Patent Application
20250050574
The present invention relates to a 3D printing filament for medical imaging educational human equivalent bones with radiopaque that is most similar to human bones, and more specifically, to a 3D printing filament for medical imaging educational human equivalent bones with radiopaque that is most similar to a human bone, which allows stable and radiation-free computed tomography (CT) medical imaging examination and education using the computed tomography (CT) for medical images by mixing and drying barium sulfate with thermoplastic resin to obtain chips, melt-extruding, cooling and winding the obtained chips to create a filament, and manufacturing human equivalent phantoms (such as bones, skin, fat, soft tissue) through 3D printing of the wound filament.
As well known, computed tomography (CT) is a medical imaging device that scans the human body based on X-rays and visualizes images based on the density differences of each tissue structure.
Anatomical structures in the human body have different densities. When exposed to X-rays, the differences in absorption and penetration due to the density variations show the linear attenuation coefficient, and the attenuation coefficient can represent CT numbers in images. The range of CT Numbers is from −1000 to 3071. Lower CT Numbers indicate lower density materials appearing black in images, and higher CT Numbers indicate higher density appearing white in images. Furthermore, bones, which serve to protect and support internal organs, are the densest structures in the human body. Bone tissue is composed of cancellous bone (200 to 600HU) and cortical bone (600 to 1500HU), with the average CT Number of around 1000HU.
Meanwhile, with the rapid development of computed tomography (CT), the importance of diagnosis using CT has been increasing. CT is to perform examinations within a single breath-hold by reducing patient radiation dose and increasing scanning speed. For this, by using new materials in a detector, sensitivity to lower doses has been improved, thereby reducing the radiation exposure to patients and enhancing resolution.
Additionally, the diagnosis of three-dimensional lesions has become possible with two-dimensional images and three-dimensional reconstructed images, thereby increasing the utilization of CT. Thus, CT is reconstructed in a mathematical method using attenuated data passing through a subject to represent the internal structure of a section in images.
Furthermore, the acquisition of high-resolution images of bone structures and locomotor organs, such as the cardiovascular system, and the quality control of the CT have become possible. To accurately scan at one go, it is necessary to undergo examination by a skilled radiologist and radiologic technologist. However, in CT, primary radiation generated in the X-ray tube is projected onto the tissue through a collimator, which is a device that the focus of an object lens turns rays entering through a slit into parallel rays, in an optical instruments like a spectrometer. Since X-rays are continuously irradiated to the tissue while the X-ray tube rotates 360 degrees, the radiation dose is very high. Therefore, CT education and training are not feasible to apply to a real human body, so instead of the real human body, a human equivalent model must be used.
Therefore, since it is impossible to conduct CT imaging medical education by directly irradiating X-rays onto the human body, it is necessary to conduct image training using human equivalent bones that substitute for human bones. The kinds of human equivalent bones available for image training is limited, and the high cost of existing human equivalent bones presents difficulties in using the existing human equivalent bones for actual education. In addition, since there are no 3D printing filaments that satisfy CT numbers and material properties similar to human bones, it is impossible to replicate the color, texture, and similar CT number components of real human bones, so there are lots of problems in using the human equivalent phantoms for radiographic imaging education.
Additionally, since human equivalent bones capable of quantitatively measuring the image quality and the impact on radiation dose suitable for CT education and training similar to human bones have not been provided, there have been lots of limitation in CT education and training involving human equivalent phantoms.
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior arts, and it is an objective of the present invention to provide a new 3D printing filament for medical imaging educational human equivalent bones with radiopaque that is most similar to human bones, which allows stable and radiation-free computed tomography (CT) medical imaging examination and education using the computed tomography (CT) for medical images by mixing and drying barium sulfate with thermoplastic resin to obtain chips, melt-extruding, cooling and winding the obtained chips to create a filament, and manufacturing human equivalent bones that meet the material properties of the CT number through 3D printing of the wound filament.
