JPH06230136A - Scintillation camera - Google Patents

Abstract

PURPOSE:To deal with a specimen having an arbitrary figure while facilitating the collection of data by keeping the distance between the surface of the specimen and a detector constant at all times at the time of collection of data for reconstructing the tomographic image of the specimen. CONSTITUTION:A sensor control circuit 20 actuates each pair of sensors sequentially at high speed from No.1 to No.N and ON/OFF states thereof are then detected and fed to a stage control circuit 30. In other words, ON/OFF states of the pairs of sensors are detected at high speed from No.1 to No.N so that the sensors function like a single sensor thus forming a noncontact surface sensor 10. A detector separates from or approaches a specimen depending on the ON/OFF function of the sensor 10 thus keeping a constant distance between them. On the other hand, positional data is recorded at each predetermined position of the detector and delivered to an image processing section 40 in order to extract the outline of the specimen.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to scintillation cameras, and more particularly to scanning an object with a scintillation camera detector.

[0002]

2. Description of the Related Art A scintillation camera is used to obtain a tomographic image of a subject by detecting γ-rays emitted from radioisotopes injected into the subject while the detector scans the subject. To be done.

The conventional scintillation camera takes the following means to scan the periphery of the subject.

The first method is a so-called four-point setting method. In this method, four points are input before scanning with the width direction of the subject as the long axis and the thickness direction as the short axis, and the detector is moved so that an elliptical orbit passing through them is drawn. To scan. That is, in this method, the distance from the center of rotation in the radial direction of rotation is input every 90 ° rotation, the ellipse for each quadrant is calculated, and the detector moves on the elliptical orbit.

The second method is to rotate the detector around the subject one time before data acquisition so that the trajectory is memorized and the detector is moved along the trajectory. To scan.

However, according to the scanning method of the subject as described above, the first method requires setting the trajectory of the detector by setting four points, and the second method requires the trajectory of the detector to move. Work to remember is required. Furthermore, in the conventional scanning method of the subject, since it is necessary to set the trajectory of the detector before the start of data collection, after the start of data collection, or after the trajectory of the detector is set, When the patient moves, it is difficult to correct the trajectory.

In particular, in the case of the four-point setting method which is the first method, the moving trajectory of the detector is set so as to draw an elliptical trajectory ignoring the contour of the subject, so that the ideal recent movement for the subject is achieved. No contact trajectory can be obtained.

[0008]

As described above, in the conventional scintillation camera, the movement trajectory of the detector is set,
Alternatively, when the teaching work of the trajectory is required and the subject moves after the start of data collection or after the movement trajectory of the detector is set, the trajectory cannot be corrected. In particular, the conventional 4
In the case of the point setting method, there is a problem that it is not possible to cope with an arbitrary body shape of the subject.

The present invention has been made based on the above circumstances, and it is easy to collect data for reconstructing a tomographic image of a subject without requiring setting of a moving trajectory of a detector. Therefore, an object of the present invention is to provide a scintillation camera that can handle any body type of the subject.

[0010]

The present invention has taken the following means in order to solve the above problems.

In a scintillation camera configured to obtain a tomographic image of a subject by administering a radioisotope to the subject and detecting γ-rays emitted from the radioisotope with a detector. A distance holding means is provided for always holding the distance between the surface of the subject and the detector constant when collecting data for reconstructing a tomographic image.

[0012]

As a result of taking the above-mentioned means, the following effects occur.

According to the scintillation camera of the present invention, when collecting data for reconstructing a tomographic image of the subject, the detector is provided by the distance holding means for always keeping the distance between the surface of the subject and the detector constant. Moves while holding the surface of the subject always constant, it is not necessary to set the 4-point position in advance to set the movement trajectory of the detector as in the 4-point setting method. There is no need to memorize the scintillation camera. Therefore, the time required for setting the movement trajectory of the detector from the positioning of the subject is not required, and the data acquisition time is shortened.

Further, since the detector is moved by the distance holding means so that the position of the subject is always constant, it is necessary to stop the data collection even when the subject moves during the data collection. Furthermore, the present invention can be applied to a subject of any body type, and an optimum detector movement trajectory can be obtained for a subject of any body type.

