JP4231414B2 - Radiation imaging apparatus, radiation imaging system, imaging support method using radiation, and radiation detector - Google Patents

Description

Technical field
The present invention relates to a radiation imaging apparatus that captures radiation, a radiation imaging system including a radiation generation apparatus, an imaging method using radiation, and a radiation detector thereof.
Background art
Examples of conventional radiation imaging apparatuses using radiation include a film method and an imaging plate (IP) method (reference: RDIOISOTOPES: 44, 433 (1995)). The detectors that are sensors used in these methods are indirect imaging in which the sensitive part thickness of radiation is about several tens to several hundreds of μm, and development processing or image information reading processing by a laser is necessary after imaging. . Moreover, since the radiation imaging apparatus using such an indirect imaging method has a thin sensitive part thickness of radiation and low radiation detection sensitivity, a large amount of radiation is required for imaging. This does not adversely affect the human body, but there has been a desire to minimize the radiation exposure of the patient.
Therefore, in recent years, an imaging method using a flat panel sensor including a phosphor having a thickness of several hundreds of μm and a TFT (Thin Film Transistor) as a detector (reference document: IEEJ Technical Committee; Nuclear Research Society, NE-01-25, P21). (2001)) is attracting attention. This imaging method can obtain a real-time image and is called direct imaging in contrast to the indirect imaging described above. For this reason, radiation imaging devices capable of direct imaging are being widely used as important devices for group screening and medical diagnosis.
Further, the main purpose of use of the conventional radiation imaging apparatus is X-ray imaging of a patient, and the target energy of radiation is about 100 keV (effective average energy is about 50 keV). On the other hand, in recent nuclear medicine radiographic imaging techniques, there are a great number of diagnoses in which a patient is imaged by administering a radioactive substance (RI). In such imaging, Tc-99m (141 KeV) for gamma cameras, O-15 for PET (Positron Emission Tomography), and F-18 (511 keV) are the main RIs.
However, the above-described RI is a high energy source compared to the X-ray energy used for X-ray imaging. For this reason, when imaging is performed with such a radiation source using a conventional radiation imaging apparatus, the sensitivity of the detector is further insufficient, so that the imaging time becomes longer and patient exposure may become a problem. . Further, depending on the type of radiation source, sufficient detection sensitivity cannot be ensured, and a necessary image may not be obtained. From such a point of view, there is a demand for the development of a radiation imaging apparatus including a detector that has appropriate sensitivity to the radiation source to be used.
In addition, there are many X-ray / nuclear medicine imaging targets, ranging from the entire chest area of the largest area to the gallbladder and kidney of the smallest area. Manufactured to fit the large breast area. However, such large detectors are inconvenient to handle. Further, when a small part such as a kidney is to be imaged, other unnecessary parts are also imaged, and there has been a demand for imaging only a necessary part. Such a demand is conspicuous in local imaging performed during surgery. And in order to meet such a demand, it is necessary to prepare all types of radiation sources, detectors suitable for the area of the imaging target, and radiation imaging apparatuses equipped with such detectors. If there are 3 types of energy, 30 types of imaging sites (imaging organs, etc.), 3 types of body shapes of infants, children, and adults, you will have to own 270 types of radiation imaging devices in advance, storage space, It is not desirable from the viewpoint of management costs.
Accordingly, an object of the present invention is to flexibly cope with imaging conditions and to obtain a necessary image promptly in imaging performed using radiation. Another object of the present invention is to minimize the exposure amount of the person to be imaged by flexibly responding to the imaging conditions.
Disclosure of the invention
As a means for solving the above-described problem, there is a radiation imaging apparatus in which a square detector is arranged in accordance with an imaging target to constitute a radiation detector. The detection element is preferably attached to the holder as a detection module. If the detection modules are arranged on the basis of the imaging parameters such as the type of radiation source, the body shape of the imaging target, the imaging site, etc., it becomes possible to reliably obtain the necessary image. As the detection element, either a compound semiconductor such as CdTe, CZT, or GaAs, or a semiconductor such as Si can be used. Furthermore, the radiation imaging apparatus desirably includes a holder for arranging the detection modules. As such a holder, a configuration including a plate and a slot for positioning the detection module while sliding the detection module can be given. If the gap between the detection elements when the detection modules are arranged on the holder is 2 mm or less, the gap at the time of arrangement can be minimized and a necessary image can be obtained with certainty. In addition, if the detection module is provided with a concave portion or a convex portion for assisting the arrangement, the arrangement work is facilitated. Here, the arrangement of the detection modules may be performed manually, but a handling mechanism is provided to automatically carry the detection module from the storage position to the holder, and when assembled, the detector can be set up quickly. It becomes possible.
