JP3987141B2 - Nuclear medicine diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nuclear medicine diagnostic apparatus that detects gamma rays emitted from a radioisotope administered to a subject and images the in-vivo distribution of the radioisotope.
[0002]
[Prior art]
The nuclear medicine diagnostic device uses a single photon nuclide to detect one gamma ray at the time of decay of a radioisotope, and to obtain a two-dimensional gamma ray accumulation image based on this detection data. And a positron nuclide that emits a pair of gamma rays in the opposite direction when positrons annihilate, and a two-dimensional gamma ray accumulation image is obtained by specifying the emission location. It is classified as TRON camera.
[0003]
In recent years, a tomographic technique (ECT (emission computed tomography)) that detects gamma rays at a plurality of angles and reconstructs a tomographic image based on the detected gamma rays has been put into practical use. This ECT is roughly classified into single photon ECT (SPECT) and positron ECT (PET).
[0004]
In conventional scintillation, photomultiplier tubes are two-dimensionally and closely arranged on a scintillator (NaI single crystal) that gives gamma rays to light through a light guide, as represented by an Anger-type camera. The location where the gamma rays were generated was obtained from the output signal by weight addition calculation. Since the photomultiplier tube is used as the photoelectric conversion element in this way, the detector has an extremely thick ellipse, and the outermost peripheral portion of the photomultiplier tube cannot be subjected to position calculation. Space is generated, and the detector has a very large area for the effective field of view. If the lead shield on the periphery or back is inserted into the collimator, it becomes a very large detector, and even if this detector is set according to the collection purpose, control is added and the operation is realized. Since the means is extremely difficult mechanically and the detector is as heavy as several hundred kg, image degradation due to mechanical distortion may occur from an ideal operation. In addition, because the distance from the effective field edge to the embedded surface of the detector is large, and the detector is thick, it is necessary to raise the arm greatly to the head side during cardiac SPECT, which may cause pain to the examiner. There was a problem that the cerebellum did not enter in the head SPECT.
[0005]
Conventionally, when performing SPECT of the heart, in order to avoid interference with a very large anger-type detector, the subject raises both arms to the head side during the data collection period, for example, for 10 minutes or more. It was necessary to continue, and it was very painful for the subject.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a nuclear medicine diagnostic apparatus capable of reducing the size and weight of a detector and thereby improving the degree of freedom of collection.
Another object of the present invention is to provide a nuclear medicine diagnostic apparatus capable of collecting SPECT data without causing great pain to the subject during cardiac SPECT.
[0007]
[Means for Solving the Problems]
  The present inventionFirst aspect ofIsA detector having a plurality of two-dimensionally arranged semiconductor elements for directly converting gamma rays emitted from a radioisotope administered to a subject into an electrical signal, and based on the output of the detector An image generator for generating an image of the distribution of the radioisotope in the body, a rotation mechanism for rotating the detector around the subject, a rotation axis of the detector, and a center of the detector from the rotation axis An orthogonal axis moving mechanism that moves the detector along an orthogonal axis that is orthogonal to a radial axis that is directed to, a rotational axis moving mechanism that moves the detector along the rotational axis of the detector, and the radial axis. A radial axis moving mechanism that moves the detector along the radial axis, a radial axis rotating mechanism that rotates the detector around the radial axis, a rotational motion in which the detector rotates twice around the subject, Detector detects the gamma rays When collecting data necessary for SPECT of the subject by synchronizing with a unit operation for collecting data necessary for image generation continuously for a predetermined time, one of two rotations of the detector is rotated. And a control unit that controls the orthogonal axis moving mechanism so that the positions of the detectors with respect to the orthogonal axis are different between the circumference and the second circumference.
