JPH0712940A - Radiation detector and radiation dose evaluation method - Google Patents

Abstract

PURPOSE:To obtain a radiation detector the shape of which can be changed in accordance with an object to be measured and which does not require any special external equipment for the evaluation of radiation doses by providing solid bodies which can sense radiations and have a fixed shape and a plastic sheet-like fixture which scatteredly supports the solid bodies. CONSTITUTION:A sheet 13 is made of a easily cuttable material, such as the plastic rubber, plastics, etc., and projections are planted on the surface of the sheet 13 at regular intervals L. Solid bodies 14 which have appropriate shapes due to their flexible structures and can sense radiations are fixed on the surface of the sheet 13 by press- fitting the solid bodies 14 among the projections. The solid bodies 14 are made of, for example, an alkali halide, such as LiF, NaC, etc., and the diameters D of the bodies 14 are at the level of millimeters in maximum. The intervals L of the projections on the sheet 13 are changed depending upon the state of radiations. The sensitivity of the sheet 13 can be freely set by changing the intervals L of the projections and diameters Dof the solid bodies 14. In addition, when the solid bodies 14 are fixed in an area irradiated with radiations, the exposure dose can be recognized, because the color or color density of the solid bodies 14 changes due to their radiation physical properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detection apparatus for industrial and medical equipment using radiation and a method for evaluating radiation dose.

[0002]

2. Description of the Related Art A conventional radiation detecting apparatus will be described with reference to FIGS. 6, 7 and 8. FIG. 6 is a view showing an ionization chamber type dosimeter which is one of conventional radiation detecting devices. Further, FIG. 7 is a diagram showing a Loritzen voltage detector which is one of conventional radiation detecting devices. Furthermore, FIG.
FIG. 4 is a diagram showing a film badge which is one of conventional radiation detection devices.

FIG. 6 shows the principle of an ionization chamber type dosimeter,
(A) shows an electric current method and (b) shows an electrostatic method. In the figure, 1 is a box for enclosing an ionized gas, 2 is an electrode for collecting charges (cations, electrons) generated in the box 1 by ionization, and 3 is an electrode for collecting a charge on the electrode 2. The voltage sources 4 are electrometers for evaluating the amount of collected electric charges.

7A and 7B show the principle of the Loritzen voltage detector. FIG. 7A is an overall side view, FIG. 7B is a partial view of a pointer described later, and FIG. 7C is a view seen from a microscope described later. In the figure, 5 is a box for enclosing ionized gas, 6 is an electrometer that also functions as a pointer that moves in proportion to the amount of collected electric charge, 7 is an insulator for insulating the pointer 6 from the box 5, and 8 is It is a microscope with a scale for measuring the amount of movement of the pointer 6.

FIG. 8 shows the principle of a film badge,
(A) shows the front and (b) shows the side. In the figure, 9 is a film, 10 is a box for storing the film 9, for example, a plastic box, 11 and 12 are the film 9 and the box 1.
It is a filter of lead, copper, aluminum, etc. that adjusts (shields) the radiation sensitivity by sandwiching it between zero.

[0006]

In the conventional radiation detecting apparatus as described above, the box 1 for enclosing the ionized gas,
5 is required, there is a problem that it is difficult to process the object to be measured according to its shape.

There is also a problem that a special device such as a voltage source 3, an electrometer 4 and a developing device for the film 9 is required to evaluate the detected radiation dose.

The present invention has been made in order to solve the above-mentioned problems, and can process the shape according to the object to be measured and does not require a special external device for evaluating the radiation dose. The purpose is to obtain a method for evaluating quantity.

[0009]

A radiation detecting apparatus according to claim 1 of the present invention comprises the following means. [1] A solid with a certain shape that is sensitive to radiation. [2] A sheet-shaped plastic fixture that supports a plurality of the solids by distributing them according to the radiation environment.

The radiation dose evaluation method according to claim 2 of the present invention includes the following steps. [1] Processing a radiation detection device having a solid shape sensitive to radiation and a sheet-shaped plastic fixture that distributes and supports a plurality of solids according to the radiation environment in accordance with the shape of the object to be measured Steps to take. [2] A step of arranging the processed radiation detection device on the back side of the object to be measured and evaluating the amount of irradiated radiation by the change in the color of the solid.

[0011]

In the radiation detecting apparatus according to the first aspect of the present invention, the irradiated radiation is absorbed by the solid having a certain shape sensitive to the radiation, and the color of the solid is changed according to the amount thereof. Moreover, the sensitivity can be adjusted according to the radiation environment by a sheet-shaped plastic fixture that supports a plurality of the above-mentioned solids by being distributed according to the radiation environment, and can be processed according to the shape of the object to be measured.

