CN110811683A - Tissue-imitated phantom for omnidirectional slice thickness detection of ultrasonic tomography equipment - Google Patents

Abstract

The invention discloses a tissue phantom for detecting the omnidirectional slice thickness of an ultrasonic tomography device, which is in a round table shape and comprises: a phantom housing, an acoustic window (3), a background tissue-mimicking material (9) and a target; the phantom shell is formed by fixing an upper panel (2), a lower panel (6) and a round table target seat (8) between the upper panel and the lower panel, the phantom shell and an acoustic window (3) stuck to the side surface of the round table form a closed space together, a background imitation tissue material (9) is filled in the closed space, and the target is a diffuse scattering layer (7) which is clung to and covers the side surface of the round table target seat (8); an inlet filled with a background tissue-imitating material (9) is arranged on the upper panel (2), and a plugging rubber is stuck on the inlet. The tissue-imitated body model can be used for detecting and evaluating the thickness of the omnidirectional slice of the ultrasonic tomography equipment.

Description

Tissue-imitated phantom for omnidirectional slice thickness detection of ultrasonic tomography equipment

Technical Field

The invention belongs to the field of quality detection of medical instruments, and particularly relates to a tissue-imitated body model for omnidirectional slice thickness detection of an ultrasonic tomography device.

Background

B-ultrasonic and X-CT, magnetic resonance imaging, nuclear medicine imaging are the four most practical diagnostic imaging techniques in the present day, and B-ultrasonic is the top of the four in terms of popularity. Particularly under specific conditions in China, the B-mode ultrasound technology is not only used for routine diagnosis of various diseases, but also is generally used in the fields of birth control, eugenics and reproductive health. The performance and quality of the Chinese characters are related to economic benefits of manufacturers and hospitals, and the health and the welfare of the whole Chinese nation including offspring and offspring are affected. In view of this, the national authorities have established and released the corresponding technical standards as legal compliance for their life-long quality supervision.

In clinic, doctors make diagnosis according to the information provided by the ultrasonic scanning sonogram, so the image quality is considered as the primary factor for measuring the quality of the B-ultrasonic product and judging whether the B-ultrasonic works normally or not. According to international consensus, the technical indicators (i.e. performance) characterizing the image quality include dead zone, depth of detection, axial (longitudinal) resolution, lateral (transverse) resolution, pitch resolution, contrast resolution, and geometric errors of display and measurement, etc. The material technical means which can make objective, rapid, vivid and quantitative evaluation on the performance and quality of the B ultrasonic equipment in all links of development, production, sale, use, maintenance and legal management (quality supervision and inspection, metrological verification, import and export commodity inspection) of the B ultrasonic equipment only has an imitated tissue ultrasonic phantom. An ultrasonic Tissue simulation Phantom is translated from English Tissue simulation ultrasonic Phantom, namely a human physical model simulating soft Tissue in the aspect of ultrasonic propagation characteristics, and is a passive testing device which is composed of an ultrasonic Tissue simulation material (TM material for short), a plurality of testing targets embedded in the material, an acoustic window, a shell, an indicating decoration panel and the like. The tissue-imitated ultrasonic body model is specified equipment for executing national technical standards and metrological verification procedures, and has the characteristics of a standard device.

With the development of electronic technology and biomedical engineering, more and more medical ultrasonic-based diagnosis and treatment methods and equipment appear. Such as ultrasonic computed tomography (USCT), which is a promising technique for early breast tumor detection and diagnosis. The technology scans and images the mammary gland in a water tank through a ring array ultrasonic transducer, and the imaging modes comprise a B ultrasonic mode using ultrasonic reflected wave signals, an acoustic velocity measurement imaging mode using transmitted wave signals and an acoustic attenuation mode. The ultrasonic scanning tomography can be realized in various ways, such as forming a series of tomography images through longitudinal mechanical scanning of an annular array, forming tomography images after mechanical scanning of a plurality of pairs of transducers and spatial sampling, or performing electronic scanning tomography by using a spatial semi-ellipsoidal array transducer. The ultrasonic tomography device generally uses deaerated water as a coupling medium between a transducer and a human body, is mainly used for three-dimensional ultrasonic scanning imaging of breasts, and can also be used for tomography imaging of limbs and other parts.

All of the meters used for quality testing are periodically certified or calibrated as required by the medical instrument manufacturing industry and professional quality testing agencies quality systems. The tissue-imitated ultrasonic phantom belongs to a tissue substitute and is not a measuring instrument, a standard device in the sense of metrology does not exist, and the metrological verification or calibration cannot be implemented, but a rule of regular detection and comparison is formed from the end of the last century because the quality of ultrasonic diagnostic equipment is directly influenced, and the rule is accepted and followed by related fields. As an ultrasonic tomography imaging device of a medical instrument, a tissue-imitated phantom is supposed to be used for imaging performance and quality inspection. At present, aiming at the new ultrasonic imaging diagnostic equipment of USCT, the current tissue-imitating body model is no longer suitable for detecting the performance of the USCT.

