JP3831724B2 - Radioactive chemical generator - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a radioactive chemical production apparatus provided with a shielding member for a radioactive substance, particularly a shielding member used for a medical radioactive chemical transport container or the like.

There are various shapes and materials of containers equipped with radioactive material shielding members, but transport vials and ampoules filled with radioactive chemicals used for medical purposes, so-called prefilled syringes filled with chemicals, etc. In general, a shielding member used in a radioactive chemical transport container for storage, a so-called generator or a radioactive chemical generating apparatus called a generator, and the like using only lead as a radiation shielding material is generally known (for example, Patent Documents 1 to 3). 3).
At present, these shielding members ensure the shielding ability by increasing the thickness of the shielding body when the radioactivity of the radioactive material to be stored increases. Moreover, in order to ensure a shielding capability, it may be accommodated in a larger shielding member and transported.
JP 52-37697 A JP 54-101094 A JP-A-2-95380

However, when the thickness of the shielding body is increased, the outer shape of the shielding member is increased and the weight is also increased, which hinders handling of the container provided with the shielding member. Further, when a normal shielding member is accommodated in a larger shielding member, there is a drawback that the weight and volume are greatly increased.
If tungsten, which has a higher radiation shielding ability than lead, is used as the shielding material, the shielding member can be made lighter and smaller than lead, but tungsten is more expensive than lead. It was uneconomical to make all of the shielding body of tungsten, and it was not used for a large shielding member.
Furthermore, it is both cumbersome and uneconomical to produce a number of shielding members having different shielding capabilities depending on the type of radioactive material to be stored and the difference in radioactivity intensity.

  The present invention has been made to solve the above-described problems, and while maintaining the same shielding ability as the conventional one, it can achieve a reduction in size and weight, or if the same size, the shielding ability can be achieved. For radioactive materials that can be improved, can store radioactive materials with higher radioactivity, can be manufactured easily, and can change the shielding ability according to the type of radioactive material to be stored and changes in radioactivity It aims at providing the radioactive chemical | medical solution production | generation apparatus which uses a shielding member.

In order to achieve the above object, the present invention is configured as follows.
In addition, the radioactive chemical generation apparatus according to the first aspect of the present invention includes a container portion having a concave portion for containing a radioactive substance and containing lead as a main material, an opening portion of the concave portion being attached to the container portion, and the lead being mainly used. A radioactive chemical generator comprising a radioactive substance shielding member having a lid as a material,
In the container part,
A shield made of a material other than lead, and a bottom shield made of tungsten disposed at the bottom of the recess;
A shield made of a material other than lead and forming a side portion of the recess located in a direction orthogonal to the axial direction of the recess, which is 60% of the total length of the recess from the upper surface of the opening. Side shields extending in the axial direction in length and made of tungsten;
A mold for forming the recess when the container portion is cast by extending along the axial direction of the recess to form a side portion of the recess, connecting the side shield and the bottom shield, and casting the container portion. A connecting member that prevents the lead from flowing into the gap between the cylindrical portion and the side shield covering the circumferential surface of the cylindrical portion;
The recess contains a column containing the parent radionuclide,
An eluent supply means connected to the column for supplying an eluent to the column;
A radiochemical solution discharging means for discharging a radioactive solution containing a daughter radionuclide connected to the column and eluted from the column from the column;
The lid portion is provided with a shield made of tungsten and disposed in a portion facing the opening portion of the recess, and the other portion of the lid portion is made of lead.
It is characterized by that.

  Moreover, it can also comprise so that the parent radionuclide accommodated in the said column may be molybdenum-99.

  Further, the side shield made of tungsten and the shield of the lid part are formed independently of the lead part in the container part, and according to the radioactivity of the radioactive substance. It can also be configured such that the shape and material can be exchanged.

In addition, the present applicant can reduce the weight of the container while keeping the leakage dose from the container the same as the conventional standard by combining two or more types of radiation shielding materials having different shielding capabilities. The shielding member for the found out radioactive chemical generator was completed.
The shielding member for radioactive substance in the other aspect of the present invention is a shielding member for radioactive substance having a container part having a recess for storing the radioactive substance and a lid part covering the opening part of the recess and attached to the container part. There,
The container portion includes a first shield and a second shield having a higher radiation shielding ability than the first shield, and at least a part of a region forming the concave portion is configured by the second shield. The lid is composed of at least one type of radiation shielding member.