In the method for evaluating a radiation dose according to claim 2 of the present invention, a solid sheet having a certain shape sensitive to radiation and a plurality of the solid sheets distributed and supported according to a radiation environment are supported by the first step. A radiation detection device having a plastic fixing tool is processed according to the shape of the object to be measured. Further, in the next step, the processed radiation detecting device is arranged on the back side of the object to be measured, and the dose of irradiation is evaluated by the change in color of the solid.

[0013]

【Example】

Example 1. The configuration of the first embodiment of the radiation detecting apparatus according to the present invention will be described with reference to FIG. 1A and 1B are views showing a configuration of a first embodiment of the present invention, in which FIG. 1A is a front view and FIG. 1B is a side view.

In the figure, reference numeral 13 is a sheet which can be cut by a simple method, for example, a sheet of plastic (rubber, plastic, etc.) whose surface is provided with projections at regular intervals L. Further, 14 is a radiation-sensitive solid such as an alkali halide (LiF: lithium fluoride, NaCl: salt, etc.). Since the sheet 13 has a flexible structure, it is fixed by pressing a radiation-sensitive solid 14 having an appropriate shape into the space between the protrusions. The diameter D of the radiation-sensitive solid 14
Is large and on the order of mm.

By the way, the solid body having a fixed shape according to claim 1 of the present invention is the radiation-sensitive solid body 14 in the first embodiment.
And the plastic fixture according to claim 1 of the present invention is
In this Embodiment 1, it corresponds to the sheet 13.

Next, the operation of the above-described first embodiment will be described. The distance L between the protrusions of the sheet 13 is changed depending on the radiation environment applied. That is, in an environment where the radiation dose density is high, the interval L between the protrusions is increased, and the number of radiation-sensitive solids 14 per unit density is reduced. Further, the diameter D of the radiation-sensitive solid 14 is increased so that the dose absorbed by the radiation-sensitive solid 14 per unit irradiation dose becomes low. In this way, the sensitivity to radiation is low.

On the contrary, in an environment where the radiation dose density is low,
The interval L between the protrusions is reduced, and the number of radiation-sensitive solids 14 per unit density is increased. Also, radiation sensitive solid 1
The diameter D of 4 is made small so that the dose absorbed by the radiation-sensitive solid 14 per unit irradiation dose becomes high. In this way, it is made highly sensitive to radiation.

As described above, the radiation detecting apparatus according to the first embodiment is obtained by cutting the sheet 13 shown in FIG. 1 into a desired shape (object to be measured). Further, the sensitivity to radiation can be freely set by the distance L between the protrusions of the sheet 13 and the diameter D of the radiation-sensitive solid 14.

Further, the radiation-sensitive solid 14 fixed to the area irradiated with the radiation makes it possible to know the irradiation dose from the change in color or color density according to the radiation physical properties of the solid. For example, the alkali halide lithium fluoride (LiF) changes from transparent to yellow upon irradiation with radiation. The radiation dose can be evaluated from the degree of this color change.

Example 2. Example 2 of the radiation dose evaluation method according to the present invention will be described below. The case of using for confirming the X-ray irradiation field of the X-ray generator or estimating the approximate value of the irradiation dose when taking an industrial X-ray radiograph will be described with reference to FIGS. 2 and 3. Figure 2
It is a figure which shows the state which cut | disconnected the sheet | seat which concerns on Example 2 of this invention in circular shape. Further, FIG. 3 is a diagram showing a usage state of the circular sheet shown in FIG.

In FIG. 2, 13A is a sheet obtained by cutting the sheet 13 shown in FIG. 1 into an appropriate circular shape. Reference numeral 15 is a holder for fixing the sheet 13A with, for example, double-sided tape.

In FIG. 3, 16 is an X-ray generator, 17
Is an object (measurement object) of an X-ray transmission photograph. Before taking an X-ray transmission photograph, a holder 15 with a sheet 13A fixed is arranged in front of the original film for photographing, and the irradiation field or the shape of the area appearing on the sheet 13A in which the color or the color density is changed, or The irradiation dose can be known.

The radiation dose evaluation method according to the second embodiment makes it possible to simplify the test photographing before the industrial X-ray radiography.

Example 3. A third embodiment of the radiation dose evaluation method according to the present invention will be described below. A case in which the medical tumor treatment apparatus is used for confirming a radiation irradiation field or estimating an approximate value of irradiation dose during irradiation of a patient will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram showing a state in which a sheet according to the third embodiment of the present invention is cut into a rectangle. Further, FIG. 5 is a diagram showing a usage state of the rectangular sheet shown in FIG.

In FIG. 4, 13B is obtained by cutting the sheet 13 shown in FIG. 1 into a rectangular shape. Also, 1
5A is a holder for fixing the sheet 13B with, for example, double-sided tape.