In addition to the above, by reading the movement trajectory of the detector, an accurate contour of the subject can be obtained as data, and therefore as data for performing more accurate absorption correction when reconstructing a tomographic image. Can be used.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 are respectively a schematic block diagram and a schematic configuration diagram of a scintillation camera according to the first embodiment of the present invention.

1 and 2, the scintillation camera of the present invention has a plurality of light emitting sensors 11 _{1 to} 11 _N and a plurality of light receiving sensors 12 ₁ provided corresponding to the light emitting sensors 11 _{1 to} 11 _N. ~ 12 _N non-contact surface sensor 10 (hereinafter referred to as "non-contact surface sensor")
ON / OFF of the non-contact surface sensor 10 is detected, and each of the light emitting sensors 11 _{1 to} 11 _N and the light receiving sensor 1 is detected.
A sensor control circuit 20 for controlling switching from 2 _{1 to} 12 _N
And a gantry control circuit 30 that controls the drive of a gantry unit (not shown) of the scintillation camera, and a detector rotation drive unit 32 that rotatably drives the detector 50 mounted on the gantry unit.
And a subject 51a including the detector 50 and the bed 51b
(Hereinafter, referred to as “subject 51 or the like”) A detector detachment / proximity operation drive unit 34 for performing a detachment action and a proximity action of the detector 50 with respect to the subject 51 or the like in order to keep the distance constant. And an image processing unit 40 that processes image data obtained by the scintillation camera. 1 and 2, 13 _{1 to} 13 _N are light emitting sensors 11 _{1 to} 11 _N and light receiving sensors 12 _{1 to} 12 _{N, respectively.}
Shows an optical axis connecting with the optical axis. The optical axes 13 _{1 to} 13 _N are parallel to the detection surface of the detector 50 and are arranged between the detector 50 and the object 51a to form a surface sensor. . In addition, the light emitting sensors 11 _{1 to} 11 _N and the light receiving sensors 12 ₁ to ₁ 1
2 _N are arranged so as to form a pair, and the optical axes 13 ₁ to 1
It suffices that 3 _N form a surface sensor as a whole, and they may be randomly arranged.

With the above-mentioned structure, in the following description, the state in which the light emitted from the light emitting sensors 11 _{1 to} 11 _N is received by all the light receiving sensors 12 _{1 to} 12 _N provided facing each other is OFF. Then, a state in which there is an object (for example, a subject or the like) that blocks light between the facing sensors (that is, on the optical axis 13) and cannot be detected by any of the light receiving sensors 12 _{1 to} 12 _N is set to ON.

The sensor control circuit 20 sequentially operates each of the above sensor pairs at high speed from the 1st to the Nth, and turns them on.
ON / OF of each sensor pair by detecting the state of ON / OFF operation
The F operation state is output to the gantry control circuit 30. Thus, the ON / OF of the first to Nth sensor pairs
The non-contact surface sensor 10 is formed by detecting the F operation state at high speed and operating like one sensor.

The gantry control circuit 30 is the sensor control circuit 20.
The movement of the detector 50 is controlled according to the data collection conditions and the like based on the information from In FIG. 2, the arrow A indicates the detector 5.
0 indicates an operation direction in which the periphery of the subject 51 or the like rotates about the subject, and the detector rotation drive unit 32 causes the detector 5 to rotate.
0 is driven. Further, an arrow B indicates an operation direction in which the detector 50 is separated from the subject 51 or the like, and an arrow C indicates a detector 50.
Indicates the direction of movement in the vicinity of the subject 51 or the like. these,
The detectors 50 are both driven by the detector separation / proximity operation driving unit 34 with respect to the directions of the proximity operation and the separation operation. Based on the control signal from the gantry control unit 30, these arrows A,
The detector is driven by the detector rotation drive unit 32 in the directions of arrows B and C.
Further, by driving the detector separation / proximity operation drive unit 34, an accurate movement trajectory of the detector 50 can be obtained.
Hereinafter, driving the detector in the direction of arrow A is referred to as "rotational driving", driving the detector in the direction of arrow B is referred to as "separation operation", and driving the detector in the direction of arrow C is referred to as "proximity operation". Called.