According to still another aspect of the present invention, there is provided a radioactive chemical solution generating apparatus, comprising: a container part having a recess for storing a radioactive substance; and a shielding for radioactive substance having a cover part covering the opening part of the recess and attached to the container part. A radiopharmaceutical generating device provided with a member,
A bottom shield disposed at the bottom of the recess in the container portion, and a shield that forms a side of the recess positioned in a direction orthogonal to the axial direction of the recess, and is less than the full length or the full length of the recess. The side shield that extends in the axial direction by length, and the shield that arranges the opening portion of the recess in the lid portion in the facing portion are made of tungsten, and the other portions are made of lead. ,And,
The recess contains a column containing a parent radionuclide, and includes an eluent supply means connected to the column for supplying an eluent to the column, and a daughter radionuclide connected to the column and eluted from the column. And a radioactive chemical solution discharging means for discharging the radioactive solution from the column.

According to still another aspect of the present invention, there is provided a method of manufacturing a shielding member for a radioactive substance, which includes a container part having a concave part that stores the radioactive substance, and a lid part that covers the opening part of the concave part and is attached to the container part. In the manufacturing method of the radioactive substance shielding member, the container portion is
The side part shielding which prepares the casting_mold | template corresponding to the external shape of the said container part, and the length of the convex part for shape | molding the said recessed part is the length which does not satisfy the full length of the said convex part along the axial direction of the said convex part. The body is covered, the tip of the convex is covered with a bottom shield, and the side surface of the convex between the side shield and the bottom shield along the axial direction of the convex is a connecting member. After the covering, the side shield, the bottom shield, and the connecting member are manufactured by pouring into the mold a radiation shielding material having a melting temperature that does not melt.

  The radioactive chemical generator in the first aspect of the present invention includes a radioactive substance shielding member having a container part and a lid part. The container portion is made of tungsten having a higher radiation shielding ability than lead while the bottom shield and the side shield are made of lead as a main material. Therefore, weight reduction and size reduction of a radioactive chemical | medical solution production | generation apparatus can be achieved, maintaining the same shielding capability as before. Moreover, when it consists of the same magnitude | size as the conventional radioactive chemical | medical-solution production | generation apparatus, the shielding capability of a radiation can be increased and it becomes possible to increase the radioactivity of the radioactive substance accommodated in the said recessed part.

  Moreover, the said container part has a connection member. When the container part is cast, the connecting member is a lead between the cylindrical part which is a convex mold for forming the concave part and the side shield disposed so as to cover the peripheral surface of the cylindrical part. Is prevented from flowing in. Therefore, the connecting member facilitates release of the cast container part and the cylindrical part. Therefore, it is possible to facilitate the production of the radioactive chemical solution generator.

  Further, the side shield and the lid shield can be exchanged as an independent molded body with respect to the lead portion of the container, so that the type of radioactive substance stored in the recess and the amount of radioactivity can be changed. Thus, the thickness and material of the side shield and the lid shield can be replaced with a suitably selected shield. Therefore, the versatility of the radioactive substance shielding member is increased and it is economical.

A radioactive chemical solution generating apparatus having a radioactive substance shielding member according to an embodiment of the present invention will be described below with reference to the drawings. In addition, in each figure, the common code | symbol is attached | subjected about the common member.
The shielding member has a lid part and a container part made of a shield made of a radiation shielding material, the lid part is made of one or a plurality of radiation shielding materials, and the container part is made of a plurality of radiation shielding materials. It is the shielding member for radioactive materials characterized.
In the radioactive substance shielding member, at least one of the lid part and the container part is composed of a plurality of shielding bodies made of two or more types of radiation shielding materials having different shielding capabilities.
Furthermore, the shielding member for the radioactive substance is made of a shielding body made of a radiation shielding material having a higher shielding ability and a radiation shielding material having a shielding ability lower than that of the radiation shielding material having a higher shielding ability inside the container. The shield is arranged on the outside thereof.
Shielding member for radioactive material using at least two kinds of radiation shielding materials selected from lead, tungsten and deteriorated uranium as radiation shielding materials having different shielding ability, especially tungsten and lead or a combination of deteriorated uranium and lead The shielding member for radioactive material is suitable.
The radioactive substance shielding member includes one or all of the inner shielding bodies forming at least one of the lid portion and the container portion, which are independent molded bodies, and may be replaceable. Some or all of the plurality of shields forming at least one of the container portions may be integrally formed.
Radiopharmaceutical liquid transport container provided with a radioactive chemical liquid container storage part, radioactive chemical shielding apparatus including a column containing at least a parent radionuclide in a radioactive substance shielding member, an eluent supply means, and a radioactive chemical liquid discharge means Is a preferred embodiment.
Further, in another embodiment, a radiation shielding material is prepared in which a mold corresponding to the container portion of the radioactive substance shielding member is prepared, and a convex portion corresponding to a space for accommodating the radioactive substance in the mold is injected into the mold later. After coating with a shield made in advance with a radiation shielding material having a melting temperature sufficiently higher than that, a radiation shielding material having a melting temperature lower than that of the radiation shielding material is injected into the mold, and integrated casting It is related with the manufacturing method of the container part of the said shielding member for radioactive substances characterized.

