CN114699062A

CN114699062A - Electrical impedance tomography model, experimental device and method

Info

Publication number: CN114699062A
Application number: CN202210383984.0A
Authority: CN
Inventors: 林志敏; 桑岭; 陆彧; 刘医军; 王海广; 周静; 王颖治; 钟南山
Original assignee: Dianqi Biomedical Technology Beijing Co ltd; Guangzhou Institute Of Respiratory Health Guangzhou Institute Of Respiratory Diseases; Guangzhou National Laboratory
Current assignee: Dianqi Biomedical Technology Beijing Co ltd; Guangzhou Institute Of Respiratory Health Guangzhou Institute Of Respiratory Diseases; Guangzhou National Laboratory
Priority date: 2022-04-12
Filing date: 2022-04-12
Publication date: 2022-07-05

Abstract

The embodiment of the disclosure discloses an electrical impedance tomography model, an experimental device and a method. Wherein, electrical impedance tomography model includes: the three-dimensional printing method comprises a three-dimensional printing chest bone model, a lung model and a heart model, wherein the chest bone model, the lung model and the heart model are combined according to corresponding anatomical positions in a human body, the resistivity of the chest bone model is a first resistivity and is used for simulating the resistivity of the chest of the human body, the resistivity of the lung model is a second resistivity and is used for simulating the resistivity of the lung of the human body, and the resistivity of the heart model is a third resistivity and is used for simulating the resistivity of the heart of the human body, so that the accurate three-dimensional printing chest bone model, the lung model and the heart model are obtained, and the model is enabled to be more in line with the real anatomical structure of the human body. The method can also accurately simulate different resistivities of different organs and the resistivity of the same organ under different excitation signals, and carry out three-dimensional accurate modeling on the resistivity of the human chest.

Description

Electrical impedance tomography model, experimental device and method

Technical Field

The disclosure relates to the field of medical instruments, in particular to an electrical impedance tomography model, an experimental device and a method.

Background

Electrical Impedance Tomography (EIT) measures corresponding body surface voltage while exciting safe current through an electrode set arranged on the chest of a human body, and then obtains a dynamic image capable of reflecting the distribution of Electrical Impedance in the chest according to a corresponding image reconstruction algorithm by using excitation and measurement data.

Because normal alveoli of a human body have higher resistivity under the condition of inflation, EIT can observe the ventilation condition of the lung in real time beside a bed, thereby reflecting the physiological or pathological state of the breathing of the human body. However, because the EIT signal of the human body is relatively weak, it is a basic element of EIT imaging to establish an accurate data acquisition system and an image reconstruction algorithm.

At present, in the field of respiratory EIT, a generally accepted method for measuring the accuracy of an EIT data acquisition system and an image reconstruction algorithm is to perform data measurement and image reconstruction experiments by using a physical model and further analyze indexes such as signal-to-noise ratio of data or images. Therefore, the accurate physical model experimental device is established, and the method has important significance for the evaluation and improvement of the EIT data measurement system and the image reconstruction algorithm.

However, most of the present EIT physical thoracic models have two major disadvantages: firstly, only lung tissues are considered, and the influence of other thoracic cavity tissues (heart, bone structures and the like) on EIT is ignored; secondly, although the prior art is also disclosed by a similar three-dimensional construction model technology, the following important defects also exist: 1. one prior art method disclosed is to 3D print the left and right lungs into non-solid hollow tissue; this results in the electrical resistivity of the lungs being equivalent to the electrical impedance of air; the actual physiological structure of the lung is abnormally complex and is divided into the lung parenchyma and the lung interstitium; only the lung parenchyma resembles a cavity structure; the resistivity in the case of total lung inflation is much less than that of air. 2. Another prior art method disclosed contemplates the use of a mixture of materials to construct thoracic organ tissue; but the resistivity of the designed target organ is too large and exceeds the normal range of the human body. Therefore, a physical model experiment device which has a three-dimensional structure and can reflect the real shape and resistivity characteristics of each visceral organ in the thoracic cavity is required in the field. The physical model experimental device established in a standardized mode can be used for calibration of an EIT data acquisition system and an image reconstruction algorithm, or used for clinical teaching and the like.

Disclosure of Invention

In order to solve the problems in the related art, embodiments of the present disclosure provide an electrical impedance tomography model, an experimental apparatus, and a method.

In a first aspect, an embodiment of the present disclosure provides an electrical impedance tomography model, including:

a three-dimensionally printed thorax skeleton model, a lung model and a heart model,

the chest bone model, the lung model and the heart model are combined according to the corresponding anatomical positions in the human body,

the resistivity of the thoracic skeleton model is a first resistivity and is used for simulating the resistivity of the thoracic cavity of a human body,

the resistivity of the lung model is a second resistivity for simulating the resistivity of the lungs of the human body,

and the resistivity of the heart model is a third resistivity and is used for simulating the resistivity of the heart of the human body.

