Phantom used for verifying radiation dose for treatment and method for verifying radiation dose by using same

Abstract

The present invention relates to a phantom used for verifying a radiation dose for treatment and a method for verifying a radiation dose by using same. The phantom according to the present invention comprises: an outer case forming an inner space; and multiple detection points for detecting the dose of incident radiation. The multiple detection points comprise: a radiation detection panel three-dimensionally arranged in the inner space; and a driving circuit board positioned in the inner space and connected to the radiation detection panel.

Description

Phantom used for verification of radiation dose for treatment and method for verification of radiation dose using the same The present invention relates to a phantom used for verifying radiation dose for treatment and a method for verifying radiation dose using the same. Various radiation therapy techniques are being introduced, and precise treatment is required to deliver the minimum dose to the normal tissues around the tumor and the exact prescribed radiation dose to the tumor by calculating with precise and optimized dose distribution. For such accurate treatment, it is important to verify the calculated radiation dose before treatment. Various dosimetry equipment is used for this purpose, but it is insufficient to verify the three-dimensional radiation dose. Accordingly, the purpose of the present invention is to provide a phantom used for verifying radiation dose for treatment and a method for verifying radiation dose using the phantom. The above object of the present invention is achieved by providing a phantom used for verifying radiation dose for treatment, comprising: an outer case forming an internal space; a radiation detection panel including a plurality of detection points for detecting the dose of incident radiation, the plurality of detection points being arranged in three dimensions in the internal space; and a driving circuit board positioned in the internal space and connected to the radiation detection panel. The above radiation detection panel is flexible, and the radiation detection panel can be rolled into a cylindrical shape or rolled into a spiral shape. The radiation detection panel may include an electrically insulating layer having an upper surface and a lower surface; an upper electrode on the upper surface of the electrically insulating layer; and a plurality of pixel units electrically connected to the electrically insulating layer and in direct contact with the lower surface of the electrically insulating layer. The above radiation detection panel may include a first radiation detection panel rolled into a cylindrical shape; and a second radiation detection panel rolled into a cylindrical shape and positioned within the first radiation detection panel. An inner cover positioned between the first radiation detection panel and the second radiation detection panel and preventing interference between the first radiation detection panel and the second radiation detection panel may be further included. It further includes an integrated circuit connecting the above radiation detection panel and the circuit board, and the circuit board can be connected to an external power line and signal line. The above radiation detection panel may include a first radiation detection panel in the form of a flat plate; and a second panel spaced apart from the first radiation detection panel and having a different area from the first radiation detection panel. The above internal space may be cylindrical in shape. The above object of the present invention is achieved by providing a method for verifying a radiation dose, comprising: a step of irradiating a phantom including a radiation detection panel with radiation; and a step of analyzing the radiation dose using the radiation detected by the radiation detection panel, wherein the radiation detection panel includes a plurality of detection points for detecting the dose of incident radiation, and the plurality of detection points are arranged in three dimensions in the internal space. The above phantom forms a cylindrical internal space, the radiation detection panel is placed within the internal space, and the radiation can be irradiated 360 degrees along the perimeter of the internal space. The above radiation detection panel is flexible, and the radiation detection panel can be rolled into a cylindrical shape or rolled into a spiral shape. The above radiation detection panel may include a first radiation detection panel rolled into a cylindrical shape; and a second radiation detection panel rolled into a cylindrical shape and positioned within the first radiation detection panel. The radiation may include at least one of X-rays and proton rays. The above verification method can be used to verify the radiation dose of volumetric intensity-controlled rotational therapy. According to the present invention, a phantom used for verifying radiation dose for treatment and a method for verifying radiation dose using the phantom are provided. Figure 1 is a perspective view of a phantom according to a first embodiment of the present invention. Figure 2 is an exploded perspective view of a phantom according to the first embodiment of the present invention. FIG. 3 illustrates a radiation detection panel and an integrated circuit in a phantom according to the first embodiment of the present invention. Fig. 4 shows a cross-section along line IV-IV' of Fig. 1, Figure 5 illustrates the measurement principle of a flexible panel in a phantom according to the first embodiment of the present invention. Figure 6 is an exploded