KR102703057B1 - Composition for realizing bone tissue of anthropomorphic phantom - Google Patents

Abstract

The present invention relates to a composition for implementing bone tissue of an anthropomorphic phantom for use as a human body replacement used for quality assurance (QA) of medical X-ray imaging devices, etc. The composition for implementing bone tissue of an anthropomorphic phantom according to the present invention can implement an HU value very similar to bone tissue using inexpensive materials, thereby enabling inexpensive manufacturing of expensive anthropomorphic phantoms and having the effect of import substitution.

Description

Composition for realizing bone tissue of anthropomorphic phantom

The present invention relates to a composition for implementing bone tissue of an anthropomorphic phantom for use as a substitute for a human body, used for quality assurance (QA) of medical radiological imaging devices, etc.

In general, medical equipment is becoming more advanced due to the development of science and technology. As a result, imaging devices that can observe the internal state of the human body in more detail are being developed and released. Such imaging devices include computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine imaging (SPECT), and positron emission tomography (PET).

However, images obtained from the above medical imaging devices are difficult for the general public to distinguish, and only highly trained and educated professionals can diagnose patient lesions through images. The discipline in which professionals interpret medical images and diagnose patients is called radiology.

The most basic examination in radiology is one that uses X-rays. In other words, an examination using X-rays is an examination that obtains an image by passing X-rays through the patient's body. In a X-ray photograph, the image is basically composed of X-ray dose and the absorption and scattering spectrum of the living body. The bioinformation obtained here is expressed as two-dimensional information through a conversion process (development) after passing through an imaging system and a recording system. The fidelity of the information obtained at this time is affected by the intensity and dose of the X-ray, the size of the focus, the physiological and physical movement of the subject, scattered rays, the sensitivity of the intensifying screen or film, the components of the drug in the developing process, the developing temperature, and the developing time.

Since medical images obtained by X-ray photography are determined by the radiation exposure dose and the penetration of the subject, it is necessary to maintain the quality of the X-ray source at a consistent level. Therefore, in conventional X-ray imaging devices and detectors, the quality assurance (QA) of the X-ray source is performed at regular intervals (e.g., 1 month, 3 months, 6 months, or 1 year). The quality assurance is performed using a structure called a phantom that replaces the human body as the subject instead of the patient.

Accordingly, when performing radiographic imaging using a human body replacement phantom as described above, it is possible to output image results that correspond to readable lesions in conjunction with the image analysis characteristics of the medical imaging device, and by supporting the quantification of the image results output as described above, it is possible to objectively define the interpretation level of the radiographic imaging device.

However, most of the human body replacement phantoms sold on the market depend on imports, and the price of one phantom is very high at around 100 million won, so the demand for inexpensive phantoms that can replace them is increasing.

Among the human body replacement phantoms, PLA (Poly Lactic Acid) is well known as a material for implementing soft tissue, and plaster is well known as a material for implementing bone tissue. However, there is a technical difficulty in implementing it in a way similar to the HU (Hounsfield Unit) value of actual human bone tissue.

Accordingly, the inventor of the present invention found a composition for implementing bone tissue to implement similarly to the HU value of actual human bone tissue, and completed the present invention.

Patent registration No. 10-1406630

The purpose of the present invention is to provide a composition for implementing bone tissue of an anthropomorphic phantom.

Another object of the present invention is to provide an anthropomorphic phantom comprising a composition for implementing bone tissue of an anthropomorphic phantom; a head anthropomorphic phantom; a head and neck anthropomorphic phantom; and a skull anthropomorphic phantom.

The purpose of the present invention is to provide a method for manufacturing the above-mentioned anthropomorphic phantom.

To achieve the above purpose,

The present invention is based on 42.5 parts by weight of plaster; and

Containing 5-9 parts by weight of PLA (Poly lactic acid);

A composition for implementing bone tissue of an anthropomorphic phantom is provided.

In one embodiment, the content of PLA (Poly lactic acid) based on 42.5 parts by weight of plaster is

It may preferably contain 6.75-8.25 parts by weight, more preferably 7.125-7.875 parts by weight, still more preferably 7.275-7.725 parts by weight, and particularly preferably 7.425-7.575 parts by weight.

