JPH0723949A - Manufacture of ultrasonic coupler - Google Patents

Abstract

PURPOSE:To provide a manufacturing method of an ultrasonic coupler which prevents mixing of air bubbles, and which is sterilized. CONSTITUTION:After water solution 42 is injected into a die 30, the die 30 is cooled to 20 deg.C, it is frozen for 24 hours at this temperature, and then it is thawed, so primarily crosslinked PVA gel 44 is obtained as illustrated in a figure (c). Next, the PVA gel 44 is taken out of a lower die 34 to be contained in a container 46 as illustrated in a figure (d). It is then transported to a gamma ray radiation device, where a gamma ray of 2.5Mrad is radiated to the PVA gel 44 to be secondarily crosslinked and sterilized. An ultrasonic coupler of a specified form on which a joint member 40 is installed can thus be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ultrasonic coupler arranged between an ultrasonic probe and an object to be observed when using an ultrasonic diagnostic apparatus.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus for displaying a tomographic image of a human body using ultrasonic waves is widely used. With this ultrasonic diagnostic device, the thyroid gland, carotid artery, which exists near the body surface,
A case of observing a diagnosis site such as a mammary gland will be described with reference to the drawings. FIG. 3 is a schematic diagram showing a state in which an ultrasonic probe for transmitting and receiving ultrasonic waves is in direct contact with the body surface, and FIG. 4 is an ultrasonic good conductor between the ultrasonic probe and the body surface. It is a schematic diagram which shows the state which has arrange | positioned the acoustic wave coupler.

As shown in FIG. 3, the ultrasonic probe 10 is used.
When the body is brought into direct contact with the body surface 12, the ultrasonic beam 1
Since the converging position of 4 is the position 16 away from the body surface 12, the resolution is lowered when observing the diagnostic region 18 existing near the body surface 12. In order to improve the resolution when observing the diagnostic region 18 existing near the body surface 12, as shown in FIG. 4, an ultrasonic coupler is provided between the ultrasonic probe 10 and the body surface 12. 20 is arranged so that the ultrasonic beam 14 may be converged in the vicinity of the diagnosis region 18.

This ultrasonic coupler has excellent biocompatibility,
It is desired to have flexibility, physical strength, and good ultrasonic transmission. For this reason, the ultrasonic coupler is a non-hydrogel material made of urethane rubber or silicone rubber, polyvinyl alcohol (hereinafter referred to as PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (P).
It is made of a high molecular weight hydrogel material such as EO), and is subjected to sterilization treatment to improve safety and thus can be used intraoperatively.

Conventionally, the following methods have been known as a method for manufacturing a sterilized ultrasonic coupler. (1) An ultrasonic coupler is produced by irradiating an aqueous solution containing PVA with a concentration of several to several tens% with radiation such as gamma rays to cause sterilization and gelation (JP-A-63-
292945). (2) An aqueous solution containing PVA at a concentration of several to several tens% is irradiated with radiation such as gamma rays to be sterilized, and then frozen and thawed to gel. (JP-A-2-86
No. 838)

[0006]

However, in the manufacturing methods (1) and (2) described above, bubbles may be mixed into the aqueous solution containing PVA due to vibration during transportation to the gamma ray irradiation device. . When gelled by irradiating an aqueous solution containing bubbles with gamma rays,
An ultrasonic coupler containing bubbles is manufactured. When observing a diagnostic region with ultrasonic waves using this ultrasonic coupler mixed with air bubbles, the ultrasonic waves are reflected by the air bubbles, which may affect the image representing the observation target, and accurate diagnosis may not be possible. There is a problem.

In view of the above circumstances, it is an object of the present invention to provide a method for manufacturing an ultrasonic coupler which prevents the inclusion of bubbles.

[0008]

In order to achieve the above-mentioned object, a method of manufacturing an ultrasonic coupler according to the present invention comprises subjecting an aqueous solution containing a polymer to a thermal cycle of freezing and thawing to primary crosslink the aqueous solution. Then, the primary crosslinked aqueous solution is subjected to secondary crosslinking by irradiating the primary crosslinked aqueous solution with radiation.

Here, the primary crosslinked aqueous solution may be sealed in a container having a predetermined shape, and the aqueous solution may be irradiated with radiation. In addition, in a container for sealing the primary cross-linked aqueous solution, 1
It is preferable to store a preservative solution for preserving the sub-crosslinked aqueous solution. Further, this container is preferably a polystyrene container.

