CN-122000671-A - Low-radiation high-directivity antenna structure for microwave thermotherapy

Abstract

The invention provides a low-radiation high-directivity antenna structure for microwave hyperthermia, and relates to the technical field of medical microwave equipment antennas. The microwave antenna comprises an antenna radiator, two grounded metal columns, a metal substrate and a coaxial hose, wherein the metal substrate is in sealing connection with one side of a microwave heating cavity, the two grounded metal columns are positioned in the microwave heating cavity, the grounded metal columns are perpendicular to the metal substrate and are arranged on the metal substrate, the two grounded metal columns are arranged at intervals and symmetrically, the antenna radiator is parallel to the metal substrate and is arranged on the upper part of the grounded metal columns, one end of the coaxial hose is connected with the antenna radiator, and the other end of the coaxial hose penetrates through the metal substrate and is positioned on the outer side of the microwave heating cavity and is used for externally connecting a solid-state microwave source. The reflection surface structure formed by the elevated antenna radiator and the grounded metal column effectively inhibits side lobe radiation by controlling the current return path and electromagnetic field distribution, forms a concentrated main lobe, ensures that microwave energy is precisely projected to a target tissue region, and improves treatment depth and precision.

Inventors

• YANG YANG
• ZHU HUACHENG
• YANG FENGMING
• LAN DUO

Assignees

• 四川大学

Dates

Publication Date

20260508

Application Date

20260211

Claims (8)

1. 1. The low-radiation high-directivity antenna structure for microwave thermal therapy is arranged on a microwave heating cavity and is characterized by comprising an antenna radiator, two grounded metal columns, a metal substrate and a coaxial hose; The metal substrate is connected with one side of the microwave heating cavity in a sealing way, two grounding metal columns are positioned in the microwave heating cavity, the grounding metal columns are perpendicular to the metal substrate and are arranged on the metal substrate, the two grounding metal columns are arranged at intervals and symmetrically, the antenna radiator is parallel to the metal substrate and is arranged on the upper part of the grounding metal columns; one end of the coaxial hose is connected with the antenna radiator, and the other end of the coaxial hose penetrates through the metal substrate and is positioned at the outer side of the microwave heating cavity and is used for being externally connected with a solid-state microwave source.
2. 2. A low-emissivity high directivity antenna structure for microwave hyperthermia according to claim 1, wherein the antenna radiator is made of a highly conductive metal material including but not limited to one of copper, aluminum and stainless steel.
3. 3. The low-emissivity high-directivity antenna structure for microwave hyperthermia according to claim 1, wherein the antenna radiator has a quality factor ranging from 3 to 8.
4. 4. The low-emissivity high-directivity antenna structure for microwave hyperthermia according to claim 1, wherein the antenna radiator has a rectangular parallelepiped structure, and a U-shaped groove is provided in the antenna radiator.
5. 5. A low-emissivity high-directivity antenna structure for microwave hyperthermia according to claim 1, wherein the connection of the coaxial hose and the antenna radiator is the center position of the antenna radiator.
6. 6. A low-emissivity high-directivity antenna structure for microwave hyperthermia according to claim 1, wherein the antenna radiator and the grounded metal posts together form a reflecting surface structure for suppressing side lobe radiation and forming a concentrated main lobe.
7. 7. A low-emissivity high-directivity antenna structure for microwave hyperthermia according to claim 1, characterized in that the antenna radiator can withstand an input power of 300W.
8. 8. The low-radiation high-directivity antenna structure for microwave hyperthermia according to claim 1, wherein the coaxial hose outer layer is made of bending-resistant and high-temperature-resistant insulating material, and the interface part is a rapid plug-in structure.

Description

Low-radiation high-directivity antenna structure for microwave thermotherapy Technical Field The invention relates to the technical field of medical microwave equipment antennas, in particular to a low-radiation high-directivity antenna structure for microwave thermotherapy. Background Microwave hyperthermia is a treatment method which utilizes high-frequency electromagnetic waves to generate a thermal effect in human tissues, and the basic principle is that microwaves act on water molecules in the tissues, so that the water molecules are rubbed at a high speed to generate heat, and the temperature is locally increased. The moderate temperature rise (about 40-45 ℃) can improve blood circulation, relieve inflammation and pain, and the higher temperature (more than 45 ℃) can induce apoptosis or necrosis of tumor cells, so that the microwave hyperthermia can be used for the adjuvant treatment of tumors, and can also be widely applied to inflammatory diseases and rehabilitation physiotherapy. Compared with the traditional infrared or radio frequency heating, the microwave has stronger penetrating power and better temperature control precision, and can realize non-invasive heating of subcutaneous or deep tissues. In recent years, microwave hyperthermia has also developed minimally invasive techniques such as microwave ablation and microwave scalpels, which exhibit unique advantages in tumor ablation, tissue cutting and hemostasis. However, existing devices still suffer from deficiencies in energy focusing, directivity control, energy utilization, and radiation suppression. In the prior art, the most common microwave hyperthermia scheme adopts an open dipole antenna or a coaxial probe and other structures. The structure is based on the natural diffusion principle of microwave radiation, and can provide a certain therapeutic effect for heating superficial tissues. An improved coaxial microwave hyperthermia probe is proposed as in patent US5190054a, by employing a spiral winding or cutting variable size notches in the outer conductor, which results in a more uniform heating pattern in the axial and radial directions. However, the design and manufacturing process is complex, the requirements on the micrometer-scale spiral pitch or notch machining precision are extremely high, the cost and mass production difficulty are increased, the spiral winding part of the flexible probe can be loosened or broken in the inserting or bending process, the notch structure of the rigid probe can weaken the integral strength, and in addition, the lack of an active cooling and real-time temperature feedback mechanism still has limited clinical adaptability and safety, and the problems can influence the popularization and application of the flexible probe in actual medical treatment. Furthermore, studies have shown that when the antenna structure lacks directional control, microwave energy is prone to leak to non-target tissues, creating unnecessary radiation risks, reducing therapeutic safety. In clinical application, the individual difference of patients and the change of tissue electrical parameters are more remarkable, and the traditional antenna structure has no capability of compensating the complex conditions, so that the focusing effect expected by design is greatly reduced in practical application. As patent document CN214074723U proposes a microwave thermal therapeutic apparatus with adjustable mounting position, an electric telescopic rod lifting mechanism and a motor reducer rotating mechanism are arranged on a base, so as to realize the adjustment of a physiotherapy head in the vertical direction and the horizontal direction, and sliding wheels with brakes are arranged at four corners of the base so as to move and fix the physiotherapy head. Although the scheme improves the convenience of position adjustment, the problems of complex structure, increased cost, insufficient safety protection measures and the like still exist, and the comprehensive requirements of the microwave thermal therapy equipment on flexibility, stability and safety in clinical application cannot be fundamentally solved. The core of the phase control heating uniformity is that the electromagnetic fields of all radiation units in target tissues are coherently overlapped by utilizing the phase control of a multi-antenna or patch array and the instantaneous energy peak value continuously moves in the tissue section by quickly changing the phase combination, and the local temperature is not as fast as the response to the instantaneous peak value but is expressed as time average power distribution because the scanning speed is far faster than the thermal diffusion time constant of the tissues, thereby macroscopically forming a uniform thermal field, realizing the effective heating of deep tissues and avoiding local overheating. In the existing microwave hyperthermia technology, a common scheme is to adopt a single-point or double-waveguide antenna structure