Disclosure of Invention

The invention aims to overcome the technical defects and provides a tissue-imitated body model for detecting the ultrasonic tomography imaging equipment, which can be specially used for inspecting and detecting the thickness of an omnidirectional slice of the ultrasonic tomography imaging equipment and is an ultrasonic passive device.

In order to achieve the above object, the present invention provides a tissue phantom for omnidirectional slice thickness detection of an ultrasonic tomography apparatus, wherein the tissue phantom is in a circular truncated cone shape, and comprises: a phantom housing, an acoustic window, a background tissue-mimicking material, and a target; the phantom shell is formed by fixing an upper panel, a lower panel and a round table target seat between the upper panel and the lower panel, the phantom shell and an acoustic window stuck on the side surface of the round table form a closed space together, background imitation tissue materials are filled in the closed space, and the target is a diffuse scattering layer which is clung to and covers the side surface of the round table target seat; an inlet filled with a background tissue-imitating material is arranged on the upper panel, and a plugging rubber is attached to the upper panel.

As an improvement of the device, the material of the phantom housing is hard structural plastic.

As an improvement of the device, the sound window adopts a polyester film with the thickness of 50-100 mu m.

As an improvement of the device, the acoustic window is connected with the upper panel and the lower panel, and the included angle between the section of the acoustic window and the lower panel ranges from 60 degrees to 90 degrees.

As an improvement of the device, the background tissue-imitating material is a water-based polymer gel matrix composite.

As an improvement of the device, the included angle between the tangent plane of the side surface of the circular truncated cone target holder and the lower panel ranges from 10 degrees to 80 degrees.

As an improvement of the above device, the diffuse scattering layer is formed by coating a layer of substrate with granular acoustic diffuse scattering material, and the thickness of the diffuse scattering layer is less than 1 mm.

As an improvement of the device, the inlet of the upper panel is a round hole arranged near the circumference and is blocked by a blocking rubber, and the blocking rubber is made of a vacuum rubber.

As an improvement of the device, the background tissue-imitating material can be maintained by using special maintenance liquid, and the maintenance liquid is injected through the plugging rubber.

The invention has the advantages that:

1. compared with the prior similar products, the tissue-imitated body model designed and manufactured according to the invention is specially used for the omnidirectional slice thickness detection and the pitching acoustic beam imaging performance evaluation of the ultrasonic tomography equipment; the slice thickness of all array element imaging on 360 degrees of the annular array transducer can be measured by single measurement imaging, and the difference of the parameters between the array elements is measured, quantized and compared, so that the circumferential uniformity of the annular array on the slice thickness parameter layer is obtained;

2. by the design of the inclined plane sound window, the invention avoids the false image caused by multiple reflections between the transducer and the sound window;

3. the tissue-imitating body model has original maintainability, and the service life of the body model can be greatly prolonged by regular maintenance and injection maintenance.

Drawings

FIG. 1 is a side external view of a phantom of tissue of the present invention for omnidirectional slice thickness detection in an ultrasonic tomography device;

FIG. 2 is a perspective view of the inside of an anechoic window of a phantom of tissue phantom for omnidirectional slice thickness detection of an ultrasonic tomography device according to the present invention;

FIG. 3 is a side cutaway view of a phantom of the invention for omnidirectional slice thickness detection in an ultrasonic tomography device;

FIG. 4 is a central sectional view of a phantom of the invention used for omnidirectional slice thickness detection in an ultrasonic tomography device;

figure 5 is a schematic diagram of a tissue phantom simulating embodiment of the invention for omnidirectional slice thickness detection of an ultrasonic tomography device.

Reference numerals:

1. tissue phantom 2, upper panel 3 and acoustic window

4. Plugging rubber 5, round hole 6 and lower panel

7. Diffuse scattering layer 8, round table target seat 9 and background tissue imitation material

10. Annular array transducer

Detailed Description

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

All of the meters used for quality testing are periodically certified or calibrated as required by the medical instrument manufacturing industry and professional quality testing agencies quality systems. The ultrasonic tissue-imitating body model belongs to a tissue substitute, and has formed a rule of regular detection and comparison from the end of the last century because the ultrasonic tissue-imitating body model directly influences the judgment on whether the quality of ultrasonic diagnostic equipment is qualified or not, and is recognized and followed by various related fields. The product corresponding to the invention is used for quality detection and evaluation of the ultrasonic tomography equipment and circumferential slice thickness detection and measurement of the ultrasonic imaging equipment.

