagnostic apparatus 1 and other devices according to the various protocols. An electrical connection or the like via an electronic network can be applied to this connection. Here, the electronic network means a general information communication network using telecommunications technology, and in addition to a wireless / wired hospital backbone LAN (Local Area Network) and an Internet network, a telephone communication network, an optical fiber communication network, and a cable. Includes communication networks and satellite communication networks.

The processing circuit 55 is a processor that reads and executes a program stored in the storage circuit 53 to execute a process for performing a start-up inspection of the gamma ray detector 23 without using RI.

As shown in FIG. 2, the processor of the processing circuit 55 realizes the inspection imaging control function 551, the image generation function 552, and the rotation control function 553. Each of these functions is stored in the storage circuit 53 in the form of a program.

The inspection image pickup control function 551 controls the gamma ray scanner device 20 and the X-ray scanner device 30 to generate an image for inspection (daily inspection performed at the start of work) of the SPECT-CT device 10 (daily inspection). (Hereinafter referred to as inspection imaging) is executed.

The image generation function 552 generates image data based on the output of the gamma ray detector 23 that detects the X-rays emitted from the X-ray tube 32. For example, when inspection imaging is performed, the image generation function 552 generates image data for inspection of the gamma ray detector 23 based on the output of the gamma ray detector 23 that detects the X-rays emitted from the X-ray tube 32. , A SPECT image for inspection of the gamma ray detector 23 (hereinafter referred to as an inspection SPECT image) is generated based on this image data and displayed on the display 52. The image generation function 552 is an example of a generation unit.

The inspection SPECT image is at least an image for determining the presence or absence of abnormal accumulation of the gamma ray detector 23, an image for determining the presence or absence of defects, an image for determining uniformity, and an image for shifting the center of rotation of the gamma ray detector 23. Includes one image.

In the confirmation of abnormal accumulation and defect, it is confirmed whether there is a place where the count is overestimated or a place where the count is not entered at all among the PMTs of the gamma ray detector 23. In the confirmation of uniformity, it is confirmed whether the irradiated radiation can be uniformly detected on the detection surface of the gamma ray detector 23, and whether there is unevenness or an unintended decrease in brightness. For example, if the gamma ray detector 23 sags or bends during rotation, the uniformity is lost.

By checking the inspection SPECT image generated based on the X-rays emitted from the X-ray tube 32 without using the inspection RI, the user can check the abnormal accumulation of the gamma ray detector, the presence or absence of defects, and the uniformity. The gamma ray detector 23 can be inspected at the start by visually observing the characteristics and the deviation of the rotation center.

Further, the image generation function 552 may analyze the inspection SPECT image captured this time, and when an abnormality is detected, display an image to that effect on the display 52.

The rotation control function 553 is controlled by the inspection imaging control function 551 at the time of inspection imaging for confirming the rotation center deviation, and the X-ray tube 32 and the gamma ray detector 23 are on xy in-plane coordinates orthogonal to the rotation axis. The rotation of the X-ray tube 32 and the rotation of the gamma ray detector 23 are synchronized so as to face each other. This rotation synchronization will be described later with reference to FIG.

FIG. 3 is an explanatory diagram showing an example of a case where the X-ray detector 33 detects the X-rays emitted from the X-ray tube 32.

As shown in FIG. 3, normally, the irradiation range of the X-rays emitted from the X-ray tube 32 is defined so as to irradiate the X-ray detector 33 with the X-ray movable diaphragm 32a. At this time, the direct X-ray bundle 61 irradiates the X-ray detector 33 and does not irradiate the gamma ray detector 23.

On the other hand, when the direct X-ray bundle 61 irradiates the X-ray detector 33, the scattered X-rays are considered to irradiate the gamma ray detector 23.

Therefore, the SPECT-CT apparatus 10 according to the present embodiment generates an inspection image by using X-rays emitted from the X-ray tube 32 without using RI at the time of inspection and imaging.

FIG. 4 is an explanatory diagram showing an example of the first method of inspection imaging according to the present embodiment. The first method of inspection imaging is a method of performing inspection imaging using scattered X-rays. As shown in FIG. 4, when the direct X-ray bundle 61 irradiates the X-ray detector 33, the scattered X-ray bundle 62 irradiates the gamma ray detector 23.

