JP2003279653A - Radiation examination apparatus, and method of detecting radiation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation examination apparatus that facilitates alignment of each image, and is simplified in apparatus constitution, and a method of detecting radiation. <P>SOLUTION: This radiation inspection apparatus 1 is provided with a bed 31 for mounting a subject 4, an imaging device 2 and a radiation inspection controller 10. The imaging device 2 has an X-ray generator 6 for irradiating the subject 4 with an X-ray, means 61, 62 for moving a position of the X-ray generator 6, a plurality of radiation detectors 5 for detecting two kinds of radiations of a γ-ray emitted from the subject 4 and the transmitted X-ray, and a signal processing circuit system provided with at least one out of a circuit 8 for processing a γ-ray detection signal and a circuit for processing an X-ray detection signal to the respective radiation detectors 5, and is constituted so that the radiation inspection controller 10. controls the moving of the X-ray generator 6, the start and finish of the X-ray irradiation by the X-ray generator 6, and a signal processing timing of the first radiation detection signal and a signal processing timing of the second radiation detection signal in the signal processing circuit system. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation inspection apparatus utilizing radiation, particularly X-ray CT, positron emission type C
T (Positron Emission computed Tomograph)
y, hereafter referred to as “PET” and single photon emission type CT (single photon emission computed
Tomography; Single Photon Emission Computed Tomo
The present invention relates to a radiation inspection apparatus and a radiation detection method for simultaneously performing a plurality of types of radiation inspection such as graphy (hereinafter referred to as "SPECT").

[0002]

2. Description of the Related Art An inspection technique utilizing radiation can inspect the inside of a subject nondestructively. In particular, X-ray CT, PET, SPECT and the like are available as radiological inspection techniques for the human body. Each of these techniques is a technique of measuring a physical quantity of a detection target as an integral value in a flight direction of a radiation, and back-projecting the integral value to calculate the physical quantity of each voxel in the subject to form an image. These technologies need to process a huge amount of data, and with the recent rapid development of computer technology, it has become possible to provide high-speed and high-definition images.

The X-ray CT technique is a technique for measuring the intensity of X-rays that have passed through the subject and imaging the morphological information of the subject from the X-ray penetration rate in the body. The subject is irradiated with X-rays from an X-ray source, the intensity of the X-rays that have passed through the body is measured by a detection element arranged on the opposite side of the subject, and the integrated absorption coefficient of the subject is calculated. The distribution of the integrated absorption coefficient is measured by scanning the X-ray and the detection element. From this integrated absorption coefficient, the IEEE Transaction on Nuclear Scienc
e) The filtered back projection method (Filtered Back Proj) described on page 21 of NS-21.
The absorption coefficient of each voxel is obtained using the section method) and the value is converted into a CT value. The radiation source often used for X-ray CT is around 80 keV.

On the other hand, PET and SPECT are X-ray CT
It is a method that can detect functions and metabolism at the level of molecular biology, which cannot be done by other methods, and can provide functional images of the body. PET is a method of administering a radiopharmaceutical labeled with a positron-emitting radionuclide such as ¹⁸ F, ¹⁵ O, and ¹¹ C, measuring its distribution, and imaging it. The drug is fluorodeoxy glucose (2- [F-18] fluoro-2-deoxy-D-glu
cose, ¹⁸ FDG) and the like, which are used to identify the tumor site by utilizing their high accumulation in tumor tissue due to glucose metabolism. The radionuclide taken into the body decays and emits positron (β +). The emitted positron emits a pair of annihilation γ rays having an energy of 511 keV when annihilated by coupling with an electron. Since this annihilation γ-ray pair is radiated in almost opposite directions (180 ± 0.6 °), the annihilation γ-ray pair is simultaneously detected by the detection element arranged so as to surround the subject, and the radiation direction data is accumulated. Then, projection data can be obtained. By backprojecting projection data (using the above-mentioned filtered back projection method or the like), it becomes possible to identify and image a radiation position (accumulation position of radionuclide).

SPECT is a technique in which a radiopharmaceutical labeled with a single photon-emitting nuclide is administered and its distribution is measured and imaged. A single γ-ray having energy of about several hundred keV is emitted from the drug, and this single γ-ray is measured by the detection element. Since the flight direction cannot be identified by measurement of a single γ-ray, in SPECT, a collimator is inserted in front of the detection element and only γ-rays from a specific direction are detected to obtain projection data. Like PET
Image data is obtained by back-projecting projection data by using a filtered back projection method or the like. The difference from PET is that there is no need for simultaneous measurement due to the measurement of a single gamma ray,
The number of detection elements is small, and the like, and the device configuration is simple and the device is relatively inexpensive. On the other hand, SPECT
Uses a collimator, the detection rate of γ rays is low and the image quality is generally poor.

[0006] As described above, PET and SPECT provide functional images by utilizing the metabolism in the body, so that the site where the drug is accumulated can be extracted with good contrast, but there is a problem that the positional relationship with surrounding organs cannot be grasped. is there. Therefore, in recent years, a technique for merging a morphological image such as X-ray CT and a functional image such as PET or SPECT to perform a more advanced diagnosis has attracted attention. As one method of this prior art, Japanese Patent Application Laid-Open No. 7-2024
There is a technique described in Japanese Patent No. 5 publication. In the present technology, the pseudo simultaneous imaging is performed by the PET inspection and the X-ray CT inspection.

In Japanese Patent Laid-Open No. 7-20245, an X-ray C
When the T inspection and the PET inspection are continuously performed, the X-ray CT inspection device 90 and the PET inspection device 80 are arranged as shown in FIG. 14 so that one bed 30 such as a bed can be used in common. Then, the X-ray CT inspection device 90
After performing the inspection in step 1, the subject holding mechanism 30 carries the subject 40 to the PET inspection device 80 and performs the PET inspection. In this case, the time interval between the two tests is short and the subject does not move relatively large, so that the positional relationship between the two data can be known to some extent. Using the positional relationship information, the PET data and the X-ray CT data are combined to specify the lesion position of the subject.

Japanese Unexamined Patent Publication (Kokai) No. 9-5441 describes a radiation inspection apparatus in which an image pickup apparatus of an X-ray CT apparatus and an image pickup apparatus of a SPECT apparatus are arranged in parallel so that the bed also serves as a bed. The X-ray CT data and the SPECT data, which are the imaging data obtained by each imaging device, are combined to specify the lesion position of the subject.

