JP2013122388A - Radiographic imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiographic imaging apparatus capable of quickly identifying a position, intensity, and type of a radiation source, and instantly determining the soundness of the apparatus.SOLUTION: A radiographic imaging apparatus includes; a gamma camera having a sensor for measuring radiation and a pinhole collimator located in front of the sensor for restricting the incident direction of the radiation; an optical camera for capturing optical images; and a range finder. The apparatus is also equipped with display control means for displaying a radiographic image 60, which is a radiographic image produced from the measurement data of the gamma camera superimposed on an optical image captured by the optical camera, and an energy spectrum 70 from radiation data measured by the sensor on an image display device, which enables quickly identifying a position, intensity, and type of a radiation source and determining the soundness of the sensor from the energy spectrum 70.

Description

  The present invention relates to a radiation imaging apparatus that captures an outdoor or indoor radiation image.

  A portable gamma camera used to capture an outdoor or indoor radiographic image includes a radiation detector that can detect a spatial position and a collimator that limits the incident direction of the radiation to the detector. A pinhole collimator is generally used as the collimator, but a coded aperture collimator or the like may be used to increase sensitivity. In addition, the radiation detector is covered with a shielding material for the purpose of shielding radiation from outside the region of interest, but the shielding material is made of lead, etc., so the radiation detector is small in order to avoid an increase in the weight of the device. It is necessary to make it.

  As the radiation detector, a scintillator, a semiconductor detector, or the like is used. In particular, the semiconductor detector can be easily made into pixels and can have a high spatial resolution, and can be easily miniaturized, thereby reducing the weight of the apparatus. In addition, since the semiconductor detector has high energy resolution, it is also effective for nuclide analysis.

  Although the spatial distribution of radiation can be imaged by using a gamma camera, it is not possible to identify the position of the actual radiation source by itself, so optical imaging that matches the optical axis and viewing angle with the gamma camera A method is used that includes a camera and displays a combined image obtained by superimposing a radiographic image representing a spatial distribution of radiation on an optical image.

  The energy spectrum is a histogram of the measured radiation energy distribution with a predetermined energy width, and is precisely measured by a multi-channel analyzer or the like (for example, Patent Document 1). In a medical gamma camera, correction processing of sensitivity and gain of a detector is performed using this energy spectrum (for example, Patent Document 2).

JP 2008-111704 A JP-T-2004-522164

  The measurement needs of radiation measurement with a portable gamma camera is to identify what and where the source is, in other words, it is possible to identify the source position, source intensity, and nuclide. Desired. As one application destination of the portable gamma camera, a high radiation dose field such as a specific area in a nuclear power plant is assumed. In measurement work in a high dose field, operation in a short time is strongly desired from the viewpoint of reducing exposure dose. Therefore, it is required that the source can be specified in the shortest possible time even in the measurement work with the gamma camera.

  In addition, when using a gamma camera in a high-dose field, it is essential to enhance the shielding of the detector part to reduce background noise. However, other electronic circuit systems and optical cameras are also used to reduce irradiation damage. Shielding is required. However, in a portable gamma camera, there is a limit in weight due to restrictions on the handling properties of the apparatus, so that sufficient shielding is not always performed for electronic circuit systems, optical cameras, and the like. Therefore, system design and operation on the premise of component failure due to irradiation damage are required. The equipment uses parts with high radiation resistance as much as possible. However, parts that are difficult to deal with need to have a structure that can be easily exchanged and that parts must be periodically replaced. In addition, since the risk of device failure is high during actual work, it is necessary to constantly monitor the soundness of the device.

  Therefore, an object of the present invention is to provide a radiation imaging apparatus that can identify the position, intensity, and type of a radiation source in a short time, and that can instantaneously determine the soundness of the apparatus.