To accomplish the above object, according to the present invention, there is provided a 3D printing filament for medical imaging educational human equivalent bones with radiopaque that is most similar to human bones, which is manufactured to print human equivalent bones of a human body model, wherein the filament capable of printing human equivalent bones is formulated by mixing and drying 1 to 8 parts by weight of medical-grade barium sulfate based on 100 parts by weight of thermoplastic resin in a mixing dryer to obtain chips, melt-extruding and cooling the obtained chips in a melt extruder and cooler to produce a filament, and winding the filament.
Moreover, the filament has a diameter of 1.75 mm to 2.85 mm.
Furthermore, the thermoplastic resin is composed of any one selected from PET copolymer, PLA, ABS, PP, PE, PC Nylon, POM, and PBT resin.
According to the present invention, the 3D printing filament for medical imaging educational human equivalent bones with radiopaque that is most similar to human bones has a new effect of allowing stable and radiation-free computed tomography (CT) medical imaging examination and education using the computed tomography (CT) for medical images by mixing and drying barium sulfate with thermoplastic resin to obtain chips, melt-extruding, cooling and winding the obtained chips to create a filament, and manufacturing human equivalent bones through 3D printing of the wound filament.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
To fully understand the present invention, preferred embodiments of the present invention are described with reference to the accompanying drawings.
The embodiments of the present invention can be varied in many forms, and the scope of the present invention should not be construed as being limited to the embodiments specifically described below. The embodiments are provided to more safely describe the present invention to a person having ordinary skill in the art.
Therefore, the shapes of components in the drawings may be exaggerated for clearer description. The same members in each drawing are indicated by the same reference numerals.
A 3D printing filament for medical imaging educational human equivalent bones according to the present invention will be described below with reference to an embodiment and experimental examples 1 and 2.
The present invention is configured to manufacture a filament for 3D printing of medical imaging educational human equivalent bones.
The filament capable of printing human equivalent bones is formulated by mixing and drying 1 to 8 parts by weight of medical-grade barium sulfate based on 100 parts by weight of thermoplastic resin in a mixing dryer to print human equivalent bones with various specific gravities.
A mixture in which 1 to 8 parts by weight of medical-grade barium sulfate is mixed into 100 parts by weight of thermoplastic resin is introduced into the mixing dryer, and then, is mixed and dried at 45 to 57° C. for 20 to 32 minutes. Chips obtained in the mixing/drying process are introduced into a melt extruder and cooler, in which the chips are melt extruded, cooled, and wound to produce a filament. Thereafter, the filament are wound to 300M (1 roll) standards to print bones.
Furthermore, it is preferable for the filament to have a diameter of 1.75 mm to 2.85 mm.
Additionally, the thermoplastic resin is preferably composed of any one selected from PET copolymer, PLA, ABS, PP, PE, PC Nylon, POM, and PBT resin.
Meanwhile, the human body is composed of a total of 206 bones, and human bones can be largely divided into seven skeletal parts according to the difference in bone density: skull, temporomandibular joint, shoulder joint, rib, elbow joint, hip joint, and femur.
Moreover, the internal structure of human bones mainly consists of joints, cartilage connecting the joints, periosteum with high density covering the bone surface, and the softer bone sponge inside the bone.
To print a human equivalent bone simulator of the same level as a real human bone by a 3D printer, it is necessary to use the three components, namely, cartilage, periosteum, and bone sponge, as described above.
Specifically, since the seven skeletal parts of the human body, namely, the skull, temporomandibular joint, shoulder joint, rib, elbow joint, hip joint, and femur, are different in strength, in the present invention, filaments with different specific gravities are produced, so that filaments with density and specific gravity suitable for the density and specific gravity of each skeletal part can be selected and output. For instance, for the relatively rigid skull, the part by weight of barium sulfate (MBaSO4) is increased, and the part by weight of PET copolymer is decreased, so that the specific gravity of bone can range from 1.78 to 1.89.
