JPH0452423B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in one-pass collimators for scintillation cameras.

Traditionally, scintillation cameras have used a one-pass collimator consisting of a diverging collimator to obtain an image of the patient's whole body in one whole-body scan (for example, a linear scan from the feet to the head or vice versa). There is.
This diverging collimator functions as a lens that reduces the image of the whole body, so although an image of the whole body can be obtained, the resolution has to be sacrificed, which may be inconvenient in some cases. .

This invention solves the above-mentioned inconvenience, and uses a scintillation camera that can simultaneously obtain a reduced image with low resolution of the whole body using a diverging collimator, and an enlarged image with high resolution or an unreduced image in a limited area. The purpose is to provide a one-pass collimator.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of one embodiment of the one-pass collimator 1 seen from above (the side other than the radiation incidence side, the scintillation camera side). The shielding plate 1a and a number of radiation shielding plates 1b parallel to the X direction are combined in a lattice pattern, and the direction of radiation incidence is regulated by each lattice-shaped opening. In the portion 11, the radiation shielding plate 1a opens toward the radiation incidence side (lower side in FIG. 2) to form a diverging collimator, as shown in FIG. 2, and in the lower half portion 12 of FIG. As shown in FIG. 3, 1a closes inward on the radiation incident side (lower side in FIG. 3) to form a converging collimator. The radiation shielding plate 1b in the X direction is placed perpendicularly to the paper plane of FIG. 1 in both the diverging collimator section 11 and the converging collimator section 12. Note that the conventional one-pass collimator is entirely composed of only a diverging collimator, such as the upper half 11 in FIG. 1, and in this embodiment, the lower half 12 is replaced with a converging collimator.

When viewed from the Y direction, as shown in FIG. 4, the visual field 13 of the diverging collimator section 11 is wide, and the visual field 14 of the converging collimator section 12 is narrow. Therefore, although the field of view 13 of the diverging collimator section 11 can cover the entire patient's body 2, the obtained image appears to be reduced in size and has a low resolution.
On the other hand, although the viewing range 14 of the converging collimator unit 12 can cover only a part of the body 2, it can obtain an enlarged image of that part, so the resolution is high.

When this one-pass collimator 1 is used, as shown in FIGS. 5 and 6, this one-pass collimator 1 is attached to a scintillation camera 3 to move the patient's body 2 from the feet to the head (or vice versa). ) With just one straight line scan, you can create a whole body image of the area 13 covered by the diverging collimator unit 11 and an enlargement of the central part of the body 2 such as the spine, neck, and head in the area 14 covered by the converging collimator unit 12. image can be obtained at the same time. In other words, the height direction of body 2 is Y
A one-pass collimator 1 is attached to a scintillation camera 3 so that the scintillation camera 3 is oriented in the Y direction, and the scintillation camera 3 is linearly scanned in the Y direction, and the position of the scintillation camera 3 in the Y direction is detected by a position detector 4. And the position signals X, Y obtained from the scintillation camera 3
indicates the position of the radiation incident on the scintillation camera 3 and is based on the coordinate system based on the scintillation camera 3 itself, so if the position signal Y is positive, the diverging collimator section 1
If it is negative, it indicates the position of the radiation that passed through the converging collimator section 12. Therefore, the position signal Y
A polarity determination circuit 5 determines whether the is positive or negative, and if it is positive, an addition circuit 6 adds the scintillation camera's Y-direction position signal and sends it to a display device 8 such as a CRT as a Y-direction deflection signal, and if it is negative, it is added. After adding the scintillation camera's Y direction position signal in circuit 7
It is sent as a deflection signal in the Y direction to a display device 9 such as a CRT. The position signal X output from the scintillation camera 3 is sent to the display devices 8 and 9 as a deflection signal in the X direction, and the unblank signal Z is sent as a brightness signal. Therefore, when one straight line scan from the toes to the head is completed, radiation incident points are accumulated on the display devices 8 and 9, respectively.
The display device 8 has an area 1 that covers the entire body 2.
3 (see FIG. 6) is displayed, and the display device 9 displays a narrow area 1 in the center of the body 2.
4 (see FIG. 6) will be displayed.

In addition, in the above embodiment, half of the one-pass collimator in the scan direction (Y direction), which was supposed to consist of only a diverging collimator, is replaced with a converging collimator, but if it is only a part in the scan direction, it can be replaced with a half part. It is not limited to , but may be some other part. In other words, if a part of the scan direction is made up of a collimator other than the diverging collimator, that part will be collected by the diverging collimator as it moves in the scan direction. This is because there will be no missing parts. In addition, if you do not need to enlarge the image and only need to obtain an unreduced image, use the radiation shielding plate 1 in the X direction.
Similarly to b, the radiation shielding plate 1a in the Y direction may also be provided with a parallel collimator perpendicular to the paper surface of FIG. 1 instead of the converging collimator.

As described above with respect to the embodiments, according to the present invention, a part of the one-pass collimator configured with a diverging collimator in the scanning direction is replaced with a diverging collimator and replaced with another collimator. In one scan, it is possible to simultaneously obtain a reduced-resolution image of the patient's whole body with a lower resolution and a higher-resolution image limited to some areas, which is not only more convenient, but also provides a schematic image. The accuracy of a doctor's diagnosis can be improved by simultaneously observing a detailed image of the whole body and a detailed image of a specific region.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a one-pass collimator according to an embodiment of the present invention, and FIG. 2 is a schematic plan view of a one-pass collimator according to an embodiment of the invention.
-A schematic cross-sectional view taken along line A; Figure 3 is a schematic cross-sectional view taken along line B-B in Figure 1; Figure 4 is a schematic diagram for explaining the viewing range. ,
FIG. 5 is a block diagram showing an example of application of the one-pass collimator of the above embodiment, and FIG. 6 is a schematic diagram for explaining the area covered by the visual field range. 1... One pass collimator, 11... Diverging collimator section, 12... Converging collimator section, 13, 14... Viewing range, 1a, 1
b... Radiation shielding plate, 2... Patient, 3... Scintillation camera, 4... Position detector, 5... Polarity determination circuit, 6, 7... Addition circuit, 8, 9... Display device.

Claims (1)

[Claims] 1 In a one-pass collimator for scintillation cameras consisting of a diverging collimator,
A one-pass collimator for a scintillation camera, characterized in that a part of the diverging collimator in the scan direction is replaced with another collimator.