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a radiation imaging system in the present embodiment. FIG. 2 is a conceptual diagram when the radiation imaging apparatus is used as an X-ray imaging apparatus.
As shown in FIG. 1, the radiation imaging system 1 detects an X-ray generator 2 that emits X-rays as radiation, and X-rays that have passed through a specific part (imaging target) of a patient, and outputs an image thereof. And the radiation imaging apparatus 3. Further, as shown in FIG. 2, a holding means (not shown) for holding the bed 4 on which the person to be imaged lies, the X-ray generator 2 and the like may be included. The holding means is composed of a C-shaped arm or the like, and the X-ray generator 2 and its detector 6 are fixed opposite to each other at both ends of the arm. Radiation imaging can be performed by advancing and retracting such an arm with respect to the imaging target W of the patient or rotating it in the X and Y directions. Note that in the radiation imaging apparatus 3 used for gamma camera that administers RI (radioactive substance) to a patient and SPECT (Single Photon Emission CT) imaging, radiation is emitted from the imaging target itself, so the X-ray generator 2 Is no longer necessary.
A radiation imaging apparatus 3 illustrated in FIG. 1 includes a detector 6 that detects radiation from an imaging target, a data collection apparatus 7 that functions as an interface for collecting imaging data that is output from the detector 6, and a captured image. A processing device 8 that is a computer that performs creation of the image and a display device 9 that is an output unit that displays the created captured image, and includes an operator console 10 that operates each part and inputs parameters during imaging. Yes. Furthermore, the detector 6 includes a module detection unit 11 that is a detection module that images an imaging target with one or a plurality of aggregates, and a holder 12 that holds the module detection unit 11.
The structure of the module detection part 11 is demonstrated using FIG. 3 and FIG. 3 is a configuration diagram of the module detection unit, and FIG. 4 is a view taken along the line AA in FIG.
As shown in FIG. 3, the module detection unit 11 constituting the detector 6 includes a detection element 21 that is a plate-like and square detection surface that generates electric charges (electron-hole pairs) upon incidence of radiation, and a detection element. A readout circuit 22 for reading out electric charges from 21 and an information controller 23 functioning as an interface for smoothly transferring a large amount of two-dimensional information from the detection element 21 are not shown in FIG. It is accommodated in a housing (see FIG. 2), and is connected to the data collection device 7 (see FIG. 1) by a cable 24.
As shown in FIG. 4, the detection element 21 has a width W, a length L, and a thickness t, and is arranged so as to sandwich the semiconductor 21 a between the semiconductor 21 a that is a detection unit that absorbs radiation and generates charges. In addition, a cathode electrode 21b and an anode electrode 21c that apply an electric field to the semiconductor 21a in order to extract electric charge are provided. As the semiconductor 21a, for example, a compound semiconductor such as CdTe (cadmium telluride), CZT (cadmium telluride), GaAs (gallium arsenide), or a semiconductor such as Si is used. The cathode electrode 21b is formed on the entire surface of the semiconductor 21a using a gold or platinum film. The anode electrode 21c is formed independently so that a signal for each region (pixel) divided into each mesh can be taken out. For example, when the area of the semiconductor film 21a is 40 × 40 mm and the anode electrode 21c is formed to have a 0.2 mm mesh, the number of nodes becomes 40000. The electric charges generated when radiation is incident on the semiconductor 21a are taken out from the respective nodes, read in real time as detection signals, and become two-dimensional radiation image information (imaging data described above). The total number of pixels of the image created using 11 is 40000 pixels. Note that an applied voltage for generating an electric field in the semiconductor element 21a is supplied from the data collection device 7 via the high voltage supply wiring 21d shown in FIG.
The reading circuit 22 shown in FIG. 3 is composed of an ASIC (Application Specific IC) or LSI. In order to individually collect detailed two-dimensional information, bumps (fine ball solder) 25 are used to connect the readout circuit 22 and the anode electrode 21c. The readout circuit 22 and the information controller 23 are sized so as not to protrude from the detection element 21 in order to minimize the insensitive portion (portion where an image cannot be obtained) when the module detector 11 is used in combination.
A housing 26 shown in FIG. 2 is for integrally housing and holding the detection element 21 including the high-voltage supply wiring 21d, the data read circuit 22, and the information controller 23, from 0.5 mm. It has a plate thickness of about 1 mm. A cable 24 extending from the extraction unit 27 on the back of the module detection unit 11 transmits a signal from the information controller 23 to the data collection device 7 and supplies a voltage from the data collection device 7 to the detection element 21 and the like. Used for. The cable 24 includes a connector and is preferably detachable from the take-out portion 27 of the housing 26.