The above gypsum and PLA content ratio is an important factor in obtaining an appropriate HU value in CT scanning when implementing bone tissue. If it is out of the above-described range, there may be a problem in reproducing an HU value similar to bone tissue.

The above composition may further contain water as a solvent. Since the water evaporates after the composition is cured, it may be a factor that does not significantly affect the physical properties of the composition.

In addition, the present invention provides an anthropomorphic phantom comprising a composition for implementing bone tissue of an anthropomorphic phantom; a head anthropomorphic phantom; a head and neck anthropomorphic phantom; and a skull anthropomorphic phantom.

Furthermore, the present invention comprises a step (step 1) of manufacturing a soft tissue molding using a 3D printer using a PLA (Poly lactic acid) filament; and

A step (step 2) of filling and hardening a composition for implementing bone tissue of the anthropomorphic phantom of claim 1 into the bone tissue region of the soft tissue molding manufactured in step 1 above;

Provides a method for manufacturing an anthropomorphic phantom.

The composition for implementing bone tissue of an anthropomorphic phantom according to the present invention can implement an HU value very similar to bone tissue using inexpensive materials, so that an expensive anthropomorphic phantom can be manufactured inexpensively and has the effect of import substitution.

Figure 1 shows a photograph (top) and a CT scan image of the expensive 'Rando phantom' sold commercially.
Figure 2 shows the results of measuring the HU value of a soft tissue molded article manufactured by controlling the infill value in the 3D printing molded article of the soft tissue region using PLA filament to find an infill value similar to the HU value of the soft tissue region of the Rando phantom.
Figure 3 is a photograph of a molded product of a soft tissue area manufactured through 3D printing with the PLA infill value set to 82%.
Figure 4 shows a CT image and HU value measurement results of a molded product of a soft tissue area manufactured through 3D printing with a PLA infill value set to 82%.
Figure 5 is a photograph of a conical tube filled with a composition for filling a bone tissue region prepared with the compositions of Examples 1-1 to 1-8.
Figure 6 shows the results of measuring the change in HU value over time by CT scanning of a conical tube in which the compositions of Examples 1-1 to 1-8 were cured.
Figure 7 is a photograph showing the process of filling a composition manufactured with the composition of Example 1-4 into the bone tissue region of a phantom molded product (regions 4 and 5) of the soft tissue region manufactured in Example 1.(1) and the completed anthropomorphic phantom.
Figure 8 is a photograph of the Rando Phantom; the anthropomorphic phantom with areas 4 and 5 replaced by Example 1; and the anthropomorphic phantom with areas 4 and 5 replaced by Comparative Example 2.
Figure 9 is a graph showing CT images of a Rando Phantom (Comparative Example 1); an anthropomorphic phantom (PLA + Plaster Phantom) replaced with Example 1 in areas 4 and 5; and an anthropomorphic phantom (PLA Phantom) replaced with Comparative Example 2 in areas 4 and 5; and HU values of areas corresponding to vertical lines and horizontal lines indicated in the CT images.
Figure 10 shows the process of scanning the Reference Rando phantom with CT to obtain a CT image and then 3D printing it through processes such as modeling.

This invention is intended to be a cheap replacement for the expensive commercially available anthropomorphic phantom, the 'Rando phantom'.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only intended to illustrate the present invention, and the content of the present invention is not limited to the following examples.

<Comparative Example 1> Preparation of a commercially available anthropomorphic phantom

The 'Rando phantom' (The Phantom Laboratory, Salem NY, USA), an anthropomorphic phantom sold at a high price on the market, was prepared as a standard for the anthropomorphic phantom to be reproduced in this invention (see Fig. 1). The 'Rando phantom' was taken by CT (Computed Tomography; Philips Medical, Eindhoven, Netherlands), and the HU (Hounsfield Unit) values of each soft tissue and bone tissue were measured, and the results are shown in Fig. 1.

CT setting: 120 kV, 200mA, 1 mm thickness scanned

slicer software: CURA (Ultimaker, Utrech, Netherlands)

Figure 1 shows a photograph (top) and a CT scan image of the expensive 'Rando phantom' sold commercially.

