JPH0452702Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is installed in the detector of a scintillation camera to detect the degree of non-linearity of the image of the scintillation camera, and detects radiation incidence in a prescribed pattern. The present invention relates to a phantom for linearity calibration that forms an image, and particularly to a phantom for linearity calibration of a scintillation camera that can collect pattern images accurately in a short time.

2. Description of the Related Art In recent years, scintillation cameras that have a function of correcting the linearity of images have become popular. In order to correct the linearity of this image, it is necessary to collect images of a prescribed pattern in advance, detect nonlinearity at each position on the image, calculate the amount of correction, and record it.
In order to collect images of this prescribed pattern,
This is done by attaching a linearity calibration phantom to the scintillation camera detector.

As shown in FIG. 3, the conventional phantom 1 for linearity calibration of this type has, for example, slits 2, 2, .
It was made up of lead plates 3 on which... were arranged at equal intervals. Here, the width of the slit 2 is, for example, 1 to
The spacing between the slits 2 was, for example, about 10 mm. Alternatively, as shown in Fig. 4, for example, a lead plate 3' having circular holes 4, 4, . Ta. Here, the diameter of the circular hole 4 was, for example, about 1 to 3 mm, and the interval between the circular holes 4 was, for example, about 10 mm. In this case, since the resolution at the periphery of the scintillation camera's field of view is lower than that at the center, if the width of the slit 2 or the diameter of the circular hole 4 is increased, the pattern image cannot be captured correctly, resulting in There is a problem that the degree of linearity cannot be detected.
It was not possible to increase the width of the slit 2 or the diameter of the circular hole 4 very much.

Problems to be Solved by the Invention In such conventional linearity calibration phantoms 1 and 1', the width of the slits 2 of the lead plates 3 and 3' is adjusted to match the resolution of the peripheral part of the field of view of the scintillation camera. Since the diameter of the circular hole 4 was assumed to be constant over its entire surface, it was necessary to attach the linearity calibration phantoms 1 and 1' to the detector of a scintillation camera to collect and form a radiation incidence image of a prescribed pattern. , which required a long time (for example, about 30 to 60 minutes). Therefore, in order to always maintain the best condition by correcting the linearity of the image of the scintillation camera, a great deal of time and effort is required to correct the linearity of the image. Therefore, the present invention aims to solve such problems.

Means for Solving the Problems The means of the present invention for solving the above problems includes a lead plate on which slits or holes are arranged at predetermined intervals, and has a function of correcting the linearity of an image. In the phantom for linearity calibration of the scintillation camera, which is attached to the detector of the scintillation camera and forms a radiation incidence image of a prescribed pattern, the width of the slit or the diameter of the hole in the lead plate is adjusted to the periphery of the lead plate. This is achieved by making the central part larger in comparison.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a diagram showing an embodiment of a phantom 5 for calibrating the linearity of a scintillation camera according to the present invention. This linearity calibration phantom 5 is attached to a detector of a scintillation camera (not shown) which has a function of correcting the linearity of an image, and is used to form a gamma-ray incident image of a prescribed pattern. As shown in b, it consists of a support plate 6 and a lead plate 7. The support plate 6 holds the lead plate 7 and serves as an attachment member to the detector, and is formed into, for example, a disk shape to match the planar shape of the detector.