Here, in the present embodiment, a small detector 6 that is easy to handle and suitable for intraoperative imaging or the like by arbitrarily combining the module detectors 11 to form the optimum and minimum detector 6. Is realized. This will be described with reference to the schematic diagram of FIG.
The size of the imaging target of the radiation imaging apparatus 3 varies greatly depending on the part (organ or bone). For example, FIG. 5A shows a result of imaging the chest, that is, the lung W1, as an imaging target. This figure also shows the combination of the module detection units 11, and each square cell corresponds to the detection element 21 of the module detection unit 11. That is, since the lung W1 is the largest object to be imaged, a total of sixteen module detectors 11 in the vertical and horizontal directions are mounted in combination with the holder 12, and imaging is performed by forming a substantially square imaging region. Yes. Note that since the lattice-shaped region 29 is a non-sensitive portion where an image cannot be obtained by the housing 26 of the module detection unit 11, an actual image cannot be obtained. It is possible to sufficiently compensate by processing of the image processing software. In order to minimize the area 29, it is desirable that the module detection units 11 are arranged so that the adjacent module detection units 11 are in contact with each other. At this time, the region 29 can be made the smallest when the housing 26 is not provided on the outer periphery of the detection element 21, and the width of the region 29 is “0 mm”. On the other hand, when the outer periphery of the detection element 21 is covered with the housing 26 and the insensitive part is compensated by image processing, the width of the region 29 is preferably within “2 mm”. This is to prevent oversight of a lesion due to the fact that a real image cannot be obtained.
Similarly, FIG. 5B shows a result of imaging using eight module detection units 11 with the stomach W2 as an imaging target. In this case, the module detection unit 11 is composed of a total of eight, three, one, and three rows from the lower portion to the upper portion of the stomach W2 so that the end portions of each row are aligned. Further, if the imaging target is the liver W3 shown in FIG. 5 (c), the imaging is performed by combining the module detection units 11 in two rows of three. The imaging objects are the kidney W4 (FIG. 5 (d)), the pancreas W5 (FIG. 5 (e)), and the hand W6 (FIG. 5 (f)). Two rows and two rows are combined and imaged. Here, when imaging the pancreas W5, since the shape is elongated, the two module detectors 11 in the first row and the two module detectors 11 in the second row are shifted by one module detector. Are combined. On the other hand, when imaging the hand W6, since the outer shape of the hand W6 is close to a square, the module detection unit 11 is combined so that two rows of two are arranged in parallel.
Furthermore, in order to minimize the amount of exposure of the patient or obtain a clearer image, it is necessary to optimize the sensitivity of the detection element 21, and this is related to the energy of the radiation source (FIG. 6) and detection. This will be described with reference to the relationship between the thickness of the element 21 and the amount of absorbed radiation (FIG. 7). Since the thickness of the cathode electrode 21b and the anode electrode 21c shown in FIG. 4 is sufficiently thinner than the semiconductor element 21a, the thickness of the detection element 21 will be described as synonymous with the thickness of the semiconductor element 21a for detection.
As is apparent from FIG. 6 showing main medical radiation sources used in nuclear medicine, the energy of the radioactive material (RI) source can be divided into three regions of 80 keV, 150 keV, and 500 keV. Further, when an X-ray source is used, the energy is about 75 keV to 140 keV. Since the generated energy of the X-ray source indicates the maximum energy, the effective energy (average energy) is about ½ or less of the maximum energy. That is, the effective energy of the X-ray source is 40 to 70 keV. Since the amount of absorption per unit thickness of the detection element 21 varies depending on the magnitude of energy, the optimum detection element thickness is used for these energy regions, that is, the thickness of the detection surface is set according to the energy region. It is desirable to choose.
Generally, in order to obtain sufficient imaging sensitivity for each incident radiation energy, an absorption amount of at least 10% is required. Here, when the thickness (t) of the detection element 21 increases, it is necessary to increase the collection voltage (V) of charges generated by the incidence of radiation. This relationship is slightly different depending on the material constituting the semiconductor element 21a, but is approximately t∝V. The S / N of radiation detection depends on the leakage current Id, but the relationship between Id and V is IdＩ√V (= √t). Therefore, the S / N of radiation detection tends to be worse at 1 / √t. That is, it can be seen from these relationships that it is necessary to select the module detection unit 11 having the optimum detection element thickness according to the energy of the radiation used for imaging.