With reference to the first aspect, the present disclosure provides, in a first implementation form of the first aspect,

the thoracic bone model, the lung model and the heart model are obtained by the following steps:

carrying out three-dimensional reconstruction on a computed tomography image of a human body to obtain a three-dimensional reconstruction model;

segmenting, repairing, smoothing and debugging the three-dimensional reconstruction model to obtain a computer three-dimensional printing model;

and carrying out three-dimensional printing based on the computer three-dimensional printing model to obtain the thoracic skeleton model, the lung model and the heart model.

With reference to the first aspect, the present disclosure provides in a second implementation form of the first aspect,

the thoracic cavity skeleton model, the lung model and the heart model are made of a mixture of acrylonitrile-butadiene-styrene copolymer and carbon black.

With reference to the second implementation manner of the first aspect, in a third implementation manner of the first aspect,

the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the sternum in the thoracic cavity bone model is a first mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the rib in the thoracic cavity bone model is a second mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the vertebra in the thoracic cavity bone model is a third mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the lung model is a fourth mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the heart model is a fifth mixing ratio.

With reference to the third implementation manner of the first aspect, in a fourth implementation manner of the first aspect,

the first mixing ratio is 4.46 +/-0.22: 1; and/or

The second mixing ratio is 4.01 plus or minus 0.20: 1; and/or

The third mixing ratio is 4.09 +/-0.20: 1; and/or

The fourth mixing ratio is 3.84 +/-0.19: 1; and/or

The fifth mixing ratio is 3.82 ± 0.19: 1.

In a second aspect, an experimental apparatus is provided in an embodiment of the present disclosure, which includes:

an electrical impedance tomography model according to any one of claims 1-5;

an insulating container in which the electrical impedance tomography model is fixed;

an electrode group fixed to an inner surface of the insulating container;

and the conductive solution is contained in the insulating container and submerges the electrical impedance tomography model.

With reference to the second aspect, the present disclosure provides, in a first implementation form of the second aspect,

the insulating container includes: an elliptic cylindrical container of organic glass, and/or

The wall thickness of the insulating container is 4.95-5.05 mm, and/or

The height of the insulating container is 396 and 404 mm, and/or

The length of the inner major axis of the ellipse of the insulating container is 346.5-353.5 mm, and/or

The length of the inner short axis of the ellipse of the insulating container is 297 and 303 mm.

With reference to the second aspect, the present disclosure provides, in a second implementation form of the second aspect,

the number of layers of the electrode group is a first value, the number of electrodes in each layer is a second value, and the electrodes in each layer are uniformly distributed on the inner surface of the insulating container.

With reference to the second implementation manner of the second aspect, in a third implementation manner of the second aspect,

the first value is 2 and the second value is 16.

With reference to the third implementation manner of the second aspect, in a fourth implementation manner of the second aspect,

the first layer electrode group corresponds to the fourth fifth intercostal position of the electrical impedance tomography model,

the second layer of electrode sets was 100 mm higher than the first layer of electrode sets.

With reference to the second aspect, the present disclosure provides, in a fifth implementation form of the second aspect,

the conductive solution is physiological saline.

With reference to the second aspect, the present disclosure, in a sixth implementation form of the second aspect,

further comprising:

and the sliding rheostat group is electrically connected with the electrode group.

In a third aspect, the present disclosure provides a method for constructing an electrical impedance tomography model experimental apparatus, including:

acquiring a computed tomography image of a human body;

performing three-dimensional reconstruction according to the computed tomography image to obtain a three-dimensional reconstruction model;

performing three-dimensional printing based on the computer three-dimensional printing model to obtain a thoracic skeleton model, a lung model and a heart model;

and combining the thoracic skeleton model, the lung model and the heart model to obtain the electrical impedance tomography model.

With reference to the third aspect, in a first implementation manner of the third aspect, the present disclosure further includes:

constructing an insulating container holding an electrode group, the electrode group being fixed to an inner surface of the insulating container;

fixing the electrical impedance tomography model in the insulating container;

and adding a conductive solution into the insulating container, wherein the conductive solution submerges the electrical impedance tomography model.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects:

according to the technical scheme provided by the embodiment of the disclosure, the electrical impedance tomography model comprises: the three-dimensional printing method comprises a three-dimensional printing chest bone model, a lung model and a heart model, wherein the chest bone model, the lung model and the heart model are combined according to corresponding anatomical positions in a human body, the resistivity of the chest bone model is a first resistivity and is used for simulating the resistivity of the chest of the human body, the resistivity of the lung model is a second resistivity and is used for simulating the resistivity of the lung of the human body, and the resistivity of the heart model is a third resistivity and is used for simulating the resistivity of the heart of the human body, so that the accurate three-dimensional printing chest bone model, the lung model and the heart model are obtained, and the model is enabled to be more in line with the real anatomical structure of the human body.

