Sam S Wong

US Patent:

54337178, Jul 18, 1995

Filed:

Mar 23, 1993

Appl. No.:

8/035455

Inventors:

Boris Rubinsky - Albany CA
John Gilbert - Berkeley CA
Sam Wong - Emeryville CA
Mark Roos - San Francisco CA
Grant Pease - Oakland CA

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

A61B 1736

US Classification:

606 20

Abstract:

Methods and apparatus for magnetic resonance imaging (MRI) assisted cryosurgery. Optimal probe placements and cooling parameters are calculated prior to cryosurgery using MRI data. A MRI compatible cryoprobe and a stereotactic probe positioning device are provided. The resolution of MR images is enhanced by mounting a radio frequency MR coil on the intracorporeal end of a cryoprobe. During cryosurgery the temperature distribution in the frozen region is solved by determining the boundary of the frozen region and solving the heat equation for the known boundary conditions. During cryosurgery the temperature distribution in the unfrozen region is determined by T1 measurements. The process of freezing is controled using information from the solution of the energy equation in the frozen region and temperature measurements in the unfrozen region. After cryosurgery the extent of the tissue damage may be ascertained using phosphorus-31 and/or sodium-23 spectroscopy with a special coil set on the cryosurgical probe.