Ablation Innovation for Quality Care
You can count on MedWaves’ microwave ablation system that provides you with the control and flexibility to deliver the quality care that you and your patients. In addition, MedWaves helps you work cost-effectively to meet the financial demands of today’s healthcare market. Practitioners in many medical disciplines throughout the world have found that MedWaves systems are easy to use, while exceeding performance expectations in terms of safety and predictability. Safety and predictability require strict control of the energy used for ablation. The MedWaves generators and probes use intelligent feedback to control both the temperature and frequency unlike any other microwave ablation systems. In addition, MedWaves systems can address a wide range of tissue types, while minimizing damage to adjacent tissue. A wide range of antenna sizes precisely cover large and small areas of ablation. And, MedWaves systems do not requiring any cooling mechanisms.
The Science of Microwave Ablation
Microwaves are electromagnetic waves with frequencies that range from 300 MHz and 300 GHz. These waves when used on diseased soft-tissue cause tissue necrosis via heat. Heating of the diseased soft-tissue takes place when microwave energy causes water molecules in the tissue to rotate, generating frictional energy that causes the temperature in the diseased tissue to increase1. Temperatures must be at a certain point (see chart below2) before cell death can occur.
For microwave energy, which operates at a frequency of 915 MHz, the wavelength is very short in soft-tissue (e.g., 5cm in liver3) and the wave is distributed in the field, in very close proximity to the antenna. The wave can only move a short distance before the polarity of the antenna is changed (915 million times per second). It is this change in polarity that causes the dipoles in water molecules to align themselves each time the field changes direction, and it is this rotation in the water molecules that causes heating of the tissue and subsequent cell death.
1 Simon CJ et al. Microwave Ablation: Principles and Applications. RadioGraphics 2005; 25:S69-S83. 2 Rhim H et al. Essential Techniques for Successful Radiofrequency Thermal Ablation of Malignant Hepatic Tumors. RadioGraphics 2001; 21:S17-S35. 3 Gabriel C. Compilation of the dielectric properties of body tissues at RF and microwave frequencies. Report N.AL/OE-TR- 1996-0037, Occupational and environmental health directorate, Radiofrequency Radiation Division, Brooks Air Force Base, Texas (USA), June 1996.
Microwave Ablation Overview
Microwaves are used to destroy or ablate diseased soft-tissue by heating the tissue to a temperature that causes cell death. Heating of the tissue takes place because the microwave energy causes the water molecules in the diseased soft-tissue to rotate. This rotation of the water molecules causes friction, which in turn causes the tissue to heat up. The generator produces microwave energy which is transmitted through the antennas and into the patient. The microwave energy is delivered to the diseased soft-tissue through antennas (needles) which are placed inside the patient using imaging guidance, such as CT (computed tomography) or ultrasound. The antennas can also be used during an open surgical procedure to target and ablate the diseased soft-tissue.