When CdTe is used as the semiconductor element 21a, the relationship between the thickness of the detection element 21 and the amount of absorbed radiation as shown in FIG. 7 is obtained. Assuming that the amount of absorbed radiation is 10% or more, a detection element of 5 mm thickness for 500 keV, 2 mm thickness for 150 keV, and 1 mm or less for 80 keV or less can be selected as the optimum. Thus, if the S / N is optimized by selecting the detection element thickness for each radiation energy, the imaging time can be shortened, and thus the exposure dose of the imaging patient can be greatly reduced. In the present embodiment, a small-area module detection unit 11 is prepared corresponding to the energy of radiation, and the combination of the module detection unit 11 is changed to suit the radiation source, imaging area, body shape of the subject, and the like. The optimal imaging device can be easily realized.
The holder 12 shown in FIG. 1 is used for arranging the module detection units 11 used for imaging and maintaining the arrangement state. An example of such a holder 12 will be described with reference to FIGS. FIG. 8A is a side view of the holder, and FIG. 8B is a front view of the holder.
As shown in FIGS. 8A and 8B, the holder 12 has a housing 31 that contacts at least one of the back surface and the side surface of the module detection unit 11. The housing 31 has a bottom surface 32, a side surface 33, a back surface 34, and a top surface 35. Although it is desirable not to provide a side surface on the surface facing the side surface 33, it may have a side surface. The reason why the side surface is not provided on the surface facing the side surface 33 is to facilitate the attachment of the module detection unit 11 to the holder 12.
The back surface 34 is a plate with which the back surface of each module detection unit 11 abuts in order to arrange the detection elements 21 on the same plane, and the cable 24 of the module detection unit 11 is taken out or used for positioning the module detection unit 11. A long hole 36 is provided. The long holes 36 are formed in accordance with the arrangement direction of the module detection units 11. For example, if the holder 12 can arrange the four module detection units 11 in four rows, the four long holes 36 are arranged. Is done. The long hole 36 does not necessarily have to penetrate the back surface 34. Further, in FIG. 8, the shape is elongated in the horizontal direction, but may be elongated in the vertical direction.
When the module detectors 11 are arranged in the holder 12 shown in FIG. 8, the cable 24 is taken out into the elongated hole 36 with a gap between the module detectors 11 adjacent to each other as shown by a broken line in the figure. Then, the module 27 is slid in the direction of the arrow along the long hole 36. When the take-out part 27 comes into contact with one end of the long hole 36, the module detection part 11 is positioned, the adjacent module detection parts 11 come into contact, and the module detection parts 11 continuous in the vertical direction are arranged. The module detector 11 is slid because it can be easily mounted without touching the detection element 21 during mounting. A means for gripping the takeout part 27 and a fitting part with the takeout part 27 may be provided on the back surface 34 in order to prevent the positioned module detector 11 from moving. Note that the cable 24 of the module detection unit 11 is configured to be detachable, and is preferably attached to the take-out unit 27 after positioning of the module detection unit 11 with respect to the holder 12 is completed.
The holder 12 is a holder that can target the lung W1 in FIG. 5A. However, the detector 6 for the purpose of intraoperative imaging, the detector 6 that does not need to image the lung W1, and the like. In this case, it is possible to make the holder 12 of any shape. Examples of such a holder 12 include a holder that can arrange the module detectors 11 in a maximum of three in two rows, and a holder that can be arranged in a maximum of four in three rows.
A processing device 8 shown in FIG. 1 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory) for data processing, a predetermined electric / electronic circuit, and a ROM (Read Only Memory) for storing data and programs. ) And a hard disk, and various drive devices for reading and writing data may be included. The storage device stores a database that is used when selecting imaging conditions in response to input of imaging parameters described later. This database is a table constructed by associating imaging parameters and imaging conditions. When a database search is performed using a set of imaging parameters as a keyword, a set of imaging conditions can be obtained.
Here, as imaging parameters, “selection of X-ray imaging and RI imaging”, “type of radiation to be used”, “dose / administration time to patient in the case of RI imaging”, “imaging target”, “patient No body shape ". Among these, “type of radiation to be used” is used to select the module detection unit 11 having the optimum detection element thickness. “Dose / administration time to patient in the case of RI imaging” is used to determine the imaging time. Since a medical RI having a short half-life as shown in FIG. 6 is used, the radiation dose emitted from the RI according to the time elapsed from the administration time to imaging, that is, the radiation dose emitted from the imaging target Changes. For this reason, by obtaining the administration time, the elapsed time from the administration to imaging is calculated from the current time of the internal timer, and the optimum imaging time is determined. As described above, the “imaging target” is used to determine the number and combination of the module detection units 11 according to the site. “Patient body shape” refers to the height, weight, age, sex, etc. of the patient. Depending on whether the patient is a child, an adult, or a woman, the measurement position and necessary module detection This is used to modify the number and combination of the parts 11.