[0009]

In the radiation inspection apparatus described in each of the above-mentioned publications, at first glance it seems that the positional relationship between the two pieces of image data is clear. It may move. The imaging resolution of the recent PET apparatus is about 5 mm, and the resolution of the imaging apparatus of the X-ray CT apparatus is about one digit smaller than that, which is about 0.5 mm. Therefore, if the subject moves between the imaging devices or the angle of the subject changes, the correspondence between the image data obtained by the imaging devices becomes unclear. As a result, for example, after each image data is reconstructed, common characteristic regions existing in each image are extracted, the positional relation of each image is obtained from the positional relation of the characteristic regions, and alignment is performed. There is a problem that it becomes necessary. Further, these radiation inspection apparatuses have another problem that the apparatus configuration is complicated because they are provided with two image pickup apparatuses each having a radiation detector and the like.

Therefore, an object of the present invention is to provide a radiation inspection apparatus and a radiation detection method in which each image can be easily aligned and the apparatus configuration is simplified.

[0011]

In order to achieve the above object, the present invention has a structure in which a plurality of radiation examinations can be performed by one image pickup apparatus. Specifically, the present invention includes a bed on which a subject is placed, an imaging device, a plurality of radiation detection elements are arranged so as to surround the subject, and a plurality of types of signal processing circuits are provided in each of the radiation detection elements, and A configuration in which a plurality of types of radiation inspection can be performed by incorporating an inspection sequence for performing a plurality of radiation inspections and providing a radiation inspection control device that controls switching of the signal processing circuits and operation of the X-ray generator based on the sequences. It is what In the present invention, since the apparatus is composed of one imaging device and a plurality of radiological examinations can be automatically performed based on the above-mentioned examination sequence,
It is extremely easy to combine a plurality of radiation inspection images, and the detection device and the detection method are simplified.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the radiation inspection apparatus of the present invention will be described in detail below as first to fourth embodiments with reference to the drawings. The radiation inspection apparatus described below also executes the radiation detection method of the present invention.

[First Embodiment] A radiation inspection apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 to 6. Figure 1
It is a figure which shows the structure of the radiation inspection apparatus 1 of 1st Embodiment. FIG. 2 is a diagram showing a detailed configuration of the PET signal processing circuit 8. FIG. 3 is a graph showing the amplified γ-ray detection signal (hereinafter referred to as “γ-ray image pickup signal”). FIG. 4 is a graph in which the signal of FIG. 3 is processed by the slow wave forming circuit 82. FIG. 5 is a diagram showing a detailed configuration of the CT signal processing circuit 9. FIG. 6 is a time chart showing a current accumulation state in the circuit 9 of FIG.

As shown in FIG. 1, the radiation inspection apparatus 1 of the present embodiment includes an image pickup apparatus 2, a bed 31, and a bed moving mechanism 3.
2, X-ray generator controller 65, PET signal processing circuit 8,
CT signal processing circuit 9, circuit switching element 71, circuit switching device 72, radiation detector bias power supply 52, CT / PET
It is provided with a control device / image processing device (hereinafter referred to as “CT / PET control device 10”) and a display device 11. CT /
The PET control device 10 corresponds to the "radiation inspection control device" in the claims.

Of these, the image pickup device 2 includes a radiation detector 5,
It has an X-ray generator 6, an X-ray generator body axial direction moving mechanism (hereinafter referred to as "body axis direction moving mechanism 61"), and an X-ray generator circumferential direction moving mechanism (hereinafter referred to as "circumferential direction moving mechanism 62").

(Radiation Detector) The radiation detector 5 shown in FIG. 1 is arranged in an annular shape so as to surround the bed 31 (subject 4), and a hole portion 50 into which the bed 31 is inserted is provided inside the annular shape. It is formed. A large number of radiation detectors 5 are arranged in the axial direction of the hole 50 (hereinafter referred to as “body axis direction”) and in the annular radial direction (about 10,000 in total). The radiation detector 5 is, for example, a semiconductor radiation detector, and has a cubic semiconductor element portion of several mm made of cadmium tellurium (CdTe). The radiation detector is gallium arsenide (Ga).
As) or cadmium tellurium zinc (CZT).

A high voltage is applied to all the radiation detectors 5 by the radiation detector bias power source 52, and the CT / PET controller 1 applies and stops the high voltage.
It is controlled by ON and OFF signals received from 0. The bed 31 can be moved in the body axis direction by the bed moving mechanism 32. When moving the bed 31, the bed moving mechanism 32 uses CT / P.
This is possible by receiving a bed movement amount signal from the ET control device 10 and driving the bed 31 according to the signal.

(X-ray generator) X-ray generator 6 shown in FIG.
Has a known X-ray tube (not shown). This X
The wire tube has a filament hot cathode made of tungsten,
The electrons emitted from the filament are accelerated by applying a voltage (several hundred kV), and the target (M
o, W, etc.). 80 due to the collision of electrons with the anode
X-rays of about keV are generated, and by opening the switch 60 for X-ray emission, the X-rays are emitted from the X-ray generator 6. The X-ray shape is, for example, a fan shape having a spread of 60 ° in the circumferential cross section and 5 ° in the body axis direction. That is, the irradiation is performed in a fan shape having a certain thickness.

The X-ray generator 6 is supported by a body axis direction moving mechanism 61 and is movable in the body axis direction. The X-ray generator 6 moves in the circumferential direction together with the body-axis-direction moving mechanism 61 by moving the circumferential-direction moving mechanism 62 in the circumferential direction by the circumferential-moving rail 64 formed on the X-ray generator holding portion 63. It is also possible to go around. The X-ray generator control device 65 controls the contents of signals received from the CT / PET control device 10 (generation of X-rays, setting of tube voltage and tube current of the X-ray tube, operation of the switch 60, circumferential direction and body axis). The electric power for operating the X-ray generator 6 is supplied according to the movement (in the direction).

(Circuit Switching Element) Each radiation detector 5 shown in FIG. 1 is connected to a circuit switching element 71 by a wiring 51,
It is connected to either the PET signal processing circuit 8 or the CT signal processing circuit 9. For example, numbers (addresses or IDs) are given to all the radiation detectors 5. Circuit switching device 7
2 receives, for example, the number of the radiation detector 5 connected to the CT signal processing circuit 9 from the CT / PET controller 10 and recognizes it, and the radiation detector 5 of the designated number is connected to the CT signal processing circuit 9. The circuit switching element 71 is controlled so that

(PET Signal Processing Circuit) FIG. 2 shows a detailed configuration of the PET signal processing circuit 8. The PET signal circuit 8 is
A pair of γ-rays emitted from the inside of the subject 4 in the direction of 180 ° is measured one by one, and is configured by a so-called pulse counting measurement circuit. The subject 4 has been administered (injected) with a radiopharmaceutical containing ¹⁸ F in advance. One γ ray detected by the radiation detector 5 is γ
It is transmitted to the PET signal processing circuit 8 as a line image pickup signal and is amplified by the preamplification circuit 81. As shown in FIG. 3, the amplified signal has a waveform that first changes rapidly and then decays exponentially. This signal waveform is shaped by the low-speed waveform shaping circuit 82 into a signal having a Gaussian distribution in time as shown in FIG. 4, for example.

