JP2004129678A - Water phantom device for imrt measurement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water phantom device which can effectively implement an IMRT therapy. <P>SOLUTION: This water phantom device for IMRT (intensity modulated radiotherapy) measurement is provided with a water tank (12) which has a tank body part (14) filled with water and extended horizontally and an inlet part (16) which communicates with the tank body part with a fluid and has the upper end thereof extended vertically above the uppermost part of the tank body part. A sensor (18) is arranged in the tank body part to measure a radiation dose irradiated and a positioning means (20) for positioning the sensor at a desired point within the body tank part, is further provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention generally relates to a water phantom device for measuring intensity modulated radiotherapy (IMRT). More specifically, the present invention relates to a water phantom device that can effectively perform IMRT treatment. Here, the phantom is a model used in place of the human body to determine the radiation dose to the internal organs of the human body.
[0002]
[Prior art]
In recent years, IMRT has been in the spotlight in the field of radiation therapy. Unlike conventional three-dimensional conformal irradiation, in which it is difficult to irradiate a tumor with sufficient dose while avoiding irradiation of surrounding organs, IMRT is minimizing irradiation of normal tissues surrounding the tumor. Irradiation on the irradiation surface can be made more or less intense, so that a sufficient dose can be applied to the tumor. In IMRT, in order to perform high-precision irradiation, a detailed treatment plan is created before a patient is actually subjected to radiation treatment, and a simulation irradiation test is performed using a simulator to check the irradiation dose and other information. Need to be implemented. As such a simulator, a phantom imitating a human body (for example, a plastic phantom made of plastic, a water phantom filled with water, or the like) is known.
[0003]
[Problems to be solved by the invention]
However, with a plastic phantom, since the phantom is a solid, it is difficult to arrange a sensor at an arbitrary position in the phantom, so that it has been difficult to perform a highly accurate checking operation. Further, in the conventional water phantom, it is difficult to completely fill the inside of the phantom with water, and it is also difficult to perform a highly accurate checking operation. Therefore, there has been a strong demand for a phantom device that can perform a high-accuracy simulation test.
[0004]
The present invention has been devised in view of such circumstances, and has as its object to provide a water phantom device capable of effectively performing IMRT treatment.
[0005]
[Means for Solving the Problems]
The water phantom device for IMRT measurement according to claim 1 of the present application includes a water tank, wherein the water tank is provided with a horizontally extending main body portion that is filled with water, and is in fluid communication with the main body portion. Having an inlet portion extending vertically above the top, disposed in the body portion, a sensor for measuring the amount of irradiated radiation, and the sensor at a desired location in the body portion. And positioning means for positioning.
[0006]
A water phantom device for IMRT measurement according to a second aspect of the present invention is the water phantom device for an IMRT measurement according to the first aspect, wherein the main body portion has a cylindrical shape, and the entrance portion has a rectangular parallelepiped shape.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings. A water phantom device for IMRT measurement according to a preferred embodiment of the present invention, generally indicated by reference numeral 10 in FIG. 1, includes a water tank 12 filled with water. The water tank 12 has a cylindrical main body portion 14 extending in the horizontal direction, and one end of the main body portion 14 is closed by a wall 14a. On the lower surface of the main body portion 14, legs 14b are attached so that the water tank 12 can be placed on a flat base. The direction in which the main body portion 14 extends is referred to as an X direction, a horizontal direction perpendicular to the X direction is referred to as a Y direction, and a vertical direction perpendicular to the X direction is referred to as a Z direction.
[0008]
The aquarium 12 also has an inlet portion 16 connected to the other end of the body portion 14, the inlet portion 16 having a rectangular parallelepiped having an upper end 16a extending vertically above the uppermost portion 14c of the body portion 14. It has a shape. The body portion 14 and the inlet portion 16 are in fluid communication, and the upper end 16a of the inlet portion 16 is open. The water tank 12 is preferably formed of a suitable material such as a transparent acrylic resin material.
[0009]
With the configuration of the water tank 12 as described above, when water is injected into the water tank 12 from the inlet portion 16 so that the water surface is located above the uppermost portion 14c of the main body portion 14 as shown in FIG. The body portion 14 will be filled with water.
[0010]
The water phantom device for IMRT measurement 10 is also provided in the water tank 12 and includes a sensor 18 for measuring the amount of irradiated radiation, that is, a micro chamber (miniature ionization chamber).
[0011]
The water phantom device 10 for IMRT measurement further includes a positioning means 20 for positioning the sensor 18 at a desired position in the main body portion 14 of the water tank 12. The positioning means 20 has a first base 22 placed on a base. A concave portion 22a is formed on the upper surface of the first base 22, and a pair of opposed grooves 22b are provided extending along both edges of the concave portion 22a in the Y direction (a direction perpendicular to the plane of FIG. 1). I have.
[0012]
The positioning means 20 also has a second base 26 arranged so as to be slidable in the Y direction in the recess 22a of the first base 22. That is, a projection 26 b having a shape corresponding to the groove 22 b of the first base 22 is provided at both edges of the second base 26, and the projection 26 b is formed by the groove 22 b of the first base 22. It is arranged to fit into.