As shown in Figure 1,

In area 4 of 'Rando phantom', the HU (Hounsfield Unit) values of soft tissue and bone tissue were measured as -27 and 625, respectively.

In area 5 of the 'Rando phantom', the HU (Hounsfield Unit) values of soft tissue and bone tissue were measured as -20 and 684, respectively.

The HU (Hounsfield Unit) values of each of the soft tissue and bone tissue measured in the above Fig. 1 were used as verification values for the anthropomorphic phantom to be manufactured in this invention, and the HU value of the 'Rando phantom' bone tissue shows an HU value similar to that of actual bone tissue.

<Example 1> Manufacturing of an anthropomorphic phantom

(1) Manufacturing of molded products in soft tissue areas using 3D printing

First, it was confirmed in Fig. 1 that the HU value of the soft tissue area of 'Rando phantom' was approximately -20. Accordingly, the soft tissue area was manufactured in a cube shape using a 3D printer (Manufacturer: Ultimaker, Model name: Ultimaker S5, Country of manufacture: Netherlands) with different infill values using PLA (Poly Lactic Acid) filament, and the results of measuring the HU value according to the infill value are shown in Fig. 2.

Here, the PLA density of the molded product obtained through 3D printing is shown differently depending on the setting of the infill value.

Figure 2 shows the results of measuring the HU value of a soft tissue molded article manufactured by controlling the infill value in the 3D printing molded article of the soft tissue region using PLA filament to find an infill value similar to the HU value of the soft tissue region of the Rando phantom.

As shown in Fig. 2, it was confirmed that the infill value of 82% was most similar to the soft tissue area HU value of the Rando phantom.

Accordingly, the PLA infill value was set to 82% and Soft was printed through 3D printing. A molded product in the tissue area was manufactured.

Specifically, the Reference Rando phantom was scanned with CT to obtain the CT image as a DICOM (Digital imaging and Communication in Medicine) file, and this file was modeled using Mimics software (Materialise, Leuven, Belgium) based on the HU (Hounsfield units) value, and the ROI (Region of Interest) area was set according to the HU value using the Mimics program. In order to distinguish between soft tissue and bone tissue areas, the soft tissue area was set to the area from -500 HU to 200 HU, and the bone tissue area was set to 200 HU or more. Using a 3D printer, only the soft tissue area was modeled, and the area to be the bone tissue area was set as a blank space. The 3D model was converted to a SteroLithography (STL) file in Mimics software, and this STL file inputs the print conditions that the 3D printer can print into the slicer software CURA (Ultimaker, Utrecht, Netherlands). The file (ufp file) sliced through CURA was input into the 3D printer and the soft tissue area was printed.

Figure 10 shows the process of scanning the Reference Rando phantom with CT to obtain a CT image and then 3D printing it through processes such as modeling.

- 3D Printing Filaments and Conditions

Filament: PLA (density 1.24 g/cm3, Ultimaker, Utrech, Netherlands)

Printing condition: Nozzle 230 degrees, layer thickness 0.3 mm, printing speed 50 mm/s

Figure 3 is a photograph of a molded product of a soft tissue area manufactured through 3D printing with the PLA infill value set to 82%.

Figure 4 shows a CT image and HU value measurement results of a molded product of a soft tissue area manufactured through 3D printing with a PLA infill value set to 82%.

As shown in Fig. 4, the HU value of the soft tissue region molded product manufactured through 3D printing by setting the PLA infill value to 82% was 7 in region 4 and -13 in region 5, which was similar to the soft tissue region HU value of 'Rando phantom'.

For reference, in the field of anthropomorphic phantom technology, the HU values in the soft tissue region are in the range of approximately -500 to 200, and the HU values in the bone tissue region are in the range of approximately 200 or more.

(2) Preparation of a composition for filling a bone tissue region and injection of the composition into the bone tissue region of a phantom molded article of the soft tissue region prepared in (1) above.

In the above-described Fig. 1, the HU (Hounsfield Unit) value of bone tissue in area 4 of the 'Rando phantom' was measured as 625, and the HU (Hounsfield Unit) value of bone tissue in area 5 was measured as 684.

