Implantable microwave antennas for thermal therapy

The purpose of this article is to review the physical construction and power deposition characteristics of interstitial microwave antennas that may be used for highly localized heating of tissue at depth in the human body. Several different antenna designs are described and matched with potential clinical applications that range from moderate temperature Hyperthermia therapy to tissue-necrosing Thermal Ablation therapy. Typical clinical procedures are outlined for thermal treatment of target sites such as brain, prostate, heart, and gynecologic region tissues. Associated methods of implanting the antennas and coupling microwave energy into the surrounding tissue are also described, including the use of single or multi-chamber stiff flexible or inflatable balloon type catheters, with or without circulating air or mater cooling. With numerous references to the primary literature, this material should provide a framework for analyzing potential new applications for interstitial microwave antennas, as derived from the physical capabilities and limitations of the available hardware and techniques.