JP2016061735A - Radioactive-ray irradiation range detector and radioactive-ray irradiation detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a dose distribution check before implementing radiotherapy to be simply carried out.SOLUTION: A plurally of radioactive-ray irradiation range detectors 1 are prepared that has a polymer gel sheet internally arranged, is formed of transparent resin, and is composed of a transparent holding member having a stacking mechanism part for arranging the radioactive-ray irradiation range detector with the radioactive-ray irradiation range detectors vertically stacked. Then, in a state where a plurality of radioactive-ray irradiation range detectors 1 is stacked by the stacking mechanism part, radioactive-ray is irradiated. In this case, the polymer gel sheet gets cloudy in responce to an irradiation state of the radioactive-ray. The radioactive-ray irradiation range detector 1 getting cloudy is checked by a visual observation, or the plurality of radioactive-ray irradiation range detectors 1 are read by a scanner with the radioactive-ray irradiation range detectors separated one by one, and from the cloudy state of each of the read polymer gel sheets, a detection of the radioactive-ray irradiation state is carried out.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a radiation irradiation range detector used for confirmation of a radiation treatment plan and the like, and a radiation irradiation range detection method using the radiation irradiation range detector.

  As a treatment method for cancer patients, a radiation treatment method is widely used. In the radiotherapy method, a radiotherapy apparatus that irradiates a patient's lesion with radiation is used. By irradiating a patient's lesion with radiation using a radiotherapy device, cancer cells in the lesion are destroyed, leading to treatment.

Usually, when performing radiotherapy, treatment is performed in the order of the following step 1 to step 4.
Step 1: Confirmation of the lesion site Using a CT scanner or an MRI apparatus, a process for three-dimensionally grasping the size, position, and shape of the lesion site of the patient is performed.
Step 2: Treatment plan The direction, intensity, position, range, and the like when irradiating the lesion of the size and shape confirmed in Step 1 are determined using dedicated software on the computer device.
・ Step 3: Confirmation of dose distribution To confirm the irradiation state when the affected area confirmed in step 1 is irradiated with radiation in the treatment plan created in step 2, a dosimeter is attached to a model such as a human body. Irradiate the model with radiation.
Step 4: Start of radiotherapy If there is no problem in the irradiation state in the dose distribution confirmation in step 3, the patient's lesion is irradiated with the treatment plan created in step 2. This irradiation is performed several times to several tens of times depending on the size of the lesion and the progress of cancer.

  Here, the dose distribution confirmation in step 3 is important in accurately performing the treatment in step 4. In other words, when the lesion is irradiated with the irradiation plan determined in the treatment plan in step 2, it is confirmed whether the radiation is irradiated with an appropriate intensity to all the lesions as calculated in advance. There is a need to. In addition, it is necessary to confirm in the same manner whether or not the irradiation of radiation to a non-lesional part is minimal. If radiation is irradiated to a portion that is not a lesion, normal cells are destroyed, which is not preferable for treating the lesion.

  A film dosimeter is known as a method for confirming this dose distribution. The film dosimeter changes the color of the film where the radiation is irradiated. By determining the discoloration state, a doctor or engineer who performs radiation therapy can confirm the radiation irradiation state. However, in the conventional film dosimeter, the discoloration state is difficult to see visually, and after the image of the film dosimeter is taken into a computer device by a scanner, the discoloration state is emphasized by image processing. I was checking.

JP 2012-2669 A

With conventional film dosimeters, it is difficult to visually confirm the irradiation state of radiation, and polymer gel dosimeters have been developed as dosimeters to make it easy to visually confirm the irradiation state of radiation. Yes. Patent Document 1 describes an example of this polymer gel dosimeter.
A polymer gel dosimeter is a dosimeter in which a monomer is dispersed in a gel, and when irradiated with radiation, the monomer is polymerized to produce a polymer, which causes the gel to become cloudy and measure the dose from the degree of cloudiness. It is. Since the gel becomes cloudy, the region actually irradiated with radiation can be visualized. Moreover, since the polymer formed in proportion to the radiation dose increases and the turbidity of the gel increases, the radiation dose can be measured by measuring the turbidity of the gel.

