Transformation device for transforming a treatment beam for treating a lesion in a target body

Abstract

The present invention relates to a conversion device that converts a treatment beam for treating a lesion in a target body, and includes a collimator section into which the treatment beam is incident and in which a plurality of slits are formed, and a scattering section that scatters the treatment beam that has passed through the collimator section.

Description

[Technical field]

[0001] The present invention relates to a transformation device for transforming a treatment beam for treating a lesion in a subject. [Background technology]

[0002] Charged particle beams, such as proton beams, are used to treat lesions such as brain tumors.

[0003] During the treatment, a large amount of radiation may be irradiated to normal tissues of the patient located in the path of the proton beam, causing problems that may affect the normal tissues. For example, during proton beam treatment of a brain tumor patient, the proton beam may cause hair loss.

[0004] Hair loss has a very negative impact on school and social life, particularly for pediatric brain tumor patients and female patients, and is a problem that significantly reduces the quality of life. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS It is therefore an object of the present invention to provide a treatment beam conversion device that reduces the effects on normal tissue located along the path of the beam during a charged particle beam, such as a proton beam, treatment process. [Means for solving the problem]

[0006] The object of the present invention is achieved by a conversion device that converts a treatment beam for treating a lesion in a target body, comprising a collimator section into which the treatment beam is incident and in which a plurality of slits are formed, and a scattering section that scatters the treatment beam that has passed through the collimator section.

[0007] The treatment beam may include a charged particle beam.

[0008] The charged particle beam may include one of a proton beam, a helium ion beam, and a carbon ion beam.

[0009] Each of the slits may be elongated, the plurality of slits may be formed side by side, and the treatment beam may be spatially divided by the slits.

[0010] The treatment beam may be incident on the plurality of slits at different incident angles, and the extension direction of each slit may be formed to correspond to the corresponding incident angle.

[0011] The extension length of the shortest slit among the plurality of slits in the direction of travel of the treatment beam may be 1.5 to 10 times the maximum penetration depth of the treatment beam.

[0012] The collimator section may include a first collimator section and a second collimator section arranged along a traveling direction of the treatment beam.

[0013] The collimator portion may be formed to include one of brass and tungsten.

[0014] The collimator portion may be recessed toward the lesion.

[0015] The scattering portion may be provided in a plurality of portions each having a different scattering degree and selected by a user.

[0016] The scattering section may include a first scattering section and a second scattering section located between the first scattering section and the lesion, and the first scattering section and the second scattering section may each include a plurality of scattering sections having different degrees of scattering.

[0017] The treatment beam that has passed through the scattering section is irradiated onto the lesion, and the treatment beam can be switched to an unsplit state at the lesion.

[0018] The scattering portion may include a metal plate.

[0019] The metal of the metal plate has a density of 10 g / cm 3 or 25g / cm 3 may be also possible.

[0020] The metal of the metal plate may include any one of lead, bismuth, and tungsten.

[0021] The treatment beam is converted into spatially divided therapeutic radiation while passing through the collimator and the scattering section, and may further include an absorbing section located between the scattering section and the lesion and absorbing at least a portion of the radiation.

[0022] The absorbent portion has a density of 0.7 g / cm 3 or 2g / cm 3 The polymer has a density of 2 g / cm 3 or 6g / cm 3 The metal oxide may be formed by including any one of the metals listed below.

[0023] The total thickness of the air layer between the collimator section and the absorber section is adjustable and may be between 1 cm and 8 cm.

[0024] The spacing between the absorbent and the lesion may be adjustable.

[0025] The imaging device may further include a detachable range shifter disposed between a treatment beam delivery device for delivering the treatment beam and the collimator unit, the range shifter shifting a penetration depth of the treatment beam in the target body to a shallower depth.

[0026] The object of the present invention can be achieved by providing a conversion device that converts a treatment beam for treating a lesion in a target body, the conversion device including a collimator section that increases the PVDR of the incident treatment beam and switches it from a non-split state to a spatially split state, and a scattering section that scatters the treatment beam that has passed through the collimator section.

[0027] A plurality of slits are formed in the collimator section, and the PVDR of the treatment beam passing through the collimator section can be monotonically decreased according to the penetration depth.