  According to a second aspect of the present invention, there is provided a detector having a plurality of two-dimensionally arranged semiconductor elements for directly converting gamma rays emitted from a radioisotope administered to a subject into an electrical signal; An image generation unit that generates an image of the in-vivo distribution of the radioisotope based on the output of the detector, a rotation mechanism that rotates the detector around the subject, a rotation axis of the detector, and the An orthogonal axis moving mechanism that moves the detector along an orthogonal axis that is orthogonal to a radial axis from the rotation axis toward the center of the detector, and a rotation axis that moves the detector along the rotation axis of the detector A moving mechanism; a radial axis moving mechanism that moves the detector along the radial axis; a radial axis rotating mechanism that rotates the detector around the radial axis; and an intermittent state of the detector around the subject. Rotational movement and the rotation axis When the center of the collection target site in the subject is deviated, the detector performs detection of the gamma rays for a predetermined time in synchronization with a unit operation for collecting data necessary for image generation, When collecting data necessary for SPECT of the collection target portion, the orthogonality is obtained at each rotation angle so that the collection target portion is included in the field of view of the detector at each rotation angle around the subject. And a controller for controlling the orthogonal axis moving mechanism to adjust the position of the detector with respect to the axis.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a nuclear medicine diagnosis apparatus according to the present invention will be described with reference to the drawings. The nuclear medicine diagnostic apparatus of the present invention uses a single photon nuclide to detect one gamma ray at the time of decay of a radioisotope and to obtain a two-dimensional gamma ray accumulation image based on this detection data. Using a camera (scintillation camera) and a positron nuclide to emit a pair of gamma rays in the opposite direction when the positron annihilates, and to obtain a two-dimensional accumulated image of gamma rays by specifying the emission location The featured positron camera, gamma rays from a single photon nuclide are detected from multiple angles around the subject, and single photon ECT (SPECT) that reconstructs a tomographic image based on the detected gamma rays from the subject. Positron ECT that detects from multiple angles around the image and reconstructs a tomogram based on it It may be any of PET). Here, a type capable of using both a single photon camera (scintillation camera) and SPECT will be described as an example.
(First embodiment)
FIG. 1 shows a block diagram of the nuclear medicine diagnostic apparatus according to the present embodiment. The detector 11 is a parallel porous collimator 13, a semiconductor element array 15 in which a plurality of semiconductor elements that directly convert gamma rays into electrical signals are arranged vertically and horizontally, and amplifies the output of each of the plurality of semiconductor elements individually. And a preamplifier array 17.
[0013]
Based on the output of the preamplifier array 17, the image generation processor 19 generates the in-vivo distribution of the radioisotope administered to the subject as a so-called static image. Further, at the time of SPECT acquisition, the image generation processor 19 reconstructs the in-vivo distribution of the radioisotope relating to the cross section of the subject as a tomographic image based on the output of the preamplifier array 17. These image data are displayed on the display 21.
[0014]
The stand 23 supports the detector 11. The stand travel mechanism 25 is configured so that the stand 23 can be electrically driven according to the control signal of the movable part controller 35, and is realized by a rotary encoder or the like for feeding back the position of the stand 23 to the movable part controller 35. It has a position detection function that can be performed. The stand travel mechanism 25
The detector revolution mechanism 27 is configured to be able to rotate (revolve) the detector 11 around the subject in accordance with a control signal from the movable part controller 35, and to cause the movable part controller 35 to revolutionize the detector 11. In order to feed back the angle, a revolution angle detection function that can be realized by a rotary encoder or the like is provided. For convenience of explanation, the rotation (revolution) center of the center point of the detection surface of the detector 11 is the origin, the rotation axis of revolution is the X axis, and the radial direction of revolution passing from the origin to the center point of the detection surface is the Z axis. Then, a moving coordinate system with the Y axis is defined so as to be orthogonal to the XZ axis.
[0015]
The detector moving mechanism 29 is configured to be able to translate the detector 11 by a relatively small distance individually with respect to each of the three axes XYZ orthogonal according to the control signal of the movable part controller 35, and the movable part. The controller 35 has a position detection function that can be realized by a rotary encoder or the like in order to feed back the position of the detector 11 with respect to each of the three XYZ orthogonal axes. The detector rotation mechanism 31 is configured to be able to electrically rotate (spin) the detector 11 with respect to a rotation axis parallel to the Z axis in accordance with a control signal of the movable unit controller 35, and to the movable unit controller 35. In order to feed back the rotation angle of the detector 11, it has a rotation angle detection function that can be realized by a rotary encoder or the like.