perspective view of a phantom according to a second embodiment of the present invention. Figure 7 is a cross-sectional view of a phantom according to a second embodiment of the present invention. Figure 8 is a cross-sectional view of a phantom according to a third embodiment of the present invention. Figure 9 is a cross-sectional view of a phantom according to the fourth embodiment of the present invention. Figures 10 and 11 illustrate a method for verifying radiation dose using the phantom of the present invention. The present invention will be described in more detail with reference to the drawings below. The attached drawings are merely examples provided to further illustrate the technical concepts of the present invention, and therefore, the scope of the present invention is not limited to the attached drawings. For the purpose of illustration, the thickness and length of each part in the attached drawings may be exaggerated. A phantom according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a perspective view of a phantom according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of a phantom according to the first embodiment of the present invention, FIG. 3 shows a radiation detection panel and an integrated circuit in a phantom according to the first embodiment of the present invention, FIG. 4 shows a cross-section taken along line IV-IV' of FIG. 1, and FIG. 5 shows a measurement principle of a flexible panel in a phantom according to the first embodiment of the present invention. The phantom (1) includes a case (11, 12), a radiation detection panel (20), an integrated circuit (30), and a circuit board (40). The phantom (1) is cylindrical in shape overall and extends in one direction. In other embodiments, the phantom (1) may have various shapes, such as a square pillar. Cases (11, 12) form the exterior of the phantom (1) and include a main body case (11) and a lower case (12). Cases (11, 12) are made of a thin plate. Cases (11, 12) may be made of, but are not limited to, reinforced plastic, and in particular, may be made of carbon fiber reinforced plastic (CRFP). A joining hole (111, 121) is formed in the case (11, 12), a passage hole (122) is formed in the center of the lower case (12), and a joining protrusion (123) is formed protruding around the upper surface of the lower case (12). Cases (11, 12) form an internal space, and the internal space has a cylindrical shape. In other embodiments, the internal space may have various shapes, such as a square column. The internal space houses a radiation detection panel (20), an integrated circuit (30), and a circuit board (40). In Fig. 2, for convenience, the diameters of the radiation detection panel (20), the integrated circuit (30), and the circuit board (40) are depicted as being similar to those of the case (11, 12). The radiation detection panel (20) has a flexible characteristic and is in the form of a cylindrical plate as shown in Fig. 3. The radiation detection panel (20) is arranged so that its movement within the internal space is restricted. The radiation detection panel (20) includes a plurality of detection points that detect the dose of incident radiation, and the plurality of detection points are arranged three-dimensionally in the internal space. In the present embodiment, the detection points are distributed cylindrically according to the cylindrical state of the radiation detection panel (20). The radiation detection panel (20) includes an upper electrode (210), an electrical insulation layer (220), and a charge collection electrode (230), as shown in FIG. 5, and further includes a charge collection amplifier (240), a transistor (250), and a storage capacitor (260). The upper electrode (210) may be formed by sputtering deposition and / or adhesion, and may be formed of any conductive material, such as a metal. Examples of the electrical insulation layer (220) include, but are not limited to, organic compounds containing low-Z materials (e.g., chemical elements having a low atomic number of protons in the nucleus), such as hydrogen (H), oxygen (O), carbon (C), nitrogen (N), and fluorine (F), such as polytetrafluoroethylene (TEFLON) and acrylic resin. Examples of preferred materials for the electrical insulation layer (220) include parylene, benzocyclobutene (BCB), and polyimide film (KAPTON), which have high dielectric strength. Vacuum deposition can be used for parylene, and adhesion can be used for either parylene or KAPTON, preferably by preparing a film tape having a thickness of 50 microns. In Fig. 5, the capacitor represents the capacitance of the electrical insulation layer (220) and the storage capacitor (260). When irradiating the phantom (1), the upper electrode (210) is disposed on the upper surface of the electrical insulation layer (220), and the charge collection electrode (230) as a pixel unit is disposed on the lower surface of the electrical insulation layer (220). In one embodiment, the charge collection electrode (230) as a pixel unit is disposed on the lower surface of the electrical insulation layer (220) within the electrical insulation layer (220). In one embodiment, the pixel units are electrically connected to the electrical insulation layer (220), and at least one transistor is connected to each pixel unit such that the pixel units are disposed on the lower surface of the electrical insulation layer (220). Each transistor is connected between one of the charge collection electrodes (230) and ground, and the electron collection electrodes (230) may be located within the lower surface of the electrical insulation layer (220). In another embodiment, the pixel unit includes a charge collection electrode (230), a storage capacitor (260), and