Here, the energy of the γ-rays generated in the body by the positron annihilation of the positrons emitted from the radiopharmaceutical for PET is 511 keV as described above. However, not all the γ-ray energy is converted into electric charges inside the semiconductor element (inside the radiation detection element 5). Therefore, in the γ-ray discrimination circuit 83, for example, 450 keV, which is lower than 511 keV, is set as an energy set value, and the signal is made valid only when a signal having an energy equal to or higher than this energy set value is detected. On the other hand, the high-speed waveform shaping circuit 84 detects a steep rise of the signal amplified by the preamplifier 81 and outputs the rise timing as a logic pulse signal. The coincidence counting circuit 85 is also connected to the PET signal processing circuit connected to another radiation detector 5, performs coincidence counting using the pulse signal output from the high-speed waveform shaping circuit 84, and counts the γ-ray imaging signal. (However, it is limited to the γ-rays which are determined to be valid by the γ-ray discrimination circuit 83). The coincidence counting circuit 85 uses the above-mentioned pair of γ
The CT / PET controller 1 converts the two detection points at which the lines have been detected into digitized data as position information for γ-ray detection.
Send to 0. In addition, the PET signal processing circuit 8 is CT / P
Table 1 below shows a format example of data (hereinafter referred to as “γ-ray imaging data”) transmitted to the ET control device 10.

[0023]

[Table 1]

The PET signal processing circuit 8 includes a pair of γ
The circuit configuration is not limited to the above, and a known PET signal processing circuit may be used because it is a circuit for converting the two detection points that have detected the lines into data as position information for γ-ray detection.

(CT signal processing circuit) CT signal processing circuit 9
The detailed configuration of the above is shown in FIG. In the CT signal processing circuit 9,
The X-rays emitted by the X-ray generator 6 described above are detected, and X-rays are detected.
The intensity of the line detection signal (hereinafter referred to as an X-ray image pickup signal) is converted into data. The X-ray emitted from the X-ray generator 6 has a much higher incidence rate than the above-mentioned γ-ray, and is generally composed of a so-called current mode (integration mode) measuring circuit. The radiation detector 5 continuously converts X-rays at a very high rate into electric charges, that is, outputs as electric current.
This current signal is accumulated by the integrating amplifier circuit 91 as shown in FIG. 6, and the peak value of the signal is held by the peak hold circuit 92. The above operation is performed with a reset signal for a fixed period (up to several tens of milliseconds)
The X-ray intensity for every fixed time is converted into data by the peak hold circuit 92 by repeating the above process in the CT / PET controller 1
Sent to 0. In addition, the CT signal processing circuit 9 is a CT / P
Table 2 below shows an example of a format of data transmitted to the ET control device 10 (hereinafter referred to as “X-ray imaging data”).
As shown in Table 2, the position of the X-ray generator 6 at the detection time (address information notified from the X-ray generator control device 65) is added to the X-ray imaging data.

[0026]

[Table 2]

The CT signal processing circuit 9 is a circuit intended to convert the X-ray intensity into data, and the circuit configuration is not specified above, but a known CT signal processing circuit may be used.

(CT / PET controller) CT shown in FIG.
The / PET controller 10 is composed of a dedicated computer or workstation, and inside thereof, creates a timing chart (inspection sequence) for PET examination and CT examination, and based on the timing chart, the bed moving mechanism 32 and X-rays. Generator controller 65, PET
Signal processing circuit 8, CT signal processing circuit 9, circuit switching device 7
2 and the radiation detector bias power supply 52 are instructed to perform a desired operation, and the tomographic image (P
The ET image) and the X-ray signal attenuation rate in each voxel in the subject obtained based on the X-ray imaging data are used to reconstruct the X-ray CT image. Both the reconstructed tomographic images are displayed by the display device 11.

(Operation of Radiation Inspection Apparatus) Next, the operation of the radiation inspection apparatus 1 having the above configuration will be described with reference to FIGS. FIG. 7 is a diagram (timing chart) showing a CT / PET inspection sequence. 8 is shown in FIG.
5 is an example of an information input screen for creating the CT / PET inspection sequence of FIG. FIG. 9 is a diagram for explaining the operation of the CT / PET inspection sequence of FIG.

In the first embodiment, an X-ray CT examination (the act of detecting the X-rays emitted from the X-ray generator 6 and transmitted through the body of the subject 4 by the radiation detector 5) and a PET examination (the subject 4). The act of detecting the γ-ray emitted from the body of the subject 4 by the radiation detector 5 due to the radiopharmaceutical for PET administered to the above) is performed by using one imaging device 2.

Before carrying out the radiological examination, the radiopharmaceutical for PET as described above is first administered to the subject 4 in advance by a method such as injection so that the in-vivo radioactivity becomes 370 MBq. The radiopharmaceutical is selected according to the purpose of examination (recognizing the location of cancer, examination of aneurysm of heart, etc.). The subject 4 waits until the radiopharmaceutical gathers in a state capable of imaging. The radiopharmaceutical gathers in the affected area of the subject 4 after the elapse of the predetermined time. After the predetermined time has passed, the subject 4 is laid on the bed 31. Depending on the type of examination, the radiopharmaceutical may be administered to the subject 4 laid on the bed 31.

The inspector (radiologist or doctor) who performs the CT inspection and the PET inspection needs necessary information (region to obtain a tomographic image (imaging region or region of interest), number of slices, slices) according to the purpose of the inspection. (Interval, CT scan timing, absorbed dose, etc.) are input to the CT / PET controller 10. This may be a method of inputting the data necessary for the information input screen displayed on the display device 11 as shown in FIG. By arranging a combo box, a radio button, or the like on the screen as shown in FIG. 8, input can be performed easily. CT / PET controller 1
At 0, a CT inspection / PET inspection sequence (appropriately abbreviated as “inspection sequence”) is created based on the input information. By the way, "display" of the information input screen of Fig. 8
When the button is clicked, an inspection sequence as shown in FIG. 7 is created inside the CT / PET control device 10 and displayed on the display device 11, and when the “start inspection” button is clicked, the inspection is started. The CT / PET controller 1
At 0, the following parameters are all programmed in a series of test sequences and run at a timing based on the number of clocks relative to the reference time to start the test.