[0016]
The bed 33 supports the subject in a supine state, for example, so that the body axis of the subject coincides with or substantially parallel to the Z axis.
The movable part controller 35 individually controls the stand travel mechanism 25, the detector revolution mechanism 27, the detector movement mechanism 29, and the detector rotation mechanism 31 in accordance with an operator command input via the console 37. Further, the movable part controller 35 controls the relative movements of the stand travel mechanism 25, the detector revolution mechanism 27, the detector moving mechanism 29, and the detector rotation mechanism 31 that are required during whole body collection or SPECT collection.
[0017]
FIG. 2 shows an appearance of the detector 11 of FIG. The semiconductor element array 15 has an energy resolution superior to that of a conventional indirect detection method combined with a scintillating photomultiplier tube. For example, a plurality of semiconductor elements such as CdZnTe having an outer dimension of 3 mm × 3 mm × 5 mm are 15 cm long. It is two-dimensionally arranged in a rectangle of ˜30 cm and a width of 20 cm to 50 cm. This rectangular size is determined as an optimal size that avoids the abundant use of relatively expensive semiconductor elements that contain the heart and head in the field of view of the detector 11 (vertical 15 cm to 30 cm x horizontal 20 cm to 50 cm). Has been. Although not shown, in order to avoid erroneous detection due to the incidence of gamma rays from the side surfaces and the back surface, a shield layer such as lead that does not transmit gamma rays is formed on the side surfaces and the back surface of the semiconductor element array 15 and the preamplifier array 17. Yes.
[0018]
FIG. 3A shows a front view of a detector system including the detector 11, the bed 31, the stand 23, and the like, and FIG. 3B shows a side view of the detector system. The stand 25 includes two support columns 39 and a stand base 41. The stand travel mechanism 25 has a structure in which a recess 43 formed on the bottom surface of the stand base 41 is movably fitted to a travel rail 45 provided on the floor, a travel drive motor, and a power transmission system. The detector revolution mechanism 27 includes a structure in which a rotating ring 49 is rotatably provided on a fixed ring 47 fixed to a support column 39 of a stand 25, a driving motor 51, and a driving gear provided on a driving shaft of the driving motor 51. 53 and a power transmission system including a timing belt 55 stretched over the drive gear 53 and the rotating ring 49.
[0019]
A support arm 59 that supports the detector 11 is slidably inserted into the cylindrical member 57 fixed to the rotating ring 49. With this structure, the detector 11 can be moved with respect to the Z axis, that is, detected with respect to the subject. The container 11 can be approached / separated (see FIG. 4B). As shown in FIG. 4A, one end of the support arm 59 is slidably and rotatably fitted in an X guide groove 61 and a Y guide groove 63 formed on the back surface of the detector 11, and this structure allows XY The detector 11 can move with respect to the shaft and can rotate.
[0020]
Although not shown, the electrical connection between the detector 11 and the image generation processor 19 is realized by a slip ring mechanism.
Next, a static image collection operation will be described. As described above, the detector 11 is configured with a relatively small visual field that allows the head and the heart to enter. Therefore, when collecting a comparatively large target part that does not fit in the visual field, a device is required for the collection procedure.
[0021]
FIG. 5A shows a procedure at the time of chest collection. In this case, the movement of the detector 11 in the X or Y direction and the unit of gamma rays by the detector 11 are controlled by the movable controller 35. The detection operation is performed in synchronization. Note that an operation in which the detector 11 continues the detection of gamma rays for a predetermined time and collects data necessary for image generation is defined as “one unit detection operation.” First, the detector 11 is defined as (A ) At a position for a predetermined time, during which gamma ray detection is continued, and then the detector 11 is moved to the position (B) and stopped at this position for a predetermined time, during which gamma ray detection is continued. In this way, a collection procedure in which the detector 11 is translated and the detection operation of one unit is repeated twice is defined as a two-step operation.
