Adjusting device for particle flash momentum cooling
The problem of low-energy beam momentum diffusion and beam intensity loss is solved by using momentum cooling devices of wedge-shaped block clamping assembly and turntable assembly in proton therapy, achieving more efficient beam energy regulation and patient comfort improvement.
Patent Information
- Application Number
- CN202421203122.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-30
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-05-30
AI Technical Summary
In proton therapy, low-energy beams are difficult to achieve ultra-high dose rates, resulting in increased treatment time and reduced patient comfort, mainly due to beam momentum diffusion and beam intensity loss caused by traditional energy selection systems.
Using an adjustment device for particle flash momentum cooling, the beam current energy is adjusted instead of the traditional slit screening method by moving on the annular track through the wedge-shaped block clamping assembly and the turntable assembly.
It significantly increases the beam intensity after energy regulation, shortens the radiation treatment time, improves patient comfort, and reduces energy loss.
Smart Images
Figure CN222803080U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of medical technology, in particular to an adjustment device for particle flash momentum cooling. Background Art
[0002] In proton therapy, there has been a strong push in recent years to develop ultra-high dose rates to increase sparing of healthy tissues through the flash effect. However, in cyclotron-based proton therapy facilities, it is difficult to achieve ultra-high dose rates with low-energy beams. The main reason for this is that when the energy of the beam is reduced to the level required for proton therapy, the momentum of the beam spreads greatly, causing a huge loss of beam intensity in the traditionally used momentum or energy selection slits.
[0003] Since proton cyclotrons produce beams of fixed energy (230-250 MeV), in order to achieve the energy required for clinical use (70-230 MeV), an energy selection system (ESS) consisting of an energy degrader with adjustable thickness is required. Multiple Coulomb scattering and distance dispersion in the energy degrader increase the lateral emittance (phase space area) and momentum spread of the beam. For the lowest energy (70-100 MeV), the transmission through the ESS is usually less than 0.1%. This loss will increase the treatment radiation time and reduce the comfort of the patient.
[0004] The schematic diagram of a conventional ESS is shown in Figure 1 As shown, at the entrance of the dipole magnet D, the momentum of the proton beam is p±Δp. When the beam passes through D, particles with high momentum (i.e., p+Δp) bend less, while particles with low momentum (i.e., p-Δp) bend more. A pair of focusing magnets (Q1 and Q2) is used to focus the beam at the momentum selection slit, screening out high-energy and low-energy protons and retaining only protons with the required energy. A large number of protons whose momentum does not meet the required momentum are blocked in the slit, causing the beam intensity to drop by 6-10 times. Summary of the invention
[0005] In view of the defects and shortcomings of the above-mentioned prior art, the utility model proposes an adjustment device for particle flash momentum cooling, comprising a turntable assembly 1, a plurality of wedge block clamping assemblies 2, and a support assembly 3. The wedge block clamping assembly 2 is fixed on the turntable assembly 1 and moves on the annular track 9. The support assembly 3 is connected to the turntable assembly 1 to support and adjust the position of the turntable assembly 1. The turntable assembly 1, the wedge block clamping assembly 2, and the support assembly 3 are connected with screws.
[0006] The wedge block clamping assembly 2 is composed of a wedge block 4, a base 5, a pressing piece 6 and a clamping slot 7. The handle portion of the wedge block 4 is clamped by the base 5 and the pressing piece 6, and the base 5 is installed in the clamping slot of the clamping slot 7.
[0007] Further, the turntable assembly 1 includes a ring rail base plate 8, a ring rail 9, a slider 10, a drag fastener 11, a synchronous belt and pulley 12, a reducer 13, a servo motor 14, a coupling 15, a drive shaft 16, and a bracket 17. The ring rail 9 is fixed on the ring rail base plate 8, one end of the drag fastener 11 is fixed to the slider 10 with a screw, and the other end is fixed to the synchronous belt and pulley 12, so that the synchronous belt and pulley 12 can drive 18 sliders to travel around the ring rail 9. The servo motor 14 and the reducer 13 are fixed together and connected to the drive shaft 16 through the coupling 15. The drive shaft 16 is fixed to the synchronous belt and pulley 12 with screws, so that the servo motor 14 can drive the synchronous belt and pulley 12 to rotate. The reducer 13 and the servo motor 14 are fixed to the ring rail base plate 8 with a bracket 17.
[0008] The support assembly 3 includes a welding bracket 18, a linear guide 19, a bolt 20, a chassis 21, and a foot 22. The welding bracket 18 is fixed to the linear guide 19 with screws, and the linear guide 19 is fixed to the chassis 21. The welding bracket 18 can slide forward and backward on the chassis 21 through the linear guide 19, and can be used to adjust the position of the wedge block relative to the beam line vacuum window, and lock the position with the chassis 21 through the bolt 20. Four foots 22 are placed under the chassis 21 to adjust the height and flatness of the entire device, thereby affecting the posture of the wedge block to adapt it to the beam.
[0009] Further, the number of the wedge block clamping assemblies 2 is 18.
[0010] Furthermore, the length and width of the wedge block 4 are 80 mm and 80 mm respectively.
[0011] Compared with the prior art, the utility model has the following beneficial effects:
[0012] Using wedge blocks to adjust beam energy can significantly increase the beam intensity after energy adjustment, shorten the radiotherapy time, and improve patient comfort compared to screening through slits. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is a schematic diagram of a conventional ESS. (This is a background art diagram)
[0014] Figure 2 Schematic diagram of ESS using momentum cooling method.
[0015] Figure 3 It is the front view of the utility model.
[0016] Figure 4 It is a side view of the utility model.
[0017] Figure 5 This is a structural diagram of the wedge block clamping assembly of the utility model.
[0018] Figure 6 It is an axonometric view of the annular track assembly of the present utility model.
[0019] Figure 7 It is a cross-sectional view of the annular track assembly of the present utility model.
[0020] Figure 8 It is an axonometric view of the support assembly of the utility model.
[0021] Fig. 9 This is a structural diagram of a welding bracket of a support assembly of the utility model.
[0022] In the figure: 1-turntable assembly, 2-wedge block clamping assembly, 3-support assembly, 4-wedge block, 5-base, 6-pressing plate, 7-card slot, 8-ring rail base plate, 9-ring rail, 10-slider, 11 drag fastener, 12-synchronous belt and pulley, 13-reducer, 14-servo motor, 15-coupling, 16-drive shaft, 17-bracket, 18-welding bracket, 19-linear guide, 20-bolt, 21-chassis, 22-foot. DETAILED DESCRIPTION
[0023] The utility model will be further described below in conjunction with the accompanying drawings.
[0024] The utility model adopts a method called "momentum cooling" to reduce the longitudinal emittance (momentum diffusion) after energy loss and improve the beam transmission efficiency. For example, at 70MeV energy, it is about 30 times higher than the existing technology. In ESS, wedges are used instead of slits to cool the momentum diffusion, avoiding a large number of particle losses. Figure 2 The principle of momentum cooling is illustrated. The geometry of the wedge is chosen so that particles with different momentum encounter different thicknesses of material and thus lose more (high energy particles) or less (low energy particles) energy in the wedge to balance the momentum spread (p-Δp) after the wedge. Thus, the momentum spread after the wedge is reduced while the beam loss is greatly reduced.
[0025] An adjustment device for particle flash momentum cooling includes a turntable assembly 1, a plurality of wedge-shaped block clamping assemblies 2, and a support assembly 3. The wedge-shaped block clamping assembly 2 is fixed on the turntable assembly 1 and moves on a circular track 9. The support assembly 3 is connected to the turntable assembly 1 to support and adjust the position of the turntable assembly 1. The turntable assembly 1, the wedge-shaped block clamping assembly 2, and the support assembly 3 are connected by screws.
[0026] like Figure 5 As shown, the wedge block clamping assembly 2 is composed of a wedge block 4, a base 5, a pressing piece 6 and a clamping slot 7. The handle portion of the wedge block 4 is clamped by the base 5 and the pressing piece 6, and the base 5 is installed in the clamping slot of the clamping slot 7.
[0027] The energy gradient determines how many wedges are used and the thickness of each wedge through Monte Carlo simulation. Here is an example of one of the segmentation schemes:
[0028] With 10MeV energy as a gradient, 17 wedges can be generated, such as 70MeV, 80MeV...220MeV, 230MeV, etc. In actual application, a 240MeV wedge is added, and a total of 18 wedges are used. Other energy division schemes can also be used. Each wedge has a different thickness, corresponding to blocking proton beams of different energies, but the length and width are 80mm*80mm, and polyethylene material is used but not limited to polyethylene. The scheme for adjusting the device is as follows Figure 3 , 4 shown.
[0029] like Figure 6 , 7 As shown, the turntable assembly 1 includes a ring rail base plate 8, a ring rail 9, a slider 10, a drag fastener 11, a synchronous belt and pulley 12, a reducer 13, a servo motor 14, a coupling 15, a drive shaft 16, and a bracket 17. The ring rail 9 is fixed on the ring rail base plate 8, one end of the drag fastener 11 is fixed to the slider 10 with a screw, and the other end is fixed to the synchronous belt and pulley 12, so that the synchronous belt and pulley 12 can drive 18 sliders to travel around the ring rail 9. The servo motor 14 and the reducer 13 are fixed together and connected to the drive shaft 16 through the coupling 15. The drive shaft 16 is fixed to the synchronous belt and pulley 12 with screws, so that the servo motor 14 can drive the synchronous belt and pulley 12 to rotate. The reducer 13 and the servo motor 14 are fixed to the ring rail base plate 8 with a bracket 17.
[0030] like Figure 8 , 9 As shown, the support assembly 3 includes a welding bracket 18, a linear guide 19, a bolt 20, a chassis 21, and a foot 22. The welding bracket 18 is fixed to the linear guide 19 with screws, and the linear guide 19 is fixed to the chassis 21. The welding bracket 18 can slide forward and backward on the chassis 21 through the linear guide 19, which can be used to adjust the position of the wedge block relative to the beam line vacuum window, and lock the position with the chassis 21 through the bolt 20. Four foots 22 are placed under the chassis 21 to adjust the height and flatness of the entire device, thereby affecting the posture of the wedge block to adapt it to the beam.
[0031] 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 device for adjusting particle flash momentum cooling, characterized in that: include: A turntable assembly (1), a plurality of wedge-shaped block clamping assemblies (2), and a support assembly (3); the wedge-shaped block clamping assembly (2) is fixedly connected to the turntable assembly (1) and moves on a circular track (9); the support assembly (3) is fixedly connected to the turntable assembly (1) and plays a role in supporting and adjusting the position of the turntable assembly (1); The wedge block clamping assembly (2) is composed of a wedge block (4), a base (5), a pressing sheet (6) and a slot (7); the handle portion of the wedge block (4) is clamped by the base (5) and the pressing sheet (6), and the base (5) is installed in the slot of the slot (7).
2. The device for adjusting particle flash momentum cooling according to claim 1, characterized in that: The turntable assembly (1) comprises a ring rail base plate (8), a ring rail (9), a slider (10), a drag fastener (11), a synchronous belt and a pulley (12), a reducer (13), a servo motor (14), a coupling (15), a drive shaft (16), and a bracket (17); the ring rail (9) is fixed on the ring rail base plate (8), one end of the drag fastener (11) is fixed on the slider (10) by a screw, and the other end is fixed to the synchronous belt and the pulley (12), so that The step belt and the pulley (12) can drive 18 sliders to travel around the circular track (9); the servo motor (14) and the reducer (13) are fixed together and connected to the driving shaft (16) through a coupling (15); the driving shaft (16) is fixed to the synchronous belt and the pulley (12) by screws, and the servo motor (14) can drive the synchronous belt and the pulley (12) to rotate; the reducer (13) and the servo motor (14) are fixed to the circular track bottom plate (8) by a bracket (17).
3. The device for adjusting particle flash momentum cooling according to claim 1, characterized in that: The support assembly (3) comprises a welding bracket (18), a linear guide rail (19), bolts (20), a chassis (21), and feet (22); the welding bracket (18) is fixed to the linear guide rail (19) by screws, and the linear guide rail (19) is fixed to the chassis (21), so that the welding bracket (18) can slide forward and backward on the chassis (21) through the linear guide rail (19) and is locked with the chassis (21) by the bolts (20); four feet (22) are arranged under the chassis (21) for adjusting the height and flatness of the entire device.
4. The device for adjusting particle flash momentum cooling according to claim 1, characterized in that: The number of wedge block clamping assemblies is 18.
5. The device for adjusting particle flash momentum cooling according to claim 1, characterized in that: The fixed connection is via screw connection.
6. A device for adjusting particle flash momentum cooling according to any one of claims 1 to 5, characterized in that: The length and width of the wedge block (4) are 80 mm and 80 mm respectively, and the thickness is different. With an energy gradient of 10 MeV, 18 wedge blocks of different thicknesses corresponding to energies of 70 MeV, 80 MeV, ..., 230 MeV, and 240 MeV can be generated.