(1) Circulation of the X-ray generator 6, movement in the body axis direction, irradiation amount (tube current, tube voltage), opening / closing of the switch 60 (2) Circuit switching of each radiation detector 5 and radiation detector Application of voltage to bias power source 52 (3) Operation and stop of PET signal processing circuit 8 and CT signal processing circuit 9 (4) Permission and prohibition of transmission of γ-ray imaging data and X-ray imaging data (5) Bed moving mechanism 32 moves

In the first embodiment, about 30 PET inspections are performed, as indicated by PET and CT in the [Inspection] column of FIG.
An inspection sequence is set up in which the CT inspection is performed for each slice about 10 minutes and 20 minutes after the start of the inspection. In this examination sequence, it is assumed that the region of the subject 4 from the chest to the abdomen is mainly imaged. Also,
[H. V. ] Column, the inspection sequence for inserting the operation of once turning the radiation detector bias power supply 52 to zero during the PET inspection is set up (HV; High). Voltage). This is for suppressing the performance deterioration of the radiation detector 5 due to long-term use of the radiation detector 5. Further, as shown in the column of [X-ray generator] in FIG. 7, the X-ray generator 6 is sequenced to operate in response to the CT examination.
In addition, as shown in the [Circuit switching] column in FIG. 7, the radiation detectors 5 are sequenced so as to be switched.

The CT / PET inspection sequence in the first embodiment will be described with reference to FIGS. 7 and 9. In addition,
As described above, since the irradiation area of X-rays spreads in the body axis direction, each radiation detector 5 has a radiation detector group 5i1, 5
Like j1 and 5k1, switching is performed in the body axis direction (depth direction with reference to FIG. 9) as an aggregate of about 10 detectors at the maximum. Supplementally, one radiation detector 5
If the size is 5 mm square, 10 of these will be connected in series (Fig. 9).
When 10 pieces are arranged in series in the depth direction, the total length is 50 mm. The value of 50 mm matches the extent of the spread of X-rays (fan shape having a spread of 5 ° in the body axis direction) in which the irradiation area is spread in the body axis direction.

(Step 10) The subject 4 lying on the bed 31 is moved to a predetermined position. A voltage (several hundreds) is applied to the radiation detector 5 by the radiation detector bias power source 52.
V) is applied, and the total radiation detector 5 is connected to the PET signal processing circuit 8 by the circuit switching device 72. The number of steps in the 20th generation in FIG. 7 is that of the fourth embodiment.

(Step 11) The PET signal processing circuit 8 operates according to an instruction from the CT / PET controller 10,
Start PET inspection. The γ-rays emitted from the body of the subject 4 are detected by the radiation detector 5 and transmitted to the PET signal processing circuit 8 as γ-ray imaging data. PET
The signal processing circuit 8 generates the γ-ray imaging data (see Table 1) as described above, and the CT / PET controller 1
Send to 0. According to the sequence, the PET inspection is performed for a while in this state.

(Step 12) Next, the radiation detector bias power source 52 is set to 0 V to stop the operation of the PET signal processing circuit 8. During this time, the transmission of γ-ray imaging data is prohibited. After a few seconds or a few tens of seconds, the voltage is applied again and P
The operation of the ET signal processing circuit 8 is restarted, and the transmission of the γ-ray imaging data is permitted.

(Step 13) After restarting the PET inspection, prior to the CT inspection, a current is passed through the filament with the switch 60 of the X-ray generator 6 closed to emit thermoelectrons, and the positive electrode as the target. The voltage is applied between and to accelerate the thermoelectrons to collide with the target and generate X-rays. The X-ray generation intensity is stabilized at a predetermined value (tube current, tube voltage) and put in a standby state. Then, the body-axis-direction moving mechanism 61 is extended to position the X-ray generator 6 at a predetermined position (z in FIG. 1).
= Z1).

(Step 14) The radiation detector 5 included in the area irradiated with X-rays is connected to the CT signal processing circuit 9, the CT signal processing circuit 9 is operated, and X-ray imaging data (see Table 2) is obtained. get. Since the X-ray generator 6 emits X-rays with a spread of about 5 ° in the body axis direction and about 60 ° in the circumferential direction, the body axis direction irradiation region 6Z1 of FIG. 1 and the circumferential direction irradiation of FIG. A plurality of radiation detectors 5 included in the region 6A are connected to the CT signal processing circuit 9 (by switching the radiation detectors 5 as a radiation detector group 5i1 and the like collectively, a spread of 5 ° in the body axis direction (6Z1 , 6Z2) are processed together. The X-ray generator 6 is opened by opening the switch 60 of the X-ray generator 6 and rotating the circumferential movement mechanism 62 in the circumferential direction.
And make a CT examination.

When the X-ray generator 6 is rotationally moved, the irradiation area irradiated with X-rays is changed with time. Therefore, each radiation detector 5 located in the X-ray irradiation area is
The circuits are individually switched to detect X-rays.

For example, since the radiation detector groups 5i1 and 5j1 are included in the X-ray irradiation area at the time of starting the CT inspection, they are switched to the CT signal processing circuit 9 at the time of starting the CT inspection (γ ray → X. line). In this state, when the X-ray generator 6 rotates clockwise in FIG. 9, the radiation detector group 5i1 moves to X
When the radiation detector group 5i1 is separated from the irradiation area of the line, the circuit switching element 71 causes the radiation detector group 5i1 to be connected to the PE.
It is switched to the T signal processing circuit 8 and functions as a radiation detector group for detecting γ rays (X rays → γ rays). When the X-ray generator 6 rotates clockwise, the radiation detector group 5k
1 enters the X-ray irradiation area. At this time, the circuit switching element 71 switches the connection destination of the radiation detector group 5k1 to the CT signal processing circuit 9 and functions to detect X-rays (γ-ray → X-ray). Further, as the rotation progresses, the radiation detector groups 5i1 and 5j1 which once deviate from the irradiation area again enter the X-ray irradiation area. At this time, the connection destination is switched from the PET signal processing circuit 8 to the CT signal processing circuit 9 (γ ray → X
line). That is, the connection destination of the radiation detector group 5x is switched in synchronization with the movement (rotation) of the X-ray generator 6.

The CT / PET controller 10 issues a switching command to the circuit switching element 71, but the timing of rotation of the X-ray generator 6 and switching of each radiation detector group (5i1, 5j1 ...). Since the inspection sequence is structured so that the two are synchronized, the switching command is issued without detecting the position of the X-ray generator 6. That is, since the rotation start time and the rotation speed (angular speed) of the X-ray generator 6 are known, the circuit switching timing of each radiation detector 5 can be set in the sequence program, and the switching command can be set. It is supposed to be sent to 72.