In order to find a composition for implementing a bone tissue region showing an HU value similar to that of the bone tissue region of 'Rando phantom', a composition was prepared with the composition shown in Table 1 below. Specifically, PLA (Poly Lactic Acid) powder (density 1.24 g/cm ³ ; Ultimaker, Utrech, Netherlands), plaster powder (density: 2.3 g/cm ³ ; SAMWOO CO., LTD, Seoul, Korea), and water were mixed with the composition shown in Table 1 below to prepare a composition for filling a bone tissue region. The prepared composition was filled into a conical tube to induce hardening, and the result is shown in Fig. 5.

Water : 24 g Plaster (g) PLA (g) PLA percent (%) Example 1-1 50.0 0.0 0 Example 1-2 47.5 2.5 5 Example 1-3 45.0 5.0 10 Example 1-4 42.5 7.5 15 Example 1-5 40.0 10.0 20 Example 1-6 37.5 12.5 25 Example 1-7 35.0 15.0 30 Example 1-8 32.5 17.5 35

Figure 5 is a photograph of a conical tube filled with a composition for filling a bone tissue region prepared with the compositions of Examples 1-1 to 1-8.

The conical tubes in which the compositions of Examples 1-1 to 1-8 prepared above were cured were subjected to CT scanning to measure the change in HU value over time, and the results are shown in Fig. 6.

Figure 6 shows the results of measuring the change in HU value over time by CT scanning of a conical tube in which the compositions of Examples 1-1 to 1-8 were cured.

As shown in Fig. 6, after approximately 60 days when sufficient curing was completed, the HU value of the composition for filling the bone tissue region manufactured with the composition of Example 1-4 (Plaster/PLA = 42.5/7.5) was in the range of 650-700, confirming that it exhibited a HU value similar to that of the bone tissue region of 'Rando phantom'.

Accordingly, in the phantom molding of the soft tissue region (regions 4 and 5) manufactured in the above (1), a composition manufactured with the composition of Example 1-4 was filled into the bone tissue region to manufacture an anthropomorphic phantom.

Figure 7 is a photograph showing the process of filling a composition manufactured with the composition of Example 1-4 into the bone tissue region of a phantom molded product (regions 4 and 5) of the soft tissue region manufactured in Example 1.(1) and the completed anthropomorphic phantom.

The HU values of the soft tissue and bone tissue in each of areas 4 and 5 of the 'Rando phantom' are compared in Tables 2 and 3 below with the HU values of the soft tissue and bone tissue in each of areas 4 and 5 of the anthropomorphic phantom manufactured by filling the composition manufactured with the composition of Example 1-4.

Rando Phantom (Area 4) soft tissue bone tissue mean (HU) SD mean (HU) SD -27 87 625 301 Anthropomorphic phantom manufactured in the example (area 4) soft tissue bone tissue mean (HU) SD mean (HU) SD -13 102 657 223

Rando Phantom (Area 5) soft tissue bone tissue mean (HU) SD mean (HU) SD -20 86 684 343 Anthropomorphic phantom manufactured in the example (area 5) soft tissue bone tissue mean (HU) SD mean (HU) SD 7 108 624 265

As shown in Tables 2 and 3 above, it can be confirmed that the HU values of the soft tissue and bone tissue of the anthropomorphic phantom manufactured in the example and the commercially available Rando Phantom are implemented similarly.

<Comparative Example 2> Manufacturing of Personified Phantom 2

As comparative example 2, a molded product of a soft tissue region using 3D printing manufactured in Example 1.(1) was prepared without filling the composition for filling the bone tissue region.

<Experimental Example 1> Comparative evaluation of CT scan images and HU values of the commercially available 'Rando phantom', the anthropomorphic phantom manufactured in Example 1, and the anthropomorphic phantom manufactured in Comparative Example 2

The purpose of this invention is to manufacture a low-cost anthropomorphic phantom domestically to replace the 'Rando phantom' that is sold at a high price on the market.

Accordingly, in Experimental Example 1, the following experiment was conducted to determine how similarly the anthropomorphic phantom manufactured in the example reproduced the HU values of each soft tissue and bone tissue of the 'Rando phantom'.

