JP3315269B2 - Radioactive sample measurement plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate for measuring a radioactive sample, and more particularly to a scintillator-type microplate having a plurality of wells.

[0002]

2. Description of the Related Art Conventional radioactive sample measurement plates include:
A plurality of wells having an upper opening are formed. After the liquid radioactive sample mixed with the liquid scintillator is injected into the well, the plate is set on a radioactive sample analyzer or the like. Next, the light receiving surface of the photomultiplier is brought close to the bottom of the well or the like, and light from the liquid scintillator is detected by the photomultiplier. Incidentally, the well in the conventional plate for measuring a radioactive sample had a diameter of, for example, 8 mm and a depth of 10 mm.

[0003] The radioactive sample measurement plate is a kind of microplate. In addition, although it is for measuring absorbance, applications relating to microplates include, for example, JP-A-57-70459 and JP-A-60-22.
No. 2753 and Japanese Utility Model Laid-Open No. 2-7553.

[0004]

However, in the conventional measurement of a radioactive sample, a liquid scintillator must be mixed with the sample, which is complicated and increases the cost. In addition, there is a problem of quenching as a problem peculiar to the liquid scintillator, and in some cases, mixing of the liquid scintillator makes the sample turbid, which adversely affects measurement accuracy. Further, when an organic liquid scintillator or the like is used, a special treatment is required for disposal, which has increased the complexity.

Conventionally, even if the sample in the well is shaken by external vibration, it is necessary to make the well deep to some extent so that the sample does not jump out, and it is difficult to make the plate thinner. At the same time, it has been difficult to reduce the amount of sample injected into each well.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to measure a radioactive sample without using a liquid scintillator in order to solve the problems associated with the liquid scintillator. And

Another object of the present invention is to reduce the volume of a well in order to effectively use a valuable sample.

Another object of the present invention is to reduce the thickness of the measurement plate.

Another object of the present invention is to prevent the sample in the well from scattering or the like due to external vibration.

[0010]

In order to achieve the above-mentioned object, the present invention provides a plate having at least one well for sucking a liquid radioactive sample, wherein the well comprises a bottom plate and a lid plate. It is formed as a small gap between the radiation
Having a suction space into which a neutral sample is sucked, a sample receiving port communicating with the suction space, and an air hole communicating with the suction space, and at least one of a bottom plate and a cover plate of the well is formed of a solid scintillator. It is characterized by having been done. Further, the present invention is characterized in that both the bottom plate and the lid plate of the well are constituted by solid scintillators.

Further, the present invention is characterized in that at least one of the bottom plate and the cover plate has a light transmitting property, and a side peripheral wall of the suction space is non-transparent.

Further, in the present invention, the sample receiving port is formed near an edge of the top plate, and the air hole is located near an edge of the lid plate and on a side opposite to the sample receiving port. It is characterized by being formed.

Further, the present invention is characterized in that a plurality of wells are vertically and horizontally aligned and the arrangement direction of the sample receiving port and the air hole in each of the wells is oblique and parallel. In addition, the present invention provides a liquid radioactive sample
Plate with at least one well
Therefore, the radioactive sample is formed in the well by capillary action.
Pair across a small gap as a suction space to be sucked in
Facing two solid scintillator plates,
Photomultiplier tubes on at least one of the body scintillator plates
Radiation is measured with the light receiving surface of
It is characterized by. In addition, the present invention provides a liquid radioactive sample
Plate with at least one well to be filled
There are two wells facing each other with a small gap
With a radioactive sample filled in the minute gap
And at least one of the two parallel plates is a solid thin plate.
A radiation input from the radioactive sample.
The light generated by the solid scintillator due to
The light is received by the multiplier.

[0014]

According to the above construction, a suction space is formed as a minute gap between the bottom plate and the lid plate of the well, and a sample receiving hole and an air hole are formed in communication with the suction space.
When measuring a sample, first, a tip of a pipette or the like is brought close to the sample receiving hole, and a minute amount of the sample is poured. Then, the sample is sucked into the suction space by the capillary action, and the suction space is filled with the sample. That is, it is possible to smoothly inject the sample into the suction space by utilizing the physical action as the gap in the suction space. In this case, since the air hole communicates with the suction space, the air that originally existed in the suction space is discharged to the outside from the air hole.

Since at least one of the bottom plate and the cover plate is formed of a solid scintillator, radiation emitted from the sample is converted into photons by the solid scintillator,
The radiation from the sample is measured by detecting it with, for example, a photomultiplier tube. Here, by forming both the bottom plate and the lid plate of the well with the solid scintillator, it becomes possible to perform the measurement with the photomultiplier tube from both above and below the plate. In that case, at least one of the bottom plate and the lid plate has light transmittance, while the side peripheral wall of the suction space is non-transparent. That is,
This allows light to be emitted upward or downward, and prevents light from wrapping around to the side.