As imaging conditions, radiation energy and imaging time, arrangement (in combination with the number) of the module detection unit 11, aperture when the radiation source is an X-ray source, collimator arranged in the module detection unit 11 when using RI Installation conditions. The installation conditions of the collimator determine the aperture diameter and its direction based on the position of the imaging target, the energy of radiation, and the like.
Next, imaging processing in the radiation imaging system 1 using the radiation imaging apparatus 3 will be described mainly using the flowchart of FIG.
First, as step S1, the radiation imaging apparatus 3 acquires imaging parameters. This process is performed when a doctor or an X-ray imaging engineer inputs various imaging parameters from the operator console 10 (see FIG. 1).
In step S2, the processing device 8 automatically determines imaging conditions based on the various imaging parameters input in step S1 and causes the display device 9 to display them. That is, the processing device 8 performs a database search using the imaging parameters, determines the number of module detection units 11 based on the size of the imaging target, and determines the number of module detection units 11 according to the shape (type) of the imaging target. Determine the dimension array. In addition, the imaging time is determined as described above, and the module detection unit 11 having a different detection element thickness (detection surface thickness) is determined as necessary.
In step S <b> 3, the processing device 8 waits for input of approval / disapproval of the presented imaging condition. That is, the doctor or the X-ray imaging engineer confirms the imaging conditions displayed on the screen, and if it is determined that correction is necessary (NO in step S3), the process proceeds to step S4. On the other hand, if it is determined that no correction is necessary (YES in step S3), the imaging conditions are approved, and the process proceeds to step S5. The confirmation at this time is input from the operator console 10.
The manual correction of the imaging condition in step S4 can be performed for each item such as the imaging time with respect to the imaging condition displayed on the screen. The operator console 10 is operated to move the cursor to the item to be corrected and necessary. This is done by entering a simple number or selecting from the displayed choices. For example, the arrangement of the module detection unit 11 is displayed as candidates such as an array rotated 90 degrees with respect to the array shown in FIG. After the manual correction is performed, the process returns to step S3 again and waits for input of approval / disapproval of the imaging condition.
In step S5, imaging preparation is performed based on the authenticated imaging condition. The processing device 8 outputs a control signal for moving the holder 12 of the module detection unit 11 to the measurement position facing the target site, or turns on a lamp that notifies the start of imaging. The module detector 11 is preferably mounted before the holder 12 is moved.
In subsequent step S6, imaging is performed. In the case of using the X-ray generator 2, the imaging time is counted from the emission of X-rays, and in the case of RI, the imaging time is counted from the time when the module detection unit 11 is arranged at the measurement position. When imaging is performed, the detection element 21 of the module detection unit 11 generates an electric charge according to the incidence of radiation. This electric charge is transmitted to the processing device 8 for each module detection unit 11 via the cable 24, and the processing device 8 processes the image data and causes the display device 9 to display an image of the imaging region.
Further, in step S7, an imaging end process is performed. When the imaging time is completed, necessary processing such as output stop of the X-ray generator 2, separation of the module detection unit 11 from the measurement position, and image data collection stop of the processing device 8 is performed. At this time, the photographed image is temporarily held in the processing device 8, and is stored in a storage device, an external recording medium, or output to a printing device as necessary.
The radiation imaging system 3 including the radiation detector 6 or the radiation imaging apparatus 3 including the detector 6 or the X-ray generation apparatus 2 has various conditions such as a patient's body shape and an imaging region. However, the imaging conditions can be easily set, and more practical imaging can be performed efficiently. In addition, the process including acquisition of imaging parameters, determination of the number and arrangement of the module detection units 11, selection of the detection element thickness performed as necessary, and arrangement of the module detection units 11 on the holder 12 in the above. Is the assembly process of the detector 6.
(Second embodiment)
A second embodiment of the present invention will be described in detail with reference to the drawings. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 10 is a diagram schematically showing the overall configuration of the radiation imaging apparatus in the present embodiment. As shown in FIG. 10, the radiation imaging apparatus 51 includes a detector 6 including module detection units 11 a, 11 b, 11 c that capture an imaging target and its holder 12, a data collection apparatus 7 connected to the detector 6, A processing device 8 that creates a captured image, a display device 9 that displays the created captured image, module trays 52a, 52b, and 52c for storing the module detectors 11a to 11c, and module trays 52a and 52b , 53c, a handling mechanism 53 for taking out the necessary module detection units 11a to 11c and mounting them on the holder 12, and an operator console 10 for operating each unit and inputting parameters at the time of imaging.