By the way, the above-mentioned film dosimeter and polymer gel dosimeter are sheet-like dosimeters, and it is possible to see the irradiation state in a plane, but it is difficult to confirm the irradiation state in three dimensions. there were.
In the case of the polymer gel dosimeter, since it is a solid substance, it can be formed into a block having a certain size. However, when a dose distribution confirmation operation is performed using a polymer gel dosimeter formed in a block shape, there is a problem that the irradiation state inside the lesion is not visually recognized.
For example, it is assumed that a white turbid portion having a shape that substantially matches the outer shape of the lesion is obtained by the radiation therapy apparatus irradiating the block-shaped polymer gel dosimeter with the radiation in a state where the treatment plan is created. At this time, it can be seen from the shape of the cloudy portion that the irradiation state of the surface of the lesion is correct, but it is not known from the outer shape at all whether or not the radiation inside the lesion is uniformly irradiated. In other words, it was not visually confirmed whether or not the inside of the white turbid portion was uniformly clouded, and even if a polymer gel dosimeter was used, it was not easy to visually determine whether the treatment plan was correct.

  An object of the present invention is to provide a radiation irradiation range detector and a radiation irradiation range detection method capable of easily confirming a dose distribution before performing radiotherapy.

  The radiation irradiation range detector of the present invention includes a polymer gel sheet that changes from a transparent state to a cloudy state upon irradiation with radiation, a transparent holding member that is formed of a transparent resin and has a placement portion on which the polymer gel sheet is disposed, and transparent holding And a stacking mechanism for arranging the members in an overlapping manner.

  Further, in the radiation irradiation range detection method of the present invention, a polymer gel sheet that changes from a transparent state to a cloudy state by irradiation of radiation is disposed inside, is formed from a transparent resin, and is stacked on top and bottom. A plurality of radiation irradiation range detectors comprising a transparent holding member having Then, after irradiating the radiation with the plurality of radiation irradiation range detectors stacked on the stacking mechanism, the plurality of radiation irradiation range detectors were read and read by the scanner in a state of being separated one by one. The radiation irradiation state is detected from the cloudy state of each polymer gel sheet.

According to the present invention, since a plurality of transparent holding members on which polymer gel sheets are arranged are arranged in a stacked manner and irradiated with radiation, the irradiation state of the radiation can be confirmed three-dimensionally by changing the polymer gel sheet. Become. Therefore, for example, there is an effect that confirmation before performing radiotherapy can be easily performed.
In addition, since a plurality of radiation irradiation range detectors after radiation irradiation are separated and read by a scanner, a three-dimensional detection of the radiation irradiation state can be performed from the read image. The radiation irradiation state can be easily confirmed using a computer device.

It is a perspective view of the radiation irradiation range detector by the example of 1 embodiment of this invention. It is a disassembled perspective view of the radiation irradiation range detector by the example of 1 embodiment of this invention. It is a decomposition | disassembly side view of the radiation irradiation range detector by one embodiment of this invention. It is a side view of the radiation irradiation range detector by one embodiment of this invention. It is a side view which shows the lamination example of the radiation irradiation range detector by the example of 1 embodiment of this invention. It is explanatory drawing which shows the example of the detection process procedure by one embodiment of this invention. It is a side view which shows the example of the detection state by one embodiment of this invention. It is explanatory drawing which shows the example which takes in the detection image by one embodiment of this invention. It is a perspective view of the radiation irradiation range detector by the modification of one embodiment of this invention.

[1. Configuration example of radiation irradiation range detector]
Hereinafter, a radiation irradiation range detector according to an embodiment of the present invention (hereinafter referred to as “this example”) will be described with reference to the accompanying drawings.
FIG. 1 is a perspective view showing a radiation irradiation range detector 1 of this example, and FIG. 2 is an exploded perspective view. 3 is a side view of the radiation irradiation range detector 1 of this example in an exploded state, and FIG. 4 is a side view of the assembled state.
The radiation irradiation range detector 1 includes a thin rectangular transparent holding member 10 formed of a transparent resin. The transparent holding member 10 is made of a transparent resin such as an acrylic resin or a polycarbonate resin. As shown in FIG. 2, the transparent holding member 10 includes a polymer gel arrangement portion 11 on the upper side. A polymer gel sheet 20 is arranged in the polymer gel arrangement part 11.