Furthermore, it is preferable that the aqueous solution contains polyvinyl alcohol. Furthermore, it is preferable that the radiation is gamma rays.

[0011]

According to the method for producing an ultrasonic coupler of the present invention, after the aqueous solution undergoes primary cross-linking by applying a thermal cycle,
This primary crosslinked aqueous solution is irradiated with radiation. For this reason, it is in a gel state before being transported to the radiation irradiator, and bubbles are not mixed therein. Therefore, by irradiating the primary cross-linked aqueous solution with radiation, secondary cross-linking can be performed, whereby a sterilized ultrasonic coupler can be manufactured without inclusion of bubbles.

Here, when the primary crosslinked aqueous solution is sealed in a container having a predetermined shape and irradiated with radiation, an ultrasonic coupler having a shape corresponding to the shape of the container can be manufactured. Also,
When the storage solution for storing the primary crosslinked aqueous solution is contained in the container for sealing the primary crosslinked aqueous solution, the stability of the gel during transportation is good. Further, when the polystyrene container is stable against radiation, the life of the container is extended.

[0013]

Embodiments of the method of manufacturing an ultrasonic coupler according to the present invention will be described below with reference to the drawings. FIG. 1 shows the first of the present invention.
It is sectional drawing which shows the ultrasonic coupler manufacturing method of an Example, and the ultrasonic coupler manufacturing mold used by this method. The ultrasonic coupler manufacturing die 30 is composed of an upper die 32 made of metal and a lower die 34 made of silicone rubber. An injection port 36 for injecting an aqueous solution containing PVA is formed in the upper mold 32. At the center of the upper mold 32, a convex portion 38
However, it is formed with the surface 38a forming the joint surface between the ultrasonic probe (not shown) and the ultrasonic coupler facing downward.
Further, a joining member 40 for joining the ultrasonic probe and the ultrasonic coupler is attached to the convex portion 38.

In manufacturing the ultrasonic coupler, first, 50 g of polyvinyl alcohol was added to 950 ml of pure water, and this was placed in a vacuum stirrer having a pressure of 60 cmHg and dissolved while stirring at a temperature of 86 to 90 ° C. , An aqueous solution containing PVA by cooling to room temperature 4
Get 2. This aqueous solution 42 is injected into the mold 30 through the injection port 36 as shown in FIG. The aqueous solution 42 need only be injected until it covers the bonding surface 38a, and does not need to be injected until the entire interior of the mold 30 is filled. After injecting the aqueous solution 42 into the mold 30, the mold 30 is -20
By cooling to 0 ° C., freezing at this temperature for 24 hours, and then thawing, the primary crosslinked PVA gel 44 is obtained as shown in FIG. 1 (c). The hardness of this PVA gel 44 is 7 × 10 ³ dyne / cm ² . Then PVA
As shown in FIG. 1D, the gel 44 is taken out from the lower mold 34 together with the upper mold 32 and the joining member 42. After taking out, the joining member 40 and the PVA gel 44 are housed in a container 46 as shown in FIG. The container 46 is made of polystyrene and is therefore relatively stable to gamma rays. Next, as shown in FIG.
Preservation liquid 48 containing pure water in such an amount that the VA gel 44 is sufficiently immersed
Then, it is placed in a container 46 and sealed by thermocompression bonding with an aluminum foil lid 50. Here, the storage solution 48 does not have to be put in the container 46, but the stability of the PVA gel 44 is better when it is put.

PVA gel 4 in the state shown in FIG. 1 (f)
4 is conveyed to a gamma ray irradiator, and the PVA gel 44 is irradiated with 2.5 Mrad gamma ray for secondary crosslinking and sterilization. Thereby, the ultrasonic coupler having the predetermined shape to which the joining member 40 is attached is manufactured. Regarding the ultrasonic coupler manufactured as described above, the water content, the gel hardness, and the acoustic characteristics (sound velocity, impedance,
The decay rate) was investigated. The results are shown in Table 1.

[0016]

[Table 1]

Here, the water content is defined as follows. Moisture content = {(weight of water-containing polymer−absolute weight of polymer) / weight of water-containing polymer} × 100% The gel hardness was measured using a card meter (ME-303, manufactured by Iio Electric Co., Ltd.).