The radioactive material shielding member may be applied to the radioactive material contained therein having a radioactivity of several mCi to several tens of mCi, but the radioactivity is low by combining a shield made of a plurality of radiation shielding materials. Making a shielding member for a radioactive substance has few merits such as downsizing and weight reduction in terms of manufacturing complexity and cost. Therefore, the object can be achieved more effectively by applying the shielding member to a shielding member that stores a radioactive substance having a radioactivity of several hundred mCi or more, for example.
As shown in FIG. 1, a medical radioactive chemical generator (technetium-99m generator) containing molybdenum-99 eluting 100-300 mCi (3.7-11.1 GBq) of technetium-99m chemical on the day of the test. A shielding member for 100 is one of the preferred embodiments.

  As the radiation shielding material used for the shielding member, various materials such as lead, tungsten, deteriorated uranium, boron steel, boron stainless steel, cadmium, stainless steel, concrete, plastic, etc. are conceivable, and are stored in the shielding member. The shielding material is appropriately selected according to the type of radioactive substance and the amount of radioactivity. However, as a shielding material used in a radioactive chemical solution transport container or a radioactive chemical solution generator for medical use, a combination of two or more of γ-ray shielding materials such as lead, tungsten and depleted uranium, that is, lead and tungsten. Alternatively, a combination of lead and deteriorated uranium is preferable because of its good shielding ability. In particular, tungsten and lead are used as shielding materials for shielding members for medical radiopharmaceutical generators and medical radiopharmaceutical transport containers in terms of ease of manufacture, ease of handling, cost, etc. It is desirable to use

Lead density is 11.3 g / cm ³ , tungsten density is 19.3 g / cm ³ , and degraded uranium density is 19.0 g / cm ³ , so the shielding ability is reduced from the viewpoint of weight reduction of shielding members. It is desirable to place high tungsten or depleted uranium inside the shielding member.

FIG. 9 shows the relationship between the tungsten and lead thicknesses and the leakage dose.
As is clear from the AB line shown in FIG. 9, when the leakage dose is constant, the thickness of lead can be reduced by increasing the thickness of tungsten.
Further, as is apparent from the CD line, when the thickness of the shield combining tungsten and lead is made constant, the leakage dose can be reduced by increasing the thickness of tungsten.

  In addition, when charged particles are emitted from a radiation source, it is effective to first shield the radiation source with a substance having a low density in order to suppress generation of braking X-rays. In addition, some shielding materials are soft and vulnerable to impacts, such as lead, and have metal toxicity. Considering the ease of handling such as transportation, shielding materials such as deteriorated uranium and lead In some cases, it is desirable to coat the surface and exposed surface with a material such as plastic.

  Further, as will be described in detail later, the inner shield and other shields are formed independently so that one or all of the inner shields of the shield members can be exchanged, that is, attached or detached. It is preferable to use in combination as a body. In this case, by changing the thickness of the shielding body that forms the housing part or selecting the type of radiation shielding material according to the type of radioactive substance and the amount of radioactivity stored in the housing part in the shielding member The radiation dose from the radioactive substance shielding member can be adjusted and the weight of the radioactive substance shielding member can be reduced without changing the external dimensions of the radioactive substance shielding member. Therefore, even if the kind of radioactive substance contained in the radioactive substance shielding member or the amount of radioactivity changes, one radioactive substance shielding member can be used, which increases the versatility and is economically advantageous.

Hereinafter, the radioactive substance shielding member will be described in detail with reference to the drawings, taking as an example the radioactive substance shielding member used in the technetium-99m generator corresponding to the radioactive chemical solution generator. 3 is a plan view of the radioactive substance shielding member 101 shown in FIGS. 1 and 2, and the radioactive substance shielding member 101 shown in FIGS. 1 and 2 has a cross section taken along line XV-XV shown in FIG. Show.
The radiochemical solution generation apparatus (technetium-99m generator) 100 shown in FIG. 1 has a radioactive radionuclide on a radioactive substance shielding member 101 composed of a cover part 4 and a container part 5 made of a shield made of a radiation shielding material. An alumina column 1 on which molybdenum-99 is adsorbed, an eluent supply means 8 having an eluent supply port 8a to which a physiological saline vial 2 is attached, and a technetium-99m solution that is a daughter nuclide eluted from the molybdenum-99 And a radioactive chemical liquid discharge means 9 having an eluent outlet 9a for mounting a vacuum vial 3 for collecting the liquid.