Moreover, the resistivity of different organs of the real human body is different, and the resistivity of the same organ under the excitation signals of different frequencies is also different. And the ABS/CB with different mixing ratios accurately simulates different resistivities of the thoracic bones, the heart and the lung, and can also simulate different resistivities of the same organ such as the lung under excitation signals with different frequencies. Therefore, the resistivity of the human breast is modeled accurately in three dimensions, an EIT data acquisition system and an image reconstruction algorithm are conveniently calibrated and evaluated, and the method can be conveniently used for other purposes such as clinical teaching and the like.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

Other features, objects, and advantages of the present disclosure will become more apparent from the following detailed description of non-limiting embodiments when taken in conjunction with the accompanying drawings. In the drawings:

FIG. 1 illustrates a three-dimensional printed electrical impedance tomography model according to an embodiment of the present disclosure;

FIG. 2 illustrates an experimental setup housing an electrical impedance tomography model according to an embodiment of the present disclosure;

FIG. 3 shows a flow diagram of a method of fabricating an electrical impedance tomography model according to an embodiment of the present disclosure;

FIG. 4 shows a flow diagram of a method of fabricating an electrical impedance tomography model experimental apparatus according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. Also, for the sake of clarity, parts not relevant to the description of the exemplary embodiments are omitted in the drawings.

In the present disclosure, it is to be understood that terms such as "including" or "having," etc., are intended to indicate the presence of labels, numbers, steps, actions, components, parts, or combinations thereof disclosed in the present specification, and are not intended to preclude the possibility that one or more other labels, numbers, steps, actions, components, parts, or combinations thereof are present or added.

It should also be noted that the embodiments and labels in the embodiments of the present disclosure may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

However, the current EIT physical thoracic cavity models have two major drawbacks: firstly, only lung tissues are considered, and the influence of other thoracic cavity tissues (heart, bone structure and the like) on EIT is ignored; and secondly, only considering the condition of a thoracic cavity fault, only constructing a single-layer lung physical model, and neglecting the basic fact that EIT current is distributed in a field and thoracic cavity organs are of three-dimensional structures. Therefore, a physical model experiment device which has a three-dimensional structure and can reflect the real shape and resistivity characteristics of each visceral organ in the thoracic cavity is required in the field. The physical model experimental device established in a standardized mode can be used for calibration of an EIT data acquisition system and an image reconstruction algorithm, or used for clinical teaching and the like.

In order to solve the above problems, the present disclosure provides an electrical impedance tomography model, an experimental apparatus and a method.

FIG. 1 illustrates a three-dimensional printed electrical impedance tomography model according to an embodiment of the present disclosure.

It will be understood by those of ordinary skill in the art that FIG. 1 illustrates a three-dimensional printed electrical impedance tomography model without limiting the present disclosure.

As shown in fig. 1(a), 1(b), and 1(c), the three-dimensional printed (3D printed) electrical impedance tomography model includes: a 3D printed thoracic skeleton model 103, a lung model 101 and a heart model 102.

As shown in fig. 1(D), the thoracic skeleton model 103, the lung model 101 and the heart model 102 are combined into a complete 3D printed electrical impedance tomography model 100 according to the corresponding anatomical positions of the human body by means of, for example, gluing.

In the embodiment of the present disclosure, the thoracic bone model 103, the lung model 101 and the heart model 102 may be formed by Fused Deposition Modeling (FDM) 3D printing technology, using Acrylonitrile Butadiene Styrene (ABS)/CB) materials with different mixing ratios, and 3D printing. The electrical resistivity of the chest bone model 103, the lung model 101 and the heart model 102 are different and are used for simulating the real electrical resistivity characteristics of each organ of the human body. The thorax includes 1 sternum, 12 pairs of ribs and 12 vertebrae according to the human anatomy. The sternum, ribs and vertebrae may be printed separately with different blend ratios of ABS/CB material to achieve different resistivity characteristics.

In the embodiment of the present disclosure, the thoracic skeleton model 103, the lung model 101, and the heart model 102 in fig. 1 are obtained in the following manner.