[0013]
On one side of the first base 22, a Y-direction moving mechanism 24 (not shown in FIG. 7 for simplification of the drawing) for moving the second base 26 in the Y direction is provided. The Y-direction moving mechanism 24 has a rotatable shaft 24a extending in the vertical direction, and a helical gear 24b provided below the shaft 24a is provided on a corresponding side of the second base 26. The rack (gear) 26c (see FIGS. 5 and 7) is engaged with the rack 26c. With this configuration, when the shaft 24a of the Y-direction moving mechanism 24 is rotated, the second base 26 slides in the Y direction.
[0014]
The positioning means 20 also has a third base 30 arranged so as to be slidable in the X direction within the recess 26a of the second base 26. That is, on both edges of the third base 30, projections 30a having a shape corresponding to a pair of opposed grooves 26d extending in the X direction along both edges of the concave portion 26a of the second base 26 are provided, The third base 30 is arranged so that the projection 30a is fitted into the groove 26d of the second base 26.
[0015]
An X-direction moving mechanism 28 (see FIG. 6, not shown in FIG. 7 for simplifying the drawing) for moving the second base 26 in the X direction is provided on one side of the second base 26. ing. The X-direction moving mechanism 28 has a rotatable shaft 28a extending in the vertical direction, and a helical gear 28b provided at a lower portion of the shaft 28a is provided on a corresponding side of the third base 30. The rack (gear) 30b (see FIGS. 6 and 7) meshes with the rack 30g. With this configuration, when the shaft 28a of the X-direction moving mechanism 28 is rotated, the third base 30 slides in the X direction.
[0016]
The positioning means 20 further has a Z-direction moving mechanism 32 arranged on the third base 30. The Z-direction moving mechanism 32 is screwed into a tripod portion 32a fixed on the third base 30, a base portion 32b located at the top of the tripod portion 32a, and an opening (not shown) provided at the center of the base portion 32b. A shaft 32c with a male thread, a gear (not shown) arranged in the base 32b so as to mesh with the shaft 32c with a male thread, and a handle 32d for rotating the gear arranged in the base 32b. I have. By rotating the handle 32d, the externally threaded shaft 32c moves in the vertical direction (Z direction).
[0017]
An arm 34 for mounting the sensor 18 is fixed to the upper end of the male threaded shaft 32c of the Z-direction moving mechanism 32. The arm 34, as best shown in FIG. 1, includes a first portion 34a extending horizontally from the upper end of the externally threaded shaft 32c, and a second portion 34b extending vertically downward from the tip of the first portion 34a. And a third portion 34c extending in the horizontal direction from the tip of the second portion 34b to the opposite side to the first portion 34a, and the sensor 18 is attached to the tip of the third portion 34c.
[0018]
The use of the water phantom device 10 for IMRT measurement configured as described above will be described. First, a CT image of a patient to be treated is taken, and a treatment plan (for example, data such as radiation dose, irradiation direction, and irradiation time) is created. Next, a CT image of the water phantom device 10 in which the main body portion 14 of the water tank 12 is completely filled with water is taken. At this time, the sensor 18 is moved to a location to be irradiated (that is, a location corresponding to the affected part of the patient). Then, irradiation is performed from all directions, the irradiation value predicted in the treatment plan is compared with the irradiation value actually measured by the sensor 18, and the validity of the predicted value is verified.
[0019]
The present invention is not limited to the above embodiments of the invention, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the invention. Needless to say, it is.
[0020]
For example, in the above-described embodiment, the water tank 12 is configured by the cylindrical main body portion 14 and the rectangular parallelepiped entrance portion 16, but for example, the main body portion may be a rectangular parallelepiped (FIG. 8A). (See FIG. 8 (b)), or the inlet portion may be cylindrical (see FIG. 8 (c)).
[0021]
The positioning means 20 includes a first base 22, a second base 26, a third base 30, a Y-direction movement mechanism 24, an X-direction movement mechanism 28, and a Z-direction movement mechanism 32. Other configurations may be used as long as they can be positioned at any three-dimensional (ie, X, Y, and Z directions) positions.
[0022]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, since the inside of the main body part of an aquarium can be completely filled with water and a sensor can be located in any desired location in a main body part, it can implement IMRT treatment effectively. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a water phantom device according to a preferred embodiment of the present invention.
FIG. 2 is a side view of a water tank of the water phantom device of FIG.
FIG. 3 is a plan view of a water tank of the water phantom device of FIG.
FIG. 4 is an enlarged front view of a positioning means of the water phantom device of FIG.
5 (a) is an enlarged view of a Y-direction moving mechanism of a positioning means, and FIG. 5 (b) is a view as seen from line 5b-5b in FIG. 5 (a).
FIG. 6 is a view from line 6-6 in FIG. 4;
FIG. 7 is an enlarged exploded perspective view of the positioning means.
FIG. 8 is a schematic perspective view showing a modified form of the water tank.
[Explanation of symbols]
Reference Signs List 10 Water phantom device for IMRT measurement 12 Water tank 14 Body portion 16 Inlet portion 18 Sensor 20 Positioning means

Claims (2)

A water phantom device for IMRT measurement,
A water tank, wherein the water tank has a horizontally extending body portion filled with water, an inlet portion in fluid communication with the body portion, and an upper end vertically extending above the top of the body portion. Has,
The apparatus further comprising a sensor disposed in the main body portion for measuring an emitted radiation dose, and positioning means for positioning the sensor at a desired position in the main body portion. . The device of claim 1, wherein the body portion is cylindrical and the inlet portion is rectangular.

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