A miniature wireless pyroelectric X-ray source

Abstract

This invention relates to the field of X-ray generating equipment technology, specifically disclosing a miniature wireless pyroelectric X-ray source, comprising a conversion target, a target adapter ring, an insulating shell, an optical fiber, a graphene electrode, a pyroelectric crystal, a crystal adapter base, a getter, and a laser transmission window; one end of the target adapter ring is connected to the conversion target; one end of the pyroelectric crystal is connected to the graphene electrode; the other end of the pyroelectric crystal is grounded and connected to the crystal adapter base; one end of the laser transmission window is connected to the crystal adapter base, and the other end of the laser transmission window is connected to the optical fiber; the getter is configured to be sleeved on the crystal adapter base; the conversion target, target adapter ring, insulating shell, graphene electrode, pyroelectric crystal, crystal adapter base, getter, and laser transmission window are all encapsulated within the insulating shell; this miniature wireless pyroelectric X-ray source does not require a high-voltage power supply, does not require heating the cathode to generate electrons, has low power consumption, and can generate X-rays wirelessly, enabling remote control.

Description

Technical Field

[0001] This invention relates to the field of X-ray generating equipment technology, and specifically to a miniature wireless pyroelectric X-ray source. Background Technology

[0002] Brachytherapy, also known as internal radiation therapy, is a radiotherapy technique that places a radiation source directly inside or next to the tumor tissue for irradiation.

[0003] Photon beam sources, as an important type of radiation source for brachytherapy, have the advantage of generating high-energy photons. These beams possess strong penetrating power, enabling them to penetrate deep into tissues and precisely irradiate tumors. Currently, photon beam sources used in brachytherapy are divided into two categories: gamma-ray sources based on radioactive isotopes and X-ray sources that generate bremsstrahlung radiation by targeting electron accelerators.

[0004] Existing bremsstrahlung-based X-ray sources typically use thermionic cathodes as electron emission sources. By heating the cathode filament to over 1000°C, electrons escape from the cathode. The emitted electron beam bombards the anode target under high voltage at the anode, generating X-rays for radiotherapy through bremsstrahlung radiation. These sources are all connected to an external high-voltage source via thin, high-voltage cables to provide the high voltage for electron acceleration. While they offer advantages such as high controllability, good radiation quality, and high radiation safety, problems related to high temperature and high voltage transmission limit their application as neutron sources in brachytherapy. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a miniature wireless pyroelectric X-ray source that does not require a high-voltage power supply, does not require heating the cathode to generate electrons, has low power consumption, and can generate X-rays wirelessly, enabling remote control.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] A miniature wireless pyroelectric X-ray source includes: a conversion target, a target adapter ring, an insulating shell, an optical fiber, a graphene electrode, a pyroelectric crystal, a crystal adapter, a getter, and a laser transmission window.

[0008] One end of the target adapter ring is connected to the conversion target.

[0009] The target adapter ring is located at one end of the insulating housing, and the optical fiber is located at the other end of the insulating housing.

[0010] One end of the pyroelectric crystal is connected to the graphene electrode; the other end of the pyroelectric crystal is grounded and connected to the crystal adapter.

[0011] One end of the laser transmission window is connected to the crystal adapter, and the other end of the laser transmission window is connected to the optical fiber.

[0012] The getter is configured to be sleeved on the crystal adapter.

[0013] The conversion target, target adapter ring, insulating shell, graphene electrode, pyroelectric crystal, crystal adapter, getter, and laser transmission window are all encapsulated within the insulating shell, forming a sealed vacuum cavity environment.

[0014] The miniature wireless pyroelectric X-ray source provided in at least one embodiment of this disclosure also includes a windowed adapter ring.

[0015] Both the optical fiber and the insulating housing are fixedly connected to the windowed adapter ring.

[0016] The laser transmission window is located on the windowed adapter ring, and the laser emitted from the optical fiber enters the insulating tube after passing through the laser transmission window.

[0017] In at least one embodiment of the present disclosure, the graphene electrode comprises a Ni substrate on which multiple layers of vertical graphene are grown.

[0018] In at least one embodiment of the present disclosure, a micro wireless pyroelectric X-ray source is provided, wherein the conversion target is internally coated.

[0019] In at least one embodiment of the miniature wireless pyroelectric X-ray source provided in this disclosure, the coating is one of W film, Au film, Ta film and Cu film.

