Therapeutic head nozzle for particle flashing

Abstract

The utility model relates to a treatment head nozzle for particle flashing, and belongs to the technical field of medical treatment. Comprising two groups of ionization chambers which work in air and monitor beam dose, position and shape; the positioning and anti-collision detection device is used for protecting the safety of a patient, and needs to quickly respond and stop; the pre-absorber assembly is used for adjusting beam energy in a range of 0-70MeV, and controlling stretching and retracting of a pre-absorber block through a driving structure; the nozzle range moving device is used for adjusting the distance between the window and the body surface of the patient; and the mechanical supporting structure and the shell are used for protecting the internal structure of the nozzle from being extruded. The telescopic pre-absorber is adopted, and the telescopic pre-absorber is folded under the condition that the pre-absorber is not needed in tumor treatment, so that the influence on beam current is reduced as much as possible, the radiation accuracy is improved, and the neutron radiation is reduced. The telescopic nozzle is close to the human body as much as possible during treatment, scattering is reduced, beam quality is improved, and radiation accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the field of medical technology, in particular to a treatment head nozzle used for particle flashing. Background Art

[0002] After years of development, precision radiotherapy technology has been widely used, but the existing technology is still limited by the tolerance dose of normal tissue and cannot achieve the optimal goal of tumor treatment. Flash therapy (Flash-RT) is a radiotherapy technology that uses ultra-high dose rate beams (UHDR) for irradiation. It can significantly reduce radiation damage to normal tissues while maximizing tumor treatment.

[0003] The radiation dose rate of existing conventional proton radiotherapy equipment is 2Gy / s, and the dose ionization chamber in the nozzle is required to monitor the beam dose and the shape and position of the beam cross section to ensure that the quality of the beam entering the human body meets the requirements. However, this is far from enough for the dose rate of at least 40Gy / s for flash.

[0004] Proton beams are generated by accelerators. The energy used to treat tumors is between 70 MeV and 245 MeV (mega-electron volts), corresponding to a range of 4-37 cm in water. Energy is adjusted by an energy degrader. However, for the treatment of superficial skin or intraocular tumors, the range may be less than 4 cm, so a pre-absorber in the nozzle is required to further block and absorb energy below 70 MeV. In other manufacturers' solutions, some pre-absorbers are fixed, that is, 70 MeV is absorbed for all beams, and the rest are adjusted by energy degraders to meet the beam energy requirements of different tumor treatment plans. Although this solution is simple, a large number of secondary neutrons will be generated when protons pass through the pre-absorber, causing unnecessary irradiation to the patient's healthy tissues. At the same time, the thickness and space occupied by the pre-absorber itself increase the beam travel, which will cause beam scattering and reduce beam quality. How to treat tumors to the maximum extent while reducing radiation damage to normal tissues is worth exploring. Summary of the invention

[0005] The purpose of the present invention is to address the defects and shortcomings of the above-mentioned prior art and propose a treatment head nozzle for particle flashing. The device integrates the two functions of nozzle extension and pre-absorber extension, further improving the beam quality, reducing radiation to patients, and improving safety.

[0006] A treatment head nozzle for particle flashing includes an ionization chamber A 44, an ionization chamber B 45, a positioning and anti-collision detection device, a pre-absorber assembly 38, a nozzle range moving device 39, a mechanical support structure and a housing.

[0007] The pre-absorber assembly 38 is controlled by a linear telescopic device, and includes a pre-absorber partition 1, a pre-absorber block 2, a pre-absorber block clip A3, a pre-absorber block clip B4, a stepper motor 5, a coupling 6, a motor bracket 7, a lead screw bracket 8, a linear guide 9, a photoelectric switch 10, a trapezoidal lead screw 11, and a mechanical limit 12. The motor bracket 7, the linear guide 9, the photoelectric switch 10, and the mechanical limit 12 are fixed on the pre-absorber partition 1, the pre-absorber block 2 is placed in the slots of the pre-absorber block clip A3 and the pre-absorber block clip B4, and then the pre-absorber block clip A3 and the pre-absorber block clip B4 are each fixed to the linear guide 9 with screws. The stepper motor 5 is fixed to the motor bracket 7 with screws, the trapezoidal lead screw 11 passes through the lead screw bracket 8 and the lead screw bracket 8 is fixed to the pre-absorber partition 1 with screws, and then the output shaft of the stepper motor 5 and the trapezoidal lead screw 11 are locked through the coupling 6. At this time, the pre-absorption block 2, the pre-absorption block clip A3, and the pre-absorption block clip B4 as a whole can make linear reciprocating motion along the linear guide 9 under the drive of the stepping motor 5, the coupling 6, and the trapezoidal screw 11, and the position signal is monitored by the photoelectric switch 10, and the extreme position is limited by the mechanical limit 12.

