Patent ID: 6496738
Filing Date: 2002-12-17
Classification: A61B,A61F,A61M,H05B

Abstract:
Microwave heating apparatus for heating fluid or tissue, said apparatus comprisingan elongated catheter for placement adjacent to high dielectric/high loss organic fluid or tissue in a patient, said catheter having a distal end and a proximal end and including an antenna adjacent to said distal end and a cable having one end connected to said antenna and a second end; a transmitter for producing a transmitter signal capable of heating said fluid or tissue; a first receiver for receiving a first signal having a first frequency indicative of thermal radiation from a first depth in said fluid or tissue and producing a first output signal in response thereto; a second receiver for receiving a second signal having a second frequency indicative of thermal radiation from a second depth in said fluid or tissue and producing a second output signal in response thereto; active and passive diplexers connected in series between said transmitter and the second end of said cable, said active diplexer including switch means operable between the transmitter, the passive diplexer and the second receiver; control means for controlling the switch means so that when the transmitter is transmitting, the transmitter signal is coupled to the passive diplexer but not to the second receiver and when the transmitter is not transmitting, any second signal from the passive diplexer is coupled to the second receiver but not to the transmitter, said passive diplexer coupling said transmitter signal received via the active diplexer only to said antenna, while coupling a first signal received from the antenna only to the first receiver so that the apparatus can heat said fluid or tissue and determine the actual temperature of the fluid or tissue at two different depths.