Specifically, areas 4 and 5 of the 'Rando phantom' were replaced with the phantoms manufactured in Example 1 and Comparative Example 2, respectively, to prepare anthropomorphic phantoms (see Fig. 8). Each of the three anthropomorphic phantoms prepared as shown in Fig. 8 was photographed using CT, and the HU values of the areas corresponding to the vertical and horizontal lines indicated in the photographed CT images were measured and compared, and the results are shown in Fig. 9.

Figure 8 is a photograph of the Rando Phantom; the anthropomorphic phantom with areas 4 and 5 replaced by Example 1; and the anthropomorphic phantom with areas 4 and 5 replaced by Comparative Example 2.

Figure 9 is a graph showing CT images of a Rando Phantom (Comparative Example 1); an anthropomorphic phantom (PLA + Plaster Phantom) replaced with Example 1 in areas 4 and 5; and an anthropomorphic phantom (PLA Phantom) replaced with Comparative Example 2 in areas 4 and 5; and HU values of areas corresponding to vertical lines and horizontal lines indicated in the CT images.

As shown in Fig. 9, looking at the captured CT image, it can be confirmed that similar to the bone tissue area being displayed in white in the Rando Phantom, the anthropomorphic phantom replaced with Example 1 in areas 4 and 5 also obtains a similar image. On the other hand, in the case of the anthropomorphic phantom replaced with Comparative Example 2 in areas 4 and 5, it can be confirmed that the white color corresponding to the bone tissue is not observed.

In addition, as shown in the graph measuring the HU values of the areas corresponding to the vertical and horizontal lines indicated on the captured CT image, it can be confirmed that the HU values of the Rando Phantom and the anthropomorphic phantom replaced with Example 1 in areas 4 and 5 are quite similar.

The present invention has been described with reference to preferred embodiments thereof. Those skilled in the art will appreciate that the present invention may be implemented in modified forms without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is not set forth in the foregoing description, but rather in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (12)

Based on 42.5 parts by weight of plaster; and
Containing 5-9 parts by weight of PLA (Poly lactic acid);
A composition for implementing bone tissue of an anthropomorphic phantom.
In the first paragraph,
Based on 42.5 parts by weight of plaster; and
Containing 6.75-8.25 parts by weight of PLA (Poly lactic acid);
A composition for implementing bone tissue of an anthropomorphic phantom.
In the second paragraph,
Based on 42.5 parts by weight of plaster; and
Containing PLA (Poly lactic acid) 7.125-7.875 parts by weight;
A composition for implementing bone tissue of an anthropomorphic phantom.
In the third paragraph,
Based on 42.5 parts by weight of plaster; and
Containing PLA (Poly lactic acid) 7.275-7.725 parts by weight;
A composition for implementing bone tissue of an anthropomorphic phantom.
In paragraph 4,
Based on 42.5 parts by weight of plaster; and
Containing PLA (Poly lactic acid) 7.425-7.575 parts by weight;
A composition for implementing bone tissue of an anthropomorphic phantom.
In the first paragraph,
A composition for implementing bone tissue of an anthropomorphic phantom, characterized in that it further contains water.
In Article 6,
A composition for implementing bone tissue of an anthropomorphic phantom, characterized in that the water evaporates after the composition is hardened.
An anthropomorphic phantom comprising a composition for implementing bone tissue of the anthropomorphic phantom of claim 1.
A head anthropomorphic phantom comprising a composition for implementing bone tissue of the anthropomorphic phantom of claim 1.
A head and neck anthropomorphic phantom comprising a composition for implementing bone tissue of the anthropomorphic phantom of claim 1.
A skull anthropomorphic phantom comprising a composition for implementing bone tissue of the anthropomorphic phantom of claim 1.
Step 1 of manufacturing a soft tissue molding using a 3D printer using PLA (Poly lactic acid) filament; and
A step (step 2) of filling and hardening a composition for implementing bone tissue of the anthropomorphic phantom of claim 1 into the bone tissue region of the soft tissue molding manufactured in step 1 above;
How to make an anthropomorphic phantom.