Patent ID: 6320932
Filing Date: 2001-11-20
Classification: A61N,H01J

Abstract:
A therapeutic radiation source, comprising:A. a flexible catheter extending along a probe axis between a proximal end and a distal end of the catheter, the flexible catheter comprising optical delivery means extending along said probe axis and having an originating end and a terminating end, and adapted for transmitting optical radiation incident on said originating end to said terminating end;B. an optical source, including means for generating a beam of optical radiation directed to said originating end of said optical delivery means;C. a radiation source coupled to said terminating end of said optical delivery means, comprising a substantially rigid housing enclosing an electron source and a target, said housing defining a substantially evacuated interior region extending along a beam axis between said electron source at an input end of the housing and a radiation transmissive window at an output end of the housing,a. wherein said electron source and said target are disposed along said beam axis and spaced apart from and opposite each other;b. wherein said electron source is adapted to emit electrons in response to optical radiation transmitted to said terminating end, and comprises a thermionic emitter having an electron emissive surface; andc. wherein said target is responsive to incident electrons to emit therapeutic radiation whereby therapeutic radiation emitted therefrom is directed through the radiation transmissive window; andD. means for establishing an accelerating electric field extending between said electron source toward said target, the electric field acting to accelerate electrons emitted from said electron source toward said target;wherein said optical delivery means are adapted for directing a beam of optical radiation transmitted therethrough to impinge upon said surface of said thermionic emitter, and wherein said beam of transmitted optical radiation has a power level sufficient to heat at least a portion of said surface to an electron emitting temperature so as to cause thermionic emission of electrons from said surface.