  The container part 5 has a substantially cylindrical shape, and is formed in a central part of the container part 5 at a first recessed part 6 having a shallow depth in the axial direction of the container part 5 and a bottom part 6 a of the first recessed part 6. And a second recess 7 for housing the alumina column 1 having a diameter smaller than that of the first recess 6 and deep in the axial direction. A peripheral portion 5b of the second recess 7 is a cylindrical tungsten shield 51 having a predetermined length and a predetermined thickness along the axial direction of the second recess 7 from the bottom surface of the bottom 6a. Molded. The tungsten shield 51 corresponds to an embodiment of the second shield and the side shield. The tungsten shield 51 may be formed over the entire length of the second recess 7 in the axial direction, but in this embodiment, the alumina column 1 in which molybdenum-99 is adsorbed only on a relatively upper part of the alumina column 1. Therefore, considering the shielding ability and the weight, it extends from the bottom surface of the bottom portion 6a to a length of about 60 to 70% of the entire length of the second recess 7 as shown in the figure. The bottom 5c of the second recess 7 has a predetermined thickness in the axial direction, and a tungsten shield 52 is provided. In addition, the tungsten shielding body 52 corresponds as an example of one aspect of the bottom shielding body. Further, the tungsten shield 52 corresponds to an example of one embodiment of the second shield. The remaining portion 5a of the container portion 5 excluding the peripheral portion 5b and the bottom portion 5c is formed of lead. The lead portion 5a, the surrounding portion 5b made of tungsten, and the bottom portion 5c made of tungsten constitute the container portion 5. Further, one embodiment of the first shield corresponds to the lead portion 5a.

  In the second recess 7, the alumina column 1 is appropriately supported and accommodated by a protrusion (not shown) provided on the inner peripheral surface 51 a of the tungsten shield 51, for example. As shown in the figure, the alumina column 1 includes an eluent supply means 8 for supplying a physiological saline solution from the physiological saline vial 2 to the alumina column 1 and a technetium-99m solution eluted with the supplied eluent. The radioactive chemical solution discharging means 9 leading to the vacuum vial 3 is connected.

The lid 4 includes an outer shield 4a made of lead, an inner shield 4b made of lead, and a tungsten shield 41 made of tungsten, and the inner shield 4b is fitted into the first recess 6. In addition, the said outer side shield 4a and the said inner side shield 4b are equivalent as an example of a 3rd shield, and the said tungsten shield 41 is equivalent as an example of a 4th shield. In the inner shield 4b, a space 6b in which the eluent supply means 8 and the radioactive chemical liquid discharge means 9 extend is formed. In addition, a cylindrical recess 4c is formed on the bottom surface 4d of the inner shield 4b facing the opening 7a of the second recess 7 in the inner shield 4b, and a tungsten shield 41 is fitted in the recess 4c. Combined. In addition, parts other than the recessed part 4c in the inner side shield 4b are shape | molded with lead.
The outer shield 4a has a substantially disk shape that covers the upper surface of the container 5 in which the inner shield 4b is fitted in the first recess 6, and the eluent supply means 8 and the radioactive chemical liquid discharge means 9 extend. Spaces 42 and 43 in which these can extend are formed in the portion.

  The lid portion 4 and the container portion 5 are accommodated in a plastic outer container 10 having a generally box shape. In the outer container 10, the container upper part 10a to which the physiological saline vial 2 and the vacuum vial 3 can be attached and the container lower part 10b in which the lid part 4 and the container part 5 are accommodated are engaged means (not shown). Are detachably connected.

  In the present embodiment, the lid portion 4 has a substantially disc shape, the container portion 5 has a substantially cylindrical shape, the tungsten shield 41 of the recess 4c has a disc shape, and the first recess 6 and the second recess. 7 has a circular shape, the tungsten shield 51 has a cylindrical shape, and the tungsten shield 52 has a disk shape, but each member is not limited to these shapes. For example, the outer shape of the lid part 4 and the container part 5 is a polygonal shape, the tungsten shield 51 is a polygonal cylinder, or the tungsten shield 51 and the tungsten shield 52 are integrally formed in a cup shape. Alternatively, the recess 4c and the bottom 5c may have a shape other than a disk.

