Microwave plasma sterilisation system and applicators therefor
A sterilization system having a controllable non-ironing microwave radiation source for providing microwave energy for combining with a gas to produce atmospheric low temperature plasma for sterilizing biological tissue surfaces or the like. A plasma generating region may be contained in a hand held plasma applicator. The system may include an impedance adjustor e.g. integrated in the plasma applicator arranged to set a plasma strike condition and plasma sustain condition. The gas and microwave energy may be transported to a plasma generating region along an integrated cable assembly. The integrated cable assembly may provide a two way gas flow arrangement to permit residual gas to be removed from the surface. Invasive surface plasma treatment is therefore possible. The plasma applicator may have multiple plasma emitters to produce a line or blanket of plasma.
1. An integrated cable assembly for transporting simultaneously microwave energy and gas to an electrosurgical instrument, the integrated cable assembly comprising a coaxial transmission line inside a sheath, the coaxial transmission line being formed from an inner conductor, an outer conductor and a dielectric material separating the inner conductor from the outer conductor,
wherein the inner conductor has a longitudinal bore therethrough for transporting gas to the electrosurgical instrument, and
wherein the integrated cable assembly comprises a longitudinal passageway formed between an outer wall of the outer conductor and an inner wall of the sheath for transporting residual gas away from the electrosurgical instrument.
2. The integrated cable assembly of claim 1 , wherein the longitudinal passageway terminates at a reservoir from which the gas is re-introduced to the longitudinal bore.
3. The integrated cable assembly of claim 1 , wherein the coaxial transmission line comprises a flexible tube made from the dielectric material, and wherein the inner conductor is conductive coating on an inner surface of the flexible tube and the outer conductor is a conductive coating on the outer surface of the flexible tube.
4. The integrated cable assembly of claim 1 having an outer diameter equal to or less than 3 mm.
5. The integrated cable assembly of claim 1 , wherein the sheath is supported on the outer conductor using a plurality of spacers.
6. The integrated cable assembly of claim 5 , wherein the plurality of spacers contain a plurality of holes or perforations to permit gas flow.