JPH0682158B2 - Body motion compensation device for scintillation camera - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scintillation camera, and more particularly to a device for preventing image deterioration due to movement of a subject.

BACKGROUND ART A scintillation camera administers RI (radioisotope) to a patient, and when the RI accumulates in a specific organ,
Radiation emitted from RI is measured to take an image of RI concentration distribution in the body, but it usually takes about 5-10 minutes when measuring a static organ such as the liver. Collect radiation data.

However, even a stationary organ does not move at all, and it is unavoidable that it moves due to respiratory movements, which causes image deterioration.

Conventionally, in order to perform such body movement correction, a method of collecting data in synchronization with breathing has been adopted.

Problems to be Solved by the Invention However, according to the conventional respiratory synchronization method, there is a problem that an extra device such as a respiratory detection device is required and the operation is complicated, and it copes with a sudden movement. I can't do it either.

The present invention provides a body movement correction device for a scintillation camera capable of performing body movement correction including respiratory movements and other sudden movements by a simple operation without requiring a separate device. The purpose is to

Means for Solving Problems A body movement correction device for a scintillation camera according to the present invention includes a unit that collects and stores data regarding a radiation incident position for each unit time, and a unit time unit configured by the collected data. Means for calculating the position of the center of gravity of the image of
It comprises means for shifting the image for each unit time so that the barycentric position is always the same position.

Action The detector of the scintillation camera outputs data on the incident position each time the radiation is incident.By collecting this data every unit time, an image showing the RI concentration distribution can be obtained every unit time. become. Then, the centroid position of each image for each unit time is calculated, and each image is shifted so that the centroid position is always the same position.

As a result, the center of gravity of the organ image is always aligned even if the organ or the like moves cyclically or suddenly with the respiratory motion.
By combining two images, an excellent image that is not affected by motion can be obtained.

Embodiment In FIG. 1, a detector 2 of a scintillation camera is directed toward a subject 1, and from this detector 2, position signals X, Y representing the incident position of each γ-ray are incident.
Occurs. The position signals X and Y are interface circuits 3
The image acquisition memory 4 is sent via the, and the content of the address corresponding to the position is added by "1". In this way, when the detector 2 measures the γ-rays from the subject 1 for a certain period of time, data regarding the number of γ-rays incident at each position is collected, that is, an image is formed.

Here, for example, a static image of a 64 × 64 matrix of the liver is obtained. Then, first, the CPU 5 controls the timer 8 to control the interface circuit 3 and, for example, with 0.1 seconds as a unit time, an image is obtained depending on how many γ-ray incident numbers are counted in each of the above-mentioned matrices for each unit time. For each unit time. This is performed for about 10 minutes, and a large number of liver images every 0.1 seconds as shown in FIG. 2 are obtained in the image acquisition memory 4. afterwards,
Each of these images is read out, and the centroid counting circuit 6
Decide the centroid of the liver image every 0.1 seconds. As shown in Fig. 2, the position of the center of gravity of the liver image is Pa first, then
If it moves to Pb, Pc, ...
Pa, Pb, Pc, ... are required. Therefore, for example, with the first center of gravity position Pa as the reference position, the differences ΔX and ΔY from the center of gravity position Pb of the second image are calculated and sent to the shift circuit 7.
Then, the shift circuit 7 subtracts the above differences ΔX and ΔY from the position signals X and Y relating to the second image read from the image acquisition memory 4, and the result (X−Δ) is obtained.
X) and (Y-ΔY) signals are returned to the image acquisition memory 4.
In this way, the second image can be two-dimensionally shifted so that the barycentric position Pb of the second image matches the barycentric position Pa of the first image. By performing such an operation for each of the images every 0.1 seconds, the centroid positions of all the images can be matched.

Therefore, by superimposing these images in the image acquisition memory 4, it is possible to obtain a liver image in which sufficient γ-ray counts have been accumulated by measuring for about 10 minutes.
Even if the liver moves cyclically with breathing motion or suddenly moves, since the position of the center of gravity of each image for each unit time is aligned, the effect is eliminated and body movement is eliminated. A still image of the liver, which is prevented from being deteriorated by

In the above description, the body movement correction operation is performed after collecting a large number of images for each unit time in the image acquisition memory 4. However, when an image for one unit time is obtained in the image acquisition memory 4, immediately The center-of-gravity position is calculated, the differences ΔX and ΔY from the reference center-of-gravity position are obtained, and the two-dimensional shift is performed by this, and the image data after the shift is stored in the 1 × 64 × 64 matrix in the image acquisition memory 4. You may make it collect in one image collection area. By doing this,
The memory capacity of the image acquisition memory 4 can be reduced.

EFFECTS OF THE INVENTION According to the present invention, periodic body movements such as respiratory movements or sudden body movements can be performed without using a special device for detecting body movements or complicating the operation thereof. An excellent image can be obtained by preventing deterioration of the image due to movement.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing an example of an image obtained every unit time. DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Detector 3 ... Interface circuit, 4 ... Image acquisition memory 5 ... CPU, 6 ... Centroid calculation circuit 7 ... Shift circuit, 8 ... Timer

Claims (1)

[Claims] 1. A means for collecting and storing data on a radiation incident position for each unit time, a means for calculating a barycentric position of an image for each unit time constituted by the collected data, and a barycentric position A body motion correction device for a scintillation camera, which comprises means for shifting the image for each unit time so that it is always at the same position.