[0028] A transistor (250) may be included. The charge collection electrode (230) collects a charge signal in a pixel area of ​​the electrical insulation layer (220). A storage capacitor (260) is connected to the charge collection electrode (230) to store the charge signal collected by the charge collection electrode (230). A field effect transistor (FET) (250) is connected to the charge collection electrode (230) and acts as a switch between the storage capacitor (260) and an external charge integration amplifier (240). When radiation is applied, when a charged particle crosses the dielectric layer (220), the continuous ionization along its path forms a conductive channel that allows current to be conducted from the bias electrode (210) to the pixel electrode (230). This conductive channel opens only when the charged particle crosses the dielectric layer (220). In contrast, the photo-electric interaction of an X-ray or gamma-ray photon with the dielectric layer (220) creates a group of electron-hole pairs that are localized at the point of interaction. Even with an electric field between the bias electrode and the pixel electrode, the charge separation and mobility of the electron-hole pairs in the dielectric layer (220) are limited, and therefore, the interaction of multiple X-ray or gamma-ray photons at adjacent locations in the pixel is required to create a conductive path that allows current to be conducted from the bias electrode to the pixel electrode. The pixel matrix can be arranged in multiple rows and multiple columns, such as N rows × M columns. The gate lines of the transistors in each row are connected to each of a plurality of external gate drivers. The data lines of the transistors in each column orthogonal to the gate lines are connected to each of a plurality of charge-integrating amplifiers. Before exposure to a radiation beam, a bias voltage having a magnitude not exceeding the breakdown voltage of the electrical insulator is applied to the upper electrode (210), and a negative voltage is applied to all the gate electrodes of the pixel FET transistors. During exposure to a radiation beam, the ionization channel current of the insulating layer (220) increases in proportion to the intensity or dose of the radiation. The local ionization channel charge on each pixel is stored in a storage capacitor (260). During the readout of an image resulting from exposure to a radiation beam, the gate voltage in one row (row 1, row 2 or row 3) is converted from a negative value to a positive value, causing the charge stored in each pixel in that row to be transferred through the orthogonal data lines to the respective charge-integrating amplifiers, where it is then digitized by a processing computer (see Fig. 11). After the data for one row of the matrix is ​​completed, the potential of the gate lines of that row returns to a negative value, and the FET transistors return to the "Off" state. The potential of the next row of gate lines is converted from a negative value to a positive value, causing the stored charge to flow to the orthogonal charge-integrating amplifiers. This process will be repeated alternately until all the charges in the pixel matrix have been read out. In one embodiment, the pixel unit array is directly bonded to the electrically insulating layer (220) without an intervening layer for a radiation converter having a charge generation material (CGM), such as amorphous selenium, or without a photoconductive layer for converting X-ray energy into electron-hole pairs. When a thin layer of electrically insulating material without a layer of selenium is used, the charge generation efficiency due to the photoelectric effect, the interaction of photons with the insulating material, is typically 100 times lower than the charge generation efficiency due to the interaction of photons with selenium. However, when exposed to particle beam radiation, charges passing through the ionization channel exhibit lower order charge trapping or changes in local electric fields that affect subsequent imaging, while maintaining high spatial resolution. In the radiation detection panel (20) described above, each pixel may correspond to a detection point. In addition, since the radiation detection panel (20) must be flexible, the radiation detection panel (20) can use, for example, a flexible plastic substrate. An integrated circuit (30) connects a radiation detection panel (20) to a circuit board (40). The integrated circuit (30) may use a readout integrated circuit. The integrated circuit (30) is a high-speed multi-channel analog-to-digital converter (ADC) used for the purpose of collecting charges classified by pixel within the panel. The direct circuit (30) may include the direct amplifier (240) of FIG. 5. The direct circuit (30) may be included in the circuit board (40), and may be configured separately from the circuit board (40) as shown in the drawing to maximize the signal-to-noise ratio. The circuit board (40) is in the shape of a circular plate, but is not limited thereto. The circuit board (40) is connected to the radiation detection panel (20) through an integrated circuit (30), and is connected to an external power line and signal line (such as a LAN cable) through a through hole (122). The measurement results of the radiation detection panel (20) are transmitted to the outside through the signal line. Each of the components described above is joined through a joining hole (41, 111, 121), a joining member (91, screw, etc.) and a joining protrusion (123), and a detailed description of the joining is omitted. The internal space of the phantom (1) may be filled with water or solid water. The solid water may be, but is not limited to, an epoxy resin-based material. A phantom according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. Fig. 6 is an exploded perspective view of a phantom according to a second embodiment of the present invention, and Fig. 7 is a cross-sectional view of a phantom according to a second embodiment of the present invention. The following is a description focusing on a different configuration from the first embodiment. A phantom (1) according to the second embodiment includes a first radiation detection panel (20a) and a second radiation detection panel (20b). Both the first radiation detection panel (20a) and the second radiation detection panel (20b) are rolled into a cylindrical