Ultrasonic freeze ablation catheters and probes

A catheter kit for the necrosis of tissue cells in a patient, comprising a catheter and ultrasonic cavitation means, said catheter comprising:

• (i) a first elongated tube adapted to flow tissue freezing fluid therein, said fluid being pumped from a source thereof external to said catheter, said first elongated tube having an imaginary axis and distal and proximal ends;
• (ii) a second elongated tube coaxial with the first elongated tube and spaced externally therefrom to form an annular space therebetween adapted to flow fluid therein, said second elongated tube having distal and proximal end;
• (iii) a head member connected to the distal ends of the first and second tubes and adapted to contact the tissue cells and apply freezing temperatures in the range of about -10.degree. C. to about -50.degree. C. to the contacted tissue cells to thereby freeze said tissue cells at the point of contact;
• the head member having fluid flow mens to receive the flow of freezing fluid and to be cooled therefrom;
• said ultrasonic cavitation means for generating an ultrasonic beam in the frequency range of from about 7.5 MHz to about 130 MHz to create a field coextensive with the tissue caused by the head portion to be at the freezing temperature, said ultrasonic beam having a power level of from about 1 milliwatt to about 300 milliwatts in the coextensive field;
• whereby the ultrasonic cavitation causes intracellular nucleation in the cells resulting in cell freezing and cell necrosis.