1. RF Technology
• Devices based on mono or bi-polar Radio Frequency technologies are used almost exclusively for tissue ablation and vessel sealing.
• With RF technology electrical current is passed between two opposite electrodes, while the tissue acts as its conductor and becomes heated as a result. However, since tissue is not a homogeneous medium (fat, muscles, etc.) its electrical (ohmic) resistance may vary from point to point causing non-uniform heating of treated tissue. Also, as temperature rises, treated tissue becomes desiccated and more resistant to additional ohmic heating.
• Thus, not only the temperatures of the treated tissue cannot be accurately controlled with RF technologies, its several negative side-effects may present significant health risk to the patient, such as: charring of tissue, instrument sticking to the tissue (opposite electrodes cannot be coated with non-sticking material like Teflon, as it would not allow electrical current to flow), unpredictable pass of current through patient body (in case of mono-polar technology).
2. Microwave Technology
• Devices utilizing Microwave technology are mostly used for tissue ablation.
• With Microwave technology, the tissue heating occurs when electromagnetic waves travel through the tissue causing its heating. However, since tissue is not a homogeneous medium (fat, muscles, etc.) , just likes with of RF technology, uniform heating of treated tissue is not possible.
• In addition, not only the temperatures of treated tissue cannot be accurately controlled, but penetration depth of Microwave waves cannot be accurately controlled either. That causes unwanted damage to tissues in areas where the treatment was not intended. This technology cannot be used for vessel sealing.