As described above, the scintillation camera of the present invention is provided with the non-contact surface sensor 10, and the ON / OFF operation of the non-contact surface sensor causes the detector 50 to perform the separating operation or the proximity operation, and the detector 50. The distance between the subject 51 and the subject 51 is controlled to be constant.

Further, by recording position data for each predetermined position of the detector 50, for example, for each 90 ° rotation angle, and outputting this data to the image processing section 40, the contour portion of the subject 51 or the like is recorded. 5 can be extracted.
One contour portion can be accurately extracted, and this contour portion can be used as absorption correction data.

The operation and effect of the present invention in the case where the scintillation camera moves to a predetermined position when collecting the data of the subject in the above-mentioned structure is shown in FIG.
This will be specifically described with reference to (a) and FIG. 3 (b). 3A and 3B, the same parts as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. 3A is a front view showing a schematic configuration of a detector unit of the scintillation camera of the present invention, like FIG. 2, and FIG.
It is a side view of (a).

As shown in FIG. 3, according to the present invention, when the detection moves in the directions of arrows A to D, as described above, the ON / OFF state of the non-contact surface sensor 10 is always kept in the sensor control circuit. Monitored by 20, the subject 51 and the detector 5
It is controlled so that the distance from 0 is kept constant. Here, the arrow D indicates the direction in which the detector 50 is driven from the head of the subject 51 or the like to the legs or vice versa.

As described above, according to the present invention, the non-contact surface sensor 10 is arranged in the detecting portion of the detector 50 so that the distance between the detector 50 and the object 51 or the like is always kept constant.
When the subject 51a is placed on a bed and the detector 50 is moved to a predetermined position, the following operation becomes possible. Here, when the detector 50 moves, the detector 50 and the subject 51a may come into contact with each other when the detector 50 is rotationally driven (when the detector 50 is moved in the direction of arrow A). It is limited to parallel movement (movement in the direction of arrow D) and proximity movement of the detector 50 (movement in the direction of arrow C). In this case, according to the present invention, the detector 50 and the subject 51
Since the distance between and is always constant, as shown below, the detector 50 can be quickly moved to a desired position without being aware of the contact between the detector 50 and the subject 51 or the like. That is, quick alignment can be performed.

(1) During rotation drive of the detector 50 (arrow A
(When moving in the direction), the non-contact surface sensor 10 detects the subject 51
When a or the bed 51b is detected, the detector 50 automatically moves away from the detector 50a, so that the operator 51a or the bed 51
Positioning can be performed promptly without being aware of the contact between b and the detector 50.

(2) When the non-contact surface sensor 10 detects the object 51a or the bed 51b while the detector 50 is moving in parallel to the object 51 or the like (when moving in the direction of arrow D), Since the detector 50 automatically moves apart, the operator can quickly perform the alignment without being aware of the contact between the subject 51a or the bed 51b and the detector 50.

(3) Since the detector 50 is brought close to the subject 51a or the bed 51b, the non-contact surface sensor 10 is operated while the operator is moving close to the object 51 (when moving in the direction of arrow C).
When the object 51a or the bed 51b is detected by the detector 50, the detector 50 automatically stops the proximity operation, so that the operator promptly does not consider the distance and contact between the object 51a or the bed 51b and the detector 50. Alignment can be done.

As mentioned above, according to the present invention, the detector 50
Since the ON / OFF of the non-contact surface sensor 10 is detected during the rotational driving, parallel movement, etc. of the detector 50, the proximity movement or the separation movement of the detector 50 is stopped. Positioning can be performed promptly without being aware of the distance and contact between the bed 51b and the detector 50.

The above description has been made on the case where the detector 50 is moved to a desired position in order to collect the data of the subject 51a. Below, a method for extracting the body axis of the subject 51a will be described. This will be described with reference to FIGS. Figure 4
Shows a schematic diagram for obtaining a body axis, and FIG. 5 shows an actual flow chart thereof. In FIG. 4, point O indicates the center of rotation of the detector, and point O ′ indicates the body axis calculated by the present invention.