First, a spiral Computed Tomography (CT) is used to model a human body, for example, an adult male with a height of 170 cm, a weight of 70 kg, an age of 30 years, no smoking history or chest disease history is selected as a standard object according to the average value of Chinese resident nutritional and chronic disease status reports (2020). The advantage of adopting the standardized model which is completely matched with the human anatomy structure and the resistivity characteristic is that for the electrical impedance imaging systems designed by different groups, a unified and standardized performance evaluation platform which is closest to the real condition of the human body can be formed, and electrical impedance imaging evaluation errors caused by the manufacturing difference or insufficient precision of the model are avoided. The scan range includes the entire thorax. The scanning layer is 0.5 mm to 1 mm thick, for example 0.625 mm thick, and the number of scanning layers is 678 layers. CT images are saved in a standard DICOM format.

And secondly, after introducing the chest CT image by using MIMICS software, respectively carrying out computer three-dimensional reconstruction on the model to obtain a three-dimensional reconstruction model.

And finally, performing segmentation, error checking, repairing, smoothing and other operations on the heart, lung and thoracic cavity skeleton system models aiming at the three-dimensional reconstruction model to respectively generate the computer three-dimensional printing models of the heart, lung and thoracic cavity which can be printed in a 3D mode.

In the embodiment of the present disclosure, the "segmentation" operation is to determine which target organs are in the image of the CT three-dimensional reconstruction model, and the general method is the region growing method + manual segmentation. The "repair" operation is to obtain the target organ, and some organs have one or more missing parts due to the error of the CT image, and this needs to be corrected, for example, by manually repairing, filling, and deleting the part. "smoothing" is to smooth the surface of the target organ, since the three-dimensional reconstructed organ surface is generally not smooth, which facilitates 3D printing. The "smoothing" process may be a selection of a suitable filter in the software, such as gaussian low pass filtering. "error-checking" is the final comparison of the target organ with the original CT image to ensure that there is not too much difference. For example, the processing method is to manually adjust in software and compare CT images layer by layer for error checking.

In the embodiment of the disclosure, the ABS/CB mixing ratio of the printing material is respectively determined according to the resistivity characteristics of the heart, the lung and the thoracic bones. For example, for a resistivity at 50kHz, sternum is predominantly cortical, the resistivity is approximately 48.4 Ω m, and the ABS: CB (v/v) ═ 4.46 ± 0.22: 1; the ribs are mainly spongy bone, the resistivity is about 12.0 omega m, and the ABS ratio CB (v/v) is 4.0 +/-0.201: 1; the electrical resistivity of spinal bone is about 14.0 Ω m, ABS: CB (v/v) ═ 4.09 ± 0.20: 1; resistivity in the lung inflated state is about 9.7 Ω m, ABS: CB (v/v) ═ 3.84 ± 0.19: 1; the resistivity of the heart is about 5.1 Ω m, and ABS: CB (v/v) ═ 3.82 ± 0.19: 1. In the disclosed embodiment, a 10cm × 10cm × 10cm cubic structure can be printed with the above formulation as a reference; resistivity property measurements were made on the printed cubes to ensure that the measured resistivity values were substantially consistent with the resistivity values of the target organ (error < 5%).

In the embodiment of the present disclosure, a lung model 101 shown in fig. 1(a), a heart model 102 shown in fig. 1(b), and a thoracic bone model 103 shown in fig. 1(c) may be printed according to the ABS/CB blending ratio and assembled to obtain an electrical impedance tomography model 100 shown in fig. 1 (d). The spatial resistivity distribution of real organs of the human body is simulated more truly by 3D printing the chest cavity, the lung and the heart by using ABS/CB with different mixing ratios.

In the disclosed embodiment, the electrical resistivity of the chest, lungs, heart may be different for different frequencies of the excitation signal. The frequency of the excitation signal versus resistivity at 500ml tidal volume is shown in the table below.

In the embodiment of the present disclosure, for the heart resistivity, the lung resistivity and the chest resistivity at different excitation signal frequencies, 3D printing can be performed to simulate by using ABS/CB with different mixing ratios, so as to obtain a set of electrical impedance tomography models 100.

FIG. 2 shows an experimental setup housing an electrical impedance tomography model according to an embodiment of the present disclosure.

It will be understood by those of ordinary skill in the art that FIG. 2 illustrates an experimental setup that houses an electrical impedance tomography model, and does not constitute a limitation of the present disclosure.

Fig. 2a and 2b show an experimental set-up that can accommodate the electrical impedance tomography model 100 described above and can be connected to an EIT measuring instrument. An electrical impedance tomography model 100 (not shown in fig. 2) is fixed in a container 201 to construct a standard model for EIT apparatus calibration.