[0008] The nozzle range moving device 39 adopts a telescopic structure, including a hinge base 13, lifting arm hinges A14, B 33, C 34, D 35, linear guides A15, B 36, a nozzle adapter plate 16, a lifting arm 17, an electric cylinder adapter 18, an electric cylinder bracket 19, and an electric cylinder 20. The hinge base 13 and the linear guide A15 are fixed to the preabsorber partition 1 in the preabsorber assembly with screws, and the linear guide B 36 is fixed to the nozzle adapter plate 16. The lifting arm hinges A14 and B33 are symmetrically connected to the linear guide A15, and the lifting arm hinges A14 and B33 can slide linearly on the linear guide A15. Similarly, the lifting arm hinges C34 and D35 are symmetrically connected to the linear guide B36, and the lifting arm hinges C34 and D35 can slide linearly on the linear guide B36. Then, the two lifting arms 17 are hinged together through the hinge base 13 and the lifting arm hinges A14, B33, C34, and D35 to form a parallelogram multi-link. The electric cylinder bracket 19 is fixed on the nozzle adapter plate 16, the electric cylinder adapter 18 is fixed on the pre-absorber partition 1, the cylinder wall of the electric cylinder 20 is fixed to the electric cylinder bracket 19, and the piston rod is fixed to the electric cylinder adapter 18, all with screws. The extension and retraction of the electric cylinder 20 can drive the connecting rod to extend and retract, thereby achieving the purpose of lifting and lowering the pre-absorber. The extension and retraction stroke is controlled by the servo motor in the electric cylinder 20.

[0009] Further, the ionization chamber A 44 and the ionization chamber B 45 share the ionization chamber bracket A21, the ionization chamber bracket B 22, and the ionization chamber bracket C 23. The ionization chamber A 44 also includes a dose and strip function module A24, and the ionization chamber B 45 also includes a dose and strip function module B 37. The ionization chamber bracket C 23 is fixed on the pre-absorber partition 1. The dose and strip function module A24 and the dose and strip function module B 37 are concentrically stacked and distributed. The ionization chamber bracket A21 and the ionization chamber bracket B 22 are used to lock them, and then the ionization chamber bracket A21 and the ionization chamber bracket B 22 are fixed to the ionization chamber bracket C 23 with screws, so that the relative positions of the dose and strip function module A24, the dose and strip function module B 37 and the pre-absorption block 2 can be fixed, so that the physical parameters are kept as consistent as possible when the beam is emitted.

[0010] The positioning and anti-collision detection device comprises a sensor 25 and a nozzle top plate 26. Two to three sensors 25 are arranged on the left and right of the nozzle top plate 26 to detect the distance between the nozzle top plate 26 and the patient to prevent collision.

[0011] The mechanical support structure and the housing include a nozzle window frame 27, a corrugated outer jacket 28, a nozzle sleeve 29, a treatment head frame 30, a press plate 31, and a decorative housing buckle plate 32. The nozzle adapter plate 16 and the treatment head frame 30 are bolted together, and the nozzle window frame 27 is connected to the pre-absorber partition 1 and the nozzle top plate 26. The corrugated outer jacket 28 shields and protects the internal parts of the nozzle, and expands and contracts in the nozzle sleeve 29 with the connecting rod. The nozzle sleeve 29 is fixed on the nozzle adapter plate 16, the press plate 31 is installed on the outer wall of the nozzle sleeve 29, and the decorative housing buckle plate 32 is fixed on the press plate 31 to fix the housing.