shape, and as shown in Fig. 7, the second radiation detection panel (20b) is positioned within the first radiation detection panel (20a) (multi-panel layering structure). Additionally, an inner cover (50) is positioned between the first radiation detection panel (20a) and the second radiation detection panel (20b) to prevent interference between the two panels and to fix the positions of the panels. However, in Fig. 7, for convenience, the diameters of the first radiation detection panel (20a), the second radiation detection panel (20b), and the inner cover (50) are depicted as being similar. In another embodiment, the first radiation detection panel (20a), the second radiation detection panel (20b), and the inner cover (50) may be arranged in close contact with each other. The main body case (11) and inner cover (50) each have a joining hole (112, 51). According to the second embodiment, the detection points of the radiation detection panels (20a, 20b) are arranged more densely within the internal space. In another embodiment, three or more radiation detection panels (20) may be provided. The shape of the radiation detection panel (20) can be modified in various ways, and this is explained with reference to FIGS. 8 and 9. FIG. 8 is a cross-sectional view of a phantom according to a third embodiment of the present invention, and FIG. 9 is a cross-sectional view of a phantom according to a fourth embodiment of the present invention. In the third embodiment, the radiation detection panels (20) are arranged in a spiral shape (spirally rolled). According to the third embodiment, detection points can be densely arranged within the internal space with a small number of radiation detection panels (30). In the fourth embodiment, a plurality of flat-shaped radiation detection panels (20a, 20b, 20c, etc.) are arranged (stacked) in parallel, and the width or area of ​​the radiation detection panels (20a, 20b, 20c, etc.) is provided in various ways. The phantom according to the present invention described above has detection points arranged three-dimensionally within its internal space. Because it utilizes radiation detection panels with multiple detection points, it is easy to provide a large number of detection points and easily understand measurement results. Furthermore, when the radiation detection panels are arranged in a cylindrical or spiral shape, detection points can be effectively arranged in a three-dimensional space using only a small number of radiation detection panels. The cylindrical 3D phantom according to the present invention is similar to a patient body model, and the beam vector is maintained constant regardless of the angle during rotational radiotherapy, and 3D dosimetry is possible. Hereinafter, a method for verifying radiation dose using a phantom of the present invention will be described with reference to FIGS. 10 and 11. Radiation therapy is a leading cancer treatment method that uses high-energy radiation (such as X-rays, gamma rays, or protons) from devices to destroy cancer cells and halt their growth. Because radiation can affect both cancer and healthy cells, it's crucial to deliver the desired dose to the tumor while minimizing the amount of radiation delivered to normal tissue. With the introduction of advanced radiation therapy technologies such as Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT), precise treatment is required, with precise and optimized dose distributions calculated to deliver minimal dose to surrounding normal tissue and concentrated radiation to the tumor. Therefore, verifying the calculated dose before treatment is crucial. In clinical practice, quality assurance (QA) is implemented for both radiation therapy equipment and patient care. VMAT (Volume Intensity Modulated Rotational Therapy) is a three-dimensional intensity-modulated radiotherapy technique that utilizes a rapidly rotating beam 360 degrees. This technique has recently gained widespread popularity, enhancing treatment accuracy while minimizing radiation exposure to surrounding normal tissue. Rotational therapy can be used not only with X-rays but also with proton therapy. Cutting-edge treatment technologies require precise treatment, making treatment planning and dose calculations more complex. Comparative verification of the three-dimensional radiation dose distribution applied to tumors and organs, tailored to the patient's anatomy, is crucial. 3D dosimetry is very necessary to reduce errors and improve treatment effects, and the phantom of the present invention can be used, in particular, to verify radiation dose of VMAT (volumetric intensity-modulated rotation therapy). As shown in Figure 10, in the treatment of tumors and other conditions using radiation, a treatment decision is made first, followed by a simulation. A treatment plan is then established, and the radiation dose according to the plan is verified. After verification, the actual treatment is administered, followed by follow-up treatment. The phantom of the present invention can be used to verify radiation dose in this process. In verification, a phantom is first set up at the measurement location and connected to a LAN cable. Next, the phantom, which includes a radiation detection panel, is irradiated with radiation, and the radiation detected by the radiation detection panel is used to analyze the radiation dose. The phantom is filled with water or solid water to simulate the human body. Furthermore, radiation detection panels are arranged three-dimensionally within the phantom's interior, allowing radiation doses to be monitored at various points within the interior. Radiation can be irradiated 360 degrees around the phantom, i.e., along the perimeter of the cylindrical interior space. This allows data on the irradiated beam to be collected without any angle restrictions. Furthermore, 360-degree measurement is possible, making it suitable for verifying treatment devices that rotate 360 ​​degrees while performing treatment. The radiation may include, but is not limited to, at least one of X-rays, gamma rays, and proton rays. The above-described embodiments serve as illustrative examples of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate the potential for various modifications and implementations of the present invention. Therefore, the technical scope of the present invention should be defined by the appended claims.