  In order to solve the above-described problem, a radiation imaging apparatus according to the present invention includes a detector that measures radiation flying from an imaging target, a collimator that is disposed in front of the detector and restricts the incident direction of the radiation. A radiation imaging apparatus comprising: a gamma camera including: an optical camera that captures an optical image within a field of view of the gamma camera; and an image display device, wherein the gamma camera is obtained from measurement data of the detector. A radiation image generating means for generating a radiation image representing a radiation distribution in the field of view, an image synthesizing means for generating a composite image by superimposing the radiation image on an optical image taken by the optical camera, and for each magnitude of energy An energy spectrum image representing the energy spectrum of the radiation source is generated by integrating the number of measurement data over the entire area. And energy spectrum image generating means and the energy spectrum image and the composite image was intended to and a display control means for displaying on the image display device.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation imaging device which can identify the position, intensity | strength, and kind of a radiation source in a short time, and can judge the soundness of an apparatus instantaneously can be provided.

1 is an overall configuration diagram of a radiation imaging apparatus according to an embodiment of the present invention. It is sectional drawing which shows the internal structure of the gamma camera with which a radiation imaging device is provided. It is a perspective view showing an example of a pixel type detector built in a gamma camera. It is a perspective view which shows the 1st modification of a pixel type detector. It is a perspective view which shows the entrance plane side of the 2nd modification of a pixel type detector. It is a perspective view which shows the opposite surface side of the entrance plane of the 2nd modification of a pixel type detector. It is a perspective view which shows the 3rd modification of a pixel type detector. It is a perspective view which shows the scintillator detector which is the 4th modification of a pixel type detector. It is a functional lineblock diagram of a radiation imaging device concerning an embodiment of the present invention. It is a figure which shows the structure and display example of a screen displayed on an image display apparatus. It is a figure which shows the example of a display of a screen when Cs-137 is selected as a nuclide. It is a figure which shows the example of a display of a screen when Cs-134 is selected as a nuclide. It is a figure which shows the example of a display of a screen when the range of the pixel value displayed on a radiographic image is changed.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as appropriate.

<Overall configuration of radiation imaging apparatus>
FIG. 1 is an overall configuration diagram of a radiation imaging apparatus according to the present embodiment. The radiation imaging apparatus 1 includes a gamma camera 10, an optical camera 11, a distance meter 12, a control device 13, and an image display device 14. A radiation image obtained by imaging radiation (gamma rays) incident from a pinhole collimator 30 provided in front of the gamma camera 10 is captured by an optical camera 11 having the same optical axis and viewing angle as that of the gamma camera 10. The control device 13 generates an image that is superimposed on the optical image, which is an image, and causes the image display device 14 to display the image. The distance meter 12 measures the distance to each imaging target existing in the field of view by scanning each region in the field of view of the gamma camera 10, and transmits the measured distance information to the control device 13. This distance information is used by the control device 13 to correct the radiation measurement data input from the gamma camera 10 and calculate the dose rate.

<Gamma camera>
FIG. 2 is a cross-sectional view showing the internal structure of the gamma camera 10 included in the radiation imaging apparatus 1. The gamma camera 10 includes a detector module 20, a pinhole collimator 30, and a shield 40.

  The pinhole collimator 30 is made of, for example, tungsten, and shields the incidence of radiation from outside the field of view, and limits the incident direction of gamma rays incident on the detector 21 in the detector module 20. The shield 40 is made of lead having a thickness of 2 cm, for example, and blocks the incidence of gamma rays from outside the field of view. The material of the pinhole collimator 30 and the shield 40 is not limited to the above, and the material may be appropriately selected according to the measurement environment and intended use for the purpose of shielding gamma rays. Of course, the thickness of the shield 40 is not limited to the above.

<Detector module>
Next, the detector module 20 will be described in detail with reference to FIG. The detector module 20 includes a detector 21, a detector substrate 23, an ASIC (Application Specific Integrated Circuit) substrate 24, an ASIC 25, and a light shielding / electromagnetic shield 26.