Incidentally, for the radiation detector 5 switched to the CT signal processing circuit 9, the X-ray generator controller 65 adds the address information of the X-ray generator 6 at the detection time to the X-ray generator 5. X-ray imaging data (see Table 2) is CT / PE
It is transmitted to the T control device 10.

(Step 15) The switch 60 of the X-ray generator 6 is closed to stop the rotation and complete one slice, and at the same time, the radiation detector 5 connected to the CT signal processing circuit 9
Is switched to the PET signal processing circuit 8, the transmission of the γ-ray imaging data (see Table 1) is permitted, and the PET inspection is restarted.
The output of the X-ray tube is stopped, and the body axis direction moving mechanism 61 is contracted to retract it to the end of the image pickup apparatus 2. Alternatively, it may be moved to the next slice position.

Steps 11 to 15 (step 12)
Is not required), and after about 20 minutes, a CT examination is performed at z = z2 in FIG. When z = z2, the radiation detector 5 included in the irradiation region 6Z2 in the body axis direction is C
It becomes a connection target to the T signal processing circuit 9. Here, the radiation detector group 5i included in the body-axis direction irradiation region 6Z2
2, 5j2 and 5k2 are 5i1, 5j in (step 14)
This corresponds to 1,5k1. After the CT inspection is completed at z = z2, the PET inspection is executed again to end the CT / PET inspection.

The CT / PET controller 10 uses the γ-ray imaging data received from the PET signal processing circuit 8 to perform PE processing.
An X-ray CT image of the T image is reconstructed using the X-ray imaging data obtained from the CT signal processing circuit 9.

In order to obtain an X-ray CT image, the attenuation factor of X-ray is used based on the X-ray imaging data, and the X-ray generator 6 and the semiconductor element portion of the radiation detector 5 which has detected the X-ray are used. The linear attenuation coefficient in the body at is calculated. Using this line attenuation coefficient,
The linear attenuation coefficient of each voxel is obtained by a method such as the filtered back projection method. The CT value in each voxel is obtained using the value of the line attenuation coefficient of each voxel. X-ray CT image data can be obtained using these CT values.

To obtain the PET image, the number of annihilation γ ray pairs in the body between the semiconductor elements of the radiation detectors 5 is obtained using the count value of the γ ray imaging data. The γ-rays generated in the affected area are absorbed and attenuated while passing through the body, so by estimating these effects from the above-mentioned attenuation rate data and correcting the count value of the γ-ray imaging data, it is possible to obtain higher accuracy. It is also possible to obtain the count value of the γ-ray imaging data. This annihilation γ-ray pair is back-projected by a method such as a filtered back projection method to obtain the annihilation γ-ray pair generation density of each voxel. The disappearance γ ray pair generation density of each voxel is PET image data.

The PET image and the data of the X-ray CT image are combined to obtain a combined tomographic image including both data, which is displayed by the display device 11.

The PET image data and the X-ray CT image data can be combined easily and accurately by aligning the positions of the central axes of the holes 50 in both image data. That is, PET image data and X-ray CT
Since the image data is created based on the image pickup signal output from the shared radiation detector 5, the alignment can be accurately performed. Since the composite tomographic image displayed on the display device 11 includes the X-ray CT image, it is possible to easily confirm the position of the affected part in the PET image in the body of the subject 4. That is, since the X-ray CT image includes images of internal organs and bones, the position where the affected part (for example, a cancer affected part) exists is
It can be specified in relation to its internal organs and bones.

In this embodiment, since the X-ray generator 6 and the body-axis direction moving mechanism 61 are located inside the annular radiation detector 5, they block γ-rays emitted from the subject 4. The radiation detector 5 located right behind them has the γ
There is a possibility that the line cannot be detected and the data necessary for creating the PET image is lost. However, in the present embodiment, since the X-ray generator 6 and the body-axis direction moving mechanism 61 circulate in the circumferential direction, the loss of the data does not substantially pose a problem.
Especially, since the orbital speed of the X-ray generator 6 is about 1 second / slice, the PET usually requires at least several minutes of order.
Short enough compared to the inspection. Therefore, during the X-ray rotation irradiation, not only the target radiation detector 5 but also the total radiation detector 5
May be switched from the PET signal processing circuit 8 to the CT signal processing circuit 9 to simplify the circuit switching timing of the radiation detector 5.

In the present embodiment, γ-rays are incident on the radiation detector 5 even during X-ray inspection, but this γ-ray signal is sufficiently small compared to the X-ray signal intensity so that it can be ignored. This is C
The amount of charge generated per second by the γ-rays incident on one dTe, that is, the current is on the order of nA,
In the radiation detector 5 to which a voltage of several hundreds of volts is applied, the same dark current flows even if γ-rays are not detected, and X-rays are emitted so that a sufficiently large X-ray signal intensity can be obtained. Therefore, γ-ray incidence during X-ray signal detection can be sufficiently ignored.

As described above, according to the first embodiment, the CT / PET controller 1 is based on the information (see FIG. 8) input by the inspector.
By determining the inspection sequence (see FIG. 7) inside 0, and controlling the X-ray generator control device 65 and the circuit switching device 72 based on the sequence, a radiation inspection interweaving PET inspection and CT inspection is automatically performed. And P
It is possible to obtain a composite tomographic image of the ET image and the CT image. Further, the same radiation detector 5 is switched to detect γ-rays and X-rays, but the switching can be performed without detecting the position of the X-ray generator 6. Also, essentially the CT image and P
The ET images are extremely easy to combine, and the positional relationship between the two images is almost unchanged.

In the first embodiment, PET for 30 minutes is used.
It is a method that includes CT inspection twice during the inspection, but PE
The combination method of T inspection and CT inspection and each inspection time are not limited to those in the present embodiment. For example, z = z1, z2, z3, z4, z5 (z = 3 every few minutes during the PET examination 30 minutes.
By repeating the CT examination of 5 slices (not shown in FIG. 5 to 5), the tomographic image in each slice can be displayed with high positional accuracy. In addition, a CT examination is performed at the beginning of the examination and then P
You may perform only ET inspection.

[Second Embodiment] A radiation inspection apparatus 1A according to a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a diagram showing the configuration of the radiation inspection apparatus 1A of the second embodiment. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the radiation detector 5 has a radiation detector 5a on the inner peripheral side and a radiation detector 5b on the outer peripheral side. The radiation detector 5a is composed of, for example, a GaAs semiconductor detection element having a square shape with a side of 5 mm and a thickness of 1 mm, and the radiation detector 5b is composed of a 5 mm cubic GaAs semiconductor detection element (composed of a CdTe semiconductor detection element). Is also good). Radiation detectors 5a and 5b are holes 5
It is arranged in an annular shape so as to surround the body axis direction of 0 and the periphery of the hole 50. The radiation detectors 5b may be arranged in multiple layers in the radial direction.