The polymer gel sheet 20 is a sheet that is substantially transparent in a state where no radiation is irradiated, and is irradiated with radiation so that the irradiated portion becomes cloudy. That is, the polymer gel sheet 20 is a sheet in which a monomer is dispersed in a gel, and when irradiated with radiation, the monomer is polymerized to produce a polymer, thereby causing the gel to become clouded. This white turbidity makes it possible to visualize a region actually irradiated with radiation. The cloudiness state of the polymer gel sheet 20 changes substantially linearly in proportion to the radiation dose, and the cloudiness state becomes stronger as the radiation dose is higher. However, the correlation between the radiation dose and the cloudiness state changes depending on the composition of the polymer gel sheet 20, and the cloudiness state changes almost linearly as an example.
Here, the polymer gel sheet 20 is a relatively thin sheet having a thickness of about 1 mm to several mm. In addition, about the composition of the polymer gel sheet 20, it is disclosed by patent document 1 shown previously, for example. In addition to the composition disclosed in Patent Document 1 and the like, various compositions are known, and if the transparency changes like a cloudy state by irradiation of radiation, as the polymer gel sheet 20, Various compositions are applicable.

  The polymer gel placement portion 11 of the transparent holding member 10 has a shape that is recessed several millimeters from the upper end portion 12 corresponding to the thickness of the polymer gel sheet 20. In a state where the polymer gel sheet 20 is arranged in the polymer gel arrangement portion 11, the upper end portion 12 is covered with the transparent sheet 30, and the polymer gel sheet 20 is held in a sealed state. The transparent sheet 30 is fixed to the upper end portion 12 with an adhesive or the like.

On the upper surface side around the polymer gel placement portion 11 of the transparent holding member 10, a step portion 13 having a thin upper side wall is formed. Further, as shown in FIG. 3, a stacking recess 14 is formed on the lower surface side of the transparent holding member 10. The step portion 13 and the stacking concave portion 14 function as a stacking mechanism portion for stacking the plurality of transparent holding members 10 up and down.
That is, as shown in FIG. 3, when a plurality of transparent holding members 10 are prepared, the stepped portion 13 on the upper surface side of the transparent holding member 10 fits into the stacking concave portion 14 on the lower surface side of another transparent holding member 10. As a shape. In this stacked state, the upright surface 13a of the stepped portion 13 and the upright surface 14a of the stacking recess 14 are in contact with each other.

FIG. 5 shows an example of a state in which the radiation irradiation range detectors 1 are stacked.
In the example of FIG. 5, ten radiation irradiation range detectors 1 are prepared and stacked one above the other. Here, the transparent holding member 10 is stacked by fitting the step portion 13 on the upper surface side of each transparent holding member 10 into the stacking recess 14 on the lower surface side of another transparent holding member 10.
In the state where they are stacked as shown in FIG. 5, ten polymer gel sheets 20 arranged in each radiation irradiation range detector 1 are arranged in a stacked manner.

[2. Example of processing to detect radiation range]
FIG. 6 is a diagram illustrating a processing example for detecting a radiation irradiation range. Here, an example of performing dose distribution confirmation in a radiation irradiation state determined in a treatment plan when performing radiation therapy on a cancer patient will be described.

  First, as shown in FIG. 6A, a plurality of radiation irradiation range detectors 1 are prepared and stacked. At this time, each transparent holding member 10 is laminated by fitting the stepped portion 13 on the upper surface side into the stacking concave portion 14 on the lower surface side of another transparent holding member 10. The number of stacked radiation irradiation range detectors 1 depends on the height of the radiation irradiation range to be detected. For example, if the size of a lesion to be confirmed is about 5 cm in diameter, a plurality of radiation irradiation range detectors 1 are stacked so that the height is slightly larger than that. In the laminated radiation irradiation range detector 1, the transparent holding member 10 is transparent, and the polymer gel sheet 20 held inside is almost transparent, so that the inside can be seen through.