  The detector 21 is composed of a semiconductor (for example, CdTe) and an electrode, and is held on the detector substrate 23. The ASIC 25 is an application specific integrated circuit for amplifying a minute signal output when the detector 21 detects a gamma ray, and is mounted on the ASIC substrate 24. A minute detection signal output from the detector 21 is input to the ASIC 25 via the detector substrate 23 and the ASIC substrate 24, amplified, and output. The detection signal amplified by the ASIC 25 is converted into a digital signal by an ADC (Analog to Digital Converter) (not shown), and then a gamma ray is detected by a digital circuit element such as an FPGA (Field Programmable Gate Array) (not shown). Are converted into digital data such as the ID (identification), the peak value of the detection signal, and the detection time, and output to the control device 13 (FIG. 1). These detectors 21 and the like are surrounded by an aluminum light shielding / electromagnetic shield 26 that blocks light and electromagnetic waves incident from the outside.

<Detector>
FIG. 3 is a perspective view showing an example of a pixel-type detector built in the gamma camera 10. In this example, a detector group 21A is configured by two-dimensionally arranging detectors 21 using CdTe semiconductors on a detector substrate 23 (see FIG. 2). Each detector 21 corresponds to one pixel constituting the generated radiation image.

  In FIG. 3, the upper surface side is a gamma ray incident surface 21 f of the detector 21, and electrodes 22 a and 22 b for applying a voltage are arranged on the side surface of the detector 21. Thus, unlike a scintillator made of one large crystal, detection signals are collected in units of detectors 21, that is, in units of pixels.

  Further, the pixel-type detector built in the gamma camera 10 is not limited to the detector group 21A shown in FIG. 3 in which the detector 21 is divided for each pixel, as shown in FIGS. 4 to 8. Detectors (detector groups 21B, 21C, 21D, 21E) may be used.

  FIG. 4 is a perspective view showing a first modification of the pixel-type detector. In the pixel-type detector (detector group 21B) shown in FIG. 4, the common electrode 22c is placed on one surface of the CdTe semiconductor substrate, that is, the entire surface on the incident surface 21f side with respect to one CdTe semiconductor substrate. The electrode 22d divided in pixel units is arranged on the surface opposite to the incident surface 21f, and the CdTe semiconductor substrate and the common electrode 22c in an area corresponding to one electrode 22d are respectively A detector corresponding to a pixel is configured.

  FIG. 5 is a perspective view showing an incident surface side of a second modification of the pixel type detector, and FIG. 6 is a perspective view showing an opposite surface side of the incident surface. The pixel-type detector (detector group 21C) shown in FIGS. 5 and 6 has a common electrode 22c disposed on the entire incident surface 21f side of one CdTe semiconductor substrate, and the CdTe semiconductor substrate. Individual detectors are configured by disposing electrodes 22d divided in units of pixels on the surface opposite to the incident surface 21f, and in addition dividing the semiconductor substrate by grooves formed by dicing.

  FIG. 7 is a perspective view showing a third modification of the pixel-type detector. In the pixel-type detector (detector group 21D) shown in FIG. 7, a plurality of strip-like electrodes 22e and 22f are twisted at right angles to the upper surface and the lower surface of the CdTe semiconductor substrate with respect to one CdTe semiconductor substrate. Are arranged facing each other. The belt-like electrode 22e on either the upper surface or the lower surface is used as an anode, and the belt-like electrode 22f on the other surface is used as a cathode. A portion where the anode electrode 22e and the cathode electrode 22f cross and face each other forms one detector (see Japanese Patent Application Laid-Open No. 2004-125757).

  FIG. 8 is a perspective view showing a scintillator detector which is a fourth modification of the pixel-type detector. In the pixel type detector (detector group 21E) shown in FIG. 8, small scintillator detectors composed of a scintillator 21g and a photodiode 21h are two-dimensionally arranged on a detector substrate 23 (see FIG. 2). In this case, the side surface of each scintillator 21g is surrounded by a light shielding material (not shown). Further, as a modification of the scintillator detector shown in FIG. 8, it may be configured by a scintillator 21g divided for each pixel and a position-sensitive photomultiplier tube (PSPMT).