The radiation detector 5a has a detecting portion made of GaAs having a small mass number and has a thin thickness of 1 mm.
The detection sensitivity for γ-rays of 511 keV, which is high energy, is lower than that of X-rays of 80 keV. In other words, most γ-rays pass without reaction even when γ-rays having higher energy than X-rays enter the radiation detector 5a for X-rays. Therefore, by using the radiation detector 5a, it is possible to selectively detect X-rays. Gamma rays are mainly radiation detector 5
detected in b. If the radiation detectors 5b are arranged in a plurality of layers in the radial direction, the thickness is effectively increased, and it becomes possible to detect γ rays.

Therefore, the radiation detector 5a is provided with the CT signal processing circuit 9 and the PET signal processing circuit 8, and the radiation detector 5b is provided with only the PET signal processing circuit 8. Therefore, the radiation detector 5a includes the circuit switching element 7
1 and the circuit switching device 72 to switch between γ rays and X
Alternately detect lines. On the other hand, the radiation detector 5b has the effect of reducing the number of circuits because it is not necessary to switch the CT signal processing circuit 9 and circuits, and the PET inspection is always performed during the CT / PET inspection, and the γ-ray imaging data is transmitted. To do.

That is, in the second embodiment, the radiation detector 5a is switched like the radiation detector 5 of the first embodiment (see FIG. 1) to detect γ rays and X rays. Further, the radiation detector 5b constantly detects γ-rays regardless of the presence or absence of X-ray irradiation. As a result, the PET inspection and the CT inspection can be reliably performed as in the first embodiment.

[Third Embodiment] A radiation inspection apparatus 1B according to a third embodiment of the present invention will be described with reference to FIG. FIG. 11: is a figure which shows the structure of the radiation inspection apparatus 1B of 3rd Embodiment. The same parts as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 11, only the CT signal processing circuit 9 is provided in the radiation detector 5a and P is provided in the radiation detector 5b.
Only the ET signal processing circuit 8 is prepared, and the circuit switching element 71 and the circuit switching device 72 are omitted. In this case, the radiation detector 5a and the CT signal processing circuit 9 operate only during the CT inspection and permit the X-ray imaging data transmission. On the other hand, the radiation detector 5b always performs the PET inspection and transmits the γ-ray imaging data. According to the third embodiment, circuit switching is completely unnecessary and the inspection sequence is simplified. Of course, as in the first and second embodiments, P
ET inspection and CT inspection can be performed.

[Fourth Embodiment] A radiation inspection apparatus 1C according to a fourth embodiment of the present invention will be described with reference to FIGS. 12 and 13. FIG. 12 is a radiation inspection apparatus 1C of the fourth embodiment.
It is a figure which shows the structure of. FIG. 13 is a diagram showing a detailed configuration around the radiation detector 5 such as the radiation detector 5, the first switching element 731, and the detector bias power supply 52 according to the fourth embodiment. The same parts as those of the first to third embodiments are designated by the same reference numerals and the description thereof will be omitted.

Each radiation detector 5 of the radiation inspection apparatus 1C according to the fourth embodiment has the first circuit switching element 7 by the wiring 51.
31 (see FIG. 13) and is connected to either the PET signal processing circuit 8 or the CT signal wiring 53. The CT signal wiring 53 extending from each radiation detector 5 is connected to the CT signal processing circuit group 9A by the second circuit switching element 741.

The CT signal processing circuit group 9A is a set of CT signal processing circuits 9 (see FIG. 5), and has a number of CT signals corresponding to the number of radiation detectors required to obtain one slice of CT examination. The processing circuit 9 (see FIG. 5) is provided inside. Therefore, although there are as many CT signal wirings 53 as there are total radiation detectors 5, only those necessary for one slice acquisition are connected to the CT signal processing circuit group 9A. CT
The CT signal wiring 53 connected to the signal processing circuit group 9A is determined by the slice position, that is, the position of the X-ray generator 6. For example, when the X-ray generator 6 is at z = z1, all the radiation detectors 5 included in the irradiation region 6Z1 in the body axis direction.
The CT signal wiring 53 corresponding to the CT signal processing circuit group 9
It becomes the connection target with A.

The first circuit switching device 73 and the second circuit switching device 74 receive the signal designating the number of the radiation detector 5 to be the circuit switching target of the CT / PET control device 10, and based on the designation, the first circuit switching device 73 and the second circuit switching device 74 receive the signal. It controls the operation of the first circuit switching element 731 and the second circuit switching element 741. The other configuration of the radiation inspection apparatus of the fourth embodiment is the same as that of the first embodiment, and thus the description thereof will be omitted.

CT / PET in the fourth embodiment
The inspection sequence will be described with reference to FIGS. 7, 12 and 13. In addition, as in the first embodiment, the PET inspection is performed three times.
It is assumed that imaging is performed mainly at the region from the chest to the abdomen of the subject at the timing of performing 0 minutes and performing CT examination twice (10 minutes and 20 minutes after the start of the examination) in the middle.

(Step 20) The subject 4 laid on the bed 31 moves to a predetermined position. A voltage (several hundreds) is applied to the radiation detector 5 by the radiation detector bias power source 52.
V) is applied, and the total radiation detector 5 is connected to the PET signal processing circuit 8 by the first circuit switching device 73.

(Step 21) The PET signal processing circuit 8 is operated by the CT / PET controller 10 to start the PET inspection. The γ-ray detected by the radiation detector is PE
The γ-ray imaging data processed by the T signal processing circuit 8 is transmitted to the CT / PET controller 10.

(Step 22) The radiation detector bias power supply 52 is set to 0 V, and the operation of the PET signal processing circuit 8 is stopped. During this time, the transmission of γ-ray imaging data is prohibited.
After a few seconds or a few tens of seconds, the voltage is applied again, the operation of the PET signal processing circuit 8 is restarted, and the transmission of the γ-ray imaging data is permitted.

(Step 23) Prior to CT inspection, X
With the switch 60 of the line generator 6 closed, a current is passed through the filament to emit thermoelectrons, and a voltage is applied between the filament and the positive electrode which is the target to collide the thermoelectrons with the target to generate X-rays. The X-ray generation intensity is stabilized at a predetermined value (tube current, tube voltage) and put in a standby state. Then, the body-axis-direction moving mechanism 61 is extended to move the X-ray generator 6 to a predetermined position (z = z1 in FIG. 12). CT signal wiring 53 (corresponding to CT signal wiring group 53Z1 here) and CT signal processing circuit group 9A corresponding to all the radiation detectors 5 included in the body axis direction irradiation region 6Z1 of the X-ray generator 6.
Are connected by the second circuit switching device 74.