Additionally, in CT imaging, each pixel is represented by a CT number (HU), and according to the CT number (HU), the 3D printer can manufacture human equivalent phantoms using the filament.
All resins, metals, and non-metals have shielding properties, and the shielding degree (CT number) thereof varies. The most important property of the 3D printing filament is 3D printing processability.
Therefore, in manufacturing the 3D printing filament for medical imaging educational human equivalent bones according to the present invention, the selection of resin, metal, and non-metal materials with excellent 3D printing processability is important, and the mixability of resin, metal, and non-metal materials is also important.
Barium sulfate is a non-metal powder with relatively low density, and has excellent dispersibility when mixed with thermoplastic resin. The filament produced by melt-extrusion of the barium sulfate mixture also exhibited excellent processability in 3D printing.
PET copolymer, PLA resin, PET resin, PBT resin, ABS, Nylon, PC, PE, PP, and POM were prepared, and printed using an FDM type 3D printer. The 3D printer used was PRUSA MK3S (Czech PRUSA).
In CT imaging, each pixel were represented by CT number (HU), and a series of counting values for each pixel were measured.
In experimental example 1, based on resin weight values of F100% (Wt), a cylindrical specimen (PIN, Ø20×50 mm) was manufactured using the FDM type 3D printer (as shown in
To identify the CT Number for each material, cylinders of the materials were created and inserted into circular CT imaging plastic grooves (as shown in
In addition, a comparison of metal and non-metal shielding properties is shown in Table 2.
In case that the CT numbers of pure 100% metal materials (MaterialsFill) are higher than 3071HU, blurring is so severe that the image cannot be read, as shown in the CT image results below.
The comparison of resin shielding properties is shown in Table 3.
Moreover, a comparison of shielding properties (CT Number) of metals, non-metals, and plastic resins is shown in
As shown in
In experimental example 2, as shown in [Table 4], experimental examples 1 to 8 were conducted. The filament was processed by varying the weights of poly-lactic acid (PLA) resin and barium sulfate, fixing thermoplastic composite (TPS composite by PETELA) resin at 10%, and mixing them to a total weight value of 100% (Wt). The filament was printed by the FDM type 3D printer in 100% infill to produce a cylindrical specimen (PIN, Ø20×50 mm). Thereafter, an experiment was conducted to obtain CT Number values, deviations for each item were displayed.
The CT numbers for the amount of barium sulfate ranged from 200 to 2000HU, which were compatible with both cancellous bone (200 to 600HU) and cortical bone (600 to 1500HU) in CT resolution, and it was found that the printing processability was good.
In experimental example 2, as shown in [Table 5], experimental examples 1 to 8 were conducted.
Resin processing using an injector or an extruder does not require resin modification for improvement of resin processability due to the excellent processability of the injector or the extruder. However, by using the filament processed by mixing the mixture to a total weight value of 100% (Wt) while varying the weights of PP and barium sulfate, a cylindrical specimen (PIN, Ø20×50 mm) was produced by the FDM type 3D printer in 100% infill, and then, an experiment requiring CT number values was conducted, and deviations for each item were displayed.
Additionally, as shown in experimental example 2 [Table 5], by using the filament processed by mixing the mixture with total weight value of 100% (Wt), in which 96 weight % of PETELA IPS resin, which was a composition of PBT and PET, and 4 weight % of barium sulfate were mixed, a model of an artificial bone (Phantom) most similar to the human bone was printed by the FDM type 3D printer (100% infill & CT Number 1000HU). The model is illustrated in
As seen in
The embodiments of the present invention described above are merely illustrative, and those skilled in the art will recognize that various modifications and equivalents are possible from the embodiments. Therefore, the present invention should not be limited to the forms mentioned in the detailed description.
Therefore, the true technical scope of protection of the present invention should be determined by the technical spirit of the attached claims. Furthermore, the present invention should be understood to include all modifications, equivalents, and substitutes within the spirit and scope of the invention as defined by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0104083 | Aug 2023 | KR | national |