<Display control>
Next, display control of radiation measurement data in the radiation imaging apparatus 1 will be described. FIG. 9 is a functional configuration diagram of the radiation imaging apparatus 1 according to the present embodiment illustrated in FIG. 1. As shown in FIG. 9, display control of radiation measurement data in the radiation imaging apparatus 1 is performed by a control device 13 (see FIG. 1) configured by a computer, which is measured from a gamma camera 10 that measures radiation flying from an imaging target. Data, optical image data in the field of view of the gamma camera 10 taken by the optical camera 11, and distance data to the imaging target in the field of view of the gamma camera 10 measured by the distance meter 12 are input, and the keyboard In accordance with the measurement conditions and display conditions input from the input device 15, etc., predetermined calculation processing is performed, and a measurement result screen is displayed on the image display device 14 (see FIG. 1) such as a liquid crystal display.

  The control device 13 loads a predetermined program from a storage device (not shown) into a main memory and executes it by a CPU (Central Processing Unit) (not shown), thereby generating an optical image generation means 51, a distance information calculation means 52, and a radiation image generation. The functions of the means 53, the image composition means 54, the energy spectrum image generation means 55, and the display control means 56 are embodied.

  In the radiation imaging apparatus 1 according to the present embodiment, the operator sets necessary measurement conditions and the like using the input device 15 and performs control such as start / end of imaging. Therefore, it is assumed that the input device 15 is provided with a measurement condition input button, an imaging start button, an imaging end button, and a state display function (lamp or liquid crystal panel) such as the temperature of the device, which are not shown. These buttons and display functions can be mounted on the screen of the image display device 14 by a program executed by the control device 13.

  The optical image generation unit 51 generates bitmap data of the optical image in the field of view of the gamma camera 10 from the optical image data input from the optical camera 11 and delivers it to the image synthesis unit 54. The distance information calculation unit 52 generates distance information indicating the distance from the distance data input from the distance meter 12 to the imaging target for each region in the field of view of the gamma camera 10 and delivers it to the radiation image generation unit 53.

  The radiation image generation means 53 acquires radiation measurement data including the detector ID input from the gamma camera 10 and the peak value (energy) of the detection signal, and calculates the number of radiation measurement data for each detector 21 (for each pixel). By counting, a gamma ray count number and a count rate (count / sec) are calculated, and bitmap data of a radiographic image indicating the radiation dose for each pixel is generated and delivered to the image synthesis means 54. The radiation image generation means 53 corrects each radiation measurement data for each pixel by the distance to the imaging target in the area corresponding to the pixel delivered from the distance information calculation means 52 and converts the radiation into the dose rate. It is also possible to generate image bitmap data.

  Here, the bitmap data of the generated radiographic image is the intensity of the above-mentioned gamma ray count number, count rate, dose rate, etc., as illustrated in the radiographic image 60 of FIG. This is the data that is the source of the image that displays. In the present embodiment, it is assumed that the display is switched to any one of the gamma ray count number, the count rate, and the dose rate by operating a button (not shown).

  The image synthesizing unit 54 synthesizes (overlays) the radiographic image bitmap data delivered from the radiographic image generating unit 53 with the bitmap data of the optical image delivered from the optical image generating unit 51 as a background. Thus, bitmap data of the radiation image 60 (FIG. 10) to be displayed on the image display device 14 is generated and delivered to the display control means 56. At this time, it is preferable that the image synthesizing unit 54 adjusts the shading and color tone of the radiation bitmap image so that the display is easy to see according to the shading and tone of the optical image to be synthesized as the background. In addition, in the radiographic image 60 of FIGS. 10-13, the drawing of the background optical image is abbreviate | omitted for simplification.