In FIG. 5, reference numeral 18 is a medical tumor treatment apparatus, and 19 is a fixed base for a patient. Holder 1 with sheet 13B fixed to the underside of a patient (not shown) prior to patient irradiation
By arranging 5A, it is possible to know the irradiation field or irradiation dose from the shape of the region where the color or the color density appears on the sheet 13B.

With the radiation dose evaluation method according to the third embodiment, it is possible to simplify the confirmation of the radiation irradiation field or the estimation of the approximate value of the irradiation dose when irradiating the patient with the medical tumor treatment apparatus. .

Originally, when a structural material or a material in a portion which is not premised to be irradiated with the radiation by the radiation generating apparatus is irradiated with the radiation, those materials are activated and a person who works around the apparatus operates. Alternatively, the article may be exposed to radiation from the activated material. In the past, it was difficult to take out a part of the components, materials, etc. of the device and measure the degree of activation of only that part with a conventional radiation detection device.

Therefore, the radiation detecting apparatus according to the first embodiment does not use a special radiation evaluating apparatus, but uses a sheet 13 to which a solid radiation sensitive material 14 on which a radiation exposure amount can be visually confirmed by color or density is fixed. Processing (cutting, etc.) is performed in accordance with the shape of the part that is previously irradiated with radiation and is expected to be activated, or the part that is activated by unexpected radiation. This is used as a radiation detection device. In addition, the radiation dose evaluation method according to the second and third embodiments is a method of evaluating the irradiation dose of a specified portion in a device using radiation using the radiation detection device.

That is, in the radiation detecting apparatus according to the first embodiment, the radiation-sensitive solid 14 of which the color or the density of the color changes by absorbing the radiation is processed into a fixed shape having an appropriate size. The one that is used is used. The solid 14 processed in this way is attached to the sheet 13 that can be cut by a simple method.

In the second and third embodiments, the sheet 13 that can be cut by a simple method is cut according to the shape of the object to be measured, and the radiation-sensitive solids 14 are scattered and fixed to fix the radiation. The shape of the device can be formed as it is.

The sensitivity to radiation is solved by changing the number of the radiation-sensitive solids 14 per unit area, that is, the degree of scattering, in the arrangement of the fixing portion of the radiation-sensitive solids 14 of the sheet 13.

[0033]

As described above, the radiation detecting apparatus according to the first aspect of the present invention is a sheet that supports a solid having a certain shape sensitive to radiation and a plurality of the solids distributed according to the radiation environment. Since it is provided with the plastic fixing tool, it is possible to broaden the applicable radiation environment.

As described above, the method for evaluating a radiation dose according to the second aspect of the present invention is a sheet-like body that supports a solid having a certain shape sensitive to radiation and a plurality of the solids distributed according to the radiation environment. A step of processing a radiation detection device having a plastic fixture according to the shape of the object to be measured, and the processed radiation detection device is arranged on the back side of the object to be measured, and the radiation dose irradiated is the color of the solid. And the step of evaluating the radiation environment by changing the value of (1), there is an effect that the applicable radiation environment can be widened.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a radiation detecting apparatus according to the present invention.

FIG. 2 is a second embodiment of the radiation dose evaluation method according to the present invention.
It is a figure which shows the radiation detection apparatus used for.

FIG. 3 is a diagram showing a usage state of Embodiment 2 of the present invention.

FIG. 4 is a third embodiment of the radiation dose evaluation method according to the present invention.
It is a figure which shows the radiation detection apparatus used for.

FIG. 5 is a diagram showing a usage state of Embodiment 3 of the present invention.

FIG. 6 is a view showing an ionization chamber type dosimeter which is one of conventional radiation detection devices.

FIG. 7 is a diagram showing a Loritzen voltage detector which is one of conventional radiation detection devices.

FIG. 8 is a view showing a film badge which is one of conventional radiation detection devices.

[Explanation of symbols]

 13 Sheet with Implanted Protrusions at a Constant Interval 13A Sheet Cut into Circle 13B Sheet Cut into Rectangle 14 Radiation Sensitive Solid 15 Holder 15A Holder 16 X-ray Generator 17 Object of X-ray Radiograph 18 Medical Tumor Treatment Device 19 Patient support

Claims (2)

[Claims] 1. A radiation detecting apparatus comprising: a solid body having a fixed shape sensitive to radiation; and a sheet-shaped plastic fixture that distributes and supports a plurality of solid bodies according to a radiation environment. 2. A radiation detection device having a radiation-sensitive solid having a fixed shape and a sheet-shaped plastic fixture for supporting a plurality of the solids distributed in accordance with the radiation environment. And a step of arranging the processed radiation detection device on the back side of the object to be measured, and evaluating the irradiated radiation quantity by a change in the color of the solid. .