[0012] Furthermore, the sensor is an ultrasonic sensor.

[0013] Furthermore, the linear telescopic device is an offset trapezoidal lead screw or a linear guide rail.

[0014] Furthermore, the telescopic structure is a parallelogram multi-link structure, and can also be a structure of a lead screw plus a slide rail, a gear rack, a guide rod plus hydraulic pressure, etc.

[0015] Beneficial effects of the utility model:

[0016] 1. The ionization chamber used in this device has two functions at the same time, and two are used to eliminate accidents caused by failures through redundancy. The ionization chamber can detect dose rates in the range of more than 40Gy / s.

[0017] 2. The pre-absorber is retractable. In most tumor treatments, the pre-absorber is not needed. It can be folded to minimize the impact on the beam, improve radiation accuracy, and reduce neutron radiation.

[0018] 3. Retractable nozzle. During treatment, keep the nozzle as close to the human body as possible to reduce scattering, improve beam quality, and improve radiation accuracy. 2-3 ultrasonic sensors are arranged at the front end of the nozzle to detect the distance from the body surface and prevent collision accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the treatment head.

[0020] Figure 2 A structural diagram of the pre-absorber assembly.

[0021] Figure 3 This is a cross-sectional view of the nozzle when it is extended.

[0022] Figure 4 It is a side view of the nozzle when it is extended.

[0023] Figure 5 This is a structural diagram of the nozzle in the retracted state.

[0024] Figure 6 This is the overall structure diagram when the nozzle is extended.

[0025] In the figure: 1-preabsorber partition; 2-preabsorber block; 3-preabsorber block clip A; 4-preabsorber block clip B; 5-stepping motor; 6-coupling; 7-motor bracket; 8-screw bracket; 9-linear guide; 10-photoelectric switch; 11-trapezoidal screw; 12-mechanical limit; 13-hinge base; 14-lifting arm hinge A; 15-linear guide A; 16-nozzle adapter plate; 17-lifting arm; 18-electric cylinder adapter; 19-electric cylinder bracket; 20-electric cylinder; 21-ionization chamber bracket A; 22-ionization chamber bracket B; 23-ionization chamber bracket C; 24-agent Dose and strip function module A; 25-ultrasonic sensor; 26-nozzle top plate; 27-nozzle window frame; 28-corrugated jacket; 29-nozzle sleeve; 30-treatment head frame; 31-pressing plate; 32-decorative shell buckle plate; 33-lifting arm hinge B; 34-lifting arm hinge C; 35-lifting arm hinge D; 36-linear guide B; 37-dose and strip function module B; 38-pre-absorber assembly, 39-nozzle range moving device, 40-protective film, 41-helium chamber, 42-profile monitoring device, 43-vacuum window; 44-ionization chamber A, 45-ionization chamber B. DETAILED DESCRIPTION

[0026] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0027] Figure 1This is a schematic diagram of the structure of the treatment head. The treatment head converts the proton beam energy properties, including energy, flux, cross-sectional shape, position, energy dispersion, emittance, etc., into the beam properties required for treatment, including energy, energy adjustment, irradiation field, dose rate, trailing edge drop, etc. The current mainstream pencil beam treatment head has the following functions:

[0028] 1) Beam performance conversion. Such as lateral beam expansion, longitudinal energy modulation, energy conversion, etc.;

[0029] 2) Beam performance monitoring. Such as dose ionization chamber, beam position monitoring device, etc.;

[0030] 3) Conformers, such as patient aperture, patient compensator, nozzle, etc.

[0031] Figure 1 The dotted box in the figure is the nozzle structure of the pencil beam scanning treatment head, including:

[0032] 1) Ionization chambers A and B: work in air and monitor beam dose, position, and shape;

[0033] 2) Positioning and anti-collision detection device: to protect the patient's safety, quick response and stop are required;

[0034] 3) Pre-absorber assembly: adjust the beam energy in the range of 0 to 70 MeV and control the expansion and contraction of the pre-absorber block through the drive structure;

[0035] 4) Nozzle range moving device: adjust the distance between the window and the patient's body surface;

[0036] 5) Mechanical support structure and housing: used to protect the internal structure of the nozzle from being squeezed.