The tissue-imitated body model is specially used for an ultrasonic passive device for evaluating the thickness detection quantity and the imaging performance of an acoustic beam slice of ultrasonic tomography imaging equipment. Ultrasonic computed tomography (USCT) generally uses a ring array ultrasonic transducer to scan and image a human body (such as breast) in a water tank, and the imaging modes include a B-mode using ultrasonic reflected wave signals, a sound velocity measurement imaging mode using transmitted wave signals, and an acoustic attenuation mode. The ultrasonic scanning tomography can be realized in various ways, such as forming a series of tomography images through longitudinal mechanical scanning of an annular array, forming tomography images after mechanical scanning of a plurality of pairs of transducers and spatial sampling, or performing electronic scanning tomography by using a spatial semi-ellipsoidal array transducer. The ultrasonic tomography device generally uses deaerated water as a coupling medium between a transducer and a human body, is mainly used for three-dimensional ultrasonic scanning imaging of breasts, and can also be used for tomography imaging of limbs and other parts.

As shown in fig. 1 and fig. 2, the Tissue-Mimicking phantom 1 is in a circular truncated cone shape, and mainly comprises a phantom housing, an acoustic window 3, a target and a background Tissue-Mimicking Material (TMM) 9. The phantom shell is formed by fixing an upper panel 2, a lower panel 6 and a circular truncated cone target stand 8, and is made of hard structural plastic; preferably, the rigid structural plastic is organic glass (PMMA, chemical name is polymethyl methacrylate) material, and may be other structural plastics, such as ABS acrylonitrile-butadiene-styrene terpolymer, polyvinyl chloride plastic, and the like. The upper panel 2 and the lower panel 6 form the upper surface and the lower surface of the circular truncated cone-shaped appearance, and the circular truncated cone target stand 8 is arranged between the upper panel 2 and the lower panel 6. The phantom shell is formed by gluing and fixing the upper panel 2, the lower panel 6 and the circular truncated cone target holder 8, a closed space is formed together with the sound window 3 on the side surface, a background imitated Tissue Material (TMM) 9 is filled in the closed space, the sound window 3 is connected with the upper panel 2 and the lower panel 6, the included angle range of the sound window 3 and the lower panel 6 is 60-90 degrees, the angle of the included angle is determined by the surface distance between the sound window 3 and the transducer and the longitudinal direction size of the transducer, and the angle avoids multiple reflection between the sound window 3 and the transducer. The acoustic window 3 is made of a polyester film material with the thickness of 50-100 mu m and is used for simulating the acoustic characteristics of human epidermal tissues.

As shown in fig. 3, the target is a diffuse scattering layer 7, which is disposed on the side surface of the circular truncated cone target holder 8, and the back surface of the target is closely attached to the circular truncated cone target holder 8, and the diffuse scattering layer 7 has a certain value which forms an inclination angle phi with the lower panel 6, and the inclination angle phi is generally in a range of 10 to 80 degrees. The diffuse scattering layer 7 is less than 1mm thick and is formed by coating a layer of substrate with a particulate acoustic diffuse scattering material. And has the effect of diffusely scattering incident sound waves.

As shown in fig. 1, a circular hole 5 is formed on the upper panel 2 at a side near the circular edge to serve as a passage for filling the background-like tissue material 9. The outside of the round hole 5 is pasted with a plugging rubber 4 with excellent elasticity, the material of the plugging rubber is a vacuum rubber, and the plugging rubber is used as an injection and air suction inlet during the maintenance of the imitated tissue material.

The background tissue-imitating material 9 is a material for imitating acoustic parameters of human soft tissues, the material is a water-based polymer gel matrix composite material, the sound velocity of an ultrasonic tissue-imitating material (TMM) is (1540 +/-10) m/s, the slope of the acoustic attenuation coefficient of the ultrasonic tissue-imitating (TM) material is (0.7 +/-0.05) dB/(cm & MHz), and the tissue-imitating material parameters are values measured under the condition that the temperature is [ (23 +/-3) DEG C ].