[0022]
Further, as shown in FIG. 5B, it is possible to rotate and collect the detector 11 according to the shape of the target region.
FIG. 6 shows a whole body collection procedure. In whole body collection, one unit of detection operation is repeated in the order represented by (1) to (n), that is, the detector 11 is set to have a predetermined time required for one unit of detection operation in the X direction (body axis direction). It moves intermittently as a cycle, and in synchronization with this, the detection operation of one unit of gamma rays by the detector 11 is repeated. Further, the two-step operation shown in FIG. 5A is used in combination on the chest, the trunk, and the like where the width of the subject P is longer than the field of view of the detector 11. Further, the two-step operation is not used together in a portion including the head and the tip of the foot where the width of the subject P is shorter than the visual field of the detector 11. By such a procedure, whole body collection can be performed efficiently.
[0023]
When considering the closest approach trajectory collection, the small-field-weight and light-weight detector 11 of this embodiment is compared with the subject P as compared with a large-field weight detector that combines a conventional scintillator and a photomultiplier tube. It can be made to approach 25 mm or more. By designing so that the sensitivity of the collimator 13 is improved as much as the resolution is improved, the system sensitivity can be designed to be about 3 times per unit area as compared with the conventional system while having a small field of view. . In addition, the energy resolution of the detector 11 by the semi-conductive element of the present embodiment is far superior to a large-field detector that combines a conventional scintillator and a photomultiplier tube (^99m(Tc is the target of about 5% energy resolution compared to the conventional energy resolution of about 10%). Therefore, the whole body image with the same count number has high contrast in the same acquisition time as the conventional large-field detector. Can be collected with resolution.
[0024]
Next, the SPECT collection operation will be described. The detector 11 revolves intermittently at a constant angle, and one unit of detection operation by the detector 11 is repeated in synchronization with this, whereby data necessary for SPECT of the subject can be collected. Similarly, the SPECT collection requires a device for the collection procedure.
[0025]
As shown in FIG. 7, in synchronization with the intermittent revolution motion of the detector 11, detection is performed by reciprocating the detector 11 in the Y direction (two-step operation) while the revolution motion is stopped. The small field of view of the vessel 11 can be compensated.
[0026]
FIG. 8A shows the position in the Y direction of the detector 11 at the time of SPECT acquisition in the first round, and FIG. 8B shows the position in the Y direction of the detector 11 at the time of SPECT acquisition in the second round. Yes. In order to compensate for the small field of view of the detector 11, at least two rounds of SPECT acquisition may be performed. In this case, the positions in the Y direction are made different between the first and second rounds so that the fields of view of the detector 11 do not overlap between the first and second rounds. The method of FIG. 8 is simpler than that of FIG. 7, and the number of times the detector 11 is moved in the Y direction is small, and the collection time can be shortened by the time required for this movement. In addition to collecting for intermittent revolving motion, it is also possible to deal with continuous revolving motion.
[0027]
FIG. 9 shows a collection procedure when the center of revolution and the center of the target part such as the heart are deviated. In such a case, the detector 11 is moved by an appropriate distance in the Y direction for each angle of the revolution movement so that the target part enters the field of view at each angle of the revolution movement of the detector 11. Adjust.
[0028]
Of course, in the system of FIG. 3, for example, the detector 11 having an effective field of view of about 25 cm long and 50 cm wide can be used to obtain a SPECT image without moving in the Y direction. Needless to say, it can be obtained by a single scan.
[0029]
The present embodiment can be modified as follows.
As shown in FIGS. 10A and 10B, the rotary ring 49 is rotatably supported by the fall-prevented driven wheel 61, and the rotary ring 49 is directly driven to rotate by the drive gear 53. Also good.
[0030]
Further, as shown in FIG. 11, a mobile carriage 63 on which the detector system can be mounted from the stand base 41 enables movement to an examination room or an emergency medical room in a hospital. 65, a handle 67, and a caster 69. The caster 69 is provided at the bottom of the carriage main body 65 so as to be vertically movable so that the caster 69 can be lowered during movement and raised during installation to fix the carriage main body 65 to the floor surface.