As the module detection unit in the present embodiment, three types of module detection units 11a, 11b, and 11c having different thicknesses of the semiconductor element 21a of the detection element 21 shown in FIG. These three types of module detectors 11a, 11b, and 11c are 1 mm thick, 2 mm thick, and 5 mm thick so that good sensitivity can be obtained with respect to the three types of energy (80 keV, 150 keV, and 500 keV) shown in FIG. is there. Further, three module trays 52a, 52b, and 52c are also provided in order to distinguish and store the three types of module detectors 11a, 11b, and 11c having different film thicknesses.
The handling mechanism 53 includes a manipulator 55 including a grip-type hand 54 that conveys the module detection units 11a, 11b, and 11c between the module trays 52a, 52b, and 52c and the holder 12. Specific examples of such a handling mechanism 53 include a rail laid from the module trays 52a, 52b, 52c to the holder 12, and a manipulator 55 mounted on a traveling carriage movable on the rail. Examples include indirect robots, various motors that drive each joint of the traveling cart and the multi-indirect robot. The position of the hand 54 is controlled by a control signal output from the processing device 8. Therefore, the processing device 8 includes the position of the holder 12, the positions of the module trays 52a, 52b, and 52c, and the types of the module detection units 11a, 11b, and 11c stored in the module trays 52a, 52b, and 52c. Etc. are registered in advance. It should be noted that it is possible to adopt a rectangular coordinate robot instead of the multi-indirect robot or other known means for moving the hand 54 in the horizontal direction or the vertical direction by other numerical control. It is good also as a structure which conveys the module detection parts 11a-11c by rotating the manipulator 55, without providing the rail and traveling carriage which slide the manipulator 55. FIG.
Each of the module trays 52a, 52b, and 52c is provided with an accommodation hole 56 that accommodates and stores the maximum number of the module detection units 11a, 11b, and 11c that can be attached to the holder 12. That is, if the maximum imaging area is 40 × 40 cm and one imaging area of the module detectors 11a, 11b, and 11c is 4 × 4 cm, one type of module trays 52a, 52b, and 52c are each provided with one hundred accommodating holes 56. One hundred module detectors 11a, 11b, and 11c are stored. Arbitrary forms can be adopted for the orientation and arrangement of the accommodation holes 56, but the depth of the accommodation holes 56 is such that at least a part of the front surface of the module detectors 11a, 11b, 11c to be accommodated is exposed. It is desirable that it is. This is because the grip 54 grips the side surface of the housing 26 when the handling mechanism 53 transports the module detection units 11a, 11b, and 11c.
Here, processing in the radiation imaging apparatus 51 will be described focusing on automatic assembly of the detector 6.
First, the radiation imaging apparatus 51 acquires imaging parameters input from the operator console 10 by a doctor or an X-ray imaging engineer (step S1 in FIG. 9), and the types of module detection units 11a, 11b, and 11c based on the imaging parameters. The imaging conditions such as the number, the arrangement, and the like are automatically determined and displayed on the display device 9 (step S2). If the imaging conditions are approved by a doctor or an X-ray imaging engineer after manual correction of imaging conditions (step S4) is performed as necessary (YES in step S3), a control signal is output from the processing device 8 and imaging is performed. Preparation is started (step S5).
In preparation for imaging, automatic setup of the detector 6 by the handling mechanism 53 is performed prior to the movement of the detector 6 and the lighting of the lamp. That is, the processing device 8 handles the module detection unit 11 from the type and the arrangement of the module detection unit 11 obtained from the imaging conditions approved in step S3 and the positions of the module detection units 11a, 11b, and 11c registered in advance. A control signal is output to the mechanism 53. The handling mechanism 53 that has received the control signal grips the corresponding module detectors 11a, 11b, and 11c and conveys the hand 54 from the module trays 52a, 52b, and 52c to a predetermined position of the holder 12. For example, when the module detector 11a is mounted on the holder 12, the traveling carriage or manipulator 55 is moved to the position of the module detector 11a accommodated in the module tray 52a. In this state, the manipulator 55 is advanced toward the module tray 52a with the hand 54 opened. When the hand 54 is closed and the side surface of the housing 26 (see FIG. 2) of the module detection unit 11a is gripped, the manipulator 55 is retracted from the module tray 52a and then slid toward the holder 12. Thereafter, the height of the manipulator 55 is adjusted, and then the module detection unit 11 a is attached to a predetermined position of the holder 12. When the mounting is completed, the hand 54 is returned to the module tray 52a again, and the above processing is repeated until all the necessary module detection units 11a are mounted on the holder 12.