[0028] The treatment beam that has passed through the scattering portion can be irradiated to the lesion with a PVDR reduced to 1.0 to 1.2. Effect of the Invention

[0029] According to the present invention, a treatment beam conversion device is provided that reduces the effects on normal tissue during a treatment process using a charged particle beam such as a proton beam. [Brief description of the drawings]

[0030] [Figure 1a] FIG. 1 is a diagram showing a usage pattern of a conversion device according to a first embodiment of the present invention. [Figure 1b] FIG. 1 is a diagram showing a usage pattern of a conversion device according to a first embodiment of the present invention. [Figure 1c] FIG. 1 is a diagram showing a usage pattern of a conversion device according to a first embodiment of the present invention. [Diagram 2] 1 is a diagram showing a configuration of a conversion device according to a first embodiment of the present invention. [Diagram 3] 3 is a diagram showing a change in dose profile of a proton beam in the conversion device according to the first embodiment of the present invention. FIG. [Figure 4] 5A and 5B are diagrams for explaining a change in the penetration depth of a proton beam due to a range shifter in the conversion device according to the first embodiment of the present invention. [Diagram 5] 1 is a diagram showing a cross section of a collimator portion in a conversion device according to a first embodiment of the present invention. [Figure 6] This is a simulation of the side dose distribution depending on the beam incidence angle and the slit extension direction. [Figure 7] 13 is a simulation result showing the change in PVDR depending on the depth of the medium when the thickness of the collimator part is changed. [Figure 8]This is a simulation result showing the change in PVDR depending on the depth of the medium when the thickness of the metal plate in the scattering part is changed. [Figure 9] 4 is a diagram showing the thickness of an air layer between a collimator section and an absorber section in the conversion device according to the first embodiment of the present invention. FIG. [Figure 10] FIG. 11 is a cross-sectional view of a collimator portion in a conversion device according to a second embodiment of the present invention. [Figure 11] 13 is a diagram showing a form of a collimator section in a conversion device according to a third embodiment of the present invention. FIG. [Figure 12] 13A and 13B are diagrams showing the shape of a scattering portion in a conversion device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will now be described in more detail with reference to the drawings.

[0032] The accompanying drawings are merely examples shown to more specifically explain the technical ideas of the present invention, and the ideas of the present invention are not limited to the accompanying drawings. In the accompanying drawings, thicknesses and lengths of each part may be exaggerated for the sake of explanation.

[0033] In the following embodiment, a proton beam is exemplified as a treatment beam, but the treatment beam of the present invention may be one of charged particle beams. The charged particle beam may be any one of a proton beam, a helium ion beam, and a carbon ion beam.

[0034] In the following examples, a tumor located in the brain will be described as an example of a lesion to be treated; however, the location and type of the lesion to be treated in the present invention are not limited thereto.

[0035] 1a, 1b and 1c are diagrams showing a usage form of a conversion device according to a first embodiment of the present invention.

[0036] The converter 1 is used by being connected to the end of a proton beam delivery device that delivers the generated proton beam to a patient.

[0037] The proton beam delivery device is connected to a gantry and rotated. The patient (subject) lies on a bed located in the extension of the proton beam delivery device, and the proton beam is irradiated to the patient's lesion after passing through a conversion device.

[0038] The specific shape of the proton beam delivery device may be changed depending on the location of the lesion, and the patient's position during treatment may also be changed.

[0039] As shown in FIG. 2, the conversion device 1 includes a range shifter 10, a collimator section 20, a scattering section 30, an absorption section 40, and a selection section 50.

[0040] In FIG. 2, illustration of a case configuration that houses each component, a configuration that supports each component within the case, a configuration that adjusts the selection unit 50 from the outside, a configuration that adjusts the distance between each component, and the like is omitted.

[0041] In addition, in FIG. 2, a configuration for coupling the conversion device 1 to a proton beam delivery device is not shown, and the coupling configuration may be appropriately selected by those skilled in the art.

[0042] The range shifter 10, the collimator section 20, the scattering section 30 and the absorption section 40 are sequentially arranged between the proton beam transmission device and the lesion, and the proton beam is irradiated to the lesion after passing through the range shifter 10, the collimator section 20, the scattering section 30 and the absorption section 40 in sequence.

[0043] The proton beam that has passed through the converter 1 passes through the patient's scalp, skull, and normal brain, and is then irradiated onto the tumor, which is the lesion to be treated.

[0044] The dose profile of the proton beam is shown in Figure 3, sequentially from the patient's scalp to the tumor.