In forming the sample receiving port and the air hole near the edge of the lid plate, both of them are formed at positions opposite to each other, and the arrangement direction is oblique to improve the arrangement density of the wells. can do. That is, it is possible to keep the sample receiving ports as far away from each other as possible while reducing the distance between the wells. According to such a configuration, contamination and the like can be effectively prevented.

As described above, according to the present invention, since the radiation is measured using the solid scintillator, the problem caused by the liquid scintillator can be solved, and the volume inside the well can be sufficiently reduced. . Further, there is an advantage that the plate itself can be made thin. Furthermore, since the sucked sample is held in the suction space by the surface tension of the sample itself, there is an advantage that scattering of the sample against external vibrations can be effectively prevented.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged view of a main part of a radioactive sample measuring plate according to the present invention. FIG. 4 shows a top view of the plate 100.

In FIG. 1, a well 10 according to the present embodiment includes:
The apparatus has two plastic scintillators (hereinafter, referred to as scintillators) 12 and 14 as a cover plate and a bottom plate, and a suction space 16 into which a sample is sucked is formed between the two scintillators 12 and 14.

FIG. 2 shows a cross section taken along the line II-II ′ shown in FIG.
14 are closely arranged in parallel with each other. 1 and 2
2, two openings 18 and 20 are formed in the edge of the scintillator 12 so as to communicate with the suction space 16. One of the two openings 18 and 20 functions as a sample receiving opening, and the other functions as an air hole. As shown in FIG.
0 is provided on the edge opposite to the scintillator 12. Thereby, when a sample is injected from the opening 18,
The air that is pushed out by the sample when the sample is sucked can be discharged from the opening 20 to the outside.

In this embodiment, each of the two openings 18 and 20 has a crescent shape when viewed from above, but is not limited to this shape.

As shown in FIG. 1, the arrangement direction of the openings 18 and 20 is parallel in each well 10 and is obliquely inclined with respect to the arrangement direction of the wells. As a result, as shown in FIG. 4, the density of the wells 10 can be improved, and in this case, the distance between the openings can be kept as large as possible. This can effectively prevent contamination and the like.

As shown in FIGS. 1 and 2, the two scintillators 12, 14 are fixed to the plate 100 using, for example, an adhesive. Here, the scintillators 12, 14 are made of a transparent member, and the plate 10
0 is made of, for example, a milky member. By configuring the plate 100 with an opaque member in this way, it is possible to prevent the light generated by the scintillators 12 and 14 from wrapping around in the horizontal direction. Of course, in order to more effectively prevent the wraparound, an annular convex portion or the like surrounding the light receiving surface of the photomultiplier tube may be formed.

In this embodiment, the diameter of the suction space 16 is, for example, 6 mm, and the thickness of the suction space 16 is, for example, 1 mm. The diameter of each of the scintillators 12 and 14 is, for example, 7 mm, and the thickness thereof is, for example, 0.5 mm.
It is.

Next, a method for measuring a radioactive sample using the plate 100 of this embodiment will be described.

First, a sample is poured into each well 10 of the plate 100. For example, by bringing the tip opening of the pipette into which the sample has been sucked close to one of the openings 18 and 20 and then pushing out the sample in a small amount from the pipette, the sample is sucked into the suction space 16. That is, the sample is smoothly filled into the suction space 16 by the capillary phenomenon. In this case, the air pushed out of the well 10 by the sample is discharged to the outside from the other opening.

After the filling of each well with a sample is completed, radiation is measured using a photomultiplier tube (PMT). That is, as shown in FIG. 3 showing a section taken along the line III-III ′ of FIG. 1, the light receiving surface of the photomultiplier tube is approached from above and below each well 10 and the photoelectron is located at a position where the light receiving surface is in contact with the surfaces of the scintillators 12 and 14. Position the intensifier. The radiation emitted from the sample 102 is converted into photons by the scintillators 12, 14, and the photons are detected by the photomultiplier. The output signal is output to the coincidence counting circuit 104, and the radiation is counted only when the radiation is simultaneously detected by the two photomultiplier tubes. As a result, the influence of thermal noise or the like generated randomly inside each photomultiplier tube can be reduced.

After measuring the radiation for a predetermined time, the two photomultiplier tubes are moved to measure the radiation in the next well 10. Of course, a plurality of pairs of photomultiplier tubes may be arranged in accordance with the pitch of the wells, and the simultaneous measurement may be performed on the plurality of wells.