Table 2 shows P with changes in gamma ray irradiation amount.
The change of the hardness of VA gel is shown.

[0019]

[Table 2]

As shown in Table 2, as the gamma ray irradiation amount increases, gelation progresses and becomes harder. The hardness due to this gamma ray irradiation is predicted in advance, and in the step of giving the first thermal cycle, the gelation is softened by controlling the freezing temperature, the freezing time and the freezing frequency. The preferred hardness is 1 × 10 ⁴ dyn
The hardness is e / cm ² or less. After that, the softly gelled product is irradiated with gamma rays to finish into a gel having a desired hardness.

Next, a second embodiment of the method of manufacturing the ultrasonic coupler of the present invention will be described with reference to FIG. In the manufacturing method of the second embodiment, first, as shown in FIG. 2A, the aqueous solution 42 (see FIG. 1B) is placed in a rectangular parallelepiped storage case 60.
Pour into. Next, as shown in FIG. 2 (b), a lid is covered with a rubber mold 62, and a freezing and a thawing are performed to give a heat cycle to perform primary crosslinking and gelation. After that, Figure 2
As shown in (c), the mold 62 is removed and the lid 64 is closed. The PVA gel 44 in the state shown in FIG. 2C is conveyed to a gamma ray irradiation device, and the PVA gel 44 is irradiated with gamma rays for secondary crosslinking and sterilization. As a result, as shown in FIG. 2D, the storage case 60
An ultrasonic coupler corresponding to the above shape is manufactured. Further, since it can be stored in the state shown in FIG. 2C until it is used, the aseptic state can be maintained.

[0022]

As described above, according to the method for manufacturing an ultrasonic coupler of the present invention, bubbles are generated because secondary cross-linking is performed by irradiating radiation after primary cross-linking by applying a thermal cycle. An ultrasonic coupler that is not mixed can be manufactured. Further, since the sterilizing effect by irradiation of radiation and gelation are performed at the same time, the number of working steps is small and the quality is constant.

[Brief description of drawings]

FIG. 1 is a sectional view showing an ultrasonic coupler manufacturing method according to a first embodiment of the present invention and an ultrasonic coupler manufacturing die used in this method.

FIG. 2 is a sectional view showing an ultrasonic coupler manufacturing method according to a second embodiment of the present invention and an ultrasonic coupler manufacturing die used in this method.

FIG. 3 is a schematic view showing a state where an ultrasonic probe is brought into direct contact with the body surface.

FIG. 4 is a schematic diagram showing a state in which an ultrasonic coupler is arranged between the ultrasonic probe and the body surface.

[Explanation of symbols]

 30 Ultrasonic coupler manufacturing mold 32, 62 Upper mold 34 Lower mold 36 Injection port 38 Convex portion 40 Joining member 42 Aqueous solution containing PVA 44 PVA gel 46 Container 48 Preservation liquid 50, 64 Lid 60 Storage case

Claims (6)

[Claims] 1. An aqueous solution containing a polymer is first crosslinked by subjecting the aqueous solution to a thermal cycle of freezing and thawing, and the aqueous solution that is primary crosslinked is irradiated with radiation to cause the aqueous solution to be primary crosslinked. A method for producing an ultrasonic coupler, characterized in that the secondary cross-linking is performed. 2. An aqueous solution containing a polymer is subjected to a thermal cycle of freezing and thawing to primary crosslink the aqueous solution, and the primary crosslinked aqueous solution is sealed in a container having a predetermined shape, and then sealed in the container. A method for producing an ultrasonic coupler, characterized in that the aqueous solution obtained by primary crosslinking is subjected to secondary crosslinking by irradiating the aqueous solution thus obtained with radiation. 3. The method of manufacturing an ultrasonic coupler according to claim 2, wherein the container contains a preservative solution for preserving the primary crosslinked aqueous solution. 4. The method for manufacturing an ultrasonic coupler according to claim 2, wherein the container is a polystyrene container. 5. The method for producing an ultrasonic coupler according to claim 1, wherein the aqueous solution contains polyvinyl alcohol. 6. The method for manufacturing an ultrasonic coupler according to claim 1, wherein the radiation is gamma rays.