As shown in FIG. 4, the detector is rotated at 90 ° position and 180 ° at clockwise position when viewed from the head, with the lower part of the object being at 0 ° position.
The position is 270 °.

In FIG. 5, first, the detector 50 moves to the 0 ° position by the operation as shown in FIG. 3 (step A1). Next, until the non-contact surface sensor 10 is turned on,
The detector 50 performs the proximity operation (step A2). Then, when the non-contact surface sensor 10 is turned on, the proximity operation is stopped, and the position data (x coordinate value and y coordinate value in FIG. 4) of the detector 50 at that position is stored (step A3). The rotational position of the detector 50 is rotated by 90 ° from the current position (step A4). It is determined whether the data collection for 360 ° is completed, that is, whether the detector 50 has returned to the 0 ° position (step A
5). In step A5, if data collection of the detector 50 position at each position from 0 ° to 270 ° is not completed, the process is repeated from step A2. If the data acquisition at the detector 50 position has been completed, dx = (d _{270 °} -d _{90 °} ) / 2 dy = (d _{180 °} -d _{0 °} ) / 2 is calculated (step A6). Where d _{0 °} ,
d _{90 °,} d _{180 °,} d _{270 °,} respectively, detector position 50 is 0 °, 90 °, 180 ° , indicating the position on the XY coordinates of the center point and O in 270 °.

As described above, the distance holding means such as the sensor control circuit 20 of the present invention can be used to accurately and automatically extract the positions dx and dy of the body axis O '.

Since accurate body axis data can be obtained as described above, the body axis O'and the rotation center O of the detector 50 coincide with each other when used in combination with a device capable of adjusting the position of the subject 51a. Thus, the subject position can be moved, and the subject can be automatically positioned. Further, since the body axis O ′ and the rotation center O of the detector 50 coincide with each other, the image quality during reconstruction is improved. Further, it is possible to efficiently collect data by eliminating waste of separation / proximity operation of the detector.

The present invention is a single photon emission tomography apparatus (hereinafter referred to as "SPECT apparatus").
A second embodiment applied to will be described below. The configuration of the device is the same as that of the first embodiment, and therefore its explanation is omitted. Also, this second
The embodiment shows an example in which the present invention is applied to two types of data collection, that is, step collection and continuous collection of SPECT data. Here, step collection of SPECT data means S
In a PECT apparatus, when collecting data, the detector collects SPECT data while rotating and driving, but the detector temporarily stops rotating at every predetermined angle, for example, every 60 °, and the detector Collect SPECT data at the stopped position. Then, when the data collection at that position is completed, the detector is rotationally driven to move to the next data collection position, and SPECT data is similarly collected. On the other hand, the continuous acquisition of SPECT data is a method of collecting SPECT data without stopping the rotational driving of the detector.

First, the step collection of SPECT data will be described with reference to FIGS. 6 to 10. FIG. 6 and FIG. 7 are diagrams respectively showing an outline and a flowchart of the operation of the prior art at the time of step collection of SPECT data. 8 to 10 are diagrams respectively showing an outline and a flowchart of the operation of the device of the present invention at the time of step collection of SPECT data.

A conventional technique will be described with reference to FIGS. 6 and 7.

Conventionally, as shown in FIG. 6, the above-mentioned four-point input (A ₁ ~
A ₄ ) is performed, an elliptical orbit L is calculated based on the input points A _{1 to} A ₄ , and the orbit is traced step by step to move the detector 50. A specific SPECT data collection method will be described with reference to the flowchart of FIG.

First, as the initial setting position of the detector, 90
Set and input the four point positions A _{1 to} A ₄ for each ° (step B
1). Next, the trajectory is calculated so that the detector passes through the four input points, and the movement trajectory L of the detector is set (step B2). Then, the SPECT data is collected for a predetermined time (step B3). When the collection of SPECT data is completed, the detector rotation drive is started to the next SPECT data collection position, and at the same time, the detector separating operation or the proximity operation is started (step B4). Whether or not the detector comes into contact with the subject or the like while the detector is rotating is detected by, for example, a contact sensor attached to the detector to determine (step B5). Here, as shown in FIG. 6, when the detector surface 50a moves from A ₃ to A ₄ , the subject 51
When it comes into contact with a, the detector 50 stops its operation and performs a separating operation (step B6). Specifically, as shown in FIG. 6, the detector 50 temporarily stops the rotation drive at the point F ₁ and performs the separating operation up to the point F ₂ . Then, the detector 50 which starts the rotational driving from the point F ₂ and passes through A ₄
Recalculate the moving trajectory M of the new ellipse of (step B
7), the rotational drive of the detector 50 restarts from the F ₂ point (step B8).