The inspection imaging control function 551 causes the X-ray detector 33 to directly irradiate the X-ray detector 33 from the X-ray tube 32 via the X-ray movable diaphragm 32a in the first method of inspection imaging. At this time, the gamma ray detector 23 detects scattered X-rays emitted from the X-ray tube 32. Further, the image generation function 552 generates image data for inspection based on the output of the gamma ray detector 23 based on scattered rays, and generates a SPECT image for inspection of the gamma ray detector 23 based on the image data for inspection. Then, it is displayed on the display 52.

FIG. 5A is an explanatory diagram showing an example of the second method of inspection imaging according to the present embodiment, and FIG. 5B is an explanation showing another example of the second method of inspection imaging according to the present embodiment. It is a figure.

The second method of inspection imaging is a method of performing inspection imaging using direct X-rays.

The inspection imaging control function 551 causes the gamma ray detector 23 to directly irradiate the gamma ray detector 23 from the X-ray tube 32 via the X-ray movable diaphragm 32a in the second method of inspection imaging. At this time, the gamma ray detector 23 detects the direct X-rays emitted from the X-ray tube 32.

When the intensity of the direct X-rays emitted from the X-ray tube 32 is too strong for the gamma ray detector 23, it is preferable to use a filter for attenuating the intensity. For example, the radiation source side filter 35 may be provided in the vicinity of the X-ray movable diaphragm 32a, and the radiation source side filter 35 may be moved to attenuate the intensity of the direct line from the X-ray tube 32 to the gamma ray detector 23 (FIG. 5). See (a)).

Further, the detector-side filter 25 may be provided in the vicinity of the gamma-ray detector 23, and the intensity of the direct line from the X-ray tube 32 to the gamma-ray detector 23 may be attenuated by the detector-side filter 25 (FIG. 5B). reference). The detector-side filter 25 may be provided on or near the front surface of the collimator 22 (see FIG. 5B), or may be installed on the front surface of the gamma ray detector 23 instead of the collimator 22.

Further, the radiation source side filter 35 and the detector side filter 25 may be used together. The source side filter 35 and the detector side filter 25 are formed by processing a material that attenuates X-rays, such as aluminum.

In the second method of inspection imaging, the image generation function 552 generates inspection image data based on the output of the gamma ray detector 23 based on the direct line, and the gamma ray detector 23 is based on the inspection image data. A SPECT image for inspection is generated and displayed on the display 52.

FIG. 6 is an explanatory diagram showing an example of an inspection SPECT image. Of the detection surfaces of the gamma ray detector 23, the position closer to the X-ray CT pedestal 31 and closer to the X-ray tube 32 has a higher X-ray energy than the position farther from the X-ray CT pedestal 31. FIG. 6 shows an example in which an inspection SPECT image is generated so that the higher the energy, the darker the color.

In advance, the geometric conditions and X-ray conditions of the X-ray tube 32, the X-ray movable aperture 32a, the gamma ray detector 23, etc. at the time of inspection and imaging, and the inspection SPECT image (reference image) under these geometric conditions. , The RI_SPECT image obtained by the inspection imaging using the conventional RI may be associated and stored in the storage circuit 53. In this case, the image generation function 552 simultaneously displays the inspection SPECT image captured this time and the reference image associated with the same geometrical conditions and X-ray conditions as the imaging by displaying them in parallel on the display 52. Can be made to.

FIG. 7A is an explanatory diagram showing a first modification of the first method and the second method of inspection imaging, and FIG. 7B is a second modification of the first method and the second modification of the inspection imaging. It is explanatory drawing which shows an example.

In the first method and the second method of inspection imaging shown in FIGS. 4 and 5, respectively, as shown in FIG. 6, the position of the detection surface of the gamma ray detector 23 is closer to the X-ray CT mount 31. There is a large difference in the energy of X-rays emitted from a distant position. Therefore, regardless of whether the first method of inspection imaging using scattered rays or the second method of inspection imaging using direct rays is used, the gamma ray detector 23 and the collimator 22 are rotated as one. A collimator 22 directed toward the X-ray tube 32 (see FIG. 7 (a)) or directed to the X-ray tube 32 (FIG. 7 (b)), and the emitted X-rays in the detection surface of the gamma ray detector 23 The difference in energy may be reduced.