(Step 24) The radiation detector 5 included in the area irradiated with X-rays is connected to the CT signal wiring 53 by the first circuit switching device 73, and the CT signal processing circuit group 9 is connected.
A is operated to acquire an X-ray imaging signal. X-ray generator 6
The switch 60 is opened and the circumferential movement mechanism 62 is rotated in the circumferential direction to orbit the X-ray generator 6 to perform a CT examination. Here, since the radiation detector group in the area irradiated with X-rays changes momentarily with the rotational movement of the X-ray generator 6, the circuits of the radiation detectors 5 are individually switched. CT
For the radiation detector 5 switched to the signal wiring 53, the position (address information) of the X-ray generator 6 at the detection time is added from the X-ray generator controller 65 to obtain the X-ray imaging data. Is transmitted to the CT / PET controller 10 (see Table 2).

Since the first circuit switching operation timing of each radiation detector 5 described above is known if the rotation start time and rotation speed of the X-ray generator 6 are known, it can be set in the sequence program, and its command can be set. It becomes possible by transmitting a signal to the first circuit switching mechanism. Also, during the X-ray rotation irradiation, the radiation detectors 5 in all the regions irradiated with X-rays in one slice acquisition may be switched to the CT signal wiring 53 to simplify the first circuit switching timing of the radiation detectors 5. good.

(Step 25) The switch 60 of the X-ray generator 6 is closed to stop the rotation and complete one slice, and at the same time, the radiation detector 5 connected to the CT signal wiring 53.
Is switched to the PET signal processing circuit 8, the transmission of the γ-ray imaging data is permitted, and the PET inspection is restarted. The output of the X-ray tube is stopped, and the body axis direction moving mechanism 61 is contracted so that the X-ray tube is retracted to the end of the imaging device 2 (or it may be moved to the next slice position z = z2). CT signal wiring group 5 connected to CT signal processing circuit group 9A
3Z1 is separated, and C corresponding to all the radiation detectors 5 included in the body-axis direction irradiation area 6Z2 when the X-ray generator 6 is located at the slice position z = z2 of the next CT examination.
T signal wiring 53 (here, CT signal wiring group 53Z2
2) and the CT signal processing circuit group 9A are connected by the second circuit switching device 74.

Steps 21 to 25 (step 22)
Does not have to be entered) again, and next time z
= Z2, the CT inspection is performed, the PET inspection is executed again, and the CT / PET inspection is completed.

In the fourth embodiment, PET for 30 minutes is used.
It is a method that includes CT inspection twice during the inspection, but PE
The combination method of T inspection and CT inspection and each inspection time are not limited to those in the present embodiment. For example, z = z1, z2, z3, z4, z5 (z = 3 every few minutes during the PET examination 30 minutes.
5 are not shown in FIG. 12), the tomographic image in each slice can be displayed with high position accuracy by repeating the CT examination of 5 slices. Alternatively, the CT inspection may be performed at the beginning of the inspection, and only the PET inspection may be performed thereafter. For example, the CT inspection may be performed at the beginning of the inspection, and only the PET inspection may be performed thereafter.

As described above, according to the present embodiment, by switching the CT signal processing circuit group 9A by using the second circuit switching device 74, the minimum number of CT signal processing circuits necessary to obtain one slice in the CT inspection is obtained. Can always be used, which has the effect of reducing the number of CT signal processing circuits. Also, the second
The CT / PET inspection is performed on the radiation detector 5a and the PE is performed on the radiation detector 5b as described in the above embodiment.
When only the T inspection is performed, the first circuit switching device 73 and the first circuit switching element 73 are provided for the radiation detector 5b.
1 may be omitted and the PET signal processing circuit 8 may be directly connected. In this case, the CT signal wiring 53 is connected to the radiation detector 5a.
Just prepare for it. Further, as described in the third embodiment, when only the CT inspection is performed by the radiation detector 5a and only the PET inspection is performed by the radiation detector 5b, the CT signal wiring 53 is provided in the radiation detector 5a, Radiation detector 5
The PET signal processing circuit 8 may be directly connected to B.

According to the first to fourth embodiments described above, the inspection sequence is determined inside the radiation inspection control device (inside the CT / PET control device 10) based on the information (FIG. 8) input by the inspector. Then, by controlling the X-ray generator control mechanism and the circuit switching mechanism based on the sequence, a single imaging apparatus automatically performs a radiological examination that interlaces a plurality of radiological examinations such as a CT examination and a PET examination. It can be carried out. As a result, the obtained data can be aligned easily, and the device configuration is simpler than that of the conventional device that requires a plurality of imaging devices. Further, by consolidating the signal processing circuits used for a specific inspection into one circuit group and appropriately connecting only the radiation detectors targeted for the inspection, the number of signal processing circuits can be saved. . Also, the CT / PET controller 1
0 switches the connection destination (PET signal processing circuit 8, CT signal processing circuit 9) of the radiation detector 5 in synchronization with the movement (rotation) of the X-ray generator according to the self-generated inspection sequence. Since it is not necessary to switch the connection destination of the radiation detector 5 while monitoring the position of the X-ray generator 6, the configuration of the device can be simplified.

[0079]

According to the present invention, it is possible to provide a radiation inspection apparatus in which the position of each image is easily aligned and the apparatus configuration is simplified.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radiation inspection apparatus according to a first embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of the PET signal processing circuit shown in FIG.

FIG. 3 is an explanatory diagram showing an output waveform of the preamplifier circuit shown in FIG.

FIG. 4 is an explanatory diagram showing an output waveform of the low-speed waveform shaping circuit shown in FIG.

5 is a detailed configuration diagram of the CT signal processing circuit shown in FIG.

6 is an explanatory diagram showing an output waveform of the amplifier circuit shown in FIG.

FIG. 7 is an explanatory diagram showing a CT / PET inspection sequence of the radiation inspection apparatus according to the first embodiment of the present invention.

8 is an example of an information input screen for creating the CT / PET inspection sequence of FIG.

9 is a diagram quoted for explaining the operation of the CT / PET inspection sequence of FIG. 7 (I-I cross-sectional view of FIG. 1).

FIG. 10 is a configuration diagram of a radiation inspection apparatus which is a second embodiment of the present invention.

FIG. 11 is a configuration diagram of a radiation inspection apparatus which is a third embodiment of the present invention.

FIG. 12 is a configuration diagram of a radiation inspection apparatus which is a fourth embodiment of the present invention.