In the disclosed embodiment, the container 201 is in the shape of an elliptical cylinder, which is rapidly molded from plexiglas. The container wall thickness is 4.95-5.05 mm, e.g. 5 mm; the container height is 396 and 404 mm, for example 400 mm; the length of the major axis in the ellipse is 346.5-353.5 mm, for example 350 mm; the length of the minor axis in the ellipse is 297 and 303 mm, for example 300 mm. The container base 204 is a cuboid with a length of 400mm, a width of 350mm and a height of 10 mm. Two parallel electrode sets 202 and 203 are fixed on the inner surface of the container, the electrode set 203 is positioned between the fourth and fifth ribs of the model 100, and the electrode set 202 is 100 mm higher than the electrode set 203; the electrode is silver, the thickness is 0.4mm, the diameter is 12.0mm, and the purity is 99.99%. The

electrode groups

202 and 203 have 16 electrodes that are equally spaced and distributed on the same level. One side of the electrode is welded by copper wires with the purity of 99.99 percent and the diameter of 3 mm, and the copper wires penetrate through a drilling hole on the inner side wall of the container 201 to be connected with a shielding wire on the outer side of the container 201. And coating conductive adhesive on one side of the electrode welding copper wire, and applying pressure to make the electrode tightly adhered to the inner side wall of the container. The 16 shield wires outside the container are all provided with carbon fiber shield layers, the length of each shield wire is 200cm, and the shield wires are sleeved with metal shield nets after being wound in a crossed mode. Each shield wire is connected to a sliding rheostat 205 having a maximum resistance of, for example, 1M Ω, to simulate electrode-skin contact impedance, thereby minimizing simulation errors to the electrical impedance tomography model.

In an embodiment of the present disclosure, saline may be injected into the container 201 and the electrical impedance tomography model 100 is submerged for simulating the electrical impedance of the skin.

One of ordinary skill in the art will appreciate that the dimensions of the container 201 and container base 204 may be other dimensions as well, and the present disclosure is not limited thereto. The number of electrode groups may also be 1, 3, or other number of layers, which is not limited in this disclosure. The number of electrodes per layer may also be 12, or 20, or other numbers, which the present disclosure does not limit.

In the embodiment disclosed by the invention, the thoracic skeleton model, the lung model and the heart model which are consistent with the real appearance and the resistivity value are adopted, so that the real situation of human body measurement is more approximate, and the error of an experimental device is greatly reduced; the high-purity silver electrode reduces the influence of polarization potential; the lead adopts a shielding wire, is wound in a cross way and is shielded by a shielding net, so that the influence of electromagnetic interference is reduced; the shielding wire is externally connected with a slide rheostat which can imitate the contact resistance of the electrode and the skin; the container is filled with physiological saline to simulate skin impedance. The invention realizes the three-dimensional accurate simulation of the resistivity of each organ, skin and the like of the human chest, establishes the EIT resistivity standard model of the human chest, and is suitable for a data acquisition system and an imaging algorithm for evaluating the respiratory EIT.

In an embodiment of the present disclosure, as shown in fig. 1, an electrical impedance tomography model 100 includes: the 3D-printed thoracic skeleton model 103, lung model 101, and heart model 102 are combined in accordance with the corresponding anatomical positions in the human body to become the electrical impedance tomography model 100.

The electrical resistivity of the thoracic bone model is a first electrical resistivity, for example, for 50kHz, the sternum is dominated by compact bone, and the electrical resistivity is about 48.4 ohm-m; the ribs are mainly spongy bone, and the resistivity is about 12.0 omega m; the electrical resistivity of the spinal bone is about 14.0 Ω m, which is used to simulate the electrical resistivity of the human thorax.

The resistivity of the lung model is a second resistivity, for example, the resistivity of the lung in an inflated state is about 9.7 Ω m, and is used for simulating the resistivity of the lung of the human body. The resistivity of the heart model is a third resistivity, for example about 5.1 Ω m, for simulating the resistivity of the heart of a human body.

According to an embodiment of the present disclosure, by an electrical impedance tomography model, comprising: the three-dimensional printing method comprises a chest bone model, a lung model and a heart model which are printed in a three-dimensional mode, wherein the chest bone model, the lung model and the heart model are combined according to corresponding anatomical positions in a human body, the resistivity of the chest bone model is a first resistivity and is used for simulating the resistivity of the chest of the human body, the resistivity of the lung model is a second resistivity and is used for simulating the resistivity of the lung of the human body, and the resistivity of the heart model is a third resistivity and is used for simulating the resistivity of the heart of the human body, so that the model is more in line with the real anatomical structure of the human body, and the resistivity of organs of the human body is simulated.