In the first method of inspection imaging shown in FIG. 4, scattered X-rays attenuated by the collimator 22 irradiate the gamma ray detector 23. In this case, the detected peak will not be a sharp peak, but a peak with a certain width will be detected, but the window width and window level are set to detect X-rays with such a broad width. If it is set, it can be detected without any problem. Further, as long as the inspection SPECT image is generated in the start-up inspection, it does not have to be an X-ray having a sharp peak. Moreover, it can be said that various inspections can be supported by detecting a wide band.

On the other hand, when the first modification or the second modification shown in FIGS. 7A and 7B is applied to the second method of inspection imaging using a direct line, the radiation source side filter 35 and the detector side Direct X-rays with relatively sharp peaks illuminate the gamma ray detector 23, even if attenuated to at least one of the filters 25. In this case, for example, by setting the window width and the window level in detail according to the inspection site of the subject of the next actual SPECT imaging, it is possible to also serve as a preliminary confirmation of the actual SPECT imaging.

FIG. 8 is a diagram for explaining inspection imaging for confirming the rotation center deviation.

The rotation control function 553 is controlled by the inspection imaging control function 551 to rotate the X-ray tube 32 and gamma rays so that the X-ray tube 32 and the gamma ray detector 23 face each other on the xy in-plane coordinates orthogonal to the rotation axis. Synchronize the rotation of the detector 23. The image generation function 552 generates image data based on the X-rays detected by the gamma ray detector 23 during the synchronous rotation of the X-ray tube 32 and the gamma ray detector 23. At this time, the first method of inspection imaging may be used, or the second method may be used. Further, the first modified example or the second modified example illustrated in FIG. 7 may be used.

The inspection imaging control function 551 performs inspection imaging by facing the X-ray tube 32 and the gamma ray detector 23 and rotating the gamma ray detector 23 synchronously for each condition that causes sagging or bending. The image generation function 552 obtains data for correcting the deviation of the center of rotation based on the image data obtained for each condition, generates an image showing the data, and displays it on the display 52. As a condition that causes the gamma ray detector 23 to sag or bend, for example, a rotation speed or the like can be mentioned. Further, when confirming the sagging or bending of the gamma ray detector 23, it is preferable to take a still image at predetermined angles.

Next, an example of the operation of the SPECT-CT apparatus 10 according to the present embodiment will be described.

FIG. 9 is a flowchart showing an example of a procedure for performing a start-up inspection of the gamma ray detector 23 by the SPECT-CT apparatus 10 according to the present embodiment without using RI. In FIG. 9, reference numerals with numbers attached to S indicate each step of the flowchart.

First, in step S1, the inspection imaging control function 551 irradiates X-rays from the X-ray tube 32. Next, in step S2, the gamma ray detector 23 detects the X-rays emitted from the X-ray tube 32.

Next, in step S3, the image generation function 552 generates image data based on the output of the gamma ray detector 23 based on X-rays. Then, in step S4, the image generation function 552 generates an inspection image (inspection SPECT image) of the gamma ray detector 23 based on the image data and displays it on the display 52.

By the above procedure, the start-up inspection of the gamma ray detector 23 can be performed without using RI.

The gamma ray detector 23 of the SPECT-CT apparatus 10 according to the present embodiment detects scattered or direct X-rays emitted from the X-ray tube 32 of the X-ray scanner apparatus 30, and an image based on the detected X-rays. Data can be generated.

Therefore, at the time of the start-up inspection, the gamma ray detector 23 can detect X-rays without using RI. Therefore, the technician is extremely safe without being exposed to RI at each start-up inspection. In addition, the technician does not need to be present to install a radiation source for the start-up inspection every time the start-up inspection is performed, which reduces the burden. In addition, since X-rays can be imaged in a significantly shorter time than RI, which takes time to image, the time required for the start-up inspection can be significantly shortened. Moreover, since it is not necessary to purchase an RI for the start-up inspection, the cost for the start-up inspection can be reduced.