When the automatic setup of the detector 6 and other imaging preparations are completed, imaging is performed (step S6). The charges generated by the detection element 21 of the module detection unit 11 in response to the incidence of radiation are processed by the processing device 8 and displayed on the display device 9 as an image of the imaging region. When a necessary image is obtained, the imaging is finished (step S7). Note that the assembly process of the detector 6 receives the input of imaging parameters, determines the type, number and arrangement of the detector modules 11a, 11b, and 11c, and automatically handles the detector modules 11a, 11b, and 11c by the handling mechanism 53. It is a process including arranging 11c on the holder 12.
By providing the module trays 52a, 52b, 52c and the handling mechanism 53, such a radiation imaging apparatus 51 can automatically assemble the optimum detector 6 based on the imaging conditions. This makes it possible to quickly and easily set an optimal imaging device for the patient's imaging region. Furthermore, the burden on doctors and imaging technicians who perform imaging can be greatly reduced, and imaging efficiency can be greatly improved. Further, if the X-ray generator shown in FIG. 1 is added to the radiation imaging apparatus 51 to construct a radiation imaging system, X-ray imaging can be performed efficiently.
(Third embodiment)
A third embodiment of the present invention will be described in detail with reference to the drawings. In addition, about the same component as said 1st, 2nd embodiment, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.
The present embodiment relates to a module detection unit that can be easily two-dimensionally arranged.
11 is a perspective view, and FIG. 12 is an arrangement state of the module detection unit 61. The detection element 21, the readout circuit 22, and the information controller 23 as shown in FIG. have. The housing 66 has a clamp convex portion 71 for forming a fitting state with the other module detecting portion 61, and a clamp concave portion 72 that can be engaged with the clamp convex portion 71 of the same shape on the opposite surface. In addition, the clamp convex portion 71 and the clamp concave portion 72 are also provided at positions that are 90 degrees out of phase with respect to the clamp convex portion 71 and the clamp concave portion 72, respectively. The clamp convex portion 71 has a flange portion 74 having a diameter larger than that of the shaft portion 73. The clamp recess 72 is formed from a groove that penetrates the cable 24 on the take-out side. The groove has a width substantially equal to the diameter of the flange portion 74 of the clamp convex portion 71 in the inside thereof.
The two-dimensional arrangement of the module detectors 61 including the clamp protrusions 71 and the clamp recesses 72 is, for example, the clamp protrusions 71 of the module detector 61a located in the middle of the left column in FIG. The clamp recess 72 of the module detection unit 61a is fitted with the clamp projections 71 of the adjacent horizontal module detection unit 61c and the lower module detection unit 61d. Yes. Since the module detection units 61 are connected by fitting, the arrangement of the module detection units 61 is facilitated, and the relative displacement of the module detection units 61 can be prevented. Note that a band 63 may be wound around the outer periphery of the module detection unit group 62 in order to more firmly fix the module detection unit group 62, which is an assembly of the module detection units 61 combined in an arbitrary shape. The band 63 preferably has a hook-and-loop fastener and the like, and has a configuration that allows easy adjustment of the length and attachment / detachment.
The module detection unit 61 combined in this way receives voltage supply from the processing device 8 as shown in FIG. 1, and generates an electrical signal for each radiation incident position. The result of image processing performed by the processing device 8 that collects the electrical signals is output to the display device 9. Further, the combination which is the number and arrangement of the module detection units 61 is determined by the imaging parameters input from the operation console 10, or the combination of the module detection units 61 is automatically performed by the handling mechanism 53 shown in FIG. Or may be configured.
The present invention can be widely applied without being limited to the above-described embodiments.
For example, in each of the embodiments, the module detection units 11 and 61 using the semiconductor element 21a are described. However, other detection methods such as using an ionization chamber instead of the semiconductor element 21a have the same purpose. The effect can be exhibited similarly.
Also in the first embodiment, module detection units 11a, 11b, and 11c having a plurality of types of detection element thicknesses may be provided and stored in the plurality of module trays 52a, 52b, and 52c. Since the optimum detector 6 corresponding to the energy of the radiation can be formed, the exposure amount of the patient can be minimized and a clearer image can be obtained. Moreover, the module detection part 61 of 3rd embodiment can also be used for 1st, 2nd embodiment.