Moreover, the resistivities of different organs of a real human body under the same frequency are different, and the resistivities of the same organ under excitation signals of different frequencies are also different. And the ABS/CB with different mixing ratios accurately simulates different resistivities of the thoracic bones, the heart and the lung, and can also simulate different resistivities of the same organ such as the lung under excitation signals with different frequencies. Therefore, the resistivity of the human breast is modeled accurately in three dimensions, an EIT data acquisition system and an image reconstruction algorithm are conveniently calibrated and evaluated, and the method can be conveniently used for other purposes such as clinical teaching and the like.

In an embodiment of the present disclosure, as previously described, the thoracic bone model 103, the lung model 101, and the heart model 102 are obtained by: three-dimensionally reconstructing a computed tomography image of a human body of an adult male, such as 170 cm in height, 70 kg in weight, 30 years old, no smoking history, no history of chest disease, to obtain a three-dimensional reconstruction model; segmenting, repairing, smoothing and debugging the three-dimensional reconstruction model to obtain a computer three-dimensional printing model; and performing three-dimensional printing based on the computer three-dimensional printing model to respectively obtain a chest skeleton model 103, a lung model 101 and a heart model 102.

In the embodiment of the present disclosure, the "segmentation" operation is to determine which target organs are in the image of the CT three-dimensional reconstruction model, and the general method is the region growing method + manual segmentation. The "repair" operation is to obtain the target organ, and some organs have one or more missing parts due to the error of the CT image, and this needs to be corrected, for example, by manually repairing, filling, and deleting the part. "smoothing" is to smooth the surface of the target organ, since the three-dimensional reconstructed organ surface is generally not smooth, which facilitates 3D printing. The "smoothing" process may be a selection of a suitable filter in software, such as gaussian low pass filtering. "error checking" is the final comparison of the target organ with the original CT image to ensure that there is not too much difference. For example, the processing method is manually adjusted in software, and the CT images are compared layer by layer for error checking.

According to the embodiment of the disclosure, the chest bone model, the lung model and the heart model are obtained by the following steps: carrying out three-dimensional reconstruction on a computed tomography image of a human body to obtain a three-dimensional reconstruction model; segmenting, repairing, smoothing and debugging the three-dimensional reconstruction model to obtain a computer three-dimensional printing model; and performing three-dimensional printing based on the three-dimensional printing model of the computer to obtain a thoracic cavity skeleton model, a lung organ model and a heart model so as to obtain the accurate three-dimensional printed thoracic cavity skeleton model, lung organ model and heart model.

In the embodiment of the disclosure, the material of the thoracic bone model, the lung model and the heart model is a mixture of acrylonitrile-butadiene-styrene copolymer and carbon black. The resistivity characteristics of different organs are realized by different ABS/CB mixing ratios.

According to the embodiment of the disclosure, the thoracic cavity bone model, the lung model and the heart model are made of the mixture of acrylonitrile-butadiene-styrene copolymer and carbon black, so that the resistivity of different organs can be accurately simulated.

In the disclosed embodiment, as described above, the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the sternum in the thoracic bone model is the first mixing ratio; the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the rib in the thoracic cavity skeleton model is a second mixing ratio; the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the vertebra in the thoracic cavity bone model is a third mixing ratio; the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the lung model is a fourth mixing ratio; the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the heart model was the fifth mixing ratio.

According to the disclosed embodiment, the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black passing through the sternum in the thoracic bone model is a first mixing ratio; and/or the volume mixing ratio of acrylonitrile-butadiene-styrene copolymer and carbon black of the rib in the rib cage bone model is a second mixing ratio; and/or the volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and the carbon black of the vertebra in the thoracic bone model is a third mixing ratio; and/or the lung model acrylonitrile-butadiene-styrene copolymer and carbon black have a volume mixing ratio of a fourth mixing ratio; and/or the acrylonitrile-butadiene-styrene copolymer and the carbon black of the heart model are mixed in a volume ratio of the fifth mixing ratio, thereby realizing accurate simulation of the resistivity of different organs.

In the disclosed embodiment, the first mixing ratio is 4.46 ± 0.22:1, simulating a sternum resistivity of 48.4 Ω m at 50kHz, as previously described; the second mixing ratio is 4.01 +/-0.20: 1, and the simulated rib resistivity is 12.0 omega m; the third mixing ratio is 4.09 +/-0.20: 1, and the simulated spinal bone resistivity is 14.0 omega m; the fourth mixing ratio is 3.84 +/-0.19: 1, and the resistivity of the simulated lung in an inflated state is 9.7 omega m; the fifth blend ratio was 3.82 + -0.19: 1, simulating a resistivity of 5.1 Ω m for the heart.