Further, by comparing the image data based on the X-rays detected by the gamma ray detector 23 with time, it becomes possible to detect the abnormality of the X-ray tube 32.

According to at least one embodiment described above, the start-up inspection of the gamma ray detector 23 can be performed without using RI.

In the above embodiment, the term "processor" refers to, for example, a dedicated or general-purpose CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC). It is intended to mean a circuit such as a programmable logic device (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and an FPGA). The processor realizes various functions by reading and executing a program stored in a storage medium.

Further, in the above embodiment, an example in which a single processor of the processing circuit realizes each function is shown, but a processing circuit is formed by combining a plurality of independent processors, and each processor realizes each function. May be good. When a plurality of processors are provided, the storage medium for storing the program may be provided individually for each processor, or one storage medium collectively stores the programs corresponding to the functions of all the processors. May be good.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof.

1 Nuclear medicine diagnostic device 10 SPECT-CT device 11 X-ray tube 20 Gamma ray scanner device 21 SPECT mount 22 Collimeter 23 Gamma ray detector 25 Detector side filter 30 X-ray scanner device 31 X-ray CT mount 32 X-ray tube 32a X Line movable aperture 33 X-ray detector 35 Source side filter 50 Console 55 Processing circuit 61 Direct line bundle 62 Scattered line bundle 551 Inspection imaging control function 552 Image generation function 553 Rotation control function

Claims (10)

An X-ray tube that irradiates X-rays and
An X-ray detector that detects the X-rays emitted from the X-ray tube, and
A gamma ray detector that detects gamma rays emitted from a radiation source administered to a subject,
A generation unit that generates image data by detecting the X-rays emitted from the X-ray tube with the gamma ray detector, and
Medical diagnostic imaging equipment equipped with. The gamma ray detector
The scattered rays of the X-rays emitted from the X-ray tube are detected, and
The generator
The image data is generated based on the output of the gamma ray detector based on the scattered radiation.
The medical diagnostic imaging apparatus according to claim 1. An X-ray diaphragm that directs the X-rays emitted from the X-ray tube toward the gamma ray detector,
With more
The gamma ray detector
The direct line of the X-ray emitted from the X-ray tube is detected,
The generator
The image data is generated based on the output of the gamma ray detector based on the direct line.
The medical diagnostic imaging apparatus according to claim 1. A source-side filter provided near the X-ray diaphragm to attenuate the intensity of the direct line from the X-ray tube to the gamma ray detector.
The medical diagnostic imaging apparatus according to claim 3, further comprising. A detector-side filter provided in the vicinity of the gamma-ray detector to attenuate the intensity of the direct line from the X-ray tube to the gamma-ray detector.
The medical image diagnostic apparatus according to claim 3 or 4, further comprising. The detector side filter is
Attached to the front of the collimator attached to the front of the gamma ray detector,
The medical diagnostic imaging apparatus according to claim 5. The X-ray tube and the gamma ray detector rotate around the same axis of rotation,
A rotation control unit that synchronizes the rotation of the X-ray tube and the rotation of the gamma ray detector so that the X-ray tube and the gamma ray detector face each other on the in-plane coordinates orthogonal to the rotation axis.
With more
The generator
The image data is generated based on the X-rays detected by the gamma-ray detector during the synchronous rotation of the X-ray tube and the gamma-ray detector.
The medical diagnostic imaging apparatus according to any one of claims 1 to 6. The generator
An image for inspection of the gamma ray detector is generated based on the image data.
The medical diagnostic imaging apparatus according to any one of claims 1 to 7. The image for inspection of the gamma ray detector is
An image for determining the presence or absence of abnormal accumulation of the gamma ray detector, an image for determining the presence or absence of defects, an image for determining uniformity, and an image for shifting the center of rotation include at least one image.
The medical diagnostic imaging apparatus according to claim 8. It is an inspection image generation method that generates an inspection image of a gamma ray detector that detects gamma rays emitted from a radiation source administered to a subject.
The step of detecting the X-rays emitted from the X-ray tube by the gamma ray detector, and
A step of generating image data for inspection of the gamma ray detector based on the output of the gamma ray detector based on the X-ray, and
An inspection image generation method having.