摘要:
A surgical antenna for radiating microwave energy (e.g. frequency 500 MHz to 60 GHz) from a e.g. ceramic insertion tip (60) into biological tissue is disclosed. The tip is provided at the end of an elongate body which delivers the microwave energy to the tip via an inner conductor (30), an outer conductor (20) surrounding the inner conductor and a dielectric material (50) therebetween. The impedance of the insertion tip (60) is selected to improve impedance matching with the complex conjugate of the complex impedance of the tissue at a treatment frequency. For example the insertion tip may act as or include at least one quarter wavelength impedance transformer. By closely matching the antenna's impedance to the tissue, dynamic tuning (if used) can be performed much more efficiently. Impedance matching at the tip can also focus the radiated energy distribution.
摘要:
A rollbar safety frame for an agricultural or industrial tractor comprises two uprights joined at their upper ends by a cross-member, and is adjustable so that it may fit different types of tractor. The frame is adjustable at its upper end, its lower end, or both. For adjustment at the upper end, the cross member is securable between the uprights such that the distance therebetween is adjustable. For adjustment at the lower end, each upright carries a securing plate provided with means for adjusting the relative positions of securing bolts transversely of an axle about which the uprights are secured. The safety frame may, if desired, be hinged at a central portion such that, when secured to a tractor, it may be folded.
摘要:
A calibration method and apparatus for surgical antennas which are arranged to deliver microwave radiation (e.g. having a treatment frequency of 500 MHz to 100 GHz) into biological tissue is disclosed. An emitting region of the antenna is exposed to a plurality of calibration standards each having a different complex impedance at the treatment frequency. In one embodiment the calibration standards are created in a short-circuit-terminated waveguide cavity of variable length. In another embodiment, each calibration standard is a different mixture of two or more liquids. Measurement of the magnitude and phase of signals reflected from the emitting region when exposed to the calibration standard can permit calibration of the antenna, e.g. by generating a mapping function based on the measured values and known or reference values for the calibration standards. Also disclosed is tissue treatment apparatus having an ablation channel for conveying microwave radiation to a surgical antenna at a high power level and a separate measurement channel for conveying microwave radiation to a surgical antenna at a low power level, wherein the measurement channel bypasses noisy components on the ablation channel. A surgical antenna having an impedance transformer for matching an e.g. coaxial feed structure which terminates in one or more radiating elements with tissue to be treated is also disclosed.
摘要:
A surgical antenna for radiating microwave energy (e.g. frequency 500 MHz to 60 GHz) from a e.g. ceramic insertion tip (60) into biological tissue is disclosed. The tip is provided at the end of an elongate body which delivers the microwave energy to the tip via an inner conductor (30), an outer conductor (20) surrounding the inner conductor and a dielectric material (50) therebetween. The impedance of the insertion tip (60) is selected to improve impedance matching with the complex conjugate of the complex impedance of the tissue at a treatment frequency. For example the insertion tip may act as or include at least one quarter wavelength impedance transformer. By closely matching the antenna's impedance to the tissue, dynamic tuning (if used) can be performed much more efficiently. Impedance matching at the tip can also focus the radiated energy distribution.
摘要:
A calibration method and apparatus for surgical antennas which are arranged to deliver microwave radiation (e.g. having a treatment frequency of 500 MHz to 100 GHz) into biological tissue is disclosed. An emitting region of the antenna is exposed to a plurality of calibration standards each having a different complex impedance at the treatment frequency. In one embodiment the calibration standards are created in a short-circuit-terminated waveguide cavity of variable length. In another embodiment, each calibration standard is a different mixture of two or more liquids. Measurement of the magnitude and phase of signals reflected from the emitting region when exposed to the calibration standard can permit calibration of the antenna, e.g. by generating a mapping function based on the measured values and known or reference values for the calibration standards. Also disclosed is tissue treatment apparatus having an ablation channel for conveying microwave radiation to a surgical antenna at a high power level and a separate measurement channel for conveying microwave radiation to a surgical antenna at a low power level, wherein the measurement channel bypasses noisy components on the ablation channel. A surgical antenna having an impedance transformer for matching an e.g. coaxial feed structure which terminates in one or more radiating elements with tissue to be treated is also disclosed.
摘要:
A probe and associated apparatus for treating oesophageal tissue with microwave radiation (e.g. radiation having a frequency of 5-60 GHz) are disclosed. The probe comprises a flexible substrate that expands and retracts between an access configuration, e.g. suitable for insertion through an endoscope, and a treatment configuration in which radiating elements, e.g. conducting patches, monopole antennas, slots in a conducting strip or the like, are brought into close proximity with tissue to be treated. The radiating elements are arranged to emit a substantially uniform electromagnetic field with a suitable penetration depth into the tissue. The apparatus can monitor and control the power delivered from the probe into tissue. A method of hollow tube, e.g. oesophageal, pathological treatment and a device for opening and closing the probe are also disclosed.