  In using such a radioactive drug solution generating apparatus 100, first, the physiological saline vial 2 is attached to the eluent supply port 8a of the eluent supply means 8, and then a vacuum is applied to the eluent outlet 9a of the radioactive drug solution discharge means 9. A vial 3 is attached. With this configuration, due to the vacuum pressure of the vacuum vial 3, the physiological saline in the physiological saline vial 2 passes through the alumina column 1 through the eluent supply means 8, and the daughter eluted in the alumina column 1. A solution containing the radionuclide technetium-99m is collected in the vacuum vial 3 through the radioactive chemical solution discharging means 9.

  Next, the relationship between the thickness and weight of the shield by combining two types of radiation shielding materials will be described by taking as an example a shielding member having the structure shown in the above-described radioactive chemical solution generating apparatus 100 (Technetium-99m generator). That is, based on the leakage dose in the first measurement container in which 200 mCi of radioactive molybdenum-99 is housed in the alumina column 1 and the lid part and the container part corresponding to the lid part 4 and the container part 5 are made of only lead. The relationship between the thickness and weight of the shielding member by a combination of a lead shielding body and a tungsten shielding body that secures the same shielding ability was examined. The results are shown in Table 1. In Table 1, “top surface”, “side surface”, and “bottom surface” for lead correspond to “I”, “II”, and “III” shown in FIG. 1, respectively, and “top surface”, “side surface” for tungsten. "And" bottom surface "correspond to" IV "," V ", and" VI "shown in FIG. 1, respectively.

As is clear from Table 1, the fifth measurement container having a tungsten thickness of 30 mm has a smaller outer shape and weight than the first measurement container in which the lid and the container are all made of lead. Is also lighter. In addition, when all the cover parts and the container parts are made of tungsten, it becomes expensive.
On the other hand, when the lead and tungsten shields are combined, as in the second measurement container to the fourth measurement container, the cover and the container are all made of tungsten, which is further than the fifth measurement container. It became possible to reduce the weight. That is, the first measuring container weighs about 10 kg, but the second measuring container to the fourth measuring container are reduced in weight to about 7.2 to 7.6 kg. Therefore, the radioactive solution generator using such a radioactive substance shielding member is easy to carry and the like compared to the conventional product. From these facts, it was confirmed that combining two kinds of radiation shielding materials is effective for securing shielding ability and reducing weight.

  Further, the lead thickness in the first measurement container is reduced to 10 mm from 40 mm to 30 mm, and 10 mm thick tungsten is provided in the peripheral portion 5b shown in FIG. A container was prepared. The relationship between radioactivity and leakage dose was examined for the eleventh measurement container and the first measurement container. As shown in FIG. 10, the leakage dose of the eleventh measurement container was about 60% of the lead-only technetium-99m generator corresponding to the first measurement container. Further, if the leakage dose in the eleventh measurement container is equal to the leakage dose in the first measurement container, the eleventh measurement container is about 1.5 times as much in radioactivity as the first measurement container. High radioactive material can be stored.

Next, in the case where the radioactivity in the alumina column 1 is increased to 300 mCi (11.1 GBq), which is 1.5 times 200 mCi (7.4 GBq), the sixth measurement capable of ensuring the same shielding ability as the first measurement container. Table 2 shows the thickness, weight, and weight ratio of each shield part in the container for measurement or the tenth measurement container.
In the sixth measurement container in which the entire shielding body is made of lead, it is necessary to increase the thickness of the shielding body in order to ensure the shielding ability. As a result, the weight of the sixth measurement container is the same as that for the first measurement. About 1.2 times the container, that is, about 12 kg.
On the other hand, when a 10 mm thick tungsten shield and lead shield are combined as in the seventh measurement container, the thickness of the shield and the leakage dose (shielding ability) are the same as the first measurement container. The weight is about 80% of the weight of the sixth measurement container in which all the shields are made of lead. Therefore, a radioactive substance having higher radioactivity can be configured with a shielding member having the same shielding ability as that of the conventional product and a weight equivalent to that of the conventional product.

  From this, it was confirmed that the combination of two types of radiation shielding materials, tungsten and lead, is effective even in the case of improving the shielding ability, ensuring a certain shielding ability and increasing the amount of stored radiation. It was.