[0020] In at least one embodiment of the miniature wireless pyroelectric X-ray source provided in this disclosure, the thickness of the coating is 0.1-10 μm.

[0021] In at least one embodiment of the miniature wireless pyroelectric X-ray source provided in this disclosure, the getter is arranged in a ring shape.

[0022] In at least one embodiment of the present disclosure, a first conductive and thermally conductive adhesive layer is disposed between the Ni substrate and the pyroelectric crystal.

[0023] The Ni substrate and the pyroelectric crystal are both bonded and fixed together by the first conductive and thermally conductive adhesive layer.

[0024] In at least one embodiment of the present disclosure, a miniature wireless pyroelectric X-ray source is provided, wherein a second conductive and thermally conductive adhesive layer is disposed between the crystal adapter and the pyroelectric crystal.

[0025] The crystal adapter and the pyroelectric crystal are bonded and fixed together by the second conductive and thermally conductive adhesive layer.

[0026] In at least one embodiment of the present disclosure, a miniature wireless pyroelectric X-ray source is provided with a graphite coating on the end of the crystal adapter facing the laser transmission window.

[0027] The beneficial effects of this invention are as follows: It employs laser-based remote heating of a pyroelectric crystal material, causing a temperature change to obtain a high negative voltage. This further enables vertical graphene to emit electrons, which are then accelerated and used to strike a target, generating X-rays. Compared to existing technologies, this technique eliminates the need for a high-voltage power supply and cathode heating to generate electrons, resulting in low power consumption. It can also generate X-rays wirelessly, enabling remote control and significantly expanding the application scenarios of the technology.

[0028] In use, this miniature X-ray source is implanted near the tumor tissue, serving as a neutron source. A fiber optic connector is pre-installed in the skin. An external laser is used to irradiate the connector. The laser beam travels through the fiber to the laser transmission window of the miniature X-ray source, then through the window to irradiate and heat the crystal adapter. The adapter transfers this heat to the connected pyroelectric crystal, causing a temperature change. The temperature rise is controlled within 30-50°C, generating a negative high-voltage on one end of the pyroelectric crystal. Simultaneously, a graphene electrode is attached to this end. The high voltage causes the graphene electrode to emit and accelerate electrons. These accelerated electrons bombard the conversion target, generating bremsstrahlung radiation and thus X-rays. These X-rays pass through the conversion target and irradiate the tumor tissue, causing its biological activity to be deactivated, thereby achieving the therapeutic purpose. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a three-dimensional view of a miniature wireless pyroelectric X-ray source in Example 1.

[0031] Figure 2 This is a schematic diagram of the internal structure of a miniature wireless pyroelectric X-ray source in Example 1.

[0032] Figure 3 This is a three-dimensional view of a miniature wireless pyroelectric X-ray source in Example 2.

[0033] Figure 4 This is a schematic diagram of the internal structure of a miniature wireless pyroelectric X-ray source in Example 2.

[0034] In the picture:

[0035] 1. Conversion target; 2. Target adapter ring; 3. Insulating shell; 4. Windowed adapter ring; 5. Optical fiber; 6. Graphene electrode; 7. Pyroelectric crystal; 8. Crystal adapter; 9. Getter; 10. Laser transmission window; 11. Planar conversion target; 12. Planar target adapter ring; 13. Conical insulating shell; 14. Planar crystal adapter; 15. Circular pyroelectric crystal; 16. Circular graphene electrode; 17. Ring-shaped getter. Detailed Implementation

[0036] The technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments, not all embodiments.

[0037] To address the limitations of current bremsstrahlung-based X-ray sources, which suffer from high temperatures and high voltage transmission issues that restrict their application as neutron sources in brachytherapy, this invention aims to propose a miniature wireless pyroelectric X-ray source. This source eliminates the need for a high-voltage power supply and cathode heating to generate electrons, resulting in low power consumption. It generates X-rays wirelessly, enabling remote control. Its compact size facilitates implantation near tumor tissue for use as a neutron source, eliminates the risk of high-voltage leakage, and allows for flexible and convenient shutdown.

