JP5653291B2 - Sealed brachytherapy container - Google Patents

Description

The present invention relates to a sealed brachytherapy container. More particularly, the present invention relates to a container for containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source, preventing leakage of radiation to the outside of the container, and lead. The present invention relates to a sealed brachytherapy container that can reduce or eliminate the environmental pollution problem caused by the above-mentioned characteristics and that is excellent in workability during manufacturing.

One of the cancer treatments is brachytherapy. This is because cancer brachytherapy is performed by implanting a brachytherapy source that emits radiation in the cancer lesion area and / or the surrounding area of the cancer lesion and irradiating the cancer lesion area with radiation emitted from the brachytherapy source. It is a cure that destroys The brachytherapy is widely used particularly for the treatment of prostate cancer (referred to as “prostate cancer brachytherapy”) (for example, see Non-Patent Document 1). In this case, the hermetically brazed beam source (also referred to as “seed”) is a radiation source chemically bonded to a silver short wire in a cylindrical titanium capsule having a length of several millimeters and a diameter of about 1 millimeter. In general, a sealed material of ¹²⁵ I or ¹⁰³ Pd is used. About 50 to 100 sealed brachytherapy sources are usually implanted in the cancer lesion part of the prostate and / or the peripheral part of the cancer lesion. Placed.

  By the way, the sealed braid source emits radiation, and it is necessary to store and store it in a container having the ability to shield radiation when not in use. As a container having the ability to shield radiation, a container using lead known as a radiation shielding material is generally used (see Patent Document 1 and Patent Document 2).

  Further, as an example using a material other than lead, a shielding material for a sealed small wire source using stainless steel is disclosed (Non-patent Documents 2 and 3).

Special table 2008-540042 gazette JP 2004-151117 A

Nippon Mediphysics Co., Ltd. “Breast Source Therapy for Prostate Cancer” [searched on February 16, 2011], Internet <URL: http: // www. nmp. co. jp / seed / about / brachytherapy. html> "ONCURA RAPID Strand ™ TM Instructions for the use of Rapid Strand for Intertension Brachytherapy Treatments", [online], p. 6, [Search on April 13, 2011], Internet <URL: http: // www. oncura. net / media / pdf / RAPID-SPC. pdf> Medicon Inc., Seed Applicator Attachment, [online], [April 13, 2011 Search], Internet <http: // www. info. pmda. go. jp / downfiles / md / PDF / 780045_27B1X00052000103_B_04_04. pdf>

  However, although lead has an excellent radiation shielding effect, when it is discarded, there is a problem that the environment is contaminated with lead (lead damage problem). When tungsten or stainless steel is used, environmental problems due to lead as described above can be avoided. However, these materials generally require machining, which increases processing costs and reduces the processing costs even when mass-produced. Therefore, there is a disadvantage that the increase in cost as a whole is inevitable. Tungsten also has a drawback that the material itself is expensive.

In such a situation, the problem to be solved by the present invention is a container containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source, and leakage of radiation to the outside of the container It is an object of the present invention to provide a hermetically sealed brachytherapy container that can prevent the environmental pollution caused by lead and can reduce or eliminate the problem of environmental pollution caused by lead and that is excellent in workability during manufacture.

That is, the present invention is a container that houses a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source, and the entire surface of the container is made of a radiation shielding material. It relates to a sealed brachytherapy container that is at least partially zinc and / or zinc alloy.

  Conventionally, lead or tungsten is generally used as a material that shields radiation, and other materials cannot provide a sufficient shielding effect. Therefore, it is common knowledge that it is not used as a shielding material. Met. As materials other than lead and tungsten, an example using stainless steel is rarely disclosed. Contrary to such common technical knowledge, we can mold the brachywire source, especially the brachytherapy source that has fallen out of the body, and even zinc or zinc alloy with excellent processability is sufficient. It has been found that a shielding effect can be obtained and can be used as a shielding material, and the present invention has been completed.

According to the present invention, a container for containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source, preventing leakage of radiation to the outside of the container, and an environment caused by lead It is possible to provide a sealed brachytherapy container that can reduce or eliminate the contamination problem and has excellent characteristics of processability during production.

It is a figure which shows the example of the embodiment of the sealed braid source storage container of this invention. It is a figure which shows the sealed brachytherapy container of this invention used in Example 1. FIG. It is a figure which shows the surface dose rate in Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail.

The container of the present invention is a container for containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source.

  The brachytherapy is as described above, and a brachytherapy source that emits radiation is embedded in a cancer lesion portion and / or a peripheral portion of the cancer lesion, and the radiation emitted from the brachytherapy source is cancer. It is a treatment method that destroys cancer cells by irradiating the lesion area.

  Brachytherapy is widely used especially for the treatment of prostate cancer. Hereinafter, the present invention will be described by taking the treatment of prostate cancer as an example.

¹²⁵ I or ¹⁰³ Pd is used as a radiation source for emitting radiation, and characteristic X-rays and γ-rays emitted from these are used.