  The energy spectrum image generation means 55 classifies the radiation measurement data input from the gamma camera 10 according to the magnitude of the crest value (energy), and integrates the number of measurement data for each energy magnitude over the entire region. Energy spectrum image data is generated and delivered to the display control means 56.

  The display control unit 56 includes the bitmap data of the radiation image delivered from the image synthesis unit 54 and the energy spectrum image delivered from the energy spectrum image generation unit 55 according to the measurement condition and the display condition input from the input device 15. The screen data of the measurement result to be displayed on the image display device 14 is generated by performing necessary editing on the data. The generated screen data of the measurement result is written in a video memory (not shown) and displayed on the image display device 14.

<Screen configuration and data example>
Next, the configuration of screens and data examples displayed on the image display device 14 of the radiation imaging apparatus 1 of the present embodiment will be described with reference to FIGS. As shown in FIG. 10, a radiation image 60, an energy spectrum 70, a nuclide selection button 80, a display pixel value change slider 90, and an integration time selection button 100 are arranged on the screen.

  The radiographic image 60 is displayed by superimposing the optical image on the radiographic image by the image synthesizing unit 54 and performing the necessary editing by the display control unit 56. In the energy spectrum 70, an energy spectrum image generated by the energy spectrum image generating unit 55 and subjected to necessary editing by the display control unit 56 is displayed.

  The nuclide selection button 80 is an operation button for setting an energy range corresponding to the photopeak of the nuclide, and includes, for example, a general button 81, a Cs-137 button 82, and a Cs-134 button 83. When any of these operation buttons is selected, an energy window preset according to the nuclide photo peak is displayed and included in the energy window as shown by shading on the energy spectrum 70. A radiation image 60 generated from the measurement data is displayed.

  The upper limit value setting bar 91 and the lower limit value setting bar 92 constituting the display pixel value change slider 90 are moved in the vertical direction using a mouse or the like, respectively, so that the upper limit of the radiation bitmap image displayed on the radiation image 60 is displayed. The range of the pixel value and the lower limit pixel value is set. The radiation image 60 displays the gamma ray count number, count rate, or dose rate of each pixel in color or shade display, and by limiting the range of pixel values to be displayed using the display pixel value change slider 90, The scale of the pixel value range to be viewed can be enlarged and highlighted. Specifically, the pixel value of each pixel equal to or higher than the upper limit pixel value corresponding to the slide position of the upper limit value setting bar 91 is set as the maximum pixel value, and each pixel equal to or lower than the lower limit pixel value corresponding to the slide position of the lower limit value setting bar 92 The pixel value of each pixel is changed so that the pixel value between the lower limit pixel value and the upper limit pixel value is linearly mapped between the minimum pixel value and the maximum pixel value.

  The integration time selection button 100 is composed of a plurality of radio buttons (selection operation buttons) for setting the integration time for radiation measurement. For example, as shown in FIG. If there is, the measurement data for the last 10 seconds are integrated, and the radiation image 60 and the energy spectrum 70 are displayed. In a low-dose field, it is necessary to reduce the statistical error by collecting measurement data by setting a longer integration time. On the contrary, since the counting rate is high in a high dose field, the integration time may be set short and measurement may be performed in a short time. Incidentally, in the radiation imaging apparatus 1 of this embodiment, the image of the radiation image 60 and the energy spectrum 70 is updated at intervals of 1 second. Of course, the image update time is not limited to 1 second, and may be set as appropriate according to the use environment.

  In FIG. 10, the general button 81 is selected from the nuclide selection buttons 80, and the display pixel value change slider 90 displays the upper limit value setting bar 91 at the top and the lower limit value setting bar 92 at the bottom. It is a display example of a screen when the range of pixel values is set to the maximum and the integration time is set to 10 seconds by the integration time selection button 100. In this case, the radiation image 60 and the energy spectrum 70 obtained by integrating the measurement data for the last 10 seconds are displayed, and the energy window is displayed on the energy spectrum 70 so as to include all the measurement data (gamma ray count) having energy equal to or higher than a predetermined value. Is set, and a radiation image 60 generated from the measurement data is displayed.

