JP2003310610A - Ultrasonic phantom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a numerical value similar to human soft tissue in both a sound velocity and a damping factor, and to maintain acoustic characteristics over a long period, in an ultrasonic phantom using a polyurethane resin as a base material. <P>SOLUTION: In this phantom, the base material consists mainly of a reactive resin comprising a polybutadiene polyol and a diphenylmethane diisocyanate, and a nonreactive diluent selected from aliphatic compounds or aromatic compounds. Organic powder fillers are uniformly dispersed in the base material. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultrasonic phantom using urethane resin as a base material, and is used in the fields of calibration and evaluation of ultrasonic diagnostic equipment and probes, and other training of doctors and engineers.

[0002]

2. Description of the Related Art As a urethane resin phantom of this type, the one disclosed in Japanese Patent Laid-Open No. 11-262487 is known. In this known phantom, the gel-like base material that has been used conventionally, such as agar or gelatin, changes the acoustic characteristics of the base material due to the evaporation of water, and the rubber-based base material provides an appropriate sound velocity value. It was developed in order to satisfy these requirements because it was not used.

The base material of this known phantom is made of urethane water-swelling resin. The sound velocity of the soft tissue of the human body is said to be 1530 to 1540 (m / s), but in this known phantom, the sound velocity value of 1520 (m / s) approximated to this value.
) Is obtained, but the attenuation rate is 0.5 to 1.3 (db /
Since it is 0.39 (db / cm / MHz) for cm / MHz), there is a discrepancy with the acoustic characteristics of the human body, and as a result there is the inconvenience that only a standard value can be obtained. Since the material is water-swellable, its molding is complicated and requires a lot of man-hours. In addition, the water evaporates when exposed to the air, so it is necessary to replenish the water each time. , It was also inconvenient to store it.

[0004]

Technical Problem The present invention aims at obtaining an ultrasonic phantom using a urethane resin as a base material, in which both the sound velocity and the attenuation rate are approximate to the soft tissue of the human body and the acoustic characteristics can be maintained for a long period of time. This is an issue.

[0005]

[Technical Means] The first technical means for solving this technical means is (a) a reaction system resin composed of polybutadiene polyol and diphenylmethane diisocyanate, and a non-selected resin selected from aliphatic series and aromatic series. That is, the reaction system diluent was the main component of the base material, and (b) the organic powder filler was uniformly dispersed in the base material. The second technical means is to approximate the specific gravity of the organic powder filler and the specific gravity of the base material.

The phantom is required to have a sound velocity in the base material close to that of the human body. In the first technical means, a phantom base material is obtained by reacting a curing agent, diphenylmethane diisocyanate, with a main component polybutadiene polyol diluted with a non-reactive diluent selected from aliphatic and aromatic systems. Since it is made of urethane resin as a main component, a sound velocity value of about 1490 to 1520 (m / s) can be obtained. Since organic powder filler is added to this base material and dispersed uniformly, when ultrasonic measurement is performed using a phantom, the reflection / scattering due to ultrasonic waves becomes uniform and the penetrating force The scattering pattern can be made closer to that of a human, and the acoustic characteristics at different parts of the same base material will not vary.

As will be described later, as the amount of the reaction system resin is increased, and as the amount of the organic powder filler added is increased, the sound speed attenuation rate is increased. As the organic powder filler, powders of polypropylene, polyethylene, ethylene / vinyl acetate / vinyl alcohol copolymer and the like can be preferably used. Further, in order to uniformly disperse the organic powder filler, it is desirable to design the size and the addition amount of the powder in consideration of the viscosity of the base material.

In the second technical means, the specific gravity of the organic powder filler and the specific gravity of the base material are approximated. Therefore, if the organic powder filler is added and dispersed before curing of the base material,
The resin can be cured without settling. Incidentally, the specific gravity of each of the fillers listed above is close to that of the base material.