[0031]
As shown in FIGS. 12 and 13, a detector system having the same configuration as that shown in FIGS. 1 to 3 may be configured as a two-detector type nuclear medicine diagnostic apparatus provided with two systems. The first detector system 101-1 has the same first components 11-1 to 59-1 as shown in FIGS. 1 to 3, and the second detector system 101-2 is also shown in FIGS. 2 has the same second components 11-2 to 59-2 as shown in FIG. The second detector system 101-2 is inverted 180 ° and installed on a traveling rail 45 common to the first detector system 101-1.
[0032]
By providing two detector systems in this way, the following collection operation is realized. With the positional relationship between the first detector 11-1 of the first detector system 101-1 and the second detector 11-2 of the second detector system 101-2 maintained at 90 °, By revolving around the subject P, the so-called 90 ° SPECT collection of the subject P can be performed jointly by both parties. In addition, collection at an angle other than 90 ° can be performed without any problem. In addition, the first detector 11-1 and the second detector 11-2 are revolved around the subject P in a state where the first detector 11-1 and the second detector 11-2 are opposed to each other with the subject P interposed therebetween. By collecting the subject P (7) SPECT, the collection of data necessary for SPECT can be completed by revolution of about half a circle.
[0033]
Further, as shown in FIG. 14, the first detector 11-1 detects gamma rays from the first part (eg, heart) of the subject P, and based on the output of the first detector 11-1. The image generation processor 19 generates a first distribution in the body, and the second detector 11-2 detects gamma rays from the second part (for example, the head) of the subject P to detect the second detector 11. Based on the output of -2, the second biodistribution of the image generation processor 19 can be generated, and thus static collection can be performed at two locations simultaneously. Similarly, SPECT collection can be performed at two locations simultaneously. Further, the first detector 11-1 and the second detector 11-2 can collect data with different collection conditions.
[0034]
As shown in FIG. 14, the arm rest 63 for placing the arm on the subject P is placed in the direction intersecting the body axis of the subject P (for example, an angle of about 90 ° with respect to the body axis). The bed 33 is provided so as to be able to support it stably, and it is possible to reduce the burden of the test holiday P at the time of simultaneous collection of the heart and the head, which could not be done conventionally. Moreover, even if only the heart collection is considered, conventionally, the large anger type detector and the arm interfere with each other, so it was impossible to collect unless the arm was raised greatly. Collecting can be done.
[0035]
  As described above, this embodiment can obtain the following effects by using a small-field detector using a semi-conducting element.
(1) Since the system sensitivity of the semiconductor detector is significantly higher than that of a detector combining a conventional scintillator and a photomultiplier tube, the SPECT collection time of the heart and head can be reduced to less than half of the conventional time. The energy resolution is good and the contrast resolution of the image is high due to the low mixing rate of scattered radiation in the window of interest.
(2) Collection that has been possible in the past, such as whole body SPECT, whole body collection, and static collection, can be performed in the same or longer collection time, and the contrast resolution of the image is high.
(3) When two detector systems are considered, SPECT or Stattic can be collected simultaneously at two different locations in the body axis direction such as the heart and head, which was impossible in the past. Can be collected at.
(4) The 90 SPECT of the heart can be collected easily and in less than 1/2 time.
(5) The upgrade from the 1 detector system to the 2 detector system can be easily realized.
(6) Since it is as short as 1 cm or less from the effective visual field end of the semiconductor detector to the shield end, mammo scinching is possible while sitting on a desk.
(7) It can be moved to another examination room by a mobile cart.
(8) Transmission CT can be realized easily and with high image quality with a two-detector system.
(9) Since the opening diameter of the entire rotating ring can be designed to be large and there is no overall intimidation, the subject's sense of security is great.
(10) Since the weight of the collimator can be reduced to about 10 kg to 20 kg, it can be attached by hand.
(11) In the two-system detector system, the semiconductor detector has an excellent count processing capacity of 500 kcps or more. It can also be used for coin detection of FDG-PET.
(Second Embodiment) FIG. 15 shows the configuration of the main part of a nuclear medicine diagnostic apparatus according to a second embodiment. The configuration of the nuclear medicine diagnosis apparatus according to the second embodiment is different from that of the first embodiment in the following points. The nuclear medicine diagnostic apparatus according to the second embodiment does not employ an anger-type detector, and two semiconductor detectors 1221, 1222, which are smaller, thinner and lighter than the anger-type detector, are connected from a stand 133 via arms 1391, 1392. Thus, a configuration in which the object P is supported in a state of being opposed to each other is adopted. In such semiconductor detectors 1221, 1222, the subject P required at the time of cardiac imaging using an anger-type detector needs to take a posture with a large burden with both arms greatly raised to the head side. For example, a relatively easy posture in which both arms are opened at an angle θ of 45 ° or more and 90 ° at the maximum with respect to the trunk (body axis) is possible.
[0036]
In order to further ease this posture, an armrest 140 is used. The armrest 140 is configured so that the subject P can limit the opening angle θ between each arm and the body axis to a specific angle of at least 45 ° or more, for example, an acrylic material or a carbon material in a bow shape. Molded. A magic fastener 141 is provided at the central portion of the armrest 140 so that the armrest 140 is mounted so as not to move to an arbitrary position on the top plate 137 and can be detached from the top plate 37 when not in use.
[0037]
The arm resting portion 142 of the armrest 140 is formed in a substantially U-shaped cross section (or a substantially U-shaped cross section or a substantially L-shaped cross section) opened upward, and the arm is detached from the armrest 140, moves, or the arm is closed. In particular, it is possible to reliably prevent interference between the arm and the detectors 1221, 1222, especially during SPECT imaging in which the detectors 1221, 1222 rotate around the subject P.
[0038]
Conventionally, the thickness of the anger-type detector and the distance from the end of the effective field of view to the outer end face of the shield (dead space) are as large as 5 cm or more. As long as the head side is necessary, the semiconductor detectors 1221 and 1222 can be designed to be very thin and can be designed with a thickness of about 5 cm to 10 cm including the collimator portion. Since the position of the semiconductor element can be detected as it is, all the two-dimensionally arranged surfaces of the semiconductor element can be used as an effective field, and the distance from the effective field edge to the shield outer edge is substantially the thickness of the shield. The length can be reduced to about 5 mm to 15 mm, which is significantly smaller than the conventional one. Therefore, the posture as described above is possible.
[0039]
Thus, by using the armrest 140 of this embodiment in combination with the semiconductor detectors 1221, 1222, the pain of the subject P is greatly reduced, and thus the subject P moves the body during the collection period. The possibility of image degradation due to is reduced.
[0040]
In addition, as shown in FIG. 16, this armrest may be constructed such that the rest main bodies 1441, 1442 on which the arm is placed are supported by the stands 1431, 1432 instead of being mounted on the top plate.
The present invention is not limited to the above-described embodiments, and can be implemented with various modifications.
[0041]
【The invention's effect】
  According to the present invention, the detector can be reduced in size and weight, thereby improving the degree of freedom. Further, the whole body can be collected with a small detector by moving the detector along an orthogonal axis orthogonal to a rotation axis of the detector and a radial axis from the rotation axis toward the center of the detector.
[Brief description of the drawings]
FIG. 1 is a block diagram of a nuclear medicine diagnostic apparatus according to a first embodiment of the present invention.
2 is an external view of the detector of FIG. 1. FIG.
FIG. 3 is a front view and a side view of the detector system of the present embodiment.
4 is a view showing a detector moving mechanism in FIG. 1; FIG.
FIG. 5 is an explanatory diagram of a procedure for collecting a chest, a head, and a heart according to the present embodiment.
FIG. 6 is an explanatory diagram of a whole body collection procedure according to the present embodiment.
FIG. 7 is an explanatory diagram of a SPECT collection procedure according to the present embodiment.
FIG. 8 is an explanatory diagram of another SPECT collection procedure according to this embodiment.
FIG. 9 is an explanatory diagram of a SPECT collection procedure when the center of revolution and the center of a target part such as a heart are deviated according to the present embodiment.