[0045] The proton beam irradiated to the scalp, which should be protected from the proton beam, is spatially divided, and the PVDR (peak-valley dose ratio) is high. PVDR can be calculated as Dp (peak dose) / Dv (valley dose).

[0046] In the present invention, "spatial division" means that a spatially periodic dose distribution is formed. The spatial division can be considered as a state in which the PVDR of the proton beam is 1.1 or more, 1.2 or more, or 1.5 or more, and can be substantially 1.1 to 200, 1.2 to 200, or 1.5 to 200.

[0047] The PVDR of a proton beam incident on the scalp can be from 3.0 to 100.

[0048] As the spatially fractionated proton beam passes through the scalp, skull and normal brain, low-dose regions are formed along the beam path, sparing normal tissue, particularly reducing hair loss.

[0049] Then, when the proton beam reaches the lesion to be treated, the spatial division of the beam is switched to an undivided state, the low-dose region disappears, and the PVDR approaches 1. The uniform dose is used to effectively treat the lesion. The PVDR of the proton beam irradiated to the lesion can be 1.0 to 1.1 or 1.0 to 1.2.

[0050] As described above, the present invention maintains high spatial resolution in normal tissues and achieves non-resolution in tumors, thereby maximizing protection of normal tissues and effectively treating tumors.

[0051] In the following, the conversion device according to the present invention will be described in detail with reference to FIGS.

[0052] FIG. 4 is a diagram for explaining the change in penetration depth of a proton beam due to a range shifter in a conversion device according to the first embodiment of the present invention, FIG. 5 is a diagram showing a cross section of the collimator section in a conversion device according to the first embodiment of the present invention, FIG. 6 is a simulation of the side dose distribution depending on the beam incidence angle-slit extension direction, FIG. 7 is a simulation result showing the change in PVDR depending on the depth of the medium when the thickness of the collimator section is different, FIG. 8 is a simulation result showing the change in PVDR depending on the depth of the medium when the thickness of the metal plate of the scattering section is different, and FIG. 9 is a diagram showing the thickness of the air layer between the collimator section and the absorbing section in a conversion device according to the first embodiment of the present invention.

[0053] The range shifter 10 is located between the proton beam delivery device and the collimator section 20. The range shifter 10 changes the penetration depth of the proton beam in the target body, and in particular, moves the penetration depth of the proton beam into the patient to a shallower depth as shown in FIG. 4. The range shifter 10 has a density of 0.7 g / cm 3 or 2g / cm 3 The range shifter 10 may be made of a polymer material and may be in the form of a plate having a uniform thickness. The range shifter 10 may be provided detachably.

[0054] A large number of slits 21 are formed inside the collimator section 20. Each slit 21 extends long, and the large number of slits 21 are arranged side by side with one another.

[0055] The collimator unit 20 spatially divides the incident proton beam and monotonically decreases the PVDR according to the traveling distance within the target body.

[0056] The material of the collimator portion 20 may be brass or tungsten.

[0057] 5, the proton beam incident on the collimator section 20 may be incident at different angles of incidence on each slit 21. The extension direction of each slit 21 corresponds to the angle of incidence of the incident proton beam, that is, the slits 21 are provided in line with the incident proton beam scanned by the scanning magnet.

[0058] FIG. 6 shows the results of a simulation of the side dose distribution on the surface of the subject according to the beam incidence angle-slit extension direction when a 161 MeV proton beam scanned by a scanning magnet is incident on two different types of collimator sections.

[0059] In the case of the present invention, when the incidence angle and the slit extension direction are aligned (defocusing slit), the dose contour line on the skin is flat, and the dose distribution is uniform even in the lesion. On the other hand, when the incidence angle and the slit extension direction are not aligned and are parallel to each other between the slits (parallel slit), the dose contour line on the skin is not flat but curved. In such a case, the dose distribution is not uniform even in the lesion.

[0060] The shortest extension length (d1) of the slit 21, i.e., the thickness of the collimator section 20, may be 1.5 to 10 times the maximum penetration depth of the proton beam. If the extension length (d1) is less than 1.5 times the maximum penetration depth of the proton beam, it is difficult to monotonically decrease the PVDR. If the extension length (d1) is more than 10 times the maximum penetration depth of the proton beam, the loss of the proton beam is too large, the treatment time becomes very long, and handling of the collimator becomes difficult.

[0061] In other embodiments, the width (d2) of the slits 21 may increase towards the outside of the collimator.

