JPH0517671Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scintillation detector, particularly to a scintillation detector for measuring radiation in a sample for radioimmunoassay (RIA) or the like.

[Prior Art] Radioimmunoassay (hereinafter referred to as RIA) is a well-known method for measuring trace components through a reaction using the patient's serum without administering RI (radioisotope) to the patient. It is widely used because it allows extremely sensitive measurements using a trace amount of RI.

NaI is used as a radiation detector in RIA.
A scintillation detector using a (Tl) scintillator is generally used, and as shown in Figure 3, this scintillation detector has a well-shaped hole in the scintillator. A device is used to house and measure a test tube containing a sample, and is divided into a well type [Fig. 3a] and a through-hole type [Fig. 3b].

This well-type detector has a test tube placed in a well hole 12 provided in a NaI (Tl) scintillator 10.
4 can be inserted. and,
A photomultiplier tube 18 is provided on the bottom surface 16 of the NaI (Tl) scintillator 10. On the other hand, in the through-hole type device, the photomultiplier tube 18 is made of NaI (Tl).
They are provided on one side 17 of the scintillator 10, and both efficiently collect the scintillator light emitted by the radiation in the sample to measure the radiation dose in the sample.

Therefore, trace components in a sample can be accurately analyzed from the radiation dose measured by such a scintillation detector.

[Problems to be solved by the invention] Problems of the prior art In the radiation detector described above, a test tube as shown in FIG. 4 is used, and this test tube has a diameter of, for example, 16mm and its height is 50~
The size is about 120 mm and the capacity is about 3 to 10 cc.

As shown in FIG. 5, the sample 20 used in RIA is, for example, a ball-shaped object with a diameter of 6 mm or a precipitate with a thickness of 1 mm or less in a liquid. Radiation measurement will be performed on a small amount of sample 20 existing only at the bottom.

However, since pretreatment of the sample, such as dispensing, incubation, and B/F separation, is performed in the same test tube, radioactive substances that are unnecessary for the final measurement may remain and adhere to the inner wall of the test tube. Even if this amount is small, the amount of the sample 20 itself is also small, so there is a problem that it has a large influence on the measurement and causes a measurement error.

Purpose of the invention The present invention was devised to solve the above-mentioned conventional problems, and its purpose is to create a scintillation detector that does not cause measurement errors due to residual radioactive substances adhering to the inner walls of test tubes. Our goal is to provide the following.

[Means and actions for solving the problems] In order to achieve the above object, the present invention measures radiation in the sample by storing a test tube containing a sample in a well hole formed in a scintillator. In a well-type scintillation detector, a radiation shielding tube is detachably inserted into the scintillator well hole and is attached to the upper edge of the well hole by a retaining collar provided at the top. It is set to maintain a predetermined gap between the test tube and the bottom of the well, and is characterized by a radiation shielding tube that shields only the radiation from residual radioactive substances attached to the inner wall of the test tube above the sample.

With the above configuration, unless the entire scintillator well hole is used as a light emitter for radiation detection, the radiation shielding tube can be inserted into the well hole, and the residue attached to the test tube during sample pretreatment can be removed. Blocks radiation emitted from radioactive materials and prevents it from reaching the scintillator. Since this radiation shielding cylinder maintains a predetermined gap with the well bottom,
Only the RI radiation dose contained only in the sample can reach the scintillator.

[Embodiments] Preferred embodiments of the present invention will be described below based on the drawings. Note that the same members as those in the conventional device are given the same reference numerals and their explanations will be omitted.

FIG. 1 shows a well-type scintillation detector, in which a photomultiplier tube 18 is connected to the bottom surface 16 of a NaI (Tl) scintillator 10 having well holes 12. A test tube as shown in the figure is inserted into the well hole 12, and a measurement sample 20 is inserted into the well hole 12.
is injected into the bottom of the test tube 14.

A feature of the present invention is to shield radiation from residual radioactive substances adhering to the inner wall of the test tube, and for this purpose a radiation shielding tube 22 is inserted into the well hole 12. This radiation shielding tube 22
As shown in FIG.
(Tl) It is formed so that it can be freely taken in and out of the scintillator 10. The radiation shielding tube 22 has a length that maintains a predetermined distance from the well bottom 12A when inserted into the well hole 12, that is, a distance that does not shield radiation emitted from the sample 20.

Therefore, only the radiation emitted from the residual radioactive material attached to the inner wall of the test tube 14 can be effectively shielded, and the radiation only in the sample to be measured can be blocked without mixing with the radiation emitted from the sample 20. It becomes possible to measure accurately.

In addition, since this radiation shielding tube 22 can be detachably inserted into and removed from the well hole 12, NaI
(Tl) When the entire well hole 12 of the scintillator 10 is used as a light emitter for radiation detection, it is possible to easily remove the radiation shielding tube 22 and perform radiation measurement.

Although it is desirable to use lead as the most effective shielding material for the radiation shielding tube 22, since most of the RI nuclides used in RIA are low-energy substances such as 125 _I , it is preferable to use materials such as stainless steel or brass. These materials can provide sufficient radiation shielding.

[Effects of the invention] As explained above, according to the invention, a radiation shielding tube is installed in the scintillator well hole to shield only the radiation from residual radioactive substances attached to the test tube, thereby eliminating unnecessary radiation for measurement. It is possible to prevent contamination and accurately measure the amount of RI in the sample.
It becomes possible to analyze trace components in a sample with high precision.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a preferred embodiment of the well-type scintillation detector according to the present invention, Fig. 2 is an explanatory diagram showing a radiation shielding cylinder, and Fig. 3 is an explanatory diagram showing a conventional well-type scintillation detector. It is an explanatory diagram,
a shows a well type, b shows an explanatory diagram showing a through-hole type, FIG. 4 shows an explanatory diagram showing the size of the test tube,
FIG. 5 is an explanatory diagram showing the state of a sample injected into a test tube. 10... NaI (Tl) scintillator, 12... Well hole, 14... Test tube, 18... Photomultiplier tube,
20... Sample, 22... Radiation shielding cylinder, 24...
Hanging brim.

Claims (1)

[Scope of utility model registration request] In a well-type scintillation detector that measures radiation during the test by storing a test tube containing a sample in a well hole formed in a scintillator, the scintillator well hole is connected to the well hole by a hanging collar provided at the top of the scintillator well hole. A radiation shielding tube that is attached to the upper edge is detachably inserted, and the radiation shielding tube is set to maintain a predetermined gap with the bottom of the well when inserted into the well hole. A well-type scintillation detector that is characterized by blocking only radiation from residual radioactive substances attached to the inner wall of a test tube.