10 is a diagram showing another configuration example of the detector revolution mechanism of FIG. 1. FIG.
FIG. 11 shows a mobile trolley for moving the detector system.
FIG. 12 is a block diagram of a nuclear medicine diagnostic apparatus having two detector systems as a modified train of the present embodiment.
13 is a side view of the system of FIG.
FIG. 14 is a diagram showing a state of simultaneous collection at two locations by the system of FIG.
FIG. 15 is a diagram showing an armrest according to a second embodiment.
16 is a view showing a modification of FIG.
[Explanation of symbols]
11 ... detector,
13 ... Collimator,
15 ... Semiconductor element array,
17 ... Preamplifier array,
19 ... Image generation processor,
21 ... Display,
23 ... Stand,
25 ... Stand traveling machine Oval,
27 ... Detector revolution mechanism,
29 ... Detector moving mechanism,
31 ... Detector rotation mechanism,
33 ... Sleeper,
35 ... movable part controller,
37 ... Console.

Claims (6)

A detector having a plurality of two-dimensionally arranged semiconductor elements for directly converting gamma rays emitted from a radioisotope administered to a subject into an electrical signal;
An image generation unit that generates an image of the in-vivo distribution of the radioisotope based on the output of the detector;
A rotation mechanism for rotating the detector around the subject;
An orthogonal axis moving mechanism for moving the detector along an orthogonal axis orthogonal to a rotation axis of the detector and a radial axis from the rotation axis toward the center of the detector;
A rotation axis moving mechanism for moving the detector along the rotation axis of the detector;
A radial axis moving mechanism for moving the detector along the radial axis;
A radial axis rotation mechanism for rotating the detector about the radial axis;
Synchronously performing a rotational movement in which the detector rotates twice around the subject and a unit operation in which the detector continuously detects the gamma rays for a predetermined time and collects data necessary for image generation. Thus, when collecting data necessary for SPECT of the subject, the position of the detector with respect to the orthogonal axis is different between the first and second rounds of the two rounds of rotation of the detector. radiological imaging apparatus you characterized by comprising a controller for controlling the orthogonal axis moving mechanism. A detector having a plurality of two-dimensionally arranged semiconductor elements for directly converting gamma rays emitted from a radioisotope administered to a subject into an electrical signal;
An image generation unit that generates an image of the in-vivo distribution of the radioisotope based on the output of the detector;
A rotation mechanism for rotating the detector around the subject;
An orthogonal axis moving mechanism for moving the detector along an orthogonal axis orthogonal to a rotation axis of the detector and a radial axis from the rotation axis toward the center of the detector;
A rotation axis moving mechanism for moving the detector along the rotation axis of the detector;
A radial axis moving mechanism for moving the detector along the radial axis;
A radial axis rotation mechanism for rotating the detector about the radial axis;
When the rotation axis and the center of the collection target site in the subject are deviated, intermittent rotation of the detector around the subject and the detector continues to detect the gamma ray for a predetermined time. The unit operation for collecting data necessary for image generation is performed in synchronization with each other to collect the data necessary for SPECT of the collection target site at each rotation angle around the subject. A control unit that controls the orthogonal axis moving mechanism to adjust the position of the detector with respect to the orthogonal axis at each rotation angle so that the target part is included in the field of view of the detector. nuclear medicine diagnostic apparatus shall be the feature. The semiconductor device, a nuclear medicine diagnostic apparatus according to claim 1 or 2, wherein the a CdZnTe. The subject comprises a bed having an armrest for placing an arm, and the armrest can stably support the arm in a direction intersecting with a body axis of the subject. The nuclear medicine diagnostic apparatus according to claim 1 or 2 . The detector stand for supporting a nuclear medicine diagnostic apparatus according to claim 1, wherein further comprising a carriage for mounting the stand. Wherein the plurality of semiconductor elements are nuclear medicine diagnostic apparatus according to claim 1 or 2, wherein the one side the other side within the 15cm~30cm are rectangular two-dimensionally arranged within a range of 20 to 50 centimeters.

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