  FIG. 11 is a display example of the screen when the Cs-137 button 82 is selected from the nuclide selection buttons 80 for the same measurement data as in FIG. 10, and the photopeak energy of Cs-137 is displayed on the energy spectrum 70. The energy window is set in a range of 5% before and after 662 keV (0.662 MeV). Accordingly, the radiation image 60 generated from the measurement data included in the energy window is displayed, so that the radiation source position of Cs-137 can be specified.

  FIG. 12 is a display example of the screen when the Cs-134 button 83 is similarly selected from the nuclide selection buttons 80. On the energy spectrum 70, 605 keV (0. 605 MeV) and 796 keV (0.796 MeV), the energy window is set in the range of 5% before and after. Along with this, the radiation image 60 generated from the measurement data included in the energy window is displayed, so that the position of the Cs-134 radiation source can be specified.

  Of course, the nuclide setting is not limited to this, and other nuclides may be set according to the measurement target, or the upper and lower limits of the energy window may be manually input. Further, the window width is not limited to 5%, and may be set as appropriate according to the energy resolution of the detector 21 and the like.

  FIG. 13 shows radiation measurement data to be displayed as a result of the operator sliding the upper limit value setting bar 91 of the display pixel value change slider 90 downward in the state of FIG. 11 in which Cs-137 is selected as the nuclide. This is a display example when the upper limit pixel value of the gamma ray count number, the count rate, or the dose rate is set to about 50% of the maximum pixel value. In the radiographic image 60 of FIG. 11, only a portion having a relatively high intensity was visible. However, in the radiographic image 60 of FIG. 13, the pixel value of the portion having the small pixel value in FIG. Since the pixel value of the portion with the larger value is scaled up to the maximum pixel value, the portion with the relatively lower intensity can be seen, and the line source having the lower intensity than the line source visible in FIG. It can be seen that there is also an upward direction.

  As described above, according to the present embodiment, the position of the radiation source and the nuclide can be identified in a short time from the radiation image 60 combined with the optical image, and the measurement data is measured according to the distance from the imaging target. By correcting the above, the intensity distribution of the radiation source can be grasped almost in real time. In measurement in a high-dose field where the radiation source distribution is unknown, the merit of being able to grasp the intensity distribution for each nuclide in a short time is very large from the viewpoint of reducing the exposure dose. If the nuclide can be identified, the response method can be changed on the spot from the viewpoint of reducing the exposure dose. For example, if the energy of gamma rays is low, it can be judged that shielding of thin lead is sufficient, but conversely, if the energy is high, thick shielding is necessary. Further, at the time of decontamination work, more effective decontamination work can be performed by changing the decontamination method for each nuclide.

  Moreover, the health of the apparatus can be checked by displaying the energy spectrum 70. When the gamma camera 10 completely fails and there is no output, no spectrum is displayed at all, so it is immediately known that there is a failure. If an abnormality occurs in the detector 21 and noise is output, the peak value becomes inaccurate and the photo peak cannot be measured. Therefore, the occurrence of a failure of the detector 21 can be detected. Accordingly, by checking the displayed energy spectrum 70, it is possible to check the soundness of the apparatus in almost real time.

  Further, the integration time selection button 100 can set and measure the integration time according to the dose. Particularly in a high-dose field, short-time work is desired from the viewpoint of reducing exposure, and the effect of enabling measurement in a shorter time is great. It is very effective even in situations that change from moment to moment, and it is possible to deal with decontamination work and emergency situations. Further, it is possible to perform imaging while moving instead of fixed imaging.