Sample 1 in which a non-reactive diluent was combined with a reactive resin composed of a base polybutadiene polyol and a curing agent diphenylmethane diisocyanate.
8 were prepared and the sound velocity and attenuation rate of each sample were measured. Table-
1 shows the result. (Table-1)

These samples use an aliphatic non-reactive diluent as the main agent and an aromatic non-reactive diluent as the curing agent. The sound velocity was measured without adding the organic powder filler. The sound velocity value is 1507 to 1521 (m / s), and the lowest sound velocity value differs from the average sound velocity value of the human body by 23 to 33 (m / s). Recognized to be in range. For these samples,
When the same test was performed by changing the frequency, the attenuation rate did not change significantly.

From Table 1, it can be understood that the attenuation rate (dB / cm / MHz) tends to increase as the amount of the reaction system resin increases. As will be described later, since the attenuation rate increases with the addition of the organic powder filler, the attenuation rate of the sound velocity in the state where the organic powder filler is not added is used as a rough guide. In the case of the samples shown in Table-1, organic powder filler was added to the base materials of Samples 3 to 8 and finally the average attenuation rate of the human body was 0.5 to 1.3 (dB / cm / MHz). ) Will be supported.

Table 2 and FIG. 1 show an ethylene / vinyl acetate / vinyl alcohol copolymer (200 mesh pass) added as an organic powder filler to Sample 5 in Table-1.
5 is a table and a graph showing changes in the attenuation rate when the addition amount of is changed. (Table-2)

In the graph, the X axis is the amount added (% by weight) and the Y axis is the attenuation rate (dB / cm / MHz). In the case of the samples shown in Table 1, the attenuation rate is approximately Y = It is changing by the linear expression of 0.4338X + 0.4447 (however, it depends on the regression analysis method).
From this, it can be read that the attenuation rate increases in proportion to the increase in the addition amount of the organic powder filler. In the case of the samples shown in this table and graph, the attenuation rate of the human body described above
The addition amount corresponding to 0.5 to 1.3 (dB / cm / MHz) is about 0.
By setting the range of 13 to 1.97% by weight, it is possible to obtain a phantom that approximates the acoustic characteristics of the human body.
Although the same test was performed for other organic powder fillers, the same tendency was observed in the change of the attenuation factor.

Table 3 shows the same amount (0.61% by weight) of the organic powder filler made of polypropylene, polyethylene and ethylene / vinyl acetate / vinyl alcohol copolymer having different particle diameters as compared with Sample 5 of Table-1. It shows changes in sound velocity and attenuation rate of each sample when added. (Table-3)

Sample 5-4 in Table-2 and sample 5-in Table-3
d is the same sample. It is recognized that when the particle size of the organic powder filler is large, the sound velocity is slightly decreased and the attenuation rate is increased. If the particle size is 50 mesh, the attenuation rate will be significantly increased, so it is desirable to add a filler of 75 mesh or more.

[0016]

As described above, in the phantom according to the present invention, it is possible to obtain numerical values that are close to the soft tissue of the human body in both the speed of sound and the attenuation rate. Further, unlike a known phantom or gel-like so-called hydro-type one, since the phantom is not impregnated with water, the acoustic characteristics do not change due to evaporation of water. Also,
By adjusting the amount of the reaction resin of the urethane resin and the addition amount of the organic powder filler, it is possible to change the sound velocity and the attenuation rate. Therefore, by changing these addition amounts, the characteristics of the soft tissue of the human body can be changed. There is also an advantage that a phantom tailored to the above can be manufactured, and a human-shaped phantom in which organs such as muscles, organs, and brain are arranged can be manufactured.

[Brief description of drawings]

FIG. 1 is a graph showing changes in the amount of filler added and the attenuation rate.

Claims (2)

[Claims] 1. An ultrasonic phantom having a urethane resin as a base material, which comprises a base material containing a reactive resin composed of polybutadiene polyol and diphenylmethane diisocyanate and a non-reactive diluent selected from an aliphatic type or an aromatic type. An ultrasonic phantom that contains the organic powder filler as the main component and that is uniformly dispersed in the base material. 2. The ultrasonic phantom according to claim 1, wherein the specific gravity of the organic powder filler and the specific gravity of the base material are approximated to each other.