Then, in step B5, the subject 5
If the detector 50 does not come into contact with 1a, S
It is determined whether or not the detector 50 has reached the PECT data collection end position (step B9), and the detector 50 moves to the SPEC.
If the T data acquisition end position has not been reached, the process is repeated from step B3. If not, the SPECT data acquisition is ended.

Contrary to the above operation, the present invention is based on FIGS.
Further, as shown in FIG. 10, the operation after the start of collection (the operation shown in step B1 and step B2) is unnecessary.
8 to 10 are diagrams respectively showing an outline and a flowchart of the operation of the device of the present invention at the time of step collection of SPECT data. FIG. 10 shows step C7 in FIG.
3 is a flowchart showing the details of FIG.

The operation of the present invention will be described with reference to FIGS.

The rotation drive of the detector is started without setting the four points as shown in FIG.

The sensor control circuit 20 determines whether the non-contact surface sensor 10 is ON or OFF (step C1). In this case, if the non-contact surface sensor 10 is OFF, the proximity operation of the detector 50 is started (step C).
2). This operation is continued until the non-contact surface sensor 10 is turned on (step C3). Then, when the non-contact surface sensor 10 is turned on, the proximity operation of the detector 50 is stopped (step C4), and the process proceeds to the next step C5. In step C1, the non-contact surface sensor 10 is turned on.
Also in case of, it progresses to step C5.

At step C5, the position data of the detector 50 is stored in a recording device (not shown) (step C).
5). In this case, the contour data of the subject can be obtained by storing the position data of the detector 50 in the recording device for each predetermined collection angle of the SPECT data, and the contour can be used as the data for absorption correction of the subject. The operation for obtaining the contour of the subject can be automatically performed.

Then, SPECT data is collected for a predetermined time (step C6). The automatic movement operation by the non-contact surface sensor described later in detail is performed (step C7). Then, it is determined whether or not the detector 50 has reached the SPECT data acquisition end position, and if the detector 50 has reached the SPECT data acquisition end position, the SPECT data acquisition operation is terminated. The operation is repeated from C5 (step C8).

The automatic movement operation of the detector at the time of step collection of SPECT data by the non-contact surface sensor 10 in step C7 of FIG. 9 will be described in detail with reference to FIG.

The detector 50 is driven to rotate, and the next SPECT
The rotation driving operation of the detector 50 starts toward the data collection position (step D1). During the rotational driving of this detector, the non-contact surface sensor 10 detects either ON or OFF (step D2). In step D2, if the detector is ON, proceed to step D6,
If the detector is off, go to step D3. In this case, unlike the conventional technique shown in FIG.
Rotation drive does not stop.

In step D2, the non-contact surface sensor 1
When 0 is OFF, the sensor control circuit 20 detects that the detector and the subject are distant from each other, so that the detector proximity operation starts (step D3) and the non-contact surface sensor 10 is turned ON. Until the detector is sufficiently close to the subject (step D).
4). Then, the detector proximity operation is stopped when the non-contact surface sensor is turned on (step D5). Also,
In step D2, when the non-contact surface sensor 10 is ON, the detector and the subject are too close to each other and may come into contact with each other. Therefore, the detector separating operation is started (step D6). The detector separating operation is repeated until 10 is turned off, that is, until the distance between the detector and the subject becomes a predetermined distance or more (step D).
7). When the non-contact surface sensor 10 is turned off,
The detector separating operation is stopped (step D8).

