Method and apparatus for monitoring and controlling tissue temperature and lesion formation in radio-frequency ablation procedures
US6423057B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 2000 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Jan 21, 2020 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2018/00875
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Impedance and capacitance-related parameters are monitored in the electrical circuit of a tissue-ablation apparatus wherein RF electrical power is administered at predetermined frequencies. Tissue temperature has been found to correlate well with low-frequency impedance, or with the resistive component of impedance at any frequency. Therefore, one or both of these parameters are calculated and tracked during the ablation procedure to estimate tissue temperature. Similarly, tissue lesion formation has been found to correlate well with changes in the capacitive component of tissue impedance. Thus, this parameter can be used to track tissue lesion formation during the ablation procedure. The ratio of tissue-to-blood interface with the ablation electrode is estimated by measuring impedance at a very low frequency and a very high frequency. The difference between these two values divided by the high-frequency value is taken to be a measure of such ratio. Alternatively, other electrical parameters indicative of changes in the capacitive component of the system may be measured and the ratio is calculated as a function of these changes with respect to a baseline value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.