Next, the radiation treatment apparatus is used to irradiate the stacked radiation irradiation range detectors 1 in a radiation irradiation state determined in advance in a treatment plan. By irradiating with radiation, as shown in FIG. 6B, the polymer gel sheet 20 in the radiation irradiation range detector 1 becomes clouded at a location a where the radiation is strongly irradiated. If the prior treatment plan is appropriate, the shape of the cloudy portion a substantially matches the shape of the lesion that has been confirmed in advance.
Therefore, a doctor or engineer who performs radiation therapy can determine whether or not the prior treatment plan is appropriate by confirming the shape of the cloudiness point a by visual observation.

The shape of the cloudy spot a that can be visually confirmed in the stacked state shown in FIG. 6B is the outer shape of the cloudy spot a. And the judgment whether the radiation irradiation range inside the cloudy part a is appropriate is performed by separating the stacked radiation irradiation range detectors 1.
For example, as shown in FIG. 6C, a scanner 130 for reading an image is prepared. Then, the radiation irradiation range detectors 1 are arranged one by one on the reading table 131 of the scanner 130, and the scanner 130 reads the white turbid state of the polymer gel sheet 20 of the radiation irradiation range detector 1 as an image. The scanner 130 reads a plurality of radiation irradiation range detectors 1 at one time. This is one example, and the scanner 130 may read the radiation irradiation range detectors 1 one by one with the scanner 130 in order.

  6D, the image processing unit 110 in the computer apparatus 100 analyzes the image data read by the scanner 130 as a 3D image, and the analysis result is displayed on the display 120. For example, the cloudy part a is displayed three-dimensionally on the display 120 from various angles. Moreover, you may make it display the cloudiness state of the polymer gel sheet 20 of each radiation irradiation range detector 1 which the scanner 130 read as an image.

Further, the computer apparatus 100 compares the image of the lesion area of the patient obtained by using a CT scanner or an MRI apparatus with the image data read by the scanner 130, and determines whether or not the radiation irradiation range is appropriate. You may make it perform automatically.
Note that image analysis using the computer device 100 is one example. For example, as shown in FIG. 6C, the white turbid state of the polymer gel sheet 20 of the radiation irradiation range detector 1 separated one by one is determined by a doctor. Or an engineer may visually confirm whether or not the radiation irradiation state inside the lesion is appropriate.

Next, with reference to FIG. 7, a specific example in which a cloudy spot a occurs when radiation is irradiated using the radiation irradiation range detector 1 in a stacked state will be described.
The example of FIG. 7 shows a state in which ten radiation irradiation range detectors 1 are stacked. When radiation is radiated into the stacked radiation irradiation range detector 1, the irradiated portion becomes cloudy. Here, the polymer gel sheet 20 is arranged in a state where a gap is left for each sheet by the thickness held by the transparent holding member 10. Therefore, for example, as shown in FIG. 7, the white turbid portions a1 to a8 are divided into eight polymer gel sheets 20, and a slight transparent gap is generated in each of the white turbid portions a1 to a8. The gap is preferably as small as possible, for example, a thickness of 1 mm or less. However, such a gap has no problem in analyzing the radiation irradiation range.

FIG. 8 is an example in which a plurality of radiation irradiation range detectors 1 irradiated with radiation are shown separately.
As shown in FIG. 8, in the polymer gel sheet 20 of each radiation irradiation range detector 1, cloudy spots a1, a2, a3,... Showing the radiation irradiation range appear in a cross-sectional shape.
A doctor or engineer who performs radiation therapy looks at the cross-sectionally clouded points a1, a2, a3,... And sees whether the inside is uniformly clouded. Whether or not radiation has been irradiated to can be visually confirmed. If the cloudy spots a1, a2, a3,... Are not clouded or if they are cloudy but the cloudiness is less than the spot, the radiation It turns out that there is not enough irradiation.
Therefore, by using the radiation irradiation range detector 1 of this example, it can be easily seen visually whether or not the radiation treatment plan is appropriate.
Also, as shown in FIGS. 6C and 6D, a computer device 100 to which a scanner 130 is connected is prepared, and an image read by the computer device 100 is analyzed, so that the computer device 100 automatically performs a radiation treatment plan. It will be possible to judge the quality of.