[0038] Example 1

[0039] like Figure 1 and 2 As shown, this embodiment provides a miniature X-ray source device for brachytherapy, which adopts a needle-tube structure and specifically includes a conversion target 1, a target adapter ring 2, an insulating shell 3, a windowed adapter ring 4, an optical fiber 5, a graphene electrode 6, a pyroelectric crystal 7, a crystal adapter seat 8, a getter 9, and a laser transmission window 10. To ensure that this needle-tube miniature X-ray source device can stably generate X-rays, each component, after specific connections, needs to be vacuum-sealed within the insulating shell to form a sealed vacuum chamber environment, and the vacuum level can be maintained for a long time.

[0040] The conversion target 1 is a pointed cylindrical structure, entirely made of Be material. The diameter of the thicker end is 3-5 mm, the diameter of the thinner end is 1-2 mm, the height is 5 mm, and the thickness of the thinner end is 0.05-0.5 mm. It serves as a Be window, allowing the generated X-rays to pass through and improving X-ray transmittance. The thicker end connects to the target adapter ring 2 via laser welding or brazing. The interior of the conversion target is coated with materials such as W, Au, Ta, and Cu, with a thickness of 0.1-10 μm. Its function is to generate X-rays after electron bombardment.

[0041] The target adapter ring 2 is made of Kovar alloy material, with an outer diameter of 3-5mm and an inner diameter of 2-4mm. One end is connected to the conversion target 1, and the other end is connected to the insulating tube shell 3. The connection method is either laser welding or brazing. Its function is to act as a sealing device between metal and ceramic or glass to ensure the airtightness of the vacuum device.

[0042] The insulating shell 3 is made of alumina ceramic material, specifically 99% ceramic, 95% ceramic, or glass. The glass can be either quartz glass or high-silica glass. The outer diameter of the insulating shell 3 is 3-5mm, the inner diameter is 2-4mm, and the length is 20-30mm. One end is connected to the target adapter ring 2, and the other end is connected to the windowed adapter ring 4. The connection method is either laser welding or brazing. Its function is high-voltage insulation and fixed support.

[0043] The windowed adapter ring 4 is made of Kovar alloy, with an outer diameter of 3-5 mm and an inner diameter of 1-3 mm. One end of the windowed adapter ring 4 is connected to the insulating tube shell. The laser enters the device after passing through the optical fiber 5 and the laser transmission window 10.

[0044] Fiber 5 uses biocompatible clad fiber such as acrylate or ETFE, with a non-magnetic ceramic ferrule or a metal ferrule with good thermal conductivity. The core diameter is 200-550μm, the cladding diameter is 240-600μm, the spectral range is 200-2400nm, and the transmitted laser power is 2-20W. Its function is to serve as a laser transmission medium, enabling the transmission of laser light from an external laser device through an optical fiber connector to the interior of a miniature X-ray source inside the body. The laser undergoes total internal reflection inside the source, thereby achieving long-distance optical transmission.

[0045] The graphene electrode 6 adopts a structure in which multiple layers of vertical graphene are grown on a Ni substrate. The diameter of the Ni substrate is 1-3 mm and the thickness of the Ni substrate is 0.5-1 mm. The Ni substrate is connected to the pyroelectric crystal 7 by bonding with conductive and thermally conductive adhesive. The vertical graphene has a height of 1-10 μm and its function is to generate cold electron emission with a field enhancement factor greater than 2000.

[0046] The pyroelectric crystal 7 is made of lithium tantalate or lithium niobate, with a diameter of 1-3mm and a thickness of 5-10mm. It is z-phase cut and its function is to change the spontaneous polarization of the crystal by changing the temperature of the crystal, so as to generate a negative high voltage at one end. The high voltage end of the pyroelectric crystal 7 is connected to the Ni substrate of the graphene electrode 6, and the other end is grounded and connected to the crystal adapter 8. The connection method is to bond it with conductive and thermally conductive adhesive.

[0047] The crystal adapter 8 is made of a material with good thermal conductivity such as Ag, Cu or graphite, with a diameter of 1-3 mm and a thickness of 3-5 mm. One end of the crystal adapter 8 is connected to the pyroelectric crystal 7, and the other end is assembled with the laser transmission window 10. Its function is to absorb the laser light passing through the laser transmission window 10 and transfer the laser energy to the pyroelectric crystal 7, causing its temperature to rise. In order to improve the absorption rate of laser light, the end of the metal crystal adapter 8 facing the laser transmission window 10 is provided with a graphite coating (not shown).