Next, it is determined whether or not the detector 50 has reached the next SPECT data collection position, and if the detector 50 has not reached the next SPECT data collection position, the operation from step D2 is repeated. Detector 50 is the next SPEC
If the T data collection position has been reached, the detector 50 stops the rotation drive and proceeds to the next step D10. Then, in step D10, the non-contact surface sensor 10 is ON or O
Whether it is FF or not is detected (step D10).
If the non-contact surface sensor 10 is ON in step D10, the distance between the detector and the subject is sufficiently short, and thus the automatic movement operation ends. If the non-contact surface sensor 10 is OFF in step D10, the distance between the detector 50 and the object 51 or the like is not sufficiently short, and therefore the proximity operation of the detector 50 is started (step D11). 1
Until 0 turns ON, that is, the detector 50 and the subject 5
The operation is repeated until the distance to 1 becomes sufficiently short (step D12). When the non-contact surface sensor 10 is turned on, the proximity operation of the detector is stopped (step D13).

By performing the above operation until the detector 50 reaches the collection end position of the SPECT data, the SPECT data of the subject 51 and the like 51 and the subject 51, etc., which are continuous.
The contour data of can be obtained. The state of the movement path of the rotational drive of this detector is shown by the curve L in FIG.

Also, by effectively providing a delay time between each of the separating operation and the approaching operation (for example, after the above step D5, step D8, or step D13), an inching operation is performed. It is possible to eliminate unnecessary detailed operations. Further, by setting the rotational speed of the detector and the moving speed of the proximity movement / separation movement of the detector to appropriate values, a more accurate trajectory, that is, an accurate contour of the subject or the like can be secured. Further, it is possible to avoid contact with the subject and the bed.

In addition, the area data is newly detected and stored by the non-contact surface sensor during the detaching operation of the detector, and if the area data is increasing, the detaching operation is speeded up to detect the object and the bed. Avoid contact. Moreover, even if the subject moves during the movement of the detector, the movement of the detector is not stopped or interrupted, and the detector can always move to the optimum position following the movement of the subject.

FIG. 11 is a flow chart showing an application example of the present invention at the time of continuous acquisition of SPECT data.

The detector 50 is rotationally driven, and at the same time when the collection of SPECT data is started, the rotational driving operation of the detector 50 is started (step E1). While the detector is rotating, the non-contact surface sensor 10 detects whether it is ON or OFF (step E2). In step E2, if the detector is ON, the process proceeds to step E6, and if the detector is OFF, the process proceeds to step E3. In this case, unlike the conventional technique shown in FIG. 7, the rotational drive of the detector 50 does not stop.

In step E2, the non-contact surface sensor 1
When 0 is OFF, the sensor control circuit 20 detects that the detector and the subject are distant from each other, so that the detector proximity operation starts (step E3) and the non-contact surface sensor 10 is turned ON. Until the detector is sufficiently close to the subject (step E).
4). Then, when the non-contact surface sensor is turned on, the detector proximity operation is stopped (step E5). Also,
In step E2, when the non-contact surface sensor 10 is ON, the detector and the subject are too close to each other and may come into contact with each other. Therefore, the detector separating operation is started (step E6), and the non-contact surface sensor The detector separating operation is repeated until 10 is turned off, that is, until the distance between the detector and the subject becomes a predetermined distance or more (step E).
7). When the non-contact surface sensor 10 is turned off,
The detector separating operation is stopped (step E8).

Then, it is judged whether or not the detector 50 has reached the collection end position of the SPECT data (step E).
9) If the detector 50 has not reached the collection end position of the SPECT data, the operation from step E2 is repeated.
If the detector 50 has reached the SPECT data collection end position, the detector 50 ends the rotation drive operation (step E10).

When the SPECT data is continuously collected as described above, the contour of the subject is obtained by storing the data of the detector position at every predetermined angle while the detector is rotationally driven. Can be used as absorption correction data. The operation of obtaining the contour of the subject can be automatically performed.

In addition, during each of the above separating operation and approaching operation (for example, the above step E5 or step E8).
By effectively providing the delay time after the above, unnecessary fine operation such as inching operation can be eliminated. Further, by setting the rotational speed of the detector and the moving speed of the proximity movement / separation movement of the detector to appropriate values, a more accurate trajectory, that is, an accurate contour of the subject or the like can be secured. Further, it is possible to avoid contact with the subject and the bed.