As a sealed brachytherapy source, ¹²⁵ I or ¹⁰³ Pd, which is a radiation source chemically bonded to a silver short wire, was sealed in a cylindrical titanium capsule having a length of several millimeters and a diameter of about 1 millimeter. Things are used. About 50-100 brachytherapy sources are usually implanted in the cancer lesion and / or the surrounding area of the prostate, and the implanted brachytherapy is once permanently retained in the body. It is burned. As will be described later, the sealed brachytherapy source embedded in the body may rarely fall off and be discharged into the body. In such a case, the sealed brachytherapy source is stored in a container that shields radiation from the dropped sealed brachytherapy source. There is a need to. In such a case, the sealed brachytherapy container according to the present invention can be used as a container for housing the sealed brachytherapy source that has dropped out.

  In the sealed brachytherapy container of the present invention, the entire surface of the container is made of a radiation shielding material, and at least a part of the shielding material is zinc or a zinc alloy. By adopting such a structure, leakage of radiation from the container can be prevented. The whole surface of the container means all surfaces including the upper and lower surfaces (ceiling surface and bottom surface) and side surfaces of the container.

  One of the greatest features of the present invention resides in that at least a part of the radiation shielding material is made of zinc and / or a zinc alloy. This can reduce or eliminate the problem of environmental pollution caused by lead generated when lead is used as the shielding material. From the viewpoint of completely solving the problem, it is preferable that all of the shielding material is made of zinc and / or a zinc alloy.

  As a zinc alloy, what contains 2-6 weight% of aluminum and 0.01-0.08 weight% of magnesium as metal components other than zinc can be used. By using a zinc alloy, the moldability at the time of manufacturing a container can be improved compared with the case where pure zinc is used.

  As described above, the sealed brachytherapy container of the present invention suppresses environmental pollution due to lead by using zinc and / or a zinc alloy, but is not based on the present invention and other than zinc and / or a zinc alloy. When the above metal is used, the following inconvenience occurs. In other words, when using iron, stainless steel, brass, copper, etc., it is necessary to make the shielding material thicker than zinc in order to sufficiently shield the radiation, and the volume and weight increase, and handling In addition, it is necessary to perform machining at the time of manufacturing the container, which increases the manufacturing cost. Moreover, when tungsten is used, a sintering process is required, which increases the manufacturing cost. Further, when tin is used, tin is expensive and inferior in radiation shielding ability. On the other hand, when the zinc and / or zinc alloy according to the present invention is used, casting can be performed, which is advantageous in terms of manufacturing cost.

  Next, a preferred embodiment of the sealed brachytherapy container of the present invention and a method for using the same will be described.

  It is preferable from the viewpoint of handling that the sealed brachytherapy container of the present invention is used in combination with an outer container made of plastic and an inner container made of plastic (FIG. 1). That is, the sealed brachytherapy source container of the present invention is placed in the outer container, the inner container is placed in the sealed braid source containing container, and the sealed braid source is housed in the inner container. The outer container and the inner container and the sealed brachytherapy container of the present invention may be relatively movable and may not be fixed. Each of the outer container and the inner container has a structure in which the body portion and the lid portion can be opened and closed in a screw form. The sealed brachytherapy container of the present invention is also composed of a barrel portion and a lid portion, but the barrel and the lid may be any structure as long as they are in close contact with each other, and may not be a screw type. At the time of use, the lid of the inner container is opened, a sealed brachytherapy source is inserted, and the lid of the inner container is closed with a screw. The inner container is placed in the barrel portion of the sealed brachytherapy container of the present invention and covered. The sealed brachytherapy container is placed on the barrel of the outer container, and the lid is closed with a screw. At this time, the upper surface of the lid of the sealed brachytherapy source container and the lower surface of the lid of the outer container are in contact with each other. It is crimped and sealed to the barrel of the source container.

  The size and shape of the sealed brachytherapy container according to the present invention need only be able to accommodate the sealed brachytherapy source. For example, the cylindrical braid having a diameter of 30 to 40 mm and a height of 30 to 40 mm or a diameter of 10 to 10 A long cylindrical shape having a length of about 20 mm and a length of about 50 to 150 mm can be given. The sealed brachytherapy container is composed of a body portion and a lid portion, and both can be in close contact with each other. Here, the structure may be any structure that can be in close contact, and need not be sealed with a screw structure or the like. The thickness of the shielding material is preferably 1 to 5 mm. If the thickness is too thin, the radiation shielding ability may be insufficient. On the other hand, if the thickness is too thick, it becomes heavy and inconvenient to handle, which is also disadvantageous in terms of material cost.

  The structure and size of the outer container and the inner container are not limited as long as they are suitable for the above usage. In addition, as a plastic, a polypropylene can be mention | raise | lifted, for example.

  The sealed brachytherapy container of the present invention is optimally used for the purpose of housing a sealed brachytherapy source for the treatment of prostate cancer. Here, the brachytherapy source for prostate cancer treatment may be the one before being inserted into the human body for the treatment of prostate cancer. By the way, the brachytherapy source for treating prostate cancer is implanted in the cancer lesion part of the prostate and / or the peripheral part of the cancer lesion. Although retained, the brachytherapy source implanted in the body may be excreted out of the human body along with urine, and this excreted brachytherapy source may be referred to as a “decline”. The declining line source is collected and returned to the medical facility where the procedure was performed. The sealed brachytherapy container of the present invention is also optimally used as a temporary storage container for a dropout source when returning the dropout source to a medical facility.