[0037] The protective film 40 covers the window of the range moving device 39, shielding and protecting the internal structures such as the ionization chamber. The proton beam in the nozzle comes from the upstream beam transmission system, enters the treatment head through the vacuum window 43, first passes through the profile monitoring device 42 to obtain the contour shape of the beam cross section, and then passes through the helium chamber 41 to enter the ionization chamber. The helium chamber 41 is filled with helium and its outlet position is sealed, while the nozzle works in an air environment.

[0038] Figure 2It is a structural diagram of the pre-absorber assembly, which is fixed at the lower end of the nozzle. The device uses an offset trapezoidal screw and a linear guide to control the extension and retraction, including but not limited to other linear motion structures, with two sensor limits at each end, one of which is used as a safety measure to stop the beam emission after detecting a fault, and a mechanical limit device is set to protect the motor. The pre-absorber material is PMMA, and materials such as graphite and beryllium can also be used. Among them, the pre-absorber assembly 38 includes a pre-absorber partition 1, a pre-absorber block 2, a pre-absorber block clip A3, a pre-absorber block clip B 4, a stepper motor 5, a coupling 6, a motor bracket 7, a screw bracket 8, a linear guide 9, a photoelectric switch 10, a trapezoidal screw 11, and a mechanical limit 12. The motor bracket 7, the linear guide 9, the photoelectric switch 10, and the mechanical limit 12 are fixed on the pre-absorber partition 1, the hinge base 13 is located on the other side, the pre-absorber block 2 is placed in the slots of the pre-absorber block clip A 3 and the pre-absorber block clip B 4, and then the pre-absorber block clip A 3 and the pre-absorber block clip B 4 are fixed to the linear guide 9 with screws. The stepper motor 5 is fixed to the motor bracket 7 with screws, the trapezoidal lead screw 11 passes through the lead screw bracket 8 and the lead screw bracket 8 is fixed to the pre-absorber partition 1 with screws, and then the output shaft of the stepper motor 5 and the trapezoidal lead screw 11 are locked by the coupling 6. At this time, the pre-absorber block 2, the pre-absorber block clip A 3, and the pre-absorber block clip B 4 as a whole can be driven by the stepper motor 5, the coupling 6, and the trapezoidal lead screw 11 to make linear reciprocating motion along the linear guide 9, and the position signal is monitored by the photoelectric switch 10, and the limit position is limited by the mechanical limit 12.

[0039] Figure 3 This is a cross-sectional view of the nozzle when it is extended. Figure 4 This is a side view of the nozzle when it is extended. Figure 5 This is a structural diagram of the nozzle in the retracted state. Figure 6 This is the overall structure diagram when the nozzle is extended.

[0040] The nozzle range moving device 39 includes a hinge base 13, lifting arm hinges A14, B 33, C 34, D 35, linear guides A15, B 36, a nozzle adapter plate 16, a lifting arm 17, an electric cylinder adapter 18, an electric cylinder bracket 19, and an electric cylinder 20. The linear guide A15 is fixed to the preabsorber partition 1 in the preabsorber assembly with screws, and the linear guide B 36 is fixed to the nozzle adapter plate 16. The lifting arm hinges A14 and B33 are symmetrically connected to the linear guide A15, and the lifting arm hinges A14 and B33 can slide linearly on the linear guide A15. Similarly, the lifting arm hinges C34 and D35 are symmetrically connected to the linear guide B36, and the lifting arm hinges C34 and D35 can slide linearly on the linear guide B36. Then, the two lifting arms 17 are hinged together through the hinge base 13 and the lifting arm hinges A14, B33, C34, and D35 to form a parallelogram multi-link. The electric cylinder bracket 19 is fixed to the nozzle adapter plate 16, the electric cylinder adapter 18 is fixed to the pre-absorber partition 1, the cylinder wall of the electric cylinder 20 is fixed to the electric cylinder bracket 19, and the piston rod is fixed to the electric cylinder adapter 18, all of which are screws. Then, the telescopic movement of the electric cylinder 20 can drive the connecting rod to telescope, so as to achieve the purpose of lifting the pre-absorber, and the telescopic stroke is controlled by the servo motor in the electric cylinder 20. The telescopic structure can also use other methods such as screw plus slide rail, gear rack, guide rod plus hydraulic pressure, etc.

[0041] Ionization chamber A 44 and ionization chamber B 45 share ionization chamber bracket A21, ionization chamber bracket B 22, ionization chamber bracket C23, ionization chamber A 44 also includes dose and strip function module A24, and ionization chamber B 45 also includes dose and strip function module B37. Ionization chamber bracket C 23 is fixed on the pre-absorber partition 1. Dose and strip function module A24 and dose and strip function module B 37 are concentrically stacked and distributed. They are locked by using ionization chamber bracket A21 and ionization chamber bracket B 22, and then ionization chamber bracket A21 and ionization chamber bracket B 22 are fixed on ionization chamber bracket C 23 with screws, so that the relative positions of dose and strip function module A24, dose and strip function module B 37 and pre-absorption block 2 can be fixed, so that the physical parameters are kept as consistent as possible when the beam is emitted.

[0042] The positioning and anti-collision detection device includes a sensor 25 and a nozzle top plate 26. Two to three sensors 25 are arranged on the left and right of the nozzle top plate 26 to detect the distance between the nozzle top plate 26 and the patient to prevent collision. Other ultrasonic sensors with distance detection functions can also be used. A contact sensor or a spring plate can also be added to stop within a few tens of milliseconds of response time and a few hundred microns after touching the human body, and the beam is cut off, which can further improve safety. The telescopic range is greater than 250mm.

[0043] The mechanical support structure and the housing include a nozzle window frame 27, a corrugated jacket 28, a nozzle sleeve 29, a treatment head frame 30, a pressure plate 31, and a decorative housing buckle plate 32. The nozzle window frame 27 connects the pre-absorber baffle 1 and the nozzle top plate 26. The corrugated jacket 28 shields and protects the internal parts of the nozzle, and expands and contracts in the nozzle sleeve 29 with the connecting rod. The nozzle adapter plate 16 and the treatment head frame 30 are bolted together. The treatment head frame 30 serves as a transfer connection between the nozzle and other parts of the treatment head, and can be regarded as a fixed reference part in this device. The nozzle window frame 27 connects the pre-absorber baffle 1 and the nozzle top plate 26. The corrugated jacket 28 shields and protects the internal parts of the nozzle, and expands and contracts in the nozzle sleeve 29 with the connecting rod. The nozzle sleeve 29 is fixed on the nozzle adapter plate 16, and the wire pressing plate 31 is installed on the outer wall of the nozzle sleeve 29 for arranging all cables in the nozzle such as ionization chamber cables and motor cables. The decorative shell buckle plate 32 is fixed on the wire pressing plate 31 for fixing the shell.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A treatment head nozzle for particle flashing, characterized in that: include: Ionization chamber A (44), ionization chamber B (45), positioning and anti-collision detection device, pre-absorber assembly (38), nozzle range movement device (39), mechanical support structure and housing; The pre-absorber assembly (38) is controlled by a linear telescopic device, and comprises a pre-absorber partition (1), a pre-absorber block (2), a pre-absorber block clip A (3), a pre-absorber block clip B (4), a stepping motor (5), a coupling (6), a motor bracket (7), a lead screw bracket (8), a linear guide rail (9), a photoelectric switch (10), a trapezoidal lead screw (11), and a mechanical limiter (12); the motor bracket (7), the linear guide rail (9), the photoelectric switch (10), and the mechanical limiter (12) are fixed on the pre-absorber partition (1), the pre-absorber block (2) is placed in the slots of the pre-absorber block clip A (3) and the pre-absorber block clip B (4), and the pre-absorber block clip A (3), the pre-absorber block clip B (4 ) is fixed to the linear guide rail (9) by screws, the stepper motor (5) is fixed to the motor bracket (7) by screws, the trapezoidal lead screw (11) passes through the lead screw bracket (8), the lead screw bracket (8) is fixed to the pre-absorber partition (1) by screws, the output shaft of the stepper motor (5) and the trapezoidal lead screw (11) are locked by the coupling (6), when in use, the pre-absorber block (2), the pre-absorber block clip A (3), and the pre-absorber block clip B (4) as a whole can be driven by the stepper motor (5), the coupling (6), and the trapezoidal lead screw (11) to make linear reciprocating motion along the linear guide rail (9), the photoelectric switch (10) is used to monitor the position signal, and the mechanical limit (12) is used to limit the limit position; The nozzle range moving device (39) adopts a telescopic structure, including a hinge base (13), lifting arm hinges A (14), B (33), C (34), D (35), linear guide rails A (15), B (36), a nozzle adapter plate (16), a lifting arm (17), an electric cylinder adapter (18), an electric cylinder bracket (19), and an electric cylinder (20); the linear guide rail A (15) is fixed to the preabsorber partition (1) in the preabsorber assembly with screws, the linear guide rail B (36) is fixed to the nozzle adapter plate (16), the lifting arm hinges A (14), B (33) are symmetrically connected to the linear guide rail A (15), and the lifting arm hinges A (14), B (33) can be moved in the linear The lifting arms (17) are connected to the linear guide rail (15) and slide linearly on the linear guide rail (15). Similarly, the lifting arm hinges C (34) and D (35) are symmetrically connected to the linear guide rail B (36). The lifting arm hinges C (34) and D (35) can slide linearly on the linear guide rail B (36). The two lifting arms (17) are hinged together through the hinge base (13) and the lifting arm hinges A (14), B (33), C (34) and D (35) to form a parallelogram multi-link. The electric cylinder bracket (19) is fixed to the nozzle adapter plate (16), the electric cylinder adapter (18) is fixed to the pre-absorber partition (1), the cylinder wall of the electric cylinder (20) is fixed to the electric cylinder bracket (19), and the piston rod is fixed to the electric cylinder adapter (18).

2. A treatment head nozzle for particle flashing according to claim 1, characterized in that: The ionization chamber A (44) and the ionization chamber B (45) share an ionization chamber support A (21), an ionization chamber support B (22), and an ionization chamber support C (23); the ionization chamber A (44) further comprises a dose and strip function module A (24); the ionization chamber B (45) further comprises a dose and strip function module B (37); the ionization chamber support C (23) is fixed on the pre-absorber partition (1); the dose and strip function module A (24) and the dose and strip function module B (37) are coaxially stacked and locked by the ionization chamber support A (21) and the ionization chamber support B (22); the ionization chamber support A (21) and the ionization chamber support B (22) are fixed on the ionization chamber support C (23) by screws; The mechanical support structure and the shell include a nozzle window outer frame (27), a corrugated outer jacket (28), a nozzle sleeve (29), a treatment head frame (30), a press plate (31), and a decorative shell buckle plate (32); the nozzle adapter plate (16) and the treatment head frame (30) are bolted together, the nozzle window outer frame (27) is connected to the pre-absorber partition (1) and the nozzle top plate (26), the corrugated outer jacket (28) shields and protects the internal parts of the nozzle, and expands and contracts in the nozzle sleeve (29) along with the connecting rod, the nozzle sleeve (29) is fixed on the nozzle adapter plate (16), the press plate (31) is installed on the outer wall of the nozzle sleeve (29), and the decorative shell buckle plate (32) is fixed on the press plate (31) to fix the shell; The positioning and anti-collision detection device comprises a sensor (25) and a nozzle top plate (26); 2-3 sensors (25) are arranged on the left and right of the nozzle top plate (26) for detecting the distance between the nozzle top plate and the patient to prevent collision.

3. A treatment head nozzle for particle flashing according to claim 1, characterized in that: The linear telescopic device is an offset trapezoidal lead screw or a linear guide rail.

4. A treatment head nozzle for particle flashing according to claim 1, characterized in that: The telescopic structure is a parallelogram multi-link, a lead screw plus a slide rail, a gear rack, a guide rod and hydraulic pressure.

5. A treatment head nozzle for particle flashing according to claim 2, characterized in that: The sensor (25) is an ultrasonic sensor.

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