In addition, the area data is newly detected and stored by the non-contact surface sensor during the separating operation of the detector, and if the area data is increasing, the separating operation is speeded up to detect the object and the bed. Avoid contact. Moreover, even if the subject moves during the movement of the detector, the movement of the detector is not stopped or interrupted, and the detector can always move to the optimum position following the movement of the subject.

In the above embodiment, the sensor for detecting the distance between the detector and the subject is a non-contact type surface sensor in which a plurality of light emitting sensors and light receiving sensors are combined to function as one surface sensor. The contact type surface sensor is not limited to the non-contact type. That is, any sensor may be used as long as it functions as a surface sensor. Also, regarding the type of the surface sensor, a plurality of optical sensors are used in the above-mentioned embodiment, but not limited to optical sensors, any sensor such as a sensor using sound waves may be used.

The present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0064]

According to the present invention, the following effects can be obtained.

According to the scintillation camera of the present invention, when the data for reconstructing the tomographic image of the subject is collected, the detector is provided by the distance holding means for keeping the distance between the surface of the subject and the detector constant. Moves while holding the surface of the subject always constant, it is not necessary to set the 4-point position in advance to set the movement trajectory of the detector as in the 4-point setting method. There is no need to memorize the scintillation camera. Therefore, the time required for setting the movement trajectory of the detector from the positioning of the subject is not required, and the data acquisition time is shortened.

Further, since the detector is moved by the distance holding means so that the position of the subject is always constant, it is necessary to stop the data collection even when the subject moves during the data collection. Furthermore, the present invention can be applied to a subject of any body type, and an optimum detector movement trajectory can be obtained for a subject of any body type.

In addition to the above, by reading the movement trajectory of the detector, an accurate contour of the subject can be obtained as data, and therefore as data for performing more accurate absorption correction when reconstructing a tomographic image. Can be used.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a scintillation camera according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a scintillation camera according to an embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a detector unit of a scintillation camera.

FIG. 4 is a schematic diagram for obtaining a body axis.

FIG. 5 is a flowchart for obtaining a body axis.

FIG. 6 is a diagram showing an outline of an operation at the time of step collection of conventional SPECT data.

FIG. 7 is a flowchart showing an operation during step collection of conventional SPECT data.

FIG. 8 is a diagram showing an outline of an operation during step acquisition of SPECT data of the present invention.

FIG. 9 is a flowchart showing an operation at the time of step collection of SPECT data of the present invention.

10 is a flowchart showing the detailed operation of step C7 in FIG.

FIG. 11 is a flowchart showing an application example of the present invention at the time of continuous collection of SPECT data.

[Explanation of symbols]

10 ... Non-contact surface sensor, 11 ... Luminescence sensor (11 ₁ to 1)
1 _N ), 12 ... Light receiving sensors (12 _{1 to} 12 _N ), 13 ...
Optical axis (13 _{1 to} 13 _N ), 20 ... Sensor control circuit, 30
... gantry control circuit, 32 ... detector rotation drive unit, 34 ... detector separation / proximity operation drive unit, 40 ... image processing unit, 50 ... detector, 51 ... subject, etc. (51a ... subject, 51b ... bed) .

Claims (3)

[Claims] 1. A scintillation camera configured to obtain a tomographic image of a subject by administering a radioisotope to the subject and detecting γ-rays emitted from the radioisotope with a detector. A scintillation camera comprising distance holding means for always holding the distance between the surface of the subject and the detector constant when collecting data for reconstructing a tomographic image of the subject. 2. The distance holding means controls a non-contact type surface sensor arranged between a detection surface of the detector and the subject, and controls the operation of the surface sensor, and turns on the surface sensor.
A sensor control circuit for detecting ON / OFF, and a separation / proximity operation driving unit for controlling separation / proximity operation of the detector from / to the object based on a detection result of the sensor control circuit. The scintillation camera according to claim 1, wherein: 3. When collecting data for reconstructing a tomographic image of a subject, the position of the detector is recorded every time the detector rotates by a certain angle, and the recorded position of the detector is recorded. The scintillation camera according to claim 1, further comprising means for determining at least one of an accurate contour and a body axis of the subject based on the scintillation camera.