After radiation measurement is performed on all the wells 10 formed on the plate 100, the plate 100 is discarded. In this embodiment,
Since the liquid scintillator is not used, it is easy to handle the waste.

In this embodiment, both the cover plate and the bottom plate of the well 10 are made of a plastic scintillator, but it is needless to say that only one of them may be made of a plastic scintillator. However, by forming both of them with plastic scintillators, measurement with high sensitivity is possible. The shape of the scintillators 12, 14 is not limited to a circle, but may be, for example, a rectangle. However, since the shape of the light receiving surface of the photomultiplier tube is generally circular, it is desirable to form the light receiving surface in a circular shape.

In this embodiment, the two openings 18 and 20 are formed on the same side of the plate, but they may be formed on opposite sides. The lower surface of the scintillator 14 may be a reflection surface, or a reflection plate may be provided in place of the scintillator 14 to detect radiation on the upper surface of the scintillator 12.

[0033]

As described above, according to the present invention, since the liquid scintillator is not used, the problem caused by the liquid scintillator can be solved. In addition, since the volume of the well can be reduced, a valuable sample can be effectively used. In addition, since the plate can be made extremely thin, the handleability of the plate can be improved. Furthermore,
Even if an external impact occurs, the sample is securely held in the well, so that scattering of the sample can be effectively prevented.

Further, by making the arrangement direction of the sample receiving port and the air hole obliquely parallel, the density of wells on the plate can be improved.

Further, according to the present invention, since the light receiving surface of the photomultiplier can be brought very close to the well, there is an effect that the measurement sensitivity can be improved.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of a radioactive sample measurement plate according to the present invention.

FIG. 2 is a sectional view showing a II-II ′ section shown in FIG. 1;

FIG. 3 is a cross-sectional view illustrating a line III-III ′ illustrated in FIG. 1 and a diagram illustrating a coincidence circuit;

FIG. 4 is an overall configuration diagram of a plate 100.

[Explanation of symbols]

 Reference Signs List 10 well 12,14 plastic scintillator 16 suction space 18,20 opening 100 plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-113872 (JP, A) JP-A-6-186339 (JP, A) JP-A-7-104067 (JP, A) JP-A-59-1984 218975 (JP, A) Japanese Utility Model Showa 62-44289 (JP, U) Japanese Utility Model Application Hei 7-2955 (JP, U) Special Table Hei 3-500211 (JP, A) Special Table Hei 7-509405 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01T 1/20 G01N 1/28 G01N 23/10 G01T 1/203

Claims (7)

(57) [Claims] 1. A plate wells radioactive sample is sucked, which is at least one formation of a liquid, it said well is formed as a small gap between the bottom plate and the cover plate, radioactive trial
A suction space into which the material is sucked, a sample receiving port communicating with the suction space, and an air hole communicating with the suction space, and at least one of the bottom plate and the cover plate of the well is formed of a solid scintillator. A radioactive sample measurement plate, characterized in that: 2. The plate according to claim 1, wherein both the bottom plate and the lid plate of the well are formed of a solid scintillator. 3. The radioactive sample according to claim 1, wherein at least one of the bottom plate and the lid plate has a light-transmitting property, and a side peripheral wall of the suction space is non-transparent. Measurement plate. 4. The plate according to claim 3, wherein the sample receiving port is formed near an edge of the top plate, and the air hole is near an edge of the lid plate and is opposite to the sample receiving port. A radioactive sample measurement plate formed at a side position. 5. The plate according to claim 4, wherein a plurality of wells are formed vertically and horizontally, and the arrangement direction of the sample receiving port and the air holes in each of the wells is oblique and parallel. Radioactive sample measurement plate. 6. A well into which a liquid radioactive sample is sucked.
Wherein at least one plate is formed, wherein the well is sucked by a radioactive sample by capillary action.
Facing each other with a small gap as a suction space
It has two solid scintillator plates, and at least one of the two solid scintillator plates
Radiation measurement with the photomultiplier tube light receiving surface
A plate for measuring a radioactive sample, wherein the plate is made. 7. A well in which a liquid radioactive sample is filled.
At least one plate, wherein the wells are two parallel plates facing each other with a small gap therebetween.
A radioactive sample is filled in the minute gap, and at least one of the two parallel plates is a solid scintillator.
The solid sampler by the incidence of radiation from the radioactive sample.
The light generated by the scintillator is received by the photomultiplier tube
A radioactive sample measurement plate, characterized in that: