JPH10160848A - Nuclear medicine diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cope with a diversified data collection mode flexibly by providing three semiconductor detectors rotatably around a subject and combining them properly. SOLUTION: First and second semiconductor detectors 2 and 3 are mounted on a first stand 1, a third semiconductor detector 7 is mounted on a second stand 8, and stand running mechanisms 6 and 10 are run in parallel with the long axis of each bed 14. The semiconductor detectors 2, 3, and 7 rotate respectively around a subject and gamma rays from dosed isotope are converted to an electrical signal. By combining the semiconductor detectors 2, 3 and 7 in various ways, it is made possible to cope with various data collection modes such as a static data collection mode, a SPECT data collection mode, a 2- detector opposition SPECT data collection mode, a 2-detector 90 deg. opposition SPECT data collection mode, and 3-detector SPECT data collection mode. Also, the semiconductor detector 3 can be made freely detachable and also can be upgraded later.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear medicine diagnostic apparatus for detecting gamma rays emitted from a radioisotope administered to a subject and imaging the distribution of the radioisotope in the body.

[0002]

2. Description of the Related Art A nuclear medicine diagnostic apparatus detects a single gamma ray when a radioisotope decays using a single photon nuclide, and obtains a two-dimensional gamma ray accumulated image based on the detected data. Using a single photon camera and emitting a pair of gamma rays in the opposite direction when the positron is annihilated using a positron nuclide,
It is classified into a positron camera characterized in that a two-dimensional gamma ray accumulated image is obtained by specifying an emission place.

In recent years, gamma rays have been repeatedly detected at a plurality of angles while rotating the detector around the subject, and a tomographic imaging technique (ECT (emission) for reconstructing a tomographic image based on the obtained data. compu
ted trophy)) has been commercialized.
This ETC is a single photon ECT (SPECT)
And positron ECT (PET).

In the conventional scintillation, a photomultiplier tube is two-dimensionally and densely arranged via a light guide on a scintillator (single crystal of NaI) which converts gamma rays into light as represented by an Anger type camera. The location of the gamma ray is calculated from each output signal by weight addition calculation. Since the photomultiplier tube is used as the photoelectric conversion element, the detector has an extremely thick structure, and a dead space in which the position cannot be calculated is located at the outermost periphery of the photomultiplier tube. Is generated, and the detector becomes an extremely large area for the effective visual field. When the lead shield and collimator on the periphery and back are inserted, it becomes a very large detector, and even if this detector is set according to the purpose of collection, control is added to the degree of freedom and the means for realizing the operation is Since it is extremely mechanically difficult and the detector is heavy with a weight of several hundred kg, image deterioration due to mechanical distortion may occur from ideal operation. In addition, since the distance from the effective visual field end to the physical end face of the detector is large, and the detector is thick, the cardiac SPEC is increased.
At the time of T, it is necessary to raise the arm greatly to the head side, and there is a problem that the subject is distressed and the cerebellum does not enter in the head SPECT.

There are various data collection (photographing) methods for nuclear medicine diagnosis as described below. (1) a one-detector static data collection method in which a single detector is directly opposed to a target site and data is collected in a stationary state to obtain a projected distribution (plane image) of a radioisotope;
(2) One detector SPEC that obtains a radioisotope distribution of a cross section like X-ray CT by repeating data collection at a plurality of angles while rotating a single detector around the subject once.
T data collection, (3) While two detectors are provided facing each other, data collection is repeated at a plurality of angles during one rotation around the subject to obtain a radioisotope distribution of the cross section. SPECT data collection, (4) Two detections in which two detectors are arranged at a 90 ° offset and the data collection is repeated at a plurality of angles during one rotation around the subject to obtain the radioisotope distribution of the cross section Vessel 90 ° SPECT
Data acquisition, (5) While the three detectors are provided in a state shifted by 120 ° and the circumference of the subject is rotated by ３,
3-detector SPECT data collection to obtain the radioisotope distribution of the cross section by repeating data collection at multiple angles.

Conventionally, the above-described various data collection methods cannot be shared by a single device, so that the data collection method has been limited, and it has been necessary to introduce a plurality of types of devices.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a nuclear medicine diagnostic apparatus which can flexibly cope with various data collections.

[0008]

A nuclear medicine diagnostic apparatus according to the present invention is provided with a first stand movably provided, and mounted on the first stand rotatably around a subject.
A first semiconductor detector that directly converts a gamma ray emitted from a radioisotope administered to the subject into an electric signal, and the first stand includes the first semiconductor detector and the first semiconductor detector. A second semiconductor detector that is rotatably mounted around and that directly converts the gamma ray into an electric signal; a second stand that is provided so as to be freely movable; and a second stand that surrounds the subject on the second stand. And a third semiconductor detector that is rotatably mounted and directly converts the gamma ray into an electric signal. (Operation) By appropriately combining and arranging the first to third semiconductor detectors, a static data collection mode, a SPECT data collection mode, and a two-detector SPE
Various data acquisition modes such as a CT data acquisition mode, a two-detector 90 ° SPECT data acquisition mode, and a three-detector SPECT data acquisition mode can be flexibly supported.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the nuclear medicine diagnostic apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of the nuclear medicine diagnostic apparatus according to the present embodiment, and FIG.
1 shows the appearance of the first, second and third semiconductor detectors in FIG. 1, FIG. 3 shows the first and second data collection systems in FIG. 1 viewed from the side, and FIG. FIG. 4B shows the structure of the first data collection system of FIG. 1 as viewed from the subject head side, and FIG. 4B shows the structure of the second data collection system of FIG. 1 as viewed from the subject head side. I have. In FIG. 1, the structural connection is shown by a dotted line, and the electrical connection is shown by a solid line. In the present embodiment, two physically separated data collection systems are provided.

In the first data collection system, two first semiconductor detectors 2 and two second semiconductor detectors 3 are mounted on a first stand 1. The first stand 1 is arranged on the floor so as to be able to travel in parallel with the long axis of the bed 1,
This traveling is realized by the stand traveling mechanism 6.
The stand traveling mechanism 6 is configured such that, for example, a bottom groove 38 of a stand frame 36 is fitted into a rail 37 provided on a floor surface, and the stand frame 36 is electrically driven via a rack and pinion mechanism.

As shown in FIG. 2, each of the first semiconductor detector 2 and the second semiconductor detector 3 includes a plurality of two-dimensional semiconductor elements such as CdZnTe for directly converting a gamma ray into an electric signal. An arrayed semiconductor element array 102;
A collimator 101 provided on the incident side of the semiconductor element array 102 for restricting an incident direction of gamma rays, a circuit board 103 provided on a back side of the semiconductor element array 102 on which a preamplifier, a readout circuit, and the like are mounted; Lead shield 104 that shields unnecessary gamma rays from
Consists of

The overall rotation mechanism 4 of the first data collection system
In order to rotate the first and second semiconductor detectors 2 and 3 around the subject P placed on the bed 14, for example, a rotating ring 32 rotatably provided on a fixed ring 31.
The first semiconductor detector 2 and the second semiconductor detector are attached to the motor, and the rotating ring 32 is configured to be rotationally driven by a motor 34 via a driving gear 35 and a driving belt 33.

The slide mechanism 5 includes the first semiconductor detector 2
In order to change the angle difference along the whole rotation direction between the second semiconductor detector 3 and the second semiconductor detector 3, the second semiconductor detector 3 is slid on the rotating ring 32 along the whole rotation direction, For example, a slide groove 39 is formed in the rotating ring 32, the second semiconductor detector 3 is slidably fitted in the slide groove 39, and the second semiconductor detector 3 is electrically driven to slide. I have.

The first semiconductor detector 2 and the second semiconductor detector 2 are controlled by the movable unit controller 11 as shown in FIG.
Angle difference between the semiconductor detectors of 90 °, 120 °, 180 ° according to the operator's instruction from the console 12.
It stops automatically at any of °.

The second semiconductor detector 3 is moved 90 degrees from the first semiconductor detector 2 by eliminating the slide mechanism 5.
It may be fixed to the rotating ring 32 with an angle difference of any of °, 120 °, and 180 °.

On the other hand, in the second data collection system, one third semiconductor detector 7 is mounted on the second stand 8. The structure of the third semiconductor detector 7 is the same as that of the first and second semiconductor detectors 2 and 3 as shown in FIG. The second stand 8 is disposed on the floor so as to be able to travel in parallel with the long axis of the bed 1.
0.

The whole rotation mechanism 9 of the second data collection system
Is similar to the overall rotation mechanism 4 of the first data collection system,
The third semiconductor detector 7 is configured to rotate around the subject P placed on the bed 14.

The image generation processor 13 includes first, second,
The number of gamma rays incident on each array surface is counted based on the outputs of the third semiconductor detectors 2, 3, and 7. Based on the count data, data specified by the operator via the console 12 is displayed. For example, a projection distribution (plane image) of a radioisotope administered to a subject according to an acquisition mode is generated for each detector, and one radioisotope distribution of a cross section of the subject or two for each data acquisition system Generate. The display 20 displays the distribution image generated by the image generation processor 19.

The movable unit controller 15 includes the console 1
In accordance with an instruction input by the operator via the control unit 2, the overall rotation mechanisms 4, 9, the slide mechanism 5, the stand traveling mechanism 6,
10 movements are controlled. (Operation) In the present embodiment, the three semiconductor detectors 2, 3, and 7 can be variously combined to correspond to, for example, the following various data collection modes. (1) The first and second semiconductor detectors 2 and 3 are made to face the same part, for example, the head from different directions, and the third semiconductor detector 7 is made to face the abdomen, for example. And a radiographic isotope projection distribution image (static image) viewed from one direction of the head, a radioisotope projection distribution image viewed from another direction of the head, and an abdominal direction And a radioisotope projection distribution image (static data collection mode). Of course, one or two images may be obtained by using one or two of the first to third semiconductor detectors 2, 3, and 7. (2) The first or second semiconductor detectors 2 and 3 and the third semiconductor detector 7 are respectively rotated around different parts, for example, around the head and abdomen. The data collection is repeated at an angle of, and a radioisotope distribution image (SPECT image) of the head section such as X-ray CT and a SPECT image of the abdomen section can be obtained (SPECT).
Data collection mode). Of course, using any one of the first to third semiconductor detectors 2, 3, and 7, the SPE of one section
A CT image may be obtained. (3) The first semiconductor detector 2 and the second semiconductor detector 3 are provided so as to face each other across the target portion, or the first semiconductor detector 2 (or the second semiconductor detector 3) The third semiconductor detector 7 and the third semiconductor detector 7 are provided so as to face each other with the target portion interposed therebetween, and the periphery of the subject is rotated, during which data collection is repeated at a plurality of angles to obtain a SPECT image ( SPECT data acquisition mode facing two detectors). (4) The first semiconductor detector 2 and the second semiconductor detector 3 are provided so as to be shifted by 90 ° along the entire rotation direction, and the periphery of the target portion is rotated in this state. Data acquisition is repeated at an angle, and a SPECT image can be obtained (two-detector 90 ° SPECT data acquisition mode). Needless to say, at this time, the third semiconductor detector 7 can be used to obtain a static image or a SPECT image of another site. (5) As shown in FIG. 6, three semiconductor detectors 2, 3,
7 is shifted by 120 ° along the entire rotation direction, and the same part is provided in a state where the same part is opposed from three directions. In this state, data is collected at a plurality of angles while rotating around the part by one third. One SPECT image can be repeatedly obtained (3-detector SPECT data acquisition mode).

As described above, according to the present embodiment, various data collection modes can be supported by freely combining the positional relationships of the three semiconductor detectors. The present invention is not limited to the embodiments described above, and can be implemented with various modifications. For example, by making the second semiconductor detector 3 detachable with respect to the slide mechanism 5, the second semiconductor detector 3 is purchased at the time of the first purchase, and then only the second semiconductor detector 3 is purchased. The addition has the advantage that it can be easily upgraded to a three-detector system.