Moreover, in the radioactive chemical generator 100 shown in FIG. 1, in the lid part 4 and the container part 5 of the present embodiment, as described above, the peripheral part 5b of the second recess 7 is simply cylindrical, and its diameter is As shown in the drawing, since the diameter of the inner shield 4b is smaller than that of the inner shield 4b, the tungsten shield 51 in the peripheral portion 5b can be pulled out in the axial direction of the second recess 7 and is shielded thinner than the shield thickness of the tungsten shield 51. It can be replaced with another member such as a thick tungsten material or a member made of another material.
In addition, the tungsten shield 41 fitted in the recess 4c of the inner shield 4b is disc-shaped and is slightly protruded from the bottom surface 4d, so that it can be replaced with a thin shield. The weight can be reduced without changing the outer diameter of the inner shield 4b.
By making the shields 51 and 41 provided in the peripheral portion 5b and the concave portion 4c exchangeable in this way, when the radioactivity stored in the second concave portion 7 is low, the material of the shield in the peripheral portion 5b is, for example, When lead is used and the radioactivity is high, the shielding thickness of the lead shield can be increased, or the material can be tungsten. Further, when the radioactivity is higher, the shielding thickness of the tungsten shielding body can be increased. That is, even if the radioactivity of the radioactive substance stored in the second concave portion 7 changes, the shield of the lead portion 5a of the container part 5 and the outer container 10 may be one kind, which increases convenience and is economical. Further, the shield at the bottom 5c may be replaceable, or the second recess 7 may be formed by a single cup-shaped shield, and the thickness of the cup-shaped shield may be changed, You may change the kind of shielding material.
For example, when the shielding thickness of the shield in the peripheral portion 5b may be thin, a lightweight member such as plastic is inserted between the shield in the peripheral portion 5b and the lead portion 5a to reduce the weight. Also good.
In addition, when it is not necessary to replace the shields as described above, the shields that are separately manufactured may be fixed by a method such as adhesion and integrally molded.
Further, deteriorated uranium may be used in place of tungsten as a shielding material.
Further, as will be described in detail later, if the shielding member in the surrounding portion 5b is made in advance with tungsten or the like, and a shielding member is made by a casting molding method in which a radiation shielding material such as lead is poured into the outer portion 5a and molded integrally. The manufacturing cost can be reduced and the manufacturing can be simplified. This is because the melting temperature of lead is about 300 ° C., whereas the melting temperature of tungsten is about 1800 ° C. Tungsten not only has a high shielding ability but also has a sufficiently high melting temperature compared to lead. It is suitable as an inner shield in the case of.
In addition, the matter regarding the replacement | exchange of a shield and the manufacturing method mentioned above is applicable similarly also to the shielding member for radioactive substances which accommodates the radioactive chemical solution container mentioned later.

Next, as another embodiment of the radioactive chemical solution generating apparatus 100, a radioactive chemical solution generating apparatus 110 as shown in FIG. 2 can be produced. The difference between the radioactive chemical solution generating device 100 and the radioactive chemical solution generating device 110 is that the size of the shield in the concave portion 4c and the bottom portion 5c is changed, and the axial direction of the second concave portion 7 is formed in order to form the second concave portion 7. A connecting member 122 is provided along the screen, and a shield 123 is further provided on the bottom of the container 5. Therefore, in FIG. 1 and FIG. 2, the same code | symbol is attached | subjected about the same component.
The shield 120 corresponding to the shield in the recess 4c has an outer diameter XI that is somewhat larger than the inner diameter of the second recess 7 and a thickness VII in the axial direction of the second recess 7 compared to the shield 41 in the recess 4c. Has increased. The shield 121 corresponding to the shield 52 in the bottom portion 5 c has an outer diameter X that is larger than the inner diameter of the second recess 7. In the present embodiment, the thickness VII of the shield 120 exceeds the thickness VIII of the shield 51 in the peripheral portion 5b. The outer diameter X of the shield 121 is substantially equal to the outer diameter of the shield 51 in the peripheral portion 5b, and the thickness IX is substantially equal to the thickness VIII. The reason why the outer diameter X of the shield 121 is made larger than the inner diameter of the shield 51 is to facilitate the manufacture of the shielding member in a manufacturing method as described later.
Specifically, the outer diameter XI of the shield 120 is 18 mm, the thickness VII is 16 mm, the thickness VIII of the shield 51 is 10 mm, the length XII is 50 mm, and the outer diameter of the shield 121 is. X is 35 mm and thickness IX is 11 mm.
The connecting member 122 is a stainless steel pipe having an inner diameter equal to the inner diameter of the second recess 7, and connects the bottom surface 124 of the shield of the peripheral portion 5 b and the upper surface 125 of the shield 121. And coaxially arranged. Accordingly, the second recess 7 is formed by the shield 51, the connecting member 122, and the shield 121 in the surrounding portion 5 b.