According to an embodiment of the disclosure, the first mixing ratio is 4.46 ± 0.22: 1; and/or the second mixing ratio is 4.01:1 ± 0.20; and/or the third mixing ratio is 4.09 ± 0.20: 1; and/or the fourth mixing ratio is 3.84 ± 0.19: 1; and/or the fifth mixing ratio is 3.82 ± 0.19:1, thereby achieving accurate simulation of the resistivity of each organ.

In an embodiment of the present disclosure, as set forth above with respect to fig. 2, an experimental setup comprising: an electrical impedance tomography model 100; an insulating container 201, in which the electrical impedance tomography model 100 is fixed; an electrode group 205 fixed to an inner surface of the insulating container 201; and the conductive solution is contained in the insulating container 201 and immerses the electrical impedance tomography model 100.

According to this disclosed embodiment, through an experimental apparatus, its characterized in that includes: an electrical impedance tomography model; the electrical impedance tomography model is fixed in the insulating container; an electrode group fixed to an inner surface of the insulating container; and the conductive solution is contained in the insulating container and immerses the electrical impedance tomography model, so that the resistivity of the chest of the human body is accurately simulated.

According to an embodiment of the present disclosure, by an insulating container comprising: the wall thickness of the plexiglass elliptic cylindrical container and/or the insulating container is 4.95-5.05 mm, the height of the insulating container is 396-404 mm, the length of the inner major axis of the ellipse of the insulating container is 346.5-353.5 mm, and/or the length of the inner minor axis of the ellipse of the insulating container is 297-303 mm, so that an electrical impedance tomography model is well accommodated.

In the embodiment of the present disclosure, the number of layers of the electrode group is a first value, for example, 2 layers; the number of electrodes in each layer is a second value, for example 16, the electrodes in each layer being uniformly distributed on the inner surface of the insulating container.

According to the embodiment of the disclosure, the number of the electrode groups is a first value, the number of the electrodes in each layer is a second value, and the electrodes in each layer are uniformly distributed on the inner surface of the insulating container, so that the resistivity is accurately measured.

According to the embodiment of the disclosure, the first layer electrode group corresponds to the fourth and fifth intercostal positions of the electrical impedance tomography model, and the second layer electrode group is 100 mm higher than the first layer electrode group, so that the resistivity is accurately measured.

According to the embodiment of the disclosure, the conducting solution is physiological saline, so that the resistivity of the skin is accurately simulated.

In the disclosed embodiment, after the electrodes are connected to the shielding wires, the shielding wires are connected to the sliding rheostat 205 with a maximum resistance of, for example, 1M Ω, as described above, so as to simulate the electrode-skin contact impedance

According to the embodiment of the present disclosure, by further comprising: and the sliding rheostat group is electrically connected with the electrode group, so that the contact impedance of the electrode and the skin is accurately simulated.

FIG. 3 shows a flow diagram of a method of fabricating an electrical impedance tomography model according to an embodiment of the present disclosure.

As shown in fig. 3, the flow of the method for making the electrical impedance tomography model includes: steps S301, S302, S303, S304, S305.

In step S301, a computed tomography image of a human body is acquired.

In step S302, three-dimensional reconstruction is performed according to the computed tomography image, so as to obtain a three-dimensional reconstruction model.

In step S303, the three-dimensional reconstruction model is segmented, repaired, smoothed, and checked for errors, so as to obtain a three-dimensional printing model of the computer.

In step S304, three-dimensional printing is performed based on the three-dimensional printing model of the computer, and a chest model, a lung model, and a heart model are obtained.

In step S305, the chest model, the lung model, and the heart model are combined, resulting in an electrical impedance tomography model.

According to an embodiment of the present disclosure, by acquiring a computed tomography image of a human body; performing three-dimensional reconstruction according to the computed tomography image to obtain a three-dimensional reconstruction model; segmenting, repairing, smoothing and debugging the three-dimensional reconstruction model to obtain a computer three-dimensional printing model; performing three-dimensional printing based on the three-dimensional printing model of the computer to obtain a thoracic skeleton model, a lung model and a heart model; and combining the thoracic skeleton model, the lung model and the heart model to obtain an electrical impedance tomography model, thereby obtaining an accurate three-dimensional electrical impedance tomography model.

As shown in fig. 4, the flow of the method for manufacturing the electrical impedance tomography model experiment apparatus includes the steps S301 to S305 which are the same as those of fig. 3, and further includes the steps of: s401, S402, S403.

In step S401, an insulating container to which an electrode group is fixed is constructed, and the electrode group is fixed to an inner surface of the insulating container.

In step S402, the electrical impedance tomography model is fixed in an insulating container.

In step S403, a conductive solution is added to the insulating container, and the conductive solution immerses the electrical impedance tomography model.