[0021]

According to the present invention, by appropriately combining and arranging the first to third semiconductor detectors, a static data collection mode, a SPECT data collection mode, a two-detector opposed SPECT data collection mode, a two-detection mode are provided. 90 ° SPECT data acquisition mode, 3 detector SPE
Various data collection modes such as a CT data collection mode can be flexibly supported.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a nuclear medicine diagnostic apparatus according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a schematic structure of the semiconductor detector of FIG. 1;

FIG. 3 is a diagram showing a structure of first and second data acquisition systems in FIG. 1 as viewed from the side of a subject.

FIG. 4 is a diagram showing a structure of first and second data acquisition systems in FIG. 1 as viewed from a subject head side.

FIG. 5 is a view showing a state of sliding of the second semiconductor detector of FIG. 1;

FIG. 6 is a diagram showing a positional relationship among first, second, and third semiconductor detectors at the time of a three-detector SPECT of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st stand, 2 ... 1st semiconductor detector, 3 ... 2nd semiconductor detector, 4 ... Overall rotation mechanism, 5 ... Slide mechanism, 6 ... Stand running mechanism, 7 ... 2nd semiconductor detector 8, a second stand, 9: an entire rotating mechanism, 10 stand running mechanism, 11: movable section controller, 12: console, 13: image generation processor, 14: bed, 15: display.

Claims (9)

[Claims] 1. A first stand movably provided, and a gamma ray emitted from a radioisotope that is mounted on the first stand so as to be rotatable around a subject and is administered to the subject. A first semiconductor detector for directly converting to an electrical signal; and a first semiconductor detector mounted on the first stand so as to be rotatable around the subject together with the first semiconductor detector. A second semiconductor detector for converting the gamma ray into an electric signal, the second stand being rotatably mounted on the second stand, and being rotatably mounted around the subject on the second stand. A nuclear medicine diagnostic apparatus, comprising: a third semiconductor detector for conversion. 2. The first semiconductor detector according to claim 1, wherein said first semiconductor detector and said second semiconductor detector have an angle difference between said first semiconductor detector and said second semiconductor detector.
2. The nuclear medicine diagnostic apparatus according to claim 1, further comprising: means for sliding at least one of said semiconductor detector and said second semiconductor detector along a rotation direction. 3. The nuclear medicine diagnostic apparatus according to claim 1, wherein the second semiconductor detector is displaced from the first semiconductor detector by about 90 ° in a rotational direction. 4. The nuclear medicine diagnostic apparatus according to claim 1, wherein the second semiconductor detector is displaced from the first semiconductor detector by about 120 ° along the rotation direction. 5. The nuclear medicine diagnostic apparatus according to claim 1, wherein the second semiconductor detector is displaced from the first semiconductor detector by about 180 ° along the rotation direction. 6. A first stand movably provided, and a gamma ray emitted from a radioisotope that is provided on the first stand so as to be rotatable around a subject and is administered to the subject. A first semiconductor detector that directly converts to an electric signal, and a first semiconductor detector that can be mounted on the first stand so as to be rotatable around the subject together with the first semiconductor detector,
A second semiconductor detector that directly converts the gamma ray into an electric signal, a second stand movably provided, and the second stand is provided rotatably around the subject, A nuclear medicine diagnostic apparatus, comprising: a third semiconductor detector that directly converts a gamma ray into an electric signal. 7. A first stand movably provided, and a gamma ray mounted on the first stand and emitted from a radioisotope administered to the subject is directly converted into an electric signal. A first semiconductor detector, a second semiconductor detector detachably mounted on the first stand, and directly converting the gamma ray into an electric signal, and a second stand provided movably. And a third semiconductor detector mounted on the second stand and directly converting the gamma ray into an electric signal. 8. A first stand movably provided, and a gamma ray mounted on the first stand and emitted from a radioisotope administered to the subject is directly converted into an electric signal. At least two semiconductor detectors, a second stand movably provided, and a semiconductor detector mounted on the second stand and directly converting the gamma rays into an electric signal. Nuclear medicine diagnostic device. 9. The system according to claim 1, further comprising two physically separated first and second data collection systems, wherein said first data collection system is provided with at least two semiconductor detectors, A nuclear medicine diagnostic apparatus, wherein one semiconductor detector is provided in a data collection system.