[0048] The getter 9 is made of metals such as titanium, zirconium, and vanadium, and their alloys. The getter 9 has a ring-shaped structure with an outer diameter of 1.6-3.6 mm, an inner diameter of 0.8-2.4 mm, and a height of 1-3 mm. The getter 9 is fitted onto the crystal adapter 8, and its function is to maintain the vacuum level inside the miniature X-ray source below 10 after high-temperature activation. -3 Pa.

[0049] The laser transmission window 10 is made of GaF2 material and is embedded in the windowed adapter ring 4 to maintain a vacuum and prevent air leakage. One end of the laser transmission window 10 is connected to the crystal adapter 8, and the other end is connected to the optical fiber 5 through an optical fiber connector.

[0050] Example 2

[0051] like Figure 3 and 4 As shown, this embodiment provides a miniature X-ray source device for brachytherapy, which adopts a button-type structure, specifically including a planar conversion target 11, a planar target adapter ring 12, a conical insulating shell 13, an optical fiber 5, a circular graphene electrode 16, a circular pyroelectric crystal 15, a planar crystal adapter 14, an annular getter 17, and a laser transmission window 10. To ensure that this needle-type miniature X-ray source device can stably generate X-rays, each component, after specific connections, needs to be vacuum-sealed within the insulating shell to form a sealed vacuum chamber environment, and the vacuum level can be maintained for a long time.

[0052] The planar conversion target 11 is a dome-shaped structure, entirely made of Be material. Its upper diameter is 8-28 mm, its lower diameter is 10-30 mm, its height is 1.5-3 mm, and its upper thickness is 0.05-0.5 mm. It serves as a Be window, allowing generated X-rays to pass through and improving X-ray transmittance. The planar conversion target is internally coated with a material chosen from W, Au, Ta, and Cu, with a thickness of 0.1-10 μm. This coating is used to generate X-rays after electron bombardment.

[0053] The planar target adapter ring 12 is made of Kovar alloy material, with an outer diameter of 10-30mm and an inner diameter of 8-28mm. One end of the planar target adapter ring 12 is connected to the planar conversion target 11, and the other end is connected to the conical insulating shell 13. The connection method is laser welding or brazing. Its function is to act as a sealing device between metal and ceramic or glass to ensure the airtightness of the device.

[0054] The conical insulating shell 13 is made of alumina ceramic material, specifically 99% ceramic, 95% ceramic, or glass. The glass can be quartz glass or high-silica glass. The conical insulating shell 13 has a cone bottom diameter of 10-30mm, a cone top diameter of 5-7mm, a height of 4-6mm, and a cone sidewall angle of 165°. The cone bottom is connected to the planar target adapter ring 12, and the cone top is connected to the optical fiber through a connector. The connection method is either laser welding or brazing. Its function is high-voltage insulation and fixed support.

[0055] Fiber 5 uses biocompatible clad fiber such as acrylate or ETFE, with a non-magnetic ceramic ferrule or a metal ferrule with good thermal conductivity. The core diameter is 200-550μm, the cladding diameter is 240-600μm, the spectral range is 200-2400nm, and the transmitted laser power is 2-20W. Its function is to serve as a laser transmission medium, enabling the transmission of laser light from an external laser device through an optical fiber connector to the interior of a miniature X-ray source inside the body. The laser undergoes total internal reflection inside the source, thereby achieving long-distance optical transmission.

[0056] The circular graphene electrode 16 adopts a structure in which multiple layers of vertical graphene are grown on a Ni substrate. The diameter of the Ni substrate is 8-26 mm, the thickness of the Ni substrate is 0.5-1 mm, and the height of the vertical graphene is 1-10 μm. Its function is to generate cold electron emission, and its field enhancement factor is greater than 2000.

[0057] The circular pyroelectric crystal 15 is made of lithium tantalate or lithium niobate. The circular pyroelectric crystal 15 is frustum shaped with a large end diameter of 8-26mm, a small end diameter of 1-3mm, and a height of 3-5mm. It is Z-phase cut. Its function is to change the spontaneous polarization of the crystal by changing the crystal temperature, thereby generating a negative high voltage at the large end. The large end of the circular pyroelectric crystal 15 is connected to the Ni substrate of the circular graphene electrode 16, and the other end is grounded and connected to the planar crystal adapter 14. The connection method is to bond it with conductive and thermally conductive adhesive.