Furthermore, if the module trays 52a, 52b, and 52c are provided with lighting means such as display lamps one by one so that the module detectors 11a, 11b, and 11c indicated by the imaging conditions can be visually confirmed, they are reliably detected during manual operation. The container 6 can be assembled. Similarly, when lighting means that can visually confirm the arrangement of the module detectors 11 determined by the imaging conditions is provided for each arrangement position of the module detectors 11 in the holder 12, the detector 6 can be reliably assembled during manual operation. Is possible.
As described above, according to the present invention, it is possible to perform optimal radiation imaging corresponding to the body shape, imaging region, target radiation source, and time from RI administration of the imaging subject (patient, subject). The automatic imaging system that reduces the exposure of the patient can be easily realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a radiation imaging system in an embodiment of the present invention.
FIG. 2 is a conceptual diagram when the radiation imaging apparatus is used as an X-ray imaging apparatus.
FIG. 3 is a block diagram of the module detection unit.
FIG. 4 is a view taken along the line AA in FIG.
FIG. 5 is a schematic diagram for explaining the arrangement of the image to be imaged and the module detection unit.
FIG. 6 is a diagram showing the main medical radiation sources used in nuclear medicine.
FIG. 7 is a diagram showing the relationship between the thickness of the detection element and the amount of absorbed radiation.
FIG. 8 is a (a) side view and (b) front view showing the structure of the holder.
FIG. 9 is a flowchart of imaging processing in the radiation imaging system.
FIG. 10 is a diagram showing the configuration of the radiation imaging apparatus in the embodiment of the present invention.
FIG. 11 is a perspective view of the module detection unit.
FIG. 12 is a diagram showing an arrangement state of the module detection units shown in FIG.

Claims (10)

A detector for detecting radiation transmitted through an imaging target and / or radiation emitted from the imaging target, a processing device for performing image processing based on an electrical signal output from the detector, and obtained by image processing A radiation imaging apparatus including output means for outputting an image,
The detector is formed so that a detection module including a detection element that generates an electric charge upon incidence of the radiation can be arranged according to the imaging target, and includes a holding tool for holding the arrangement of the detection module,
An input device for inputting an imaging region of the imaging target as an imaging parameter is provided, and the processing device includes a database about the imaging parameter and the arrangement of the detection modules, and selects the arrangement of the detection modules based on the imaging parameters A radiation imaging apparatus characterized by being configured to do so.   2. The radiation imaging apparatus according to claim 1, wherein the detection element is configured using a compound semiconductor of CdTe, CZT, or GaAs, or a Si semiconductor.   2. The radiation imaging apparatus according to claim 1, wherein the detection elements of the adjacent detection modules are arranged so that an interval therebetween is 2 mm or less.   The radiation imaging apparatus according to claim 1, further comprising: a module tray that houses a plurality of the detection modules; and a handling mechanism that conveys the detection modules to the holder according to an arrangement selected based on the imaging parameters.   A radiation imaging system comprising: the radiation imaging apparatus according to claim 1; and an X-ray generation device as the radiation source, wherein the X-ray generation device is controlled by an output signal from the processing device. .   The radiation imaging apparatus according to claim 1, wherein the number of the detection modules forming the detector is determined based on a size of the imaging target.   The radiation imaging apparatus according to claim 1, wherein the detection modules having different detection surface thicknesses are selected according to the magnitude of the radiation energy.   The radiation imaging apparatus according to claim 1, wherein the detection module has a convex portion for engaging with another adjacent detection module and a concave portion that can be engaged with the convex portion of another detection module. A detector used for radiation imaging that detects radiation transmitted through the imaging object and / or radiation emitted from the imaging object to generate an image of the imaging object,
A detection module including a detection element that generates an electric charge upon incidence of the radiation; and a holder that holds the detection modules in a plurality of arrangements. The holder includes a plate that contacts the detection module; and the detection module. And a slot for positioning by sliding along the plate, wherein the slot is formed in the plate along the arrangement direction of the detection modules. A detector for detecting radiation transmitted through an imaging target and / or radiation emitted from the imaging target, a processing device for performing image processing based on an electrical signal output from the detector, and obtained by image processing Output means for outputting an image,
The detector is formed so that a detection module including a detection element that generates an electric charge upon incidence of the radiation can be arranged according to the imaging target, and includes a holding tool for holding the arrangement of the detection modules. An imaging support method in an imaging apparatus,
The radiation imaging apparatus includes an imaging Target an imaging parameter, a two dimensional array of the detection module, a database that associates,
The radiation imaging apparatus via the input device, when the imaging Target is input as an imaging parameter,
By searching the database as a search key imaging parameter input, the imaging support method characterized by determining a two-dimensional array of detection modules corresponding to the imaging Target on the display device.

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