[0062] Figure 7 shows the results of a Monte Carlo simulation of the change in side dose ratio depending on the depth of the medium when the slit extension length is changed to 5, 7, and 10 cm for a 200 MeV proton beam with a maximum penetration depth of 4.52 cm in brass. The material of the collimator part is assumed to be brass, and the medium is assumed to be filled with water.

[0063] As shown in FIG. 7, it can be seen that the PVDR decreases approximately monotonically from an extension length of 7 cm, which is about 1.5 times the maximum penetration depth.

[0064] The scattering section 30 may be made of a metal plate, or may be made of a plurality of metal plates having different thicknesses.

[0065] Each scattering unit 30 is attached to a selection unit 50. The selection unit 50 is provided with a passage hole 51, and the proton beam that has passed through the collimator unit 20 and been spatially divided is incident on the passage hole 51. A user positions a scattering unit 30 having a desired degree of scattering among the multiple scattering units 30 in the passage hole 51.

[0066] The degree of scattering of the scattering unit 30 can be varied by adjusting the material and / or thickness of the metal plate. The metal plate may be made of a metal having a density of 10 to 25, and may specifically include any one of lead, bismuth, and tungsten.

[0067] The scattering unit 30 ensures that the proton beam is unsplit according to the depth of the tumor, i.e., the scattering unit 30 determines the depth at which the PVDR of the spatially split proton beam becomes lower than 1.2 or 1.1.

[0068] FIG. 8 shows the results of a Monte Carlo simulation calculation showing the adjustment of the side dose ratio of the proton beam at each depth according to the thickness of the lead scattering portion.

[0069] In the simulation, the proton beam energy was 161 MeV, the collimator was brass, the width was 2.5 mm, the slit width was 2.5 mm, the slit distance was 5 mm, and the slit extension length was 10 cm. The medium was assumed to be filled with water.

[0070] As shown in Figure 8, it can be seen that the depth at which the PVDR reaches 1.1 varies depending on the lead thickness in the scattering area.

[0071] The absorbing section 40 is located between the scattering section 30 and the lesion, and removes radiation generated or scattered by the proton beam from the range shifter 10, the collimator section 20, the scattering section 30, and the like.

[0072] The absorbent portion 40 has a density of 0.7 g / cm 3 or 2g / cm 3 A polymer with a density of 2 g / cm 3 or 6g / cm 3 The metal used for the absorbing portion 40 may be aluminum or titanium.

[0073] The sum of the thicknesses of the air layers between the collimator section 20 and the absorbing section 40 is adjustable and may be from 1 cm to 8 cm. The thickness of the air layer is the sum of the distance (1) between the collimator section 20 and the scattering section 30 and the distance (2) between the scattering section 30 and the absorbing section 40, as shown in FIG.

[0074] By adjusting the thickness of the air layer, the dose uniformity inside the tumor can be adjusted. If the thickness of the air layer is increased, the dose uniformity inside the tumor can be improved. However, the PVDR of the proton beam irradiated to the scalp will decrease.

[0075] The distance between the above-described conversion device 1 and the lesion is adjustable.

[0076] A method for treating a patient using the conversion device according to the first embodiment of the present invention will now be described.

[0077] First, the location of the lesion and the condition of the patient are identified and a treatment plan is made.

[0078] The treatment plan includes the maximum energy of the proton beam, the irradiation position and the treatment time, as well as the selection and arrangement position of the conversion device 1.

[0079] The conversion device 1 selects a configuration so that the proton beam maintains a split state and becomes unsplit at the lesion position. The selection of the scattering unit 30 is the key, and the selection of the scattering unit 30 takes into consideration the use of the range shifter 10 and the distance between the absorbing unit 40 and the lesion, etc.

[0080] After constructing the desired conversion device 1 and coupling it to the proton beam generator and positioning the patient, the proton beam is irradiated.

[0081] The proton beam passes through the range shifter 10 and moves to a shallow depth of penetration in the patient. It then passes through the collimator section 20 and is spatially divided, and the PVDR decreases monotonically as it progresses. The proton beam is scattered as it passes through the scattering section 30, and the depth at which it is switched to an undivided state is determined. The proton beam then passes through the absorbing section 40, where scattered radiation is removed, and then it is incident on the patient.

[0082] The proton beam maintains a high PVDR of 1.2 or greater in the patient's normal tissues, and becomes unfractionated and has a PVDR of 1.2 or less when it reaches the lesion, reducing the effects of the proton beam on the normal tissues and allowing for effective treatment with the proton beam on the lesions.