  There is no restriction | limiting in the method of manufacturing the sealed braid source container of this invention, The normal casting processing method which processes zinc or a zinc alloy can be applied.

  Next, an example explains the present invention.

Example 1, Reference Example 1
As the sealed braid source container, the one shown in FIG. 2 was used. That is, it is made of a zinc alloy (aluminum 3.5 to 4.3 wt%, magnesium 0.02 to 0.06 wt%, remaining zinc) having a thickness of 4 mm on the upper and lower surfaces of the container and a thickness of 2 mm on the side surface. It has a cylindrical shape with a height of 36 mm and a height of 32 mm, and the lid portion is formed in the barrel portion and the seal stamp. As the sealed wire source, a cylindrical titanium capsule having a length of 4.6 mm and a diameter of 0.8 mm sealed with ¹²⁵ I chemically bonded to a silver short wire was used. 5 sealed small wire sources of 10 MBq each are placed in a plastic inner container (made of polypropylene, thickness 1 mm, diameter 30 mm, height 20 mm cylindrical with an upper lid), and the inner container is accommodated in the sealed small beam source. It was put in a container and further housed in a plastic outer container (made of polypropylene, thickness 1 mm, diameter 40 mm, height 36 mm with an upper lid), and used for measurement of leakage radiation dose. The measurement point was performed at a point that was in close contact with each of the top surface, the side surface, and the bottom surface of the sealed brachytherapy container, and a point that was 1 m away. The radiation dose was measured with an ionization chamber measuring instrument (451B-DE-S1 manufactured by INOVISION).
Moreover, it carried out similarly to Example 1 except having used the container whose shielding material is lead as the reference example 1. FIG.
The measurement results are shown in Table 1. As is apparent from this table, no leakage radiation was detected at all measurement points in both Example 1 and Reference Example 1. From this result, it can be seen that the sealed brachytherapy container using the zinc alloy as a shielding material according to the present invention has the same leakage radiation shielding effect as the sealed brachytherapy container containing lead as a shielding material.

・表中の数値は各地点の測定値からバックグラウンド値を引いた値（単位 μＳｖ／ｈ）である。
・密封小線源収容容器の上蓋を開放した場合の容器上部表面（密着）での測定値は３２０μＳｖ／ｈであった。

・ The numerical values in the table are values (unit μSv / h) obtained by subtracting the background value from the measured values at each point.
-The measured value on the upper surface (close contact) of the container when the upper lid of the sealed brachytherapy container was opened was 320 μSv / h.

Example 2
Based on the measurement result when the radiation source was ¹²⁵ I, the container surface dose rate when the radiation source was ¹⁰³ Pd was obtained by simulation. The calculation code used for the simulation is an electron / photon Monte Carlo simulation code EGS5 (H. Hirayama, Y. Namito, A. F. Bielajew, SJ. R. Nelson: The EGS5 Code System, SLAC-R-730 and KEK Report 2005-8: 2005).
The result of the simulation is shown in FIG. From FIG. 3, the sealed brachytherapy container of the present invention using a zinc alloy as a shielding material has a sufficient leakage radiation shielding effect when the radiation source is ¹⁰³ Pd as well as when the radiation source is ¹²⁵ I. You can see that

The present invention is a container for containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source, preventing leakage of radiation to the outside of the container, and an environment caused by lead It is possible to provide a sealed brachytherapy container that can reduce or eliminate the contamination problem and has excellent characteristics of processability during production.

1 Sealed beam source 2 Inner container (body) (plastic)
3 Inner container (lid) (plastic)
4 Sealed small beam source container (body) (zinc alloy)
5 Sealed beam source container (lid) (zinc alloy)
6 Outer container (body) (plastic)
7 Outer container (lid) (plastic)

Claims (5)

A container containing a brachytherapy source for brachytherapy using ¹²⁵ I or ¹⁰³ Pd as a radiation source,
An inner container that houses the sealed braid source;
A sealed brachytherapy container containing a first trunk having a first opening and a first lid covering the first opening, and housing the inner container in the first trunk;
An outer container that includes a second body having a second opening and a lid that covers the second opening, and that accommodates the sealed brachytherapy source container in the second body;
Have
The entire surface of the sealed brachytherapy container is made of a radiation shielding material, and at least a part of the shielding material is zinc and / or a zinc alloy,
The second opening is covered with the second lid part by closely contacting the second lid part and the second body part in a screw form,
When the first lid covers the first opening and the second lid covers the second opening, the upper surface of the first lid and the lower surface of the second lid A container having a structure in contact with. The container according to claim 1, wherein all of the shielding material is zinc and / or a zinc alloy. The container according to claim 1 or 2, wherein the brachytherapy source is for treating prostate cancer. The container according to claim 3, wherein the brachytherapy source is before being inserted into a human body for the treatment of prostate cancer. The container according to claim 3, wherein the sealed brachytherapy source is dropped from the human body after being inserted into the human body for the treatment of prostate cancer.

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