FIG. 13 is an explanatory diagram showing in detail the peripheral configuration of the radiation detector of the radiation inspection apparatus according to the fourth embodiment of the present invention.

FIG. 14 is a conceptual diagram of a radiation inspection apparatus in the related art.

[Description of Reference Signs] 1, 1A, 1B, 1C ... Radiation inspection apparatus, 2 ... Imaging apparatus, 30, 31 ... Bed, 32 ... Bed moving mechanism, 4, 40
... Subject, 5, 5a, 5b ... Radiation detector, 5i1, 5
j1, 5k1, 5i2, 5j2, 5k2 ... Radiation detector group, 51 ... Wiring, 52 ... Detector bias power supply, 53 ...
CT signal wiring, 53Z1, 53Z2 ... CT signal wiring group, 50 ... Hole portion, 6 ... X-ray generator, 60 ... Switch, 61
... Body axis direction moving mechanism, 62 ... Circumferential direction moving mechanism, 63 ... X
Line generator holder, 64 ... Circular movement rail, 65 ... X-ray generator control device, 6A ... Circumferential irradiation area, 6Z1, 6Z
2 ... Axial irradiation area, 71 ... Circuit switching element, 72 ... Circuit switching device, 73 ... First circuit switching device, 731 ... First circuit switching element, 74 ... Second circuit switching device, 741 ... Second circuit switching element , 8 ... PET signal processing circuit, 81 ... Preamplification circuit, 82 ... Low-speed waveform shaping circuit, 83 ... γ-ray discrimination circuit, 8
4 ... High-speed waveform shaping circuit, 85 ... Simultaneous counting circuit, 80 ... P
ET inspection device, 9 ... CT signal processing circuit, 91 ... Amplifying circuit, 92 ... Peak hold circuit, 90 ... CT inspection device,
9A ... CT signal processing circuit group, 10 ... CT / PET control device, 11 ... Display device

Continued front page    (72) Inventor Kikuo Umegaki             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Hiroshi Kitaguchi             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Yuichiro Ueno             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Shinichi Kojima             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Kazuma Yokoi             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. F term (reference) 2G088 EE01 KK28                 4C093 AA22 BA04 CA16 EB12 EB13                       EB18 EB20 EE01 FA06 FA15                       FA19 FA32 FA33 FA42 FA43                       FA44 FE06 FF35

Claims (13)

[Claims] 1. A bed on which a subject is placed, an imaging device,
A radiation inspection control device; and the imaging device, a second radiation generator that irradiates the subject with second radiation, a second radiation generator moving unit that moves the position of the second radiation generator, A plurality of radiation detectors for detecting two types of radiation, a first radiation emitted from the subject and a second radiation transmitted through the subject;
A signal processing circuit system including at least one of a first signal processing circuit that processes a first radiation detection signal and a second signal processing circuit that processes a second radiation detection signal for each of the radiation detectors; The radiation inspection control device moves the second radiation generator, starts and ends the second radiation irradiation by the second radiation generator, and performs signal processing timing of the first radiation detection signal in the signal processing circuit system and second. A radiation inspection apparatus having a function of controlling a signal processing timing of a radiation detection signal. 2. A bed on which a subject is placed, an imaging device,
A radiation inspection control device; and the imaging device, a second radiation generator that irradiates the subject with second radiation, a second radiation generator moving unit that moves the position of the second radiation generator, A plurality of radiation detectors for detecting two types of radiation, a first radiation emitted from the subject and a second radiation transmitted through the subject;
A first signal processing circuit system including at least one of a first signal processing circuit for processing a first radiation detection signal and a second radiation signal wiring for transmitting a second radiation detection signal to each of the radiation detectors; A plurality of second signal processing circuits for processing a second radiation detection signal transmitted from a first signal processing circuit system through the second radiation signal wiring are provided, and each of the second signal processing circuits includes a plurality of second signal processing circuits. A radiation inspection apparatus characterized in that an arbitrary second radiation signal wiring is selected from the radiation signal wirings and can be connected. 3. The radiation inspection control device controls movement of the second radiation generator, start and end of second radiation irradiation, signal processing timing of the first radiation detection signal, and transmission timing of the second radiation detection signal. The radiation inspection apparatus according to claim 2, further comprising a function of controlling, selecting a combination of the second radiation signal wiring and the second signal processing circuit, and controlling a timing of the selection. 4. The radiation inspection apparatus according to claim 1, wherein the radiation detector is a semiconductor radiation detector. 5. A bias voltage applying unit for applying an electrical bias to the semiconductor radiation detector is provided, and the radiation inspection control device has a function of instructing the bias voltage applying unit to supply and stop a bias. The radiation inspection apparatus according to claim 4, wherein: 6. The radiological inspection control apparatus controls the second
Radiation generator, second radiation generator moving mechanism, bias voltage applying means, first signal processing circuit, first
At least one of the signal processing circuit system and the processing command to be transmitted to the second signal processing circuit is transmitted at a timing based on the elapsed time from the start of the inspection. 1. The radiation inspection apparatus according to any one of claims 3 to 5. 7. The inspection sequence for determining the timing is created by the radiation inspection control device based on the radiation inspection information input by the inspector to the radiation inspection control device. Radiation inspection equipment. 8. The second radiation generator stabilizes the second radiation output so that the second radiation can be irradiated with a dose that does not change from the start to the end of irradiation before the irradiation start time to the subject. The radiation inspection apparatus according to any one of claims 1 to 7, characterized in that the radiation inspection apparatus is set in the opened state. 9. Data of a first tomographic image of the subject is created based on the first radiation detection data, and data of a second tomographic image of the subject is created based on the second radiation detection data. And a tomographic image data creation device that creates combined tomographic image data that combines the data of the first tomographic image and the data of the second tomographic image. Radiation inspection equipment. 10. The radiation inspection apparatus according to claim 1, wherein the first radiation is γ-rays. 11. The radiation inspection apparatus according to claim 1, wherein the second radiation is an X-ray. 12. The first tomographic image is a PET image,
The radiation inspection apparatus according to claim 9, wherein the second tomographic image is an X-ray CT image. 13. The first radiation emitted from the subject,
And the second radiation emitted from the second radiation generator and transmitted through the subject, by individually switching the output destinations of a plurality of radiation detectors arranged in a cylinder surrounding the subject. And a second radiation detecting method for detecting both of the second radiation, wherein when the second radiation generator is circularly driven to irradiate the second radiation, the radiation detector at the irradiation destination is irradiated with the second radiation. The second radiation generator is driven in a predetermined sequence so that the output destinations of the plurality of radiation detectors are individually switched in the predetermined sequence.