According to the embodiment of the present disclosure, by further comprising: constructing an insulating container holding an electrode group, the electrode group being fixed to an inner surface of the insulating container; fixing the electrical impedance tomography model in an insulating container; and adding a conductive solution into the insulating container, and immersing the electrical impedance tomography model by the conductive solution, thereby realizing the accurate simulation of the three-dimensional electrical impedance tomography model.

The foregoing description is only exemplary of the preferred embodiments of the disclosure and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention in the present disclosure is not limited to the specific combination of the above-mentioned features, but also encompasses other embodiments in which any combination of the above-mentioned features or their equivalents is possible without departing from the inventive concept. For example, the above features and the technical features disclosed in the present disclosure (but not limited to) having similar functions are replaced with each other to form the technical solution.

Claims

1. an electrical impedance tomography imaging model, is characterized in that, comprises:

3D printed thoracic skeleton model, lung model and heart model,

The thoracic bone model, lung model and heart model are combined according to the corresponding anatomical positions in the human body,

The resistivity of the thoracic bone model is the first resistivity, which is used to simulate the resistivity of the thoracic cavity of the human body,

The resistivity of the lung model is the second resistivity, which is used to simulate the resistivity of the human lung,

The resistivity of the heart model is the third resistivity, which is used to simulate the resistivity of the human heart.

2. The model of claim 1, wherein

The thoracic bone model, lung model and heart model are obtained by the following methods:

3D reconstruction of the computed tomography image of the human body to obtain a 3D reconstruction model;

Segmenting, repairing, smoothing, and checking errors on the three-dimensional reconstructed model to obtain a computer three-dimensional printing model;

Three-dimensional printing is performed based on the computer three-dimensional printing model to obtain the thoracic skeleton model, the lung model and the heart model.

3. The model of claim 1, wherein

The materials of the thoracic bone model, the lung model and the heart model are a mixture of acrylonitrile-butadiene-styrene copolymer and carbon black.

4. The model of claim 3, wherein

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and carbon black of the sternum in the thoracic skeleton model is the first mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and carbon black of the ribs in the thoracic skeleton model is the second mixing ratio; and/or

The volume mixing ratio of acrylonitrile-butadiene-styrene copolymer and carbon black of the vertebrae in the thoracic bone model is the third mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and carbon black of the lung model is the fourth mixing ratio; and/or

The volume mixing ratio of the acrylonitrile-butadiene-styrene copolymer and carbon black of the heart model is the fifth mixing ratio.

5. The model of claim 4, wherein

the first mixing ratio is 4.46±0.22:1; and/or

the second mixing ratio is 4.01±0.20:1; and/or

the third mixing ratio is 4.09±0.20:1; and/or

the fourth mixing ratio is 3.84±0.19:1; and/or

The fifth mixing ratio is 3.82±0.19:1.

6. An experimental device, characterized in that, comprising:

The electrical impedance tomography model according to any one of claims 1-5;

an insulating container, in which the electrical impedance tomography model is fixed;

an electrode group, fixed on the inner surface of the insulating container;

A conductive solution, contained in the insulating container, immerses the electrical impedance tomography phantom.

7. The device of claim 6, wherein

The insulating container includes: plexiglass elliptical cylindrical container, and/or

The insulating container has a wall thickness of 4.95-5.05 mm, and/or

The height of the insulating container is 396-404 mm, and/or

The length of the inner short axis of the ellipse of the insulating container is 297-303 mm.

8. The device of claim 6, wherein

9. The device of claim 8, wherein

The first value is 2 and the second value is 16.

10. The device of claim 9, wherein:

The electrode group of the first layer corresponds to the fourth and fifth intercostal positions of the electrical impedance tomography model,

The second layer electrode group is 100 mm higher than the first layer electrode group.

11. The apparatus of claim 6, wherein

The conductive solution is physiological saline.

12. The apparatus of claim 6, further comprising:

The sliding varistor group is electrically connected with the electrode group.

13. A method for constructing an electrical impedance tomography model experimental device, comprising:

Obtaining computed tomography images of the human body;

Perform three-dimensional reconstruction according to the computed tomography image to obtain a three-dimensional reconstruction model;

3D printing is performed based on the computer 3D printing model to obtain a thoracic skeleton model, a lung model and a heart model;

The thoracic bone model, the lung model and the heart model are combined to obtain an electrical impedance tomography model.

14. The method of claim 13, further comprising:

constructing an insulating container with an electrode set fixed on the inner surface of the insulating container;

Fixing the electrical impedance tomography model in the insulating container;

A conductive solution is added to the insulating container, and the conductive solution immerses the electrical impedance tomography model.