[3. Modified example]
FIG. 9 shows an example of a radiation irradiation range detector 1 ′ having a cylindrical shape. In the radiation irradiation range detector 1 ′, the transparent holding member 10 has a cylindrical shape, and the polymer gel sheet 20 disposed on the transparent holding member 10 and the transparent sheet 30 with a lid on the upper end also have a circular shape. The stacking mechanism such as the step 13 around the transparent holding member 10 is also circular.
By making the radiation irradiation range detector 1 ′ cylindrical, it becomes easy to see the cloudiness of the polymer gel sheet 20 after radiation irradiation from any angle. In addition, when applied for confirmation when performing radiotherapy, the circular polymer gel sheet 20 is considered to have a shape close to the shape of the actual lesion, so that the radiation dose can be confirmed efficiently. . Note that the radiation irradiation range detector 1 ′ may have an elliptical shape corresponding to the part of the human body to be confirmed. For example, when the internal organ of the trunk is a lesion, the radiation irradiation range detector 1 ′ having various shapes and sizes such as an elliptical shape corresponding to the cross section of the trunk may be used.

In the above-described embodiment, the stacking mechanism provided in the transparent holding member 10 has a shape in which the step portion on the upper surface side and the recess portion on the lower surface side are fitted. On the other hand, a stacking mechanism having another shape may be used. In this case, the stacking mechanism portion may have an asymmetric shape on the left and right so that the left and right directions are determined when stacking, for example.
In the embodiment described above, the transparent sheet 30 is arranged on the polymer gel sheet 20 arranged in the polymer gel arrangement part 11 of the transparent holding member 10 so that the polymer gel sheet 20 is held in a sealed structure. I made it. On the other hand, for example, the transparent sheet 30 may be omitted. However, the radiation irradiation range detector 1 in which the transparent sheet 30 is disposed is superior in handling and the like, and the radiation irradiation range detector 1 preferably includes the transparent sheet 30.

  Furthermore, in the above-described embodiment, the radiation irradiation range detector 1 is used for confirming a treatment plan for radiation therapy. On the other hand, the radiation irradiation range detector 1 may be used for confirmation of other radiation irradiation states.

  DESCRIPTION OF SYMBOLS 1,1 '... Radiation irradiation range detector, 10 ... Transparent holding member, 11 ... Polymer gel arrangement | positioning part, 12 ... Upper end part, 13 ... Step part, 13a ... Upright surface, 14 ... Stacking recessed part, 14a ... Upright surface, DESCRIPTION OF SYMBOLS 20 ... Polymer gel sheet, 30 ... Transparent sheet, 100 ... Computer apparatus, 110 ... Image processing part, 120 ... Display, 121 ... Analysis image, 130 ... Scanner, 131 ... Reading stand

Claims (5)

A polymer gel sheet that changes from a transparent state to a cloudy state upon irradiation with radiation, and
A transparent holding member having an arrangement part in which the polymer gel sheet is arranged and molded from a transparent resin;
A radiation irradiation range detector comprising: a stacking mechanism for arranging transparent holding members in an overlapping manner. The radiation irradiation range detector according to claim 1, wherein the arrangement part of the transparent holding member on which the polymer gel sheet is arranged is covered with a transparent sheet. The stacking mechanism portion includes a stepped portion provided on one of the upper and lower surfaces of the transparent holding member, and a concave portion provided on the other surface and having a shape corresponding to the stepped portion. Or the radiation irradiation range detector of 2. The polymer gel sheet has a circular shape,
The radiation irradiation range detector according to any one of claims 1 to 3, wherein the circular polymer gel sheet is also arranged in the arrangement portion of the transparent holding member. Radiation irradiation range detector comprising a transparent holding member having a stacking mechanism for arranging a polymer gel sheet that changes from a transparent state to a cloudy state by irradiation with radiation, formed from a transparent resin, and stacked vertically Prepare several,
In a state where the plurality of radiation irradiation range detectors are overlapped with the stacking mechanism unit, after irradiating radiation,
In a state where the plurality of radiation irradiation range detectors are separated for each one, read by a scanner,
A radiation irradiation range detection method, wherein the read cloudy state of each polymer gel sheet is subjected to image processing to detect a radiation irradiation state.

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