Next, the manufacturing method of a shielding member is demonstrated taking the radioactive chemical production apparatus 100,110 mentioned above as an example.
First, as shown in FIG. 5, a mold 21 for molding the container part 5 of the radioactive substance shielding member in the radioactive chemical generator 100 has an inverted T-shape in the recess 24 for forming the lead part 5a. A core pin 22 having a cross section is arranged. The core pin 22 includes a disc-shaped portion 25 for molding the first recess 6 and a column portion 26 for molding the second recess 7. The column portion 26 is erected on the disc-shaped portion 25. It is formed integrally with the disk-shaped portion 25. The cylindrical portion 26 is made of tungsten and is fitted with a shield 51 in the peripheral portion 5b, and the shield 52 made of tungsten is attached to the tip portion 26a of the cylindrical portion 26.

  Lead is injected into the mold 21 from the gate 20. As described above, the melting point of tungsten is sufficiently higher than the melting point of lead, so that tungsten is not melted by lead implantation. When the tungsten shield is provided with a length shorter than the total length in the axial direction of the second concave portion 7 from the point of shielding ability, as in the case of the radioactive chemical solution generating apparatus 100, the lead is used. When injected, lead may flow into the slight gap 23 between the peripheral surface 26b of the cylindrical portion 26 and the inner peripheral surface 51a of the shield 51, and the cast product and the cylindrical portion 26 may not be easily separated from each other. .

In order to prevent the formation of the gap 23 into which lead flows, the cylindrical portion 26 may be covered with a tungsten material over its entire length. However, since tungsten is expensive, it is more economical to reduce the amount used as much as possible. It is. Therefore, the portion that does not require the use of tungsten is completely covered with the cylindrical portion 26 using, for example, stainless steel (melting temperature is about 1300 ° C.) that is cheaper than tungsten and has a melting temperature sufficiently higher than that of lead. That's fine. Thus, the radioactive chemical | medical solution production | generation apparatus manufactured with the manufacturing method of the shielding member which prevented generation | occurrence | production of the said clearance gap 23 is equivalent to the shielding member 111 of the radioactive chemical | medical solution generation apparatus 110. In the radioactive chemical generator 110, the stainless steel pipe-shaped connecting member 122 is provided between the bottom surface 124 of the shield 51 and the shield 121 provided at the tip 26a of the cylindrical portion 26 as described above. That is, the mold 31 for molding the container part 5 of the shielding member 111 in the radioactive chemical generator 110 is connected to the cylindrical portion 26 between the shield 151 and the shield 121, as shown in FIG. Member 122 is inserted. With such a configuration, the gap 23 as described above is not formed. Therefore, it is possible to easily release the cast product and the cylindrical portion 26.
After injecting lead from the pouring gate 20 of the mold 31 to form the container part 5 of the radioactive chemical generating apparatus 110, the mold part is opened up and down at the separation part 32, and the container part 5 is removed from the mold. Separately, the lid 4 is manufactured. As shown in FIG. 2, the container part 5 thus formed is housed in an outer container 10, the column 1 and the lid part 4 containing the radioactive parent nuclide, the eluent supply means 8, and the radioactive chemical liquid discharge means 9. Etc. to complete the radioactive chemical generator 110.

Next, a radioactive chemical transport container using the above-described radioactive substance shielding member will be described.
FIG. 7 shows a radiopharmaceutical transport container 60 for storing the vial 63 containing the radiochemical liquid. The radioactive substance shielding member in the radioactive chemical transport container 60 includes a container part 61 and a lid part 62. The container portion 61 has a cylindrical shape, has a concave portion 64 for accommodating the vial 63, and has a cup-shaped tungsten shield 65 made of tungsten, and surrounds the periphery 65 a of the shield 65 and is made of cylindrical lead. The lead shielding body 66 is formed, and the tungsten shielding body 65 is put in a mold and lead is poured into the outside thereof to be molded. The lid 62 includes a disk-shaped tungsten shield 67 that covers the tungsten shield 65 and a lead shield 68 that covers the upper surface 67a and the peripheral surface 67b of the tungsten shield 67. In the container portion 61, the peripheral surface 66 a of the lead shield 66 and the bottom surfaces 65 b and 66 b of the tungsten shield 65 and the lead shield 66 are covered with a plastic outer container 69. The upper surface 68 a and the peripheral surface 68 b of the shield 68 are covered with a plastic outer container 70. By engaging engaging portions 69 a and 70 a provided in the outer containers 69 and 70, the outer containers 69 and 70 are connected, and the vial 63 is fixed and sealed in the recess 64.
In addition, since the structure as described above is made, the tungsten shields 65 and 67 can be replaced, and the shielding member can be reduced in weight without replacing the lead shields 66 and 68 depending on the amount of radioactivity of the radioactive chemical solution. It is possible.