[0083] Second to fourth embodiments of the present invention will now be described with reference to FIGS.

[0084] 10, the collimator section 20 is composed of a first collimator 20a and a second collimator 20b. The first collimator 20a and the second collimator 20b are arranged along the direction of incidence of the proton beam. In other embodiments, three or more collimator sections 20 may be provided and may be made of different materials.

[0085] In the third embodiment of FIG. 11, the collimator section 20 is provided in a curved shape and has a concave shape toward the patient.

[0086] 12, the scattering section 30 includes a first scattering section 30a located close to the collimator section 20 and a second scattering section 30b located far from the collimator section 20. A plurality of first scattering sections 30a and second scattering sections 30b are provided. A user can combine the first scattering sections 30a and second scattering sections 30b to realize various degrees of scattering and adjust the depth at which the proton beam is switched to an unsplit state.

[0087] For example, if the metal plate of the first scattering section 30a is composed of 10 mm, 20 mm, and 30 mm, and the metal plate of the second scattering section 30b is composed of 3 mm, 5 mm, and 7 mm, the user can use metal plate thicknesses of 10 mm, 13 mm, 15 mm, 17 mm, 20 mm, etc. depending on the combination.

[0088] The first scattering section 30a and the second scattering section 30b may be spaced apart, in which case the total thickness of the air layer in the fourth embodiment includes the space between the first scattering section 30a and the second scattering section 30b.

[0089] The above-mentioned examples are merely illustrative of the present invention, and are not intended to limit the scope of the present invention. A person skilled in the art to which the present invention pertains can implement the present invention by modifying it in various ways, and therefore the technical scope of the present invention should be defined by the appended claims.

Claims

1. 1. A transformation device for transforming a treatment beam for treating a lesion in a target object, comprising: a collimator section into which the treatment beam is incident and in which a plurality of slits are formed; a scattering unit that scatters the treatment beam that has passed through the collimator unit, The treatment beam comprises a charged particle beam.

2. The conversion apparatus of claim 1 , wherein the charged particle beam comprises one of a proton beam, a helium ion beam, and a carbon ion beam.

3. The plurality of slits are formed side by side, The conversion device of claim 1 , wherein the slit spatially separates the treatment beam.

4. the treatment beam is incident on the plurality of slits at different angles of incidence; The conversion device according to claim 3 , wherein an extension direction of each of the slits is formed to correspond to the incident angle.

5. The conversion device according to claim 1 , wherein the collimator section includes a first collimator section and a second collimator section arranged along a traveling direction of the treatment beam.

6. The conversion device according to claim 1 , wherein the collimator portion is made of one of brass and tungsten.

7. The conversion device according to claim 1 , wherein the collimator portion is recessed toward the lesion.

8. The conversion device according to claim 1 , wherein the scattering unit has a plurality of scattering units each having a different scattering degree and is selectable by a user.

9. The scattering portion is A first scattering portion; and a second scattering section located between the first scattering section and the lesion; The conversion device according to claim 8 , wherein the first scattering section and the second scattering section each include a plurality of scattering sections each having a different scattering degree.

10. The treatment beam that has passed through the scattering section is irradiated onto the lesion, The conversion device of claim 1 , wherein the treatment beam is switched to a non-fractionated state at the lesion.

11. The conversion device of claim 1 , wherein the scattering portion includes a metal plate.

12. The metal of the metal plate has a density of 10 g / cm ３ or 25 g / cm ３ The conversion device according to claim 11 ,

13. 13. The conversion device of claim 12, wherein the metal of the metal plate includes one of lead, bismuth, and tungsten.

14. The treatment beam is converted into therapeutic spatially divided radiation while passing through the collimator section and the scattering section, The conversion device of claim 1 , further comprising an absorbing portion located between the scattering portion and the lesion, the absorbing portion absorbing at least a portion of the radiation.

15. The absorbing portion is Density is 0.7 g / cm ３ or 2 g / cm ３ and Density is 2g / cm ３ 6 g / cm ３ 15. The converter of claim 14, comprising any one of the metals:

16. 15. The conversion device according to claim 14, wherein the total thickness of the air layer between the collimator section and the absorber section is adjustable and is between 1 cm and 8 cm.

17. The conversion device of claim 14 , wherein the spacing between the absorber and the lesion is adjustable.

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