  In addition, since the display scale of the pixel values of the radiation image 60 can be changed by the display pixel value change slider 90, it is possible to emphasize and display the intensity portion desired to be viewed. For example, it is possible to identify a hot spot having the second intensity that is hidden behind the largest hot spot and difficult to discriminate. Further, since the radiation image 60 is displayed so as to be superimposed on the optical image, the lower pixel value portion of the radiation image is made transparent so that the visible light image can be easily seen. Therefore, although the high pixel value portion (high dose portion) is emphasized and its position can be understood well, there is a problem that the distribution of the low pixel value portion (low dose portion) is difficult to understand. According to the present embodiment, the display of the low pixel value portion (low dose portion) that is difficult to discriminate can be clearly displayed by highlighting and displaying the low pixel value pixels by the display pixel value change slider 90. it can.

  In this embodiment, a semiconductor radiation detector is used. The semiconductor detector is characterized in that it can be finely processed and can be miniaturized, and has high energy resolution. High spatial resolution can be realized by miniaturizing a semiconductor element to form a pixel, and by reducing the size, the weight of the shield can be suppressed and the apparatus can be reduced in weight. In addition, the high energy resolution enables nuclide analysis, narrows the energy window, reduces noise such as scattered radiation mixed in the energy window, and reduces the S / N (Signal / Noise) ratio. High measurement is possible. Specifically, a more accurate radiographic image for each nuclide can be provided.

DESCRIPTION OF SYMBOLS 1 Radiation imaging device 10 Gamma camera 11 Optical camera 12 Distance meter 13 Control device 14 Image display device 15 Input device 20 Detector module 21 Detector 21A, 21B, 21C, 21D, 21E Detector group 21f Incident surface 21g Scintillator 21h Photodiode 22a, 22b, 22d, 22c, 22e, 22f Electrode 22c Common electrode 23 Detector board 24 ASIC board 25 ASIC (radiation measurement circuit)
26 light shielding / electromagnetic shield 30 pinhole collimator 40 shield 51 optical image generation means 52 distance information calculation means 53 radiation image generation means 54 image synthesis means 55 energy spectrum image generation means 56 display control means 60 radiation image 70 energy spectrum 80 nuclide selection Button 81 General button 82 Cs-137 button 83 Cs-134 button 90 Display pixel value change slider 91 Upper limit value setting bar 92 Lower limit value setting bar 100 Integration time selection button

Claims (5)

A gamma camera comprising: a detector that measures radiation flying from an imaging target; and a collimator that is disposed in front of the detector to limit the incident direction of the radiation;
An optical camera that captures an optical image within the field of view of the gamma camera;
An image display device;
A radiation imaging apparatus comprising:
A radiation image generating means for generating a radiation image representing a radiation distribution in the field of view of the gamma camera from the measurement data of the detector;
Image composition means for generating a composite image by superimposing the radiation image on an optical image captured by the optical camera;
Energy spectrum image generating means for generating an energy spectrum image representing an energy spectrum of the radiation source by integrating the number of measurement data for all areas for each energy magnitude;
Display control means for displaying the composite image and the energy spectrum image on the image display device;
A radiation imaging apparatus comprising: The radiation imaging apparatus according to claim 1,
The display control means includes
Displaying a predetermined energy window set in advance corresponding to the nuclide on the energy spectrum image, and causing the radiation image generation unit to generate a radiation image corresponding to measurement data included in the energy window; A radiation imaging apparatus. The radiation imaging apparatus according to claim 1 or 2,
A radiation imaging apparatus comprising input means for limiting a range of an upper limit pixel value and a lower limit pixel value for changing and displaying a pixel value of each pixel displayed in the radiation image. The radiation imaging apparatus according to any one of claims 1 to 3,
A radiation imaging apparatus comprising input means for changing the predetermined time for measuring the radiation data. The radiation imaging apparatus according to any one of claims 1 to 4,
A radiation imaging apparatus using a pixel-type semiconductor radiation detector as the detector for measuring the radiation.