  FIG. 8 shows a radioactive chemical transport container 75 which is another embodiment of the radioactive chemical transport container 60. The radioactive chemical transport container 75 has a structure in which the tungsten shields 65 and 67 in the radioactive chemical transport container 60 are replaced with the depleted uranium shields 76 and 77, and all outer surfaces of the container part 61 and the lid part 62 are made of plastic. It is covered with a container 78. Since the other structure is the same as the structure in the radioactive chemical transport container 60, the description is omitted. In addition, since all the outer surfaces of the radioactive chemical transport container 75 are covered with the outer container 78, the deteriorated uranium shields 76 and 77 cannot be replaced.

  INDUSTRIAL APPLICABILITY The present invention is particularly applicable to a radioactive chemical solution generating apparatus that generates a medical radioactive chemical solution.

It is sectional drawing which shows the structure in the radioactive chemical | medical solution production | generation apparatus which uses the shielding member for radioactive substances which is one Embodiment of this invention, Comprising: About the shielding member for radioactive substances, it is sectional drawing in the XV-XV line | wire shown in FIG. . It is sectional drawing which shows the structure in other embodiment of the radioactive chemical | medical solution production | generation apparatus shown in FIG. It is a top view of the shielding member for radioactive substances of the radioactive chemical | medical solution production | generation apparatus shown in FIG.1 and FIG.2. It is a top view of the radioactive chemical | medical solution production | generation apparatus shown in FIG.1 and FIG.2. It is sectional drawing of the casting_mold | template for demonstrating the manufacturing method of the container part of the radioactive chemical | medical solution production | generation apparatus shown in FIG. It is sectional drawing of the casting_mold | template for demonstrating the manufacturing method of the container part of the radioactive chemical | medical solution production | generation apparatus shown in FIG. It is sectional drawing of the radioactive chemical | medical solution transport container using the shielding member for radioactive substances which is one Embodiment of this invention. It is sectional drawing in other embodiment of the radioactive chemical transport container shown in FIG. It is a graph which shows the relationship between the thickness of tungsten and lead, and a leakage dose. It is a graph which shows the relationship between storage radioactivity and leakage dose.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Alumina column, 4 ... Cover part, 4a ... Outer shielding body, 4b ... Inner shielding body,
4c ... concave part, 5 ... container part, 5a ... lead part, 5b ... peripheral part, 5c ... bottom part,
7 ... second recess, 7a ... opening, 8 ... eluent supply means,
9 ... Radiochemical discharge means,
21 ... mold, 26 ... cylindrical portion, 26a ... tip,
31 ... mold, 41 ... tungsten shield,
51, 52 ... tungsten shield,
DESCRIPTION OF SYMBOLS 100 ... Radioactive-solution production | generation apparatus, 101 ... Shielding member for radioactive substances,
110 ... Radioactive chemical solution generator, 111 ... Radioactive substance shielding member,
120 ... shielding body, 121 ... tungsten shielding body, 122 ... connecting member,
123: Shield.

Claims (3)

A container part (5) having a concave part (7) for containing a radioactive substance and made mainly of lead, and a lid part (5a) covering the opening part (7a) of the concave part and attached to the container part and made of lead as a main material ( 4) a radioactive chemical generator comprising a radioactive substance shielding member comprising:
In the container part,
A shield made of a material other than lead, and a bottom shield (52, 121) made of tungsten and arranged at the bottom (5c) of the recess;
A shield made of a material other than lead and forming a side portion of the recess located in a direction orthogonal to the axial direction of the recess, which is 60% of the total length of the recess from the upper surface of the opening. A side shield (51) extending in the axial direction in length and made of tungsten;
A mold for forming the recess when the container portion is cast by extending along the axial direction of the recess to form a side portion of the recess, connecting the side shield and the bottom shield, and casting the container portion. A connecting member (122) for preventing the inflow of the lead into the gap (23) between the cylindrical portion (26) and the side shield covering the peripheral surface of the cylindrical portion;
In the recess, a column (1) containing a parent radionuclide is stored,
An eluent supply means (8) connected to the column for supplying an eluent to the column;
Radiochemical solution discharge means (9) for discharging a radioactive solution containing a daughter radionuclide connected to the column and eluted from the column from the column,
The lid portion is provided with a shielding body (41) made of tungsten and disposed in a portion (4c) opposed to the opening portion of the recess, and the other portion of the lid portion is made of lead.
A radioactive chemical generator.   The radioactive chemical production apparatus according to claim 1, wherein the parent radionuclide stored in the column is molybdenum-99. The side shield made of tungsten and the shield of the lid are molded bodies independent of the lead in the container part, and have a shape and a shape according to the amount of radioactivity of the radioactive substance. The radioactive chemical generator according to claim 1 or 2, wherein the material is exchangeable.

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