Claims

1. In the phantom used to verify the radiation dose for treatment, An outer case that forms an inner space; A radiation detection panel comprising a plurality of detection points for detecting the dose of incident radiation, wherein the plurality of detection points are arranged in three dimensions in the internal space; and A phantom including a driving circuit board located in the above internal space and connected to the above radiation detection panel.

2. In paragraph 1, The above radiation detection panel is flexible, The above radiation detection panel is a phantom that is rolled into a cylindrical shape or a spiral shape.

3. In paragraph 2, The above radiation detection panel, An electrical insulating layer having an upper surface and a lower surface; an upper electrode on the upper surface of the electrical insulating layer; and A phantom comprising a plurality of pixel units electrically connected to the electrical insulating layer and in direct contact with a lower surface of the electrical insulating layer.

4. In paragraph 3, The above radiation detection panel, A first radiation detection panel rolled into a cylindrical shape; and A phantom comprising a second radiation detection panel that is cylindrically rolled and positioned within the first radiation detection panel.

5. In paragraph 4, Located between the first radiation detection panel and the second radiation detection panel, A phantom further comprising an inner cover for preventing interference between the first radiation detection panel and the second radiation detection panel.

6. In paragraph 5, It further includes an integrated circuit connecting the above radiation detection panel and the above circuit board, The above circuit board is a phantom connected to external power lines and signal lines.

7. In paragraph 1, The above radiation detection panel, A first radiation detection panel in the form of a flat plate; and A phantom comprising a second panel spaced apart from the first radiation detection panel and having a different area from the first radiation detection panel.

8. In paragraph 1, The above inner space is a cylindrical phantom.

9. In the method of verifying radiation dose, A step of irradiating a phantom including a radiation detection panel with radiation; and A step of analyzing radiation dose using radiation detected from the above radiation detection panel is included. The above radiation detection panel includes a plurality of detection points that detect the dose of incident radiation, and the plurality of detection points are arranged three-dimensionally in the internal space.

10. In paragraph 9, The above phantom forms a cylindrical internal space, The above radiation detection panel is placed within the internal space, A method in which the above radiation is irradiated 360 degrees along the perimeter of the above internal space.

11. In paragraph 10, The above radiation detection panel is flexible, The above radiation detection panel is rolled into a cylindrical shape or a spiral shape.

12. In paragraph 11, The above radiation detection panel, A first radiation detection panel rolled into a cylindrical shape; and A method comprising a second radiation detection panel that is cylindrically rolled and positioned within the first radiation detection panel.

13. In paragraph 11, A method wherein the radiation comprises at least one of X-rays and proton rays.

14. In paragraph 11, The above verification method is a method used to verify the radiation dose of volumetric intensity-controlled rotational therapy.

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