[0058] The planar crystal adapter 14 is made of materials with good thermal conductivity such as Ag, Cu, and graphite, with a diameter of 3-5 mm and a thickness of 1-3 mm. One end is connected to the circular pyroelectric crystal 15, and the other end is assembled with the laser transmission window 10. Its function is to absorb the laser light passing through the laser transmission window 10 and transfer the laser energy to the circular pyroelectric crystal 15, causing its temperature to rise. In order to improve the absorption rate of laser light, the metal planar crystal adapter 14 is provided with a graphite coating (not shown) on the end facing the laser transmission window 10.

[0059] The annular getter 17 is made of metals such as titanium, zirconium, and vanadium, or their alloys. The annular getter 17 has a circular structure with an outer diameter of 5-7 mm, an inner diameter of 3-5 mm, and a height of 0.5-1 mm. The annular getter 17 is fitted onto the planar crystal adapter 14. Its function is to maintain the vacuum level inside the miniature X-ray source below 10 after high-temperature activation. -3 Pa.

[0060] The laser transmission window 10 is made of GaF2 material and is embedded in a conical insulating tube shell 13 to maintain a vacuum and prevent air leakage. One end of the laser transmission window 10 is connected to the planar crystal adapter 14, and the other end is connected to the optical fiber 5 through an optical fiber connector.

[0061] Although embodiments of this application have been shown and described above, the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be conceived without inventive effort should be covered within the scope of protection of this invention. Unless expressly stated otherwise, no element, action or instruction used herein should be construed as critical or necessary.

Claims

1. A miniature wireless pyroelectric X-ray source, characterized in that, include: Conversion target, target adapter ring, insulating shell, optical fiber, graphene electrode, pyroelectric crystal, crystal adapter, getter and laser transmission window; One end of the target adapter ring is connected to the conversion target; The target adapter ring is located at one end of the insulating tube shell, and the optical fiber is located at the other end of the insulating tube shell; One end of the pyroelectric crystal is connected to the graphene electrode; the other end of the pyroelectric crystal is grounded and connected to the crystal adapter. One end of the laser transmission window is connected to the crystal adapter, and the other end of the laser transmission window is connected to the optical fiber; The getter is configured to be sleeved on the crystal adapter, and the getter is used to maintain the vacuum level inside the miniature X-ray source after high-temperature activation; The conversion target, target adapter ring, insulating shell, graphene electrode, pyroelectric crystal, crystal adapter, getter and laser transmission window are all encapsulated in the insulating shell, forming a sealed vacuum cavity environment. The graphene electrode includes a Ni substrate on which multiple layers of vertical graphene are grown. The getter is arranged in a ring shape and is fitted onto the planar crystal adapter. The getter is used to maintain the vacuum level inside the miniature X-ray source after high-temperature activation. A first conductive and thermally conductive adhesive layer is disposed between the Ni substrate and the pyroelectric crystal. The Ni substrate and the pyroelectric crystal are both bonded and fixed together by the first conductive and thermally conductive adhesive layer. A second conductive and thermally conductive adhesive layer is provided between the crystal adapter and the pyroelectric crystal. The crystal adapter and the pyroelectric crystal are bonded and fixed together by the second conductive and thermally conductive adhesive layer.

2. The miniature wireless pyroelectric X-ray source according to claim 1, characterized in that, It also includes a windowed adapter ring; Both the optical fiber and the insulating tube are fixedly connected to the windowed adapter ring. The laser transmission window is located on the windowed adapter ring, and the laser emitted from the optical fiber enters the insulating tube after passing through the laser transmission window.

3. A miniature wireless pyroelectric X-ray source according to claim 1 or 2, characterized in that, The conversion target has an internal coating.

4. A miniature wireless pyroelectric X-ray source according to claim 3, characterized in that, The coating is one of W film, Au film, Ta film and Cu film.

5. A miniature wireless pyroelectric X-ray source according to claim 3, characterized in that, The thickness of the coating is 0.1-10 μm.

6. A miniature wireless pyroelectric X-ray source according to claim 1 or 2, characterized in that, The end of the crystal adapter facing the laser transmission window is coated with a graphite coating.

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