The tissue-imitating material 9 is a core part of the ultrasonic phantom, and the functional failure is caused by the variation of the composition, the state and the acoustic characteristics of the tissue-imitating material, the tissue-imitating material of the ultrasonic tissue-imitating phantom has maintainability, liquid contained in the tissue-imitating material can be evaporated and lost through gaps of a shell of the phantom, the tissue-imitating material can lose water and shrink after the phantom is used for a long time, and the phantom can be completely failed and cannot be recovered under the condition of severe water loss. The tissue-imitating material can be maintained daily by using special water-based maintenance liquid, and the water-based maintenance liquid can be injected by using an injection needle through the plugging rubber 4 on the upper panel 2; the aqueous maintenance liquid is specially prepared for the tissue-imitating material. The daily maintenance period is related to the temperature and humidity environment of the phantom. The service life of the phantom can be greatly prolonged by daily supplementing and maintaining liquid for maintenance.

Fig. 4 is a schematic diagram of the tissue phantom used for detecting the imaging performance of an ultrasonic tomography imaging device, and the whole structure is in a closed or semi-closed water tank, and degassing treatment is usually required. The apparatus in the embodiment uses a circular array transducer 10, i.e. the transducer is arranged in a partial or full circular arc. The phantom 1 is placed in water, typically with the lower panel 6 placed on a horizontal platform submerged in water. It is often necessary to have the water level of the water bath for ultrasonic coupling higher than the top panel of the phantom. The circle center of the phantom is ensured to be accurately coincided with the center of the annular array transducer 10, and measures are taken to remove bubbles attached to the acoustic window. Starting imaging equipment, setting the imaging equipment in a transmitting-receiving state of all array elements, adjusting the upper and lower positions of an ultrasonic probe, and enabling a radiation surface to be aligned with a phantom acoustic window to obtain a two-dimensional image of a material and a structure in a phantom;

as shown in fig. 5, when all array elements of the probe participate in imaging, a circular bright band formed by scattered light spots can be seen on the instrument screen; when only part of the probe array elements participate in imaging, only part of the annular bright band in the direction corresponding to the position of the active array element is presented on the instrument screen. And measuring the dimension d of the center of the bright band along the depth direction of the phantom by using an electronic vernier of the detected instrument, wherein the slice thickness at the depth pointed by the sound beam is as follows:

s＝d/tanφ＝d/φ

the probe was moved up and down so that the scanning beams were aligned with the target surfaces at detection depths (measured by using a phantom containing detection depth items) 1/2, 1/3, and 2/3, respectively, the dimension d in the depth direction of the center of each bright band was measured, and then the slice thickness s was calculated by using the above equation.

The method can measure the width of the bright band on each circumferential arc angle of the circular bright band formed by the scattered light spots, thereby comparing the slice thickness values of the circular array elements in each direction and quantitatively calculating the circumferential uniformity of the slice thickness.

After the test, the mold is taken out of the water and the water on the surface is wiped off by a soft towel or the like.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (9)

1. The utility model provides a imitative tissue phantom that is used for slice thickness detection of supersound tomography equipment qxcomm technology, its characterized in that, imitative tissue phantom is the round platform form, includes: a phantom housing, an acoustic window (3), a background tissue-mimicking material (9) and a target; the phantom shell is formed by fixing an upper panel (2), a lower panel (6) and a round table target seat (8) between the upper panel and the lower panel, the phantom shell and an acoustic window (3) stuck to the side surface of the round table form a closed space together, a background imitation tissue material (9) is filled in the closed space, and the target is a diffuse scattering layer (7) which is clung to and covers the side surface of the round table target seat (8); an inlet filled with a background tissue-imitating material (9) is arranged on the upper panel (2), and a plugging rubber is stuck on the inlet.

2. The simulated tissue phantom according to claim 1 wherein the material of the phantom housing is a rigid structural plastic.

3. The phantom according to claim 1, wherein the acoustic window (3) is a 50-100 μm thick polyester film.

4. The tissue-mimicking phantom according to claim 3, wherein the acoustic window (3) connects the upper panel (2) and the lower panel (6), and an angle between a tangent plane of the acoustic window (3) and the lower panel (6) ranges from 60 ° to 90 °.

5. The tissue phantom according to claim 1, wherein the background tissue mimicking material (9) is an aqueous polymer gel-based composite.

6. The tissue-imitating phantom according to claim 1, wherein the included angle between the tangent plane of the side surface of the circular truncated cone target holder (8) and the lower panel (6) ranges from 10 ° to 80 °.

7. The phantom according to claim 6, wherein the diffuse scattering layer (7) consists of a layer of particulate acoustic diffuse scattering material coated on a substrate, the thickness of which is less than 1 mm.

8. The tissue phantom as recited in claim 1, wherein the inlet of the upper panel (2) is a circular hole (5) arranged near the circumference, and is blocked by a blocking rubber (4), and the blocking rubber (4) is made of a vacuum rubber.

9. The phantom according to claim 8, wherein the background phantom material (9) is serviceable with a special care solution which is injected through the plugging rubber (4).

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