A lead plate 7 is provided on one side of the support plate 6, as shown with diagonal lines in FIG. This lead plate 7 is used to collect a gamma ray incident image of a prescribed pattern and to detect nonlinearity at each position on the image, and as shown in FIG. ... are arranged and formed in parallel at predetermined intervals, for example, at equal intervals. Here, in the present invention, the width of each of the slits 8 is formed such that the width 8b at the central portion of the lead plate 7 is larger than the width 8a at the peripheral portion of the lead plate 7. For example, a circle with a radius smaller than the radius of the lead plate 7 is imagined at a position a suitable distance inward from the outer periphery of the lead plate 7, and one of the slits 8, 8, . . . The width 8b of the portion inside the circle may be made 2 to 3 times larger than the width 8a of the portion outside the circle. As a result, the time required to collect the γ-ray incident image of the prescribed pattern at the center of the field of view of the scintillation camera can be shortened by the increase in the width 8b of the slit 8.
Since the resolution in the central portion is generally high, the detectability of the prescribed pattern does not deteriorate. On the other hand, the width 8a of the slit 8 at the periphery of the lead plate 7
is as small as the conventional one, but due to the edge effect, in which the pattern image is denser in the periphery of the scintillation camera's field of view than in the center, the acquisition time of the gamma-ray incident image of the specified pattern does not slow down, and Since the width 8a of the slit 8 is small, a decrease in resolution can be suppressed and the prescribed pattern can be captured accurately.

FIG. 2 is a diagram showing another embodiment of the present invention.
In this embodiment, instead of the slits 8, holes 9, 9, etc., such as circular holes, are formed in a lead plate 7' at predetermined intervals, for example, at equal intervals. In this case, the diameter of each of the holes 9 is such that the diameter of the hole 9b in the central portion of the lead plate 7' is larger than the diameter of the hole 9a in the peripheral portion of the lead plate 7'. The method for forming it may be the same as in the case of the first embodiment described above. As a result, the time required to collect the γ-ray incident image of the prescribed pattern at the center of the field of view of the scintillation camera can be shortened by the increase in the diameter of the hole 9b, and since the resolution at the center is generally high, The detectability of the prescribed pattern does not deteriorate. Note that the shape of the hole 9 is not limited to the circular hole shown in FIG. 2, but may be a rectangular hole such as a quadrangular or hexagonal hole.

In FIGS. 1 and 2, the width of the slit 8 or the diameter of the hole 9 has a sharp step from a certain point toward the center of the lead plates 7, 7'. However, the present invention is not limited to this, and may be formed so that it continuously changes in size from the periphery toward the center.

Effects of the Invention As explained above, the present invention allows the width of the slit 8 or the diameter of the hole 9 in the lead plates 7, 7' to be adjusted.
Since the central part of the slit 7' is larger than the peripheral part of the slit 8, the collection and formation of the radiation (gamma ray) incident image of the prescribed pattern in the central part of the field of view of the scintillation camera is made possible by the width of the slit 8 or the hole 9.
It can be done faster by increasing the diameter. Therefore,
Overall, it is possible to shorten the time required to collect the radiation incident image of the prescribed pattern. Furthermore, since the resolution in the center of the field of view is generally high, the detectability of the prescribed pattern does not deteriorate. Therefore, the degree of nonlinearity at each position on the pattern image can be accurately detected. from these things,
In order to correct the linearity of the scintillation camera image and always keep it in the best condition, the correction work can be done quickly and accurately.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing an embodiment of a phantom for linearity calibration of a scintillation camera according to the present invention, FIG. 1b is a side view thereof, and FIG. 2 is a plan view showing another embodiment of the present invention. FIGS. 3 and 4 are plan views showing conventional linearity calibration phantoms, respectively. 5, 5'...Phantom for linearity calibration, 6...
...Support plate, 7,7'...Lead plate, 8...Slit,
8a... Width of the slit at the periphery, 8b...
Width of the slit in the center, 9... Hole, 9a
... Hole in the peripheral part, 9b... Hole in the central part.

Claims (1)

[Scope of utility model registration request] A scintillation system that has a lead plate with slits or holes arranged at predetermined intervals and is attached to the detector of a scintillation camera, which has the function of correcting the linearity of the image, and forms a radiation incidence image of a prescribed pattern. A phantom for linearity calibration of a scintillation camera, characterized in that the width of the slit or the diameter of the hole in the lead plate is made larger in the center than in the periphery of the lead plate. fan tome.