27/04/04 ©
Söring
Users manual RF-units
1
not valid for MBC600
-9-
HF-Generator
RF-generator
Aktive-Elektrode
active electrode
biologisches Gewebe
biological tissue
Neutral-Elektrode
Patient electrode
Fig 3.1. Shows the principle of RF Surgery
3.1.1 Reaction of biological tissue to local overheating
If RF voltage (continuous sine signal) reaches a certain upper limit, an arc will occur at the
contact zone of the active electrode to the tissue. This leads to a quick heating of the intercellular
fluid. This vaporization of the intercellular fluid results in a bursting of the cells and the tissue
looses its cohesion i.e., the electrode cuts.
Lower RF voltages (below 150v
eff
) lead to a slower heating of the tissue, resulting in coagulation
with no tissue separation.
Short RF impulses with high voltage lead to a build-up of sparks together with a strong surface
coagulation.
